JP7706483B2 - Hybrid vehicle control device - Google Patents

Description

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

For example, a series hybrid system includes an engine, a generator motor that uses engine power to generate electricity, a drive motor that generates the driving force for traveling, and a battery that stores the electricity supplied to the drive motor.

In a vehicle equipped with this hybrid system, when the output required of the drive motor is less than the battery's available power output, the drive motor is driven by power from the battery, and the drive force is transmitted from the drive motor to the drive wheels (EV mode). On the other hand, when the output required of the drive motor exceeds the battery's available power output, the generator motor converts the engine's power into electricity, the drive motor is driven by the power from the generator motor, and the drive motor transmits the drive force to the drive wheels (HEV mode).

When starting the engine, power from the battery is supplied to the generator motor, which operates in powered mode and motors the engine. Motoring rotates the engine's crankshaft (cranking), and when the engine speed increases to the required speed for starting, the engine's ignition plug is sparked and the engine is started.

An engine output gear is provided on the engine crankshaft, and a generator motor gear is provided on the rotating shaft of the generator motor. The engine output gear and the generator motor gear mesh together to transmit power between the engine and the generator motor. As a result, when the engine is started, the teeth of the engine output gear and the teeth of the generator motor gear may collide strongly, causing what is known as gear rattle noise. A technology has been proposed to suppress the occurrence of this gear rattle noise when the engine is started.

JP 2021-160584 A

In addition, in a series hybrid system, for example, when switching from motoring operation to firing operation, the control performs instantaneous fuel injection and ignition regardless of the intake pressure state, and combustion may occur when the intake pressure is low. In such cases, combustion in the engine may become slow, which may result in the teeth of the engine output gear clashing with the teeth of the generator motor gear.

The object of the present invention is to provide a control device for a hybrid vehicle that can suppress the generation of gear rattle noise caused by gear rattle between the engine and the generator motor when transitioning from motoring operation to firing operation.

In order to achieve the above object, a control device for a hybrid vehicle according to the present invention is a control device used in a hybrid vehicle equipped with an engine, a generator motor to which the output of the engine is transmitted, and a detector for acquiring an intake pressure of the engine, and includes: a control unit that, when switching from motoring operation to firing operation, if the intake pressure is equal to or less than a first threshold value indicating an intake pressure corresponding to a target, controls a throttle valve to open by a first predetermined amount until the intake pressure exceeds the first threshold value or a first predetermined time has elapsed. If the intake pressure is equal to or less than a second threshold value higher than the first threshold value, the control unit controls to inject fuel into the engine after the intake pressure exceeds the second threshold value or a second predetermined time longer than the first predetermined time has elapsed.

According to this configuration, the control device for the hybrid vehicle opens the throttle valve to a first predetermined opening amount until the intake pressure reaches the intake pressure corresponding to the target, so that combustion can start after the intake pressure is restored. This allows sufficient combustion in the engine and increases the engine speed, thereby suppressing gear rattle. This allows the control device for the hybrid vehicle to suppress the generation of gear rattle noise caused by gear rattle.

As a result, for example, when switching from motoring operation to firing operation, the control device of the hybrid vehicle injects fuel into the engine while ensuring sufficient intake pressure. This results in sufficient combustion within the engine, which increases the engine speed, making it possible to suppress gear rattle. As a result, the control device of the hybrid vehicle can suppress the generation of gear rattle noise caused by gear rattle.

Furthermore, for example, the motoring operation may be surplus consumption motoring operation, and the opening degree of the throttle valve may be a second predetermined amount lower than the first predetermined amount. Therefore, in surplus consumption motoring, the intake pressure is ensured and injection to the engine is started, thereby suppressing gear strike.

According to the present invention, when transitioning from motoring operation to firing operation, it is possible to suppress the occurrence of gear rattle noise caused by gear rattle between the engine and the generator motor.

FIG. 1 is a block diagram showing an example of the configuration of a hybrid vehicle to which a control device according to an embodiment of the present invention is applied. FIG. 2 is a time chart showing an example of the flow of a control operation in the control device according to one embodiment of the present invention. FIG. 3 is a flowchart showing an example of a control process in the control device according to one embodiment of the present invention.

The following describes in detail an embodiment of the present invention with reference to the attached drawings.

<Hybrid vehicle>
FIG. 1 is a block diagram showing the configuration of a hybrid vehicle 1.

