JP2010064599A - Control device and control method of vehicle - Google Patents

Abstract

An object of the present invention is to highly accurately limit the opening of a throttle valve in accordance with engine torque.
An engine ECU estimates an engine torque from an MG (1) torque (S100), and when a running condition is satisfied (YES in S102), and the engine torque is a threshold value Th. If larger than (0) (S104), a program including a step (S106) of executing throttle upper limit guard is executed.
[Selection] Figure 5

Description

  The present invention relates to vehicle control, and more particularly, to a technique for estimating an engine torque with high accuracy and limiting the opening of a throttle valve based on the estimated engine torque and engine torque constraint conditions.

  In recent years, as one of countermeasures for environmental problems, a hybrid vehicle that travels by driving force from an engine and a motor has attracted attention. The engine of such a hybrid vehicle is controlled along an operation line set based on the torque and the rotational speed in order to operate efficiently.

  As such a hybrid vehicle, for example, Japanese Patent Laid-Open No. 10-325344 (Patent Document 1) discloses a case where an operation mode in which the engine and the motor generator are cooperatively controlled is selected without increasing the size of the motor generator. A hybrid drive control device that prevents engine blow-up is disclosed. This hybrid drive control device includes an engine that operates by combustion of fuel, a motor generator that is used as at least one of an electric motor and a generator, a first rotating element that is connected to the engine, and a second rotation that is connected to the motor generator. A third rotating element coupled to the element and the output member, and a three-shaft power input / output means for mechanically synthesizing and distributing the force between them and the engine and the motor generator for coordinated output When the engine and the motor generator are cooperatively controlled by the cooperative drive means in the hybrid drive control device having the cooperative drive means for rotationally driving the member, the engine output torque is limited based on the maximum output torque of the motor generator. And engine output torque limiting means.

According to the hybrid drive control device disclosed in the above-mentioned publication, the reaction force torque required for the engine output torque can be increased to the maximum output of the motor generator without increasing the size of the motor generator or controlling the brake slip. It is possible to prevent the torque from being exceeded, and it is possible to prevent a decrease in durability of the motor generator due to engine blow-up or excessive load.
Japanese Patent Laid-Open No. 10-325344

  However, the hybrid drive control device disclosed in the above-mentioned publication has a problem that the estimation accuracy is low because the engine torque is estimated based on the throttle opening and the fuel injection amount. This is because there is variation in the engine torque that is expressed based on the throttle opening and the fuel injection amount for each engine. When the estimation accuracy of the engine torque is low, the throttle may be restricted more than necessary in order to reliably suppress the engine blow-up. Therefore, there is a possibility that the engine power cannot be fully exhibited.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a vehicle control device and a control method for accurately limiting the opening degree of a throttle valve in accordance with engine torque. is there.

  In the vehicle control apparatus according to the first invention, the vehicle includes an engine and a motor generator coupled to the output shaft of the engine. The engine includes a cylinder, an exhaust passage for exhausting gas in the cylinder, an exhaust valve provided between the exhaust passage and the cylinder, and a throttle valve for adjusting the flow rate of the gas introduced into the cylinder. This control device estimates the engine torque based on the engine torque reaction force in the motor generator, and reduces the upper limit value of the throttle valve opening when the engine torque is greater than a threshold value. Reduction means. The threshold is set based on at least one of the allowable torque of the motor generator, the maximum value of the pressure in the cylinder, and the exhaust pressure at which exhaust leakage to the exhaust passage occurs when the exhaust valve is closed. The The vehicle control method according to the eighth invention has the same configuration as the vehicle control device according to the first invention.

  According to the first invention, by estimating the engine torque based on the torque reaction force of the engine in the motor generator, there is no need to consider variation among individuals. Therefore, it is possible to estimate the engine torque with higher accuracy than when estimating based on the opening degree of the throttle valve and the fuel injection amount. Therefore, the estimated engine torque is a threshold value set based on the allowable torque of the motor generator, the maximum value of the pressure in the cylinder, and the exhaust pressure at which exhaust leakage to the exhaust passage occurs when the exhaust valve is closed By restricting the opening of the throttle valve when it is larger than this, it is possible to avoid the restriction of the opening of the throttle valve unnecessarily. Therefore, the engine torque power can be sufficiently exhibited as compared with the case where the engine torque is estimated based on the opening degree of the throttle valve and the fuel injection amount. Therefore, it is possible to provide a vehicle control device and a control method for accurately limiting the opening degree of the throttle valve according to the engine torque.

  In the vehicle control apparatus according to the second invention, in addition to the configuration of the first invention, the reducing means uses the upper limit value of the opening of the throttle valve as the engine torque so that the engine torque becomes equal to or less than the threshold value. Decrease by a value corresponding to the difference from the threshold. A vehicle control method according to a ninth aspect has the same configuration as the vehicle control apparatus according to the second aspect.

  According to the second invention, by restricting the opening of the throttle valve so that the engine torque becomes equal to or less than the threshold value, the engine speed increases due to the engine torque exceeding the allowable torque of the motor generator. It is possible to suppress the occurrence of a local high-temperature portion due to the maximum value of the pressure exceeding the value allowed in the engine and the occurrence of exhaust leakage into the exhaust passage when the exhaust valve is closed.

