JPH10331749A - Hybrid power train system for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce consumption of a power and to effect the smooth starting of an engine. SOLUTION: A first motor is arranged in a manner to be coupled to the crank shaft of an engine through a clutch starts an engine in a way that the number of revolutions lower than the number of idling revolutions forms the target number of revolutions. In this case, drive torque of the first motor is outputted to a maximum and the number of revolutions of an engine is gradually raised. When the number of revolutions of an engine reaches No, an injector is operated and fuel is injected in an engine. Torque is outputted and the engine increases the number of revolutions, and output torque of the first motor integrally coupled to the engine is decreased. When a decrease amount exceeds a given value ΔTm, it is decided that the engine effects complete explosion, starting drive of the first motor is stopped. This constitution shortens the starting time of an engine and saves power consumption, prevents the generation of sound vibration through continuous application of torque and provides excellent startability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid power train system for a vehicle.

[0002]

2. Description of the Related Art A typical power train in a vehicle driven by an internal combustion engine has, for example, a configuration as shown in FIG. That is, the automatic transmission 30 including the torque converter 3 and the transmission mechanism 5 is connected to the crankshaft 1 a of the engine 1, and the output torque of the engine 1 is transmitted to the drive wheels 7 via the reduction / differential unit 6. It has become so. Also, the torque converter 3 of the automatic transmission is used.
Is provided with a lock-up clutch 4. Further, auxiliary equipment 2 such as an air conditioner compressor, an alternator, a power steering pump, and an engine cooling water pump is connected to the crankshaft 1a of the engine.

In a vehicle equipped with such a power train, during operation, for example, when the vehicle is stopped at an intersection or the like, the engine 1 continues to drive the auxiliary device 2 and, in the traveling range, increases the creep force in preparation for the next start. Is occurring.
Therefore, a predetermined amount of fuel is consumed even though the vehicle is not traveling. Therefore, in order to reduce fuel consumption during operation, it is conceivable to stop the fuel for the engine 1 during deceleration or when the vehicle is stopped.

[0004]

However, the fuel consumption saving method described above has the following problems. The engine is started and operated not only when the vehicle is stopped but also during deceleration while the vehicle is running, so it is necessary to take measures such as automatically consuming the energy of the starting motor and starting automatically. It becomes. To solve this problem, for example, Japanese Patent Laid-Open No. 8-26
As disclosed in Japanese Patent No. 1118, while the motor torque for starting the engine is gradually increased, the torque is reduced to 0 on the way, and the change in the engine speed after a predetermined time is observed, thereby determining the complete explosion of the engine. Can be performed. When it is determined that the engine has completely exploded, the motor drive can be stopped and the engine can be started automatically.

However, in this method, the starting torque is gradually increased, and when a certain value is reached, the starting torque is set to zero. Since the complete explosion determination is performed by comparing with, the determination takes time. In particular, in the case of poor starting, the above-described determination that requires application of the driving torque and time is repeated, so that there is a problem that it takes a long time to finally determine the start of the engine. In addition, there is a problem that power consumption increases due to repeated operation of the motor, and noise and vibration occur.

Various hybrid systems have been proposed in which a motor is attached to an internal combustion engine so that the engine and the motor can be selectively used depending on the operating state. Even in such a hybrid system, when switching the drive from the motor to the engine, the engine must be started,
The problem of automatic starting of the engine and energy consumption during starting still remains.

In such a hybrid system, fuel consumption of the engine alone can be suppressed while the vehicle is driven by the motor, but since the motor is positioned substantially equivalent to the engine as a power source for traveling for a considerable distance, it is extremely large. Therefore, a heavy motor and a battery must be mounted, and there is a problem that the overall energy consumption efficiency is inferior to that of a system driven mainly by an engine. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a hybrid power train system for a vehicle that achieves remarkable savings in fuel consumption and that achieves better driving performance than before in view of the above problems. And

[0008]

SUMMARY OF THE INVENTION Accordingly, the present invention provides an engine wherein a crankshaft output of an engine is controlled by a transmission, a reduction unit,
When the first motor is attached to the crankshaft so as to be connectable to the crankshaft by a clutch and is provided with engine start control means, and the accelerator pedal is released. When the fuel supply to the engine is stopped and the engine is restarted, the engine start control means controls the rotation of the first motor at a rotation speed lower than the idling rotation speed, and transmits the clutch by transmitting the clutch. The driving torque of the first motor is transmitted to the crankshaft of the engine, and when the driving torque falls below a predetermined value, it is determined that the engine has completely exploded, and the driving of the first motor is stopped.

