JP2013112265A - Engine stop control apparatus for hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine stop control apparatus for hybrid vehicle in which engine starting performance can be improved in subsequent automatic start by discriminating a crank angle of the engine through a motor control system without inputting crank angle information from an engine control system, and stopping the engine at an optimal crank position by applying brake in more suitable timing through a traveling motor in automatic engine stop.SOLUTION: When automatically stopping an engine 2, a clutch 4 is connected, fuel supply of an engine 2 is stopped, a motor 6 is driven thereafter and as regeneration control, rotation control is executed for maintaining a rotation speed of the motor 6 at a predetermined target value. At such a time, a peak of a varying waveform is specified while defining as an index a regeneration rate of the motor 6 varying synchronously to torque variation of the engine 2, and an optimal crank position is discriminated on the basis of a stop crank angle Δθstop which is preset as a crank angle to an optimal crank position from the peak point. At a time point when the engine 2 reaches the optimal crank position, the motor torque is increased, and the engine 2 is braked and stopped.

Description

  The present invention relates to an engine stop control device for a hybrid vehicle, and more particularly to an engine stop control device that stops an engine at a crank position that is optimal for starting when a predetermined engine stop condition is satisfied.

In recent years, for the purpose of reducing fuel consumption and reducing CO ₂ emissions, the engine is automatically stopped when a predetermined stop condition is satisfied, such as waiting for a signal, and then the engine is automatically started when the predetermined start condition is satisfied. Vehicles equipped with an idle stop start function are in widespread use (see, for example, Patent Document 1).
In the vehicle described in Patent Document 1, the engine is started by directly supplying fuel into the cylinder of the cylinder stopped in the expansion process and igniting / combusting it without using a starter motor at the time of automatic engine start. Yes. In order to ignite and burn fuel in the expansion process cylinder, it is necessary to maintain appropriate compression, and for this purpose, it is necessary to stop the piston of any cylinder at an appropriate position in the expansion process when the engine is stopped. Therefore, when the fuel supply is stopped to stop the engine automatically, the generator is braked by controlling the power generation current of the alternator, and the optimal crank position is taken into account the ignition and combustion of the expansion process cylinder. In order to stop the engine.

JP 2005-315202 A

In the vehicle described in the above-mentioned Patent Document 1, it is necessary to stop the engine at the optimal crank position because a specific engine starting method is adopted. For example, a normal vehicle that starts the engine with a starter motor or a traveling motor is used. An optimum crank position also exists in a hybrid vehicle that functions as a starter motor and starts the engine. That is, in these vehicles, the startability of the engine, and hence the required start time and the motor power consumption differ depending on from which crank position cranking is started. Therefore, when the engine is automatically stopped, it is desirable to stop the engine at an optimum crank position in consideration of the subsequent startability. For this purpose, the technique of Patent Document 1 can be applied.
Since the hybrid vehicle is equipped with a traveling motor, it is conceivable to regeneratively control the traveling motor to brake the engine as a substitute for the alternator of Patent Document 1. In order to stop the engine during inertial rotation at the optimum crank position, it is necessary to apply braking by the traveling motor at an appropriate timing using the crank angle information of the engine as an index.

However, the engine control system and the motor control system of the hybrid vehicle are basically independent, and the motor control system does not handle the crank angle information of the engine because it is originally unnecessary. In addition, it is not practical to change the specification so that crank angle information with a large amount of information is input from the engine control system to the motor control system because the processing load becomes excessive. For this reason, simply applying the technique of Patent Document 1 cannot properly control the braking timing of the traveling motor, and as a result, the engine cannot be stopped at the optimum crank position, and thus cannot be implemented.
The present invention has been made to solve such problems, and the object of the present invention is to enable determination of the crank angle of the engine in the motor control system without inputting crank angle information from the engine control system. Engine stop control for hybrid vehicles that can stop the engine at the optimal crank position by applying braking at an appropriate timing by the traveling motor when the engine is automatically stopped, thus improving the engine startability at the subsequent automatic start To provide an apparatus.