  In the vehicle control apparatus according to the third aspect of the invention, in addition to the configuration of the first or second aspect of the invention, the reducing means gradually increases the upper limit value of the throttle valve opening until the engine torque becomes equal to or lower than the threshold value. Reduce to. A vehicle control method according to a tenth invention has the same configuration as the vehicle control device according to the third invention.

  According to the third aspect of the invention, the upper limit value of the throttle opening is gradually reduced until the engine engine torque becomes equal to or lower than the threshold value, so that the engine speed blows when the engine torque exceeds the allowable torque of the motor generator. It is possible to suppress the occurrence of a local high temperature part due to the increase in the maximum value of the pressure in the cylinder exceeding the allowable value in the engine and the occurrence of exhaust leakage into the exhaust passage when the exhaust valve is closed. .

  In the vehicle control apparatus according to the fourth aspect of the invention, in addition to the configuration of any one of the first to third aspects, the estimating means includes the engine when the running state of the vehicle satisfies a predetermined running condition. Estimate torque. A vehicle control method according to an eleventh invention has the same configuration as the vehicle control device according to the fourth invention.

  According to the fourth invention, the engine torque is estimated when the traveling state of the vehicle satisfies a predetermined traveling condition (for example, a condition that the traveling state of the vehicle is a steady traveling state or a fully open traveling state). Thus, it is possible to estimate the engine torque when the driving state is high in estimation accuracy or the driving state in which the estimation error is easily identified. Therefore, the engine torque can be estimated with high accuracy.

  In the vehicle control apparatus according to the fifth aspect of the invention, in addition to the configuration of any one of the first to fourth aspects, the threshold value is set so that the engine torque does not exceed the allowable torque of the motor generator. A vehicle control method according to a twelfth aspect of the invention has the same configuration as the vehicle control apparatus according to the fifth aspect of the invention.

  According to the fifth aspect, by setting the threshold value so that the engine torque does not exceed the allowable torque of the motor generator, it is possible to prevent the engine speed from being increased.

  In the vehicle control apparatus according to the sixth aspect of the invention, in addition to the configuration of any one of the first to fifth aspects, the threshold value does not exceed a value that allows the maximum value of the pressure in the cylinder to be allowed in the engine. Is set as follows. A vehicle control method according to a thirteenth aspect has the same configuration as the vehicle control apparatus according to the sixth aspect.

  According to the sixth aspect of the invention, by setting the engine torque threshold value so that the maximum value of the pressure in the cylinder does not exceed the allowable value in the engine, various variations such as manufacturing variations of components and usage conditions Even if there is such a variation, it is possible to avoid the maximum value of the pressure in the cylinder from exceeding the value allowed in the engine, and therefore it is possible to suppress deterioration in the durability of the engine.

  In the vehicle control apparatus according to the seventh aspect of the invention, in addition to the configuration of any one of the first to sixth aspects, the threshold value is an exhaust gas that causes an exhaust leak into the exhaust passage when the exhaust valve is closed. It is set so as not to generate pressure. A vehicle control method according to a fourteenth aspect of the invention has the same configuration as the vehicle control device according to the seventh aspect of the invention.

  According to the seventh invention, by setting the engine torque threshold value so as not to generate an exhaust pressure that causes exhaust leakage into the exhaust passage when the exhaust valve is closed, the exhaust leakage is suppressed, Generation of a typical high temperature portion can be suppressed. Therefore, deterioration of engine durability can be suppressed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  With reference to FIG. 1, a control block diagram of a hybrid vehicle equipped with a vehicle control apparatus according to an embodiment of the present invention will be described.

  The hybrid vehicle includes an internal combustion engine (hereinafter referred to as an engine) 120 as a drive source and a motor generator (MG) 140 that is a rotating electrical machine. In FIG. 1, for convenience of explanation, the motor generator 140 is expressed as a generator 140A and a motor 140B, but the generator 140A functions as a motor or the motor 140B functions as a generator depending on the traveling state of the hybrid vehicle. To do.

  In the intake passage 122 of the engine 120, an air cleaner 122A that captures dust of intake air, an air flow meter 122B that detects the amount of air drawn into the engine 120 through the air cleaner 122A, and an amount of air drawn into the engine 120 are adjusted. An electronic throttle 122C having a throttle valve 122E is provided. The electronic throttle 122C is provided with a throttle position sensor 122D. An engine ECU (Electronic Control Unit) 280 receives an intake air amount detected by an air flow meter 122B, an opening of a throttle valve 122E (hereinafter also referred to as a throttle opening) detected by a throttle position sensor 122D, and the like. The

  Further, in the exhaust passage 124 of the engine 120, a three-way catalytic converter 124B, an air-fuel ratio sensor 124A for detecting an air-fuel ratio (A / F) in the exhaust gas introduced into the three-way catalytic converter 124B, a silencer 124C, Is provided.