The hybrid vehicle 1 is equipped with a series hybrid system 2. The hybrid system 2 includes an engine 11, a generator motor (MG1) 12, a drive motor (MG2) 13, a battery 14, and a PCU (Power Control Unit) 15.

Engine 11 is, for example, a gasoline engine. Engine 11 is equipped with a throttle body, a fuel injector that injects fuel into the intake air, and the like. The throttle body is a component that takes in fuel and air and sends them to the fuel chamber of engine 11, and is equipped with an electronic throttle valve (hereinafter also simply referred to as the throttle valve) for adjusting the amount of intake air into the combustion chamber of engine 11, a throttle position sensor that detects the opening of the electronic throttle valve, a control valve for adjusting the amount of intake air when idling, such as when the vehicle is stopped, and the like.

The generator motor 12 is, for example, a permanent magnet synchronous motor. The rotating shaft of the generator motor 12 is mechanically connected to the crankshaft of the engine 11 via a gear (not shown). For example, an engine output gear is supported on the crankshaft of the engine 11 so as not to rotate relative to the crankshaft, and a motor gear is supported on the rotating shaft of the generator motor 12 so as not to rotate relative to the crankshaft, and the engine output gear and the motor gear are meshed. The output of the engine 11 is transmitted to the generator motor 12.

The drive motor 13 is, for example, a permanent magnet synchronous motor that is larger than the generator motor 12. The rotating shaft of the drive motor 13 is connected to a drive system 16 of the hybrid vehicle 1. The drive system 16 includes a differential gear, and the power of the drive motor 13 is transmitted to the differential gear, and is then distributed and transmitted from the differential gear to drive wheels 17 consisting of the left and right front wheels or rear wheels. This causes the left and right drive wheels 17 to rotate, and the hybrid vehicle 1 moves forward or backward.

Battery 14 is a battery pack made up of multiple secondary batteries. The secondary batteries are, for example, lithium-ion batteries. Battery 14 outputs, for example, DC power of approximately 200 to 350 V (volts).

The PCU 15 is a unit for controlling the operation of the generator motor 12 and the drive motor 13, and is equipped with a first inverter 21, a second inverter 22, and a converter 23.

When starting the engine 11, the DC power output from the battery 14 is boosted by the converter 23, the boosted DC power is converted to AC power by the first inverter 21, and the AC power is supplied to the generator motor 12. This causes the generator motor 12 to perform power running, and the engine 11 is motored (cranked) by the generator motor 12 (motoring operation). When the rotation speed of the crankshaft of the engine 11 has increased to the rotation speed required for starting due to motoring, the ignition plug of the engine 11 is sparked and the engine 11 starts.

When the hybrid vehicle 1 is running, the drive motor 13 is powered and generates power.

When the output required for the drive motor 13 is smaller than the output of the battery 14, the hybrid vehicle 1 runs in EV mode. That is, the engine 11 is stopped, no power is generated by the generator motor 12, and power is supplied from the battery 14 to the drive motor 13, which is then used to drive the drive motor 13.

On the other hand, when the output required for the drive motor 13 exceeds the output of the battery 14, the hybrid vehicle 1 runs in HEV mode. That is, the engine 11 is operated and the generator motor 12 is operated to generate electricity (regenerative operation), so that the power of the engine 11 is converted to AC power by the generator motor 12. The AC power from the generator motor 12 is then converted to DC power by the first inverter 21, and the DC power output from the first inverter 21 is converted to AC power by the second inverter 22, and the AC power is supplied to the drive motor 13, thereby driving the drive motor 13.

In addition, when the remaining capacity of the battery 14 falls below a predetermined level, regardless of whether the drive motor 13 is driven or stopped, fuel is injected into the engine 11, and the generator motor 12 operates to generate electricity while the engine 11 is running (firing operation). At this time, the AC power from the generator motor 12 is converted to DC power by the first inverter 21, and the DC power output from the first inverter 21 is stepped down by the converter 23, and the stepped-down DC power is supplied to the battery 14, thereby charging the battery 14.

When the hybrid vehicle 1 decelerates, the drive motor 13 is operated in regenerative mode, and the power transmitted from the drive wheels 17 to the drive motor 13 is converted to AC power. At this time, the drive motor 13 acts as a resistor in the running drive system, and this resistance acts as a braking force (regenerative braking force) that brakes the hybrid vehicle 1. At this time, in the PCU 15, the AC power supplied from the drive motor 13 to the second inverter 22 is converted to DC power by the second inverter 22, and the DC power output from the second inverter 22 is stepped down by the converter 23. The stepped-down DC power is then supplied to the battery 14, thereby charging the battery 14.

