JP2021154996A - Control device of vehicle - Google Patents

Abstract

To shorten a necessary time of an engine automatic stop, and to improve fuel economy.SOLUTION: In a vehicle 1 having a clutch 32 for connecting an output shaft of an engine 2 and a transmission 3, and releasing the connection, an electric generator 23 having a function for generating power by the rotation of the output shaft, and a function for restarting the engine, a main battery 24 charged by the power of the electric generator, and capable of supplying power to the electric generator, a general load 6 and a load 7 to be protected, and an auxiliary battery 25 charged by the power of the electric generator, and capable of supplying power to the load to be protected, the vehicle performs control (130) for simultaneously performing automatic stop preparation control (120) for releasing a clutch by gradually decreasing engine torque according to the establishment of an engine automatic stop condition (100), and power supply changeover control (110) including the connection of the auxiliary battery and the load to be protected, and the disconnection of the auxiliary battery and the electric generator in parallel with each other, and stopping the engine after a finish of the control.SELECTED DRAWING: Figure 4

Description

The present invention relates to a vehicle control device such as a hybrid system or an idling stop system that automatically stops and automatically restarts an engine during traveling.

The hybrid system, mild hybrid system, and idling stop system are based on an internal combustion engine vehicle, but have various advantages such as control that automatically stops and restarts the engine while driving and regenerative braking, which greatly improve fuel efficiency. It has been put to practical use in the form.

For example, in Patent Document 1, a power supply circuit such as a motor generator or a starter that automatically restarts an engine is shared with an auxiliary electric device, and a device that cannot tolerate a voltage drop due to the operation of the motor generator or the starter (protected). Only the load) is disclosed as a system that switches to another power supply (auxiliary power supply) at the time of restart.

By adopting such a system, it is possible to configure a mild hybrid system or an idling stop system only with a low-voltage power supply circuit, and as disclosed in Patent Document 1, a high-voltage system for a drive motor generator. A hybrid system can be configured without using a DC-DC converter by arranging power supply circuits in parallel.

JP-A-2017-105377

In the above system, if switching to the auxiliary power supply is performed when the engine is restarted, the restart start and the rise of the driving force are delayed by the time required for the switching operation, and the operability is impaired. Therefore, before the engine is automatically stopped, the switching control to the auxiliary power supply is performed when the precondition for automatic stop is satisfied, and the control for automatically stopping the engine is started after the control is completed.

When the engine was automatically stopped, the engine torque was gradually reduced to zero and then the clutch was released (automatic stop preparation control) to stop the fuel injection. Therefore, it takes time from the establishment of the precondition for automatic stop to the actual stop of fuel injection, and the engine continues to operate during that time, so there is room for further improvement in fuel efficiency.

The present invention has been made in view of the above circumstances, and an object of the present invention is to shorten the time required for automatic engine stop and further improve fuel efficiency in a vehicle equipped with a hybrid system or an idling stop system. To do.

In order to solve the above problems, the present invention
With an internal combustion engine
A clutch for connecting / releasing the output shaft of the engine and the transmission, and
A motor generator having a function of generating electricity by rotating the output shaft and a function of restarting the engine,
It is connected to the electric generator and a general load, can be connected to a protected load, is charged with the electric power generated by the electric generator, and can supply power to the electric generator, the general load, and the protected load. Main battery and
An auxiliary battery that can be connected to the motor generator and the protected load, is charged with the electric power generated by the motor generator, and can supply power to the protected load.
It is a vehicle control device equipped with
Automatic stop preparation control that gradually reduces the torque of the engine to release the clutch according to the satisfaction of the automatic stop condition of the engine, connection between the auxiliary battery and the protected load, and the auxiliary battery and the motor generator. It is configured to perform power switching control including disconnection from the machine at the same time, and to stop the engine after the completion of the control.
It is in the control device of the vehicle.