  In order to achieve the above object, the invention according to claim 1 is configured to transmit the driving force of an engine and a motor as a driving source of a vehicle to driving wheels via a transmission, and a predetermined stop condition is satisfied. The engine is automatically stopped by stopping the fuel supply to the engine, and then the engine is automatically started when a predetermined start condition is satisfied. The engine is automatically stopped by the idle stop start control means. In a hybrid vehicle control device capable of arbitrarily applying torque by regenerative control of the motor to the engine after stopping fuel supply, when the engine is automatically stopped, the rotation speed of the motor is set to a predetermined value as regenerative control. Rotation control execution means for executing rotation control to maintain the target value, and engine by rotation control of the rotation control execution means The peak specifying means for specifying the peak of the regenerative state of the motor that fluctuates in synchronization with the torque fluctuation, and the peak of the regenerative state specified by the peak specifying means as the starting point after the preset stop crank angle has elapsed Optimal crank position determining means for determining whether or not the engine has reached the optimal crank position, and when it is determined by the optimal crank position determining means that the engine has reached the optimal crank position, the motor torque is increased to And a torque increase control means for applying braking.

  The invention of claim 2 comprises a time conversion means for converting the stop crank angle into a stop time based on the rotational speed of the engine when the peak of the motor regeneration state is specified by the peak specifying means in claim 1, The optimal crank position determining means determines that the engine has reached the optimal crank position when the stop time converted by the time converting means has elapsed from the specified peak.

As described above, according to the engine stop control device of the hybrid vehicle of the first aspect of the present invention, the rotation control is executed as the motor regeneration control when the engine is automatically stopped, so that the motor is synchronized with the fluctuation of the engine torque. Fluctuate the regenerative state, identify the peak of the regenerative state fluctuation at this time, determine the optimal crank position after the predetermined stop crank angle has elapsed from the peak, and when the engine reaches the optimal crank position The motor torque was increased to brake the engine and stop it.
Therefore, the crank angle of the engine can be determined without inputting crank angle information having a large amount of information from the engine control system that controls the engine. Therefore, the engine during inertial rotation can be braked by the motor at an appropriate timing corresponding to the optimum crank position and stopped near the optimum crank position, thereby improving the engine startability at the subsequent automatic start. Can do.

According to the engine stop control device for a hybrid vehicle of a second aspect of the invention, in addition to the first aspect, the stop crank angle is converted into a stop time based on the engine rotation speed when the peak of the motor regeneration state is specified, and the stop It was determined that the engine reached the optimal crank position when time passed.
Even if the stop crank angle is the same depending on the difference in engine speed at the time of peak identification, the optimal crank position will fluctuate.However, by converting the stop crank angle to time, it is always possible regardless of the engine speed at the time of peak identification. The optimum crank position can be accurately determined. Therefore, the engine at the time of automatic stop can be stopped more reliably near the optimum crank position.

1 is an overall configuration diagram illustrating an engine stop control device for a hybrid vehicle according to an embodiment. It is a flowchart which shows the motor braking control routine which inverter ECU performs. It is a time chart which shows the braking state by the motor at the time of making an engine stop automatically.

Hereinafter, an embodiment of an engine stop control device for a hybrid vehicle embodying the present invention will be described.
FIG. 1 is an overall configuration diagram showing an engine stop control device for a hybrid vehicle according to the present embodiment.
The hybrid vehicle 1 is configured as a so-called parallel type hybrid truck. An input shaft of a clutch 4 is connected to an output shaft of a diesel engine (hereinafter referred to as an engine) 2, and a traveling motor 6 (for example, a permanent magnet type synchronous motor) capable of generating power is connected to the output shaft of the clutch 4. The input shaft of the automatic transmission 8 is connected via a rotating shaft (hereinafter referred to as a motor). The automatic transmission 8 automates the connection / disconnection operation of the clutch 4 and the switching operation of the shift stage based on a general manual transmission. However, the type of transmission is not limited to this, and can be arbitrarily changed. For example, a manual transmission or a planetary gear type transmission equipped with a torque converter may be applied.