After the engine starting means determines that the engine has completely exploded, the engine start means controls the rotation of the first motor at an idling speed to continue driving the engine, and changes the engine speed to the idling speed. It is preferable to stop the driving of the first motor after the convergence.
The determination of the decrease in the drive torque of the first motor may be performed based on the drive torque calculated based on the current supplied to the first motor.

The first motor is always connected to an engine accessory, and the engine is motored by the first motor during vehicle deceleration to maintain the engine rotation state until the vehicle is stopped. While the engine is stopped, the clutch is disengaged, and the engine can be maintained at a rotational speed when the engine is restarted with the engine disconnected.

[0011]

The fuel consumption is reduced by stopping the fuel supply to the engine when the vehicle decelerates. At restart,
While the rotation of the first motor is controlled at a predetermined rotation speed,
The driving torque is transmitted to the crankshaft of the engine by transmitting the torque of the clutch. The driving starts the engine, but the output torque of the first motor is maximized. When the engine is started, the rotation speed increases by itself, and the output torque of the first motor decreases. Therefore, it can be determined whether or not the engine has completely exploded using the change in the output torque of the first motor. When it is determined that the engine has completely exploded, the driving of the first motor is stopped.
The driving torque generation time of the motor is minimized, and power consumption can be saved. In addition, since the engine is continuously started, a good startability can be obtained without generating noise and vibration.

After the engine has completely exploded, the rotation of the first motor is controlled at the idling speed, and if the engine continues to be driven, the speed of the engine converging to the idling speed becomes faster, and the starting speed of the engine is reduced. The effect that the rise is quick is obtained. When the decrease in the drive torque of the first motor is determined based on the drive torque calculated from the current supplied to the first motor, the complete explosion of the engine can be determined without using a torque sensor.

The first motor is always connected to an engine accessory, and the engine is motored by the first motor while the vehicle is decelerating, and the engine is kept rotating until the vehicle stops. Re-acceleration can be performed without restarting the engine at any time. Also, while the vehicle is stopped, by maintaining the rotation speed at the time of restarting the engine with the engine disconnected,
Even when the engine is stopped, functions such as auxiliary equipment are maintained, and the engine can be restarted without adding the start-up time of the first motor.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to examples. FIG. 1 is a skeleton diagram showing a power train in the embodiment. The engine 1 is connected on the one hand to an automatic transmission 30 comprising a torque converter 3, a lock-up clutch 4 and a transmission mechanism 5, a reduction / differential unit 6, drive shafts 7a and 7b, and drive wheels 7 in order. Is connected to auxiliary equipment 2 such as an air conditioner compressor, an alternator, a power steering pump, and an engine cooling water pump. Engine 1
Is supplied with fuel by a fuel injection valve (not shown). Further, a first motor 9 connected to the auxiliary machine 2 and connectable to the engine 1 is provided. The second motor 8 is connected in parallel.

More specifically, the output of the engine 1 is transmitted to the transmission mechanism 5 through the torque converter 3 connected to the crankshaft 1a or the lock-up clutch 4 connected in parallel with the torque converter 3, and further reduced and differentially driven. Drive wheels 7 from the device section 6 via drive shafts 7a and 7b
Is transmitted to The second motor 8 is connected to the third axle a of the transaxle of the deceleration / differential unit 6, and the output of the engine 1 and the output of the second motor 8 merge on the third axle.
To tell the power.

On the other hand, the engine 1 has a crank pulley 1b attached to its crankshaft 1a and a belt 9
a, the first motor 9 via the electromagnetic clutch 10
, And the first motor 9 and the auxiliary machine 2 are connected by a belt 2a. When the clutch 10 is engaged, the engine 1 and the first motor 9 rotate in association with each other at a constant rotation speed ratio.

Auxiliary equipment 2 such as an air conditioner compressor, an alternator, a power steering pump, an engine cooling water pump, etc., a second motor 8 and a first motor 9
Are supported by a block of the engine 1.

The automatic transmission 30 is provided with a hydraulic control unit 12. As shown in FIG. 2, the hydraulic control unit 12 includes an automatic transmission oil pump 20 driven by the engine 1 and a motor 2.
5 is connected to an oil pump 21 to generate a line pressure for operating the automatic transmission. Oil pump 2
The hydraulic pressures 0 and 21 are connected to the hydraulic control unit 12 via check valves 22 and 22, respectively, and the higher hydraulic pressure is output to the hydraulic control unit. Thus, even when the engine 1 is stopped, the internal clutch 5a such as a forward clutch that is engaged when the automatic transmission 30 is moved forward, for example, can be engaged, and power transmission is possible.

