JP5724289B2 - Control device for hybrid vehicle - Google Patents

Description

  The present invention relates to a technique for preventing abnormal noise when an ignition is turned off in a control device for a hybrid vehicle.

  In a hybrid vehicle that drives a vehicle using the power of at least one of an internal combustion engine (engine) and a motor, a structure in which the power of the engine and the motor is intermittently connected to a drive shaft by a friction engagement element (clutch) is known.

  In such a structure, when a request for stopping the internal combustion engine is made during operation of the internal combustion engine with the frictional engagement element engaged in the non-traveling range, the hybrid vehicle is configured to stop the internal combustion engine and perform slip control of the engagement element. A control apparatus (see Patent Document 1) is known.

JP 2009-208700 A

  When the motor is driven in the power generation mode by the engine while the vehicle is stopped, the clutch cannot be released if the battery capacity is so small that the engine cannot be restarted. In addition, when the engine and the motor are stopped simultaneously, the power generation torque of the motor decreases more responsively than the engine, which may cause the engine to blow up due to a response delay, causing vibration and noise .

  The present invention has been made in view of such problems, and an object thereof is to prevent generation of vibrations and abnormal noise from the engine when the ignition is off.

  One embodiment of the present invention is applied to a control device that controls the operation of an engine and a motor generator of a hybrid vehicle that travels by the driving force of an engine or a motor generator and operates the motor generator as a generator and can be stored in a battery. The

When the motor generator is operated as a generator by the driving force of the engine while the vehicle is stopped, the controller stops the fuel supply to the engine after reducing the engine driving torque to a preset engine stoppable torque Engine stop means for stopping the operation of the engine, the engine stop means, when stopping the engine based on the engine stop command, the engine stop possible torque, based on the rotational torque of the motor generator during power generation , When the fuel supply to the engine is stopped, the engine speed is set to a value that does not increase, and after the engine drive torque is reduced to the engine stoppable torque, the fuel supply to the engine is stopped and at the same time Stop generator operation.

According to the present invention, when the engine and the motor are stopped at the same time , the engine is stopped after the engine drive torque is reduced to the engine stop torque. It is possible to prevent abnormal noise and vibration generated by the compression reaction force of the cylinder internal pressure of the engine.

It is a block diagram of an example of the power train of the hybrid vehicle of embodiment of this invention. 1 is a configuration block diagram of a hybrid system according to an embodiment of the present invention. It is a flowchart of the engine stop process of embodiment of this invention. It is a time chart of the engine stop process of embodiment of this invention. It is a block diagram of the other example of the power train of the hybrid vehicle of embodiment of this invention. It is a block diagram of the other example of the power train of the hybrid vehicle of embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a configuration diagram of a power train of a hybrid vehicle according to a first embodiment of the present invention. As shown in FIGS. 5 and 6, the configuration of the power train of the hybrid vehicle, in particular, the position of the second clutch 5 is not limited to that shown in FIG.

  In the power train of the hybrid vehicle shown in FIG. 1, an engine 1 that is a driving force source as an internal combustion engine and a motor generator 2 that generates driving force by electric power are arranged in series in the traveling direction of the vehicle. These driving forces are shifted by the automatic transmission 3 and output to the drive wheels 7 via the differential gear 6.

  The motor generator 2 acts as a motor to generate driving force, or acts as a generator to generate electric power.

  A crankshaft (output shaft) 1 a of the engine 1 and an input shaft 2 a of the motor generator 2 are connected via a first clutch 4. The output shaft 2 b of the motor generator 2 is connected to the input shaft 3 a of the automatic transmission 3. A differential gear 6 is connected to the output shaft 3 b of the automatic transmission 3.

  The automatic transmission 3 selectively engages and disengages a plurality of friction elements (such as a clutch and a brake), and selects a transmission path by a combination of these friction elements to determine a gear position. Therefore, the automatic transmission 3 shifts the rotation from the input shaft 3a to a gear ratio corresponding to the selected gear position, and outputs it to the output shaft 3b.

  The automatic transmission 3 uses one of the plurality of friction elements as the second clutch 5. The automatic transmission 3 combines the power of the engine 1 input via the first clutch 4 and the power input from the motor generator 2 and outputs the combined power to the drive wheels 7.

  The first clutch 4 is configured by, for example, a dry clutch whose engagement state is controlled by hydraulic pressure. The second clutch is configured by a wet multi-plate clutch whose capacity is controlled by hydraulic pressure. In addition, all may be comprised by the dry-type clutch or the wet multi-plate clutch.

