JP2011196289A - Exhaust emission control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust emission control device achieving early completion of catalyst warming-up while suppressing deterioration of fuel economy.SOLUTION: This exhaust emission control device includes: an adsorbent adsorbing HC in exhaust gas when the temperature of the adsorbent is below emission temperature and discharging the adsorbed HC when the temperature of the adsorbent reaches a temperature higher than the emission temperature; a catalyst oxidizing the HC discharged from the adsorbent when the temperature of the catalyst reaches a temperature higher than activation temperature; and a heat recovery device which is arranged upstream of the adsorbent and which recovers heat from exhaust gas by performing heat exchange with exhaust gas. In a warm-up request state with the temperature of the adsorbent being below the emission temperature and the temperature of the catalyst being below the activation temperature, heat-recovery reduction control is performed so that an amount of heat recovered by the heat recovery device is reduced (S13), engine-output increase control is performed so that the output of an internal combustion engine is increased (S18), and output-power increase control (drive load increase control) is performed (S18).

Description

  The present invention relates to an exhaust gas purification apparatus that adsorbs a specific component in exhaust gas of an internal combustion engine with an adsorbent.

  The adsorbent that adsorbs a specific component (for example, HC) in the exhaust gas of the internal combustion engine adsorbs HC when the adsorbent temperature is lower than the release temperature T1, and releases adsorbed HC when the adsorbent temperature is equal to or higher than the release temperature T1. The oxidation catalyst that oxidizes HC released from the adsorbent is activated and becomes oxidizable when the catalyst temperature is equal to or higher than the activation temperature T2. The activation temperature T2 is generally higher than the discharge temperature T1 (T2> T1). In short, HC is adsorbed by the adsorbent until the temperature of the oxidation catalyst reaches the activation temperature T2.

  By the way, at the time of cold start of the internal combustion engine, control for retarding the ignition timing (ignition retarding control) so as to raise the catalyst temperature to the activation temperature T2 at an early stage is disclosed in Patent Documents 1 and 2 and the like. Yes. However, if ignition retard control is performed immediately after the start of the internal combustion engine, the adsorbent temperature becomes equal to or higher than the release temperature T1 in a state where the adsorbed HC has not reached the saturation amount, and the adsorbing capacity by the adsorbent is sufficiently exhibited. Disappear. Therefore, in this type of exhaust gas purifying apparatus, ignition retard control is started from the time when the adsorbent temperature reaches the discharge temperature T1. Thereby, the catalyst warm-up is completed early while sufficiently increasing the amount of adsorption by the adsorbent.

JP 2004-116370 A JP 2001-164930 A

  However, in the control described in Patent Document 1 described above, since the catalyst is warmed up by retarding the ignition timing, fuel consumption is deteriorated by retarding the ignition. This problem is not limited to the case where HC in the exhaust gas is adsorbed and oxidized, but can also occur in the same manner when NOx is adsorbed and reduced, for example.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an exhaust gas purifying apparatus that achieves early completion of catalyst warm-up while suppressing deterioration in fuel consumption.

  Hereinafter, means for solving the above-described problems and the operation and effects thereof will be described.

  In the first aspect of the invention, the adsorbent that adsorbs the specific component in the exhaust gas of the internal combustion engine when its own temperature is lower than the release temperature, and releases the adsorbed specific component when its temperature is equal to or higher than the release temperature; When its own temperature is higher than the activation temperature higher than the release temperature, a catalyst that oxidizes or reduces the specific component released from the adsorbent and an upstream side of the adsorbent are arranged to exchange heat with the exhaust gas. A heat recovery unit that recovers heat from exhaust gas, and a determination for determining whether the temperature of the adsorbent is equal to or higher than the discharge temperature and whether the catalyst is in a warm-up request state where the temperature of the catalyst is lower than the activation temperature. And heat recovery for performing heat recovery reduction control for reducing the amount of heat recovered by the heat recovery device when it is determined that the warm-up request state is determined, and when it is determined that the warm-up request state is not determined Reduction control means Output increase control means for performing output increase control for increasing the output of the internal combustion engine when it is determined that the warm-up request state is determined, compared with when it is determined that the warm-up request state is not determined; A drive load that performs drive load increase control that increases the drive load of the device driven by the output of the internal combustion engine when it is determined that the engine is in a required state and when it is determined that it is not in the warm-up required state And an increase control means.

  According to this, since the heat recovery device for recovering heat from the exhaust gas is arranged upstream of the adsorbent and the amount of heat recovery is reduced when the engine is in the warm-up request state (heat recovery reduction control), immediately after starting the internal combustion engine Increase in exhaust gas temperature can be promoted. Furthermore, since the output of the internal combustion engine is increased (output increase control) when it is in the warm-up request state, the exhaust gas temperature rise immediately after the start of the internal combustion engine can be further promoted. Therefore, the exhaust gas temperature rise can be promoted without retarding the ignition timing (or suppressing the ignition retard amount), so that the catalyst warm-up can be completed early while suppressing the deterioration of fuel consumption due to the retarded ignition timing. it can.