The hybrid vehicle 1 is equipped with multiple ECUs (Electronic Control Units). Each ECU has a microcontroller unit (microcomputer), which includes, for example, a CPU, a non-volatile memory such as a flash memory, and a volatile memory such as a dynamic random access memory (DRAM).

The multiple ECUs are connected to enable two-way communication using the CAN (Controller Area Network) communication protocol. Various sensors necessary for control are connected to each ECU, and detection signals from the connected sensors are input. In addition to the detection signals input from the various sensors, information necessary for control is also input from other ECUs to each ECU.

Of the multiple ECUs, FIG. 1 shows ECU 31 and ECU 32 that control the hybrid system 2. ECU 30, which includes ECU 31 and ECU 32, is an example of a control device for the hybrid vehicle 1.

An accelerator sensor 33 and a vehicle speed sensor 34 are connected to the ECU 31. The accelerator sensor 33 outputs a detection signal corresponding to the amount of operation of the accelerator pedal operated by the driver. The vehicle speed sensor 34 outputs a detection signal, which is a pulse signal synchronized with the rotation of a rotating body that rotates as the hybrid vehicle 1 travels.

The ECU 32 is also connected to an intake pressure sensor 35. The intake pressure sensor 35 detects the intake pressure of the engine 11 and outputs a detection signal indicating the detected intake pressure. The intake pressure sensor 35 is an example of a detector. The intake pressure may be calculated by the ECU 32 from the opening degree of the throttle body (throttle opening degree).

The ECU 31 obtains the accelerator opening, which is the ratio of the current accelerator pedal operation amount to the maximum accelerator pedal operation amount, from the detection signal of the accelerator sensor 33. The ECU 31 also obtains the frequency of the detection signal (pulse signal) from the detection signal of the vehicle speed sensor 34, and converts the frequency into vehicle speed.

The ECU 32 includes an acquisition unit, a determination unit, a timing unit, and a control unit. The acquisition unit acquires the intake pressure of the engine 11 from the intake pressure sensor 35. The determination unit determines whether the intake pressure acquired by the acquisition unit is equal to or lower than a first threshold value indicating the intake pressure corresponding to the target. The determination unit also determines whether the intake pressure acquired by the acquisition unit is equal to or lower than a second threshold value higher than the first threshold value. Furthermore, the determination unit determines whether the time measured by the timing unit has passed a first predetermined time. The determination unit also determines whether the time measured by the timing unit has passed a second predetermined time.

The timer measures a predetermined time from the time when the intake pressure is acquired. The controller controls the throttle valve to open to a first predetermined amount. The controller also controls the throttle valve to close. Furthermore, the controller controls the fuel injector (engine) to inject fuel. Note that the functions of the ECU 32 are not limited to these.

The flow of control operations in the ECU 32 will now be described with reference to FIG. 2. FIG. 2 is a time chart showing an example of the flow of control operations in the control device. The timing chart shown in FIG. 2 is a timing chart for switching from motoring operation to firing operation in the hybrid system 2.

In the hybrid system 2, switching from motoring operation to firing operation occurs, for example, when a user requests heating of the air conditioning of the hybrid vehicle 1. Note that the operation of switching from motoring operation to firing operation is not limited to this.

The timing chart shown in Figure 2 has time T on the horizontal axis, and the vertical axis indicates the operating state, intake pressure, throttle opening, and fuel injection state. In Figure 2, the fuel injection state indicates, for example, a state in which fuel is not injected (fuel cut) and a state in which fuel is injected.

First, in the hybrid system 2, when switching from motoring operation to firing operation, the acquisition unit of the ECU 32 acquires the intake pressure of the engine 11 from the intake pressure sensor 35. Then, when the intake pressure acquired by the acquisition unit is equal to or lower than a first threshold value Th1 indicating an intake pressure corresponding to a target, the control unit of the ECU 32 controls the throttle valve to open by a first predetermined amount P1 until the intake pressure exceeds the first threshold value Th1 or until a first predetermined time T1 has elapsed.

