Hybrid vehicle control device

Abstract

To suppress the occurrence of the rattling sound due to rattling between gears connecting an engine with a power generation motor when shifting from motoring driving to firing driving.SOLUTION: A control device used in a hybrid vehicle equipped with an engine, a power generation motor that transmits the output of the engine and a detector that acquires the intake pressure of the engine includes a control unit which controls the opening degree of a throttle valve to a first prescribed amount until the intake pressure exceeds the first threshold or the first prescribed time elapses when switching from motoring driving to firing driving and the intake pressure is equal to or less than a first threshold that indicates the intake pressure corresponding to the target.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a control device for a hybrid vehicle.

Background Art

[0002] For example, a series hybrid system includes an engine, a power generation motor that generates electric power using the power of the engine, a drive motor that generates a driving force for running, and a battery that stores electric power supplied to the drive motor.

[0003] In a vehicle equipped with such a hybrid system, when the output required by the drive motor is smaller than the output-capable power of the battery, the drive motor is driven by the power from the battery, and the driving force is transmitted from the drive motor to the drive wheels (EV mode). On the other hand, when the output required by the drive motor exceeds the output-capable power of the battery, the power of the engine is converted into electric power by the power generation motor, the drive motor is driven by the power from the power generation motor, and the driving force is transmitted from the drive motor to the drive wheels (HEV mode).

[0004] When starting the engine, the electric power from the battery is supplied to the power generation motor, the power generation motor is operated in power running, and the engine is motored by the power generation motor. By motoring, the crankshaft of the engine rotates (cranking), and when the rotational speed rises to the rotational speed required for starting, the spark plug of the engine is sparked and the engine is started.

[0005] An engine output gear is provided on the crankshaft of the engine, a power generation motor gear is provided on the rotating shaft of the power generation motor, and power is transmitted between the engine and the power generation motor by meshing the engine output gear and the power generation motor gear. Therefore, when starting the engine, the teeth of the engine output gear and the teeth of the power generation motor gear may strongly collide, generating a so-called tooth impact sound. Technologies for suppressing the generation of this tooth impact sound during engine starting have been proposed.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2021-160584 [Summary of the Invention] [Problems to be Solved by the Invention]

[0007] In a series hybrid system, for example, when shifting from motoring operation to firing operation, in the control of performing immediate fuel injection and ignition regardless of the intake pressure state, combustion may occur in a state where the intake pressure is low. In that case, the combustion in the engine becomes slow, and it may lead to tooth engagement between the teeth of the engine output gear and the teeth of the generator motor gear.

[0008] An object of the present invention is to provide a control device for a hybrid vehicle that can suppress the generation of tooth engagement noise due to tooth engagement between gears connecting an engine and a generator motor when shifting from motoring operation to firing operation. [Means for Solving the Problems]

[0009] 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 the intake pressure of the engine. When switching from motoring operation to firing operation, when the intake pressure is equal to or lower than a first threshold value indicating an intake pressure corresponding to a target, or until the intake pressure exceeds the first threshold value or a first predetermined time elapses, a control unit that controls to open the throttle valve by a first predetermined amount of opening. 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 controls the engine to inject fuel when the intake pressure exceeds the second threshold value or after a second predetermined time that is longer than the first predetermined time has elapsed.

[0010] According to this configuration, the control device of the hybrid vehicle opens the throttle valve to a first predetermined opening until the intake pressure reaches the intake pressure corresponding to the target. Therefore, combustion can be started after the intake pressure recovers. As a result, the combustion in the engine becomes sufficient, and the engine speed increases, so that the gear clash can be suppressed. Thereby, the control device of the hybrid vehicle can suppress the generation of the gear clash noise due to the gear clash.

[0012] Thereby, for example, when switching from the motoring operation to the firing operation, the control device of the hybrid vehicle injects fuel into the engine in a state where the intake pressure is sufficiently secured. Therefore, the combustion in the engine becomes sufficient, and the engine speed increases, so that the gear clash can be suppressed. Therefore, the control device of the hybrid vehicle can suppress the generation of the gear clash noise due to the gear clash.

