Hybrid Vehicles

Abstract

To provide a hybrid vehicle in which restart of a control device during travelling is easy to be recognized by a driver.SOLUTION: (a) An electronic control device 100 controls travelling drive force transmitted from a travelling drive force source PG to a driving wheel 14. (b) The electronic control device 100 executes control for stopping an engine 12 when predetermined conditions including a neutral state of an automatic transmission 28 are established. (c) The electronic control device 100 which is restarted during travelling starts the engine 12 when the automatic transmission 28 is in the neutral state and continues operation of the started engine 12 although the predetermined conditions are established when the neutral state of the automatic transmission 28 continues.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a hybrid vehicle that includes an internal combustion engine and an electric motor as driving power sources for driving, a power transmission device provided in a power transmission path between the driving power sources for driving and drive wheels, and a control device that controls the driving power sources for driving and the power transmission device. [Background technology]

[0002] There is known a hybrid vehicle that includes an internal combustion engine and an electric motor as a driving force source for driving, a power transmission device provided in a power transmission path between the driving force source for driving and the drive wheels, and a control device that controls the driving force source for driving and the power transmission device. For example, the hybrid vehicle described in Patent Document 1 is such a vehicle. In the hybrid vehicle described in Patent Document 1, the control device that is restarted while the vehicle is traveling starts the driving force source for driving (the internal combustion engine and the electric motor) with the power transmission device in a neutral state before the vehicle stops traveling. The start of the internal combustion engine as the driving force source for driving makes it easy for the driver to recognize that the control device has been restarted. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-139223 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in order to suppress fuel consumption in an internal combustion engine, there is a fuel cut control that stops the supply of fuel to the internal combustion engine during coasting (coasting with the power transmission device in neutral) with the accelerator pedal not depressed. In the hybrid vehicle described in Patent Document 1, when the fuel cut control is adopted, there is a risk that the control device restarted during traveling will immediately stop the internal combustion engine by the fuel cut control, even though the internal combustion engine, which is the driving force source for traveling, was started with the power transmission device in neutral. If the internal combustion engine is stopped immediately after starting in this way, there is a risk that the driver will not recognize that the control device has been restarted.

[0005] The present invention has been made against the background of the above circumstances, and its object is to provide a hybrid vehicle in which the driver can easily recognize that the control device has been restarted while driving. [Means for solving the problem]

[0006] The gist of the present invention is a hybrid vehicle comprising an internal combustion engine and an electric motor as a driving force source for driving the vehicle, a power transmission device provided in a power transmission path between the driving force source for driving the vehicle and drive wheels, and a control device that controls the driving force source for driving the vehicle and the power transmission device, wherein (a) the control device controls the driving force for driving transmitted from the driving force source for driving the vehicle to the drive wheels, (b) the control device executes control to stop the internal combustion engine when predetermined conditions are met including the power transmission device being in a neutral state, and (c) when restarted while the vehicle is traveling, the control device starts the internal combustion engine when the power transmission device is in a neutral state, and continues operation of the started internal combustion engine even if the predetermined conditions are met if the neutral state of the power transmission device remains. Effect of the Invention

[0007] According to the hybrid vehicle of the present invention, (a) the control device controls the driving force for driving transmitted from the driving force source for driving to the drive wheels, (b) the control device executes control to stop the internal combustion engine when a predetermined condition including the power transmission device being in a neutral state is satisfied, and (c) the control device restarted while traveling starts the internal combustion engine when the power transmission device is in a neutral state, and continues the operation of the started internal combustion engine even if the predetermined condition is satisfied when the power transmission device is in a neutral state and the neutral state of the power transmission device continues. In this way, the control device restarted while traveling starts the internal combustion engine when the power transmission device is in a neutral state, and continues the operation of the started internal combustion engine even if the predetermined condition for stopping the internal combustion engine is satisfied when the neutral state of the power transmission device continues. As a result, the started internal combustion engine is not immediately stopped when the neutral state of the power transmission device continues, so that the driver can easily recognize that the control device has been restarted while traveling. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram of a hybrid vehicle 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 hybrid 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 following 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 hybrid vehicle 10 (hereinafter simply referred to as “vehicle 10”) according to an embodiment of the present invention, and is also a functional block diagram showing the main parts of control functions for various controls in vehicle 10.

