Controller of vehicle

Abstract

To provide a controller of a vehicle which can shorten the time to warm up a catalyzer in a case of a low vehicle speed or in a case that a requirement drive torque is low to be capable of suppressing deterioration of exhaust purification performance.SOLUTION: A vehicle 10 comprises: an engine 12 and an electric motor MG; a clutch K0 which connects / disconnects power transmission between the engine 12 and the electric motor MG; a clutch WSC which connects / disconnects power transmission between the electric motor MG and a pair of driving wheels 14; and a battery 64 which transmits / receives electric power between the battery and the electric motor MG. An electric control device 90 controls the clutch K0 to be in an engagement state while warming up a catalyzer 54 that purifies exhaust gas of the engine 12, and controls the clutch WSC to be in a slip state by slip amount SLP calculated based on a charging state value SOC of the battery 64, chargeable power Win of the battery 64, a plate temperature THplt as same as temperature of the clutch WSC, and an input shaft rotation speed Nin that is an output side rotation speed of the clutch WSC.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a control device for a vehicle that is equipped with a first clutch that connects and disconnects the power transmission between an engine and an electric motor, and a second clutch that connects and disconnects the power transmission between the electric motor and a pair of drive wheels. [Background technology]

[0002] There is known a vehicle that includes a first clutch that connects and disconnects the power transmission between an engine and an electric motor, and a second clutch that connects and disconnects the power transmission between the electric motor and a pair of drive wheels. For example, there is one described in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-106710 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the vehicle described in Patent Document 1, when both the first clutch and the second clutch are engaged, the engine speed is uniquely determined by the vehicle speed and the gear ratio of the automatic transmission. Therefore, when the vehicle speed is low or the required driving torque is low, the engine load decreases and it takes time to warm up the catalyst that purifies the engine's exhaust, resulting in a deterioration in exhaust purification performance. On the other hand, when the second clutch is released, the engine can only output power equivalent to the friction, so it also takes time to warm up the catalyst, resulting in a deterioration in exhaust purification performance.

[0005] The present invention has been made against the background of the above circumstances, and its objective is to provide a vehicle control device that can shorten the time it takes to warm up the catalyst and suppress deterioration of exhaust purification performance even when the vehicle speed is low or the required driving torque is low. [Means for solving the problem]

[0006] The gist of the present invention is a control device for a vehicle including an engine and an electric motor, a first clutch that connects and disconnects power transmission between the engine and the electric motor, a second clutch that connects and disconnects power transmission between the electric motor and a pair of drive wheels, and a battery that exchanges power with the electric motor, wherein, during warm-up of a catalyst that purifies the exhaust of the engine, the first clutch is controlled to an engaged state, and the second clutch is controlled to a slip state with an amount of slip calculated based on the state of charge value of the battery, the chargeable power of the battery, the temperature of the second clutch, and the output side rotational speed of the second clutch. Effect of the Invention

[0007] According to the vehicle control device of the present invention, during warm-up of the catalyst that purifies the exhaust gas of the engine, the first clutch is controlled to an engaged state, and the second clutch is controlled to a slip state with an amount of slip calculated based on the state of charge value of the battery, the chargeable power of the battery, the temperature of the second clutch, and the output side rotation speed of the second clutch. This reduces the time required to warm up the catalyst and suppresses deterioration of exhaust purification performance even when the vehicle speed is low or the required driving torque is low. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram of a vehicle equipped with an electronic control device according to an embodiment of the present invention, and is also a functional block diagram showing essential parts of control functions for various controls in the vehicle. [Diagram 2] 2 is an example of a flowchart illustrating a control operation of the electronic control device shown in FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that in the embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of the various parts are not necessarily drawn accurately. EXAMPLES

[0010] FIG. 1 is a schematic diagram of a vehicle 10 equipped with an electronic control device 90 according to an embodiment of the present invention, and is also a functional block diagram showing the main parts of the control functions for various controls in the vehicle 10.