According to the control device according to the present invention, automatic stop preparation control for gradually reducing the engine torque to release the clutch and power switching control for switching the power supply of the protected load to the auxiliary battery according to the establishment of the automatic engine stop condition. Since the above steps are performed in parallel, the time required for automatic engine stop is shortened, and fuel consumption can be expected to be reduced accordingly.

It is a system block diagram of the vehicle in which this invention is carried out. It is an auxiliary power supply circuit diagram at the time of engine operation. It is an auxiliary power supply circuit diagram at the time of engine stop / restart. It is a flowchart which shows the control which concerns on embodiment of this invention. It is a time chart which shows the control when it stops automatically from a power running state. It is a time chart which shows the control when the switching to the auxiliary power supply is not completed at the time of automatic stop from the power running state. It is a time chart which shows the control when it stops automatically from a stopped state. It is a flowchart which shows the outline of the control of this invention (a) and comparative example (b).

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In FIG. 1, the vehicle 1 is configured as a parallel hybrid vehicle in which an engine 2 and a drive motor 4 can transmit power to a drive wheel 5 via a transmission 3, and controls the hybrid system as a control device. It includes an HCU (Hybrid Control Unit) 10, an ECU (Engine Control Unit) 20 that controls the engine 2 and auxiliary machinery, and a TCU (Transmission Control Unit) 30 that controls the transmission 3.

The engine 2 is, for example, a reciprocating internal combustion engine, and the ECU 20 performs engine control based on an input signal from a sensor that detects each state value reflecting the operating state of the engine 2.

For example, the ECU 20 detects the piston position and the engine rotation speed based on the input signals from the crank angle sensor and the cam angle sensor, and has an intake air amount sensor, an intake temperature sensor, a water temperature sensor, an air-fuel ratio sensor, and an accelerator opening sensor ( The fuel injection amount, fuel injection timing, ignition timing, and valve opening / closing timing are determined based on the detected values such as load requirement), and the control signal is output to the fuel injector, ignition plug, etc. to optimize the operating condition of the engine. To become.

A starter 22 for cold starting is attached to the output side end (flywheel) of the crankshaft 21 forming the output shaft of the engine 2, and the other end (pulley) of the crankshaft 21 is provided with a belt. An ISG23 capable of transmitting torque is attached.

The ISG (Integrated Starter Generator) 23 is a generator with a starter function (electric generator, motor generator), is connected to the main battery 24 via the main power supply circuit 26, and rotates the engine 2 (crank shaft 21). It has a generator function of charging the main battery 24 (and the auxiliary battery 25) with the electric power generated by the main battery 24 and a starter function of restarting the engine 2 with the electric power supplied from the main battery 24.

The output side end (flywheel) of the crankshaft 21 is connected to the input shaft 31 of the transmission 3 via the clutch 32 so as to be able to transmit torque, and by releasing the clutch 32, the engine 2 and the transmission 3 are released. And are blocked.

The transmission 3 is an automatic transmission (AT) provided with a mechanism such as a gear or a belt that changes the gear ratio between the input shaft 31 and the output shaft 34, and has various types such as AMT, CVT, and planetary gear type. It is configured as an AMT (Automated Manual Transmission) equipped with a type, for example, a constantly meshing type transmission mechanism consisting of a parallel shaft gear mechanism, a shift actuator (not shown), and a clutch actuator, and the shift actuator and the clutch actuator are controlled by the TCU 30 to shift gears. It switches stages and disconnects from the engine 2.

One end of the output shaft 34 of the transmission 3 is connected to the drive shaft 33 via a differential gear, torque can be transmitted to the drive wheels 5, and the other end of the output shaft 34 is via a speed reducer (not shown). The drive motor 4 is connected so that torque can be transmitted.

The drive motor 4 (MGU; Motor Generator Unit) is connected to the inverter 41 and the drive battery 42 via the high voltage power supply circuit 43, and is supplied from the drive battery 42 by the drive command of the HCU 10 (high voltage power supply (MGU). For example, while being driven by 100V), it also has a function as a generator that regenerates power by rotating the drive shaft 33 (output shaft 34) according to the regeneration command of the HCU 10 and charges the drive battery 42.