[0011] The vehicle 10 is a hybrid vehicle equipped with an engine 12 and an electric motor MG, which are driving force sources PG for traveling. A power transmission path PT is between the driving force sources PG (engine 12, electric motor MG) for traveling and the driving wheels 14. The vehicle 10 is equipped with an engine connecting shaft 20, a clutch K0, an electric motor connecting shaft 22, a torque converter 24, an AT input shaft 26, which is an input rotating member of the automatic transmission 28, an automatic transmission 28, and the like, in order from the engine 12 side, in the power transmission path PT inside a case 18, which is a non-rotating member attached to the vehicle body. The vehicle 10 is also equipped with a differential gear 32 connected to an AT output shaft 30, which is an output rotating member of the automatic transmission 28, a pair of drive shafts 34 connected to the differential gear 32, and the like, in the power transmission path PT. The vehicle 10 is also equipped with an inverter 52, a hydraulic control circuit 54, an EOP 56, which is an electric oil pump, a battery 60, a shift lever 90, a power switch 94, and an electronic control device 100.

[0012] The engine 12 is a well-known internal combustion engine. An electronic control device 100 (described later) controls an engine control device 50 including a throttle actuator, a fuel injection device, an ignition device, and the like provided in the vehicle 10, thereby controlling the engine torque Te [Nm] outputted from the engine 12. In this specification, the terms torque, driving force, power, and force (power) are synonymous unless otherwise specified.

[0013] The engine connecting shaft 20 is a member that connects the engine 12 and the clutch K0, and is, for example, a crankshaft.

[0014] The electric motor MG is a so-called motor generator having a function as an electric motor that generates mechanical power from electric energy (electric motor function) and a function as a generator that generates electric energy from mechanical power (generator function). In this specification, power is synonymous with driving force, torque, and force unless otherwise specified. The electric motor MG is connected to a battery 60 provided in the vehicle 10 via an inverter 52 described later. The battery 60 is an electricity storage device that supplies and receives electric power to the electric motor MG. The electric motor MG controls the inverter 52 by an electronic control device 100 described later, thereby controlling the electric motor torque Tmg [Nm], which is the output torque of the electric motor MG. The electric motor MG corresponds to the "electric motor" in the present invention.

[0015] A clutch K0 is provided between an engine connecting shaft 20 connected to the engine 12 and an electric motor connecting shaft 22 connected to a rotor of the electric motor MG. The clutch K0 is an engagement device capable of connecting and disconnecting power transmission between the engine 12 and the electric motor connecting shaft 22, and is, for example, a wet-type multi-plate hydraulic friction engagement device. When the clutch K0 is in an engaged state, the clutch K0 enables power transmission between the engine 12 and the electric motor MG. When the clutch K0 is in a released state, the clutch K0 cuts off the power transmission between the engine 12 and the electric motor MG. When the clutch K0 is in a half-engaged state, i.e., a slipping engagement state, the clutch K0 enables power transmission between the engine 12 and the electric motor MG according to a transmission torque capacity (engaging force of the clutch K0) based on the slipping engagement state.

[0016] The electric motor MG is driven to rotate by the electric power stored in the battery 60, and outputs the driving force for running the hybrid vehicle 10. The electric motor MG also generates electric power by the driving force for running input from the engine 12 via the clutch K0, and generates electric power by converting the driven force input from the drive wheels 14 side into electric power by regeneration. The generated electric power is charged to the battery 60 via the inverter 52.

[0017] The inverter 52 is a power supply circuit provided between the electric motor MG and the battery 60, and converts direct current to alternating current or alternating current to direct current under the control of the electronic control device 100. For example, the inverter 52 converts direct current supplied from the battery 60 to alternating current and outputs the alternating current to the electric motor MG to drive it, or converts alternating current generated by the electric motor MG to direct current and outputs the direct current to the battery 60.

