Hybrid vehicle control device

Abstract

To provide a hybrid vehicle control device capable of suppressing giving discomfort and anxiety to a driver when power consumption of a generator is increased by motoring an engine.SOLUTION: An ECU increases engine loss torque in the same engine rotation speed by motoring an engine by a generator during charge restriction and during vehicle slip-down, and performing control to a state where an exhaust valve is not completely closed by a decompression device. As a result, the engine rotation speed required for obtaining the same engine loss torque (generator power consumption) is reduced.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] Patent Document 1 proposes a control device for a hybrid vehicle that includes an engine, a generator, a battery, a drive machine, a direct power distribution control means, and a vehicle skid response control means, in which the direct power distribution control means controls the generated power in accordance with a drive request so that the actual power generated by the generator is consumed as drive power for the drive machine in the right amount, and the vehicle skid response control means controls the drive machine to regenerate and controls the generator to power when the sign of the drive torque command value is not reversed but the sign of the drive rotation speed is reversed during power generation control by direct power distribution. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-51457 Summary of the Invention [Problem to be solved by the invention]

[0004] To ensure climbing performance even on steep slopes, it is necessary to increase the power consumption of the generator by motoring the engine at high revolutions using the generator to increase engine power loss.However, engine noise generated by rotating the engine at high speed can cause discomfort and anxiety to the driver.

[0005] The present invention has been made in consideration of the above facts, and aims to provide a hybrid vehicle control device that can suppress discomfort and anxiety felt by the driver when motoring the engine to increase the power consumption of the generator. [Means for solving the problem]

[0006] A hybrid vehicle control device according to a first aspect is mounted on a hybrid vehicle that includes an engine, a generator that generates electricity by driving the engine and is capable of motoring the engine, a battery that stores the electricity generated by the generator, a drive machine that is driven by the electricity stored in the battery, and a decompression device that prevents the exhaust valve of the engine from closing completely, and includes a control unit that controls the engine, the generator, the drive machine, and the decompression device, and the control unit motors the engine using the generator during charge restriction and when the vehicle is rolling downhill, and controls the decompression device to prevent the exhaust valve from closing completely.

[0007] According to the first aspect, the engine is motored by the generator during charge restriction and while the vehicle is rolling downhill, and the decompression device controls the exhaust valve so that it does not close completely, which increases engine torque loss compared to when the engine is motored with the exhaust valve fully closed, thereby reducing the engine speed when motoring, thereby reducing engine noise that makes the driver feel uncomfortable or uneasy. [Effects of the Invention]

[0008] As described above, according to the present invention, a hybrid vehicle control device can be provided that can suppress the driver from feeling uncomfortable or uneasy when the engine is motored to increase the power consumption of the generator. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram showing a schematic configuration of a hybrid vehicle equipped with a hybrid control device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a block diagram showing the configuration of an ECU. [Figure 3] FIG. 10 is a diagram showing an example of calculation results obtained by engine simulation. [Figure 4]4A to 4C are diagrams illustrating an example of a vehicle speed, an accelerator opening, a motor torque, an engine torque, an engine rotation speed, and a generator torque. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described in detail with reference to the accompanying drawings, in which: Figure 1 is a diagram showing a schematic configuration of a hybrid vehicle equipped with a hybrid control device according to this embodiment.

[0011] The hybrid vehicle 10 mainly comprises an engine 12, axles 14, drive wheels 16, a generator 18 as an example of an electric power generator, a motor 20 as an example of a drive machine, a power split mechanism 22, an inverter 24, a battery 26, and an ECU 28 as an example of a control unit.

[0012] Except for the decompression device 30, the engine 12 is a typical internal combustion engine, and its operation is controlled by the ECU 28. That is, the engine 12 is equipped with various sensors such as a throttle position sensor for detecting the throttle opening, an air flow meter or vacuum sensor for detecting the intake amount, a position sensor for detecting the crank angle, a cam angle, etc., an intake air temperature sensor for detecting the intake air temperature, a water temperature sensor for detecting the coolant temperature, and an air-fuel ratio sensor for detecting the air-fuel ratio, as well as an actuator for opening and closing the throttle, and the ECU 28 controls the fuel injection amount, ignition timing, the various actuators, etc. based on the detection results of the various sensors, thereby controlling the operation of the engine 12. Note that engine control itself is a well-known technique, so a detailed description thereof will be omitted.

[0013] The decompression device 30 includes an actuator that prevents the exhaust valve of the engine 12 from completely closing, and by driving the actuator, the exhaust valve opens slightly by a predetermined amount, preventing it from completely closing. The decompression device 30 can prevent the exhaust valve of the engine 12 from completely closing by applying the mechanism described in Japanese Patent No. 7020235, for example.

[0014] The axle 14 comprises, for example, a transmission, a drive shaft, a differential gear, etc., and transmits the power of the engine 12 or the motor 20 to the drive wheels 16 .

[0015] The generator 18 mainly functions as a generator for charging the battery 26 or for supplying power to the motor 20, and generates power by driving the engine 12. The generator 18 is also capable of motoring the engine 12 using regenerative power from the motor 20.

[0016] The motor 20 is connected to the axle 14 and is driven by the electric power stored in the battery 26 , and functions as an electric motor that outputs the driving force of the hybrid vehicle 10 .

[0017] The power split mechanism 22 distributes the output of the engine 12 to the generator 18 and the axle 14 by means of a planetary gear mechanism.

[0018] The inverter 24 functions as a DC / AC converter and controls the input and output of power between the battery 26 and the generator 18 or motor. That is, when using power from the battery 26 to drive the generator 18 or motor, the inverter 24 converts DC to AC and supplies power from the battery 26 to the motor generator, and when using power generated by the motor generator to charge the battery 26, the inverter 24 converts the generated power to DC and charges the battery 26.