FIG. 3 shows a configuration of a control device in the power train. The control device includes an engine control unit 13, an automatic transmission control unit 14, and a hybrid system control unit 15, and operates by power supply from a low-voltage battery 29. The engine control unit 13 controls the engine 1 by controlling a throttle opening, an ignition timing, a fuel injection valve, an intake / exhaust valve, and the like, based on information from various sensors including an accelerator opening and an idle switch state.

The automatic transmission control unit 14 includes:
The automatic transmission 30 is controlled by controlling the lock-up clutch 4 and other gear ratio control actuators based on information from various sensors including a shift lever selection position, an engine speed, and a vehicle speed. The hybrid system control unit 15 controls the clutch 10 or the motor-driven automatic transmission oil pump 21 based on information from various sensors including an idle switch state, an engine speed, a vehicle speed, and a brake switch state. The second motor 8 and the first motor 9 are controlled via the inverter 26 and the inverter 27. The second motor 8 and the first motor 9 are connected to a high-voltage battery 28 via an inverter.
8 from the high voltage battery 2 during regenerative control.
8 is charged. Further, in order to share information for cooperative control in addition to information from various sensors, each control unit is connected by a communication line.

Next, the transition of the control state during the operation of the vehicle by the control device will be described. First, FIG. 4 is a time chart showing changes in each sensor signal and torque when decelerating from a state where the vehicle is traveling at a high speed at a constant speed. At the time of high-speed running, the fuel injection is performed and the engine 1 is in the fuel injection mode while the engine 1 is driven. However, the lock-up clutch 4 is engaged to prevent slippage in the torque converter 3 and reduce fuel consumption. Also, the first motor 9
Is not in the output state, but the clutch 10 is engaged, rotated by the output of the engine 1, and the auxiliary machine 2 is rotating. This corresponds to the section A in the figure.

Next, when the driver releases his / her foot from the accelerator pedal at time t1, and the idle switch state is turned on,
The engine control unit 13 determines that the vehicle has entered the deceleration state, and stops fuel injection to the engine 1. As a result, the engine 1 is reversely driven from the driving wheels 7, and the axle torque is on the driven side, so that an engine braking effect represented by the lock-up (L / U) axle torque occurs, and the lock-up (L / U) ) Move to deceleration mode.

Subsequently, when the driver depresses the brake pedal at time t2 and the brake switch state is ON, the hybrid system control unit 15 obtains the required deceleration from the map shown in FIG. The target axle torque to be performed is obtained, and the regenerative axle torque by the second motor 8 compensates for the lack of the lockup axle torque with respect to the target axle torque.

That is, the engine friction torque is determined from the engine friction map of FIG. 6, and the engine friction axle torque converted to the axle torque is calculated in consideration of the selected gear ratio. Also, the transmission friction axle torque converted to the axle is calculated from the transmission friction map of FIG. 7 in consideration of the engine speed and the gear ratio. The engine friction axle torque and the transmission friction axle torque become the lockup axle torque, and the regenerative axle torque is obtained by subtracting the lockup axle torque from the target axle torque.

During this time, the engine 1 continues to rotate,
Since the engine is rotated by the engine output, the auxiliary function remains. Further, since the oil pump 20 of the automatic transmission is also driven by the engine output, the internal clutch 5a of the automatic transmission 30 can also be engaged, and the power transmission function continues. Therefore, since the engine 1 is rotating during this deceleration, when re-acceleration, the time required for the cranking for the restart is not required, and the fuel injection can be executed immediately, and there is no fear of delay in rising of the driving force.

Next, if the vehicle speed decreases while the above-mentioned deceleration state continues, the engine speed Ne becomes equal to or lower than the idle speed as the vehicle speed decreases while the lock-up state continues. In this case, the gear ratio is increased, and the engine brake becomes strong, resulting in deterioration of drivability. Therefore, when the engine speed drops to a predetermined engine speed, the automatic transmission control unit 14 sets the lock-up signal to the non-engaged side to release the engagement of the lock-up clutch 4, and switches to a torque converter transmission in which slippage can be allowed.

However, even if the engagement of the lock-up clutch 4 is released, if the fuel injection of the engine 1 is stopped, the engine 1 rapidly reduces its rotation speed due to its own friction. Therefore, in the present embodiment, the hybrid system control unit 15
The engine 1 is motored by the first motor 9 in the engaged state so that the engine 1 is maintained at, for example, an idling speed so as not to stall. This lock-up clutch 4
Is in motoring deceleration mode after section C is released.

The power required for the motoring of the engine 1 only needs to share the shortage of the torque driven from the drive wheels 7 via the torque converter 3, so that the load on the first motor 9 is small. In the motoring deceleration mode, since the torque is switched to the torque converter axle torque lower than the lock-up axle torque in the section B, the regenerative axle torque of the second motor 8 is increased to obtain the target axle torque. During this time, the vehicle speed decreases as in the section B.