  Here, when the output increase control is performed, there is a concern that the output of the internal combustion engine increases against the driver's output request, and the driving output of the vehicle, for example, increases to give the driver a sense of incongruity. In response to this concern, according to the above-described invention, when the output increase control is performed, the drive load of the device driven by the output of the internal combustion engine is increased (drive load increase control). It is possible to eliminate the increase in travel output due to the output increase control. Therefore, it is possible to eliminate the above-mentioned concern that the driver feels uncomfortable.

  According to a second aspect of the present invention, the thermal energy supplied to the catalyst is predetermined by performing the heat recovery decrease control without performing the output increase control when it is determined that the warm-up request state is established. Output increase necessity determination means for determining whether or not a value can be secured, and the output increase control is performed on condition that the thermal energy cannot be secured above a predetermined value by the output increase necessity determination means. It is characterized by carrying out.

  According to this, when the heat energy required for catalyst warm-up can be supplied from the exhaust gas only by performing the heat recovery decrease control without performing the output increase control, the heat recovery increase without performing the output increase control. Since the control is to be performed, the chances that the fuel consumption deteriorates due to the output increase control can be reduced.

  According to a third aspect of the present invention, the device is a generator that generates power by being driven by the output of the internal combustion engine, and the state of charge of the battery is generated by the generator due to the increase in output by the output increase control. A power generation increase / decrease determination unit that determines whether or not the power can be charged is provided, and the output is determined on the condition that the power generated by the output increase is determined to be in a chargeable state. Increasing control is performed.

  For example, when the state of charge (SOC) of the battery is fully charged (SOC = 100%) or close to 100%, even if the output increase of the internal combustion engine is generated by the generator, the generated power is Cannot be charged (even if it can be charged, it will be overcharged and battery life will be shortened). On the other hand, according to the above-mentioned invention, when the SOC of the battery is high and the electric power generated by the output increase cannot be charged, the execution of the output increase control is not permitted. This will surely eliminate the concern that the driver will feel uncomfortable.

1 is a diagram showing a schematic configuration of an entire engine control system in a first embodiment of the present invention. The figure which shows the purification apparatus single-piece | unit of FIG. The flowchart which shows the process sequence of heat recovery reduction | decrease control, engine output increase control, and electric power generation amount increase control in 1st Embodiment. The time chart which shows the one aspect | mode by having implemented the process of FIG. The time chart which shows the one aspect | mode by having implemented heat recovery reduction | decrease control, engine output increase control, and electric power generation amount increase control in 2nd Embodiment of this invention. The figure which shows schematic structure of the whole engine control system in 3rd Embodiment of this invention.

  Hereinafter, embodiments embodying the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other are denoted by the same reference numerals in the drawings, and the description of the same reference numerals is used.

(First embodiment)
The exhaust gas purifying apparatus according to this embodiment is applied to an ignition type gasoline engine (internal combustion engine). First, a schematic configuration of the entire engine control system will be described with reference to FIG.

  An intake pipe 12 of an engine 11 that is an internal combustion engine is provided with a throttle valve 13 that adjusts the throttle opening, and fuel is injected into each branch pipe portion of each cylinder of the intake manifold 14 that introduces air into each cylinder. A fuel injection valve 15 is attached.

  On the other hand, in the exhaust pipe 16 of the engine 11, a purification device 30 that reduces harmful components in the exhaust gas is installed in a downstream portion of the exhaust manifold 17. FIG. 2A is a view of the purification device 30 as viewed from the exhaust gas flow direction, and FIG. 2B is an enlarged view of FIG. As shown in FIG. 2, the purification device 30 includes a three-way catalyst that purifies HC, CO, and NOx or an oxidation catalyst that purifies HC and CO (hereinafter simply referred to as “catalyst 33”), and an adsorption that adsorbs HC. And a material 32.

  More specifically, the purifying device 30 coats an adsorbent 32 such as zeolite on the inner wall surface of a carrier 31 formed in a honeycomb shape with a ceramic such as cordierite, and the surface of the adsorbent 32 is a three-way catalyst. Alternatively, a catalyst 33 such as an oxidation catalyst is supported by a coating or the like. The catalyst 33 is formed in a porous shape having innumerable fine holes, and HC in the exhaust gas passes through the fine holes of the catalyst 33 and is adsorbed by the adsorbent 32.

  The carrying amount of the catalyst 33 of the purification device 30 is formed so that the downstream portion is larger than the upstream portion of the purification device 30, and the HC purification reaction amount in the downstream portion of the purification device 30 is increased. . Further, the zeolite forming the adsorbent 32 has a characteristic that the heat resistance improves as the ratio of silica / alumina as the raw material increases, but the HC adsorption rate decreases. The adsorbent 32 (zeolite) increases the ratio of silica / alumina in the upstream part exposed to high heat to ensure heat resistance, and decreases the ratio of silica / alumina in the downstream part where the temperature is lower than the upstream part. The HC adsorption rate is increased.

  The adsorbent 32 adsorbs HC in the exhaust gas at a low temperature when the temperature of the adsorbent 32 is lower than the discharge temperature T1. On the other hand, when its own temperature becomes equal to or higher than the release temperature T1, the adsorbed HC is released and released. Further, the catalyst 33 is activated when its own temperature becomes equal to or higher than the activation temperature T2 (for example, about 250 ° C.), and functions to oxidize and reduce HC, CO, and NOx are exhibited. The activation temperature T2 is higher than the discharge temperature T1.

