Hybrid vehicles

Abstract

To suppress a feeling of strangeness from being given to a driver.SOLUTION: A hybrid vehicle comprises: an engine; a motor; a clutch provided between the engine and the motor; a speed changer whose input shaft is connected to the motor and whose output shaft is connected to a driving wheel; and a control device that executes starting control by which the clutch and the engine are controlled so that the engine is started together with increase in a rotation speed of the engine caused by slip-engagement of the clutch, when starting the engine during travelling. When a condition for starting the engine is satisfied during travelling, the control device executes the starting control when an allowance time until starting upshift of the speed changer is equal to or longer than a predetermined time, and executes the starting control after completing the upshift, when the allowance time is less than the predetermined time.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] Conventionally, hybrid vehicles of this type have been proposed that include an engine and a motor as power sources, and a transmission provided between the engine and the motor and the drive wheels, and that run in a number of driving modes with different operating states of the engine and the motor (see, for example, Patent Document 1). In these hybrid vehicles, driving mode switching is prohibited when a gear change that changes the gear ratio of the transmission is performed, and changing the gear ratio of the transmission is prohibited when a mode change that switches between driving modes is performed. In this way, the occurrence of shocks caused by simultaneously switching driving modes and changing the gear ratio is suppressed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-2241 Summary of the Invention [Problem to be solved by the invention]

[0004] In a hybrid vehicle that has a clutch between the engine and the motor in addition to the above-mentioned hardware configuration, if the transmission is upshifted relatively quickly after the engine has been started, the increase in engine speed when the engine is started and the decrease in engine speed associated with the transmission upshift will occur in a relatively short time, which may cause discomfort to the driver.

[0005] The hybrid vehicle of the present invention has a main object to suppress any sense of discomfort felt by the driver. [Means for solving the problem]

[0006] The hybrid vehicle of the present invention employs the following means to achieve the above-mentioned main object.

[0007] The hybrid vehicle of the present invention is an engine and a motor; a clutch provided between the engine and the motor; a transmission having an input shaft connected to the motor and an output shaft connected to drive wheels; a control device that executes start control to control the clutch and the engine so that, when starting the engine while the vehicle is running, the engine is started with an increase in engine speed due to slip engagement of the clutch; A hybrid vehicle comprising: The control device When the engine start condition is met while the vehicle is running, When the grace time until the start of the upshift of the transmission is equal to or longer than a predetermined time, the start control is executed. When the grace period is less than the predetermined period, the start control is executed after the upshift is completed. The gist of this is as follows.

[0008] In the hybrid vehicle of the present invention, when starting the engine while the vehicle is traveling (with the motor and transmission input shaft rotating), start control is executed to control the clutch and engine so that the engine starts with an increase in engine speed due to slip engagement of the clutch. In this case, when the engine start condition is met while the vehicle is traveling, if the grace period until the start of an upshift of the transmission is equal to or longer than a predetermined period, start control is executed, and if the grace period is shorter than the predetermined period, start control is executed after the upshift is completed. This makes it possible to prevent the transmission from upshifting relatively quickly after the completion of engine start (increasing and decreasing the engine speed in a relatively short period). As a result, it is possible to prevent the driver from feeling uncomfortable.

[0009] In the hybrid vehicle of the present invention, when the start condition is satisfied while the vehicle is running, the control device may execute the start control without waiting for the upshift to be completed, even if the grace period is shorter than the predetermined period, as long as the rotation speed of the input shaft of the transmission is equal to or greater than a predetermined rotation speed. This prevents the clutch from becoming relatively hot. This is based on the fact that the clutch is more likely to generate heat the higher the rotation speed of the input shaft of the transmission when the start control is executed.

[0010] In the hybrid vehicle of the present invention, when the starting condition is met while the vehicle is running, the control device may execute the starting control without waiting for the upshift if the grace time less than the predetermined time has elapsed and no upshift is requested.

[0011] In the hybrid vehicle of the present invention, when the starting condition is met while the vehicle is traveling, the control device may predict the grace period based on at least one of an accelerator operation amount, a vehicle speed, a vehicle acceleration, a required torque for traveling, a road gradient, and a traveling resistance. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram showing an outline of the configuration of a hybrid vehicle 20 as an embodiment of the present invention. [Figure 2] FIG. 2 is an explanatory diagram showing an example of a shift diagram of the transmission 40. [Figure 3] 10 is a flowchart showing an example of a processing routine executed by the HVECU 70. [Figure 4] 10 is a time chart showing an example of the accelerator opening Acc, whether the starting conditions of the engine 22 are met, the target gear M* and gear M of the transmission 40, the rotation speed Ne of the engine 22, the rotation speed Ni of the input shaft 41 of the transmission 40, and the temperature Tcl of the clutch K0 in an embodiment and a comparative example. [Figure 5] 10 is a flowchart showing an example of a processing routine executed by the HVECU 70. [Figure 6] 10 is a flowchart showing an example of a processing routine executed by the HVECU 70. DETAILED DESCRIPTION OF THE INVENTION

[0013] Next, a mode for carrying out the present invention will be described using examples. [Example]

[0014] 1 is a diagram showing an outline of the configuration of a hybrid vehicle 20 according to one embodiment of the present invention. As shown in the figure, the hybrid vehicle 20 of the embodiment includes an engine 22, an engine electronic control unit (hereinafter referred to as "engine ECU") 24, a motor 30, an inverter 32, a motor electronic control unit (hereinafter referred to as "motor ECU") 34, a clutch K0, a clutch WSC, a transmission 40, a hydraulic control device 44, a transmission electronic control unit (hereinafter referred to as "transmission ECU") 46, a battery 50 as an electricity storage device, a battery electronic control unit (hereinafter referred to as "battery ECU") 52, and a hybrid electronic control unit (hereinafter referred to as "HVECU") 70.

