JP2002166754A - Control device of hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of a hybrid vehicle capable of certainly preventing occurrence of acceleration shock due to excessive torque by performing sufficient torque suppression during acceleration after deceleration. SOLUTION: This control device reduces fuel during the deceleration and keeps a throttle position in a full opening state, thereby sharing pumping loss of an engine to a regenerative torque of a motor/generator. In starting the acceleration, the throttle position is returned from the full opening state to an original state, the fuel reduction is returned, the motor/generator is delayed by a predetermined time T with respect to the timing, and the regeneration of the motor/generator is stopped. Reduction delay of intake air with respect to the change of the throttle position causes the generation of the excessive torque in starting the acceleration, but the excessive torque is absorbed by the regenerative torque of the motor/generator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control system for a parallel hybrid vehicle using an engine and a motor / generator as driving sources for traveling.

[0002]

2. Related Background Art As is well known, in a parallel type hybrid vehicle, a motor / generator is regeneratively controlled at the time of deceleration to recover running energy. At the time of deceleration, it is desirable to stop the engine after disconnecting it from the motor / generator and to distribute the motoring loss of the engine to the regenerative torque on the motor / generator side. In a hybrid vehicle of the type, there is not enough torque to start the engine in parallel with the subsequent acceleration, so that it is necessary to continue the operation of the engine even during deceleration.

Therefore, in such a one-motor type hybrid vehicle or the like, a fuel cut is executed instead of stopping the engine at the time of deceleration, and the throttle opening is controlled to be fully open to reduce motoring loss. I have.
FIG. 5 shows the motoring loss when the throttle is fully closed and when the throttle is fully opened. When the throttle is fully opened, the motoring loss is reduced by the pump loss when the throttle is fully opened, and the regenerative torque of the motor / generator can be increased. I understand.

[0004]

In the case where the throttle is fully opened during deceleration as described above, it is necessary to return the throttle opening to a value corresponding to the operating state simultaneously with the return of the fuel cut during the subsequent acceleration. However, even if the throttle opening is controlled to the closed side, the actual intake air does not immediately decrease due to the response delay due to the intake pipe volume, and as a result, excess torque is generated at the moment when the fuel cut is restored, It causes an acceleration shock.

Therefore, for example, in a hybrid vehicle equipped with an in-cylinder injection type engine, the mode is switched to the compression stroke injection mode at the beginning of acceleration to control the air-fuel ratio to a super lean air-fuel ratio near the stable combustion limit, thereby suppressing the engine torque. The aim is to prevent acceleration shock. However, the measures by the air-fuel ratio control do not sufficiently suppress the engine torque,
Accelerated shock could not be completely prevented. FIG. 6 shows the indicated average effective pressure Pi of the engine at the stable combustion limit. When the throttle opening is controlled from the fully opened state to the closed side with acceleration, the intake manifold pressure (the pressure in the intake manifold) becomes zero. This indicates that the indicated average effective pressure Pi is obtained from the vicinity (atmospheric pressure). now,
Assuming that the fuel cut is restored in a state where the intake manifold pressure is still 0 due to a response delay, the indicated average effective pressure Pi when the engine speed at that time is 800 rpm near idle.
Is 0.1MPa, which is 0.1M for friction loss
By canceling Pa, torque can be suppressed to around 0 MPa. However, at 2000 rpm, the indicated average effective pressure Pi becomes 0.2 MPa.
MPa, even if the friction loss is offset by 0.1
It turns out that excessive torque of MPa is generated, and the torque suppressing action is insufficient.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a control apparatus for a hybrid vehicle capable of sufficiently suppressing torque during acceleration after deceleration and reliably preventing the occurrence of acceleration shock due to excessive torque.