  At the time of cold start of the engine 11 whose exhaust gas temperature is low, the catalyst 33 is inactive because the catalyst temperature Tc is lower than the activation temperature T2, and the HC discharged from the engine 11 is purified. Can not do it. Therefore, during a period in which the catalyst 33 is inactive and HC cannot be purified, HC in the exhaust gas flowing into the purification device 30 passes through the fine holes of the catalyst 33 and is once adsorbed by the adsorbent 32. Thereafter, when the temperature of the purifier 30 rises, the adsorbent temperature Ta rises to the discharge temperature T1, and the catalyst temperature Tc rises to the activation temperature T2, HC released from the adsorbent 32 is oxidized by the catalyst 33. It will be purified.

  Since the catalyst 33 is carried on the upper layer side of the adsorbent 32, the catalyst 33 is directly exposed to the exhaust gas. Therefore, the catalyst temperature Tc is always higher than the adsorbent temperature Ta. Therefore, the time from the time when the adsorbent temperature Ta reaches the release temperature T1 and the release of HC to the time when the catalyst temperature Tc reaches the activation temperature T2 and can be purified can be shortened. Therefore, it is possible to prevent HC released from the adsorbent 32 from being discharged from the purification device 30 without being purified by the catalyst 33.

  An engine control circuit (hereinafter referred to as “ECU18”) is configured mainly by a microcomputer, and executes an engine operation by executing a fuel injection control program (not shown) stored in a built-in ROM (storage medium). The fuel injection amount of the fuel injection valve 15 is controlled according to the state (for example, engine speed and engine load). Specifically, the relationship between the engine speed and the engine load and the optimum injection amount is obtained by testing in advance, and the relationship between the engine speed and the engine load and the optimum injection amount created based on the test is shown. With reference to the injection amount map, the optimum injection amount (target injection amount) is calculated based on the engine rotation speed and the engine load.

  The ECU 18 controls the ignition timing of the spark plug 19 by executing an ignition control program (not shown) stored in the ROM. Specifically, the relationship between the engine speed and the engine load and the optimum injection amount is obtained by testing in advance, and the relationship between the engine speed and the engine load and the optimum ignition timing created based on the test is shown. Referring to the ignition timing map, the optimal ignition timing (target ignition timing) is calculated based on the engine speed and the engine load.

  When the engine 11 is cold started, the exhaust gas temperature is controlled by performing catalyst warm-up control (ignition delay control) such as an increase correction for increasing the fuel injection amount or a delay angle correction for retarding the ignition timing. The catalyst 33 can be activated early by promoting the increase.

  The engine 11 shown in FIG. 1 is a water-cooled type that is cooled by cooling water (heat medium), and the cooling water that exchanges heat with the engine 11 is cooled by heat exchange with the outside air by the radiator 20. A bypass pipe 22 that bypasses the radiator 20 and circulates the cooling water is connected to the circulation pipe 21 that circulates the cooling water between the engine 11 and the radiator 20. At the time of cold start when the cooling water temperature is equal to or lower than a predetermined temperature, the thermostat 23 (switching valve) is operated so that the cooling water is circulated through the bypass pipe 22 by bypassing the radiator 20. Thereby, warming-up promotion of the engine 11 is achieved. On the other hand, if the cooling water temperature is equal to or higher than the predetermined temperature, the thermostat 23 is operated so that the cooling water circulates through the radiator 20.

  The cooling water is circulated by a water pump 24 that operates using the engine output as a drive source. Therefore, the higher the engine rotation speed, the higher the rotation speed of the water pump 24, the circulation flow rate also increases, and the amount of cooling water heat exchanged with the outside air by the radiator 20 (the amount to be cooled) also increases. The cooling water is also used as a heat source for an air conditioner that air-conditions the interior of the vehicle. The air blown toward the interior of the vehicle is heated by heat exchange with the cooling water to become warm air. It is blown into the room.

  A heat recovery unit 40 that recovers heat from the exhaust gas by circulating a heat medium that exchanges heat with the exhaust gas is installed in the exhaust pipe 16 at a downstream portion of the exhaust manifold 17 and an upstream portion of the purification device 30. . In the present embodiment, cooling water circulated by the water pump 24 is used as a heat medium circulated in the heat recovery unit 40.

  The heat recovery pipe 25 that circulates the cooling water between the engine 11 and the heat recovery unit 40 is provided with a flow rate adjusting valve 41 (flow rate adjusting means) that adjusts the flow rate of the cooling water. The flow rate adjustment valve 41 is an electromagnetic valve, and the opening degree of the electromagnetic valve is controlled by the ECU 18. Then, by controlling the valve opening degree, the circulation flow rate through which the cooling water circulates through the heat recovery device 40 is adjusted (controlled).

  Therefore, if the valve opening degree of the flow rate adjustment valve 41 is fully closed and the circulation flow rate to the heat recovery device 40 is made zero, the entire amount of cooling water discharged from the water pump 24 circulates in the circulation pipe 21. On the other hand, if the flow rate adjustment valve 41 is opened, a part of the cooling water discharged from the water pump 24 circulates to the heat recovery unit 40, and the cooling water recovers heat by exchanging heat with the exhaust gas. By recovering heat from the exhaust gas in this manner, warm-up of the engine 11 can be promoted during cold start of the engine 11, and early heating of the conditioned air blown into the passenger compartment can be achieved.