  Engine 120 is provided with a plurality of cylinders 126 connected to intake passage 122 and exhaust passage 124. An intake valve 128 is provided between the intake passage 122 and the cylinder 126. Intake valve 128 operates in conjunction with the rotation of the output shaft of engine 120. Specifically, the intake valve 128 operates to open during the intake stroke of the engine 120 and close during the other strokes (compression stroke, expansion stroke, and exhaust stroke).

  An exhaust valve 130 is provided between the exhaust passage 124 and the cylinder 126. Exhaust valve 130 operates in conjunction with rotation of the output shaft of engine 120. Specifically, the exhaust valve 130 operates to open in the exhaust stroke of the engine 120 and close in other strokes (intake stroke, compression stroke, and expansion stroke).

  A crank position sensor 380 is provided on the output shaft of the engine 120, and a signal indicating the rotation speed of the output shaft is input from the crank position sensor 380 to the engine ECU 280.

  A rotation speed sensor 382 is provided on the output shaft of the motor 140B, and a signal indicating the rotation speed (MG (2) rotation speed) of the motor 140B is input to the MG_ECU 300. The signal indicating the MG (2) rotation speed transmitted to MG_ECU 300 is transmitted to engine ECU 280 via HV_ECU 320.

  The hybrid vehicle further includes a reduction gear 180 and a power split mechanism 200. Reducer 180 transmits power generated by engine 120 and motor generator 140 to drive wheel 160, and transmits drive of drive wheel 160 to engine 120 and motor generator 140. Power split device 200 is, for example, a planetary gear mechanism, and distributes the power generated by engine 120 to two paths of drive wheel 160 (that is, motor 140B) and generator 140A. The planetary gear mechanism includes a sun gear, a ring gear, a carrier, and a pinion gear. For example, the sun gear of the planetary gear mechanism is connected to the generator 140A, the carrier is connected to the engine, and the ring gear is connected to the motor 140B. A transmission mechanism may be provided between the ring gear and the motor 140B.

  Hybrid vehicle further includes a traveling battery 220 and an inverter 240. Traveling battery 220 is charged with electric power for driving motor generator 140. Note that a capacitor or the like may be used as the power storage device instead of the traveling battery. Inverter 240 performs current control while converting direct current of traveling battery 220 and alternating current of generator 140A and motor 140B.

  Further, the hybrid vehicle further includes a battery control unit (hereinafter referred to as a battery ECU) 260, an engine ECU 280, an MG_ECU 300, and an HV_ECU 320.

  Battery ECU 260 manages and controls the charge / discharge state of battery for traveling 220. Engine ECU 280 controls the operating state of engine 120. MG_ECU 300 controls motor generator 140, battery ECU 260, inverter 240, and the like according to the state of the hybrid vehicle. The HV_ECU 320 controls and controls the battery ECU 260, the engine ECU 280, the MG_ECU 300, and the like so that the hybrid vehicle can operate most efficiently.

  In the present embodiment, converter 242 is provided between battery for traveling 220 and inverter 240. This is because the rated voltage of the traveling battery 220 is lower than the rated voltage of the generator 140A and the motor 140B, and therefore when the power is supplied from the traveling battery 220 to the motor generator 140A and the motor 140B, the power is boosted by the converter 242. . This converter 242 has a built-in smoothing capacitor, and when the converter 242 performs a boosting operation, electric charge is stored in this smoothing capacitor.

  In FIG. 1, each ECU is configured separately, but may be configured as an ECU in which two or more ECUs are integrated (for example, as shown by a dotted line in FIG. 1, engine ECU 280 and MG_ECU 300 An example is an ECU integrated with the HV_ECU 320).

  The driver's seat is provided with an accelerator pedal (not shown), and an accelerator position sensor (not shown) detects the amount of depression of the accelerator pedal. The accelerator position sensor outputs a signal indicating the amount of depression of the accelerator pedal to the HV_ECU 320. The HV_ECU 320 controls the output of the engine 120 or the power generation amount of the generator 140A and / or the motor 140B via the generator 140A, the motor 140B, and the engine ECU 280 according to the required driving force corresponding to the depression amount.

  In power split mechanism 200, a planetary gear mechanism (planetary gear) is used to distribute the power of engine 120 to both drive wheel 160 and motor generator 140A. By controlling the rotation speed of motor generator 140A, power split device 200 also functions as a continuously variable transmission.

  In a hybrid vehicle equipped with a hybrid system as shown in FIG. 1, the hybrid vehicle travels only by the motor 140 </ b> B of the motor generator 140 when the engine 120 is inefficient, such as when starting or running at a low speed. During normal travel, for example, the power split mechanism 200 divides the power of the engine 120 into two paths, and on the other hand, the drive wheels 160 are directly driven, and on the other hand, the generator 140A is driven to generate power. At this time, the motor 140B is driven by the generated electric power to assist driving of the driving wheels 160. Further, at the time of high speed traveling, electric power from the traveling battery 220 is further supplied to the motor 140B to increase the output of the motor 140B to add driving force to the driving wheels 160.