[0018] The battery 60 is a chargeable and dischargeable secondary battery such as a lithium ion battery, a nickel metal hydride battery, etc. The battery 60 is mainly used to supply power for driving the electric motor MG and to store the electric power generated by the electric motor MG through regeneration.

[0019] The torque converter 24 is a well-known torque converter. The torque converter 24 includes a pump wheel connected to the motor connecting shaft 22, a turbine wheel connected to the AT input shaft 26, and a lock-up clutch 40 that directly connects the pump wheel and the turbine wheel. The torque converter 24 is disposed in a power transmission path PT between the driving force source PG (engine 12, motor MG) and the drive wheels 14, and is a fluid-type transmission device that can transmit the driving force for traveling output from the driving force source PG to the AT input shaft 26 via a fluid from the motor connecting shaft 22 to the AT input shaft 26. The vehicle 10 includes a MOP 42 that is a mechanical oil pump. The MOP 42 is connected to the pump wheel and is rotationally driven by the driving force source PG (engine 12, motor MG) to discharge hydraulic oil OIL used in each part in the case 18.

[0020] The EOP 56 is a known oil pump that can be driven by the rotation of an EOP drive motor 58, independently of the rotation of the engine 12 and electric motor MG, which are driving power sources PG for traveling. The EOP drive motor 58 is a known electric motor, and the rotation speed of the EOP drive motor 58 is controlled by an inverter (not shown) being controlled by the electronic control device 100. The EOP 56 is driven to rotate by the EOP drive motor 58, and discharges hydraulic oil OIL used in each portion within the case 18.

[0021] The automatic transmission 28 is a known automatic transmission that changes the speed of the driving force input from the driving force source PG (engine 12, electric motor MG) to the AT input shaft 26 and outputs the changed speed to the AT output shaft 30, and is, for example, a stepped transmission of a planetary gear type or a constant meshing parallel shaft type, or a continuously variable transmission of a belt type or a power roller type. The automatic transmission 28 is controlled by a hydraulic control circuit 54 controlled by the electronic control device 100 so that a desired speed ratio γat (=AT input rotation speed Ni [rpm] / AT output rotation speed No [rpm]) is formed by a hydraulic control circuit 54 controlled by the electronic control device 100. In this embodiment, the automatic transmission 28 is a known planetary gear type automatic transmission that includes a plurality of planetary gear devices and a plurality of shift engagement devices CB. Each of the shift engagement devices CB is switched between an engagement / disengagement state, such as a fully engaged state, a half-engaged state, and a disengaged state, by adjusting the hydraulic pressure supplied from the hydraulic control circuit 54 to a hydraulic actuator that controls the engagement / disengagement state of the shift engagement devices CB. The automatic transmission 28 forms one of a plurality of gear stages (also called gear stages) having different gear ratios γat by engaging one of the engagement devices of the shift engagement devices CB. The automatic transmission 28 can also be placed in a neutral state in which the driving force for traveling output from the driving force source PG is not transmitted to the drive wheels 14. The automatic transmission 28 corresponds to the "power transmission device" in this invention.

[0022] The differential gear 32 is a well-known differential gear that receives the driving force for traveling transmitted from the AT output shaft 30 of the automatic transmission 28 and transmits equal driving torque to a pair of drive shafts 34 while allowing an appropriate difference in rotational speed.

[0023] The shift operation positions POSsh of the shift lever 90 are, for example, each of the operation positions of the "P operation position", "R operation position", "N operation position" and "D operation position". The P operation position is a parking operation position that sets the automatic transmission 28 to the P range (= a range in which the automatic transmission 28 is in a neutral state and the AT output shaft 30 is mechanically fixed so as not to rotate). The R operation position is a reverse drive operation position that sets the automatic transmission 28 to the R range (= a range that allows the vehicle 10 to drive backwards). The N operation position is a neutral operation position that sets the automatic transmission 28 to the N range (= a range that is in a neutral state). The D operation position is a forward drive operation position that sets the automatic transmission 28 to the D range (= a range that allows forward drive by executing automatic shift control using all the gear stages of the automatic transmission 28). The driver selects one of the "P operating position," "R operating position," "N operating position," and "D operating position," thereby switching the shift range of the automatic transmission 28 to "P" (=P range), "R" (=R range), "N" (=N range), and "D" (=D range). In the shift ranges of the automatic transmission 28, "P" and "N" are non-driving ranges, and "R" and "D" are driving ranges.

