JP2009002210A - Injection control device for internal combustion engine - Google Patents

Abstract

An air-fuel ratio is appropriately controlled when a catalyst is warmed up with stratified combustion.
An ECU that controls an in-cylinder direct injection engine performs a lower limit guard value setting process. In this processing, when the catalyst rapid warm-up control is performed using the learning value corresponding to the light load region among the learning values of the injection amount correction value learned in advance for each load region, the learning value is reflected. A lower limit guard value efgafxgd for limiting is set. This lower limit guard value is set to, for example, 95% of the average value of a plurality of learning values corresponding to the high load region. On the other hand, when the learning value corresponding to the light load region shifts to the decrease side when the factor that shifts the learning value is not due to the diluted fuel, as a result of limiting the reflection of the learning value, when the air-fuel ratio enters the rich region below the theoretical air-fuel ratio, The lower limit guard value efgafxgd is gradually reduced, and the guard is relaxed. This lower limit guard gradual reduction process is continued until the air-fuel ratio reaches the stoichiometric air-fuel ratio.
[Selection] Figure 8

Description

  The present invention relates to a technical field of an injection control device for an internal combustion engine that controls an injection amount of fuel in an internal combustion engine having an injection means capable of directly injecting fuel into a cylinder.

  As this type of apparatus, an apparatus that considers dilution of engine oil with fuel (hereinafter referred to as “fuel dilution” as appropriate) has been proposed (see, for example, Patent Document 1). According to the control device for an internal combustion engine disclosed in Patent Document 1 (hereinafter referred to as “conventional technology”), when the degree of fuel dilution is large, the learning value relating to the feedback correction amount of the fuel injection amount is stored. By prohibiting it, it is possible to prevent the air-fuel ratio from becoming lean with respect to the target air-fuel ratio at the time of cold start.

  In addition, in the air-fuel ratio correction at the time of starting the engine, there is also proposed a method in which a lower limit value of the air-fuel ratio correction coefficient is set according to the engine temperature at the time of starting so as not to become too lean (for example, see Patent Document 2). .

  In addition, when the stored air-fuel ratio learning value is applied at the time of restart, when the correction is greatly made with respect to the basic amount, there is also proposed a method for decreasing the learning value in accordance with a decrease in the coolant temperature (for example, And Patent Document 3).

JP 2007-32324 A Japanese Patent No. 3789336 JP-A-5-133262

  The so-called air-fuel ratio feedback control, in which the air-fuel ratio is fed back to correct the injection amount, is basically prohibited from being executed during the catalyst warm-up with stratified combustion. Therefore, in this case, the learning value of the injection amount obtained during the warm period is often used for determining the injection amount. However, in the conventional technology, when the degree of fuel dilution is large, storage of the learned value itself is prohibited, so that the control accuracy of the air-fuel ratio may be extremely lowered during such a period.

  On the other hand, in such a cold start period, the fuel used for fuel dilution (hereinafter referred to as “diluted fuel” where appropriate) is difficult to evaporate. It is difficult to avoid leaning of the fuel ratio. In other words, the conventional technology has a technical problem that it is difficult to avoid a deterioration in emissions due to the difficulty in suppressing a decrease in control accuracy of the air-fuel ratio during a period of catalyst warm-up with stratified combustion. There is a point.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an injection control device for an internal combustion engine that can suppress deterioration of emissions during a period in which catalyst warm-up with stratified combustion is performed. .

  In order to solve the above-described problems, an internal combustion engine injection control device according to the present invention is provided in a vehicle, and includes an internal combustion engine having a catalyst device and injection means capable of injecting fuel into a cylinder. One correction value selected according to the load of the internal combustion engine from a plurality of correction values to be reflected in at least the fuel injection amount learned for each load region of the internal combustion engine based on the air-fuel ratio And a control means for controlling the injection means so that the fuel corresponding to the determined injection quantity is injected, and the catalyst device is in an unwarmed state. The injection amount is determined based on execution means for executing catalyst rapid warm-up control including stratified combustion of the fuel under predetermined conditions including at least the above and the correction value corresponding to a predetermined light load region Is When the catalyst rapid warm-up control is executed in the case, characterized by comprising a restricting means for restricting the reflection of the correction value corresponding to the low load region to the injection quantity.

  The internal combustion engine injection control apparatus according to the present invention can take the form of various processing units such as an ECU (Electronic Control Unit), various controllers or various computer systems such as a microcomputer device during operation. The determining means determines the fuel injection amount.

  For the internal combustion engine according to the present invention, for example, various detection means such as an air-fuel ratio sensor and an oxygen concentration sensor to the extent that problems due to fuel adhesion due to low cylinder inner wall temperature or intake port inner wall temperature are not practically manifested. The internal combustion engine to such an extent that the catalytic device can effectively purify the exhaust without problems in practice, or the deterioration of the combustion performance due to the relatively low engine temperature is not practically manifested. After the engine is warmed up (hereinafter, the state of the internal combustion engine is appropriately referred to as a “warm state”), a correction value to be reflected in the injection amount is learned for each load region based on the air-fuel ratio. For example, it is stored in an appropriate storage means. The determining means determines the injection amount based on one correction value selected from the plurality of correction values according to the load of the internal combustion engine at that time.

  Here, the “correction value” refers to a basic value (that is, a basic injection amount) of an injection amount set in advance for each operation region defined by a physical quantity to be corrected, for example, engine speed and load, or the like. A concept that includes numerical values that can be used directly or indirectly for various correction calculations for the purpose of converging the air-fuel ratio to the target air-fuel ratio, etc. is there. As long as the correction value is reflected at least in some form, the determination process of the injection amount by the determining means includes, for example, the correction value or the correction term including the correction value in the basic injection amount or the corrected term, for example. It includes various modes such as multiplication, addition, subtraction, or division, and is set through a process different from the correction value. For example, cooling water temperature, lubricating oil temperature, outside air temperature, humidity, fuel property, etc. In other words, other correction calculations based on various correction values, correction coefficients, correction terms, or the like set according to the above may be added.

  When the injection amount is determined, for example, fuel corresponding to the determined injection amount is injected by control means that can take the form of various processing units such as an ECU, various controllers or various computer systems such as a microcomputer device. An injection means such as an electronically controlled direct injection injector provided in the internal combustion engine is controlled, and fuel is directly injected into the cylinder of the internal combustion engine.

  On the other hand, according to the injection control device for an internal combustion engine according to the present invention, the internal combustion engine is in an unwarmed state by execution means that can take the form of various processing units such as an ECU, various controllers or various computer systems such as a microcomputer device. The catalyst rapid warm-up control is executed under predetermined conditions including at least the above.

  Here, “catalyst rapid warm-up control” includes at least control for causing stratified combustion of fuel, for example, various catalyst devices such as a three-way catalyst, an oxidation catalyst, or an NSR catalyst (NOx storage reduction catalyst) at least at a catalyst activation temperature. This is a concept that encompasses the control that is performed so that the internal combustion engine is warmed up as early as possible by raising the temperature as described above. As a preferred mode for stratifying the fuel, the fuel injection is performed in the compression process (that is, if the fuel injection is basically performed in the intake process during the warm period, the delay of the injection timing is reduced). Done). Further, in view of the purpose of raising the temperature of the catalyst device, as a suitable form for the rapid catalyst warm-up control, the exhaust gas temperature rise control by retarding the ignition timing (the air-fuel mixture is discharged after being discharged from the cylinder). Including combustion). In stratified combustion, it is possible to make the air-fuel ratio of the entire internal combustion engine lean by directionally forming a fuel atmosphere around the plug of the ignition device. This also includes control that makes the target air-fuel ratio lean.

  Catalyst rapid warm-up control involves stratified combustion of fuel. When stratified combustion is performed, fuel is concentrated around the spark plug, so the atmosphere around the plug tends to be rich in the air-fuel ratio, and misfire may occur if the air around the plug becomes excessively rich. There is sex. However, when a misfire occurs, oxygen in the exhaust gas remains without being consumed, so the air-fuel ratio estimated based on the exhaust gas is easily determined to be lean. Accordingly, if the injection amount is controlled while the air-fuel ratio is fed back during the catalyst rapid warm-up control (hereinafter, such control is referred to as “air-fuel ratio F / B control” as appropriate), the air-fuel ratio is originally rich. Nevertheless, it is determined that the air-fuel ratio is lean, the amount of fuel is increased, and there is a problem that the air-fuel ratio is further enriched around the plug. For this reason, during the catalyst rapid warm-up control, the air-fuel ratio F / B control is basically prohibited, and the fuel injection amount is, for example, the correction value of the injection amount (which will be referred to as “ Also referred to as “learned value”).

  On the other hand, in this type of internal combustion engine in which fuel is directly injected into the cylinder, for example, fuel adhering to the cylinder inner wall (for example, a bore) is injected into lubricating oil such as engine oil that is circulated and supplied through the internal combustion engine. By being taken in, the above-described fuel dilution occurs. The diluted fuel taken into the lubricating oil by this fuel dilution evaporates as the temperature of the lubricating oil rises, and is returned to the intake system via a control valve such as a PCV, for example, and again used for combustion.

  Here, since the learning of the correction value of the injection amount is preferably performed during a warm period in which such evaporation of the diluted fuel occurs at a constant or indefinite rate, the presence of such diluted fuel is considered. However, the influence of the diluted fuel on the correction value greatly depends on the load state of the internal combustion engine. That is, if the target air-fuel ratio is constant, the injection amount becomes relatively large in the high load region where the intake air amount is large, and the influence of the diluted fuel is inevitably reduced. On the other hand, in the light load region where the intake air amount is small, the injection amount becomes relatively small, and the influence of the diluted fuel inevitably increases. The large influence of the diluted fuel preferably means that the degree to which the injection amount determined based on the correction value is reduced is large.