[0007]

In order to achieve the above object, according to the present invention, in a hybrid vehicle equipped with an engine and a motor / generator, an acceleration / deceleration state detecting means for detecting an acceleration / deceleration state of the vehicle; Fuel cut means for stopping the supply of fuel to the engine when the deceleration state is detected by the detection means, and regeneration control for regenerating energy by the motor / generator when the deceleration state is detected by the acceleration / deceleration state detection means. Means, a throttle control means for maintaining a throttle valve provided in the intake system of the engine at a predetermined opening or more when fuel supply is stopped by the fuel cut means, and an acceleration / deceleration state detection means for detecting an acceleration state. , The fuel cut means is stopped to start fuel supply, and the regenerative control means is delayed with respect to the start of fuel supply. And a regeneration stop delay means for stopping the regeneration.

Therefore, when the vehicle decelerates, the fuel supply to the engine is stopped, and regeneration is performed by the motor / generator. In order to increase the regenerative torque at this time, the throttle opening of the engine is equal to or more than a predetermined opening. Is maintained. Then, when acceleration is started thereafter, fuel supply is started and the throttle opening is returned to the original state. However, the stop of regeneration of the motor / generator is performed with a delay to these processes. Therefore, at the start of fuel supply, the torque is absorbed by the regeneration of the motor / generator,
Even if an excessive torque is generated due to a delay in decreasing the intake air with respect to a change in the throttle opening, the excessive torque is sufficiently suppressed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a control device for a hybrid vehicle embodying the present invention will be described below. As shown in the overall configuration diagram of FIG. 1, the hybrid vehicle of the present embodiment is configured as a parallel hybrid vehicle including an engine 1 and a motor / generator 2 as driving sources for traveling. A rotating shaft 2a of the motor / generator 2 is connected to an output shaft 1a of the engine 1 via a clutch 3, and a continuously variable transmission 4 is connected to the rotating shaft 2a of the motor / generator 2. The continuously variable transmission 4 has a clutch 5
The differential 6 is connected to drive wheels (rear wheels) 8 via left and right drive shafts 7.

The engine 1 is configured as an in-cylinder injection gasoline engine that injects fuel directly into a cylinder. In a cylinder injection type engine, since fuel injection can be performed not only in the intake stroke but also in the compression stroke, the optimum fuel injection mode (intake stroke injection mode or compression stroke injection mode) is executed in the operating state, and the compression stroke is performed. In the injection mode, an ignitable air-fuel mixture near the stoichiometric fuel is concentrated around the spark plug, and a lean air-fuel mixture is present around the igniter, enabling operation at an ultra-lean overall air-fuel ratio. . An actuator 9 is connected to a throttle valve (not shown) of the engine 1, and the actuator 9 drives the throttle valve to open and close.

On the other hand, a running battery 11 is connected to the motor / generator 2 via a controller 10. When the motor / generator 2 functions as a motor, such as when the motor is running, the controller 10 outputs a signal from the battery 11. Electric power is supplied to the motor / generator 2, while when the motor / generator 2 functions as a generator, such as during deceleration, the electric power obtained by regeneration is charged in the battery 11.

On the other hand, an ECU (electronic control unit) 21 having an input / output device, a storage device (ROM, RAM, etc.), a central processing unit (CPU), a timer counter and the like is installed in the vehicle interior. On the input side of the ECU 21,
A rotation speed sensor 2 for detecting the rotation speed Ne of the engine 1
2. An accelerator sensor 23 or the like as an acceleration / deceleration state detecting means for detecting a driver's accelerator operation amount APS is connected, and detection information from these sensors is input. E
The actuator 9 of the throttle valve, the controller 10 of the motor / generator 2, the clutches 3, 5, the continuously variable transmission 8, the unillustrated ignition plug and fuel injection valve of the engine 1, etc. are connected to the output side of the CU 21, EC
These devices are controlled by U21.

In the hybrid vehicle constructed as described above, the clutch 3 is disengaged and the clutch 5 is connected during normal running, so that the motor running with the motor / generator 2 as a drive source is prioritized. Is done. At this time, the ECU 21 sends the motor / generator 2 via the controller 10 based on the accelerator operation amount APS and the like.
To control the torque of the motor. When the motor torque is insufficient for the accelerator operation amount APS requested by the driver,
With the clutch 3 connected, traveling using both the engine 1 and the motor / generator 2 or traveling alone using the engine 1 is performed. At this time, the ECU 21 determines the target throttle opening in accordance with the map based on the accelerator operation amount APS, the engine load, and the like.
Controls the throttle opening of the engine 1 by
The fuel injection mode is switched according to the operation state as described above.