The determination of the regenerative axle torque is the same as that in the section B, but there is a difference in that the lockup is released. Here, the torque converter transmission axle torque is determined. From the gear ratio selected between the engine speed Ne and the vehicle speed V, the rotation speed ratio before and after the torque converter 3 can be known.
Then, the input capacity coefficient τ is obtained from the input capacity coefficient map of the torque converter as shown in FIG. 8, and the torque T ′ transmitted by the torque converter can be calculated by the following equation. T ′ = τ * Ne * Ne Then, the torque converter transmission axle torque converted to the axle torque is calculated in consideration of the gear ratio.

Assuming that the target axle torque is given by the sum of the torque transmission axle torque, the transmission friction axle torque and the regenerative axle torque, the regenerative axle torque is obtained by subtraction, and the second motor 8 is designed to realize this regenerative axle torque. Control. As described above, first, the first motor 9 is set so that the engine 1 is set to the target rotation such as the idling rotation speed.
By controlling the second motor 8 so as to realize the regenerative axle torque from the result, the engine rotation and the regenerative axle torque can be set as target values as a whole. By setting the engine 1 to the target rotation, the first motor 9 generates a vehicle creep torque when the vehicle stops.

FIG. 9 shows changes in the rotational speed and the torque when the vehicle is stopped from the deceleration state. The vehicle creep torque is generated by the first motor 9 until the vehicle stops, as described above.
Since there is no reverse driving force from the side, driving the engine 1 by overcoming engine friction with only the first motor 9 causes a large power loss of the first motor. Therefore, when the vehicle is stopped from the deceleration state, a transition mode of a section D in FIG. 9 is entered, the transmission capacity of the clutch 10 of the first motor 9 is reduced, and the engine speed is reduced by friction of the engine. However, during this time, the rotation of the first motor 9 is kept constant in order to maintain the function of the auxiliary machine 2. Then, instead, the second motor 8 is switched from regeneration to driving, and the second motor generates a creep force.

The driving torque of the torque converter 3 decreases as the engine speed decreases. The torque converter transmission axle torque can be calculated by τ * Ne * Ne * t as described above. When the torque converter transmission axle torque and the transmission friction axle torque are subtracted from the target axle torque, the target second motor 8 is obtained.
Drive axle torque is determined by In this way,
Eventually, when the engine speed becomes zero, the clutch 10 is disengaged, and the mode shifts to the idle stop mode in section E. Here, the first motor 9 only drives the accessory 2 and the second motor 8 maintains the creep force. When the engine 1 is stopped, the engine control unit 13 stores the stop position of the engine, that is, the cylinder, so that it can specify which cylinder will be the ignition timing or the fuel injection cylinder at the next start.

FIG. 10 shows changes in the rotational speed and the torque when the vehicle is started from the vehicle stopped state. When the accelerator is depressed and the vehicle starts and accelerates, the first motor 9 is used as a starter motor. At that time, if the engine 1 is started and then the acceleration is started, it takes time for cranking of the start and the rise of the torque is delayed, so that the starting torque is generated by the second motor 8 and the engine start is delayed. Supplement.

That is, when the accelerator pedal is depressed in the idle stop mode state in the E section and the accelerator opening reaches a predetermined value or more, the clutch 10 is engaged and the mode shifts to the start mode in the F section. The rotation speed of the first motor 9 is controlled so as to maintain the target rotation. However, when the clutch 10 is engaged and the rotation speed decreases, the maximum torque is output as a result. When the clutch is engaged, the first motor 9 is connected to the crankshaft 1a of the engine, and cranking is started. The fuel is supplied to the engine 1 from the fuel injection valve in accordance with the accelerator opening. At this time, based on the cylinder stop position stored when the engine is stopped, fuel injection is performed from an appropriate cylinder by sequential control in accordance with the ignition order.

When the rotation of the engine 1 rises due to cranking and the engine completely explodes and starts generating torque, the driving of the first motor 9 is stopped so that the engine 1 runs idle, and the auxiliary machine 2 is driven by the engine output. To do. Engine 1
Can be detected in the hybrid system control unit 15 because, for example, a sudden change in the engine speed or an inversion of the drive torque of the first motor 9 from positive to negative. .

On the other hand, during this time, a target axle torque corresponding to the accelerator opening is obtained from a map as shown in FIG. 11, a starting drive force is generated by the second motor 8, and the target axle torque is realized. The drive axle torque by the second motor 8 is obtained by subtracting the torque converter transmission axle torque and the transmission friction axle torque from the target axle torque. In this way, until the start of the engine 1 is completed, the second motor 8
, And a quick rise in drive torque is obtained. After the drive axle torque by the second motor 8 becomes 0, the fuel injection mode is set to the G section in which the target axle torque is covered only by the output of the engine.