  Here, in particular, when the catalyst rapid warm-up control is at least in a state where the catalyst device is not warmed up (practical judgment is made that the catalyst device is not warmed up based on the cooling water temperature, the lubricating oil temperature, etc.). The internal combustion engine during the rapid catalyst warm-up control is at least relatively cold. Therefore, the evaporation of the diluted fuel is relatively difficult to occur. When the learning value in consideration of the presence of the evaporated diluted fuel is used in a situation where the diluted fuel is not evaporated or hardly generated, the fuel is likely to be insufficient with respect to the required amount, and the air-fuel ratio is likely to be made lean. As described above, since the influence of the diluted fuel on the learning value is small in the high load region, such a problem is unlikely to occur. However, in the light load region where the influence of the diluted fuel is large, the injection amount decreases as described above. Due to the tendency, in some cases, misfire due to air-fuel ratio lean may occur and emission may deteriorate.

  Therefore, in the injection control device for an internal combustion engine according to the present invention, for example, correction corresponding to the light load region by the action of the limiting means that can take the form of various processing units such as an ECU, various controllers or various computer systems such as a microcomputer device. Generation | occurrence | production of the malfunction by performing catalyst rapid warm-up control in the condition where a value is used is suppressed. That is, when the catalyst rapid warm-up control is executed in the case where the injection amount is determined based on the correction value corresponding to the light load region, the limiting means determines the correction value corresponding to the light load region to the injection amount. Limit reflection.

  Here, the “light load region” according to the present invention refers to a single or a plurality of load regions corresponding to a part of the load region where the correction value is learned. For example, when learning of correction values is performed in a plurality of stages of load areas set in advance, the “light load area” according to the present invention includes one or a plurality of areas including the lightest area as a preferred embodiment. It is a load area. In other words, when the diluted fuel does not evaporate during the execution of the catalyst rapid warm-up control, the air-fuel ratio is made lean enough to reveal problems that cannot be overlooked in practice, such as misfires. Refers to the load area.

  In addition, “restricting reflection” is a concept encompassing that the degree of reflection of the correction value to the injection amount is somewhat reduced as compared with the case where no restriction of this kind is made. In other words, the scope of the concept may be free. For example, the limiting means may limit the reflection of the correction value by determining the injection amount after making the correction value appropriate, or by providing a lower limit value for the correction value or the fuel injection amount.

  As a result of limiting the reflection of the correction value in this way, an excessive decrease in the injection amount (for example, a decrease in the injection amount that causes misfire due to the fact that the diluted fuel does not evaporate) is suppressed, and at least the air-fuel ratio is reduced. Lean misfire is avoided. In addition, since the use of the correction value corresponding to the light load region is not necessarily prohibited, it is possible to reflect the correction value in the light load region to the injection amount to some extent without any problem in practice, and the catalyst rapid warm-up is possible. The control accuracy of the air-fuel ratio during the control does not decrease at least to the extent that causes practical problems. That is, according to the injection control apparatus for an internal combustion engine according to the present invention, it is possible to suppress the deterioration of the emission during the rapid catalyst warm-up control.

  In one aspect of the injection control apparatus for an internal combustion engine according to the present invention, the vehicle has an input shaft connected to an engine output shaft of the internal combustion engine and an output shaft connected to an axle, and has a predetermined traveling range. A transmission device capable of automatically switching a rotation speed ratio between the input shaft and the output shaft among a plurality of preset rotation speed ratios when selected; The case where the injection amount is determined based on the correction value corresponding to the light load region corresponds to the light load region when the travel range is selected or when the cooling water temperature of the internal combustion engine is equal to or higher than a reference value. Limit the reflection of correction values.

  According to this aspect, the vehicle is provided with a transmission such as an AT (Automatic Transmission) or a CVT (Continuously Variable Transmission), and the rotational speed ratio between the input shaft and the output shaft. (Hereinafter referred to as “speed ratio” as appropriate) can be switched automatically from a plurality of preset rotation speed ratios, for example, stepwise or continuously.

  Such automatic switching control of the gear ratio is, for example, travel defined as a shift position for traveling the vehicle, such as D range (or 1 range, 2 range, or 3 range). This is done when a range is selected. When the travel range is selected, for example, a P range or an N range (hereinafter referred to as “non-travel range” as appropriate) is selected that is not a shift position where the vehicle travels. Unlike the case, it is necessary to ensure the brake negative pressure of the vehicle. Accordingly, the load state of the internal combustion engine is changed to a light load state (that is, a state in which the negative pressure is relatively large, for example, through throttle control of the throttle valve opening (hereinafter referred to as “throttle opening” as appropriate)). Controlled).

  On the other hand, when the cooling water temperature of the internal combustion engine is relatively high, the combustion performance is relatively improved. Therefore, the engine speed increases under the same conditions. Therefore, the load state of the internal combustion engine is controlled to a light load state in order to relatively reduce the engine speed. The reference value of the cooling water temperature according to the present invention refers to a value that defines whether or not it is necessary to reduce the load, for this reason. As a result, when the running range is selected or when the conditions for executing the catalyst rapid warm-up control are satisfied in a situation where the coolant temperature is equal to or higher than the reference value, the correction selected to be used for correcting the injection amount The value necessarily corresponds to the light load region.

  According to this aspect, since the reflection of the correction value is limited in such a case, the catalyst rapid warm-up control needs to be performed in a state where the travel range is selected, or the cooling water temperature is the reference value, that is, When it is necessary to perform rapid catalyst warm-up control in a state in which the correction value corresponding to the light load region is equal to or greater than a value that is a criterion for determining whether or not to use, it is possible to suppress the deterioration of emission. .

  Note that when the catalyst non-traveling range is selected or when the catalyst rapid warm-up control is performed in a state where the coolant temperature is lower than the reference value, the injection amount correction value corresponds to the high load region. Since it is selected, the control accuracy of the air-fuel ratio is easily ensured, and the deterioration of the emission is not easily realized. Therefore, according to this aspect, even if the vehicle emission (that is, on-mode emission) in a predetermined operation mode (hereinafter, referred to as “on-mode” as appropriate), an operation mode that does not correspond to such an operation mode ( Hereinafter, it is possible to prevent the deterioration by ensuring the accuracy of the air-fuel ratio even if the vehicle emission (that is, referred to as “off-mode” as appropriate)) is ensured, and this is extremely useful in practice. .

  In one aspect of the injection control apparatus for an internal combustion engine according to the present invention, the limiting means is configured to use the light load based on the correction value corresponding to a high load region set on a higher load side than the light load region. Limit the reflection of the correction value corresponding to the area.

  According to this aspect, the reflection of the correction value corresponding to the light load region is limited based on the correction value corresponding to the high load region set on the higher load side than the light load region. Therefore, it is possible to easily limit the reflection of the correction value, and by using the correction value originally set for the same internal combustion engine, the leaning of the air-fuel ratio can be more effectively suppressed. It becomes possible.

  In one aspect of the injection control device for an internal combustion engine according to the present invention in which the reflection of the correction value is limited based on the correction value corresponding to the high load region, the correction value corresponding to the high load region is the value of the correction value. The average value of the plurality of correction values corresponding to the plurality of load regions including the load region on the highest load side and the load region adjacent to the load region on the highest load side.

  According to this aspect, the average value of the plurality of correction values corresponding to the plurality of load regions corresponding to the high load region is used to limit the reflection of the correction values corresponding to the light load region. Therefore, even if the reliability of the correction value in the high load area is not ensured due to, for example, erroneous learning of the correction value, the influence can be reduced, and the robustness related to the limitation of the correction value in the light load area can be reduced. Sex is guaranteed. In this case, the load area related to learning of the correction value is subdivided under any form, and the load area on the highest load side and a plurality of load areas including the load areas adjacent thereto are targeted. Therefore, the influence of fuel dilution can be eliminated as much as possible.

  In another aspect of the injection control apparatus for an internal combustion engine according to the present invention, in which the reflection of the correction value is limited based on the correction value corresponding to the high load region, the magnitude of the correction value depends on the magnitude of the injection amount. The limiting means reflects the correction value corresponding to the light load region within a range equal to or higher than a lower limit guard value calculated based on the correction value corresponding to the high load region. Reflect to the injection amount.

  According to this aspect, the correction value to be learned takes a form such as a correction ratio to be multiplied by the value of the injection amount to be corrected, for example, and the injection amount is determined so that the magnitude corresponds to the magnitude of the injection amount. Reflected. Here, the limiting means is calculated based on a correction value corresponding to the high load area (for example, a correction value corresponding to the high load area minus a value of about several percent), ie, a lower limit guard value (that is, a light weight). In the load region, the correction value is reduced by the amount corresponding to the diluted fuel) and is reflected in the injection amount in a range of more than (which is a concept that can be easily replaced with “larger” depending on the setting of the lower limit guard value). Therefore, it provides extremely high profits in practice, such as reliably reducing the lean air-fuel ratio due to the fact that the diluted fuel does not evaporate, while improving the accuracy of the air-fuel ratio by relying on the correction value corresponding to the light load region to some extent. Is done.

  In another aspect of the injection control device for an internal combustion engine according to the present invention, in which the reflection of the correction value is limited based on the correction value corresponding to the high load region, the correction value corresponding to the light load region and the high load region Prohibiting means for prohibiting the execution of the rapid catalyst warm-up control when the injection amount is determined based on the correction value corresponding to the light load region when the deviation from the corresponding correction value is equal to or greater than a predetermined value. It has.

  Here, in the learning of the correction value of the injection amount, even if the correction value shifts to the decrease side (side to decrease the injection amount) in the light load region (that is, the injection amount is further decreased), the factor is It may not be due to diluted fuel. In such a case, when the catalyst rapid warm-up control using the correction value corresponding to the light load region is performed, if the reflection of the correction value corresponding to the light load region is limited as described above, the injection amount that should be reduced originally Therefore, the air-fuel ratio of the internal combustion engine gradually begins to become richer. As a result, particularly when the deviation is large, the air-fuel ratio becomes excessively rich and the emission may be extremely deteriorated. That is, there is a possibility that although the catalyst device is intended to be warmed up early to reduce the emission, the emission may be deteriorated.