[0024] The hydraulic control circuit 54 uses the hydraulic pressure of the hydraulic oil OIL discharged from the MOP 42 and the EOP 56 as the source pressure, and supplies the necessary hydraulic oil OIL to each part in the case 18. For example, the hydraulic control circuit 54 generates hydraulic pressure for controlling the engagement and disengagement of the clutch K0, hydraulic pressure for controlling the shifting of the automatic transmission 28, and hydraulic pressure for controlling the engagement and disengagement of the lock-up clutch 40 of the torque converter 24, and supplies these to each hydraulic actuator in the case 18.

[0025] When the clutch K0 is engaged, the driving force for traveling output from the engine 12 is transmitted from the engine connecting shaft 20 through the clutch K0, the electric motor connecting shaft 22, the torque converter 24, the automatic transmission 28, the differential gear 32, the drive shaft 34, etc. in this order to the driving wheels 14. The driving force for traveling output from the electric motor MG is transmitted from the electric motor connecting shaft 22 through the torque converter 24, the automatic transmission 28, the differential gear 32, the drive shaft 34, etc. in this order to the driving wheels 14, regardless of whether the clutch K0 is engaged or disengaged.

[0026] In the vehicle 10, any one of the driving modes of the BEV driving mode, the engine driving mode, and the HEV driving mode can be selected. The BEV driving mode is a driving mode in which the engine 12 is stopped and the motor MG is powered to perform BEV (Battery Electric Vehicle) driving using only the motor MG as a driving force source among the driving force sources PG. The engine driving mode is a driving mode in which the clutch K0 is engaged and only the engine 12 as a driving force source among the driving force sources PG. The HEV driving mode is a driving mode in which the clutch K0 is engaged and HEV (Hybrid Electric Vehicle) driving using both the engine 12 and the motor MG as driving force sources among the driving force sources PG.

[0027] The driving mode of the vehicle 10 can be switched between the BEV driving mode, the engine driving mode, and the HEV driving mode, for example, by a driving force source switching map. The driving force source switching map is a relationship in which the driving mode is predefined in two-dimensional coordinates with the vehicle speed V [km / h] and the required driving torque Trdem [Nm] as variables, for example. The required driving torque Trdem is the driving torque Tr [Nm] required for the vehicle 10, for example, the driving torque required for the drive wheels 14. A method for calculating the required driving torque Trdem will be described later.

[0028] In general, the BEV driving mode is selected in a low vehicle speed region where the vehicle speed V is relatively low and a low load region where the required driving torque Trdem is relatively low (= a region where the accelerator opening θacc [%] is relatively low), where engine efficiency is reduced. On the other hand, in a high vehicle speed region where the vehicle speed V is relatively high, or in a high load region where the required driving torque Trdem is relatively high (= a region where the accelerator opening θacc is relatively high), the engine driving mode or the HEV driving mode is selected. The BEV driving mode is applied when the state of charge value SOC [%] of the battery 60 (the ratio of the amount of charge actually stored to a predetermined full charge capacity) is equal to or greater than a predetermined engine start threshold. In other words, when the state of charge value SOC of the battery 60 is less than a predetermined engine start threshold, there is no region in the driving force source switching map where the BEV driving mode is selected, and all the regions are the same as the region where the engine driving mode or the HEV driving mode is selected. In the engine driving mode or the HEV driving mode, the motor rotation speed Nmg [rpm] which is the rotation speed of the motor MG is equal to the engine rotation speed Ne [rpm] which is the rotation speed of the engine 12. The predetermined engine start threshold is a threshold set in advance for determining that the state of charge value SOC is at a value at which the engine 12 needs to be forcibly started to charge the battery 60.

