JP6891486B2 - Hybrid vehicle drive controller - Google Patents

Description

The present invention relates to a drive control device for a hybrid vehicle.

Patent Document 1 describes that there is a hybrid vehicle that uses the power of an engine and the power of a motor connected to the engine via a belt.

Japanese Unexamined Patent Publication No. 2004-251221

By the way, as described in Patent Document 1, in a vehicle equipped with a motor, when the vehicle is running and the engine is stopped, the driver's intention to start (including the intention to release the act of stopping the vehicle) When corresponding, the driving force of the motor may be used. In such a case, if the output performance of the motor is low, there is a problem that the driver's request cannot be promptly satisfied and a feeling of sluggishness is given.

Therefore, the present invention provides a drive control device for a hybrid vehicle that can suppress the feeling of sluggishness of the vehicle when the driver's intention to start is to be satisfied only by the driving force of the motor. I am aiming.

In order to solve the above problems, the present invention includes an internal combustion engine, a motor, and a control unit that controls the driving force of the internal combustion engine and the motor. The control unit decelerates the vehicle when the vehicle speed becomes lower than a predetermined value. During deceleration, idle stop is performed to stop the fuel injection of the internal combustion engine, and when a predetermined motor drive condition is satisfied in the idle stop state during deceleration, the motor is started to be driven, and then the motor is driven. A drive control device for a hybrid vehicle that performs EV traveling in which the vehicle is driven only by force, and the control unit starts driving the motor when the motor drive condition is satisfied from the idle stop state during deceleration. After that, the internal combustion engine is made to inject fuel until a predetermined time elapses, and after the predetermined time elapses, the EV traveling is performed while the accelerator is off.

As described above, according to the present invention, it is possible to suppress the feeling of sluggishness of the vehicle when trying to satisfy the demand from the driver only by the driving force of the motor.

FIG. 1 is a schematic block diagram of a drive control device for a hybrid vehicle according to a first embodiment of the present invention. FIG. 2 is a block diagram of a control system of a drive control device for a hybrid vehicle according to an embodiment of the present invention. FIG. 3 is a flowchart showing a procedure of EV traveling control processing of the drive control device of the hybrid vehicle according to the embodiment of the present invention. FIG. 4 is a time chart showing a change in torque due to EV travel control processing of the drive control device of the hybrid vehicle according to the embodiment of the present invention. FIG. 5 is a time chart showing changes in torque due to conventional EV travel control processing.

The drive control device for a hybrid vehicle according to an embodiment of the present invention is a drive control device for a hybrid vehicle including an internal combustion engine, a motor, and a control unit for controlling the internal combustion engine and the driving force of the motor. When the hybrid vehicle is driven by driving the motor from the state where the fuel injection of the internal combustion engine is stopped, the control unit causes the internal combustion engine to inject fuel until a predetermined time elapses after driving the motor. It is configured as.

As a result, it is possible to suppress the feeling of sluggishness of the vehicle when trying to satisfy the demand from the driver only by the driving force of the motor.

Hereinafter, the drive control device for the hybrid vehicle according to the embodiment of the present invention will be described in detail with reference to the drawings.

In FIG. 1, a vehicle 1 equipped with a drive control device for a hybrid vehicle according to an embodiment of the present invention includes an engine 2 as an internal combustion engine, a power supply system 3, and an ECU (Electronic Control Unit) 4 as a control unit. Is configured to include. Further, the vehicle 1 according to the present embodiment is a vehicle having an idle stop function as described later.

The engine 2 includes a piston, a cylinder, a connecting rod, etc. (not shown), and is a four-cycle engine that performs a series of four strokes including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke while the piston makes two reciprocations in the cylinder. It is composed of.

The piston housed in the cylinder is connected to the crankshaft via a connecting rod. The connecting rod is designed to convert the reciprocating motion of the piston into the rotational motion of the crankshaft.

A transmission 23 is connected to the engine 2. The transmission 23 shifts the rotation of the crankshaft of the engine 2 at a predetermined gear ratio and transmits it to the drive shaft 25 via a differential gear (not shown) or the like to rotate the left and right wheels 26. In FIG. 1, only the two wheels 26 are shown, and the remaining two wheels are not shown.