  According to this aspect, the rapid catalyst warm-up control when the deviation is equal to or larger than the predetermined value is prohibited by the prohibiting means that can take the form of various processing units such as an ECU, various controllers or various computer systems such as a microcomputer device. Is done. That is, the execution of the rapid catalyst warm-up control in a situation where it is difficult to ensure the control accuracy of the air-fuel ratio is prohibited, and it is possible to suppress the deterioration of the emission.

  In this aspect, the predetermined value of the deviation may be set based on an increase value of the injection amount during a period in which the internal combustion engine is in an unwarmed state and the catalyst rapid warm-up control is not executed.

  In this case, the predetermined value related to the deviation is referred to as, for example, a low temperature increase value, an increase value after warm-up, or an increase value after start-up, and is set or calculated according to, for example, the elapsed time after start-up or the cooling water temperature. In the period when the catalyst rapid warm-up control is not performed, the fuel injection amount is set based on an increase value of the injection amount in consideration of fuel wall adhesion and combustion efficiency decrease due to engine non-warm-up. That is, if the deviation is greater than, for example, this increased value or a value obtained by adding a constant or indefinite margin to this increased value, it is more effective to inhibit the rapid catalyst warm-up control and perform such an increase. Therefore, this kind of increase value is practically effective as an index that defines a predetermined value of the deviation that defines whether or not the catalyst rapid warm-up control can be executed.

  In another aspect of the injection control apparatus for an internal combustion engine according to the present invention, the control unit further includes a specifying unit that specifies the air-fuel ratio, and the limiting unit is configured such that when the specified air-fuel ratio is less than a predetermined value, The degree to which the reflection of the correction value corresponding to the light load region is limited is relaxed.

  According to this aspect, the air-fuel ratio of the internal combustion engine is specified by specifying means that can take the form of various processing units such as an ECU, various controllers or various computer systems such as a microcomputer device. Here, “specific” according to the present invention refers to, for example, detecting directly or indirectly as a physical numerical value or an electrical signal corresponding to the physical numerical value via some detection means, or appropriate storage means. Select or estimate the corresponding numerical value from a map or the like stored in, etc., according to a preset algorithm or calculation formula from the detected physical numerical value or electrical signal or the selected or estimated numerical value A wide range that includes deriving as a result of logical operation, numerical operation, or electrical or mechanical control, or simply acquiring the value detected, selected, estimated or derived as an electrical signal, etc. It is a concept. Within such a concept, the specifying means is, for example, an electrical signal corresponding to the detection result of the air-fuel ratio and oxygen concentration in various detection means such as an air-fuel ratio sensor and an oxygen concentration sensor installed in the exhaust system of the internal combustion engine. The air-fuel ratio may be specified based on the above.

  As already described, when the reason why the correction value corresponding to the light load region is shifted to the decrease side compared to the high load region is not due to the diluted fuel, the air-fuel ratio is gradually increased by limiting the reflection of the correction value. Start enriching. On the other hand, when the catalyst rapid warm-up control is executed, as described above, there is a possibility of misfire, so the reliability of the specified air-fuel ratio tends to be low. That is, more specifically, there may be a situation where it is detected that the air-fuel ratio is lean even though the plug periphery is rich.

  However, in a situation where it is determined that the air-fuel ratio is less than a predetermined value set as, for example, the theoretical air-fuel ratio or a value close to the theoretical air-fuel ratio, that is, at least in a relatively rich region (predetermined value). If the value is the stoichiometric air fuel ratio or a value near the stoichiometric air fuel ratio (that is, in the situation where it is judged that the air fuel ratio is truly rich), no misfire has occurred. Even if it is trusted, the possibility of suffering practical disadvantages is low.

  Therefore, the limiting means relaxes, for example, the degree of limiting the reflection of the correction value corresponding to the light load region continuously, stepwise, or binary when the air-fuel ratio is less than a predetermined value. For this reason, according to this aspect, when the correction value corresponding to the light load region is not affected by the diluted fuel (that is, when the injection amount should be corrected to the reduction side due to other factors), the light load region is quickly entered. The corresponding correction value can be reflected in the correction of the injection amount. Therefore, the deterioration of the emission due to the rich air-fuel ratio is suppressed, and the emission during the rapid catalyst warm-up control can be suppressed over a wide range.

  In this aspect, the limiting means may relax the degree of limiting the reflection of the correction value corresponding to the light load region until the air-fuel ratio becomes equal to or higher than a predetermined value.

  In this case, the air-fuel ratio can be maintained at a predetermined value, which is practically beneficial.

  Such an operation and other advantages of the present invention will become apparent from the embodiments described below.

<Embodiment of the Invention>
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

<Configuration of Embodiment>
First, the configuration of a vehicle 10 according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic configuration diagram conceptually and schematically showing the main configuration of the vehicle 10.

  1, a vehicle 10 includes an ECU 100, an engine 200, a torque converter 300, an ECT (Electronic Controlled Transmission) 400, an ECT drive unit 500, and a hydraulic controller 600 according to the present invention. Is an example.

  The ECU 100 is an electronic control unit that includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and controls the entire operation of the vehicle 10. It is an example of a “control device”. The ECU 100 is configured to be able to execute a catalyst rapid warm-up control and a lower limit guard value setting process, which will be described later, according to a control program stored in the ROM.

  The ECU 100 is an integrated electronic control unit that functions as an example of the “injection control device for an internal combustion engine” according to the present invention. Therefore, each operation in the “determination unit”, “control unit”, “execution unit”, “restriction unit”, and “prohibition unit” according to the present invention is executed by the ECU 100. However, the physical, mechanical and electrical configurations of the respective means according to the present invention are not limited to this, and for example, these include various computer systems such as a plurality of ECUs, various processing units, various controllers or microcomputer devices. Etc. may be configured.

  The engine 200 is an in-line four-cylinder gasoline engine that is configured to function as a power source of the vehicle 10 and has an in-cylinder direct injection type fuel injection mode, which is an example of an “internal combustion engine” according to the present invention. Here, the detailed configuration of the engine 200 will be described with reference to FIG. FIG. 2 is a schematic diagram of the engine 200. In the figure, the same reference numerals are given to the same portions as those in FIG. 1, and the description thereof will be omitted as appropriate.

  The “internal combustion engine” in the present invention has, for example, a plurality of cylinders, and when fuel that can take various forms such as gasoline, alcohol, or a mixed fuel thereof is burned in a combustion chamber in each of the plurality of cylinders. An engine capable of outputting at least a part of the generated power to a vehicle axle via an engine output shaft such as a crankshaft via a mechanical transmission path such as a piston and a connecting rod, and fuel is For example, it is a concept encompassing an engine having a so-called “direct injection” mode in which fuel is directly injected into a cylinder through injection means such as an electronically controlled injector. However, as long as a part of the fuel is injected in the form of direct injection, the internal combustion engine according to the present invention may be provided with injection means for injecting fuel into the intake port. That is, the internal combustion engine according to the present invention may be a so-called dual injection internal combustion engine.

  In FIG. 2, an engine 200 burns an air-fuel mixture through an ignition operation by an ignition device 202 in which a part of a spark plug (not shown) is exposed in a combustion chamber in a cylinder 201, and an explosive force due to such combustion. The reciprocating motion of the piston 203 that occurs in response to the above is converted into the rotational motion of the crankshaft 205 (that is, an example of the “engine output shaft” according to the present invention) via the connecting rod 204. Yes.

  In the vicinity of the crankshaft 205, a crank position sensor 206 for detecting the rotational position (ie, crank angle) of the crankshaft 205 is installed. The crank position sensor 206 is electrically connected to the ECU 100, and the ECU 100 is configured to calculate the engine speed NE of the engine 200 based on the crank angle signal output from the crank position sensor 206. ing.

  The engine 200 is an in-line four-cylinder engine in which four cylinders 201 are arranged in series in a direction perpendicular to the paper surface. However, since the configurations of the individual cylinders 201 are equal to each other, in FIG. Only the cylinder 201 will be described. Further, the number of cylinders and the arrangement form of each cylinder in the internal combustion engine according to the present invention are not limited to those of the engine 200. For example, a 6-cylinder, 8-cylinder, or 12-cylinder engine may be used. It may be a facing type or the like, and can take various forms.

  In the engine 200, air sucked from outside passes through a cleaner and an intake pipe 207 (not shown) and is guided to a throttle valve 208. The throttle valve 208 is controlled in its drive state by a throttle valve motor 209 electrically connected to the ECU 100, and controls the intake air amount as the amount of air sucked into the cylinder 201 by controlling the drive state. It has become. The ECU 100 basically controls the throttle valve motor 209 so as to obtain a throttle opening corresponding to the accelerator opening, but without the driver's intention through the operation control of the throttle valve motor 209. It is also possible to adjust the throttle opening. That is, the throttle valve 208 is configured as a kind of electronically controlled throttle valve.

  The intake air that has passed through the throttle valve 208 is guided to the intake port 210. The communication state between the inside of the cylinder 201 and the intake port 210 is controlled by opening and closing the intake valve 211. The intake valve 211 is configured to open and close in accordance with a cam profile of an intake cam (not shown) fixed to an intake camshaft (not shown). The intake air is guided into the cylinder 201 when the intake valve 211 is opened.

  On the other hand, in the engine 200, fuel is stored in the fuel tank 213. A low pressure pipe 214 is connected to the fuel tank 213, and fuel is pumped up from the fuel tank 213 by a feed pump 215 provided in the low pressure pipe 214 and supplied to the high pressure pump 216. .

  The high-pressure pump 216 is configured to be able to supply (i.e., discharge) fuel supplied via the low-pressure pipe 214 to the common rail 217. The high-pressure pump 216 is electrically connected to the ECU 100, and the operation state is controlled by the ECU 100.

  Here, with reference to FIG. 3, the detailed structure of the high-pressure pump 216 will be described with its operation. FIG. 3 is a schematic configuration diagram conceptually showing the configuration of the high-pressure pump 216. In the figure, the same reference numerals are given to the same portions as those in FIG. 2, and the description thereof will be omitted as appropriate.