In the idle stop mode in section E, the hydraulic pressure is supplied to the automatic transmission 30 by the motor-driven automatic transmission oil pump 21 even when the engine is stopped, so that the internal clutch 5a is engaged. The only delay is the cranking time of the start. Accordingly, the start assist time by the second motor 8 is shortened, and the vehicle speed range in which the start assist is performed can be reduced, so that the second motor 8 having a small output can be selected.

Next, the flow of the overall control in this embodiment will be described with reference to FIGS. First, step 10
At 1, 102, the transition end flag and the start mode flag are initialized, and the operation is started under the control of the fuel injection mode. In step 103, the engine control unit 13 checks the idle switch state. If the idle switch state is not on,
Proceeding to step 104, it is checked whether the start mode flag is set. Here, while the start mode flag is not set, the process returns to step 101, and the above flow is repeated.

When the idle switch state is turned on in the check at step 103, the routine proceeds to step 105, where the engine control unit 13 stops fuel injection. In the next step 106, the hybrid system control unit 15 checks the vehicle speed, and when the vehicle speed is not 0 and the vehicle is running,
At step 107, the automatic transmission control unit 14
Check if the lock-up signal at is on the fastening side. Here, when the lockup signal is on the engagement side, it is determined in step 108 that the lockup deceleration mode is set, and the process proceeds to the lockup deceleration mode control in step 120 and subsequent steps.

If the lock-up signal is on the non-engagement side, it is determined in step 109 that the vehicle is in the non-lock-up deceleration mode.
Is checked whether it is lower than the set value N1. Here, while the engine speed is high, the process returns to step 107, and the same flow is repeated. When the engine speed becomes lower than the first set value, steps 110 to 111 are executed.
Then, it is determined that the mode is the motoring deceleration mode, and the process proceeds to the motoring deceleration mode control after step 130.

On the other hand, if the vehicle speed becomes 0 in the check in step 106, the hybrid system control unit 15 checks the transition end flag in step 112. If the transition end flag is 0, it is determined in step 113 that the mode is the transition mode, and the process proceeds to transition mode control after step 140. When the transition end flag is set, the idle stop mode is determined in step 114, and the process proceeds to idle stop mode control in step 160 and subsequent steps. Further, when the start mode flag is set in the check in step 104, the process proceeds to start mode control after step 170.

In the lockup deceleration mode control, first, at step 120, the target axle torque is determined by the hybrid system control unit 15. Here, the target axle torque is read and determined according to the detected vehicle speed based on the vehicle speed using a map of the vehicle speed and the target axle torque as shown in FIG.

In the next step 121, the engine friction torque with respect to the engine speed is obtained from the engine friction map of FIG. 6, and the engine friction axle torque converted to the axle torque is calculated in consideration of the selected gear ratio. Then, in step 122,
A transmission friction axle torque converted to an axle is determined from the transmission friction map of FIG. 7 in consideration of the engine speed and the gear ratio.

Thereafter, in step 123, the regenerative axle torque is determined. Since the target axle torque is given by the sum of the engine friction axle torque, the transmission friction axle torque, and the regenerative axle torque, the regenerative axle torque is obtained by subtracting the engine friction axle torque and the transmission friction axle torque from the target axle torque. In this case, in addition to the idling switch state being ON, if the brake operation is further performed and the brake switch state is ON, the regenerative axle torque obtained as described above is further corrected by the vehicle speed. It is preferred to add In step 124, the regenerative axle torque is converted into a regenerative current to control the second motor 8,
Thereafter, the flow returns to step 103.

In the motoring deceleration mode control, first, at step 130, the hybrid system control unit 15 determines the target engine speed, and at step 131, the difference between the actual engine speed and the target engine speed is obtained. And step 13
In step 2, the difference is multiplied by a predetermined gain to obtain the torque operation amount of the first motor 9, and in step 133, the first motor is feedback-controlled. Thereby, the engine 1 is driven and held at the target engine speed, for example, the idling speed.

Subsequently, at step 134, the target axle torque is determined as in the previous step 120. Then, in step 135, the torque converter transmission axle torque is obtained, and in step 136, the transmission friction axle torque is obtained.

Thereafter, at step 137, a target regenerative axle torque is determined. Since the target axle torque is given by the sum of the torque converter transmission axle torque, the transmission friction axle torque, and the regenerative axle torque, the regenerative axle torque is obtained by subtracting the torque converter transmission axle torque and the transmission friction axle torque from the target axle torque. Step 1
In step 38, the regenerative axle torque is converted into a regenerative current of the second motor to control the second motor 8, and
Return to 03. This is repeated and the vehicle decelerates. When the vehicle speed becomes zero, the process proceeds to the transition mode control.