  On the other hand, at the time of deceleration, the motor 140B driven by the drive wheel 160 functions as a generator to perform regenerative power generation, and the recovered power is stored in the traveling battery 220. When the amount of charge of traveling battery 220 decreases and charging is particularly necessary, the output of engine 120 is increased to increase the amount of power generated by generator 140A to increase the amount of charge for traveling battery 220. Of course, there is a case where control is performed to increase the driving force of the engine 120 as necessary even during low-speed traveling. For example, it is necessary to charge the traveling battery 220 as described above, to drive an auxiliary machine such as an air conditioner, or to raise the temperature of the cooling water of the engine 120 to a predetermined temperature.

  Furthermore, in a hybrid vehicle equipped with a hybrid system as shown in FIG. 1, engine 120 is stopped in order to improve fuel consumption depending on the driving state of the vehicle and the state of traveling battery 220. And after that, the driving | running state of the vehicle and the state of the battery 220 for driving | running | working are detected, and the engine 120 is restarted. In this way, the engine 120 is intermittently operated, and in a conventional vehicle (a vehicle equipped with only an engine), when the ignition switch is turned to the START position and the engine is started, the ignition switch is switched from the ON position to the ACC position. Or it is different in that the engine does not stop until it is in the OFF position.

  In the vehicle having the above configuration, for example, when the engine torque is estimated based on the throttle opening and the fuel injection amount, the estimation accuracy may be low. This is because there is variation in the engine torque that is expressed based on the throttle opening and the fuel injection amount for each engine.

  When the engine torque increases so as to exceed the allowable torque of generator 140A, the balance between the engine torque and the torque of generator 140A may be lost, and the engine speed may increase. As shown in the alignment chart of FIG. 2, the rotational speeds of the generator 140A, the motor 140B, and the engine 120 maintain the relationship of the solid line in FIG. 2 in a state where the torque is balanced. Here, if the engine torque increases above the allowable torque of the generator 140A, the increase in the engine speed cannot be suppressed by the generator 140A, so that the engine speed increases as shown by the broken line in FIG. .

  Further, when the engine torque increases so that the maximum value of pressure in the cylinder 126 (hereinafter referred to as Pmax) exceeds the allowable value (hereinafter referred to as allowable value) in the engine 120, the engine The durability of 120 may deteriorate.

  Further, when the engine torque increases so as to reach an exhaust pressure at which exhaust leakage into the exhaust passage 124 occurs when the exhaust valve 130 is closed, a local high temperature portion is generated. May get worse.

  Therefore, when the estimation accuracy of the engine torque is low, it is necessary to limit the throttle more than necessary in order to reliably suppress the engine speed increase or deterioration of durability, and the engine power can be fully utilized. It may not be possible.

  Therefore, according to the present invention, the engine ECU 280 estimates the engine torque based on the torque reaction force of the engine 120 in the generator 140A, and decreases the upper limit value of the throttle opening when the estimated engine torque is higher than the threshold value. It is characterized in that The threshold value is based on at least one of the allowable torque of the generator 140A, the maximum value of the pressure in the cylinder 126, and the exhaust pressure at which exhaust leakage to the exhaust passage 124 occurs when the exhaust valve 130 is closed. This is the value that is set. The estimation of the engine torque may be performed in the HV_ECU 320, or the upper limit value of the throttle opening is calculated based on the estimated engine torque by the HV_ECU 320, and the throttle opening is determined based on the calculated upper limit value. The electronic throttle 122C may be controlled to limit the degree.

  FIG. 3 shows a functional block diagram of engine ECU 280 which is a vehicle control apparatus according to the present embodiment. Engine ECU 280 includes an engine torque estimating unit 500, a traveling condition determining unit, a threshold determining unit 504, and an upper limit guard executing unit 506.

  Engine torque estimation unit 500 estimates engine torque based on the torque reaction force of engine 120 in generator 140A. Specifically, engine torque estimation unit 500 calculates torque generated in generator 140A (hereinafter referred to as MG (1) torque) based on the current value (MG (1) current value) of generator 140A received from HV_ECU 320. . Engine torque estimation unit 500 may calculate MG (1) torque based on the rotational speed of generator 140A and a map showing a change in torque with respect to a change in rotational speed obtained through experiments or the like.

  Engine torque estimating unit 500 calculates engine torque based on MG (1) torque. The rotational speeds of generator 140A, motor 140B, and engine 120 are maintained as shown by the solid lines in FIG. 4 when the torque is balanced. The torque generated by the generator 140A (MG (1) torque), the torque generated by the motor 140B (MG (2) torque), the engine torque, and the reaction force torque from the road surface are the cases where the vehicle is traveling normally. Etc. At this time, the engine torque and the MG (1) torque have a relationship of engine torque = (1 + ρ) / ρ × MG (1) torque, where the planetary gear ratio (number of sun gear teeth / number of ring gear teeth) is ρ. Therefore, by calculating the MG (1) torque that is the torque reaction force of the engine torque, the engine torque can be estimated with high accuracy using the above-described relationship.