  The first clutch 4 includes a stroke sensor 23 that detects the stroke amount of the first clutch 4.

  The output shaft 1 a of the engine 1 includes an engine rotation speed sensor 10 that detects the rotation speed Ne of the engine 1. The input shaft 2 a of the motor generator 2 includes a motor generator rotational speed sensor 11 that detects the rotational speed Nm of the motor generator 2.

  The automatic transmission 3 includes an automatic transmission input shaft rotational speed sensor 12 that detects an input shaft rotational speed Ni of the automatic transmission 3, and an automatic transmission output shaft rotational speed that detects an output shaft rotational speed No of the automatic transmission 3. A sensor 13.

  The signals output by these sensors are output to the integrated controller 20 described later with reference to FIG.

  The power train of the hybrid vehicle configured as described above has three travel modes according to the engaged state of the first clutch 4. The first travel mode is an electric travel mode (hereinafter referred to as “EV mode”) in which the first clutch 4 is in the released state and travels only with the power of the motor generator 2.

  The second travel mode is a hybrid travel mode (hereinafter referred to as “HEV mode”) in which the first clutch 4 is engaged and travel is performed using the power of both the engine 1 and the motor generator 2.

  The third traveling mode is a slip traveling mode (hereinafter referred to as “WSC (Wet Start Clutch) mode) in which the first clutch 4 is engaged and the second clutch 5 is slip-controlled to travel with the power of the engine 1 and the motor generator 2. "). The WSC mode realizes creep running particularly when the battery SOC is low or the engine water temperature is low. Further, in this mode, the driving force can be output while starting the engine 1 when the engine 1 starts from a stopped state.

  The HEV mode includes an “engine running mode”, a “motor assist running mode”, and a “running power generation mode”.

  The engine travel mode is a mode for driving the drive wheels 7 using only the engine 1 as a drive source. The motor assist travel mode is a mode in which both the engine 1 and the motor generator 2 travel using the drive sources. The traveling power generation mode is a mode in which the motor generator 2 is caused to function as a generator by the driving force of the engine 1 while traveling with the engine 1 as a drive source.

  Further, as a further mode, there is a power generation mode in which the motor generator 2 functions as a generator by the driving force of the engine 1 when the vehicle is stopped.

  The integrated controller 20 controls the engine 1, the motor generator 2, the first clutch 4, the second clutch 5, etc., and switches the traveling mode.

  FIG. 2 is a configuration block diagram of a hybrid system including a control device.

  The hybrid system includes an integrated controller 20, an engine controller 21, a motor generator controller 22, an inverter 8, a battery 9, and the like.

  The integrated controller 20 receives signals from the engine rotational speed sensor 10, the motor generator rotational speed sensor 11, the automatic transmission input shaft rotational speed sensor 12, the automatic transmission output shaft rotational speed sensor 13, and the stroke sensor 23. In addition, signals from the accelerator opening sensor 17 that detects the accelerator opening APO (= actual accelerator opening rAPO) and the SOC sensor 16 that detects the state of charge of the battery 9 are input.

  The integrated controller 20 determines the operating point of the powertrain according to the accelerator opening APO, the battery state of charge SOC, and the vehicle speed VSP (proportional to the automatic transmission output shaft rotational speed No), and the driving force desired by the driver Select a driving mode that can realize In addition, the motor generator controller 22 is commanded with a target motor generator torque or a target motor generator rotation speed. Further, the target engine torque is designated to the engine controller 21. In addition, a drive signal is commanded to the solenoid valve 14 that controls the hydraulic pressure of the first clutch 4 and the solenoid valve 15 that controls the hydraulic pressure of the second clutch 5.

  The engine controller 21 controls the engine 1 so that the engine torque becomes the target engine torque.

  The motor generator controller 22 controls the motor generator 2 via the battery 9 and the inverter 8 so that the torque of the motor generator 2 becomes the target motor generator torque (or the rotational speed of the motor generator becomes the rotational speed of the target motor generator). Control. When the motor generator 2 is used as a generator, the power generation torque of the motor generator is controlled so that the motor generator 2 becomes the target power generation torque.

  The inverter 8 converts the electric power of the battery 9 into a high frequency current and supplies it to the motor generator 2. Further, when the motor generator 2 is in a power generation state, the generated power is converted into a direct current to charge the battery 9.

  Next, the operation at the time of ignition off in the hybrid vehicle configured as described above will be described.