In addition, when the intake pressure is equal to or lower than a second threshold Th2 that is higher than the first threshold Th1, the control unit of the ECU 32 controls the fuel injector (engine) to inject fuel when the intake pressure exceeds the second threshold Th2 or after a second predetermined time T2 different from the first predetermined time T1 has elapsed. The second predetermined time T2 is, for example, longer than the first predetermined time T1.

The motoring operation in FIG. 2 is surplus consumption motoring operation. Surplus consumption motoring operation is an operation in which the battery 14 is already fully charged, and the power obtained by regenerative braking is supplied to the generator motor 12, which operates as an electric motor to rotate and drive the engine 11, thereby consuming surplus power. In addition, the opening degree of the throttle valve during surplus consumption motoring operation is a second predetermined amount P2 that is lower than the first predetermined amount P1.

Next, the flow of control processing in the ECU 32 will be described with reference to FIG. 3. FIG. 3 is a flowchart showing an example of control processing in the control device. Note that the flowchart shown in FIG. 3 is a flowchart for switching from motoring operation to firing operation in the hybrid system 2.

The acquisition unit of the ECU 32 acquires the intake pressure of the engine 11 from the intake pressure sensor 35 (step S31). The timer unit of the ECU 32 starts timing based on the time when the intake pressure was acquired. Next, the determination unit of the ECU 32 determines whether the intake pressure acquired by the acquisition unit is equal to or less than a first threshold value Th1 indicating an intake pressure corresponding to the target (step S32). Here, if the determination unit of the ECU 32 determines that the acquired intake pressure exceeds the first threshold value Th1 (step S32: No), the process proceeds to step S38. On the other hand, if the determination unit of the ECU 32 determines that the acquired intake pressure is equal to or less than the first threshold value Th1 (step S32: Yes), the process proceeds to step S33.

In step S33, the control unit of the ECU 32 controls the throttle valve to open by a first predetermined amount P1 (step S33). Next, the acquisition unit of the ECU 32 acquires the intake pressure of the engine 11 from the intake pressure sensor 35 (step S34). Next, the determination unit of the ECU 32 determines whether the intake pressure acquired by the acquisition unit is equal to or lower than a first threshold value Th1 indicating the intake pressure corresponding to the target (step S35).

Here, if the judgment unit of the ECU 32 judges that the acquired intake pressure exceeds the first threshold value Th1 (step S35: No), the process proceeds to step S38. On the other hand, if the judgment unit of the ECU 32 judges that the acquired intake pressure is equal to or less than the first threshold value Th1 (step S35: Yes), the process proceeds to step S36.

In step S36, the judgment unit of ECU 32 judges whether the time measured by the timer has passed the first predetermined time T1 (step S36). If the judgment unit of ECU 32 judges that the time measured by the timer has not passed the first predetermined time T1 (step S36: No), the process returns to step S34. On the other hand, if the judgment unit of ECU 32 judges that the time measured by the timer has passed the first predetermined time T1 (step S36: Yes), the process proceeds to step S37. In step S37, the control unit of ECU 32 controls the throttle valve to close (step S37).

Next, the determination unit of the ECU 32 determines whether the intake pressure acquired by the acquisition unit is equal to or lower than a second threshold value Th2 that is higher than the first threshold value Th1 (step S38). If the determination unit of the ECU 32 determines that the acquired intake pressure exceeds the second threshold value Th2 (step S38: No), the process proceeds to step S41. On the other hand, if the determination unit of the ECU 32 determines that the acquired intake pressure is equal to or lower than the second threshold value Th2 (step S38: Yes), the process proceeds to step S39.

In step S39, the judgment unit of ECU 32 judges whether the time measured by the timer has passed a second predetermined time T2 different from the first predetermined time T1 (step S39). If the judgment unit of ECU 32 judges that the time measured by the timer has not passed the second predetermined time T2 (step S39: No), the process proceeds to step S40. On the other hand, if the judgment unit of ECU 32 judges that the time measured by the timer has passed the second predetermined time T2 (step S39: Yes), the process proceeds to step S41.

In step S40, the acquisition unit of the ECU 32 acquires the intake pressure of the engine 11 from the intake pressure sensor 35 (step S40). In step S41, the control unit of the ECU 32 controls the engine 11 to inject fuel (step S41). When step S41 ends, this process ends.