The output shaft of the transmission 8 is connected to the left and right drive wheels 16 via a propeller shaft 10, a differential 12 and a drive shaft 14. Accordingly, when the clutch 4 is disengaged, only the motor 6 is connected to the drive wheel 16 side via the transmission 8, and when the clutch 4 is connected, both the engine 2 and the motor 6 are connected to the drive wheel 16 side via the transmission 8. The
The motor 6 operates when the DC power stored in the traveling battery 18 is converted into AC power by the inverter 20 and supplied, and the drive torque is appropriately shifted by the transmission 8 and then transmitted to the drive wheels 16. The vehicle 1 is made to travel. Further, during coasting operation in which the vehicle 1 decelerates when the accelerator is off, the motor 6 operates as a generator to generate AC power, and the vehicle 1 is decelerated while generating braking torque on the drive wheels 16 by generating regenerative torque. Let Then, the generated AC power is converted into DC power by the inverter 20 and then charged to the battery 18, whereby the deceleration energy of the vehicle 1 is recovered as electric energy, and then effectively used for traveling by the motor 6. .

  On the other hand, the driving force of the engine 2 is transmitted to the transmission 8 via the rotating shaft of the motor 6 when the clutch 4 is connected, and is transmitted to the drive wheels 16 after being appropriately shifted. Therefore, when the driving force of the engine 2 is transmitted to the driving wheels 16, when the motor 6 is not operated, only the driving force of the engine 2 is transmitted to the driving wheels 16 via the transmission 8 and when the motor 6 is operated. Both the driving forces of the engine 2 and the motor 6 are transmitted to the drive wheels 16 via the transmission 8.

When the remaining capacity (SOC: State Of Charge) of the battery 18 decreases and the battery 18 needs to be charged, the motor 6 operates as a generator even when the vehicle 1 is running, and the engine driving force is reduced. Power is generated using the unit, and the generated AC power is converted into DC power by the inverter 20 and the battery 18 is charged.
The vehicle ECU 22 drives an actuator (not shown) according to information from the operation state of the vehicle 1, the engine 2, and the motor 6, the information from the engine ECU 24 (corresponding to the engine control system), the inverter ECU 26 (corresponding to the motor control system), and the battery ECU 28. Control is performed to control connection / disengagement of the clutch 4 and shift control of the transmission 8, and the engine 2 and the motor 6 are appropriately operated according to these control states and various operation states such as start, acceleration, and deceleration of the vehicle 1. Integrated control to do.

In order to perform such control, the vehicle ECU 22 includes an accelerator sensor 32 that detects the operation amount Acc of the accelerator pedal 30, a vehicle speed sensor 34 that detects the speed V of the vehicle 1, and a motor that detects the rotational speed Nm of the motor 6. Various sensors such as a rotation speed sensor 36 and a brake sensor 40 for detecting a depression operation of the brake pedal 39 are connected. Based on the detection information of these sensors, the required torque required for traveling of the vehicle 1 is calculated in the vehicle ECU 22 and this required torque is distributed to the torque generated by the engine 2 and the torque generated by the motor 6.
In parallel with this, the travel mode (engine travel, motor travel, engine / motor travel) is selected based on the required torque, the travel state of the vehicle 1, the operating state of the engine 2 and the motor 6, or the SOC of the battery 18. . Then, a command is output to each of the engine ECU 24 and the inverter ECU 26 so as to achieve the distributed required torque in the selected travel mode, and the shift control of the transmission 8 is appropriately executed.

The engine ECU 24 operates the engine 2 by executing fuel supply amount control and supply timing control in order to achieve the travel mode and engine torque set by the vehicle ECU 22. In order to supply fuel to each cylinder, it is necessary to determine the crank position of the engine 2. Therefore, the engine ECU 24 is connected to a crank angle sensor 35 that outputs a pulse corresponding to the crank angle of the engine 2 and a cam angle sensor 37 that outputs a pulse corresponding to the cam angle. After determining the cylinder of the engine 2 based on the cam angle information, the fuel is supplied every time each cylinder reaches the crank angle corresponding to the target supply timing.
Further, the inverter ECU 26 drives and controls the inverter 20 to drive the motor 6 in order to achieve the travel mode and motor torque set by the vehicle ECU 22.