  In FIG. 3, the high-pressure pump 216 mainly includes an electromagnetic spill valve 2162, a pump plunger 2164, and a discharge valve 2166.

  The electromagnetic spill valve 2162 is an electromagnetic opening / closing valve provided on the low pressure pipe 214. The electromagnetic spill valve 2162 is electrically connected to the ECU 100, and the opening / closing operation thereof is controlled by the ECU 100. The operation state of the electromagnetic spill valve 2162 takes a binary state of valve opening or valve closing, and the valve closing time is determined according to the drive duty under the control of the ECU 100. In other words, the electromagnetic spill valve 2162 is open when no power is supplied, that is, when the drive duty is 0%, and is closed for a time corresponding to the drive duty. The electromagnetic spill valve 2162 may be configured to close when the drive duty is 0% and open for a time corresponding to the drive duty.

  One end of the low-pressure pipe 214 is connected to the pump cylinder 2163. The pump plunger 2164 is configured to be capable of reciprocating along the longitudinal direction of the pump cylinder 2163 inside the pump cylinder 2163. This reciprocating motion is controlled by a cam profile of a pump drive cam 2167 fixed to the exhaust camshaft 224 of the engine 200. That is, the pump plunger 2164 has an upper end portion between the TDC (Top Death Center) and the BDC (Bottom Death Center) while the pump driving cam 2167 makes one rotation. Configured to reciprocate.

  Inside the pump cylinder 2163, a pressurizing chamber 2165 is formed by the inner wall portion of the pump cylinder 2163 and the upper end portion of the pump plunger 2164. The volume of the pressurizing chamber 2165 changes with the reciprocating motion of the pump plunger 2164, and becomes the minimum when the upper end of the pump plunger 2164 is at TDC. Fuel is supplied to the pressurizing chamber 2165 via the low-pressure pipe 214 while the electromagnetic spill valve 2162 is open. One end of a high-pressure pipe 2161 is connected to the pump cylinder 2163. The high-pressure pipe 2161 includes a discharge valve 2166 and is connected to the common rail 217 at the other end.

  Under such a configuration, the ECU 100 closes the electromagnetic spill valve 2162 for a time corresponding to the drive duty during the period in which the pump plunger 2164 moves from the BDC shown in the figure toward the TDC and the pressure in the pressurizing chamber 2165 increases. . In the state where the electromagnetic spill valve 2162 is closed, the communication between the pressurizing chamber 2165 and the low pressure pipe 214 is cut off, so that the fuel is pressurized and the discharge valve 2166 provided in the high pressure pipe 2161 is pushed open to open the common rail. It is discharged to 217.

  As described above, in the high-pressure pump 216, fuel is discharged to the common rail 217 in accordance with the driving duty for driving the electromagnetic spill valve 2162 (that is, the larger the driving duty is). This discharge amount is always feedback-controlled so that the rail pressure as the fuel pressure in the common rail 217 is maintained at the target pressure.

  Returning to FIG. 2, the common rail 217 is a storage unit configured to be able to store fuel at a higher pressure than the fuel tank 213. The common rail 217 is common to the four cylinders 201 and extends in a direction perpendicular to the paper surface.

  A direct injection injector 212 corresponding to each cylinder 201 is connected to the common rail 217. The direct injection injector 212 has a part of its injection hole (not shown) exposed inside the cylinder 201 and can directly inject high-pressure fuel stored in the common rail 217 into the high-temperature and high-pressure cylinder 201. 1 is an electronically controlled fuel injection device as an example of the “injection means” according to the present invention.

  The direct injection injector 212 is electrically connected to the ECU 100, and its operation state is controlled by the ECU 100 to the upper level. More specifically, the direct injection injector 212 includes an injection valve that regulates the amount of fuel injected through the injection hole in accordance with its open / closed state, and the valve opening time of the injection valve is controlled by the ECU 100. It has a configuration. From the direct injection injector 212, fuel corresponding to an injection amount that can be determined by the valve opening time of the injection valve and the rail pressure of the common rail 217 is injected.

  Inside the cylinder 201, the air sucked through the intake valve 211 and the fuel injected from the direct injection injector 212 are mixed to form the above-described air-fuel mixture. The air-fuel mixture that is used for combustion inside the cylinder 201 or that is not used for partial combustion becomes exhaust gas, and corresponds to a cam profile of an exhaust cam (not shown) fixed to an exhaust camshaft 224 (not shown in FIG. 2). When the exhaust valve 218 that opens and closes is opened, the exhaust port 219 and the exhaust pipe 220 communicating with the exhaust port 219 are exhausted.

  A three-way catalyst 222 is installed in the exhaust pipe 220. The three-way catalyst 222 is a catalyst capable of purifying CO (carbon monoxide), HC (hydrocarbon), and NOx (nitrogen oxide) discharged from the engine 200, respectively. It is an example of “apparatus”. An air-fuel ratio sensor 221 is disposed upstream of the three-way catalyst 222 in the exhaust pipe 220. Air-fuel ratio sensor 221 is configured to be able to detect the air-fuel ratio of engine 200 based on the oxygen concentration in exhaust pipe 220. The air-fuel ratio sensor 221 is electrically connected to the ECU 100, and the detected air-fuel ratio is grasped by the ECU 100 constantly or at a constant or indefinite period.

  A water temperature sensor 223 for detecting a cooling water temperature Thw related to cooling water (LLC) circulated and supplied to cool the engine 200 is disposed in the water jacket in the cylinder block that houses the cylinder 201. Yes. The water temperature sensor 223 is electrically connected to the ECU 100, and the detected cooling water temperature Thw is grasped by the ECU 100 constantly or at a constant or indefinite period.

  Here, in the internal combustion engine according to the present invention, for example, for the purpose of preventing direct contact between physical or mechanical components in the internal combustion engine or preventing seizure of the components, for example, Discharge means that is temporarily stored in an oil pan or the like installed below a cylinder block that accommodates the cylinder 201, for example, lubricating oil such as engine oil can take various forms such as electric drive type or mechanical drive type, Alternatively, it is configured to be circulated and supplied, for example, in a circulation path that is physically or mechanically constructed in advance by the action of the circulation means as a concept that may appropriately include suction means such as an oil strainer.

  For example, an intake valve system and an exhaust valve system that drive the intake valve 211 and the exhaust valve 218 and can include, for example, an intake cam, an intake camshaft, an exhaust cam, and an exhaust camshaft 224 (all of which are omitted in FIG. 2). Is housed in a metal cylinder head located above the cylinder block. Engine oil is circulated and supplied to these intake valve system and exhaust valve system housed in the cylinder head so that the operation of each part is lubricated and seizure prevention is achieved. In the cylinder 201, for example, sliding between the crankshaft 205 and the connecting rod 204 accommodated in the crankcase and the piston 203, and between the piston 203 and the inner wall of the cylinder 201 (that is, the bore) is performed. In order to achieve smoothness, engine oil is circulated and supplied so that the operation is lubricated and each part is prevented from being seized.

  On the other hand, the engine oil circulated and supplied to each part of the engine 200 as described above is temporarily stored in an oil pan installed below the cylinder block. The oil pan is provided with a circulation device (not shown) including an electric oil pump as an electrically driven pump, and the engine oil stored in the oil pan is described above via a circulation supply path (not shown). It is configured to be able to circulate and supply various target parts. The electric oil pump is electrically connected to the ECU 100, and the driving state is controlled by the control of the ECU 100. The engine oil circulation mode is not limited to that of the present embodiment as long as the operation of each part in the engine 200 can be lubricated and seizure prevention can be achieved, and various modes may be adopted.

  Returning to FIG. 1, the torque converter 300 is a fluid transmission device connected to the rear stage of the crankshaft 205 described above in the engine 200. Torque converter 300 is configured to transmit the rotational power of engine 200 transmitted through crankshaft 205 to ECT 400. The detailed configuration of the torque converter 300 will be described later.

  The ECT 400 includes a plurality of hydraulic friction engagement devices driven by a hydraulic actuator (not shown) such as a clutch element, a brake element, and a one-way clutch element, and is an electronically controlled automatic transmission that is an example of a “transmission device” according to the present invention. Device. The ECT 400 is configured to be able to obtain a plurality of different gear ratios by changing the engagement state of each of these hydraulic friction engagement devices. The detailed configuration of the ECT 400 will be described later together with the torque converter 300 with reference to FIG.

  The vehicle 10 further includes a speed reduction mechanism 11, a left drive shaft SFL, a right drive shaft SFR, a left drive wheel FL, a right drive wheel FR, a shift lever 12, a shift position sensor 13, an accelerator opening sensor 14, and an accelerator pedal 15. .

  The reduction mechanism 11 is a gear device configured by various reduction gears including a differential gear connected to the output rotation shaft of the ECT 400. After the rotation speed of the output rotation shaft of the ECT 400 is reduced according to a specific reduction ratio, the left and right sides are reduced. It can be transmitted to the drive shaft.

  The left drive shaft SFL and the right drive shaft SFR are rotation shafts connected to the left drive wheel FL and the right drive wheel FR, respectively, and are configured to be connected to the speed reduction mechanism 11. Therefore, in the vehicle 10, the power generated from the engine 200 is transmitted to the left and right drive wheels via the crankshaft 205, the torque converter 300, the ECT 400, the speed reduction mechanism 11, and the left and right drive shafts. The torque converter 300, the ECT 400, the speed reduction mechanism 11, the left drive shaft SFL, and the right drive shaft SFR constitute a power train of the vehicle 10 as a whole.

  The shift lever 12 is a shifting operation means configured to be operated by a driver of the vehicle 10. In this embodiment, the shift lever 12 is provided with a total of seven types of shift positions: 1 range, 2 range, 3 range, D range, N range, R range, and P range. The control mode of the gear ratio of the ECT 400 changes according to the above.

  The shift position sensor 13 is a sensor configured to be able to detect the shift position of the shift lever 12. The shift position sensor 13 is electrically connected to the ECU 100, and the detected shift position is grasped by the ECU 100 constantly or at a constant or indefinite period. The ECU 100 is configured to control the ECT 400 according to the detected shift position.