[0013] Furthermore, for example, the motoring operation may be an excess 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 the excess consumption motoring, the gear clash can be suppressed by securing the intake pressure and starting the injection to the engine.

Advantages of the Invention

[0014] According to the present invention, when shifting from the motoring operation to the firing operation, it is possible to suppress the generation of the gear clash noise due to the gear clash between the gears connecting the engine and the generator motor.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Embodiment for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0017] <Hybrid Vehicle> FIG. 1 is a block diagram showing the configuration of a hybrid vehicle 1.

[0018] The hybrid vehicle 1 is equipped with a series hybrid system 2. The hybrid system 2 includes an engine 11, a power generation motor (MG1) 12, a drive motor (MG2) 13, a battery 14, and a PCU (Power Control Unit) 15.

[0019] The engine 11 is, for example, a gasoline engine. The engine 11 includes a throttle body and a fuel injector that injects fuel into the intake air. The throttle body is a component that takes in fuel and air and sends it to the fuel chamber of the engine 11, and includes an electronic throttle valve (hereinafter also simply referred to as a throttle valve) for adjusting the amount of intake air into the combustion chamber of the engine 11, a throttle position sensor for detecting the opening degree of the electronic throttle valve, and a control valve for adjusting the intake air amount during idling such as when the engine stops.

[0020] The power generation motor 12 is, for example, a permanent magnet synchronous motor. The rotating shaft of the power generation 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 each other, a motor gear is supported on the rotating shaft of the power generation motor 12 so as not to rotate relative to each other, and the engine output gear and the motor gear are meshed with each other. The output of the engine 11 is transmitted to the power generation motor 12.

[0021] The drive motor 13 is, for example, a permanent magnet synchronous motor larger than the power generation motor 12. The rotating shaft of the drive motor 13 is connected to the 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 distributed from the differential gear to the drive wheels 17 composed of the left and right front wheels or rear wheels and then transmitted. Thereby, the left and right drive wheels 17 rotate, and the hybrid vehicle 1 moves forward or backward.

[0022] The battery 14 is a battery pack combining a plurality of secondary batteries. The secondary battery is, for example, a lithium-ion battery. The battery 14 outputs DC power of, for example, about 200 to 350 V (volts).

[0023] The PCU 15 is a unit for controlling the driving of the power generation motor 12 and the drive motor 13, and includes a first inverter 21, a second inverter 22, and a converter 23.

[0024] When the engine 11 is started, the DC power output from the battery 14 is boosted by the converter 23, the boosted DC power is converted into AC power by the first inverter 21, and the AC power is supplied to the power generation motor 12. Thereby, the power generation motor 12 is operated in power running mode, and the engine 11 is motored (cranked) by the power generation motor 12 (motoring operation). When the rotational speed of the crankshaft of the engine 11 has increased to the rotational speed required for starting by motoring and the spark plug of the engine 11 is sparked, the engine 11 starts.

[0025] When the hybrid vehicle 1 is running, the drive motor 13 is operated in power running mode, and the drive motor 13 generates power.

[0026] When the output required by 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, power generation by the power generation motor 12 is not performed, power is supplied from the battery 14 to the drive motor 13, and the drive motor 13 is driven by that power.

[0027] On the other hand, when the output required by 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 put into operation, and the power generation motor 12 is operated for power generation (regenerative operation), so that the power of the engine 11 is converted into AC power by the power generation motor 12. Then, the AC power from the power generation motor 12 is converted into DC power by the first inverter 21, and the DC power output from the first inverter 21 is converted into AC power by the second inverter 22, and the drive motor 13 is driven by supplying the AC power to the drive motor 13.

[0028] Also, when the remaining capacity of the battery 14 drops below a predetermined level, regardless of whether the drive motor 13 is driven or stopped, fuel is injected into the engine 11, and the power generation motor 12 is operated for power generation (firing operation) while the engine 11 is running. At this time, the AC power from the power generation motor 12 is converted into 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 to charge the battery 14.

[0029] During deceleration of the hybrid vehicle 1, the drive motor 13 is operated for regeneration, and the power transmitted from the drive wheels 17 to the drive motor 13 is converted into AC power. At this time, the drive motor 13 becomes a resistance of the running drive system, and the resistance acts as a braking force (regenerative braking force) for braking 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 into DC power by the second inverter 22, and the DC power output from the second inverter 22 is stepped down by the converter 23. Then, the stepped-down DC power is supplied to the battery 14 to charge the battery 14.