The battery ECU 28 detects the temperature of the battery 18, the voltage of the battery 18, the current flowing between the inverter 20 and the battery 18, and obtains the SOC of the battery 18 from these detection results, and detects the obtained SOC. It outputs to vehicle ECU22 with a result.
On the other hand, the vehicle ECU 22 automatically stops the engine 2 when a predetermined stop condition is satisfied by waiting for a signal or the like while the engine is running or the engine / motor is running, and then when the predetermined start condition is satisfied, the engine 2 Idle stop start control for automatically starting the engine is executed (idle stop start control means).
Since the engine stop condition and the start condition are disclosed in various documents, only an outline will be described. For example, the engine stop conditions are set such that the accelerator operation is stopped (Acc = 0), the vehicle speed V is reduced to 0, the shift lever is in the N range, and the brake is being operated. When all these conditions are satisfied, the vehicle ECU 22 considers that the engine stop condition is satisfied, outputs an engine stop command to the engine ECU 24, and the engine ECU 24 stops the fuel supply of the engine 2 based on the command. Stop automatically.

In addition, the brake operation stop is set as the engine start condition. When this condition is satisfied, the vehicle ECU 22 considers that the engine start condition is satisfied, connects the clutch 4, and outputs an engine start command to the engine ECU 24 and the inverter ECU 26. Based on the command, the inverter ECU 26 drives the motor 6 to crank the engine 2, and the engine ECU 24 starts the fuel supply of the engine 2 to automatically start the vehicle 1 so that the vehicle 1 can start.
The above engine stop condition and start condition are merely examples, and the present invention is not limited to this and can be arbitrarily changed.

Then, depending on the crank position when the engine is stopped, the engine startability at the subsequent automatic start, and hence the required start time and motor power consumption differ. For example, if the engine 2 is stopped at a crank position corresponding to immediately after the compression top dead center of any cylinder, cranking of the engine 2 can be smoothly started by motor torque at the time of automatic start, so that startability is improved. In addition, the start can be completed quickly with less motor power consumption. Therefore, such a crank position can be regarded as the optimum crank position.
This is an example of the optimum crank position, and the optimum crank position may be set based on other viewpoints. For example, if the engine 2 is stopped at a crank position corresponding to immediately before the compression top dead center of any cylinder, the engine 2 immediately reaches the first explosion with a slight cranking, so that the start can be completed more quickly. The crank position may be the optimum crank position.

  In this embodiment, in order to stop the engine 2 at the optimum crank position as described above, the clutch 4 is connected at the time of automatic stop and the motor 6 is regeneratively controlled so that negative torque (braking) is applied to the engine 2 during inertial rotation. However, it is necessary to use the crank angle information of the engine 2 as an index to determine the timing to apply the braking. However, as described above, the crank angle information is information handled on the engine ECU 24 side, and is not handled on the inverter ECU 26 side that controls the motor 6 because the crank angle information of the engine 2 is originally unnecessary, and this is used as an index. I can't.

In view of such a problem, the present inventor has found that the engine 2 at the time of automatic stop can be stopped at the optimum crank position by using an index based on the following knowledge.
First, the engine 2 is normally stopped by inertial rotation by stopping the fuel supply, which is one of the stop operations, but in the present invention, after the fuel supply is stopped, the engine 2 is regeneratively controlled by the motor 6 so as to reach a predetermined rotational speed. . On the other hand, the regenerative control of the motor 6 includes a rotational control that feeds back torque while maintaining the motor rotational speed Nm at a predetermined target value, and a feedback of the rotational speed while maintaining the motor torque at a predetermined target value. Can be roughly divided into torque control for regenerative power generation. Then, if the engine 2 is driven by the motor 6 and the rotation control is executed as the regenerative control, torque fluctuations corresponding to the strokes of the respective cylinders occur during that time. The regenerative state, for example, the regenerative rate fluctuates in synchronization with the torque fluctuation of the engine 2. Therefore, the regeneration state of the motor 6 such as the regeneration rate at this time can be used as an index instead of the crank angle information of the engine 2.