  An exhaust gas temperature sensor 42 that detects the exhaust gas temperature is provided in an upstream portion of the heat recovery unit 40 in the exhaust pipe 16. The temperature detected by the exhaust gas temperature sensor 42 is the exhaust gas flowing into the heat recovery device 40 and is the temperature of the exhaust gas before heat exchange (hereinafter referred to as “exhaust gas inlet temperature Tex”). Based on the detected exhaust gas inlet temperature Tex, the ECU 18 controls the operation of the flow rate adjustment valve 41 to adjust the circulation flow rate to the heat recovery unit 40, thereby adjusting the exhaust heat recovery amount.

  The vehicle shown in FIG. 1 is a so-called hybrid vehicle, and in addition to the output of the engine 11, the output of a motor generator 27 (generator) that is driven by being supplied with power from the battery 26 is used as a travel drive source. It is also possible to charge the battery 26 with electric power generated by driving the motor generator 27 with engine output. In the example of FIG. 1, the crankshaft that is rotationally driven by the engine 11 is assisted and driven by the motor generator 27. Then, the outputs of the engine 11 and the motor generator 27 are transmitted to the transmission 28 to drive the drive wheels 29.

  The ECU 18 performs charge / discharge control so that the state of charge (SOC) of the battery 26 is within a predetermined range. In particular, when the SOC indicating the charging rate is lower than the lower limit value, the motor generator 27 generates electric power with the engine output to charge the battery 26. Therefore, in this case, the assist by the motor generator 27 is not possible. Further, when the SOC is 100% or higher than the upper limit value, charging the battery 26 causes the battery 26 to deteriorate. Therefore, in this case, control is performed such that charging of the battery 26 is prohibited or power generation by the motor generator 27 is prohibited.

  By the way, when the engine 11 is cold-started, if the catalyst warm-up control (ignition delay angle control) such as the ignition timing delay angle correction described above is performed, the fuel consumption deteriorates. Therefore, in the present embodiment, in order to suppress such fuel consumption deterioration, from the time when the adsorbent temperature Ta reaches the release temperature T1 to the time when the catalyst temperature Tc reaches the activation temperature T2, the “decrease in heat recovery” will be described below. Control, “engine output increase control” and “power generation increase control (drive load increase control)” are executed. The adsorbent temperature Ta and the catalyst temperature Tc are estimated based on the detected value of the exhaust gas temperature sensor 42 (exhaust gas inlet temperature Tex), the amount of heat recovery, and the like.

  In the “heat recovery reduction control”, the circulation of the cooling water to the heat recovery unit 40 is stopped (or circulated) so as to accelerate the temperature rise of the catalyst temperature Tc and accelerate the catalyst temperature Tc to reach the activation temperature T2. Reduce flow rate) to minimize heat recovery. Thereby, the exhaust gas inlet temperature Tex is increased. In the “engine output increase control”, the engine output is increased by performing correction so as to increase the target injection amount (normal target injection amount) calculated based on the above-described injection amount map. As a result, the rise of the exhaust gas inlet temperature Tex is promoted, and the catalyst warm-up is accelerated and the catalyst warm-up is completed early.

  When the catalyst temperature Tc reaches the activation temperature T2, the engine output increase control and the power generation amount increase control are terminated at that point, and thereafter, control is performed so that fuel is injected at the normal target injection amount.

  FIG. 3 is a flowchart showing a processing procedure of heat recovery reduction control, engine output increase control, and power generation increase control by the microcomputer of the ECU 18. The processing is repeatedly executed at a predetermined cycle (for example, every calculation cycle performed by the above-described CPU or every predetermined crank angle) after being activated with the ignition switch being turned on as a trigger.

  First, in step S10 shown in FIG. 3, the exhaust gas inlet temperature Tex detected by the exhaust gas temperature sensor 42 is acquired. Further, the catalyst temperature Tc is estimated based on the acquired exhaust gas inlet temperature Tex and the amount of heat recovered by the heat recovery unit 40. The heat recovery amount may be calculated based on the opening degree of the flow rate adjustment valve 41 and the engine coolant temperature. Then, a temperature decrease due to heat exchange in the heat recovery unit 40 is calculated based on the calculated heat recovery amount, and the catalyst temperature Tc is calculated by subtracting the temperature decrease from the exhaust gas inlet temperature Tex. In the process of FIG. 3, the adsorbent temperature Ta is considered to be the same as the catalyst temperature Tc.

  In subsequent step S11 (determination means), it is determined whether or not the catalyst temperature Tc calculated in step S10 is lower than the activation temperature T2. If it is determined that Tc <T2 (S11: YES), it is determined in subsequent step S12 (determination means) whether or not the adsorbent temperature Ta is higher than the discharge temperature T1. Here, the adsorbent temperature Ta is regarded as the same temperature as the catalyst temperature Tc. When it is determined that Tc> T1 is satisfied (S12: YES), it is regarded as a warm-up request state in which an increase in the catalyst temperature Tc is required, and the flow rate adjustment is performed in the subsequent step S13 (heat recovery reduction control means). The heat recovery reduction control is performed by controlling the valve 41 to be fully closed.