[0011] The vehicle 10 includes an engine 12 and an electric motor MG, which are power sources for traveling, and a power transmission device 16 provided on a power transmission path PT between the engine 12 and a pair of drive wheels 14. The vehicle 10 also includes a hydraulic control circuit 60, an inverter 62, a battery 64, and an electronic control device 90.

[0012] The engine 12 is a well-known internal combustion engine. The engine 12 is driven to rotate by burning an air-fuel mixture, in which fuel is injected into air drawn into a combustion chamber from an intake pipe 40, and exhaust gas after combustion is discharged into an exhaust pipe 50. A catalytic converter 52 is installed in the exhaust pipe 50, which is a device that reduces harmful carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) contained in the exhaust gas by a catalyst 54.

[0013] The electric motor MG is, for example, a so-called motor generator having a function as an electric motor and a function as a generator. The clutch K0 is an engagement device capable of connecting and disconnecting the power transmission between the engine 12 and the electric motor MG, and is, for example, a wet-type multi-plate hydraulic friction engagement device. The electric motor MG is driven to rotate by the electric power stored in the battery 64, and outputs the power for running the vehicle 10. In this specification, unless otherwise specified, the terms torque, driving force, power, and force (power) are synonymous. The electric motor MG generates electric power by the power for running input from the engine 12 via the clutch K0 or the driven force input from the pair of drive wheels 14, and the generated electric power is charged to the battery 64 via the inverter 62. The battery 64 exchanges electric power with the electric motor MG.

[0014] The power transmission device 16 includes, in order from the engine 12 side, a clutch K0, an electric motor connecting shaft 32 which is a rotating shaft of the electric motor MG, a clutch WSC, an AT input shaft 34, an automatic transmission 22, etc., all of which are well known components, in a case 18 which is a non-rotating member attached to the vehicle body. The power transmission device 16 also includes an AT output shaft 36, a differential 24, and a pair of axles 38, etc., all of which are well known components. The engine 12 and the clutch K0 are connected by an engine connecting shaft 30. The clutch K0 and the clutch WSC correspond to the "first clutch" and the "second clutch" in this invention, respectively.

[0015] The operating states of the clutch K0 and the clutch WSC include a fully engaged state (= connected state), a slip state (= half-engaged state), and a released state (= disconnected state). Hereinafter, the "fully engaged state" will be simply referred to as the "engaged state". The automatic transmission 22 is a well-known automatic transmission. The automatic transmission 22 is controlled so that a desired gear ratio is formed from among different gear ratios γat. The gear ratio γat is the rotational speed ratio (= Nin / Nout) between the input shaft rotational speed Nin [rpm] and the output shaft rotational speed Nout [rpm]. The input shaft rotational speed Nin is the rotational speed of the AT input shaft 34, and the output shaft rotational speed Nout is the rotational speed of the AT output shaft 36.

[0016] The hydraulic control circuit 60 supplies the necessary hydraulic oil OIL to each part within the case 18 using the hydraulic pressure of the hydraulic oil OIL discharged from, for example, an oil pump (not shown) as a source pressure.

[0017] The vehicle 10 can select either BEV (Battery Electric Vehicle) driving or engine driving. BEV driving is driving with the clutch K0 released and the motor MG as the driving power source, and engine driving is driving with the clutch K0 engaged and at least the engine 12 as the driving power source. In engine driving, the clutch K0 is engaged and the clutch WSC is engaged or in a slip state. The required driving torque Tr_dem [Nm] required for the pair of drive wheels 14 is calculated based on, for example, the accelerator opening θacc [%] operated by the driver and the actual vehicle speed V [km / h].

[0018] The electronic control unit 90 is configured to include a so-called microcomputer including, for example, a CPU, a RAM, a ROM, an input / output interface, etc. The CPU performs signal processing according to a program stored in the ROM in advance while using the temporary storage function of the RAM, thereby executing various controls of the vehicle 10. Note that the electronic control unit 90 corresponds to the "control device" in the present invention.