The HCU 10, ECU 20, and TCU 30 include a CPU that performs arithmetic processing, a ROM that stores control programs and setting data, a RAM that reads control programs and setting data, and stores dynamic data and arithmetic processing results, and a communication I / F. It is composed of a microcomputer (MCU) equipped with the above, a power supply circuit, an input / output circuit, a protection circuit, and the like, and the HCU 10 controls the hybrid system by cooperative control with the ECU 20 and the TCU 30.

With the above configuration, the vehicle 1 travels only by the engine torque generated by the engine 2, travels only by the motor torque generated by the drive motor 4 (EV travel), and drives the drive motor to drive the engine. Traveling that assists the engine torque of 2 (assisted traveling) is possible.

Further, the ECU 20 monitors the vehicle information input through the in-vehicle network, outputs a signal for automatically stopping the engine 2 when a predetermined stop condition is satisfied, and outputs an ISG 23 when the predetermined restart condition is satisfied. It is possible to execute control (idling stop control) for outputting a signal to (or the starter 22) for automatically restarting the engine 2.

By the way, as already described, in the case of automatic engine stop / restart, when the automatic stop precondition is satisfied before the engine is automatically stopped, the voltage drop during driving of the ISG23 (or starter 22) cannot be tolerated. Control is performed to switch the power supply of the protective load 7 from the main power supply (main battery 24) to the auxiliary power supply (auxiliary battery 25).

As shown in FIG. 1, the low voltage (for example, 12V) auxiliary power supply circuit is composed of a main power supply circuit 26 and an auxiliary power supply circuit 27. Low-voltage devices such as a starter 22 and a general load 6 are connected to the main power supply circuit 26, and power can be supplied to these devices from the main battery 24. As the main battery 24, for example, a lead battery can be used. The general load 6 includes, among auxiliary machines, equipment that can tolerate a voltage drop during driving such as ISG23 and equipment that does not affect the running performance of the vehicle 1, such as a blower and a defogger of an air conditioner.

The auxiliary power supply circuit 27 can be connected to the main power supply circuit 26 via the first switch SW1, the protected load 7 is connected to the auxiliary power supply circuit 27, and the auxiliary battery 25 is connected via the second switch SW2. Can be connected to. As the auxiliary battery 25, for example, a lithium ion battery (LiB) can be used.

With the above configuration, as shown in FIG. 2, when the first switch SW1 and the second switch SW2 are closed, the auxiliary battery 25 can be charged by the power generated by the ISG 23, and the protected load 7 is powered. Can be supplied. When the auxiliary battery 25 is fully charged (charge rate SOC is equal to or higher than a predetermined value), the second switch SW2 is opened to prevent overcharging.

Further, as shown in FIG. 3, even when the first switch SW1 is open, if the second switch SW2 is in the closed state, power can be supplied from the auxiliary battery 25 to the protected load 7. The protected load 7 includes auxiliary equipment such as a starter 22 and an ISG23 that cannot tolerate a voltage drop during driving and equipment that affects the running performance of the vehicle 1, such as EPS (electric power steering) and ESP. (Registered trademark; electronic stability program, vehicle behavior stabilization control system), navigation system, or lights such as headlights and taillights.

Next, FIG. 4 is a flowchart showing the engine automatic stop control (idling stop control) according to the present invention, and the engine automatic stop control will be described below.

The ECU 20 monitors vehicle information input through the vehicle-mounted network (step 100), and reduces the driver-required torque when a predetermined stop condition is satisfied (for example, when the clutch 32 is connected and powering is performed). When automatic stop is possible due to such factors), the switching control 110 to the auxiliary power supply and the automatic stop preparation control 120 are executed in parallel at the same time.

In other words, the automatic stop preparation control 120 is immediately executed without waiting for the completion of the switching control 110 to the auxiliary power supply.