On the other hand, when the vehicle is started to decelerate during traveling using the engine 1 and the motor / generator 2 together,
The ECU 21 performs regenerative control of the motor / generator 2 (regeneration control means), executes fuel cut on the engine 1 side (fuel cut means), and controls the throttle opening to a fully open state, thereby reducing motoring loss of the engine 1. Is distributed to the regenerative torque on the motor / generator 2 side (throttle control means). FIG. 2 is a time chart showing the control situation at the time of deceleration. Hereinafter, the control situation at the time of deceleration will be described in detail with reference to FIG.

When the driver starts to decelerate the vehicle by operating the accelerator, the pulse width Pw of the fuel injection valve is gradually reduced based on the establishment of the fuel cut condition, and the fuel cut is started. After the throttle opening is once controlled to the closed side, the throttle opening is maintained in the fully open state. By controlling the throttle opening to the closed side, the engine torque is rapidly reduced to the negative side region, and thereafter, the pump loss is reduced by fully opening the throttle, and is maintained at a value closer to zero in the negative side region.

On the other hand, the regenerative control is started on the motor / generator 2 side, the motor torque becomes a negative value, and the total torque of the engine 1 and the motor / generator 2 becomes almost constant on the negative side, and the engine brake Is played. Then, the motoring loss of the engine 1 is reduced by the pump loss, the regenerative torque on the motor / generator 2 side is increased, and more traveling energy is supplied to the traveling battery 11.
Collected as charging current to

Thereafter, when the driver starts the acceleration by turning on the accelerator, the fuel cut is restored on the engine 1 side, and the throttle opening is changed from the full opening to the predetermined opening corresponding to the operating state. Will be returned. At this time, since the reduction of the intake air is delayed due to the intake pipe volume, an excessive torque is generated at the moment when the fuel cut is restored. Separately, the torque suppression routine of FIGS. 3 and 4 is executed. Hereinafter, the control situation at this time will be described in detail with reference to the drawings.

The routine shown in FIGS. 3 and 4 is executed when the deceleration of the vehicle is started. First, in step S2, it is determined whether or not the accelerator operation amount APS is 0, and in step S4, it is determined whether or not the fuel is being cut. Is determined. Step S2
And when the processing of step S4 is both YES (Yes),
That is, when the vehicle is decelerating and the fuel is being cut, the throttle opening is held at the fully open position in step S6 as described above in order to reduce the pumping loss, and the torque suppression routine ends.

On the other hand, when the determination in step S2 is NO (negative) due to the accelerator operation, or when the determination in step S4 is NO due to the return of the fuel cut, the process proceeds to step S8. In step S8, it is determined whether or not this processing is performed for the first time. When the process proceeds to step S8 for the first time after starting acceleration,
If the determination is YES, the leaning coefficient FcutK (n-1) at the time of return for setting the air-fuel ratio of the engine 1 to the lean side is set to a predetermined value in step S10, and the subtraction counter C is set to a predetermined value in step S12. After setting the value, the throttle opening control based on the normal map is executed in step S14. Therefore, the throttle opening is returned from the full opening to the predetermined opening according to the operating state as described above.

Here, the return leaning coefficient FcutK (n-1)
Is a coefficient for controlling the air-fuel ratio of the engine 1 to the lean side at the start of acceleration, and the subtraction counter C
This is a counter for delaying the regeneration stop timing of the generator 2 from the start of acceleration. Then the ECU
The process proceeds to step S16 to determine whether or not the following expression (1) is satisfied.