The power supply system 3 includes a main battery 31 as a first battery, a sub battery 32 as a second battery, a motor 33, and a switch (SW) circuit 34.

The main battery 31 is composed of, for example, a lead storage battery. The main battery 31 is electrically connected to the motor 33 via a switch circuit 34. The main battery 31 is provided with a battery status sensor 31a. The battery status sensor 31a detects the charge / discharge current, voltage, and battery temperature of the main battery 31. The battery status sensor 31a is connected to the ECU 4. The ECU 4 can detect the charging state of the main battery 31 by the output of the battery status sensor 31a.

The sub-battery 32 is composed of, for example, a lithium ion storage battery. The sub-battery 32 is electrically connected to the motor 33 via a switch circuit 34. The sub-battery 32 is provided with a battery status sensor 32a. The battery status sensor 32a detects the charge / discharge current, voltage, and battery temperature of the sub-battery 32. The battery status sensor 32a is connected to the ECU 4. The ECU 4 can detect the charging state of the sub-battery 32 by the output of the battery state sensor 32a.

The switch circuit 34 selects and connects at least one of the main battery 31 and the sub battery 32 as a power source for supplying electric power to the motor 33. The switch circuit 34 connects the motor 33 to the main battery 31 and the sub battery 32 under the control of the ECU 4.

The motor 33 is a motor having a function as an alternator that generates electricity by driving the engine 2 in addition to the function as a starter for starting the engine 2. The motor 33 is driven by electric power supplied from at least one of the main battery 31 and the sub battery 32. The motor 33 controls the output torque according to the torque command signal output by the ECU 4.

The motor 33 includes a motor pulley (not shown) connected to the rotor shaft of the motor 33. The pulley for the motor is connected to the crankshaft pulley of the engine 2 via a crankshaft pulley (not shown) and a belt 27 so as to be able to transmit power.

The ECU 4 is composed of a computer unit including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an input port, and an output port.

The ROM of the ECU 4 stores various control constants, various maps, and the like, as well as a program for causing the computer unit to function as the ECU 4. That is, when the CPU executes the program stored in the ROM, the computer unit functions as the ECU 4.

In addition to the above-mentioned battery status sensor 31a and battery status sensor 32a, various sensors such as an engine speed sensor 51, a vehicle speed sensor 52, an accelerator opening sensor 53, and a brake switch 54 are connected to the input port of the ECU 4. ..

The engine speed sensor 51 detects the engine speed of the engine 2. The vehicle speed sensor 52 detects the speed of the vehicle 1 from the rotation speed of the wheels 26 and the like.

The accelerator opening sensor 53 detects an accelerator opening, which is an opening of an accelerator pedal (not shown) operated by the driver, for example, when an acceleration is requested.

The brake switch 54 detects whether or not a brake pedal (not shown) is depressed. The brake switch 54 outputs an on signal when the brake pedal is depressed, and outputs an off signal when the brake pedal is not depressed.

On the other hand, various control objects such as the engine 2, the motor 33, and the switch circuit 34 are connected to the output port of the ECU 4.

The ECU 4 can execute idle stop control that automatically stops the engine 2 when a predetermined automatic stop condition is satisfied and restarts the engine 2 when a predetermined restart condition is satisfied. The predetermined automatic stop conditions include, for example, that the vehicle speed is smaller than the predetermined value, the brake is depressed, and the SOC (State Of Charge) of the main battery 31 and the sub battery 32 is larger than the predetermined value. .. Further, the predetermined restart conditions include, for example, that the accelerator operation has been performed, that the brake has not been stepped on, and the like.

Further, the ECU 4 restarts the engine 2 when the above-mentioned predetermined restart condition is satisfied. The ECU 4 supplies electric power from the main battery 31 to the motor 33 to increase the engine speed, causes the engine speed to reach a predetermined target speed, and restarts the engine 2. Here, the predetermined target rotation speed is, for example, the idle rotation speed of the engine 2. The ECU 4 determines that the restart of the engine 2 is completed when the engine speed reaches a predetermined target speed. The target rotation speed may be the engine speed when the engine 2 is completely detonated.