[0029] The power switch 94 is a switch that allows the driver to request switching between starting and stopping of the electronic control device 100, which is a system for driving the vehicle 10, for each operation. For example, when the power switch 94 is operated (e.g., pressed and held) while driving, it is possible to stop the electronic control device 100. In addition, when the power switch 94 is operated (= when the driver requests restart) after the electronic control device 100 has been stopped while driving in this way, it is possible to restart the electronic control device 100. When the driver operates the power switch 94 to start the electronic control device 100, the power switch 94 outputs a start signal ST, which is a signal requesting start, to the electronic control device 100.

[0030] The electronic control device 100 includes a so-called microcomputer equipped with, for example, a CPU, RAM, ROM, an input / output interface, etc., and the CPU executes various controls of the vehicle 10 by performing signal processing according to a program previously stored in the ROM while utilizing the temporary storage function of the RAM. The electronic control device 100 includes computers for engine control, electric motor control, hydraulic control, etc. as necessary. The electronic control device 100 corresponds to the "control device" in the present invention.

[0031] The electronic control device 100 receives various signals based on detection values ​​from various sensors provided in the vehicle 10 (for example, an engine rotation speed sensor 70, a turbine rotation speed sensor 72, an output rotation speed sensor 74, an electric motor rotation speed sensor 76, an accelerator opening sensor 78, a brake operation amount sensor 80, a throttle valve opening sensor 82, a battery sensor 84, a shift position sensor 92, a power switch 94, etc.) (for example, an engine rotation speed Ne [rpm] which is the rotation speed of the engine 12, a turbine rotation speed Nt [rpm] which is the same value as the AT input rotation speed Ni [rpm], an AT output rotation speed No [rpm] which corresponds to the vehicle speed V, an electric motor rotation speed which is the rotation speed of the electric motor MG, etc.). The following are input: speed Nmg [rpm], accelerator opening θacc [%] which is the amount of accelerator operation by the driver representing the magnitude of the driver's acceleration operation, driver's brake operation amount θbrk [%] which represents the magnitude of the driver's deceleration operation, throttle valve opening θth [%] which is the opening of the electronic throttle valve, battery temperature THbat [°C], battery charge / discharge current Ibat [A] and battery voltage Vbat [V] of battery 60, shift operation position POSsh which represents the operating position of the shift lever 90 operated by the driver, start signal ST which is a signal requesting the start-up of electronic control unit 100 by the driver operating power switch 94, etc.

[0032] The electronic control device 100 outputs various command signals (e.g., an engine control signal Se for controlling the engine 12, an electric motor control signal Smg for controlling the electric motor MG, a shift control signal Sat for controlling the shift engagement device CB, a K0 control signal Sk0 for controlling the clutch K0, an LU control signal Slu for controlling the lock-up clutch 40, an EOP control signal Seop for controlling the EOP 56, etc.) to each device (e.g., an engine control device 50, an inverter 52, a hydraulic control circuit 54, an EOP drive motor 58, etc.) provided in the vehicle 10.

[0033] The electronic control unit 100 functionally comprises a hybrid control unit 102 , a clutch control unit 104 , a gear shift control unit 106 , a fuel cut determination unit 108 , a restart determination unit 110 , and a start continuation determination unit 112 .

[0034] The hybrid control unit 102 functionally comprises an engine control unit 102a that controls the operation of the engine 12, and an electric motor control unit 102b that controls the operation of the electric motor MG via the inverter 52, and executes hybrid drive control using the engine 12 and the electric motor MG, etc., using these control functions.

[0035] The hybrid control unit 102 calculates the driver's required driving amount (e.g., required driving torque Trdem) for the vehicle 10 by applying the actual accelerator opening θacc and vehicle speed V to a required driving amount map, for example. The required driving amount map is a map in which the relationship between the accelerator opening θacc and vehicle speed V and the required driving amount is determined in advance experimentally or by design and stored. The required driving amount is the driving amount required for the vehicle 10, for example, the required driving torque Trdem. In other words, the required driving torque Trdem is the required driving power Prdem [W] at the vehicle speed V at that time. As the required driving amount, the required driving force Frdem [N] at the drive wheels 14, the required output torque at the AT output shaft 30, etc. can also be used. In calculating the required driving amount, the AT output rotation speed No, etc. may be used instead of the vehicle speed V. In this way, the required driving torque Trdem, the required driving power Prdem, the required driving force Frdem, and the required output torque at the AT output shaft 30 are synonymous in that they are the required driving amounts of the vehicle 10.

