Vehicle control method and control device

Abstract

In the present invention, when the main switch of a vehicle turns off (t3), an ECU (11) enters a post-run state and executes predetermined post-processing which includes an opening control of a high-power relay (21). If the main switch turns on again before the high-power relay (21) enters an open state (t11), the ECU (11) restarts. At this time, a control parameter related to the control of an internal combustion engine (2) or a self-diagnosis function is reset without resetting a high-power relay-related parameter. The high-power relay (21) which was in a closed state at the point in time (t11) continues to be in a closed state. A sudden interruption in the high-power relay (21) accompanying a parameter reset is avoided.

Description

Vehicle control method and control device

[0001] The present invention relates to the control of a vehicle, such as a series hybrid vehicle or an electric vehicle, that has, as its electrical system, a high-voltage system for vehicle running and a low-voltage system for controlling each part of the vehicle.

[0002] For example, in a series hybrid vehicle, power temporarily stored in a high-voltage battery is supplied to a traction motor / generator via an inverter circuit to drive the vehicle. The high-voltage system of such a vehicle includes a high-voltage relay for keeping the high-voltage battery disconnected while the vehicle is stopped after a trip. For example, a high-voltage relay including a pre-charge relay is provided between the high-voltage battery and the inverter circuit. The opening and closing of this high-voltage relay is controlled according to a predetermined sequence by a vehicle controller including a CPU.

[0003] On the other hand, the internal combustion engine in a series hybrid vehicle is controlled by the same controller as one of the low-voltage electronic devices.

[0004] The vehicle controller, which controls both the opening and closing of such high-voltage relays and the low-voltage electronic devices, is powered off when the vehicle is stopped and is activated when the vehicle's main switch (also called an ignition switch) is turned on. When the vehicle's main switch is turned on, a soft reset of the controller is always performed. This soft reset initializes and resets various parameters of the controller, including high-voltage relay-related control parameters associated with the high-voltage relays. When the vehicle's main switch is turned on, the high-voltage relays that are in the open state while the vehicle is stopped are controlled to the closed state according to a predetermined sequence as the related control parameters are reset.

[0005] When the trip ends and the driver turns off the main switch, the controller performs post-processing, including maintaining the high-voltage relay in a closed state according to a predetermined sequence and then opening it, before turning off. Post-processing generally takes several seconds to several tens of seconds, during which the controller remains in the on state.

[0006] After the driver stops the vehicle and turns off the main switch, the driver may turn the main switch on again before the post-processing is completed, particularly before the high-voltage relay has been opened. In this case, the high-voltage relay, which was in a closed state (i.e., conductive state), is shut off as a result of a soft reset of the controller. In other words, the relay is forcibly opened once, and then closed again according to a predetermined sequence.

[0007] Such a soft reset of the controller suddenly switches the high-voltage relay off from a conductive state, which may result in damage to the high-voltage relay.

[0008] Patent Document 1 discloses adding an SMR control signal holding unit to a control circuit of a high-power system, which is configured to hold the conductive state of a system main relay (SMR) in a high-power system until a cut-off time based on a built-in timer has elapsed when an OFF signal is output from a control ECU to the system main relay. However, this configuration not only requires a separate SMR control signal holding unit, but also requires a command to release the holding function when it is actually necessary to cut off the system main relay, which is undesirable.

[0009] JP 2008-206288 A

[0010] This invention is a vehicle control method in which a controller that controls low-voltage electronic devices in the vehicle controls the opening and closing of a high-voltage relay that is interposed in a high-voltage system that supplies power to the vehicle's driving motor, and when the vehicle's main switch is turned on and the controller is started, a soft reset of the controller is performed to reset control parameters, and when the main switch is turned off, post-processing is performed including maintaining the high-voltage relay in a closed state, and then the controller is turned off.After the main switch is turned off, if the main switch is turned on again before the post-processing is completed, a soft reset of the controller is performed without shutting off the high-voltage relay.

[0011] This prevents the high-voltage relay in a conducting state from suddenly being cut off, and prevents damage to the high-voltage relay.

[0012] 1 is a diagram illustrating the configuration of a series hybrid vehicle; 2 is a diagram illustrating the configuration of a controller of an embodiment; 3 is a flowchart showing the processing flow during a soft reset; 4 is a time chart showing the operation when the main switch is turned off, the power supply to the controller is turned off, and then the main switch is turned on again; 5 is a time chart showing the operation when the main switch is turned off, and then the main switch is turned on again before the power supply to the controller is turned off.