1.0-FcutK (n-1) <K0 (1) where K0 is a predetermined value. Next, step S18
Then, according to the following equation (2), the return leaning coefficient FcutK
(n) is calculated, and an air-fuel ratio coefficient A / FK is calculated in step S20 according to the following equation (3). FcutK (n) = 1.0 × (1-FG) + FcutK (n−1) × FG (2) A / FK = A / Fbase × FcutK (n) (3) where FG is 1 A / Fbase is a normal air-fuel ratio base value (a value calculated in the main routine based on the operating state of the engine 1). That is, the return leaning coefficient FcutK (n) is calculated by the above equation.
According to (2), the air-fuel ratio coefficient A / FK is gradually reduced according to the filter gain FG, and the corresponding air-fuel ratio coefficient A / FK is calculated by the above equation (3). In step S10, the return leaning coefficient FcutK (n-1) is set so that the air-fuel ratio coefficient A / FK corresponding to the vicinity of the lean stable combustion limit is calculated. After switching to the stroke injection mode, the actual air-fuel ratio is controlled near the stable combustion limit, and thereafter, gradually approaches the normal air-fuel ratio base value A / Fbase.

Then, the return leaning coefficient FcutK (n-1)
Gradually increases and approaches 1.0, and the step S16
If YES is determined in step S22, the process proceeds to step S22, where the return leaning coefficient FcutK (n) is set to 1.0. Therefore, thereafter, the normal air-fuel ratio base value A / Fbase is set as the air-fuel ratio coefficient A / FK. On the other hand, ECU2
In step S20, the process proceeds from step S20 to step S24, in which the subtraction counter C is decremented, and in step S26, the post-return M / G subtraction torque M / GTK is set to a predetermined value. In a succeeding step S28, it is determined whether or not the subtraction counter C has reached 0. If the answer is NO, the following equation (4) is obtained in a step S30.
After calculating the torque M / GT of the motor / generator 2 according to the above, the routine ends.

M / GT = M / GTbase−M / GTK (4) Here, M / GTbase is a normal motor torque (a value calculated based on the driving state of the vehicle). If the determination in step S28 is YES, the process shifts to step S32 to set the post-return M / G subtraction torque M / GTK to zero. Therefore, even after the start of acceleration, the motor torque M / GT is corrected to decrease until the subtraction counter C reaches 0.

When acceleration is started as described above, FIG.
As shown in (1), the return of the fuel cut and the control of the throttle opening from the full opening to the closing side are performed on the engine 1 side. In parallel with this, the air-fuel ratio of the engine 1 is reduced by the above-described torque suppression routine. , And the decrease correction of the motor torque M / GT is performed. FIG. 2 shows a case in which the M / G subtraction torque M / GTK after the return is set so that the motor torque M / GT substantially equal to the regenerative torque during deceleration is continued. 2 is continued for a predetermined time T even after the start of acceleration (regeneration stop delay means).

As a result, excessive torque (specifically, a sudden increase in the total torque of the engine 1 and the motor / generator 2) at the moment when the fuel cut is restored is suppressed. After that, the engine torque is gradually increased based on the setting of the air-fuel ratio coefficient A / FK in step S20, and then returned to the normal control state. On the other hand, the motor torque is reduced for a predetermined time corresponding to the subtraction counter C. After the elapse of T, the control is returned to the normal control state (in this case, torque 0).

As described above, according to the hybrid vehicle control apparatus of the present embodiment, during acceleration after deceleration, in addition to controlling the air-fuel ratio to near the stable combustion limit, the motor / motor control is performed in response to the return of the fuel cut. The regeneration of the generator 2 is delayed and stopped to thereby suppress the torque. If the air-fuel ratio is merely set near the stable combustion limit, as shown in FIG. 6, if the fuel cut is restored in the state where the intake manifold pressure is still near 0 (atmospheric pressure) due to a response delay due to the intake pipe volume, the engine When the rotational speed Ne is 2000 rpm, the indicated mean effective pressure Pi becomes 0.2 MPa, and as shown by a broken line a in FIG. 2, an excess torque equivalent to 0.1 MPa is generated even when the friction loss 0.11 MPa is offset. Resulting in.
Here, since the motor / generator 2 at the time of deceleration regeneration absorbs at least 0.1 MPa or more of torque, as a result, excessive torque is sufficiently suppressed as shown by the solid line b in FIG. Occurrence can be reliably prevented.