[0036] The hybrid control unit 102 outputs an engine control signal Se for controlling the engine 12 and an electric motor control signal Smg for controlling the electric motor MG so as to realize the required driving power Prdem, taking into consideration the transmission loss, the auxiliary load, the gear ratio γat of the automatic transmission 28, the chargeable electric power Win [W] and the dischargeable electric power Wout [W] of the battery 60, etc. The engine control signal Se is, for example, a command value for the engine power Pe [W], which is the power of the engine 12 that outputs the engine torque Te at the engine rotation speed Ne at that time. The electric motor control signal Smg is, for example, a command value for the power consumption Wm [W] of the electric motor MG that outputs the electric motor torque Tmg at the electric motor rotation speed Nmg at that time.

[0037] The chargeable power Win of the battery 60 is the maximum power that can be input, which specifies the limit on the input power of the battery 60, and indicates the input limit of the battery 60. The dischargeable power Wout of the battery 60 is the maximum power that can be output, which specifies the limit on the output power of the battery 60, and indicates the output limit of the battery 60. The chargeable power Win and dischargeable power Wout of the battery 60 are calculated by the electronic control device 100 based on, for example, the battery temperature THbat and the state of charge value SOC of the battery 60.

[0038] The hybrid control unit 102 controls the vehicle 10 in a driving mode (BEV driving mode, engine driving mode, HEV driving mode) according to the state of the vehicle 10. For example, the driving mode according to the state of the vehicle 10 is selected by the driving power source switching map described above.

[0039] The engine control unit 102a controls the engine torque Te so as to realize the required driving amount for the vehicle 10. The motor control unit 102b executes torque control to control the motor torque Tmg so as to realize the required driving amount for the vehicle 10 while traveling in an accelerator-on state. The accelerator-on state is a vehicle state in which the driver operates the accelerator (for example, the driver depresses the accelerator pedal Acc) and the accelerator opening θacc is greater than zero. The torque control is a control to make the motor torque Tmg become a predetermined target torque so as to realize the required driving amount for the vehicle 10. Specifically, in traveling in the BEV traveling mode, the motor control unit 102b controls the motor torque Tmg so as to realize the required driving torque Trdem. In traveling in the engine traveling mode, the engine control unit 102a controls the engine torque Te so as to realize the entire required driving torque Trdem, and in the case where there is a surplus of the engine torque Te with respect to the required driving torque Trdem, the motor control unit 102b controls the motor torque Tmg so as to generate electricity with the surplus. When driving in the HEV driving mode, the engine control unit 102a controls the engine torque Te to realize a portion of the required driving torque Trdem, and the electric motor control unit 102b controls the electric motor torque Tmg to compensate for the torque that is insufficient in the engine torque Te relative to the required driving torque Trdem.

[0040] The hybrid control unit 102 further includes a starting control unit 102c. The starting control unit 102c and the clutch control unit 104 execute engine starting control to crank the engine 12 using the electric motor MG and the clutch K0 as necessary to start the engine 12. Specifically, the starting control unit 102c controls the electric motor MG to output a cranking torque Tcr [Nm] until cranking ends, in accordance with the switching of the clutch K0 from a released state to an engaged state by the clutch control unit 104. The starting control unit 102c also controls fuel supply to the engine 12, ignition, and the like, in conjunction with the cranking of the engine 12 by the clutch K0 and the electric motor MG.

[0041] The shift control unit 106 judges whether or not to shift the automatic transmission 28 by using, for example, a shift map, and outputs a shift control signal Sat for executing shift control as necessary to the hydraulic control circuit 54. The shift map is a predetermined relationship having a shift line for judging whether or not to shift the automatic transmission 28 on a two-dimensional coordinate system having, for example, vehicle speed V and required driving torque Trdem as variables. In the shift map, the AT output rotation speed No may be used instead of the vehicle speed V, and the required driving force Frdem, accelerator opening θacc, throttle valve opening θth, etc. may be used instead of the required driving torque Trdem.