[0013] An embodiment in which the present invention is applied to a series hybrid vehicle will be described in detail below. Fig. 1 is an explanatory diagram showing the basic configuration of a series hybrid vehicle. As shown in the figure, the series hybrid vehicle is configured to include a power-generating motor-generator 1 that operates primarily as a generator, an internal combustion engine 2 that is used as a power-generating internal combustion engine to drive the power-generating motor-generator 1 in response to power demands, a traction motor-generator 4 that operates primarily as a motor to drive drive wheels 3, and a high-voltage battery 5 that stores the generated power.

[0014] The electric power obtained by the internal combustion engine 2 driving the power generation motor generator 1 is stored in a high-voltage battery 5 via an inverter circuit (not shown). The driving motor generator 4 is controlled and driven using the electric power of the high-voltage battery 5. The electric power generated by the driving motor generator 4 during regeneration is stored in the high-voltage battery 5 via an inverter circuit (not shown).

[0015] The operation of the motor generators 1 and 4, the charging and discharging of the high-voltage battery 5, and the operation of the internal combustion engine 2 are controlled by a controller 6. The controller 6 controls both the opening and closing of high-voltage relays (described later) provided in the high-voltage system, and the low-voltage electronic devices in the vehicle, including the control of the internal combustion engine 2. The controller 6 also has a self-diagnosis function (OBD) required by the laws and regulations of each country for compliance with exhaust regulations and safe driving.

[0016] FIG. 2 shows the basic circuit configuration of the controller 6. The control unit (ECU) 11, which constitutes the main part of the controller 6, includes a CPU 12 and operates using an auxiliary battery 13, which serves as a low-voltage power source and has a voltage of approximately 12 V to 48 V. A signal from the vehicle's main switch (ignition switch) is input to the control unit 11 via an ignition relay 15 in an underhood switching module (USM) 14. The ignition relay 15 is opened and closed by a body control module (BCM) 16, which controls the functions of all electrical components of the vehicle (e.g., air conditioning, lights, doors, power windows, mirrors, wipers, etc.). The ECU 11 and the BCM 16 are connected via a CAN communication network, and more specifically, they communicate with each other via a central gateway (CGW) 17, which relays CAN signals.

[0017] In one embodiment, the vehicle is equipped with a smart entry system, and a lock / unlock signal from a smart key (not shown) is input via the BCM 16. In one embodiment, before the driver turns on the main switch, the ECU 11 is started based on the input of an unlock signal from the smart entry system.

[0018] The battery pack, which is a high-voltage battery of about 300 to 400 V, for example, made up of lithium-ion batteries, that constitutes the high-power system, contains a lithium-ion battery controller (LBC) 18 that controls the current value according to the SOC, temperature, etc., and a battery junction box (BJB) 19 located at the input / output section of the battery pack. The BJB 19 also contains a high-power relay 21 that opens and closes the connection between the high-voltage battery 20 and an inverter circuit (not shown). While the high-voltage battery 20 is shown schematically within the BJB 19 in the figure, the battery module for the high-voltage battery 20 is actually located outside the BJB 19.

[0019] Although not specifically distinguished, the high-voltage relay 21 is configured by combining three relays: a positive main relay 21a that opens and closes the positive (+) side of the high-voltage battery 20; a negative main relay 21b that opens and closes the ground or negative (-) side; and a precharge relay 21c for precharging during close control. Strictly speaking, the "high-voltage relay" in the claims corresponds to both the positive main relay 21a and the negative main relay 21b. Therefore, the following explanations of "open" and "closed" refer to the open and closed states of the positive main relay 21a and the negative main relay 21b.

[0020] The high-voltage relays 21 (relays 21a, 21b, and 21c) are each opened and closed via an interface (I / F) 22 within the ECU 11. Specifically, the relays 21a, 21b, and 21c are all normally open relays, and are maintained in a closed state while current is flowing through the coils via the I / F 22. Therefore, when the vehicle is completely stopped and left unattended, the relays 21a, 21b, and 21c are all in an open state.

[0021] Next, the operation of the above embodiment will be described with reference to Figures 4 and 5. These time charts compare (a) the state of the vehicle, (b) the state of the ECU 11, (c) the driving cycle (DC) of the self-diagnosis function (OBD), and (d) the state of the high-voltage relay 21 (particularly, the relays 21a and 21b).

[0022] First, the timing chart of Fig. 4 will be described. In the initial state of Fig. 4, the vehicle is stopped and locked, the power supply to the ECU 11 is off, and the high-voltage relay 21 is open.

[0023] Time t1 is the timing when the driver unlocks the vehicle. This unlocking turns on the power to the ECU 11, which enters a startup state. At this time, a soft reset of the ECU 11 is performed, and various control parameters, including high-voltage relay-related parameters and parameters related to the control of the internal combustion engine 2, are initialized and reset. That is, the control parameters are cleared to 0, and then necessary initial values ​​are set. The ECU 11 then goes through internal error checks and enters a wake-up state. As the high-voltage relay-related parameters are reset, the high-voltage relay 21 enters a closed state according to a predetermined sequence. Various parameters related to the self-diagnosis function are also reset at this time. Accordingly, the value indicating the driving cycle (DC) of the self-diagnosis function becomes the next incremented value. Each driving cycle (DC) represents one trip.