Based on the above knowledge, in the present embodiment, when the engine is automatically stopped when the engine stop condition is established, the inverter ECU 26 brakes the engine 2 with the regeneration rate of the motor 6 as an index and stops the engine 2 at the optimum crank position. Hereinafter, the control will be described in detail.
Here, in the present embodiment, since the motor 6 needs to be regeneratively controlled when the engine 2 is automatically stopped, the vehicle ECU 22 outputs an engine stop command to the engine ECU 24 when the engine stop condition is satisfied, while the inverter ECU 26 A command to start regenerative control is output. In addition, the vehicle ECU 22 connects the clutch 4 simultaneously with the establishment of the engine stop condition so that the torque of the motor 6 by the regenerative control is applied to the engine 2.
Further, as described below, the optimum crank position is determined starting from a specific peak of the fluctuation waveform of the motor regeneration rate. Therefore, a crank angle from a specific peak to the optimum crank position (hereinafter referred to as a stop crank angle Δθstop) is set by a test performed in advance.

FIG. 2 is a flowchart showing a motor braking control routine executed by the inverter ECU 26, and FIG. 3 is a time chart showing a braking state by the motor 6 when the engine 2 is automatically stopped.
The inverter ECU 26 executes the routine of FIG. 2 at a predetermined control interval. First, in step S2, the inverter ECU 26 determines whether or not a regenerative control start command is input from the vehicle ECU 22. When the determination in step S2 is No (negative), the routine is temporarily terminated, and when the determination is Yes (positive), the process proceeds to step S4. At this time, the clutch 4 is connected by the vehicle ECU 22 and the fuel supply of the engine 2 is stopped by the engine ECU 22 based on the engine stop command.
Although the clutch 4 is connected in this manner, the driving force of the engine 2 is not transmitted to the drive wheel 16 side via the clutch 4 because the transmission 8 is in the neutral state.

In step S4, the inverter ECU 26 starts rotation control with a predetermined motor rotation speed Nm as a target value as regeneration control of the motor 6 (rotation control execution means). As will be described below, the engine 2 is stopped by the braking of the motor 6, but a stop shock occurs when braking is suddenly applied in a high rotation range near the idle rotation. Therefore, in this embodiment, in order to suppress the stop shock, the target value of the rotation control is sequentially reset to the low rotation side, and the rotation of the engine 2 and the motor 6 is gradually reduced. However, the present invention is not limited to this, and the target value of the rotation control at this time may be constant.
As a result of gradually decreasing the rotation of the engine 2 and the motor 6, the regeneration rate of the motor 6 fluctuates in synchronism with the torque fluctuation generated according to the stroke of each cylinder of the engine 2. For example, if the engine torque increases, the motor regeneration rate also increases, and if the engine torque decreases, the motor regeneration rate also decreases.

The inverter ECU 26 monitors the fluctuation waveform of the regeneration rate of the motor 6 and identifies the peak of the regeneration rate in the subsequent step S6 (peak identifying means). In the present embodiment, the peak on the valley side (hereinafter referred to as the minimum peak) is specified when the regeneration rate decreases and reaches the minimum value first after the regeneration control of the motor 6 is started. The peak is specified because it can be reliably and accurately specified from the fluctuation waveform of the regeneration rate. However, the peak is not limited to the minimum peak, and the maximum peak that is the peak on the peak side of the fluctuation waveform may be specified. Moreover, it is not restricted to the peak of the first time, You may identify the peak after the 2nd time or the 3rd time.
On the other hand, as is apparent from FIG. 3, the optimum crank position is set in advance immediately after the compression top dead center after the passage of one cycle in the fluctuation period with respect to this minimum peak, and the crank from the minimum peak to the optimum crank position is preset. The angle is preset as a stop crank angle Δθstop. The position of the optimum crank position is particularly important with respect to the compression top dead center. In this case, if it is immediately after the compression top dead center, the optimum crank position is set immediately after the compression top dead center delayed by one cycle or two cycles. May be.

