Control device of hybrid vehicle

Abstract

To prevent a request output of an engine from becoming excessive, when the engine is in a cold state.SOLUTION: A control device of a hybrid vehicle including a battery, a motor, and an engine as driving sources performs a start request of the engine, during traveling of the hybrid vehicle by the motor, in a case in which an output restriction of the battery is estimated, and the travel load of the hybrid vehicle is a low travel load equal to or less than a predetermined value.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] The following Patent Document 1 discloses a technology in which, in a hybrid vehicle, when it is determined that the battery is in a low output state, the engine is started in advance, thereby suppressing a decrease in the driving force of the drive motor due to engine start, even when the battery's charging and discharging power is limited. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-059093 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, it has been known that in hybrid vehicles that use lithium ion batteries as their batteries, when a large current continues to flow through the battery, a large amount of lithium ions accumulate on the surface of the active material of the positive electrode inside the battery, causing voltage resistance (i.e., the battery becomes polarized).

[0005] Therefore, in such hybrid vehicles, when it is estimated that battery polarization has occurred, a method can be considered in which the battery output is limited and an engine start request is made to suppress power consumption of the battery.

[0006] However, in such a hybrid vehicle, if a request to start the engine is made in a cold state, there is a risk that PN emissions from the engine will increase if the requested engine output becomes excessive. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, a control device for a hybrid vehicle according to one embodiment is a control device for a hybrid vehicle that has a battery and a motor and engine as drive sources, and when the battery output limit is estimated while the hybrid vehicle is running on the motor, a request is made to start the engine when the running load of the hybrid vehicle is a low running load that is equal to or less than a predetermined value. [Effects of the Invention]

[0008] According to the control device for a hybrid vehicle according to one embodiment, it is possible to prevent the required output of the engine from becoming excessive when the engine is in a cold state. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing a configuration of a hybrid vehicle according to an embodiment; [Figure 2] 1 is a flowchart showing an example of a procedure of processing by an ENGECU included in a hybrid vehicle according to an embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] (Configuration of Hybrid Vehicle 1) Fig. 1 is a diagram showing the configuration of a hybrid vehicle 1 according to one embodiment. The hybrid vehicle 1 shown in Fig. 1 includes an engine 10, a first motor generator 52, and a second motor generator 54 as drive sources for driving the hybrid vehicle 1.

[0012] As shown in FIG. 1, engine 10 has four cylinders #1 to #4. A throttle valve 14 is provided in an intake passage 12 of engine 10. Air drawn into intake passage 12 flows into each combustion chamber 18 of four cylinders #1 to #4 as intake valves 16 open. Fuel is injected into combustion chamber 18 from a direct injection valve 22. The air-fuel mixture in combustion chamber 18 is combusted in response to spark discharge from a spark plug 24. The combustion energy generated at this time is converted into rotational energy of a crankshaft 26.

[0013] When an exhaust valve 28 opens, exhaust gas generated as a result of combustion in the combustion chamber 18 is discharged into an exhaust passage 30. A three-way catalyst 32 having an oxygen storage capacity and a GPF (gasoline particulate filter) 34 are provided in the exhaust passage 30. In this embodiment, an example of the GPF 34 is a filter that collects PM and supports a three-way catalyst.

[0014] The crankshaft 26 is mechanically connected to a carrier C of a planetary gear mechanism 50 that constitutes a power split device. A rotating shaft 52a of a first motor generator 52 is mechanically connected to a sun gear S of the planetary gear mechanism 50. Furthermore, a rotating shaft 54a of a second motor generator 54 and a drive shaft 61 for transmitting driving force to drive wheels 60 are mechanically connected to a ring gear R of the planetary gear mechanism 50.

[0015] The first inverter 56 and the second inverter 58 convert the DC voltage output from the battery 59 into an AC voltage. The first inverter 56 applies the AC voltage to the first motor generator 52 (an example of a "motor"). The second inverter 58 applies the AC voltage to the second motor generator 54 (an example of a "motor"). In this embodiment, a lithium-ion secondary battery is used as the battery 59.

[0016] The ENGECU 70 controls the engine 10. For example, the ENGECU 70 controls the throttle valve 14, the in-cylinder injection valve 22, the spark plug 24, and the like in order to control the torque of the engine 10, the ratio of exhaust components, and the like.

[0017] In order to control the engine 10, the ENGECU 70 refers to the intake air amount Ga detected by the air flow meter 80, the output signal Scr of the crank angle sensor 82, the upstream detected value Afu which is the detected value of the upstream air-fuel ratio sensor 84 provided upstream of the three-way catalyst 32, the downstream detected value Afd which is the detected value of the downstream air-fuel ratio sensor 86 provided downstream of the three-way catalyst 32, the pressure Pex of the exhaust gas flowing into the GPF 34 detected by the exhaust pressure sensor 88, and the water temperature THW detected by the water temperature sensor 90.

[0018] The ENGECU 70 includes a CPU 72, a ROM 74, and a peripheral circuit 76, which are communicatively connected by a communication line 78. The peripheral circuit 76 includes a circuit that generates a clock signal that regulates internal operation, a power supply circuit, a reset circuit, etc. The ENGECU 70 achieves control of the engine 10 by the CPU 72 executing a program stored in the ROM 74. The ENGECU 70 is further communicatively connected to the MGECU 100 and the HVECU 120.

[0019] The MGECU 100 controls the rotation speed of the first motor generator 52 by controlling the first inverter 56. The MGECU 100 also controls the rotation speed of the second motor generator 54 by controlling the second inverter 58. To control the first inverter 56 and the second inverter 58, the MGECU 100 refers to an output signal Sm1 of a first rotation angle sensor 110 that detects the rotation angle of the first motor generator 52 and an output signal Sm2 of a second rotation angle sensor 112 that detects the rotation angle of the second motor generator 54.