[0030] The hybrid vehicle 1 is equipped with a plurality of ECUs (Electronic Control Units). Each ECU includes a microcomputer (Micro Controller Unit), and the microcomputer incorporates non-volatile memories such as a CPU and flash memory, and volatile memories such as DRAM (Dynamic Random Access Memory).

[0031] The plurality of ECUs are connected so as to enable two-way communication according to the CAN (Controller Area Network) communication protocol. Each ECU is connected to various sensors necessary for control, and detection signals of the connected sensors are input. Also, in addition to the detection signals input from various sensors, information necessary for control is input to each ECU from other ECUs.

[0032] FIG. 1 shows the ECUs 31 and 32 that control the hybrid system 2 among the plurality of ECUs. The ECU 30 including the ECUs 31 and 32 is an example of a control device for the hybrid vehicle 1.

[0033] 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 operation amount of the accelerator pedal depressed by the driver (operator). The vehicle speed sensor 34 outputs a pulse signal synchronized with the rotation of a rotating body that rotates as the hybrid vehicle 1 travels as a detection signal.

[0034] Also, an intake pressure sensor 35 is connected to the ECU 32. 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. Note that the intake pressure may be calculated by the ECU 32 from the opening degree of the throttle body (throttle opening).

[0035] In the ECU 31, the throttle opening, which is the ratio of the current operation amount of the accelerator pedal to the maximum operation amount, is obtained from the detection signal of the accelerator sensor 33. Also, in the ECU 31, the frequency of the detection signal (pulse signal) is obtained from the detection signal of the vehicle speed sensor 34, and the frequency is converted into the vehicle speed.

[0036] 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 less than or equal to a first threshold value indicating the target intake pressure. Also, the determination unit determines whether the intake pressure acquired by the acquisition unit is less than or equal to a second threshold value higher than the first threshold value. Furthermore, the determination unit determines whether the time measured by the timing unit has elapsed the first predetermined time. Also, the determination unit determines whether the time measured by the timing unit has elapsed the second predetermined time.

[0037] The timing unit measures a predetermined time determined in advance from the time when the intake pressure is acquired. The control unit controls to open the throttle valve by a first predetermined amount of opening. Also, the control unit controls to close the throttle valve. Furthermore, the control unit controls the fuel injector (engine) to inject fuel. Note that the functions provided in the ECU 32 are not limited to this.

[0038] Here, with reference to FIG. 2, the flow of the control operation in the ECU 32 will be described. FIG. 2 is a time chart showing an example of the flow of the control operation in the control device. The timing chart shown in FIG. 2 is a timing chart when switching from the motoring operation to the firing operation in the hybrid system 2.

[0039] In the hybrid system 2, when switching from the motoring operation to the firing operation, for example, it is the case where the air conditioner of the hybrid vehicle 1 is requested to be heated by the user's operation. Note that the switching operation from the motoring operation to the firing operation is not limited to this.

[0040] The timing chart shown in FIG. 2 has the horizontal axis as time T and the vertical axis shows the operating state, intake pressure, throttle opening, and fuel injection state respectively. In FIG. 2, the fuel injection state shows, for example, a state where fuel is not being injected (fuel cut) and a state where fuel is being injected.

[0041] 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 corresponding to the target, the control unit of the ECU 32 controls the throttle valve to open by a first predetermined amount P1 of opening until the intake pressure exceeds the first threshold value Th1 or a first predetermined time T1 elapses.

[0042] Also, when the intake pressure is equal to or lower than a second threshold value Th2 higher than the first threshold value Th1, the control unit of the ECU 32 controls the fuel injector (engine) to inject fuel after 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. The second predetermined time T2 is, for example, a longer time than the first predetermined time T1.