In the transition mode control, first, at step 140
In step (1), the hybrid system control unit 15 sets a target axle torque (creep torque), and in step 141, controls the transmission capacity of the clutch 10 by duty control to reduce the motoring of the engine by the first motor 9. During this time, the rotation speed of the first motor 9 is maintained at the level in the motoring deceleration mode in step 142.

In the next step 143, the transmission torque of the torque converter 3 is calculated. In step 144, the torque converter transmission axle torque (torque creep torque) transmitted from the engine 1 still rotating to the drive wheels 7 via the torque converter 3 ) Is calculated. And step 14
In step 5, the target creep torque by the second motor 8 is obtained by subtracting the torque converter creep torque from the target axle torque. In step 146, the second motor 8 is controlled by converting the target creep torque into a drive current.

In step 147, it is checked whether the idle switch state is on. Here, if the idle switch state is turned off, it means that the accelerator pedal has been depressed, so that the control shifts to the start mode control. If the idle switch state is ON, it is checked in the next step 148 whether or not the engine speed has become zero. Until the engine speed becomes zero, the routine returns to step 103 and repeats the above. When the engine speed reaches 0, the routine proceeds to step 149, in which the clutch 10 is completely disengaged, and the first motor 9 drives only the auxiliary machine 2 at a constant speed. Thereafter, a transition end flag is set in step 150, and the process returns to step 103.

In the idle stop mode control, in step 160, the first motor 9 is maintained at the target rotation speed by the hybrid system control unit 15, and in step 161 the target axle torque (creep torque) is maintained. The second motor 8 is controlled. In step 162, it is checked whether the idle switch state is on. Here, if the idle switch state is turned off, it means that the accelerator pedal has been depressed, so that the control shifts to the start mode control.

If the idle switch state is ON, it is checked in the next step 163 whether or not the vehicle speed is zero. If the vehicle is allowed to move forward without creeping even if the accelerator pedal is depressed, the process proceeds to the start mode control as described above. If the vehicle speed is 0 in the check in step 163, the process returns to step 160 and the above is repeated.
Continue the idle stop mode control.

In the start mode control, at step 170, the hybrid system control unit 15
First, the start mode flag is set. Then step 17
In step 1, the clutch 10 is engaged, and
In step 2, rotation speed control is performed so that the rotation speed of the first motor 9 is maintained. Thus, the cranking of the engine 1 is performed with the rotation output of the first motor 9. As a result of the control for maintaining the rotation speed, the output torque of the first motor 9 increases during cranking.

In step 173, the target axle torque is determined based on the map of FIG. 11, and in step 174, the target torque of the second motor 8 is determined from the difference between the target axle torque and the torque converter transmission axle torque. In step 175, the second motor 8 is controlled by converting the target torque into a drive current. During this time, in step 176, the engine control unit 13 performs engine start control such as fuel injection and ignition timing.

In step 177, it is checked whether or not the engine 1 has completely exploded.
Return to 2 and repeat the above. When Engine 1 completely explodes,
Proceeding to step 178, the driving of the first motor 9 is stopped and its output torque is set to zero. After the complete explosion, the drive of the second motor 8 ends when the torque converter transmission axle torque due to the engine output reaches the target axle torque. Thereafter, in step 179, the start mode flag is set to 0, and the process returns to step 103.

Next, the start determination of the engine 1 and the control of the first motor in steps 177 and 178 will be described. Here, an ammeter is provided in the power supply circuit of the first motor 9, and the detected value is output to the hybrid system control unit 15. The hybrid system control unit 15 creates a control command so that the first motor 9 can rotate at a constant speed, and calculates the drive torque of the first motor 9 based on the detection value of the ammeter. After the engine 1 is started, the driving torque of the first motor 9 is observed based on the detection value of the ammeter, and when the fluctuation reaches a predetermined value or more, it is determined that the engine 1 has completely exploded.
The control for the motor 9 is stopped. The fuel injection timing during the start of the engine is given to the engine control unit 13 by the hybrid system control unit 15.

Hereinafter, the flow of the engine start and the complete explosion determination will be described with reference to the flowchart of FIG. First, in step 200, a target rotation speed Nm of the first motor 9 is set. This target rotation speed Nm is set to be smaller than the idling rotation speed. In step 201,
A control command for controlling the first motor 9 to the target rotation speed Nm is created, and the control is performed at time t1. The engine 1 is started by driving the first motor 9, and the engine speed gradually increases as shown in FIG. During this time the first
The motor 9 generates a maximum driving torque.