  In short, if catalyst temperature Tc <activation temperature T2 and adsorbent temperature Ta> release temperature T1, HC is released from adsorbent 32, but it is considered that the released HC cannot be purified by catalyst 33. In order to complete catalyst warm-up early, heat recovery reduction control is implemented. As a result, the rise of the exhaust gas inlet temperature Tex and thus the rise of the catalyst temperature Tc and the adsorbent temperature Ta can be promoted, so that the time until the catalyst temperature Tc reaches the activation temperature T2 can be shortened.

  On the other hand, when it is determined that the adsorbent temperature Ta ≦ the discharge temperature T1 (S12: NO), it is considered that the adsorbent 32 is adsorbing HC, and the process of FIG. However, even when the adsorbent temperature Ta ≦ the discharge temperature T1, if the HC adsorbed by the adsorbent 32 has reached the saturation amount, the process proceeds to step S13 and the heat recovery reduction control is performed. Also good.

  On the other hand, if it is determined that the catalyst temperature Tc ≧ the activation temperature T2 (S11: NO), the process proceeds to step S20, and the engine is set so that the target engine output during normal operation is achieved without performing engine output increase control. Control. For example, the fuel injection is controlled so as to be the normal target injection amount. Further, the catalyst is not warmed up by ignition retard control.

  In subsequent step S14 (output increase necessity determination means), it is determined whether or not the heat energy required for warming up the catalyst can be sufficiently supplied to the catalyst 33 only by the heat recovery decrease control. Specifically, the time required for the catalyst temperature Tc to reach the activation temperature T2 is determined based on the thermal energy supplied to the catalyst 33 by the exhaust gas whose temperature has increased by the heat recovery reduction control and the current catalyst temperature Tc. If the calculated time is within a preset target time, it is determined that heat energy required for catalyst warm-up can be supplied only by heat recovery reduction control.

  If an affirmative determination is made in step S14, the process of FIG. 3 is terminated without performing the output increase control and the catalyst warm-up by the ignition delay angle. On the other hand, if a negative determination is made in step S14, in the subsequent step S15, the output increase amount by which the engine output is increased by the output increase control is calculated. Then, in the next step S16, the amount of power generated by the motor generator 27 corresponding to the output increase calculated in step S15 is calculated.

  In the subsequent step S17 (power generation increase possibility determination means), whether or not the power generation amount calculated in step S16 is larger than the chargeable amount of the battery 26, that is, even if all the power generation amount is charged to the battery 26, the SOC It is determined whether or not the upper limit value is not exceeded. If it is determined that the power generation amount ≦ the chargeable amount (S17: NO), in the subsequent step S18 (output increase control means, drive load increase control means (power generation increase control means)), engine output increase control is performed and power generation is performed. Perform volume increase control. On the other hand, if it is determined that the power generation amount> the chargeable amount (S17: YES), the process proceeds to step S19, and the exhaust gas temperature is determined by performing the ignition retard control without performing the engine output increase control and the power generation increase control. To warm up the catalyst.

  When engine output increase control is not performed, injection control is performed so that the target injection amount (normal target injection amount) calculated based on the previously described injection amount map is obtained. The engine output increase control is a control for increasing the normal target injection amount by a predetermined amount set in advance. The control for increasing the amount of power generated by the motor generator 27 by an increase in output corresponding to the amount of increase and charging the battery 26 is the power generation amount increase control.

  FIG. 4 is a time chart showing an embodiment by performing the process of FIG. 4 (a) is the driving power of the vehicle, (b) is the engine output, (c) is the charge / discharge amount of the battery 26, (d) is the exhaust heat quantity directly under the engine, and (e) is the exhaust heat by the heat recovery device 40. The recovered amount, (f) indicates the catalyst temperature Tc, the solid line in (g) indicates the flow rate of HC flowing into the catalyst 33, and the alternate long and short dash line in (g) indicates the flow rate of HC flowing out from the catalyst 33.

  From the time t1 when the engine is started until the adsorbent temperature Ta reaches the discharge temperature T1, “heat recovery increase control” and “engine output decrease control” described below may be performed. In the “heat recovery increase control”, the flow rate (circulation flow rate) of the cooling water circulating through the heat recovery unit 40 is set so as to delay the temperature increase of the adsorbent temperature Ta and delay the adsorbent temperature Ta from reaching the discharge temperature T1. Maximize heat recovery at maximum capacity. As a result, the temperature of the exhaust gas flowing into the purification device 30 is reduced. In “engine output reduction control”, the engine output is decreased by correcting the target injection amount (normal target injection amount) calculated based on the above-described injection amount map. As a result, the temperature of the exhaust gas flowing into the purification device 30 is reduced.

  Thus, if heat recovery increase control is implemented in the period until time t2, the amount of exhaust heat recovery increases as shown in (e). Further, if the motor output increase control is performed during the period up to the time t2, even if the engine output decrease control is performed, a decrease in travel power can be avoided and the travel power can be maintained at the travel power requested by the driver. . These controls are performed at the time t2 when the exhaust temperature directly under the engine (exhaust gas inlet temperature Tex) reaches the discharge temperature T1, or when the estimated catalyst temperature Tc (that is, the adsorbent temperature Ta) reaches the discharge temperature T1. End.