[0042] The fuel cut determination unit 108 determines whether or not a predetermined condition for executing fuel cut control is satisfied when the engine 12 is in an operating state. For example, the predetermined condition is that the automatic transmission 28 is in a neutral state and the vehicle is coasting without the driver performing an accelerator operation or a brake operation. For example, when the accelerator opening θacc is less than a predetermined opening determination value θacc_jdg and the brake operation amount θbrk is less than a predetermined operation amount determination value θbrk_jdg, it is determined that the driver is not performing an accelerator operation or a brake operation. The predetermined opening determination value θacc_jdg is a predetermined determination value for determining that the driver is not performing an accelerator operation. The predetermined operation amount determination value θbrk_jdg is a predetermined determination value for determining that the driver is not performing a brake operation.

[0043] When the fuel cut determination unit 108 determines that the predetermined condition for executing the fuel cut control is satisfied, the engine control unit 102a executes the fuel cut control to cause the fuel injection device to stop the supply of fuel to the engine 12, thereby stopping the operation of the engine 12. When the fuel cut determination unit 108 determines that the predetermined condition for executing the fuel cut control is not satisfied, the engine control unit 102a does not execute the fuel cut control to cause the fuel injection device to stop the supply of fuel to the engine 12, thereby allowing the operation state of the engine 12 to continue. The fuel cut control corresponds to "control to stop an internal combustion engine" in the present invention.

[0044] Now, a case where the electronic control unit 100 is restarted while the vehicle is running will be described.

[0045] The restart determination unit 110 determines whether the electronic control unit 100 has been restarted while the vehicle is traveling. For example, when the vehicle speed V is higher than a predetermined stopped vehicle speed value V_stp, it is determined that the vehicle is traveling. The predetermined stopped vehicle speed value V_stp is a determination value near zero that is set in advance to determine that the vehicle is stopped. In addition, when a start signal ST is output by operating the power switch 94 to start the electronic control unit 100, it is determined that the electronic control unit 100 has been restarted.

[0046] When the restart determination unit 110 determines that the electronic control unit 100 has been restarted during driving, the start control unit 102c and the clutch control unit 104 execute engine start control to start the engine 12. The start control of the engine 12 is executed when the automatic transmission 28 is in a neutral state.

[0047] When the engine 12 is started by the start control unit 102c and the clutch control unit 104, the start continuation determination unit 112 determines whether or not the neutral state of the automatic transmission 28 continues after the start of the engine 12. For example, if the driver selects the "N operation position" with the shift lever 90 and then operates the power switch 94 to restart the electronic control unit 100, the engine 12 is started by the electronic control unit 100 after the restart, and if the driver continues to select the operation position of the "N operation position" after the start of the engine 12, it is determined that the neutral state of the automatic transmission 28 continues. On the other hand, if the driver selects an operation position other than the "N operation position" (for example, if the "D operation position" is selected) after the start of the engine 12, it is determined that the neutral state of the automatic transmission 28 does not continue.

[0048] When the start continuation determination unit 112 determines that the neutral state of the automatic transmission 28 continues, the engine control unit 102a continues the operation of the engine 12. When the start continuation determination unit 112 determines that the neutral state of the automatic transmission 28 does not continue, the engine control unit 102a stops the operation of the engine 12.

[0049] Fig. 2 is an example of a flowchart illustrating the control operation of the electronic control unit 100 shown in Fig. 1. The flowchart in Fig. 2 is repeatedly executed while the vehicle is traveling.

[0050] First, in step S10 (hereinafter, step will be omitted) corresponding to the functions of the restart determination unit 110, the start control unit 102c, and the clutch control unit 104, it is determined whether or not the start control of the engine 12 has been executed by restarting the electronic control unit 100 during driving. If the determination in S10 is positive, it is determined in S20 corresponding to the function of the start continuation determination unit 112 whether or not the driver continues to select the operation position of the "N operation position". If the determination in S10 is negative, the process returns. If the determination in S10 is negative, the engine 12 is started or stopped depending on the vehicle state. For example, the engine 12 is started or stopped using the driving force source switching map described above.