[0019] Various signals (for example, engine rotational speed Ne [rpm], MG rotational speed Nmg [rpm], input shaft rotational speed Nin, output shaft rotational speed Nout corresponding to the vehicle speed V, accelerator opening θacc which is the driver's accelerator operation amount representing the magnitude of the driver's acceleration operation, battery charge / discharge current Ibat [A], battery voltage Vbat [V], battery temperature THbat [°C], plate temperature THplt [°C] which is the temperature of the friction plate of the clutch WSC, catalyst temperature THcat [°C] which is the temperature of the catalyst 54, etc.) based on the detection values by various sensors (for example, engine rotational speed sensor 70, MG rotational speed sensor 72, input shaft rotational speed sensor 74, output shaft rotational speed sensor 76, accelerator opening sensor 78, battery sensor 80, plate temperature sensor 82, catalyst temperature sensor 84, etc.) are respectively input to the electronic control unit 90. Note that the engine rotational speed Ne is the rotational speed of the engine 12, and the MG rotational speed Nmg is the rotational speed of the motor MG. The plate temperature THplt corresponds to the "temperature of the second clutch" in the present invention.

[0020] The electronic control device 90 outputs various command signals (e.g., an engine control signal Se for controlling the engine 12, a shift control signal Sat for controlling shifting of the automatic transmission 22, a K0 control signal Sk0 for controlling engagement and disengagement of the clutch K0, a WSC control signal Swsc for controlling engagement and disengagement of the clutch WSC, an MG control signal Smg for controlling the rotation of the electric motor MG via the inverter 62, etc.) to each device (e.g., the engine 12, the hydraulic control circuit 60, the inverter 62, etc.) provided in the vehicle 10. "Engagement and disengagement control" refers to control of the operating state (engaged state, slip state, released state) of the clutch K0 and the clutch WSC.

[0021] The electronic control unit 90 functionally comprises an engine control unit 90a, an MG control unit 90b, a transmission control unit 90c, a K0 control unit 90d, a WSC control unit 90e, a warm-up determination unit 90f, a data acquisition unit 90g, a slip permission determination unit 90h, a slip amount calculation unit 90i, and a loss calculation unit 90j.

[0022] To realize the required drive torque Tr_dem, the engine control unit 90a controls the engine torque Te [Nm] which is the output torque of the engine 12, the MG control unit 90b controls the MG torque Tmg [Nm] which is the output torque of the electric motor MG, and the transmission control unit 90c controls the gear ratio γat of the automatic transmission 22. The K0 control unit 90d controls the engagement and disengagement of the clutch K0. The WSC control unit 90e controls the engagement and disengagement of the clutch WSC.

[0023] The warm-up determination unit 90f determines whether or not the catalyst 54 needs to be warmed up. The catalyst temperature THcat, which is the temperature of the catalyst 54, is controlled within a predetermined allowable operating temperature range in which the purification action of the catalyst 54 is efficient and the catalyst 54 is not damaged. If the catalyst temperature THcat is lower than the predetermined allowable operating temperature range, it is determined that warm-up is necessary. In warm-up, the exhaust temperature THex [°C], which is the temperature of the exhaust gas, is increased by controlling the operation of the engine 12, thereby raising the catalyst temperature THcat. On the other hand, if the catalyst temperature THcat is within the predetermined allowable operating temperature range, it is determined that warm-up is not necessary.

[0024] The data acquisition unit 90g acquires data on the state of charge value SOC [%], the chargeable power Win [W], the plate temperature THplt, and the input shaft rotation speed Nin. The state of charge value SOC is the ratio of the amount of charge actually stored to a predetermined full charge capacity. The state of charge value SOC is calculated, for example, based on the battery charge / discharge current Ibat and the battery voltage Vbat. The chargeable power Win is the input power that specifies the limit of the input power of the battery 64. The chargeable power Win is calculated, for example, based on the battery temperature THbat and the state of charge value SOC of the battery 64. The MG rotation speed Nmg is the input side rotation speed of the clutch WSC. The input shaft rotation speed Nin is the output side rotation speed of the clutch WSC, and is uniquely determined by the vehicle speed V and the gear ratio γat of the automatic transmission 22. This uniquely determined input shaft rotation speed Nin is equivalent to the difference between the MG rotation speed Nmg and the clutch WSC differential rotation ΔWSC (=Nmg-Nin) when the clutch WSC is in a disengaged state. These data are parameters for calculating the slip amount SLP described below. The input shaft rotation speed Nin corresponds to the "output side rotation speed of the second clutch" in this invention.