That is, in the automatic stop preparation control 120, the ECU 20 acquires the connected / released state of the clutch 32 from the TCU 30 (step 121), and when the clutch 32 is in the connected state, the engine torque is gradually reduced to 0 (step 122). , Issue a clutch 32 release command to the TCU 30 (step 123). When the clutch 32 is released, the automatic stop preparation control 120 is completed.

On the other hand, in the switching control 110 to the auxiliary power supply, first, the ECU 20 stops the ISG power generation (step 111), and when the voltage of the main power supply circuit 26 becomes equal to or less than the specified value (step 112), the BMU of the auxiliary battery 25 A connection instruction for the second switch SW2 is issued to (power management unit) (step 113).

Next, when the ECU 20 refers to the BMU and detects the completion of the connection of the second switch SW2 (the connection between the main power supply circuit 26 and the auxiliary power supply circuit 27) (step 114), the ECU 20 instructs the BMU to open the first switch SW1. (Step 115).

After that, in step 116, the ECU 20 refers to the BMU, and when the opening of the first switch SW1 is completed, the main power supply circuit 26 and the auxiliary power supply circuit 27 are cut off, and the switching of the power supply of the protected load 7 to the auxiliary battery 25 is completed. Only when it is detected that the engine 2 has been completely stopped (the fuel injection is stopped even in the vicinity of the idle speed) is permitted (step 130).

On the other hand, if the opening of the first switch SW1 is not completed in step 116, the idle operation is continued until the opening of the first switch SW1 is completed (step 117). That is, when the engine speed is sufficiently higher than the idle speed, the fuel injection is stopped, and when the engine speed is near the idle speed or less, the fuel injection control is continued.

FIG. 8A is a simplification of the flowchart of FIG. 4, and shows the engine automatic stop control according to the above embodiment, which executes the automatic stop preparation control 120 in parallel with the switching control 110 to the auxiliary power supply. 8 (b) shows an engine automatic stop control of a comparative example in which the automatic stop preparation control 220 is executed after the switching control 210 to the auxiliary power supply is completed.

In this way, by immediately executing the automatic stop preparation control 120 without waiting for the completion of the switching control 110 to the auxiliary power supply, the start of the automatic stop preparation control 120 is accelerated and the time required for automatic engine stop is shortened. Therefore, fuel consumption can be expected to be reduced accordingly.

FIG. 5 is a time chart when the automatic engine stop control is started from the power running state, the solid line corresponds to the control according to the embodiment of the present invention (FIGS. 4 and 8 (a)), and the broken line indicates the comparative example. (Fig. 8 (b)) is supported.

As is clear from FIG. 5, in the embodiment of the present invention, the automatic stop preparation control 120 is started at the same time as the automatic stop precondition is satisfied (a) in the state where the clutch 32 is engaged and the engine torque is gradually reduced. Since it is started, the timing (b) of clutch release and fuel injection stop at torque 0 starts the automatic stop preparation control 220 when the switching control 210 to the auxiliary power supply is completed (a'). ) Is earlier than that.

Normally, since the switching control 110 to the auxiliary power source is completed by the fuel injection stop (b), the engine is stopped as it is after the fuel injection is stopped.

As shown in FIG. 6, if the automatic engine stop control is started at the same time as the automatic stop precondition is satisfied (a) in the power running state, but the switching control 110 to the auxiliary power supply is not completed due to a switch failure or the like, the torque Even after the clutch is disengaged at 0 and the fuel injection is temporarily stopped (b), the fuel injection is restarted (c) and the idle rotation is continued.

In the above cases, or as shown in FIG. 7, when the engine speed has dropped to near the idle speed before the switching control 110 to the auxiliary power supply is completed (for example, due to an air conditioner request while the vehicle is stopped). In the idle operation), the idle rotation is continued until the switching control 110 to the auxiliary power source is completed, and when the idle rotation is completed, the fuel injection is stopped (b) and the engine is stopped.