  The accelerator opening sensor 14 is a sensor configured to be able to detect the accelerator opening that is the opening of the accelerator pedal 15 operated by the driver. The accelerator opening sensor 14 is electrically connected to the ECU 100, and the detected accelerator opening is grasped by the ECU 100 constantly or at a constant or indefinite period.

  The ECT drive unit 500 is configured to be able to drive the ECT 400 physically, mechanically, electrically, and magnetically. More specifically, the ECT drive unit 500 changes the engagement state of the plurality of friction engagement devices described above. It is the drive unit comprised so that it could be made to. The ECT drive unit 500 includes a plurality of linear solenoids and solenoids, each of which drives a hydraulic actuator that drives each of the hydraulic friction engagement devices of the ECT 400 described later.

  The hydraulic controller 600 performs each friction engagement in the ECT 400 by the excitation state control (for example, duty ratio control) of the linear solenoid and the excitation state control (for example, switching control between excitation and non-excitation) of the solenoid in the ECT drive unit 500 described above. The control unit is configured to be able to control the hydraulic pressure of the hydraulic actuator corresponding to the apparatus. The hydraulic controller 600 is electrically connected to the ECU 100, and its operation state is controlled to the upper level by the ECU 100.

  Next, detailed configurations of the torque converter 300 and the ECT 400 will be described with reference to FIG. FIG. 4 is a schematic configuration diagram conceptually showing the configurations of the torque converter 300 and the ECT 400. In the figure, the same reference numerals are given to the same portions as those in FIG. 1, and the description thereof will be omitted as appropriate.

  In FIG. 3, the torque converter 300 includes a pump impeller 310, a turbine runner 320, a stator 330, a one-way clutch 340, and a lock-up clutch 350.

  The pump impeller 310 is connected to the crankshaft 205 of the engine 200 and is configured to be rotatable in synchronization with the rotation of the crankshaft 205.

  The turbine runner 320 is opposed to the pump impeller 310 via an ATF (Automatic Transmission Fluid) and is connected to the input shaft 401 of the ECT 400. Accordingly, the rotational speed of the turbine runner 320 is equivalent to the rotational speed of the input shaft 401 of the ECT 400. The turbine rotation speed NT, which is the rotation speed of the turbine runner 320, is detected by a turbine rotation sensor (not shown) and is grasped by the ECU 100 electrically connected to the turbine rotation sensor constantly or at a constant or indefinite period. It is the composition which becomes.

  The stator 330 is connected to a housing (not shown) as a non-rotating member via a one-way clutch 340, and is configured to be able to change the direction of ATF returning from the turbine runner 320 to the pump impeller 310. It is.

  The lockup clutch 350 is a clutch configured to be able to directly transmit the rotational power transmitted from the crankshaft 205 to the input shaft 401 without passing through the torque converter 300 according to the engaged state.

  On the other hand, in FIG. 3, an ECT 400 is coaxially disposed on an input shaft 401, and a carrier and a ring gear are connected to each other to form a so-called CR-CR coupled planetary gear mechanism. A pair of first planetary gear mechanism 430 and second planetary gear mechanism 440, a pair of third planetary gear mechanisms 450 arranged coaxially with a counter shaft 402 parallel to the input shaft 401, and a shaft end of the counter shaft 402 And an output gear 403 that meshes with the speed reduction mechanism 11 described above.

  Each of the components of the first planetary gear mechanism 430, the second planetary gear mechanism 440, and the third planetary gear mechanism 450, that is, the carrier that rotatably supports the sun gear, the ring gear, and the planetary gear that meshes with the four gears C0. , C1, C2 and C3, and selectively connected to the non-rotating member housing by three brakes B1, B2 and B3, or mutually by two one-way clutches F1 and F2. It is configured to be engaged with the housing.

  Each of these clutches and brakes is a hydraulic friction engagement device whose engagement state is controlled by a hydraulic actuator, such as a multi-plate clutch or a band brake, and is controlled by the hydraulic controller 600 as described above. Drive control is performed by the ECT drive unit 500, and the hydraulic pressure that defines the engagement force changes.

  Under such a configuration, a pair of first planetary gear mechanism 430, second planetary gear mechanism 440, clutch C0, clutch C1, clutch C2, brake B1, brake B2, and one-way clutch arranged coaxially with input shaft 401. F1 constitutes a main transmission section 410 having four forward speeds and one reverse speed. Further, the auxiliary transmission unit 420 is configured by a set of planetary gear mechanisms 450, a clutch C3, a brake B3, and a one-way clutch F2 arranged on the counter shaft 402. The auxiliary transmission unit 420 realizes two forward speeds, so that the ECT 400 as a whole realizes five forward speeds.

<Operation of Embodiment>
<Operation of ECT400>
First, with reference to FIG. 5, the relationship between the engagement state of the hydraulic friction engagement device in the ECT 400 and the realized gear stage will be described. FIG. 5 is a table for explaining the correspondence between the engagement states of the hydraulic friction engagement devices in the ECT 400 and the shift speeds to be realized.

  In FIG. 5, the shift position selected by the shift lever 12 and the corresponding gear position are sequentially arranged in the vertical series, and the above-described hydraulic friction engagement devices are arranged in the horizontal series. ing. In FIG. 5, “◯” represents that it is engaged, and “X” represents that it is released. Further, “Δ” indicates that the engagement is performed only during driving.

  In FIG. 5, the R range (corresponding to the reverse gear), the P range and the N range (corresponding to the gear when the power is cut off), and the D range (corresponding to the forward gear (5)). Only the engagement state corresponding to is shown. That is, the engagement state corresponding to the 1st range, the 2nd range, and the 3rd range is equivalent to the engagement state corresponding to the 1st, 2nd, and 3rd shift speeds realized in the D range, and the illustration is omitted. Yes.

  As shown in the figure, in the ECT 400, when the shift position is in the D range, five forward shift speeds corresponding to “1st”, “2nd”, “3rd”, “4th”, and “5th” are realized. The The speed ratios of these forward shift speeds decrease in the order of “1st”, “2nd”, “3rd”, “4th”, and “5th”. That is, “1st” is the maximum and “5th” is the minimum. When the shift position of the shift lever 12 is in the D range, the gear position is automatically switched based on the shift map stored in the ROM, for example, under the control of the ECU 100. Therefore, in the ECT 400, it is constantly grasped by the ECU 100 which gear stage is selected at that time.

<Overview of fuel dilution and air-fuel ratio F / B control>
In the engine 200, fuel is directly injected into the cylinder 201 through the direct injection injector 212. In this way, when the fuel is directly injected, for example, compared with the case where the fuel is injected into the intake port 210, the amount of fuel provided for combustion is more accurate in that the fuel does not adhere to the intake port 210. There is an advantage that the air-fuel ratio control can be performed more accurately. Further, since the inside of the cylinder can be relatively cooled by the latent heat of vaporization of the direct injection fuel, there is an advantage that the charging efficiency of intake air is further improved.

  On the other hand, in such a direct injection type engine, the injected fuel may adhere to the bore of the cylinder 201. In particular, this tendency is conspicuous when an attempt is made to shift the fuel injection position upward of the cylinder 201 in order to form a more favorable air-fuel mixture in order to improve the fuel combustion efficiency. Thus, the fuel adhering to the bore of the cylinder 201 is not shown in the reciprocating motion of the piston 203 and also remains in the bore as described above (that is, a minute amount formed to smooth the reciprocating motion of the piston 203). The fuel is diluted by diluting the engine oil by being taken in by a piston ring that cannot be completely wiped off by a piston ring due to a clear clearance.

  Here, in particular, when the fuel dilution occurs, the fuel taken into the engine oil, that is, the diluted fuel, evaporates rapidly as the temperature of the engine oil rises. The evaporated diluted fuel is returned to the intake system through various control valves such as PCV or various known recirculation mechanisms so as to be used for combustion in the cylinder 201 again. At this time, the amount of the diluted fuel that is returned to the intake system is kept substantially constant according to the degree of fuel dilution.

  In the vehicle 10, the ECU 100 executes air-fuel ratio F / B control that corrects the injection amount based on the air-fuel ratio acquired via the air-fuel ratio sensor 221. In this air-fuel ratio F / B control, basically, the injection amount decreases if the air-fuel ratio detected by the air-fuel ratio sensor 221 is rich with respect to the target air-fuel ratio, and should be lean with respect to the target air-fuel ratio. The injection amount is corrected so that the injection amount increases.

  On the other hand, the correction value used for correcting the injection amount is learned intermittently at a constant or indefinite period when the engine 200 is warmed up. The latest learning value efgaf in the learning process is stored in the RAM of the ECU 100 in an updatable manner.

  In the present embodiment, the fuel injection amount is obtained by multiplying the basic injection amount set for each operation region of the engine 200 defined by the engine speed NE and the load (or load factor) by the learning value efgaf. Is calculated by However, the calculation form of the injection amount is not limited to this, and for example, various known aspects may be adopted. For example, the basic injection amount may be further corrected based on the coolant temperature Thw of the engine 200 at that time, the intake air temperature, the engine oil temperature, the catalyst bed temperature, the outside air temperature, or the like.

  Here, the relationship between the learning value and the load of the engine 200 will be described with reference to FIG. FIG. 6 is a graph showing the relationship between the correction value learning value efgaf and the learning load region.

  In FIG. 6, the learning value efgaf is represented on the vertical axis. In FIG. 6, the learning value efgaf is shown with an upper limit of 100 (%) for convenience, but the range that can be taken is not limited to this. On the other hand, the horizontal axis indicates a learning load area. The learning load region is a load region of the engine 200 where correction value learning is performed, and is divided into five regions in this embodiment. That is, learning load region 0 (hereinafter referred to as “region 0” as appropriate), learning load region 1 (similarly “region 1”),..., Learning load region 4 (similarly “ Region 4 ").