  The traveling condition determination unit 502 determines whether or not the traveling state of the vehicle satisfies a predetermined traveling condition. The predetermined traveling condition is not particularly limited as long as it is a traveling condition that provides an estimation accuracy that is equal to or higher than a predetermined degree of engine torque. For example, the vehicle is in a steady traveling state (that is, the vehicle speed). Alternatively, the condition may be that the rotation speed of the motor 140B is substantially constant or the vehicle speed or the change amount of the rotation speed is equal to or less than a predetermined value), or the accelerator depression amount is maximized. For example, the condition may be a traveling state in which an estimation error can be specified. For example, the traveling condition determination unit 502 may turn on the traveling condition determination flag when the traveling state of the vehicle satisfies a predetermined traveling condition.

  The threshold determination unit 504 determines whether or not the estimated engine torque is greater than the threshold. Here, as described above, the threshold value is based on at least one of the allowable torque of generator 140A, Pmax, and exhaust pressure at which exhaust leakage to exhaust passage 124 occurs when exhaust valve 130 is closed. Is set.

  In the present embodiment, the threshold is set by adaptation of experiments or the like based on the allowable torque of generator 140A, Pmax, and the exhaust pressure at which exhaust leakage to exhaust passage 124 occurs when exhaust valve 130 is closed. However, according to the required performance or specifications of the engine, at least one of the allowable torque of the generator 140A, Pmax, and exhaust pressure at which exhaust leakage to the exhaust passage 124 occurs when the exhaust valve 130 is closed. The threshold value satisfying the selected condition may be adapted by experiment or the like.

  The allowable torque of generator 140A is designed and / or experimentally set according to the type, physique, use conditions, and various variations of the generator. The threshold value is set so that the engine torque does not exceed the allowable torque of generator 140A.

  The threshold value is set so that Pmax does not exceed the allowable value. Note that Pmax is set by design and / or experiment. For example, Pmax increases as the amount of intake air increases. Further, Pmax increases as the ignition timing advances until the ignition timing reaches MBT (Minimum Advance for Best Torque) or until knocking occurs. As the engine achieves higher output or lower fuel consumption, the difference between Pmax and the allowable value tends to be smaller.

  The threshold value is uniquely determined based on the set Pmax. However, since Pmax may fluctuate depending on the engine speed, preferably, a change in Pmax corresponding to a change in the engine torque and / or the engine speed is measured in advance through experiments or the like, and Pmax based on the measurement result is used. It is desirable to set a threshold value so that does not exceed the allowable value. Or you may make it change a threshold value using a map etc. by the change of an engine torque and / or an engine speed.

  Further, the threshold value is set so as not to generate an exhaust pressure that causes an exhaust leak to the exhaust passage 124 when the exhaust valve 130 is closed. Exhaust leakage to the exhaust passage 124 when the exhaust valve 130 is closed occurs when the amount of intake air is high and the exhaust pressure is high, and the combustion gas in the combustion chamber flows from a slight gap between the valve and the valve seat. When the exhaust gas leaks from the jet, a high temperature portion may be locally generated. Such a problem occurs when the tension of a spring that applies an urging force to the exhaust valve is closed in order to suppress friction loss in an engine that achieves high performance.

  Such exhaust leakage occurs when the intake air amount is high, that is, when the engine torque is high. Therefore, by limiting the upper limit value of the throttle opening, the intake air amount is reduced (that is, the engine torque is reduced). The exhaust pressure can be reduced.

  As the threshold setting method, in the present embodiment, any of the allowable torque of generator 140A, Pmax, and the exhaust pressure at which exhaust leakage to exhaust passage 124 occurs when exhaust valve 130 is closed is used. One threshold value satisfying such a condition may be set, or two or more threshold values may be set.

  For example, even when the engine torque exceeds the allowable torque of the generator 140A for a short time, the engine speed increases. Further, regarding the leakage of the exhaust gas to the exhaust passage 124 when the exhaust valve 130 is closed, the exhaust gas leaks even when the engine torque exceeds the engine torque causing the exhaust leakage for a short time. Therefore, one threshold value (1) is set so that at least the engine torque does not exceed the allowable torque of generator 140A and the exhaust pressure at which exhaust leakage occurs is not reached.

  In order to prevent Pmax from exceeding the allowable value, the allowable value considered from a short-time viewpoint is different from the allowable value considered from a long-time viewpoint. Set the threshold value (2).

  The threshold determination unit 504 determines whether or not the estimated engine torque is greater than at least one of the threshold (1) and the threshold (2). In this way, by setting a plurality of threshold values according to the constraint conditions, it is possible to appropriately limit the upper limit of the throttle valve opening.

  Note that the threshold determination unit 504 performs the above-described determination when the traveling condition determination flag is on, for example, and sets the threshold determination flag when the estimated engine torque is greater than the threshold. You may make it turn on.

  The upper limit guard execution unit 506 controls the throttle opening degree after reducing the upper limit value of the throttle opening degree when the estimated engine torque is larger than the threshold value.

  Specifically, the upper limit guard execution unit 506 decreases the upper limit value of the throttle opening by a value corresponding to the difference between the estimated engine torque and the threshold value. Alternatively, the upper limit guard execution unit 506 may decrease the upper limit value by a predetermined value regardless of the difference between the engine torque and the threshold value.