[0043] Also, the motoring operation in FIG. 2 is an excess consumption motoring operation. The excess consumption motoring operation is an operation in which the capacity of the battery 14 is already fully charged, the power obtained by regenerative braking is deliberately supplied to the power generation motor 12, the power generation motor 12 is operated as an electric motor to rotationally drive the engine 11, and the excess power is consumed. Also, the opening of the throttle valve during the excess consumption motoring operation is a second predetermined amount P2 lower than the first predetermined amount P1.

[0044] Next, with reference to FIG. 3, the control process flow in the ECU 32 will be described. FIG. 3 is a flowchart showing an example of the control process in the control device. Note that the flowchart shown in FIG. 3 is the flowchart when switching from the motoring operation to the firing operation in the hybrid system 2.

[0045] The acquisition unit of the ECU 32 acquires the intake pressure of the engine 11 from the intake pressure sensor 35 (step S31). Also, the timing unit of the ECU 32 starts timing based on the time when the intake pressure is acquired. Subsequently, the determination unit of the ECU 32 determines whether the intake pressure acquired by the acquisition unit is less than or equal to a first threshold value Th1 indicating the intake pressure corresponding to the target (step S32). Here, when it is determined that the intake pressure acquired by the determination unit of the ECU 32 exceeds the first threshold value Th1 (step S32: No), the process proceeds to step S38. On the other hand, when it is determined that the intake pressure acquired by the determination unit of the ECU 32 is less than or equal to the first threshold value Th1 (step S32: Yes), the process proceeds to step S33.

[0046] In step S33, the control unit of the ECU 32 controls the throttle valve to open to an opening degree of a first predetermined amount P1 (step S33). Subsequently, the acquisition unit of the ECU 32 acquires the intake pressure of the engine 11 from the intake pressure sensor 35 (step S34). Subsequently, the determination unit of the ECU 32 determines whether the intake pressure acquired by the acquisition unit is less than or equal to the first threshold value Th1 indicating the intake pressure corresponding to the target (step S35).

[0047] Here, when it is determined that the intake pressure acquired by the determination unit of the ECU 32 exceeds the first threshold value Th1 (step S35: No), the process proceeds to step S38. On the other hand, when it is determined that the intake pressure acquired by the determination unit of the ECU 32 is less than or equal to the first threshold value Th1 (step S35: Yes), the process proceeds to step S36.

[0048] In step S36, the determination unit of ECU 32 determines whether the time measured by the timing unit has elapsed the first predetermined time T1 (step S36). Here, if the determination unit of ECU 32 determines that the time measured by the timing unit has not elapsed the first predetermined time T1 (step S36: No), the process returns to step S34. On the other hand, if the determination unit of ECU 32 determines that the time measured by the timing unit has elapsed 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).

[0049] Subsequently, the determination unit of ECU 32 determines whether the intake air pressure acquired by the acquisition unit is less than or equal to the second threshold Th2 which is higher than the first threshold Th1 (step S38). Here, if the determination unit of ECU 32 determines that the acquired intake air pressure exceeds the second threshold Th2 (step S38: No), the process proceeds to step S41. On the other hand, if the determination unit of ECU 32 determines that the acquired intake air pressure is less than or equal to the second threshold Th2 (step S38: Yes), the process proceeds to step S39.

[0050] In step S39, the determination unit of ECU 32 determines whether the time measured by the timing unit has elapsed the second predetermined time T2 which is different from the first predetermined time T1 (step S39). Here, if the determination unit of ECU 32 determines that the time measured by the timing unit has not elapsed the second predetermined time T2 (step S39: No), the process proceeds to step S40. On the other hand, if the determination unit of ECU 32 determines that the time measured by the timing unit has elapsed the second predetermined time T2 (step S39: Yes), the process proceeds to step S41.

[0051] In step S40, the acquisition unit of ECU 32 acquires the intake air pressure of engine 11 from the intake air pressure sensor 35 (step S40). In step S41, the control unit of ECU 32 controls to inject fuel into engine 11 (step S41). When step S41 ends, this process ends.

[0052] <The effects of this embodiment> As described above, when the control device of the hybrid vehicle 1 according to the present embodiment switches from motoring operation to firing operation, if the intake pressure is equal to or lower than a first threshold Th1 indicating the intake pressure corresponding to the target, or until the intake pressure exceeds the first threshold Th1 or a first predetermined time T1 elapses, control is performed to open the throttle valve by an opening degree of a first predetermined amount P1.