  As is apparent from FIG. 6, the learning value efgaf is shifted to the decreasing side as the light load side is reached, that is, the injection amount is corrected to decrease as the light load side. During the warm period when the correction value is learned, the aforementioned diluted fuel has already evaporated, and the combustion includes this evaporated fuel in addition to the fuel injected from the direct injection injector 212. On the other hand, since the absolute value of the injection amount becomes smaller at the light load side, the degree of occupation of the evaporated diluted fuel with respect to the entire injection amount inevitably increases if the supply amount of the evaporated diluted fuel is substantially constant. For this reason, the learning value efgaf of the correction value is shifted toward the side where the injection amount is further decreased as the load becomes lighter. This tendency increases as the degree of fuel dilution increases. FIG. 6 shows characteristics of the learned value efgaf corresponding to three different types of fuel dilution levels (ie, high dilution (see solid line), medium dilution (see broken line), and low dilution (see dashed line)). Is shown. Such a plurality of characteristics are shown for convenience, and when learning correction values in this embodiment, a plurality of learning values corresponding to the degree of fuel dilution are obtained. Instead, one learning value is always obtained according to the degree of fuel dilution at that time.

<Details of catalyst rapid warm-up control>
In the vehicle 10, the rapid catalyst warm-up control is executed by the ECU 100 in order to warm up the three-way catalyst 222 early in order to reduce the emission in the on mode or the off mode. Here, the details of the catalyst rapid warm-up control will be described with reference to FIG. FIG. 7 is a flowchart of the catalyst rapid warm-up control.

  In FIG. 7, the ECU 100 determines whether or not the catalyst rapid warm-up control execution permission flag FG is in an ON state indicating that the execution of the catalyst rapid warm-up control should be permitted (step S101). Here, in this embodiment, the catalyst rapid warm-up control is performed when the vehicle 10 is stopped and the coolant temperature Thw is lower than the warm-up completion temperature (set to 75 ° C. in the present embodiment). Executed. The state of the engine 200 when the coolant temperature Thw is lower than the warm-up completion temperature is an example of “the catalyst device is in an unwarmed state” according to the present invention. The ECU 100 permits the execution of the catalyst rapid warm-up control based on whether the coolant temperature Thw detected by the water temperature sensor 223 is equal to or higher than the warm-up completion temperature or the vehicle 10 is traveling. If it is in the off state indicating that it is not performed (step S101: NO), the process according to step S101 is repeated to control the process substantially to the standby state and the execution permission flag FG is in the on state (step S101: YES), it is determined whether or not the shift position of the shift lever 12 corresponds to a predetermined travel range (step S102).

  Here, the “traveling range” refers to a shift position at which the shift stage of the ECT 400 can be controlled to the shift stage for traveling, and refers to the above-described 1 to 3 range, R range, and D range. The ECU 100 determines whether or not the travel range is selected based on whether or not the shift position detected by the shift position sensor 13 corresponds to any of these.

  When the travel range is not selected (step S102: NO), that is, when the N range or the P range is selected, the ECU 100 further sets the coolant temperature Thw to the reference value ThwL (that is, the “reference value according to the present invention”). It is determined whether or not (step S103). Here, the “reference value ThwL” is a temperature at which whether or not the load needs to be reduced in order to reduce the engine speed NE is switched, and is set to 46 ° C. in the present embodiment. When the coolant temperature Thw is lower than the reference value ThwL (step S103: YES), the ECU 100 selects a high load region learning value (step S105).

  On the other hand, if it is determined that the travel range is selected in the determination process according to step S102 (step S102: YES), or if the coolant temperature Thw is equal to or higher than the reference value ThwL (step S103: YES), the ECU 100 Selects a light load region learning value (that is, an example of “a correction value corresponding to a predetermined light load region” according to the present invention) (step S104). The case where the coolant temperature Thw is equal to or higher than the reference value ThwL corresponds to the case where the coolant temperature Thw is 46 ° C. or higher and lower than 75 ° C. in view of the execution conditions of the catalyst rapid warm-up control described above. Here, the high load area learning value selected in the process according to step S105 is a learning value corresponding to the area 4 in FIG. 6, and the light negative area learning value selected in the process according to step S106 is: Similarly, it is assumed that the learning value corresponds to the region 1.

  Note that the high load region learning value and the light load region learning value are not limited to those exemplified here, but are a learning value that is at least qualitatively insensitive to diluted fuel and a learning value that is easily influenced by diluted fuel. As far as free. That is, referring to FIG. 6, the high load region learning value may be the learning value of region 3, and the light load region learning value may be the learning value of region 0. Further, these may be uniquely selected according to the load state of the internal combustion engine in the catalyst rapid warm-up control.

  Here, if supplemented with reference to FIG. 6, the high load region learning value (here, the learning value of region 4) is not easily affected by the evaporated diluted fuel, and therefore, usually in the catalyst rapid warm-up control. This high load area learning value is preferably used. However, when the traveling range is selected as the shift position, in order to stop the vehicle 10, it is necessary to apply a certain amount of braking force to at least the drive wheels from the braking device provided in the vehicle 10. The brake negative pressure that influences the braking force is created by using the negative pressure of the intake pipe 207, and in order to ensure a corresponding brake negative pressure, it is necessary to reduce the throttle opening. If the throttle valve 208 is closed, the intake air amount, that is, the load is uniquely reduced. Therefore, in a situation where the travel range is selected, the light load region learned value must be used. Further, when the cooling water temperature of the engine 200 is in the above-described temperature range, the combustion performance of the engine 200 is higher than the temperature range below the reference value, so that the engine speed tends to increase accordingly. It is desirable that the engine speed NE during the execution of the catalyst rapid warm-up control is substantially constant for the purpose of reducing the uncomfortable feeling given to the driver. In this case, the engine speed is necessarily reduced by reducing the throttle valve opening. It needs to be lowered. For this reason, even when the cooling water temperature is in this range, the light load region learned value must be used.

  When the learning value is selected in the process related to step S104 or step S105, ECU 100 sets the target air-fuel ratio A / Ftag (step S106). In the catalyst rapid warm-up control, lean combustion control with stratified combustion of fuel is executed, so that the target air-fuel ratio A / Ftag is leaner than the theoretical air-fuel ratio (14.3 in this embodiment). Is set.

  When the target air-fuel ratio A / Ftag is set, the ECU 100 next sets the fuel injection timing (step S107). In the catalyst rapid warm-up control, the injection timing is retarded to increase the exhaust gas temperature. Therefore, the ECU 100 normally retards the injection timing set in the suction process until the middle of the compression process (which may be the initial stage or the final stage) in the catalyst rapid warm-up control.

  When the injection timing is set, the ECU 100 further sets the injection amount (step S108). The injection amount is set based on the load, that is, the intake air amount, the target air-fuel ratio A / Ftag, and the learned value of the injection amount correction value. More specifically, the basic injection amount is calculated according to the load, and the basic injection amount is corrected according to the target air-fuel ratio A / Ftag (the basic injection amount is a value corresponding to the theoretical air-fuel ratio). And this value is further multiplied by the learning value obtained in the processing according to step S104 or step S105.

  When the injection amount is set, ECU 100 further sets the ignition timing (step S109). In the catalyst rapid warm-up control, the ignition timing is retarded. Therefore, the ECU 100 sets the ignition timing by retarding the reference ignition timing set in advance by a constant amount or a constant rate.

  When the injection timing, the injection amount, and the ignition timing are set, ECU 100 controls engine 200 according to the set operating conditions (step S110). If the process which concerns on step S110 is performed, a process will be returned to step S101 and a series of processes will be repeated.

  Here, the stratified combustion is realized in the engine 200 by delaying the injection timing until the compression process. That is, the fuel injected from the direct injection injector 212 is unevenly distributed around the spark plug of the ignition device 202. Further, since the ignition timing is retarded, the fuel is exhausted in the exhaust process before the combustion is completed within the combustion process. For this reason, higher temperature exhaust gas is supplied to the three-way catalyst 222, and the temperature rise is promoted. Further, the air-fuel ratio is lean as a whole, and the fuel consumption rate is relatively small. In other words, in the rapid catalyst warm-up control, the temperature of the three-way catalyst 222 is accelerated quickly, and the emission is reduced.

<Overview of lower limit guard value setting process>
For example, in the rapid catalyst warm-up control when a predetermined condition is satisfied, for example, when the shift position of the shift lever 12 is in the D range or the cooling water temperature Thw is equal to or higher than the reference value ThwL and lower than the warm-up completion temperature. As described above, the injection amount is controlled using the light load region learning value. Here, as is apparent from FIG. 6, the learning value efgaf in the light load region (here, region 1) is influenced by the evaporated diluted fuel, and is compared with the high load region learning value. It changes to the side to reduce the weight. That is, the fuel injected from the direct injection injector 212 inevitably decreases in a situation where the light load region learning value is used.

  However, during the period in which the rapid catalyst warm-up control is executed, for example, during cold start, the engine oil temperature is low, so that it is difficult for the diluted fuel to actually evaporate. Therefore, if the injection amount during the rapid warm-up of the catalyst is determined using the light load region learning value, the amount of fuel injected may be reduced from the required amount in some cases, and the air-fuel ratio will be leaner than the target air-fuel ratio. It can lead to misfire. Therefore, in the vehicle 10, the lower limit guard value setting process is executed by the ECU 100, and the occurrence of problems due to the use of such a light load region learning value is avoided.

  Here, the details of the lower limit guard value setting process will be described with reference to FIG. FIG. 8 is a flowchart of the lower limit guard value setting process.

  In FIG. 8, the ECU 100 determines whether or not the catalyst rapid warm-up control using the learned value in the light load region is being executed (step S201). When the catalyst rapid warm-up control itself is not executed, or when the catalyst rapid warm-up control using the high load region learning value is performed (step S201: NO), the ECU 100 repeats the process according to step S201. Execute to control the process substantially to the standby state.

  On the other hand, when the catalyst rapid warm-up control using the light load region learning value is being executed (step S201: YES), the ECU 100 subtracts the light load region learning value efgafL from the judgment reference value efgafH of the high load region learning value. Then, it is determined whether or not the learned value difference Δefgaf is less than the value obtained by adding the margin α to the low temperature increase value K (step S202).