If the engine is restarted before the switching control 110 to the auxiliary power supply is completed, for example, when the accelerator is re-depressed, the engine speed is equal to or higher than the idle speed. Alternatively, the starter 22) is not driven (and therefore no voltage drop occurs), fuel injection is continued or restarted, and the engine operation proceeds as it is. Therefore, there is no problem even if the switching control 110 to the auxiliary power supply is not completed.

In the above embodiment, the case where the hybrid vehicle is provided with the drive motor 4 connected to the inverter 41 and the drive battery 42 via the high voltage power supply circuit 43 has been described, but the IGS 23 is not provided. It is used for idling stop control of mild hybrid vehicles that perform assisted driving, regenerative braking, or creep driving, and engine vehicles that are equipped with an alternator instead of IGS23 and restart the engine with a constantly meshing starter. You can also.

Although some embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications and modifications can be made based on the technical idea of the present invention. I will add.

1 Vehicle 2 Engine 3 Transmission 4 Drive motor 5 Drive wheels 6 General load 7 Protected load 10 HCU
20 ECU
21 Crankshaft 22 Starter 23 ISG (Motor Generator)
24 Main battery 25 Auxiliary battery 26 Main power supply circuit 27 Auxiliary power supply circuit 30 TCU
32 Clutch 41 Inverter 42 Drive battery 43 High voltage power supply circuit SW1 1st switch SW2 2nd switch

Claims (7)

With an internal combustion engine
A clutch for connecting / releasing the output shaft of the engine and the transmission, and
A motor generator having a function of generating electricity by rotating the output shaft and a function of restarting the engine,
It is connected to the electric generator and a general load, can be connected to a protected load, is charged with the electric power generated by the electric generator, and can supply power to the electric generator, the general load, and the protected load. Main battery and
An auxiliary battery that can be connected to the motor generator and the protected load, is charged with the electric power generated by the motor generator, and can supply power to the protected load.
It is a vehicle control device equipped with
Automatic stop preparation control that gradually reduces the torque of the engine to release the clutch according to the satisfaction of the automatic stop condition of the engine, connection between the auxiliary battery and the protected load, and the auxiliary battery and the motor generator. It is configured to perform power switching control including disconnection from the machine at the same time, and to stop the engine after the completion of the control.
Vehicle control device. The vehicle control device according to claim 1, wherein the disconnection between the auxiliary battery and the motor generator is performed after the connection between the auxiliary battery and the protected load. The vehicle control device according to claim 1 or 2, wherein the connection between the auxiliary battery and the protected load is performed when the power supply voltage of the motor generator is equal to or less than a specified value. The vehicle according to any one of claims 1 to 3, which is configured to idle-rotate the engine when the disengagement between the auxiliary battery and the motor generator is not completed when the clutch is disengaged. Control device. The vehicle includes a main power supply circuit in which the electric generator and the general load are connected to the main battery, an auxiliary power supply circuit for connecting the protected load to the auxiliary battery, the main power supply circuit, and the vehicle. The first switch includes a first switch for connecting / disconnecting the auxiliary power supply circuit and a second switch for connecting / disconnecting the auxiliary power supply circuit between the first switch and the auxiliary battery. Is connected when the engine is running, but is disconnected from the automatic stop to the restart of the engine, and the second switch is disconnected when the auxiliary battery is fully charged even when the engine is running. However, the vehicle control device according to any one of claims 1 to 4, which is configured to be in a connected state when the first switch is disconnected. The vehicle control device according to any one of claims 1 to 5, wherein the vehicle is a mild hybrid vehicle capable of executing drive assist and regenerative braking of the engine by the motor generator. The vehicle includes a drive motor generator capable of transmitting power to the output shaft of the transmission without going through the engine, and a high-voltage battery connected to the drive motor generator via an inverter. The vehicle control device according to any one of claims 1 to 5, which is a hybrid vehicle capable of performing power running and regenerative braking by the drive motor generator.

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