  Thereafter, at time t2 when the catalyst temperature Tc (that is, the adsorbent temperature Ta) reaches the discharge temperature T1, the heat recovery increase control and the engine output decrease control are terminated, and the heat recovery decrease control, the engine output increase control, and the power generation increase control are terminated. To implement. When the catalyst temperature Tc reaches the activation temperature T2, the heat recovery decrease control, the engine output increase control, and the power generation increase control are terminated.

  By performing the heat recovery reduction control after time t2, the amount of exhaust heat recovery is reduced as shown in (e). Further, by performing the engine output increase control after the time point t2 (see (b)), the exhaust heat quantity directly under the engine increases (see (d)). By performing these controls, the catalyst temperature Tc rapidly increases from the time point t2 (see (f)). Therefore, the exhaust gas temperature rise can be promoted without retarding the ignition timing (or suppressing the ignition retard amount), so that the catalyst warm-up can be completed early while suppressing the deterioration of fuel consumption due to the retarded ignition timing. it can.

  Furthermore, by performing the power generation amount increase control after time t2, the battery charge amount increases as shown in (c). Therefore, it is possible to eliminate an increase in the actual travel output in response to the driver's travel output request due to the execution of the output increase control, and to prevent the driver from feeling uncomfortable.

  According to the embodiment described in detail above, the following effects are exhibited.

  (1) The temperature of the exhaust gas flowing into the purification device 30 (by adjusting the heat recovery amount by arranging the heat recovery device 40 upstream of the purification device 30 and adjusting the cooling water circulation flow rate to the heat recovery device 40 ( The exhaust gas outlet temperature Tout) can be adjusted.

  (2) Since the adsorbent temperature Ta reaches the discharge temperature T1, the circulation flow rate is reduced to zero (heat recovery decrease control) and the engine output is increased (output increase control). Can promote the rise. Therefore, the time until the catalyst temperature Tc reaches the activation temperature T2 can be shortened. Therefore, the exhaust gas temperature rise can be promoted without retarding the ignition timing (or by suppressing the ignition delay amount), so that the catalyst warm-up can be completed early while suppressing fuel consumption deterioration due to the ignition timing retardation. it can.

  (3) When the output increase control is performed, the output increase is generated and charged (power generation amount increase control), so that the actual travel output corresponding to the driver's travel output request performs the output increase control. Accordingly, it is possible to eliminate the increase and to prevent the driver from feeling uncomfortable.

  (4) It is determined whether or not the heat energy required for catalyst warm-up can be supplied from the exhaust gas only by performing the heat recovery decrease control without performing the output increase control (S14). (S14: YES), the heat recovery increase control is performed without performing the output increase control. Therefore, it is possible to reduce the opportunity for executing the output increase control and to improve the fuel consumption.

  (5) It is determined whether or not the power generation amount corresponding to the output increase amount by the output increase control is larger than the chargeable amount of the battery 26 (S17), and if power generation amount> chargeable amount (S17: YES), exhaust gas temperature is raised by performing ignition retard control without performing engine output increase control and power generation amount increase control, and catalyst warm-up is performed. Therefore, it is possible to reliably avoid such a problem that the output of the vehicle increases due to the output increase control and the driver feels uncomfortable.

(Second Embodiment)
In the first embodiment, when the adsorbent temperature Ta rises to the discharge temperature T1, the execution start timing of the heat recovery decrease control, the engine output increase control, and the power generation increase control is made the same. Then, the implementation of the heat recovery decrease control is started prior to the engine output increase control and the power generation increase control.

  Strictly speaking, the adsorbent 32 starts to be released at a temperature lower than the release temperature T1 (release start temperature). However, if it is lower than the release temperature T1, the adsorption function is also exhibited. That is, when the adsorbent temperature Ta is in a temperature range that is equal to or higher than the discharge start temperature (for example, 100 ° C.) and lower than the discharge temperature T1 (for example, 150 ° C.), the adsorption and the discharge are simultaneously performed and the temperature rises to the discharge temperature T1 At that time, the adsorption function is not exhibited.

  In the temperature range (100 ° C. ≦ Ta <150 ° C.), the adsorption rate gradually decreases as the adsorbent temperature Ta increases. In view of this point, in the example shown in FIG. 5 (h), the timing for starting the heat recovery decrease control is set to the time t2a when the adsorbent 32 reaches the discharge start temperature, and the engine output increase control and the power generation increase control are started. The timing is the time t2 when the adsorbent 32 reaches the discharge temperature T1. In this case, the release temperature described in the claims corresponds to the release start temperature.

  According to this, since the heat recovery reduction control is started earlier than the time point t2, early completion of catalyst warm-up can be promoted. If the heat recovery reduction control is started earlier than the time point t2a contrary to the present embodiment, the time to reach the discharge start temperature is advanced, and a sufficient amount of HC adsorbed by the adsorbent 32 cannot be secured. On the other hand, if the heat recovery reduction control is started later than the time point t2a, the completion of catalyst warm-up is delayed. In short, in this embodiment, the balance between the increase in the HC adsorption amount and the early completion of the catalyst warm-up can be optimized by starting the heat recovery reduction control at the time t2a.