The instantaneous rotation speed Ne of the engine is determined in step 2
In step 203, it is checked whether or not the number of revolutions has reached to perform fuel injection. If the engine speed Ne has not reached the engine speed No, the process returns to step 202 after elapse of the time set in step 204. If the engine speed Ne has reached the engine speed No in the check in step 203,
At step 205, at time t2, the drive current detection value Imo of the first motor immediately before the fuel injection is read, and then at step 206, the drive torque Tmo of the motor is estimated based on the drive current detection value Imo, and the estimation result is stored. I do.

In step 207, a fuel injection command is issued to the engine control unit 13, and fuel injection is started by the injector. In step 208, the motor drive current lm after fuel injection is taken into the engine, and in step 209, the drive torque Tm is estimated.

In step 110, the driving torque change (Tmo-Tm) before and after the fuel injection is calculated and a predetermined value ΔTm
Check for greater than. If the change in drive torque has not reached the predetermined value ΔTm, it is determined that the engine has not completely exploded, and the flow returns to step 208 after the elapse of the time set in step 211. During this time, the first motor 9
Start of the engine is continued. Then, when the change in the driving torque of the motor becomes equal to or more than the predetermined value in step 210, it is determined that the engine has completely exploded at time t3. In step 112, the control of the first motor 9 is stopped at time t4.

The present embodiment is constructed as described above. The first motor 9 which can drive the accessory 2 independently of the engine 1 and can be connected to the crankshaft 1a of the engine by the clutch 10, the torque converter 3 A second motor 8 connected between the driving wheels 7. The motor is regenerated by the second motor 8 during deceleration and the engine 1 is motored by the first motor 9 to prevent engine stall until the vehicle stops. Since the creep force is applied to the vehicle by the second motor 8 while driving the auxiliary equipment by the first motor 9, the fuel injection during stopping at a deceleration and at an intersection or the like can be stopped to obtain a remarkable fuel saving. .

Further, since the cranking is performed by the first motor 9 at the time of starting, the starter motor can also be used. Further, even when the vehicle is stopped, the auxiliary machine 2 is driven, and at the time of starting and starting, the second motor 8 is driven to assist the vehicle.

In particular, when the engine is started, the first motor 9 used as a starter motor is controlled to rotate at a constant speed, and a complete explosion of the engine is determined based on a change in the driving torque. Starting time can be minimized, and power consumption is saved. Further, since the drive torque is continuously applied during the start, the transition from deceleration to acceleration is smoothly performed without generating any sound vibration.

In the embodiment, the clutch for connecting the crankshaft of the engine and the first motor is attached to the first motor. However, the first motor is always connected to the auxiliary machine.
The position of the clutch is not particularly limited as long as it can be selectively connected to the crankshaft. For example, the clutch is attached to the auxiliary machine side, and the first motor and the crankshaft can be connected via the auxiliary machine. You can also.

Next, another engine start and complete explosion determination will be described as a second embodiment. In the first embodiment, the hybrid system control unit 15 controls the first motor 9 at a constant speed when the engine is started, and stops the drive control of the first motor 1 when the engine completely explodes.
The second embodiment is different from the first embodiment in that, even after the engine has completely exploded, the first motor is driven continuously by changing the target rotation speed of the motor to the idling rotation speed.

FIG. 20 is a flowchart showing the flow of starting the engine and determining the complete explosion. FIG. 21 is a time chart showing changes in engine speed, motor speed and motor torque. Step 200 to step 211
Up to this, the target rotation speed Nm of the first motor 9 is set as in the first embodiment. The engine speed while the engine 1 is started is read every moment. The driving torque before and after the fuel injection is calculated and estimated from the driving current, and the amount of change in the driving torque is calculated. If it is determined in step 210 that the amount of change is larger than the predetermined value ΔTm, the process proceeds to step 2120.

In step 2120, at time t4 when complete explosion is determined as shown in FIG. 21, the target rotation speed of the first motor 9 is set to Nm2 which is equal to or higher than the idling rotation speed N1 to perform motor control. In step 2121, the engine speed Ne of the engine 1 is read. In step 2122, it is checked whether the engine speed Ne is equal to or larger than the idling speed N1. If the engine speed Ne is lower, the process returns to step 2121. If the engine speed Ne is equal or higher, the motor control is stopped at time t5 in step 2123. As described above, even after the complete explosion of the engine, the driving by the first motor 9 is continued, and the transition of the rotation of the engine to the idling rotation speed is assisted, so that the effect of further improving the startability is obtained.