[0025] The slip permission / prohibition determination unit 90h determines whether or not it is permitted to put the clutch WSC into a slip state. Specifically, it is determined whether or not the clutch WSC can withstand the amount of heat generated as a thermal load when the clutch WSC is put into a slip state and the battery 64 can charge the amount of power generated by the electric motor MG. For example, if any of the following is true: the state of charge value SOC is equal to or greater than a predetermined state determination value SOC_jdg, the chargeable power Win is equal to or less than a predetermined power determination value Win_jdg, the plate temperature THplt is equal to or greater than a predetermined temperature determination value THplt_jdg, or the input shaft rotation speed Nin is equal to or less than a predetermined speed determination value Nin_jdg, the clutch WSC is prohibited from being put into a slip state, and otherwise the clutch WSC is permitted to be put into a slip state. The predetermined state judgment value SOC_jdg, the predetermined power judgment value Win_jdg, the predetermined temperature judgment value THplt_jdg, and the predetermined speed judgment value Nin_jdg are judgment values ​​that have been experimentally or by design determined in advance as a thermal load that cannot be tolerated when the clutch WSC is in a slip state, or as a thermal load that cannot be charged to the battery 64 by the amount of heat generated by the electric motor MG.

[0026] The slip amount calculation unit 90i calculates the slip amount SLP [rpm], which is the differential rotation ΔWSC in the slip state, based on, for example, a slip amount calculation map and data acquired by the data acquisition unit 90g. The slip amount calculation map is a relationship between the state of charge value SOC, the chargeable power Win, the plate temperature THplt, the input shaft rotation speed Nin, and the slip amount SLP that is experimentally or design-based and stored in advance. Specifically, the slip amount SLP is calculated by inputting the actual state of charge value SOC, the chargeable power Win, the plate temperature THplt, and the input shaft rotation speed Nin into the slip amount calculation map.

[0027] The loss calculation unit 90j calculates the loss torque Tloss [Nm] in the clutch WSC. The loss torque Tloss is the torque that is not transmitted to the pair of drive wheels 14 out of the engine torque Te and is lost in the clutch WSC. The loss torque Tloss is calculated using a loss torque map, which is a relationship experimentally or designedly obtained and stored in advance between, for example, at least one of the slip amount SLP, the input-side rotational speed (= Nmg) and the output-side rotational speed (= Nin) of the clutch WSC, and the hydraulic pressure supplied to the actuator that performs the on / off control of the clutch WSC corresponding to the transmission torque of the clutch WSC, and the loss torque Tloss.

[0028] In engine driving, when it is determined that it is permissible to put the clutch WSC in a slip state, the engine command power Pe_cmd [W] is calculated from the engine power Pe_warm required for warming up the catalyst 54, the engine power Pe_dem required to realize the required drive torque Tr_dem, and the engine power Pe_loss for compensating for the loss torque Tloss. When the electric motor MG is in a driven state (during regeneration), the engine power Pe_dem is the power for transmitting the required drive torque Tr_dem to the pair of drive wheels 14 while compensating for the MG torque Tmg which is a negative torque. When the electric motor MG is in a driving state, the engine power Pe_dem is the power obtained by subtracting the power corresponding to the positive MG torque Tmg from the power for transmitting the required drive torque Tr_dem to the pair of drive wheels 14. During the warm-up of the catalyst 54, the engine control unit 90a controls the operation of the engine 12 so that the output of the engine 12 becomes the engine command power Pe_cmd. The K0 control unit 90d controls so that the clutch K0 is in an engaged state, and the WSC control unit 90e controls so that the clutch WSC is in a slip state with the slip amount SLP.