  Alternatively, the upper limit guard execution unit 506 may gradually decrease the upper limit value until the estimated engine torque becomes equal to or lower than the threshold value. For example, the degree of reduction for each stage is determined in advance. When the estimated engine torque is greater than the threshold value, the upper limit guard execution unit 506 decreases the upper limit value with a degree of decrease corresponding to the stage. If the estimated engine torque is greater than the threshold value after a predetermined time has elapsed since the upper limit value was decreased, the upper limit guard execution unit 506 increases the upper limit with the degree of decrease according to the next stage. Decrease the value. The upper limit guard execution unit 506 stops the decrease of the upper limit value when the estimated engine torque becomes equal to or less than the threshold value.

  In the present embodiment, engine torque estimating unit 500, traveling condition determining unit 502, threshold value determining unit 504, and upper limit guard executing unit 506 are all programs stored in the memory of CPU of engine ECU 280. Although described as functioning as software realized by execution, it may be realized by hardware. Such a program is recorded on a storage medium and mounted on the vehicle.

  Referring to FIG. 5, a control structure of a program executed by engine ECU 280 that is the vehicle control apparatus according to the present embodiment will be described.

  In step (hereinafter step is referred to as S) 100, engine ECU 280 estimates the engine torque based on the MG (1) torque. In S102, engine ECU 280 determines whether or not the traveling state of the vehicle satisfies a predetermined traveling condition. The determination as to whether or not a predetermined traveling condition is satisfied may be made prior to the estimation of engine torque (S100). If the traveling state of the vehicle satisfies a predetermined traveling condition (YES in S102), the process proceeds to S104. Otherwise (NO in S102), this process ends.

  In S104, engine ECU 280 determines whether or not the estimated engine torque is greater than a threshold value. If the estimated engine torque is greater than the threshold value (YES in S104), the process proceeds to S106. Otherwise (NO in S104), this process ends. In S106, engine ECU 280 executes a throttle upper limit guard.

  The operation of engine ECU 280, which is the vehicle control apparatus according to the present embodiment based on the above-described structure and flowchart, will be described with reference to FIGS. The changes in engine torque shown in FIGS. 6 and 7 are examples, and are not limited to such changes.

<When setting the upper guard value according to the difference between the estimated engine torque and the threshold value>
For example, it is assumed that the upper guard value is A (0) and the engine torque is Te (0). Here, A (0) is a value set when the upper limit of the throttle opening is not limited.

  At time T (0), engine torque Te (0) is estimated based on MG (1) torque (S100). When the amount of change in MG (2) rotational speed is equal to or less than a predetermined amount of change and the vehicle traveling state satisfies a predetermined traveling condition (YES in S102), engine torque Te (0) is a threshold value. It is determined whether or not it is larger than Th (0) (S104).

  Since engine torque Te (0) is larger than threshold value Th (0) (YES in S104), throttle upper limit guard is executed (S106). That is, engine ECU 280 limits the upper limit of the opening degree of throttle valve 122E.

  At this time, a value A (1) corresponding to the difference between the engine torque Te (0) and the threshold value Th (0) is set as the upper limit guard value of the throttle valve 122E.

  Further, in the present embodiment, it is assumed that the upper limit guard value A (0) to A (1) changes with a predetermined amount of time change, but is not particularly limited to such a change mode. . For example, the upper limit guard value may be changed from A (0) to A (1) when the engine torque Te (0) is larger than the threshold value Th (0).

  When the opening degree of the throttle valve 122E is limited by decreasing the throttle upper limit guard value from A (0) to A (1), the engine torque generated in the engine 120 decreases. Therefore, at time T (1), the engine torque becomes Te (2), which is smaller than the threshold value Th (0).

<When gradually reducing the upper guard value>
For example, it is assumed that the upper guard value is A ′ (0) and the engine torque is Te ′ (0). Here, A ′ (0) is a value set when the upper limit of the throttle opening is not limited.

  At time T ′ (0), engine torque Te ′ (0) is estimated based on the MG (1) torque (S100). MG (2) When the amount of change in the rotational speed is equal to or less than a predetermined amount of change and the vehicle traveling state satisfies a predetermined traveling condition (YES in S102), engine torque Te ′ (0) is a threshold. It is determined whether or not the value is larger than the value Th (0) (S104).

  Since engine torque Te '(0) is greater than threshold value Th (0) (YES in S104), throttle upper limit guard is executed (S106). That is, engine ECU 280 limits the upper limit of the opening degree of throttle valve 122E.

  At this time, the upper limit guard value of the throttle valve 122E decreases stepwise. Specifically, when the estimated engine torque is greater than threshold value Th (0), engine ECU 280 decreases the upper limit guard value by a predetermined value corresponding to the step and sets A ′ (1). To do.

  The engine ECU 280 decreases the upper limit guard value by a predetermined value until a predetermined time elapses (that is, the time T ′ (1) after the elapse of the predetermined time from the time T ′ (1)). 2)), the opening degree of the throttle valve 122E is controlled with A ′ (1) as the upper limit guard value. At this time, the upper limit of the throttle valve 122E is limited, so that the engine torque changes from Te ′ (0) to Te ′ (1).