[0024] At time t2, the driver turns on the main switch of the vehicle. When the main switch is turned on, the ECU 11 enters the run state. The vehicle travels in response to the driver's accelerator operation.

[0025] Time t3 is the timing when the vehicle stops traveling and the driver turns off the vehicle's main switch. This main switch-off puts the ECU 11 into a post-run state and executes predetermined post-processing, including maintaining the high-voltage relay 21 in a closed state and subsequently opening it. As one example of the post-processing, for example, the radiator fan of the internal combustion engine 2 continues to operate. At time t4, the high-voltage relay 21 opens according to a predetermined sequence. Then, at time t5, the power to the ECU 11 is turned off. The post-processing (maintaining the high-voltage relay 21 in a closed state) takes, for example, several tens of seconds. After the power to the ECU 11 is turned off, the vehicle as a whole enters a standby state, waiting for the smart key to be locked or unlocked or the main switch to be turned on or off, thanks to functions such as the BCM 16.

[0026] In the example of FIG. 4 , after the ECU 11 is powered off, the driver turns on the vehicle's main switch again at time t6 before the vehicle is locked. This powers on the ECU 11 and puts it into a startup state. At this time, a soft reset of the ECU 11 is performed, and various control parameters, including high-voltage relay-related parameters and parameters related to the control of the internal combustion engine 2, are initialized and reset. The ECU 11 then goes through an internal error check and enters a run state. The vehicle then travels again in response to the driver's accelerator operation. Note that, as described above, when the ECU 11 is powered off and activated by an unlock operation, it enters a wake-up state and waits for the main switch to be turned on. However, when the ECU 11 is powered off and activated by the main switch being turned on, it enters a run state without going through the wake-up state.

[0027] With the resetting of the high-voltage relay-related parameters at time t6, the high-voltage relay 21 closes according to a predetermined sequence. Furthermore, with the resetting of the self-diagnostic function parameters, the value indicating the operating cycle (DC) is incremented. In other words, the self-diagnostic function distinguishes between trips between times t2 and t3 and trips occurring after time t6 as different trips. This is also a legal requirement regarding the self-diagnostic function.

[0028] Next, an example will be described with reference to Fig. 5. Fig. 5 shows the operation when the driver turns on the main switch of the vehicle before the high-voltage relay 21 is opened while the ECU 11 is in the post-run state.

[0029] The explanation for times t1, t2, and t3 is the same as in the case of Fig. 4. When the driver turns off the vehicle's main switch at time t3, the ECU 11 enters the post-run state and executes predetermined post-processing. Here, in the example of Fig. 5, the driver turns on the vehicle's main switch again at time t11 before the high-voltage relay 21 is opened according to a predetermined sequence during post-processing.

[0030] When the main switch is turned on, a soft reset of the ECU 11 is executed. Because the ECU 11 was in the post-run state at time t11, the soft reset temporarily turns off the power to the ECU 11 and restarts it. The ECU 11 then goes through the startup state and then into the run state. The soft reset of the ECU 11 also resets various parameters related to the self-diagnosis function, thereby incrementing a value indicating the driving cycle (DC) of the self-diagnosis function. In other words, to comply with legal requirements, the self-diagnosis function distinguishes between trips between times t2 and t3 and trips after time t11 as different trips. Parameters related to the control of the internal combustion engine 2 are also initialized and reset to predetermined values.

[0031] On the other hand, when the main switch is turned on while the ECU 11 is in the post-run state, the high-power relay-related parameters are not reset. In other words, resetting of the high-power relay-related parameters is prohibited. Therefore, the high-power relay 21 that was in the closed state at time t11 remains in the closed state. In other words, a sudden shutoff of the high-power relay 21 due to a parameter reset is avoided.

[0032] The characteristics shown by the phantom line in column (d) show a comparative example in which the resetting of the high-voltage relay-related parameters is permitted when the main switch is turned on while the ECU 11 is in the post-run state. In this case, the high-voltage relay-related parameters are initialized at time t11, temporarily stopping the current flow to the coil of the high-voltage relay 21. The high-voltage relay-related parameters are then reset, causing the high-voltage relay 21 to close in accordance with a predetermined sequence. Therefore, at time t11, the high-voltage relay 21 is suddenly disconnected without following the predetermined sequence, which could result in damage to the high-voltage relay 21.

[0033] In this manner, in the above embodiment, if the vehicle's main switch is turned off (time t3) and then turned on again (time 11) before the post-processing is completed, a soft reset of the ECU 11 is executed without turning off the high-voltage relay 21. Therefore, damage caused by a sudden turning off of the high-voltage relay 21 is suppressed.