[0029] When it is determined that putting the clutch WSC into a slip state is prohibited during engine running, for example, switching to BEV running is performed, and engine command power Pe_cmd is set to engine power Pe for the friction of the engine 12, and the engine 12 is operated independently for warming up. Note that when the vehicle is stopped, the clutch K0 may be engaged and the clutch WSC may be released, and the engine command power Pe_cmd may be set to engine power Pe for the friction of the engine 12, and the engine 12 may be operated independently for warming up.

[0030] Fig. 2 is an example of a flowchart illustrating the control operation of the electronic control device 90 shown in Fig. 1. The flowchart in Fig. 2 is repeatedly executed.

[0031] First, in step (hereinafter, step will be omitted) S10, it is determined whether or not the catalyst 54 needs to be warmed up. If the determination in S10 is YES, data required to calculate the slip amount SLP is acquired in S20, and it is determined in S30 whether or not it is permitted to put the clutch WSC in a slip state. If the determination in S30 is YES, the slip amount SLP is calculated in S40, the torque loss Tloss is calculated in S50, and the clutch WSC is put in a slip state so that the clutch K0 is in an engaged state and has the slip amount SLP in S60, thereby warming up the catalyst 54. If the determination in S30 is NO, the clutch K0 is released and the clutch WSC is engaged in S70, thereby warming up the catalyst 54. The engine command power Pe_cmd in S60 is greater than the engine command power Pe_cmd in S70, and the time required to warm up the catalyst 54 is shortened. After execution of S60 and after execution of S70, in both cases, engine command power Pe_cmd is calculated in S80, and in S90, the operation of the engine 12 is controlled so that the output of the engine 12 becomes engine command power Pe_cmd. If the determination in S10 is NO, in S100, connection / disconnection control of the clutch K0 and the clutch WSC is executed according to predetermined control requests for the clutch K0 and the clutch WSC when the catalyst 54 is not warming up. After execution of S90 and after execution of S100, in both cases, the process returns.

[0032] According to this embodiment, the electronic control device 90 controls the clutch K0 to an engaged state while warming up the catalyst 54 that purifies the exhaust gas of the engine 12, and also controls the clutch WSC to a slip state with an amount of slip SLP calculated based on the state of charge value SOC, the chargeable power Win, the plate temperature THplt, and the input shaft rotation speed Nin which is the output side rotation speed of the clutch WSC. This shortens the time required to warm up the catalyst 54 and suppresses deterioration of the exhaust purification performance even when the vehicle speed is low or the required drive torque Tr_dem is low.

[0033] It should be noted that the above is an embodiment of the present invention, and the present invention can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art without departing from the spirit of the present invention. [Explanation of symbols]

[0034] 10: vehicle, 12: engine, 14: pair of drive wheels, 54: catalyst, 64: battery, 90: electronic control device (control device), K0: clutch (first clutch), MG: electric motor, Nin: input shaft rotation speed (output side rotation speed of second clutch), SLP: slip amount, SOC: state of charge value, THplt: plate temperature (temperature of second clutch), Win: chargeable power, WSC: clutch (second clutch)

Claims

[Claim 1] A control device for a vehicle including an engine and an electric motor, a first clutch that connects and disconnects power transmission between the engine and the electric motor, a second clutch that connects and disconnects power transmission between the electric motor and a pair of drive wheels, and a battery that exchanges electric power with the electric motor, During warm-up of a catalyst that purifies exhaust gas from the engine, the first clutch is controlled to an engaged state, and the second clutch is controlled to a slip state with an amount of slip calculated based on a state-of-charge value of the battery, a chargeable power of the battery, a temperature of the second clutch, and an output side rotation speed of the second clutch. A vehicle control device comprising:

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