<Effects of this embodiment>
As described above, when switching from motoring operation to firing operation, the control device of the hybrid vehicle 1 in this embodiment controls the throttle valve to open by a first predetermined amount P1 if the intake pressure is equal to or lower than the first threshold value Th1 indicating the intake pressure corresponding to the target until the intake pressure exceeds the first threshold value Th1 or the first predetermined time T1 has elapsed.

Therefore, according to the present invention, the control device of the hybrid vehicle 1 opens the throttle valve to the opening of the first predetermined amount P1 until the intake pressure reaches the target, so that combustion can start after the intake pressure is restored. This ensures sufficient combustion in the engine, and the engine 11 speed increases, making it possible to suppress gear rattle. Therefore, the control device of the hybrid vehicle 1 can suppress the generation of gear rattle noise due to gear rattle.

In addition, by opening the throttle valve before fuel injection begins for the engine 11, the time delay until fuel injection can be reduced, reducing delays in system requirements and, for example, suppressing the acceleration effects caused by power generation delays.

Furthermore, when the intake pressure is equal to or lower than a second threshold value Th2 that is higher than the first threshold value Th1, control is performed so that fuel is injected into the engine 11 when the intake pressure exceeds the second threshold value Th2 or after a second predetermined time T2 different from the first predetermined time T1 has elapsed.

Therefore, according to the present invention, the control device of the hybrid vehicle 1 injects fuel into the engine 11 while ensuring sufficient intake pressure. This ensures sufficient combustion in the engine, increasing the rotation speed of the engine 11 and suppressing gear rattle. Therefore, the control device of the hybrid vehicle 1 can suppress the generation of gear rattle noise caused by gear rattle.

Moreover, the motoring operation is surplus consumption motoring operation, and the opening degree of the throttle valve is a second predetermined amount P2 that is lower than the first predetermined amount P1. Therefore, according to the present invention, in surplus consumption motoring, the intake pressure is ensured and injection to the engine 11 is started, thereby suppressing gear strike.

<Modification>
Although one embodiment of the present invention has been described above, the present invention can be embodied in other forms.

For example, in the above embodiment, a form was described in which the throttle valve is controlled to open by a first predetermined amount P1 in order to increase the intake pressure in the firing operation state. In a modified example, the throttle valve may be controlled to open by a first predetermined amount P1 in order to increase the intake pressure even in the motoring operation state. By increasing the intake pressure from the motoring operation state, combustion in the engine is sufficient in the firing operation, and the rotation speed of the engine 11 increases, thereby suppressing gear strike.

In this embodiment, the control device is described as being applied to a series type hybrid system 2, but is not limited to this. For example, the control device can be applied to a series-parallel type hybrid system in which a power split mechanism is provided in the vehicle and both the engine and the motor are used as power sources, a mild type hybrid system that uses the motor as an auxiliary motor for the engine (e.g., an ISG (Integrated Starter Generator)), and a parallel type hybrid system.

Although the embodiment of the present invention has been described above, the above-mentioned embodiment is presented as an example and is not intended to limit the scope of the present invention. This new embodiment can be embodied in various other forms. Furthermore, various omissions, substitutions, and modifications can be made without departing from the gist of the invention. Furthermore, this embodiment is included in the scope and gist of the invention, and is included in the scope of the invention and its equivalents described in the claims.

1: Hybrid vehicle 11: Engine 12: Generator motor 13: Drive motor 14: Battery
15: PCU
32: ECU (control device, acquisition unit, judgment unit, timing unit)

Claims (2)

A control device for use in a hybrid vehicle equipped with an engine, a generator motor to which an output of the engine is transmitted, and a detector for acquiring an intake pressure of the engine,
a control unit that controls the throttle valve to open by a first predetermined amount when the intake pressure is equal to or lower than a first threshold value indicating an intake pressure corresponding to a target when switching from a motoring operation to a firing operation, until the intake pressure exceeds the first threshold value or a first predetermined time has elapsed;
Equipped with
When the intake pressure is equal to or lower than a second threshold value that is higher than the first threshold value, the control unit performs control to inject fuel into the engine after the intake pressure exceeds the second threshold value or after a second predetermined time that is longer than the first predetermined time has elapsed.
A control device for a hybrid vehicle. The motoring operation is a surplus consumption motoring operation,
The opening degree of the throttle valve is a second predetermined amount that is lower than the first predetermined amount.
The control device for a hybrid vehicle according to claim 1 .

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