The description of the embodiment is finished above, but aspects of the present invention are not limited to this embodiment. For example, in the above-described embodiment, as shown in FIG. 1, the engine 1 and the motor / generator 2 are embodied in a hybrid vehicle in which the engine 1 and the motor / generator 2 are connected in series via the clutch 3, but the layout is not limited thereto. For example, the present invention may be embodied as a hybrid vehicle in which the motor / generator 2 is incorporated in the continuously variable transmission 4.

Further, in the above-described embodiment, as shown in FIG. 2, the motor torque M / GT substantially equal to the regenerative torque during deceleration is continued after acceleration, but as long as excess torque can be suppressed. , But not limited to this, step S
After the return at 24, the setting contents of the M / G subtraction torque M / GTK may be arbitrarily changed. Furthermore, in the above-described embodiment, the regeneration of the motor / generator 2 is delayed during acceleration after deceleration, and the air-fuel ratio is controlled near the stable combustion limit.
When excessive torque can be suppressed only by the regenerative torque of the motor / generator 2, torque suppression by air-fuel ratio control does not necessarily need to be performed.

On the other hand, in the above embodiment, the stop of the regenerative control means is delayed until the value of the subtraction counter C set to a predetermined value becomes zero. However, it is preferable that the subtraction counter C be adjusted to the engine speed Ne or the intake air amount. For example, the delay time may be set to be shorter in a low rotation range where the engine rotation speed Ne is low. In this case, in addition to the above effects, a delay time according to the excess torque amount can be set, so that poor acceleration at the time of returning from the fuel cut can be prevented.

[0030]

As described above, according to the control apparatus for a hybrid vehicle of the present invention, it is possible to sufficiently suppress torque during acceleration after deceleration, and to reliably prevent the occurrence of acceleration shock due to excessive torque. .

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing a control device for a hybrid vehicle according to an embodiment.

FIG. 2 is a time chart showing a control situation at the time of deceleration.

FIG. 3 is a flowchart illustrating a torque suppression routine executed by an ECU.

FIG. 4 is a flowchart illustrating a torque suppression routine executed by an ECU.

FIG. 5 is an explanatory diagram showing motoring loss when the throttle is fully closed and when the throttle is fully opened.

FIG. 6 shows the indicated average effective pressure P of the engine at the stable combustion limit.
It is explanatory drawing which shows i.

[Explanation of symbols]

Reference Signs List 1 engine 2 motor / generator 21 ECU (fuel cut means, regenerative control means, throttle control means, regenerative stop delay means) 23 accelerator sensor (acceleration / deceleration state detection means)

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) B60L 7/24 B60L 11/14 ZHV 11/14 ZHV F02D 29/02 ZHVD F02D 29/02 ZHV 41/12 310 41/12 310 330 J 330 B60K 9/00 E (72) Inventor Nobuaki Murakami 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation F-term (reference) 3D041 AA32 AA33 AB01 AD02 AD10 AE00 AE04 AE07 AF01 3G093 AA07 AA16 BA02 CB06 CB07 DA01 DA06 EA05 EA09 EB08 EC02 FA10 FA11 3G301 JA04 KA15 KA26 LA01 MA11 MA24 MA25 NC02 NE23 PE01Z PF03Z 5H115 PA01 PC06 PG04 PI16 PI22 PI29 PO02 PO07 PU22 PU23 PU25 QI04 QI09 QN03 QN12 RE05 TE05 RE05

Claims (1)

[Claims] 1. A hybrid vehicle comprising an engine and a motor / generator, wherein an acceleration / deceleration state detecting means for detecting an acceleration / deceleration state of the vehicle; Fuel cut-off means for stopping the supply of fuel to the engine, regeneration control means for regenerating energy by the motor / generator when the deceleration state is detected by the acceleration / deceleration state detection means, and fuel supply by the fuel cut-off means. When stopping, the throttle control means for maintaining a throttle valve provided in the intake system of the engine at a predetermined opening or more, and the fuel cut means is stopped when an acceleration state is detected by the acceleration / deceleration state detection means. To start the fuel supply, and stop the regeneration of the regenerative control means by delaying the start of the fuel supply. Control apparatus for a hybrid vehicle, characterized in that a regeneration stop delay means that.