[0051] If the determination in S20 is positive, then in S30, which corresponds to the function of the engine control unit 102a, an engine operation continuation request signal for requesting continuation of the operating state of the started engine 12 is set to ON, the operation of the engine 12 is continued, and then the process returns. If the determination in S20 is negative, then in S40, which corresponds to the function of the engine control unit 102a, an engine operation continuation request signal for requesting continuation of the operating state of the started engine 12 is set to OFF, the operation of the engine 12 is stopped, and then the process returns.

[0052] According to this embodiment, (a) the electronic control unit 100 controls the driving force for driving transmitted from the driving force source PG to the drive wheels 14, (b) the electronic control unit 100 executes fuel cut control to stop the engine 12 when a predetermined condition including the automatic transmission 28 being in neutral is satisfied, and (c) the electronic control unit 100 restarted while traveling starts the engine 12 when the automatic transmission 28 is in neutral, and continues the operation of the started engine 12 even if a predetermined condition is satisfied when the automatic transmission 28 is in neutral and the automatic transmission 28 is in neutral. In this way, the electronic control unit 100 restarted while traveling starts the engine 12 when the automatic transmission 28 is in neutral, and continues the operation of the started engine 12 even if a predetermined condition for stopping the engine 12 is satisfied when the automatic transmission 28 is in neutral and the automatic transmission 28 is in neutral. As a result, the started engine 12 is not immediately stopped while the automatic transmission 28 remains in neutral, making it easier for the driver to recognize that the electronic control device 100 has restarted while driving.

[0053] Although the embodiment of the present invention has been described in detail above with reference to the drawings, the present invention can be applied to other embodiments.

[0054] In the above-described embodiment, the torque converter 24, which is a fluid-type power transmission device, is provided in the power transmission path PT between the driving power source PG for driving and the automatic transmission 28, but the present invention is not limited to this embodiment. For example, other fluid-type power transmission devices, such as a fluid coupling that does not have a torque amplifying effect, may be used instead of the torque converter 24. Also, the fluid-type power transmission device does not necessarily have to be provided, and may be replaced with, for example, a starting clutch.

[0055] In the above-described embodiment, the "power transmission device" of the present invention is the automatic transmission 28 capable of achieving a neutral state in which the driving force for driving output from the driving force source PG is not transmitted to the drive wheels 14, but the present invention is not limited to this embodiment. For example, the "power transmission device" of the present invention may be the above-described starting clutch provided in place of the torque converter 24, which is a fluid transmission device. In other words, the "power transmission device" of the present invention may be a clutch capable of achieving a neutral state in which the driving force for driving output from the driving force source PG is not transmitted to the drive wheels 14.

[0056] In the above embodiment, the "control for stopping the internal combustion engine" in the present invention is the fuel cut control, but the present invention is not limited to this aspect and may be a control for stopping the internal combustion engine when a predetermined condition is satisfied, including the power transmission device being in a neutral state. The predetermined condition may be a condition that at least includes the power transmission device being in a neutral state.

[0057] It should be noted that the above is merely 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]

[0058] 10: Hybrid vehicles 12: Engine (internal combustion engine) 14: Drive wheel 28: Automatic transmission (power transmission device) 100: Electronic control device (control device) MG: Electric motor PG: Driving power source PT: Power transmission path

Claims

[Claim 1] A hybrid vehicle including an internal combustion engine and an electric motor as a driving force source for driving, a power transmission device provided in a power transmission path between the driving force source for driving and a drive wheel, and a control device that controls the driving force source for driving and the power transmission device, The control device controls a driving force for traveling transmitted from the driving force source for traveling to the drive wheels, the control device executes control to stop the internal combustion engine when a predetermined condition is satisfied, including the power transmission device being in a neutral state; The control device, which is restarted during traveling, starts the internal combustion engine when the power transmission device is in a neutral state, and, if the neutral state of the power transmission device continues, continues the operation of the started internal combustion engine even if the predetermined condition is satisfied. A hybrid vehicle characterized by

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