  If the driver requests ignition off while the vehicle is stopped, the integrated controller 20 stops the operation of the engine 1 and the motor generator 2 to stop the power train.

  By the way, when the first clutch 4 is engaged and the motor generator 2 is rotated by the driving force of the engine 1 to generate power (power generation mode), the following situation may occur due to the ignition off.

  When the engine 1 is driving the motor generator 2 to generate electric power, and the ignition off is requested, when the electric power generation of the motor generator 2 is stopped, the generated torque decreases with good response. On the other hand, when the engine 1 is in the driving state, the fuel is first cut by the ignition off, the driving torque is reduced, and then the rotation is gradually reduced.

  At this time, since the responsiveness at which the motor generator 2 stops is faster than the responsiveness at which the engine 1 stops, the load decreases rapidly before the engine 1 stops due to a decrease in power generation torque, and the rotation of the engine 1 blows. There is a possibility of going up.

  In addition, when the fuel cut is performed before the driving torque of the engine 1 is reduced, the compression reaction force of the cylinder internal pressure of the engine 1 increases, and when the rotational speed of the engine 1 gradually decreases, it passes through the resonance band. There is a possibility that vibration and abnormal noise occur in the engine 1.

  At this time, a method of separating the torque between the engine 1 and the motor generator 2 by controlling the first clutch 4 to the slip state is also conceivable. However, for example, when the SOC of the battery 9 is significantly reduced, it is necessary to always connect the engine 1 and the motor generator 2 directly in order to continue power generation, and this method cannot be employed.

  Therefore, in the embodiment of the present invention, the following configuration is used to prevent the vibration of the engine 1 and the generation of abnormal noise when the ignition is off.

  FIG. 3 is a flowchart of the engine stop process executed by the integrated controller 20 according to the embodiment of this invention. Note that the processing of this flowchart is executed by the integrated controller 20 at a predetermined interval (for example, 10 ms).

  The integrated controller 20 determines whether or not an ignition off operation has been performed by the driver and an ignition off has been requested. When the ignition off operation is not performed, the process proceeds to step S6.

  If it is determined that the ignition off operation has been performed, the process proceeds to step S2. The integrated controller 20 determines whether or not the first clutch 4 is in the engaged state and the motor generator 2 is generating power, that is, whether or not the power generation mode is when the vehicle is stopped. If it is not the stop-time power generation mode, the process proceeds to step S6.

  If it is determined that the power generation mode is when the vehicle is stopped, the process proceeds to step S3, and the integrated controller 20 starts an engine torque reduction process for reducing the drive torque of the engine 1. Specifically, the engine controller 21 sets the target drive torque of the engine 1 to the engine stoppable torque, and reduces the drive torque of the engine 1. The engine stoppable torque will be described later.

  Next, the integrated controller 20 determines whether or not the driving torque of the engine 1 has reached the engine stoppable torque.

  Specifically, in step S4, it is determined whether or not the drive torque of the engine 1 is equal to or greater than the stoppable torque. When the driving torque of the engine 1 is less than the stoppable torque, the process proceeds to step S6. If the driving torque of the engine 1 is equal to or greater than the stoppable torque, the process proceeds to step S5, and a timer for waiting until a predetermined time elapses from the start of the engine torque reduction process is started. If the timer expires after a predetermined time has elapsed from the start of the engine torque reduction process, the process proceeds to step S6, and ignition off is permitted.

  In step S6, the integrated controller 20 permits ignition off. Specifically, when the driver has already requested ignition off, processing such as stopping the engine 1 and stopping the power generation of the motor generator 2 is performed, and the operation of the power train is stopped.

  By such a process, when the ignition off operation is performed in the power generation mode when the vehicle is stopped, it is possible to prevent the engine 1 from blowing up, generating vibrations and abnormal noise.

  The engine stoppable torque set in step S3 is set as follows.

  In the embodiment of the present invention, when the ignition-off is requested, the driving torque of the engine 1 is reduced to the engine stopable torque before the engine 1 is stopped in order to prevent the engine 1 from blowing up or noise due to vibration. Reduce.

  The engine 1 drives a motor generator 2 that is generating power. Therefore, when the motor generator 2 stops the power generation, the generated torque is lost, and the engine stoppable torque is set to a torque that can prevent the load on the engine 1 from rapidly decreasing and the engine 1 from blowing up.

  The engine stoppable torque is set based on, for example, a dynamic friction coefficient (friction) between the engine 1 and the motor generator 2. If the friction is small, the rate of decrease in the rotational speed of the engine 1 is small. Therefore, the engine stoppable torque is set small to prevent the engine from blowing up.