When the above-mentioned automatic stop condition is satisfied, the ECU 4 automatically stops the engine 2 in a state where the vehicle speed is lower than a predetermined value, and performs coast running. When the vehicle speed is equal to or higher than a predetermined value during coast traveling, the ECU 4 causes EV traveling in which the vehicle 1 is driven only by the motor 33 when a predetermined condition is satisfied.

Therefore, as shown in FIG. 2, the ECU 4 is based on the outputs of the battery status sensor 31a, the battery status sensor 32a, the engine rotation speed sensor 51, the vehicle speed sensor 52, the accelerator opening sensor 53, and the brake switch 54. It controls the engine 2 and the motor 33.

The ECU 4 drives the motor 33 when the motor drive condition is satisfied when the vehicle speed is equal to or higher than a predetermined value during coast traveling. The ECU 4 injects fuel into the engine 2 for a predetermined time after the motor driving conditions are satisfied and the motor 33 is started to be driven.

The motor drive conditions include, for example, that the engine speed is "0", that the brake is off, and the like.

The ECU 4 starts driving the motor 33 to inject fuel into the engine 2 for a predetermined time, and then causes EV travel when the EV condition is satisfied.

The EV condition includes, for example, that the SOC of the main battery 31 and the sub battery is larger than a predetermined value, the accelerator opening degree is "0", and the like.

The EV travel control process by the drive control device of the hybrid vehicle according to the present embodiment configured as described above will be described with reference to FIG. The EV travel control process described below is started when the ECU 4 starts the process, and is executed at preset time intervals.

In step S1, the ECU 4 determines whether or not the automatic stop condition is satisfied based on whether or not all of the following conditions 1) to 3) are satisfied. If it is determined that the automatic stop condition is not satisfied, the ECU 4 ends the process.
1) The vehicle speed is less than the specified value.
2) The brake is depressed.
3) The SOC of the main battery 31 and the sub battery 32 is larger than the predetermined value.

When it is determined that the automatic stop condition is satisfied, in step S2, the ECU 4 determines whether or not the motor drive condition is satisfied depending on whether or not all of the following conditions 4) and 5) are satisfied. If it is determined that the motor drive condition is not satisfied, the ECU 4 ends the process.
4) The engine speed is less than or equal to the idle speed.
5) The brake was turned from on to off.

When it is determined that the motor drive condition is satisfied, in step S3, the ECU 4 drives the motor 33 to increase the engine speed. In this case, the vehicle 1 is in a state in which the brake is turned off and the vehicle 1 must continue running due to the driver's change of mind (COM), and the ECU 4 drives the motor 33 to continue the running. ..

In step S4, the ECU 4 determines whether or not the engine speed exceeds a predetermined target speed. When it is determined that the engine speed does not exceed the target speed, the ECU 4 repeats the process of step S4 and waits for the engine speed to exceed the target speed.

When it is determined that the engine speed exceeds the target speed, the ECU 4 stops driving the motor 33 in step S5.

In step S6, the ECU 4 injects fuel into the engine 2 to generate engine torque.

In step S7, the ECU 4 determines whether or not a predetermined time has elapsed since the start of fuel injection into the engine 2. If it is determined that the predetermined time has not elapsed, the ECU 4 repeats the process of step S7 and waits for the predetermined time to elapse.

If it is determined that the predetermined time has elapsed, in step S8, the ECU 4 stops the fuel injection to the engine 2. In this way, since the engine 2 is driven for a predetermined time after the motor 33 is driven, the torque of the engine 2 is output, the lack of torque due to the motor 33 having a small output is compensated, and the feeling of pulling in the vehicle 1 is eliminated. be able to.

In step S9, the ECU 4 determines whether or not the EV condition is satisfied based on whether or not all of the following conditions 6) to 8) are satisfied.
6) The SOC of the main battery 31 is larger than the predetermined value.
7) The SOC of the sub-battery 32 is larger than the predetermined value.
8) The accelerator is off (the accelerator opening is "0").