[0034] 3 is a flowchart showing the flow of a soft reset process executed when the main switch is turned on while the ECU 11 is in the post-run state. First, in step 1, it is determined whether each control parameter is a high-voltage relay-related parameter. If the parameter is not a high-voltage relay-related parameter, the process proceeds to step 2, where the control parameter is reset. For example, in step 2, control parameters related to control of the internal combustion engine 2 are reset. Furthermore, in step 3, control parameters related to the self-diagnosis function are reset. As a result of this reset, the value indicating the driving cycle (DC) becomes the following value.

[0035] For the high-voltage relay-related parameters, the resetting exemplified in steps 2 and 3 (clearing the control parameters and setting the initial values) is skipped.

[0036] Then, in step 4, control is started in a predetermined calculation cycle, so that control is started while maintaining the previous values ​​of the high-voltage relay-related parameters.

[0037] Thus, in one embodiment, when the main switch is turned on while the ECU 11 is in the post-run state, the high-voltage relay-related parameters are not reset, but the control parameters of at least some of the low-voltage electronic devices that do not affect the opening and closing of the high-voltage relay are reset.

[0038] The above has been described regarding the soft reset that is executed when the main switch is turned on while the ECU 11 is in the post-run state, but a soft reset may also be requested based on the detection of an error during operation of the ECU 11. In a preferred embodiment, even in such a case, the soft reset of the ECU 11 is performed without resetting the high-power relay-related parameters. In other words, the sudden interruption of the high-power relay 21 that would otherwise occur when the high-power relay-related parameters are reset is avoided.

[0039] The above describes one embodiment in which the present invention is applied to a series hybrid vehicle. However, the present invention is not limited to series hybrid vehicles and can be similarly applied to other types of hybrid vehicles and battery-electric vehicles.

Claims

The controller that controls the low-voltage electronic devices in the vehicle controls the opening and closing of the high-voltage relays that are interposed in the high-voltage system that supplies power to the vehicle's driving motor, When the main switch of the vehicle is turned on and the controller is started, a soft reset of the controller is performed to reset the control parameters; When the main switch is turned off, after performing post-processing including maintaining the high-voltage relay in a closed state, the controller is turned off. A vehicle control method comprising: A vehicle control method in which, if the main switch is turned on again after the main switch is turned off and before the post-processing is completed, a soft reset of the controller is performed without shutting off the high-voltage relay. moreover, When a soft reset is requested based on the detection of an error during operation of the controller, A soft reset of the controller is performed without interrupting the high-voltage relay. The vehicle control method according to claim 1 . 　 the vehicle is a hybrid vehicle having an internal combustion engine, and the controller controls the internal combustion engine as the low-voltage electronic device; If the main switch is turned on again after the main switch is turned off and before the post-processing is completed, the control parameters related to the internal combustion engine are reset without resetting the control parameters related to the high-voltage relay, which involves shutting off the high-voltage relay. The vehicle control method according to claim 1 . 　 the controller has a self-diagnosis function in relation to the control of the low-voltage electronic device, If the main switch is turned on again after the main switch is turned off and before the post-processing is completed, the control parameters related to the self-diagnosis function are reset without resetting the control parameters related to the high-voltage relay, which involves shutting off the high-voltage relay. The vehicle control method according to claim 1 . 　 When the main switch is turned on again after the main switch is turned off and before the post-processing is completed, resetting of control parameters related to the high-voltage relay, which involves turning off the high-voltage relay, is not performed, but control parameters of at least some of the low-voltage electronic devices that do not affect the opening and closing of the high-voltage relay are reset. The vehicle control method according to claim 1 . 　 When the main switch is turned off and the main switch is turned on again to start up the controller during the period from when the main switch is turned off until the post-processing is completed, the control parameters are individually determined to be control parameters related to a high-voltage relay that involves turning off the high-voltage relay or control parameters of a low-voltage electronic device that does not affect the opening and closing of the high-voltage relay, and if they are control parameters of a low-voltage electronic device, the control parameters are reset. The vehicle control method according to claim 1 . 　 a vehicle having a low-voltage electronic device; a high-voltage relay interposed in a high-voltage system that supplies power to a vehicle's driving motor; a controller that controls the low-voltage electronic devices and the high-voltage relay; a main switch operated by the driver; Including, When the main switch is turned on and the controller is started, a soft reset of the controller is performed to reset the control parameters; When the main switch is turned off, after performing post-processing including maintaining the high-voltage relay in a closed state, the controller is turned off. In a vehicle control device, A vehicle control device that performs a soft reset of the controller without shutting off the high-voltage relay when the main switch is turned on again after the main switch is turned off and before the post-processing is completed.

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