[0068]

As described above, according to the present invention, the first motor, which can be connected to the crankshaft of the engine by a clutch, is provided, the engine speed control means is provided, and the fuel supply is stopped during vehicle deceleration. When starting the engine, the first motor is controlled at a constant speed to start the engine. Therefore, the complete explosion of the engine can be quickly determined, so that the time required for the start is shortened, the power consumption is reduced, and at the time of restart, It has the effect of obtaining good startability.

After the engine has completely exploded, the rotation of the first motor is controlled at the idling speed, and if the engine continues to be driven, the speed of the engine converging to the idling speed becomes earlier, and the starting speed of the engine is reduced. The effect that the rise is quick is obtained.

The first motor is always connected to an engine accessory, and the engine is motorized by the first motor during vehicle deceleration, and the engine rotation state is maintained until the vehicle stops. Re-acceleration can be performed without restarting the engine at any time. Also, while the vehicle is stopped, by maintaining the rotation speed at the time of restarting the engine with the engine disconnected,
Even when the engine is stopped, the functions of the auxiliary equipment and the like are maintained, and an effect that the engine can be restarted without adding the start-up time of the first motor is obtained.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram showing a power train according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a hydraulic supply source for an automatic transmission.

FIG. 3 is a diagram illustrating a configuration of a control device in a power train.

FIG. 4 is a time chart in the case of decelerating from a state of traveling at a constant speed.

FIG. 5 is a diagram showing a map for obtaining a target axle torque during deceleration.

FIG. 6 is a diagram showing an engine friction map.

FIG. 7 is a diagram showing a transmission friction map.

FIG. 8 is a diagram showing an input capacity coefficient map of the torque converter.

FIG. 9 is a time chart when the vehicle stops from a deceleration state.

FIG. 10 is a time chart when the vehicle starts from a vehicle stop state.

FIG. 11 is a diagram showing a map for obtaining a target axle torque at the time of starting.

FIG. 12 is a flowchart illustrating a flow of overall control in the embodiment.

FIG. 13 is a flowchart illustrating a flow of overall control in the embodiment.

FIG. 14 is a flowchart illustrating a flow of overall control in the embodiment.

FIG. 15 is a flowchart illustrating a flow of overall control in the embodiment.

FIG. 16 is a flowchart illustrating a flow of overall control in the embodiment.

FIG. 17 is a flowchart illustrating a flow of overall control in the embodiment.

FIG. 18 is a flowchart showing a flow of engine start control.

FIG. 19 is a time chart showing changes in engine speed, motor speed, and motor torque.

FIG. 20 is a flowchart showing a flow of another engine start control.

FIG. 21 is another time chart showing changes in engine speed, motor speed, and motor torque.

FIG. 22 is a diagram showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 1a Crankshaft 2 Auxiliary equipment 3 Torque converter 4 Lock-up clutch 5 Transaxle transmission unit 5a Internal clutch such as forward clutch 6 Reduction / differential unit 7 Driving wheels 7a, 7b Drive shaft 8 Second motor 9 First Motor 10 Clutch 12 Hydraulic control unit 20 Oil pump for automatic transmission 21 Oil pump 22 Check valve 25 Motor 6a Transaxle third shaft

Claims (5)

[Claims] An engine transmits its crankshaft output to a drive wheel via a transmission, a deceleration unit, and an axle to serve as a power source for vehicle traveling, and a first motor is provided so as to be connectable to the crankshaft by a clutch. And engine start control means for stopping fuel supply to the engine when the accelerator pedal is released and restarting the engine, wherein the engine start control means controls the first motor. A rotation control is performed at a predetermined rotation speed, a drive torque is transmitted to a crankshaft of the engine by engaging the clutch, and it is determined that the engine has completely exploded due to a decrease in the drive torque, and a rotation control of the first motor is performed. A hybrid power train system for a vehicle, wherein the vehicle is stopped. 2. The hybrid power train system for a vehicle according to claim 1, wherein the first motor is controlled at a rotation speed lower than an idling rotation speed of the engine. 3. The engine starting means, after determining that the engine has completely exploded, maintains the drive to the engine, converges the rotation of the engine to an idling speed, and then controls the rotation of the first motor. The hybrid power train system for a vehicle according to claim 1 or 2, wherein the vehicle is stopped. 4. The vehicle start control device according to claim 1, wherein the determination of the decrease in the drive torque of the first motor is performed based on a drive torque calculated based on a current supplied to the first motor. 5. The motor according to claim 1, wherein the first motor is constantly connected to an engine accessory, the engine is motorized by the first motor during vehicle deceleration, and an engine rotation state is maintained until the vehicle stops. 2. The vehicle according to claim 1, wherein the clutch is disengaged while the vehicle is stopped, and is configured to maintain a rotation speed when the engine is restarted with the engine disconnected. 3. Hybrid powertrain system.