Thereafter, the inverter ECU 26 proceeds to step S8 to start a timer, and in subsequent step S10, converts the stop crank angle Δθstop to the stop time Δtstop based on the current motor rotation speed Nm (= engine rotation speed Ne) (time conversion) means).
That is, the peak of the fluctuation waveform of the regeneration rate occurs at every crank angle between the cylinders of the engine 2 (for example, 120 ° C. for 6 cylinders), and the timing at which the minimum peak is specified is when the clutch 4 is connected. It moves back and forth according to the phase between the engine 2 side and the motor 6 side. In addition, the first peak may not be specified for some reason. In this case, the second peak is specified as the minimum peak, and the peak specifying timing is delayed. Since the engine 2 and the motor 6 continue to decrease in rotation since the start of the regeneration control of the motor 6, the engine speed Ne when the minimum peak is specified is different.
Therefore, even if the stop crank angle Δθstop is the same, the time required to reach the optimum crank position (stop time Δtstop) is different. Therefore, the stop crank angle Δθstop is converted into the stop time Δtstop based on the motor rotation speed Nm when the minimum peak is specified as described above.

An example of a conversion procedure from the stop crank angle Δθstop to the stop time Δtstop will be described below.
First, the crank angle from the specified minimum peak to the optimum crank position is set in advance as the constant stop crank angle Δθstop as described above. On the other hand, the motor rotation speed Nm starts to decrease at the acceleration a simultaneously with the start of the regenerative control of the motor 6, and the acceleration a at this time can be regarded as a specific fixed value corresponding to the decrease in the target value of the rotation control.
Hereinafter, the motor rotation speed Nm is referred to as a motor speed, and the motor speed during idle operation of the engine when the regenerative control is started is ω, and the motor speed when the minimum peak is specified is ω1. The stop crank angle Δθstop can be expressed as follows.

As a result, the stop time Δtstop can be calculated from the stop crank angle Δθstop, the acceleration a, and the motor speed ω1 (motor rotation speed Nm) according to the above equation (1). Therefore, the inverter ECU 26 in this case executes the calculation process according to the equation (1) in step S10.
After calculating the stop time Δtstop as described above, the inverter ECU 26 proceeds to step S12 and determines whether or not the timer count value has reached the stop time Δtstop (optimum crank position determination means). If the determination in step S12 becomes Yes due to the elapse of the stop time Δtstop, it is considered that the engine 2 has reached the optimal crank position, and the motor torque is increased in step S14 (torque increase control means).

Specifically, if the target value is set to 0 while continuing the rotation control of the motor 6, the motor torque is controlled to the maximum value so that the motor rotation speed Nm is 0. Further, the regenerative control of the motor 6 may be switched to torque control, and a large torque that can stop the engine 2 may be set as a target value. In this case, the same effect can be obtained. Due to braking of the motor 6, the engine rotational speed Ne instantaneously decreases to 0, and the engine 2 stops near the optimum crank position. The period during which the motor torque is increased at this time may be set sufficiently longer than the required time predicted to be required for stopping the engine.
Since the braking of the motor 2 is strong, the time required to stop the engine is extremely short, and the delay of the actual engine stop position with respect to the optimum crank position is negligibly small. However, a large delay may occur. In such a case, cranking may not be started from the optimum crank position at the time of subsequent engine start. Therefore, a delay is obtained by previously subtracting the crank angle corresponding to the delay (= time from torque increase to engine stop) from the stop crank angle Δθstop and applying the subtracted stop crank angle Δθstop to the calculation of the stop time Δtstop. You may make it start the braking by the torque increase of the motor 6 at an early stage by an equivalent.

As described above, in the engine stop control device for a hybrid vehicle of this embodiment, when the engine 2 is automatically stopped, the motor 6 is driven by the rotating engine 2 by stopping the fuel supply, and the rotation control is executed as the regeneration control. doing. At this time, the crank angle of the engine 2 is determined using the regenerative ratio of the motor 6 that varies in synchronization with the torque variation of the engine 2 as an index, the motor torque is increased at the optimum crank position, the engine 2 is braked and stopped. I am letting.
Therefore, the crank angle of the engine 2 can be determined only on the inverter ECU 26 side without requiring a large specification change to input crank angle information having a large amount of information from the engine ECU 24 side to the inverter ECU 26 side. For this reason, it is possible to apply braking to the rotating engine 2 at an appropriate timing corresponding to the optimum crank position and stop the engine 2 near the optimum crank position. Therefore, it is possible to improve the engine startability during the subsequent automatic start, and to realize various effects such as an improvement in feeling due to a quick start completion or a reduction in motor power consumption.