  Further, according to the present embodiment, the engine output increase control is started later than the time point t2a, so that the deterioration of exhaust emission due to the engine output increase control can be reduced. If the engine output increase control is started earlier than the time point t2 contrary to the present embodiment, the time to reach the discharge start temperature is advanced, and a sufficient amount of HC adsorbed by the adsorbent 32 cannot be secured. On the other hand, if engine output increase control is started later than the time point t2, completion of catalyst warm-up will be delayed. In short, in the present embodiment, the engine output increase control is started at time t2, so that the balance between the reduction of exhaust emission and the early completion of catalyst warm-up can be optimized.

(Third embodiment)
In the first embodiment, the power generation amount increase control is performed as the drive load increase control. That is, the output increase due to the engine output increase control is generated by the motor generator 27 (device driven by the output of the internal combustion engine) and converted into electric power, and the generated electric power is charged in the battery 26. On the other hand, in this embodiment, the cold storage amount increase control described below is performed as the drive load increase control.

  FIG. 6 is a diagram illustrating a schematic configuration of the entire engine control system according to the present embodiment. The vehicle shown in FIG. 6 includes a compressor 50 (device driven by the output of the internal combustion engine) that uses the engine output as a drive source. An air conditioner equipped with is installed. The compressor 50 sucks and discharges the refrigerant in order to circulate the refrigerant in the refrigeration cycle.

  The compressor 50 is a variable capacity compressor capable of continuously setting the refrigerant discharge capacity by energization operation of an electromagnetically driven control valve (CV50a) included in the compressor 50, and the rotational power of the crankshaft of the engine 11 is controlled by the compressor. 50, the discharge capacity is adjusted by energizing the CV 50a. In the following description, it is assumed that the compressor 50 is driven when the discharge capacity is greater than 0, and the compressor 50 is stopped when the discharge capacity is 0.

  The refrigerant compressed by the compressor 50 is cooled by exchanging heat with the outside air in the condenser 51 and then separated into gas and liquid by the receiver 52. The liquid refrigerant in the receiver 52 is rapidly expanded by the expansion valve 53 and then evaporated by the evaporator 54 (evaporator). The air blown from the blower fan 55 that is rotationally driven by a DC motor or the like is cooled by exchanging heat with the refrigerant in the evaporator 54 and then blown into the vehicle compartment as cold air.

  Further, the evaporator 54 has a cool storage agent 54a (for example, paraffin) enclosed therein, and is configured to be capable of storing cold (accumulating heat) by cooling the cool storage agent 54a with the refrigerant evaporated in the evaporator 54. ing. Specifically, when the compressor 50 is driven, heat of the refrigerant is stored in the evaporator 54 by heat exchange between the refrigerant supplied to the evaporator 54 and the cold storage agent 54a. After that, the air blown from the blower fan 55 and the cool storage agent 54a exchange heat with the compressor 50 being stopped, whereby the blown air is cooled and the cooled air is sent into the vehicle interior. This makes it possible to cool the passenger compartment.

  In the present embodiment, the air conditioner capable of accumulating in this way is adopted, and when the engine output increase control is performed, the discharge capacity is increased by the CV 50a (for example, the discharge capacity is maximized) and the operation of the blower fan 55 is stopped. (Cool storage amount increase control) As a result, the compressor 50 can be driven by the output increase by the engine output increase control to store the cold in the cool storage agent 54a, and when the cool air is required to be blown into the vehicle interior, the blower fan 55 is operated. The blown air is cooled by the cold storage agent 54a.

  Note that when the temperature of the evaporator 54 becomes equal to or lower than the set temperature, moisture adhering to the outer surface of the evaporator 54 is frozen (frosted), and the heat exchange efficiency is significantly reduced. Therefore, in order to prevent such frost, when the temperature of the evaporator 54 (or the air temperature on the downstream side of the evaporator 54) is equal to or lower than a predetermined temperature, the discharge capacity is reduced by the CV 50a. By performing such frost prevention control, the compressor 50 may not be driven even during the engine output increase control. If the cold storage cannot be performed as described above, the engine output increase control is prohibited in the same manner as in the affirmative determination in step S17 of FIG. 3, and the catalyst is warmed up by the ignition delay as in step S19 of FIG. It is desirable.

  As described above, the same effects as those of the first embodiment are also exhibited by the present embodiment in which the cold storage amount increase control is performed instead of the power generation amount increase control.

(Other embodiments)
The present invention is not limited to the description of the above embodiment, and may be modified as follows. Moreover, you may make it combine the characteristic structure of each embodiment arbitrarily, respectively.

  In performing step S19 in FIG. 3, the ignition retard control may be performed while the output increase control and the power generation increase control are performed by the chargeable amount. According to this, compared with the case of FIG. 3 in which the output increase control and the power generation amount increase control are not performed at all, it is possible to suppress the ignition retard amount and suppress the deterioration of fuel consumption.

  In each of the above embodiments, in the heat recovery unit 40, the engine cooling water flowing through the radiator 20 and the exhaust gas are heat exchanged. However, the engine cooling water is heat exchanged with another heat medium, and the other heat You may make it heat-exchange a medium and waste gas. In the heat recovery increase control in this case, the circulating flow rate of the engine cooling water may be increased, the circulating flow rate by the electric pump for circulating the other heat medium may be increased, or both the circulating flow rates may be increased. You may let them.