[0020] The MGECU 100 includes a CPU 102, a ROM 104, and a peripheral circuit 106, which are communicatively connected by a communication line 108. The MGECU 100 realizes control of the first motor generator 52 and the second motor generator 54 by the CPU 102 executing a program stored in the ROM 104.

[0021] The HVECU 120 controls a hybrid system including the engine 10, the first motor generator 52, and the second motor generator 54 via the ENGECU 70 and the MGECU 100. To control the hybrid system, the HVECU 120 refers to the accelerator operation amount ACCP detected by the accelerator opening sensor 130 and the output signal Sp of the output side rotation angle sensor 132 that detects the rotation angle of the ring gear R.

[0022] The HVECU 120 includes a CPU 122, a ROM 124, and a peripheral circuit 126, which are communicatively connected by a communication line 128. The HVECU 120 controls the hybrid system by the CPU 122 executing a program stored in the ROM 124.

[0023] (An example of processing procedures using ENGECU70) FIG. 2 is a flowchart showing an example of a procedure of processing by the ENGECU 70 provided in the hybrid vehicle 1 according to one embodiment.

[0024] In this embodiment, the ENGECU 70 serves as the "towed vehicle control device" and executes the series of processes shown in Fig. 2. However, this is not limiting, and another device provided in the hybrid vehicle 1 may also serve as the "towed vehicle control device" and execute the series of processes shown in Fig. 2.

[0025] Furthermore, the ENGECU 70 executes the process shown in FIG. 2 when the hybrid vehicle 1 is running using the motors (the first motor generator 52 and the second motor generator 54).

[0026] First, the ENGECU 70 determines whether or not there is a polarization occurrence estimation command for the battery 59 (step S201). Here, the polarization occurrence estimation command for the battery 59 is generated when it is estimated that polarization has occurred in the battery 59 and that lithium ions have accumulated on the surface of the positive electrode active material in the battery 59, causing voltage resistance. For example, the ENGECU 70 monitors the voltage difference between the cells of the battery 59, and determines that there is a polarization occurrence estimation command for the battery 59 when the voltage difference between the cells of the battery 59 is equal to or greater than a predetermined threshold value.

[0027] In step S201, if it is determined that there is no polarization occurrence estimation instruction (step S201: NO), the ENGECU 70 does not issue a start request for the engine 10 (step S205), and ends the series of processes shown in FIG.

[0028] If it is determined in step S201 that a polarization occurrence estimation command has been issued (step S201: YES), the ENGECU 70 determines whether the running load of the hybrid vehicle 1 is a low running load within a predetermined value (step S202). Here, the ENGECU 70 comprehensively determines and quantifies the running load of the hybrid vehicle 1 based on, for example, the vehicle speed, engine speed, accelerator opening, etc. The predetermined value is an appropriate running load value that does not cause the required output of the engine 10 to become excessive, and is determined in advance by simulation or the like and stored in advance in a memory or the like provided in the ENGECU 70.

[0029] In step S202, if it is determined that the running load of the hybrid vehicle 1 is not a low running load within the predetermined value (step S202: NO), the ENGECU 70 limits the output of the engine 10 (step S206), and proceeds to step S204.

[0030] In step S202, if it is determined that the running load of the hybrid vehicle 1 is a low running load within a predetermined value (step S202: YES), the ENGECU 70 issues a request to start the engine 10 (step S203), and the process proceeds to step S204.

[0031] In step S204, the ENGECU 70 determines whether the water temperature of the engine 10 (i.e., the water temperature THW detected by the water temperature sensor 90) is within a predetermined value (step S204). Here, the predetermined value is an appropriate water temperature value that does not increase the PN output from the engine 10, and is obtained in advance by simulation or the like and stored in advance in a memory or the like provided in the ENGECU 70.

[0032] In step S204, if it is determined that the water temperature of the engine 10 is not within the predetermined value (step S204: NO), the ENGINE CU 70 returns the process to step S201.

[0033] In step S204, if it is determined that the water temperature of the engine 10 is within the predetermined value (step S204: YES), the ENGINE CU 70 ends the series of processes shown in FIG.

[0034] As described above, the ENGECU 70 in one embodiment is a control device for a hybrid vehicle 1 that has a battery 59, motors (first motor generator 52 and second motor generator 54) as drive sources, and an engine 10, and when the hybrid vehicle 1 is running using the motor, if an output limit of the battery 59 is estimated (in this embodiment, if polarization of the battery 59 is estimated), and if the running load of the hybrid vehicle 1 is a low running load that is below a predetermined value, a request to start the engine 10 can be made.

[0035] As a result, the ENGECU 70 in one embodiment can start the engine 10 and warm up the water temperature of the engine 10 when the running load of the hybrid vehicle 1 is low, that is, below a predetermined value, thereby preventing the required output of the engine 10 from becoming excessive when the engine 10 is in a cold state.

[0036] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims. [Explanation of symbols]

[0037] 1 Hybrid vehicle 10 Engine 52 First motor generator (motor) 54 Second motor generator (motor) 59 Battery 70 ENGECU (Hybrid vehicle control unit)

Claims

[Claim 1] A control device for a hybrid vehicle having a battery and a motor and an engine as drive sources, When the hybrid vehicle is traveling by the motor, if an output limit of the battery is estimated, a request to start the engine is made when the traveling load of the hybrid vehicle is a low traveling load equal to or less than a predetermined value. A control device for a hybrid vehicle.

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