  Further, in the present embodiment, the motor rotation at the time of peak identification is considered in consideration of the fact that the optimum crank position moves back and forth even if the stop crank angle Δθstop is the same according to the difference in the engine speed Ne at the time of specifying the minimum peak. The stop crank angle Δθstop is converted into a stop time Δtstop based on the speed Nm (motor speed ω1), and the optimum crank position is determined based on the converted stop time Δtstop. Therefore, the optimum crank position can always be accurately determined regardless of the engine speed Ne when the minimum peak is specified, and the engine 2 at the time of automatic stop can be more reliably stopped near the optimum crank position.

This is the end of the description of the embodiment, but the aspect of the present invention is not limited to this embodiment. For example, in the above-described embodiment, the invention is embodied as a truck engine stop control device. However, the vehicle type is not limited to this as long as it is a hybrid vehicle, and may be applied to a bus, a work vehicle, or a passenger car.
In the above embodiment, the regenerative control of the motor 6 is started immediately when the engine stop condition is satisfied, and the optimum crank position after the stop crank angle Δθstop is determined using the first minimum peak as a starting point. Absent. For example, if the engine 6 is braked by the motor 6 in a high rotation range as described above, a stop shock is generated. Therefore, from the viewpoint of suppressing the stop shock, the motor after the engine rotation speed Ne greatly decreases from the idle rotation. It is desirable to apply the braking by 6. Therefore, the optimum crank position may be set immediately after the compression top dead center in the rotation range sufficiently lower than the idle rotation, and the minimum peak may be specified on the lower rotation side according to the optimum crank position.
Therefore, in this case, it is not necessary to immediately start the regenerative control of the motor 6 when the engine stop condition is satisfied. Therefore, the regenerative control is started when the motor rotation speed Nm falls below a predetermined determination value, and the minimum peak is reached. Will be identified.

In the above embodiment, since the clutch 4 is interposed between the engine 2 and the motor 6, the regeneration control of the motor 6 is started after the clutch 4 is connected and operated when the engine 2 is automatically stopped. However, depending on the type of hybrid vehicle, the operation of connecting the clutch 4 is not an essential requirement.
For example, in a hybrid vehicle in which a motor is provided on the output shaft of an engine and the output shaft is connected to the drive wheel 16 side via a clutch, the engine and the motor are connected regardless of whether the clutch is connected or disconnected. Therefore, the same processing as that in the above embodiment is performed without requiring a clutch connection operation, and the present invention includes such a hybrid vehicle.

2 engine 6 motor 16 drive wheel 22 vehicle ECU (idle stop start control means)
26 inverter ECU (rotation control execution means, peak identification means,
(Optimum crank position discrimination means, torque increase means, time conversion means)

Claims (2)

The engine and the motor as the driving source of the vehicle are configured to transmit the driving force to the drive wheels via the transmission, and automatically stop by stopping the fuel supply of the engine when a predetermined stop condition is satisfied An idle stop start control means for automatically starting the engine when a predetermined start condition is established, and after stopping the fuel supply when the engine is automatically stopped by the idle stop start control means, In a hybrid vehicle control device capable of arbitrarily applying torque by regenerative control of the motor to the engine of
Rotation control execution means for executing rotation control for maintaining the rotation speed of the motor at a predetermined target value as the regeneration control when the engine is automatically stopped;
Peak specifying means for specifying a peak of the regenerative state of the motor that varies in synchronization with torque fluctuation of the engine by rotation control of the rotation control execution means;
Optimal crank position determining means for determining whether or not the engine has reached the optimal crank position after a preset stop crank angle has elapsed, starting from the peak of the regenerative state specified by the peak specifying means;
And a torque increase control means for increasing the torque of the motor and applying braking to the engine when it is determined by the optimal crank position determining means that the engine has reached the optimal crank position. Vehicle engine stop control device. Based on the rotational speed of the engine when the peak of the regenerative state of the motor is specified by the peak specifying means, comprising time conversion means for converting the stop crank angle into a stop time;
2. The optimal crank position determining means determines that the engine has reached an optimal crank position when the stop time converted by the time converting means has elapsed from the specified peak. The hybrid vehicle engine stop control device described.

Images