  In the embodiment shown in FIG. 1, the heat recovery increase control is performed by controlling the opening degree of the flow rate adjustment valve 41. For example, the exhaust gas bypasses the heat recovery device 40 and exhausts the bypass passage. You may make it provide the switching valve which forms in the pipe | tube 16 and switches the distribution route of waste gas to either a bypass passage or the heat recovery device 40. In this case, the heat recovery increase control may be performed by controlling the operation of the switching valve to switch from the state in which the exhaust gas is circulated to the bypass passage to the state in which the exhaust gas is circulated to the heat recovery unit 40.

  In each of the above embodiments, the flow rate adjusting valve 41 is provided as the heat recovery amount adjusting means. However, in an engine in which the water pump 24 is driven by an electric motor, it is circulated by variably controlling the rotational speed of the water pump 24. Since the flow rate can be adjusted, the flow rate adjustment valve 41 may be eliminated in this case, and the circulation flow rate to the heat recovery unit 40 may be adjusted by controlling the operation of the water pump 24.

  In the embodiment shown in FIG. 1, an exhaust gas temperature sensor 42 is provided in the exhaust pipe 16 upstream of the heat recovery device 40, and the catalyst temperature Tc and the adsorbent temperature Ta are estimated and controlled from the exhaust gas inlet temperature Tex. However, such a temperature sensor may be provided in the purification device 30 to directly detect the temperature of the catalyst 33. Alternatively, the exhaust gas temperature sensor 42 is arranged on the downstream side of the heat recovery unit 40, and the catalyst temperature Tc and the adsorbent temperature Ta are set based on the detection value by the exhaust gas temperature sensor 42, the circulating flow rate of the cooling water, and the operating state of the engine 11. You may make it estimate.

  In each of the above embodiments, the purification device 30 in which the adsorbent 32 and the catalyst 33 are integrally formed is employed. However, in the implementation of the present invention, the adsorbent 32 and the catalyst 33 may be configured separately. Good. In this case, it is desirable to arrange the adsorbent upstream of the catalyst so that the ambient temperature of the adsorbent is higher than the ambient temperature of the catalyst. According to this, the time from when the adsorbent temperature reaches the discharge temperature T1 to the time when the catalyst reaches the activation temperature T2 (the time during which neither adsorption nor oxidation is performed) can be shortened.

  In the second embodiment, the motor generator 27 having a motor function and a power generation function is adopted as an electric motor. However, an electric motor not having a power generation function may be adopted.

  In each of the above embodiments, the specific component in the exhaust gas to be purified is HC, and the present invention is applied to the adsorbent / catalyst that adsorbs / oxidizes this HC, but the present invention is limited to this. It is not a thing. For example, in the case of a lean burn gasoline engine or diesel engine, the present invention may be applied to an adsorbent that adsorbs NOx in exhaust gas as a specific component and a catalyst that reduces the NOx.

  27: motor generator (device driven by the output of the internal combustion engine), 32 ... adsorbent, 33 ... catalyst, 40 ... heat recovery device, 50 ... compressor (device driven by the output of the internal combustion engine), S11, S12 ... determination means , S13 ... heat recovery decrease control means, S14 ... output increase necessity determination means, S17 ... generated power increase enable / disable determination means, S18 ... output increase control means, drive load increase control means (power generation increase control means), T1 ... release Temperature, T2 ... Activation temperature.

Claims (3)

An adsorbent that adsorbs a specific component in the exhaust gas of an internal combustion engine when its temperature is lower than the release temperature, and releases the adsorbed specific component when its temperature is equal to or higher than the release temperature;
A catalyst that oxidizes or reduces the specific component released from the adsorbent when its temperature is higher than an activation temperature higher than the release temperature;
A heat recovery device that is disposed upstream of the adsorbent and heat-exchanges with the exhaust gas to recover heat from the exhaust gas;
Determining means for determining whether or not the adsorbent is in a warm-up request state in which the temperature of the adsorbent is equal to or higher than the release temperature and the temperature of the catalyst is lower than the activation temperature;
Heat recovery reduction control means for performing heat recovery reduction control for reducing the amount of heat recovery by the heat recovery device when it is determined that the warm-up request state is determined, compared to when it is determined that the warm-up request state is not required When,
Output increase control means for performing output increase control for increasing the output of the internal combustion engine when it is determined that the warm-up request state is determined, compared to when it is determined that the warm-up request state is not determined;
When it is determined that the warm-up request state is determined, drive load increase control is performed to increase the drive load of the device driven by the output of the internal combustion engine, compared to when it is determined that the warm-up request state is not determined. Drive load increase control means;
An exhaust gas purification apparatus comprising: Whether or not the heat energy supplied to the catalyst can be secured to a predetermined value or more by performing the heat recovery decrease control without performing the output increase control when it is determined that the warm-up request state is established. An output increase necessity judging means for judging,
2. The exhaust gas purification apparatus according to claim 1, wherein the output increase control is performed on condition that the output energy necessity determination unit determines that the thermal energy cannot be secured above a predetermined value. The device is a generator that generates power by being driven by the output of the internal combustion engine,
A power generation increase / decrease determination unit that determines whether or not the state of charge of the battery is a state in which the power generated by the generator can be charged by the output increase by the output increase control;
3. The exhaust gas purification apparatus according to claim 1, wherein the output increase control is performed on the condition that it is determined that the power generated by the output increase can be charged. 4.

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