  Here, the “high load region learning value judgment reference value efgafH” is different from the above-described high load region learning value (that is, the learning value of region 4) and corresponds to the high load region (that is, diluted fuel). It is an addition average value of learning values of each of the region 3 and the region 4 (corresponding to a load region that is not easily affected), and is an example of “a correction value corresponding to a high load region” according to the present invention. By taking the addition average in this way, problems that may occur when the learning value is different from the original value due to erroneous learning of the correction value are alleviated. Note that the judgment reference value efgafH of the high load region learning value that constitutes the learning value difference Δefgaf is low enough that, for example, the possibility of mislearning is practically negligible, or mislearning has occurred. Particularly in a situation where it can be determined that the degree is negligible in practice, the above-described high load region learning value (here, the learning value of region 4) itself may be used.

  Further, the low temperature increase value K is calculated according to the elapsed time after the start of the engine 200 and the cooling water temperature Thw (including a mode selectively acquired from a map or the like), and the non-execution period of the catalyst rapid warm-up control Is a coefficient that should be multiplied by the basic injection amount in order to compensate for fuel wall adhesion and combustion performance degradation when the engine is not warmed up. That is, in the present embodiment, the low temperature increase value K is assumed to be a correction coefficient of the same type as the learning value efgaf of the injection amount. The method for determining the low temperature increase value related to the low temperature increase of the fuel injection amount (also referred to as warm-up increase or post-start-up increase, etc.) can use various known modes. Omitted.

  On the other hand, the margin α to be added to the low temperature increase value K is a suitable value set in advance experimentally, empirically, theoretically, or based on simulation or the like. This value correlates with the initial value of the deviation edlfggd. In addition, the meaning which the process which concerns on step S202 has is mentioned later.

  When the learned value difference Δefgaf is equal to or greater than K + α (step S202: NO), the ECU 100 controls the execution permission flag FG for the catalyst rapid warm-up control to be in an off state (step S203), and returns the process to step S201. When the execution permission flag FG is set to the OFF state, the determination processing related to step S101 in the catalyst rapid warm-up control shown in FIG. 7 is “NO”, and if the catalyst rapid warm-up control is being executed, Execution is forcibly terminated (however, the forcible termination process step is omitted in FIG. 7). Accordingly, returning to FIG. 8, the determination processing in step S201 is “NO”, and the lower limit guard value setting processing is also substantially controlled to the standby state.

  Here, the forced termination of the catalyst rapid warm-up control based on the low temperature increase value will be described with reference to FIG. FIG. 9 is a timing chart in the execution process of the lower limit guard value setting process.

  In FIG. 9, the horizontal axis represents the time in common, and the vertical axis represents the low temperature increase value K, the state of the neutral switch SW, and the state of the execution permission flag FG in order from the top. Here, the neutral SW is a switch that is turned on when the shift position of the shift lever 12 is in the N range, and is a kind of flag.

  It is assumed that the shift position changes from the N range to the D range, for example, at time T1 during the execution of the catalyst rapid warm-up control. At this time, the neutral SW is switched from the on state to the off state. By such switching of the shift position, the learning value used for correcting the injection amount in the catalyst rapid warm-up control is changed from the high load region learning value (in this embodiment, the learning value of region 4) to the light load at this time. It switches to the area learning value (in this embodiment, the learning value of area 1).

  On the other hand, the low temperature increase value K gradually decreases according to the elapsed time after the start of the engine 200 and the cooling water temperature Thw from before the time T1 (that is, corresponding to a decrease in the injection amount), and a light load It is assumed that, at time T2 in the process of performing the catalyst rapid warm-up control using the region learning value, the value A is taken and the value obtained by adding the margin α to the value A is equal to or less than the learning value difference Δefgaf. In this case, the execution permission flag FG changes from the on state to permit the execution of the catalyst rapid warm-up control to the off state to not permit at the time T2.

  Returning to FIG. 8, when the learned value difference Δefgaf is less than K + α (step S202: YES), the ECU 100 determines whether it is the initial setting timing of the lower limit guard value (step S204). Here, the “initial setting timing” refers to the setting timing of the lower limit guard value that is first visited in the lower limit guard value setting process executed as a loop process. However, if the execution of the catalyst rapid warm-up control is temporarily interrupted, the setting history of the lower limit guard value (or the value of the counter that counts the number of times the lower limit guard value is set) is reset. Then, the process related to step S204 that is first visited thereafter is treated as the initial setting timing.

When it is the initial setting timing of the lower limit guard value (step S204: YES), the ECU 100 sets the initial value of the guard setting deviation edlfggd (step S205). Here, the guard setting deviation edlfggd is a limit value for limiting the reflection of the light load region learning value efgafL with respect to the injection amount. In the present embodiment, the initial value is 0.05 (that is, 5%). Is set to When the initial value of the guard setting deviation edlfggd is set, the ECU 100 calculates the lower limit guard value efgafxgd of the learning value according to the following equation (1) (step S208).
efgafxgd = efgafH-edlfggd (1)
As described above, since the initial value of the guard setting deviation edlfggd is 0.05, the correction value of the injection amount in the catalyst rapid warm-up control becomes the high load region learning value by applying the equation (1). It is limited to 95% (that is, minus 5%) of the criterion value. Supplementing with reference to FIG. 6, it is assumed that the average value of the learning values of the region 3 and the region 4 (that is, the judgment reference value efgafH of the high load region learning value) is approximately 100%. The learning value of the region 1 corresponding to the large degree of dilution) is originally about 92%, but its reflection is limited with “100−5 = 95 (%)” as a lower limit. That is, the injection amount is set in a range of 95% or more of the basic injection amount. This is the same even if the learning value of the area 0 instead of the area 1 is used as the light load area learning value, and in that case, the degree of restriction of reflection becomes larger. When the lower limit guard value efgafxgd of the light load region learned value is calculated in this way, when the learned value is reflected in the determination of the injection amount in the process related to step S108 in the catalyst rapid warm-up control shown in FIG. The lower limit guard value efgafxgd serves as a lower limit guard for the injection amount.

  When the lower limit guard value efgafxgd of the light load region learning value is calculated, the ECU 100 returns the process to step S204. In this case, it is not the initial setting timing (step S204: NO), and the process proceeds to step S206. In the process related to step S206, it is determined whether or not the air-fuel ratio detected by the air-fuel ratio sensor 221 is less than the theoretical air-fuel ratio (here, 14.3).

  Here, when the change of the learning value in the light load region to the decrease side (the side to decrease the injection amount) is caused by evaporation of the diluted fuel, the execution period of the catalyst rapid warm-up control in which the diluted fuel hardly evaporates. The above-described limitation of the reflection of the learning value in the engine is significant, and the air-fuel ratio preferably converges in the vicinity of the original target air-fuel ratio A / Ftag (lean-side air-fuel ratio) for the catalyst rapid warm-up control. However, when such a shift in the learning value to the decrease side is caused by a factor unrelated to the diluted fuel, by limiting the reflection of the learning value in the light load region, at least some of the injection amount that should be originally reduced is reduced. The fuel will be injected without being significantly reduced.

  In this case, the injection amount becomes excessive with respect to the injection amount corresponding to the target air-fuel ratio A / Ftag, and the air-fuel ratio gradually decreases (that is, shifts to the rich side). In addition, the air-fuel ratio F / B control is prohibited during the execution of the catalyst rapid warm-up control (the air-fuel ratio sensor 221 is in spite of the fact that the air-fuel ratio around the spark plug becomes too rich and misfires. Since the air-fuel ratio leanness is detected by being affected by the remaining oxygen due to misfire, the reliability of the detected air-fuel ratio is reduced), so the air-fuel ratio continues to decrease. As a result, the deterioration of the emission due to the rich air-fuel ratio becomes obvious, and there may be a problem that the emission deteriorates eventually.

  On the other hand, if it is detected that the air-fuel ratio is rich, at least the oxygen concentration has decreased, so it is reasonable to determine that the fuel is being supplied excessively. That is, during the catalyst rapid warm-up control, the reliability of the lean air-fuel ratio detection result is not ensured, but the rich air-fuel ratio detection result is highly reliable. Therefore, when the air-fuel ratio is less than the theoretical air-fuel ratio (step S206: YES), the ECU 100 gradually increases the guard setting deviation edlfggd according to the following equation (2) (step S207).

edlfggd (i) = edlfggd (i−1) +0.0004 (2)
Here, (i) indicates the latest setting timing, and (i-1) indicates the previous setting timing. That is, by applying the expression (2), the guard setting deviation edlfggd is increased by 0.04% from the previous value every time step S207 is visited. When the guard setting deviation edlfggd is gradually increased as described above, the process proceeds to step S208, and the calculation according to the above (1) is executed based on the gradually increased guard setting deviation edlfggd. That is, the lower limit guard value efgafxgd of the light load region learning value decreases by 0.04% every time step S207 is performed.

  In the process in which such processing is repeated as appropriate, the air-fuel ratio increases in response to an increase in the amount of reduction in the injection amount. As a result, when the air-fuel ratio becomes equal to or higher than the stoichiometric air-fuel ratio (step S206: NO), the process is returned to step S201, and a series of processes is repeated. In other words, in this case, ideally, the loop processing returning to step S201 through steps S201, S202, S204, and S206 in order is repeated until the execution of the catalyst rapid warm-up control is completed.