  The friction is calculated based on the mass of the rotating part of the engine 1 and the motor generator 2 and the friction coefficient of the bearings. Furthermore, in addition to friction, inertia when the engine 1 and the motor generator 2 are operating may be calculated and set based on these friction and inertia.

  Further, if the fuel cut is performed in a state where the driving torque of the engine 1 is large, the compression reaction force due to the cylinder internal pressure is increased by the inertia, so that the vibration due to passing through the resonance band of the engine 1 is increased. Therefore, the engine stoppable torque of the engine 1 is set so that the compression reaction force due to the cylinder internal pressure does not pass through the resonance band of the engine 1.

  In this case, the compression reaction force is not necessarily small. In order to prevent the occurrence of knocking or the like, the fuel supply amount is made larger than the minimum fuel supply amount that can be supplied to the engine 1, and the driving torque at that time is set as the engine stoptable torque.

  Further, the engine stoppable torque may be set by the power generation torque of the motor generator 2 that is generating power. The driving torque of the engine 1 is calculated relative to the target driving torque by the engine rotation speed, the fuel supply amount, the exhaust gas oxygen amount, and the like. On the other hand, since the power generation torque of the motor generator 2 can be easily calculated from the amount of power generation, the accuracy is high. When the first clutch 4 is in the engaged state, the driving torque of the engine 1 is substantially equal to the power generation torque of the motor generator 2.

  Therefore, the engine stoppable torque is set based on the power generation torque of the motor generator 2.

  Specifically, assuming that the engine 1 is blown up when the power generation torque is suddenly reduced, the power generation torque is calculated so that the engine 1 does not blow up, and this power generation torque is set as the engine stoppable torque. Further, as described above, the engine stoppable torque at this time may be set to be larger than the minimum amount of fuel that can be supplied to the engine 1 and the drive torque at that time may be set as the engine stoppable torque. Good.

  Further, the predetermined time of the timer set in the above-described step S5 is set to a time during which the engine 1 can be sufficiently reduced to the engine stoppable torque. If this timer is set for a long time, there is a possibility that the driver who has performed the ignition off operation may feel uncomfortable. Therefore, the maximum time of this timer is 1 second.

  FIG. 4 is a time chart of the engine stop process according to the embodiment of the present invention.

  As described above, when it is determined that the ignition off operation has been performed in the stop-time power generation mode (Yes in step S1 in FIG. 3 and Yes in step S2), the integrated controller 20 starts the engine torque reduction process.

  In the engine torque reduction process, the integrated controller 20 sets the target torque of the engine 1 to the engine stoppable torque and reduces the drive torque of the engine 1. Further, a timer for determining whether a predetermined time has elapsed since the start of the engine torque reduction process is operated.

  After that, when the drive torque of the engine 1 falls below the stoppable torque (No in step S4 in FIG. 3), or when a predetermined time has elapsed from the start of the engine torque reduction process (Yes in step S5 in FIG. 3). The integrated controller 20 permits ignition off (step S6 in FIG. 3).

  With the ignition off permission, the integrated controller 20 performs engine stop control such as cutting off the supply of fuel to the engine 1. The engine 1 then stops.

  As described above, the embodiment of the present invention travels by the driving force of the driving source including the engine 1 or the motor generator 2 and operates the motor generator 2 as a generator by the driving force of the engine or the regenerative power of the vehicle. 9 is applied to a hybrid vehicle capable of storing electricity.

  When the motor generator 2 is rotated by the driving force of the engine 1 to generate power (power generation mode), the ignition is not immediately turned off when the driver performs an ignition off operation. The driving torque of the engine 1 is reduced to a torque at which the engine can be stopped, or the ignition is turned off after waiting for a predetermined time to expire by a timer.

  Thereby, generation | occurrence | production of the noise by the engine surging generated by the power generation torque of the motor generator 2 reducing previously with respect to the drive torque of the engine 1 can be prevented. In addition, when the engine 1 is stopped with a high driving torque, it is possible to prevent the generation of noise due to vibrations that occur when the cylinder internal pressure is high and the compression reaction force passes through the resonance band of the engine 1.

  The engine stoppable torque is set to a torque that prevents the engine 1 from blowing up when the fuel of the engine 1 is cut. For example, it is set based on the dynamic friction coefficient (friction) between the engine 1 and the motor generator 2. Furthermore, in addition to friction, inertia when the engine 1 and the motor generator 2 are operating may be calculated and set based on these friction and inertia. Thereby, since the engine 1 is prevented from being blown up when the fuel of the engine 1 is cut, vibrations and abnormal noise caused by the engine 1 being blown up can be prevented.