  When the estimated engine torque Te ′ (1) is larger than the threshold value Th (0) at time T ′ (2), the upper limit guard value is decreased again by a predetermined value and A ′ (2 ). Engine ECU 280 repeats the decrease in the upper guard value until the engine torque becomes equal to or less than threshold value Th (0). As the degree of restriction on the upper limit of the throttle valve 122E increases, the engine torque changes from Te '(1) to Te' (2) lower than Th (0) at time T '(3).

  As described above, according to the vehicle control apparatus of the present embodiment, it is not necessary to consider individual variations by estimating the engine torque based on the engine torque reaction force in the motor generator. Therefore, it is possible to estimate the engine torque with higher accuracy than when estimating based on the opening degree of the throttle valve and the fuel injection amount. Therefore, the engine torque estimated from the threshold value set based on the allowable torque of the motor generator, the maximum value of the pressure in the cylinder, and the exhaust pressure at which exhaust leakage to the exhaust passage occurs when the exhaust valve is closed By restricting the opening of the throttle valve when is large, it is possible to avoid the restriction of the opening of the throttle valve unnecessarily. Therefore, the engine torque power can be sufficiently exhibited as compared with the case where the engine torque is estimated based on the opening degree of the throttle valve and the fuel injection amount. Therefore, it is possible to provide a vehicle control device and a control method for accurately limiting the opening degree of the throttle valve according to the engine torque.

  Further, by limiting the opening of the throttle valve so that the engine torque becomes equal to or less than the threshold value Th (0), the engine speed increases due to the engine torque exceeding the allowable torque of the motor generator. It is possible to suppress the occurrence of a local high temperature portion due to the maximum pressure value exceeding the allowable value in the engine and the occurrence of exhaust leakage into the exhaust passage when the exhaust valve is closed.

  Further, by gradually decreasing the upper limit value of the throttle opening until the engine torque becomes equal to or less than the threshold value Th (0), the engine speed increases due to the engine torque exceeding the allowable torque of the generator, and the cylinder It is possible to suppress the occurrence of local high temperatures due to the maximum value of the internal pressure exceeding the value allowed in the engine and the occurrence of exhaust leakage into the exhaust passage when the exhaust valve is closed.

  Then, by setting the threshold value so that the engine torque does not exceed the allowable torque of the motor generator, it is possible to prevent the engine speed from blowing up.

  Furthermore, by setting the engine torque threshold value so that the maximum value (Pmax) of the pressure in the cylinder does not exceed an allowable value in the engine, various variations such as manufacturing variations of components and variations in usage conditions are obtained. However, since it can be avoided that the maximum value of the pressure in the cylinder exceeds the value allowed in the engine, deterioration of the durability of the engine can be suppressed.

  By setting an engine torque threshold so as not to generate exhaust pressure that causes exhaust leakage to the exhaust passage when the exhaust valve is closed, the exhaust leakage is suppressed and local high temperature generation is prevented. Can be suppressed. Therefore, deterioration of engine durability can be suppressed.

  In the present embodiment, the estimated engine torque is set by setting the engine torque threshold based on the allowable torque of the generator, Pmax, and the degree of exhaust pressure when exhaust leakage occurs in the closed exhaust valve. In the above description, the upper limit of the throttle valve opening is limited when the threshold value is exceeded, but a threshold value for engine power may be set instead of or in addition to the engine torque. That is, if the estimated engine power is larger than the threshold value, the upper limit of the throttle valve opening may be limited. The engine power is estimated by the product of the estimated engine torque and the current engine speed.

  In particular, Pmax and the exhaust pressure when the exhaust valve is closed are affected by the rotational speed. Therefore, the estimated engine torque is larger than a threshold value set based on the allowable torque of the generator, or the estimated engine power is set based on Pmax and the exhaust pressure when the exhaust valve is closed. If the engine power threshold is greater than the threshold, the upper limit of the throttle valve opening may be limited. In this way, the upper limit of the throttle valve opening can be more accurately limited, so that the upper limit of the throttle valve opening is not unnecessarily limited.

  Further, in the present embodiment, the description has been made assuming that the engine torque is estimated when the traveling state of the vehicle satisfies a traveling condition such as a steady traveling state or a fully open traveling state. When the engine power calculated from the engine torque and the engine speed is greater than a predetermined value (for example, an upper limit value at which exhaust leakage does not occur when the exhaust valve is closed), the running state of the vehicle is predetermined. The travel conditions may be satisfied.

Further, in the present embodiment, the engine torque is the threshold value Th when the upper limit guard is executed.
Although the upper limit guard value is set to be smaller than (0), the upper limit guard value may be set so that the engine power is smaller than the threshold value.

  Further, in the present embodiment, it is determined whether or not the estimated torque is larger than the threshold value when a predetermined traveling condition is satisfied. For example, at least the estimated torque is reduced. When the upper limit guard is executed when the threshold value is larger than the threshold value and the predetermined driving condition is not satisfied, a value set when the upper limit of the throttle opening is not limited may be selected. .