  Here, in particular, in the present embodiment, the value of the margin α to be added to the low temperature increase value K described above is set equal to the initial value (ie, 0.05) of the guard setting deviation edlfggd. That is, the state where the learning value difference Δefgaf is equal to or greater than K + α means that the fuel that becomes excessive due to the application of the lower limit guard value when the light load region learning value is shifted to the decrease side for reasons other than diluted fuel. The amount is larger than when the low temperature increase value is applied, i.e., when the low temperature increase control is performed using the low temperature increase value, it can be determined that the emission deterioration is suppressed. is there. Here, it can be determined to some extent on the basis of the air-fuel ratio as described above whether or not the shift to the decrease side of the light load region learning value actually occurs other than the diluted fuel, and in step S206. The enrichment of the air-fuel ratio due to excessive fuel is compensated by gradually increasing the guard setting deviation edlfggd. However, in practice, it takes a certain amount of time until the air-fuel ratio sensor 221 is in an active state (a state in which a correct output signal corresponding to the oxygen concentration can be output), and the air-fuel ratio sensor 221 becomes active. Until the lower limit guard value is reduced, the emission worsens that cannot be overlooked in practice. Therefore, when the learning value difference Δefgaf is equal to or greater than K + α, the execution of the catalyst rapid warm-up control is prohibited from the viewpoint of preventing excessive deterioration of the emission.

  Here, the control process of the air-fuel ratio by the lower limit guard setting process will be described with reference to FIG. FIG. 10 is another timing chart in the process of executing the lower limit guard setting process. In the figure, the same reference numerals are given to the same portions as those in FIG. 9, and the description thereof will be omitted as appropriate.

  In FIG. 10, in the series of the vertical axis, the state of the neutral SW, the air-fuel ratio A / F, the lower limit guard value efgafxgd, and the learning load region are represented in order from the top.

  Assume that at time T3, the neutral SW is switched from the on state to the off state, and the learning load region is switched from the region 4 (ie, the high load region) to the region 1 (ie, the light load region). At this time, it is assumed that the lower limit guard value efgafxgd is set to efgafxgd0 obtained by reducing the above-described determination reference value (the average value of the learning values of the region 3 and the region 4) by 5%. As a comparative example, the learning value of the correction value of the injection amount when the lower limit guard setting process is not performed is as shown by a broken line in the figure, and efgafxgd1 (efgafxgd1 < efgafxgd0).

  On the other hand, when the shift of the light load region learning value to the decrease side is irrelevant to the diluted fuel, the air-fuel ratio becomes the target air-fuel ratio A / Ftag that is the target value of the original catalyst rapid warm-up control from time T3. Begins to decline. Thus, in the process of decreasing the air-fuel ratio, the air-fuel ratio becomes less than the theoretical air-fuel ratio 14.3, but at that time, the air-fuel ratio sensor 221 is still inactive and the air-fuel ratio continues to decrease. Further, it is assumed that the air-fuel ratio sensor 221 becomes active at time T4. At this time, if the detected air-fuel ratio is A / F0 (A / F0 <14.3), the lower limit guard value efgafxgd gradually decreases due to the gradual increase of the guard setting deviation edlfggd.

  In the process of gradual reduction, the air-fuel ratio starts changing to the lean side. When the stoichiometric air-fuel ratio becomes 14.3 or higher at time T5, the gradual decrease process of the lower limit guard value efgafxgd ends, and the lower limit guard value efgafxgd converges to the illustrated efgafxgd2 (efgafxgd1 <efgafxgd2 <efgafxgd0).

  As described above, according to the lower limit guard setting process according to the present embodiment, basically, the learning value of the correction value of the injection amount corresponding to the light load region (the light load region learning value in the present embodiment) is used. When the catalyst rapid warm-up control is performed, the reflection of the learning value corresponding to the light load region is based on the learning value corresponding to the high load region (in this embodiment, the criterion value of the high load region learning value). (In this embodiment, 95% is set as the lower limit), and leaning of the air-fuel ratio with respect to the target air-fuel ratio due to non-evaporation of diluted fuel is prevented. On the other hand, regarding the enrichment of the air-fuel ratio that occurs when the learning value corresponding to the light load region is shifted to the decrease side for reasons other than diluted fuel, the lower limit guard value efgafxgd is gradually decreased by gradually increasing the guard setting deviation edlfggd As a result, the air-fuel ratio is made lean and the air-fuel ratio converges to the vicinity of the theoretical air-fuel ratio quickly and accurately. Therefore, a decrease in the accuracy of the air-fuel ratio in the catalyst rapid warm-up control is suppressed, and the deterioration of emissions during the execution period of the catalyst rapid warm-up control is suppressed.

  In this embodiment, the light load region learning value is a learning value corresponding to region 1, but the “light load region” according to the present invention is reflected in the injection amount without limiting the learning value. In this case, the leaning of the air-fuel ratio due to the fact that the diluted fuel does not evaporate is manifested as a problem that cannot be overlooked in practice, for example, experimentally, empirically, theoretically or based on simulation This is a defined load region, and the specific load is different for each internal combustion engine. Accordingly, the determination as to whether or not the light load region is applicable to the present invention is, for example, a high load region (even if the learning value is reflected without limiting, leaning of the air-fuel ratio can be at least substantially ignored. For example, the deviation may be performed on the basis of whether or not the deviation exceeds a threshold. At this time, the threshold value used as a determination criterion may be stored in advance as a fixed value in a ROM or the like, or may be calculated specifically for each case.

  In this embodiment, the gradual increase rate of the guard setting deviation edlfggd is 0.04% for each set timing. However, this value is only an example, and if the gradual increase rate is set relatively large, The learning value is reflected relatively large in the injection amount, and conversely, if the gradually increasing rate is set relatively small, the gradually decreasing rate of the learning value becomes slow. Therefore, the gradually increasing rate can be used for the specification or destination of the vehicle 10, for example. Depending on the required performance of the engine 200 or the like, it may be set individually and specifically.

  In the present embodiment, the value of the margin α to be added to the low temperature increase value is equal to the initial value of the guard setting deviation edlfggd used for calculating the lower limit guard value of the light load region learning value. However, the values may be different from each other.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification. The control device is also included in the technical scope of the present invention.

1 is a schematic configuration diagram conceptually and schematically showing a main configuration of a vehicle according to an embodiment of the present invention. It is a schematic diagram of the engine with which the vehicle of FIG. 1 is equipped. FIG. 3 is a schematic configuration diagram conceptually showing a configuration of a high-pressure pump provided in the engine of FIG. 2. It is a schematic block diagram which represents notionally the structure of a torque converter and ECT. It is a table | surface explaining the corresponding | compatible relationship between the engagement state of each hydraulic friction engagement apparatus in ECT, and the implement | achieved gear stage. It is a graph showing the relationship between the learning value of the correction value of injection quantity, and the learning load area | region. It is a flowchart of the catalyst rapid warm-up control executed by the ECU. It is a flowchart of the lower limit guard value setting process performed by ECU. It is a flowchart in the execution process of a lower limit guard setting process. It is another flowchart in the execution process of a lower limit guard setting process.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Vehicle, 12 ... Shift lever, 13 ... Shift position sensor, 100 ... ECU, 200 ... Engine, 201 ... Cylinder, 202 ... Ignition device, 203 ... Piston, 208 ... Throttle valve, 212 ... Direct injection injector, 300 ... Torque Converter, 400 ... ECT.

Claims (9)

An injection control device for an internal combustion engine, provided in a vehicle, having a catalyst device and injection means capable of injecting fuel into a cylinder,
One correction value selected according to the load of the internal combustion engine from among a plurality of correction values to be reflected in the fuel injection amount learned at least for each load region of the internal combustion engine based on the air-fuel ratio. Determining means for determining the injection amount based on;
Control means for controlling the injection means so that the fuel corresponding to the determined injection amount is injected;
Execution means for performing catalyst rapid warm-up control including stratified combustion of the fuel under predetermined conditions including at least that the catalyst device is in an unwarmed state;
When the catalyst rapid warm-up control is executed when the injection amount is determined based on the correction value corresponding to a predetermined light load region, the correction value corresponding to the light load region to the injection amount An injection control device for an internal combustion engine, comprising: limiting means for limiting reflection of the internal combustion engine. The vehicle has an input shaft connected to the engine output shaft of the internal combustion engine and an output shaft connected to the axle, and the rotational speed of the input shaft and the output shaft when a predetermined traveling range is selected. A transmission device capable of automatically switching the ratio among a plurality of rotation speed ratios set in advance;
The limiting means is the case where the injection amount is determined based on the correction value corresponding to the light load region, the travel range is selected, or the cooling water temperature of the internal combustion engine is equal to or higher than a reference value. The injection control device for an internal combustion engine according to claim 1, wherein reflection of a correction value corresponding to a light load region is limited. The limiting means limits the reflection of the correction value corresponding to the light load region based on the correction value corresponding to the high load region set on the higher load side than the light load region. The injection control device for an internal combustion engine according to claim 1 or 2. The correction value corresponding to the high load region includes a plurality of load regions corresponding to a plurality of load regions including the load region on the highest load side of the correction values and the load region adjacent to the load region on the highest load side. The injection control device for an internal combustion engine according to claim 3, wherein the correction value is an average value. The correction value is reflected in the injection amount such that the magnitude corresponds to the magnitude of the injection amount,
The restriction means reflects the correction value corresponding to the light load region to the injection amount within a range equal to or higher than a lower limit guard value calculated based on the correction value corresponding to the high load region. Item 5. The injection control device for an internal combustion engine according to Item 3 or 4. When the deviation between the correction value corresponding to the light load region and the correction value corresponding to the high load region is greater than or equal to a predetermined value, the injection amount is determined based on the correction value corresponding to the light load region The injection control device for an internal combustion engine according to any one of claims 3 to 5, further comprising prohibiting means for prohibiting execution of the rapid catalyst warm-up control. The predetermined value of the deviation is set based on an increase value of the injection amount in a period in which the internal combustion engine is in an unwarmed state and the catalyst rapid warm-up control is not executed. An injection control device for an internal combustion engine as described. Further comprising specifying means for specifying the air-fuel ratio;
The said restriction | limiting means eases the degree which restrict | limits reflection of the correction value corresponding to the said light load area | region, when the specified air fuel ratio is less than predetermined value. An injection control device for an internal combustion engine according to claim 1. The injection control for an internal combustion engine according to claim 8, wherein the limiting means relaxes the degree of limiting the reflection of the correction value corresponding to the light load region until the air-fuel ratio becomes equal to or greater than the predetermined value. apparatus.

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