When it is determined that the EV condition is satisfied, in step S10, the ECU 4 connects the sub-battery 32 to the motor 33, connects the main battery 31 to an electric load other than the motor 33, drives the motor 33, and runs the EV. And end the process. In this case, the vehicle 1 does not need to be accelerated because the accelerator is not depressed, and must continue running in this state, and the ECU 4 starts EV running and continues running.

When it is determined that the EV condition is not satisfied, in step S11, the ECU 4 does not drive the motor 33, but injects fuel into the engine 2 and drives the vehicle 1 by the engine 2. In this case, since the accelerator of the vehicle 1 is depressed and acceleration is required, the ECU 4 restarts the engine 2 and causes the vehicle to run normally.

The operation by such EV travel control processing will be described with reference to FIGS. 4 and 5. Note that FIGS. 4 and 5 show a case where the idling stop during deceleration shifts to EV running. FIG. 5 is a time chart showing changes in torque due to conventional EV travel control processing.

As shown in FIG. 5, at the timing t11, when the vehicle speed becomes lower than the predetermined value, the idle stop during deceleration is started, the engine 2 is automatically stopped, and the engine speed is lowered.

At the timing t12, when the brake is turned from on to off, the above-mentioned motor drive condition is determined, and when the motor drive condition is satisfied, the motor 33 is driven.

When the EV condition is satisfied at the timing t13, the sub-battery 32 is connected to the motor 33, the main battery 31 is connected to an electric load other than the motor 33, and the EV running is started. At this time, since the output of the motor 33 is small, the torque is insufficient and the vehicle 1 feels pulled in.

In this embodiment, as shown in FIG. 4, when the vehicle speed becomes lower than a predetermined value at the timing t1, the idle stop during deceleration is started, the engine 2 is automatically stopped, and the engine speed is lowered.

At the timing t2, when the brake is turned from on to off, the above-mentioned motor drive condition is determined, and when the motor drive condition is satisfied, the motor 33 is driven. After that, fuel is injected into the engine 2 for a predetermined time, and the torque of the engine 2 is output at the timing t3, so that the feeling of pulling in the vehicle 1 can be eliminated.

After that, when the EV condition is satisfied at the timing t4, the engine 2 is stopped, the sub-battery 32 is connected to the motor 33, the main battery 31 is connected to an electric load other than the motor 33, and the EV running is started.

As described above, in the above-described embodiment, when the vehicle speed is equal to or higher than a predetermined value during coast driving, the motor 33 is driven when the motor driving condition is satisfied, and then the ECU 4 injects fuel into the engine 2 for a predetermined time. To be equipped.
As a result, it is possible to suppress the feeling of sluggishness of the vehicle 1.

The ECU 4 starts driving the motor 33 to inject fuel into the engine 2 for a predetermined time, and then causes EV travel when the EV condition is satisfied.

As a result, it is possible to shift to EV traveling in which the vehicle 1 is driven only by the driving force of the motor 33 while suppressing the feeling of sluggishness of the vehicle 1.

Although the embodiments of the present invention have been disclosed, it is clear that some skilled in the art can make changes without departing from the scope of the present invention. All such modifications and equivalents are intended to be included in the following claims.

1 Vehicle 2 Engine (internal combustion engine)
4 ECU (control unit)
31 Main battery 31a Battery status sensor 32 Sub battery 32a Battery status sensor 33 Motor 34 Switch circuit 51 Engine speed sensor 52 Vehicle speed sensor 53 Accelerator opening sensor 54 Brake switch

Claims (1)

It includes an internal combustion engine, a motor, and a control unit that controls the driving force of the internal combustion engine and the motor.
When the vehicle speed becomes lower than a predetermined value, the control unit performs idle stop during deceleration to stop the fuel injection of the internal combustion engine during vehicle deceleration, and a predetermined motor drive condition is satisfied in the idle stop state during deceleration. This is a drive control device for a hybrid vehicle that performs EV traveling in which the vehicle is driven only by the driving force of the motor after the motor is started to be driven.
The control unit causes the internal combustion engine to inject fuel until a predetermined time elapses after the motor drive condition is satisfied from the idle stop state during deceleration and starts driving the motor, and the predetermined time A drive control device for a hybrid vehicle that causes the EV running to be performed while the accelerator is turned off after the lapse of time.

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