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a control block diagram which shows the structure of the hybrid vehicle in this Embodiment. It is a nomograph (the 1) of a power split mechanism. It is a functional block diagram of an engine ECU that is a control device for a vehicle according to the present embodiment. It is a collinear diagram of the power split mechanism (part 2). It is a flowchart which shows the control structure of the program performed by engine ECU which is a control apparatus of the vehicle which concerns on this Embodiment. It is a timing chart (the 1) which shows operation | movement of engine ECU which is a control apparatus of the vehicle which concerns on this Embodiment. It is a timing chart (the 2) which shows operation | movement of engine ECU which is a vehicle control apparatus which concerns on this Embodiment.

Explanation of symbols

  120 engine, 122 intake passage, 122A air cleaner, 122B air flow meter, 122C electronic throttle, 122D throttle position sensor, 122E throttle valve, 124 exhaust passage, 124A air fuel ratio sensor, 124B three-way catalytic converter, 124C catalyst temperature sensor, 124D silencer , 124E oxygen sensor, 126 cylinder, 128 intake valve, 130 exhaust valve, 140 motor generator, 140A generator, 140B motor, 160 drive wheel, 180 reducer, 200 power split mechanism, 220 battery for running, 240 inverter, 242 converter, 260 battery ECU, 280 engine ECU, 300 MG_ECU, 320 HV_ECU, 380 crank position sensor, 00 the engine torque estimating unit, 502 traveling condition determination section, 504 threshold determination unit, 506 upper limit guard execution unit.

Claims (14)

A control device for a vehicle, wherein the vehicle includes an engine and a motor generator coupled to an output shaft of the engine, and the engine includes a cylinder, an exhaust passage for exhausting gas in the cylinder, and the exhaust An exhaust valve provided between the passage and the cylinder, and a throttle valve for adjusting the flow rate of the gas introduced into the cylinder,
Estimating means for estimating an engine torque based on a torque reaction force of the engine in the motor generator;
Reducing means for reducing the upper limit value of the opening of the throttle valve when the engine torque is greater than a threshold value,
The threshold value is at least one of an allowable torque of the motor generator, a maximum pressure value in the cylinder, and an exhaust pressure at which exhaust leakage into the exhaust passage occurs when the exhaust valve is closed. The vehicle control device is set based on the above.   2. The reducing means reduces an upper limit value of the throttle valve opening by a value corresponding to a difference between the engine torque and the threshold value so that the engine torque becomes equal to or less than the threshold value. The vehicle control device described in 1.   3. The vehicle control device according to claim 1, wherein the reducing means decreases the upper limit value of the opening degree of the throttle valve stepwise until the engine torque becomes equal to or less than the threshold value.   The vehicle control device according to any one of claims 1 to 3, wherein the estimating means estimates the engine torque when a traveling state of the vehicle satisfies a predetermined traveling condition.   The vehicle control device according to claim 1, wherein the threshold value is set so that the engine torque does not exceed an allowable torque of the motor generator.   The vehicle control device according to claim 1, wherein the threshold value is set so that a maximum value of pressure in the cylinder does not exceed a value allowed in the engine.   The vehicle control device according to any one of claims 1 to 6, wherein the threshold value is set so as not to generate an exhaust pressure that causes an exhaust leak to the exhaust passage when the exhaust valve is closed. . A control method for a vehicle, wherein the vehicle includes an engine and a motor generator coupled to an output shaft of the engine, and the engine includes a cylinder, an exhaust passage for exhausting gas in the cylinder, and the exhaust An exhaust valve provided between the passage and the cylinder, and a throttle valve for adjusting the flow rate of the gas introduced into the cylinder,
Estimating an engine torque based on a torque reaction force of the engine in the motor generator;
Reducing the upper limit value of the throttle valve opening when the engine torque is greater than a threshold value,
The threshold value is at least one of an allowable torque of the motor generator, a maximum pressure value in the cylinder, and an exhaust pressure at which exhaust leakage into the exhaust passage occurs when the exhaust valve is closed. The vehicle control method is set based on the above.   The step of reducing the upper limit value decreases the upper limit value of the throttle valve opening by a value corresponding to the difference between the engine torque and the threshold value so that the engine torque becomes equal to or less than the threshold value. The vehicle control method according to claim 8.   The vehicle control method according to claim 8 or 9, wherein the step of decreasing the upper limit value decreases the upper limit value of the throttle valve opening stepwise until the engine torque becomes equal to or less than the threshold value.   The vehicle control method according to claim 8, wherein the step of estimating the engine torque estimates the engine torque when a traveling state of the vehicle satisfies a predetermined traveling condition.   12. The vehicle control method according to claim 8, wherein the threshold value is set so that the engine torque does not exceed an allowable torque of the motor generator.   The vehicle control method according to claim 8, wherein the threshold value is set so that a maximum value of pressure in the cylinder does not exceed a value allowed in the engine.   The vehicle control method according to any one of claims 8 to 13, wherein the threshold value is set so as not to generate an exhaust pressure that causes an exhaust leak to the exhaust passage when the exhaust valve is closed. .

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