  In addition, the engine stoppable torque of the engine 1 is set to such an extent that the compression reaction force due to the cylinder internal pressure does not pass through the resonance band of the engine 1 due to the fuel cut of the engine 1. In this case, the fuel supply amount is made larger than the minimum fuel supply amount that can be supplied to the engine 1, and the driving torque at that time is set as the engine stoppable torque. Thereby, the vibration by passing through the resonance band of the engine 1 by the compression reaction force by the cylinder internal pressure can be prevented.

  Further, the engine stoppable torque is set based on the power generation torque of the motor generator 2 during power generation. Specifically, assuming that the engine 1 is blown up when the power generation torque is suddenly reduced, the power generation torque is calculated so that the engine 1 does not blow up, and this power generation torque is set as the engine stoppable torque. Further, as described above, the engine stoppable torque at this time may be set to be larger than the minimum amount of fuel that can be supplied to the engine 1 and the drive torque at that time may be set as the engine stoppable torque. Good. Since the power generation torque can be calculated with higher accuracy than the driving torque, it is possible to set the timing for performing the fuel cut of the engine 1 to an optimal timing, thereby preventing abnormal noise and vibrations and improving fuel consumption.

  Since the predetermined time of the timer is 1 second, the driver does not feel uncomfortable.

DESCRIPTION OF SYMBOLS 1 Engine 2 Motor generator 4 1st clutch 5 2nd clutch 20 Integrated controller

Claims (10)

In a hybrid vehicle that travels by the driving force of an engine or a motor generator and operates the motor generator as a generator and can be stored in a battery, the control device controls the operation of the engine and the motor generator,
When the motor generator is operated as a generator by the driving force of the engine while the vehicle is stopped, the fuel supply to the engine is stopped after the engine driving torque is reduced to a preset engine stopping torque And an engine stop means for stopping the operation of the engine,
The engine stop means is
When stopping the engine based on the engine stop command,
The engine stoppable torque is set to a value at which the rotational speed of the engine does not rise when the supply of fuel to the engine is stopped based on the rotational torque of the motor generator during power generation ,
The hybrid vehicle control device characterized in that after the drive torque of the engine is reduced to the engine stoppable torque, the fuel supply to the engine is stopped and at the same time the operation of the motor generator is stopped. . The hybrid vehicle control device according to claim 1, wherein the engine stoppable torque is set based on dynamic friction coefficients of the engine and the motor generator . 3. The hybrid vehicle according to claim 1, wherein the engine stoppable torque is set based on a dynamic friction coefficient of the engine and the motor generator and an inertia of the engine and the motor generator . Control device. 2. The engine stoppable torque is set to a torque that does not pass through a resonance band of the engine due to a compression reaction force caused by an internal cylinder pressure of the engine when fuel supply to the engine is stopped. The control apparatus of the hybrid vehicle described in 2 . The hybrid vehicle control device according to claim 4, wherein the engine stoppable torque is the torque and is equal to or greater than a minimum value of fuel that can be supplied to the engine . The engine stoppable torque is such that the rotational torque of the motor generator during power generation is such that the rotational speed does not fluctuate due to the compression reaction force due to the cylinder internal pressure of the engine when the supply of fuel to the engine is stopped. The hybrid vehicle control device according to claim 1, wherein the control device is set. The engine stoppable torque is a lower limit value of the torque at which the rotational speed does not fluctuate due to a compression reaction force due to the cylinder internal pressure of the engine when the supply of fuel to the engine is stopped, and can be supplied to the engine The hybrid vehicle control device according to claim 6, wherein the torque is equal to or greater than a torque according to a minimum value of fuel . The engine stop means stops the fuel supply to the engine and stops the operation of the engine after reducing the engine drive torque to a preset engine stoppable torque when an ignition off is requested. The control apparatus for a hybrid vehicle according to claim 1, wherein The engine stop means stops the operation of the engine by stopping fuel supply to the engine after a predetermined engine stop timer expires after an ignition off is requested. The hybrid vehicle control apparatus described . The engine stop means stops the operation of the engine by stopping fuel supply to the engine after a predetermined engine stop timer expires after the ignition off is requested, and the engine stop timer The control device for a hybrid vehicle according to claim 8 or 9, wherein the control device is set within a range .

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