Control device of hybrid vehicle

Abstract

To provide a control device of a hybrid vehicle which can inhibit an engine from starting when a vehicle is stopped.SOLUTION: A hybrid vehicle 1 includes a motor 3 and an engine 2 as power sources. A control device 5 of the hybrid vehicle 1 performs control so as to reduce a threshold value of an accelerator opening at the start of the engine 2 as an amount of change of a charging state of a battery 4 for supplying electric power to the motor 3 increases.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Patent Document 1 describes an engine start control for a hybrid vehicle powered by a motor and an engine, in which when the required output of the vehicle according to the amount of depression of the accelerator pedal exceeds a predetermined first threshold while the engine is stopped, a second threshold greater than the first threshold is set, and the engine is started when the required output exceeds the second threshold, thereby preventing unnecessary engine starts in the hybrid vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-151894 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the conventional engine start control method for a hybrid vehicle described in Patent Document 1 and the like leaves room for improvement in terms of suppressing engine start while the vehicle is stopped.

[0005] An object of the present disclosure is to provide a control device for a hybrid vehicle that can prevent the engine from starting while the vehicle is stopped. [Means for solving the problem]

[0006] A control device for a hybrid vehicle according to one aspect of an embodiment of the present invention is a control device for a hybrid vehicle powered by a motor and an engine, and the greater the change in the state of charge of the battery that supplies power to the motor, the smaller the accelerator opening threshold for starting the engine. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide a control device for a hybrid vehicle that can prevent the engine from starting while the vehicle is stopped. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of a hybrid vehicle according to an embodiment; [Figure 2] FIG. 2 is a diagram illustrating engine start control performed by the control device according to the present embodiment. [Figure 3] FIG. 10 is a diagram illustrating engine start control by a control device according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the accompanying drawings. To facilitate understanding of the description, the same components in the drawings will be denoted by the same reference numerals as much as possible, and duplicated descriptions will be omitted.

[0010] 1 is a block diagram showing a schematic configuration of a hybrid vehicle 1 according to an embodiment. As shown in FIG. 1, the hybrid vehicle 1 includes an engine 2, a motor 3, a battery 4, and a control device 5.

[0011] The engine 2 and the motor 3 are the power sources of the hybrid vehicle 1. The battery 4 supplies power to the motor 3. The control device 5 controls the operation of each element mounted on the vehicle, such as the engine 2, the motor 3, and the battery 4. The control device 5 also monitors the state of charge (SOC) of the battery 4.

[0012] Fig. 2 is a diagram illustrating the start control of the engine 2 by the control device 5 according to this embodiment. The horizontal axis of Fig. 2 represents the SOC of the battery 4. The vertical axis of Fig. 2 represents the accelerator opening degree at which the engine 2 is started. In other words, the graph shown in Fig. 2 shows the characteristics of the accelerator opening degree at which the engine 2 is started, which is adjusted according to the SOC.

[0013] With this characteristic, when the SOC is equal to or greater than a predetermined value A, the accelerator opening degree for starting the engine 2 is constant. On the other hand, when the SOC is less than the predetermined value A, i.e., when the SOC is relatively low, the accelerator opening degree for starting the engine 2 is set to decrease as the SOC decreases (approaching 0%). The accelerator opening degree decreases linearly, for example, from a set value at the predetermined value A in the direction in which the SOC decreases (toward the left on the horizontal axis in FIG. 2). With this characteristic of the accelerator opening degree, the lower the SOC, the lower the accelerator opening degree for starting the engine 2, thereby reducing the risk of the engine 2 starting while the vehicle is stopped. This eliminates any discomfort felt by the driver.

[0014] In particular, in this embodiment, the control device 5 performs control such that the greater the amount of change in SOC, the smaller the accelerator opening threshold for starting the engine 2. In other words, the engine is started even if the accelerator pedal depression amount is small.

[0015] This control can be expressed in the graph shown in FIG. 2 as a characteristic in which the amount of change in accelerator opening according to SOC (i.e., the slope of the graph) increases relatively as the amount of SOC change increases in the range in which the SOC is less than a predetermined value A.

[0016] This control allows the engine 2 to be started early when there is a high possibility that the SOC will decrease, thereby enabling the control device 5 of the hybrid vehicle 1 of this embodiment to prevent the engine 2 from being started while the vehicle is stopped.

[0017] The greater the change in SOC, the faster the SOC decreases, increasing the risk of the engine 2 starting when the vehicle is stopped. By enabling the engine 2 to start with a low accelerator opening using the control of this embodiment, the risk of the engine 2 starting while the vehicle is stopped can be further reduced. This further alleviates any discomfort felt by the driver.

[0018] The control device 5 can be physically configured as a computer system or control board including a CPU (Central Processing Unit), RAM (Random Access Memory) and ROM (Read Only Memory) as main storage devices, input devices, output devices, a communication module, auxiliary storage devices such as a hard disk, etc. Each function of the control device 5 is realized by loading predetermined computer software onto hardware such as the CPU and RAM, thereby operating the communication module, input devices, and output devices under the control of the CPU and reading and writing data from and to the RAM and auxiliary storage devices. The control device 5 may also be implemented as part of an on-board ECU (Electronic Control Unit).

[0019] 3 is a diagram illustrating the start control of the engine 2 by the control device 5 according to a modified example. The outline of FIG. 3 is the same as that of FIG.

[0020] The control device 5 may be configured to perform control such that the threshold value of the accelerator opening for starting the engine is reduced as the SOC of the battery 4 is lower and as the temperature of the catalyst installed in the exhaust system of the hybrid vehicle is lower.

[0021] This control can be expressed in the graph shown in FIG. 3 as a characteristic in which the amount of change in accelerator opening according to SOC (i.e., the slope of the graph) in the range where the SOC is less than a predetermined value A becomes relatively larger as the catalyst temperature decreases.

[0022] The lower the SOC, the more likely engine 2 is started at a lower accelerator opening, reducing the risk of engine 2 starting while the vehicle is stopped. This eliminates any discomfort felt by the driver. Furthermore, as shown in Figure 3, the lower the catalyst temperature, the more likely engine 2 is started at a smaller accelerator opening, ensuring time for catalyst warm-up. This allows catalyst warm-up to be completed before the engine load increases, preventing a deterioration in emissions.

[0023] It is also possible to combine the control according to the embodiment described with reference to FIG. 2, in which the threshold value of the accelerator opening degree at the start of the engine 2 is changed depending on the SOC change amount, with the control according to the modified example described with reference to FIG. 3, in which the threshold value of the accelerator opening degree at the start of the engine 2 is changed depending on the catalyst temperature.

[0024] The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Design modifications to these specific examples made by a person skilled in the art as appropriate are also included within the scope of the present disclosure as long as they comprise the features of the present disclosure. The elements of each of the above-described specific examples, as well as their arrangement, conditions, shape, etc., are not limited to those exemplified and can be modified as appropriate. The elements of each of the above-described specific examples can be combined in various ways as appropriate, as long as no technical contradictions arise. [Explanation of symbols]

[0025] 1 Hybrid vehicle 2 engines 3 motors 4 Battery 5. Control device

Claims

[Claim 1] A control device for a hybrid vehicle powered by a motor and an engine, the greater the change in the state of charge of the battery that supplies power to the motor, the smaller the accelerator opening threshold for starting the engine. A control device for a hybrid vehicle.

Images