[0019] As shown in FIG. 2, the ECU 28 is configured as a general microcomputer including a CPU (Central Processing Unit) 28A, a ROM (Read Only Memory) 28B, a RAM (Random Access Memory) 28C, a storage 28D, and an I / F (Interface) 28E connected to a bus 28F.

[0020] The ECU 28 controls the engine 12, the generator 18, the motor 20, the inverter 24, and the battery 26. For example, the ECU 28 controls the operation of the engine 12 by controlling the accelerator opening, the fuel injection amount, etc., and controls the power generation or operation of the generator 18 and the motor 20. Furthermore, during the charge restriction and while the hybrid vehicle 10 is rolling downhill, the ECU 28 controls the consumption (discharge) of the electric power generated by the motor 20 by the generator and the engine, with the aim of suppressing the vehicle speed during the rolldown and ensuring motor output torque for climbing a slope.

[0021] Incidentally, a known example of control for the hybrid vehicle 10 is the THS (TOYOTA Hybrid System) control. In the THS control, when the vehicle is rolling downhill, the engine is motored in a fuel cut state, and the engine power loss is utilized to consume the power generated by the motor with a generator, thereby outputting motor torque for climbing a slope.

[0022] In order to ensure hill-climbing performance even under conditions of steep slope gradients, it is necessary to increase the power consumption of the generator 18 by motoring the engine 12 at high revolutions to increase the engine power loss.

[0023] However, engine noise generated by rotating the engine 12 at high speed may cause discomfort or anxiety to the driver.

[0024] Therefore, in this embodiment, the ECU 28 operates the generator 18 to motor the engine 12 during charging control and while the hybrid vehicle 10 is rolling downhill, thereby controlling the generator and the engine to consume (discharge) the power generated by the motor 20. Then, when the engine 12 is motoring, the decompression device 30 is controlled in coordination with the engine control to keep the exhaust valve of the engine 12 slightly open at all times. This increases the engine torque loss at the same engine speed and reduces the engine speed required to obtain the same engine power loss (power consumption by the generator), thereby reducing engine noise that makes the driver feel uncomfortable or uneasy.

[0025] Fig. 3 is a diagram showing an example of calculation results from an engine simulation, in which Fig. 3 shows the simulation results for a 2.0-liter in-line four-cylinder engine as an example.

[0026] The dotted line in Fig. 3 shows engine loss versus engine speed under conventional control with fuel cut and throttle valve fully closed, while the solid line in Fig. 3 shows engine loss versus engine speed under this embodiment, which, in addition to conventional control, keeps the exhaust valve slightly open at all times.

[0027] As shown in Fig. 3, by constantly slightly opening the exhaust valve in addition to the conventional control of cutting fuel and fully closing the throttle valve, it is possible to increase the engine power loss by 2.3 kW, from 5.4 kW to 7.7 kW, when the engine speed is 2000 rpm. With this increase in power loss, to obtain 5 kW of engine power loss, the motoring speed can be increased from 2000 rpm (conventional control) to 1500 rpm, making it possible to reduce the rotational speed by 500 rpm.

[0028] FIG. 4 is a diagram showing an example of the vehicle speed, accelerator opening, motor torque, engine torque, engine rotation speed, and generator torque.

[0029] In this embodiment, when anti-skid control is initiated, the ECU 28 controls the engine 12 to fully close the accelerator opening and cut off fuel. Also, the actuator of the decompression device 30 is driven to keep the exhaust valve of the engine 12 from being fully closed, and the generator 18 is driven to generate generator torque and motor the engine 12, as shown in FIG.

[0030] The engine 12 is motored by the generator 18. At this time, the engine torque loss increases compared to the conventional control shown by the dotted line in Fig. 4 by controlling the decompression device 30 so that the exhaust valve is not completely closed. As a result, the engine speed required to obtain the same engine torque loss (power consumption of the generator) can be reduced compared to the conventional control shown by the dotted line in Fig. 4, thereby reducing engine noise that makes the driver feel uncomfortable or uneasy.

[0031] In the above embodiment, the hybrid vehicle 10 may be any of a parallel hybrid capable of transmitting both engine driving force and motor driving force, a series hybrid in which all engine output is converted into electrical energy and only motor driving force is obtained, and a parallel-series hybrid that combines the features of both.

[0032] Furthermore, the processing performed by the ECU 28 in each of the above embodiments may be software processing performed by executing a program, or may be processing performed by hardware such as a GPU (Graphics Processing Unit), ASIC (Application Specific Integrated Circuit), or FPGA (Field-Programmable Gate Array). Alternatively, the processing may be a combination of both software and hardware. Furthermore, if the processing is software processing, the program may be stored in various storage media and distributed.

[0033] Furthermore, the present invention is not limited to the above, and it goes without saying that various modifications can be made without departing from the spirit of the present invention. [Explanation of symbols]

[0034] 10 Hybrid vehicles 12 Engine 18 Generator 20 Motor (driver) 26 Battery 28 ECU (control unit) 30 Decompression device

Claims

[Claim 1] The hybrid vehicle is equipped with an engine, a generator that generates electric power by driving the engine and is capable of motoring the engine, a battery that stores the electric power generated by the generator, a drive machine that is driven by the electric power stored in the battery, and a decompression device that prevents an exhaust valve of the engine from being completely closed, and the hybrid vehicle is equipped with a control unit that controls the engine, the generator, the drive machine, and the decompression device, A hybrid vehicle control device wherein the control unit motors the engine using the generator while charging is limited and the vehicle is rolling downhill, and controls the exhaust valve to a state where it is not completely closed using the decompression device.

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