[0053] Therefore, according to the present invention, the control device of the hybrid vehicle 1 opens the throttle valve to an opening degree of the first predetermined amount P1 until the intake pressure reaches the intake pressure corresponding to the target, so that combustion can be started after the intake pressure recovers. As a result, combustion in the engine becomes sufficient, and the rotational speed of the engine 11 increases, so that knocking can be suppressed. Therefore, the control device of the hybrid vehicle 1 can suppress the generation of knocking noise due to knocking.

[0054] In addition, by opening the throttle valve in advance before starting fuel injection to the engine 11, the time delay until fuel injection can also be reduced, the delay with respect to system requirements can be reduced, and for example, the acceleration influence due to power generation delay can be suppressed.

[0055] Furthermore, when the intake pressure is equal to or lower than a second threshold Th2 higher than the first threshold Th1, or after the intake pressure exceeds the second threshold Th2 or a second predetermined time T2 different from the first predetermined time T1 elapses, control is performed to inject fuel into the engine 11.

[0056] Therefore, according to the present invention, the control device of the hybrid vehicle 1 injects fuel into the engine 11 in a state where the intake pressure is sufficiently ensured. As a result, combustion in the engine becomes sufficient, and the rotational speed of the engine 11 increases, so that knocking can be suppressed. Therefore, the control device of the hybrid vehicle 1 can suppress the generation of knocking noise due to knocking.

[0057] Further, the motoring operation is an excess 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 excess consumption motoring, by ensuring the intake pressure and starting injection with respect to the engine 11, knocking can be suppressed.

[0058] <Modification Example> As described above, an embodiment of the present invention has been described, but the present invention can also be implemented in other forms.

[0059] For example, in the above-described embodiment, in the firing operation state, the control for opening the throttle valve to the opening degree of the first predetermined amount P1 to increase the intake pressure has been described. In the modification example, also in the motoring operation state, the control may be performed to open the throttle valve to the opening degree of the first predetermined amount P1 to increase the intake pressure. By increasing the intake pressure from the motoring operation, the combustion in the engine during the firing operation becomes sufficient, and the rotational speed of the engine 11 increases, so that knocking can be suppressed.

[0060] Note that, although the present embodiment has described the control device applied to the series-type hybrid system 2, the present invention is not limited thereto. For example, it can be applied to a series-parallel hybrid system provided with a power split mechanism in a vehicle and using both an engine and a motor as power sources, a mild hybrid system used as an auxiliary motor (for example, ISG (Integrated Starter Generator)) of an engine, a parallel hybrid system, and the like.

[0061] The embodiments of the present invention have been described above. However, the above-described embodiments are presented as examples and are not intended to limit the scope of the present invention. This novel embodiment can be implemented in various other forms. Also, various omissions, substitutions, and changes can be made without departing from the gist of the invention. Further, this embodiment is included in the scope and gist of the invention, and is included in the invention described in the claims and the equivalent scope thereof.

Explanation of Reference Numerals

[0062] 1: Hybrid vehicle 11: Engine 12: Power generation motor 13: Drive motor 14: Battery 15: PCU 32: ECU (Control device, acquisition unit, determination unit, time measurement unit)

Claims

1. A control device for a hybrid vehicle equipped with an engine, a power generation motor to which the output of the engine is transmitted, and a detector for obtaining the intake pressure of the engine, comprising: When switching from motoring operation to firing operation, when the intake pressure is equal to or lower than a first threshold value indicating an intake pressure corresponding to a target, until the intake pressure exceeds the first threshold value or a first predetermined time has elapsed, a control unit that controls the throttle valve to open by a first predetermined amount of opening; Comprising; When the intake pressure is equal to or lower than a second threshold value higher than the first threshold value, after the intake pressure exceeds the second threshold value or after a second predetermined time longer than the first predetermined time has elapsed, the control unit controls the engine to inject fuel; A control device for a hybrid vehicle.

2. The motoring operation is surplus consumption motoring operation, The opening degree of the throttle valve is a second predetermined amount lower than the first predetermined amount, The control device for a hybrid vehicle according to claim 1.

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