[0015] The engine 22 is configured as an internal combustion engine that outputs power using fuel such as gasoline or diesel fuel from a fuel tank. A crankshaft 23 of the engine 22 is connected to a rotary shaft 31 of a motor 30 via a clutch K0.

[0016] The engine ECU 24 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports (not shown). Signals from various sensors are input to the engine ECU 24 via input ports. Examples of the signals input to the engine ECU 24 include a crank angle θcr from a crank position sensor 23a that detects the rotational position of the crankshaft 23 of the engine 22, a coolant temperature Tw from a water temperature sensor that detects the temperature of the coolant in the engine 22, and an intake air amount Qa from an air flow meter that detects the intake air amount of the engine 22. Various control signals are output from the engine ECU 24 via output ports. Examples of the signals output from the engine ECU 24 include a control signal for a throttle valve, a control signal for a fuel injection valve, and a control signal for a spark plug. The engine ECU 24 is connected to the HVECU 70 via communication ports. The engine ECU 24 calculates the engine speed Ne of the engine 22 based on the crank angle θcr of the crankshaft 23 from the crank position sensor 23a.

[0017] The motor 30 is configured as a synchronous generator motor and has a rotor with a permanent magnet embedded in the rotor core and a stator with a three-phase coil wound around the stator core. A rotating shaft 31 to which the rotor of the motor 30 is fixed is connected to the crankshaft 23 of the engine 22 via a clutch K0 and to the input shaft 41 of the transmission 40 via a clutch WSC. The inverter 32 is used to drive the motor 30 and is connected to the battery 50 via a power line 54. The motor 30 is rotationally driven by switching of multiple switching elements of the inverter 32.

[0018] The motor ECU 34 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports (not shown). Signals from various sensors are input to the motor ECU 34 via the input port. Examples of signals input to the motor ECU 34 include a rotational position θm from a rotational position sensor 30a that detects the rotational position of the rotor (rotating shaft 31) of the motor 30, and phase currents Iu and Iv from current sensors that detect currents in each phase of the motor 30. The motor ECU 34 outputs control signals to the inverter 32 via the output port. The motor ECU 34 is connected to the HVECU 70 via the communication port. The motor ECU 34 calculates the rotational speed Nm of the motor 30 based on the rotational position θm of the rotor (rotating shaft 31) of the motor 30 from the rotational position sensor 30a.

[0019] The clutch K0 is configured as, for example, a hydraulically driven friction clutch, and connects and disconnects the crankshaft 23 of the engine 22 and the rotating shaft 31 of the motor 30. The clutch WSC is configured as, for example, a hydraulically driven friction clutch, and connects and disconnects the rotating shaft 31 of the motor 30 and the input shaft 41 of the transmission 40.

[0020] Transmission 40 is configured as a four-speed automatic transmission and has an input shaft 41, an output shaft 42, multiple planetary gears, and multiple hydraulically driven friction engagement elements (clutches and brakes). Input shaft 41 is connected to the rotor of motor 30 via clutch WSC, and output shaft 42 is connected to drive wheels 49 via differential gear 48. Each of the multiple friction engagement elements has a hydraulic servo composed of a piston, multiple friction engagement plates (friction plates and separator plates), an oil chamber to which hydraulic oil is supplied, and the like. Transmission 40 establishes forward gears (first to fourth gears) and reverse gears by engaging or disengaging the multiple friction engagement elements, thereby connecting input shaft 41 and output shaft 42 (transmitting power between them) or disconnecting input shaft 41 and output shaft 42.

[0021] The hydraulic control device 44 has a valve body with multiple oil passages formed therein, multiple regulator valves, multiple linear solenoid valves, etc. This hydraulic control device 44 adjusts the hydraulic pressure of the working oil from the mechanical oil pump or the electric oil pump and supplies it to the clutch K0, the clutch WSC, the multiple friction engagement elements of the transmission 40, etc.

[0022] Although not shown, the transmission ECU 46 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. Signals from various sensors are input to the transmission ECU 46 via input ports. Examples of signals input to the transmission ECU 46 include a rotation speed Ni from a rotation speed sensor 41a that detects the rotation speed of the input shaft 41 of the transmission 40, a rotation speed No from a rotation speed sensor 42a that detects the rotation speed of the output shaft 42 of the transmission 40, and an oil temperature Tho of the hydraulic oil in the hydraulic control device 44. Control signals and other signals to the hydraulic control device 44 are output from the transmission ECU 46 via output ports. The transmission ECU 46 is connected to the HVECU 70 via a communication port.

[0023] The battery 50 is configured as, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery, and as described above, is connected to the inverter 32 via a power line 54. The battery ECU 52 includes a microcomputer (not shown) having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. Signals from various sensors required for managing the battery 50 are input to the battery ECU 52 via an input port. Examples of signals input to the battery ECU 52 include a voltage Vb from a voltage sensor that detects the voltage of the battery 50, a current Ib (positive when discharging) from a current sensor that detects the current of the battery 50, and a temperature Tb from a temperature sensor that detects the temperature of the battery 50. The battery ECU 52 is connected to the HVECU 70 via the communication port. The battery ECU 52 calculates the state of charge (SOC) of the battery 50 based on an integrated value of the current Ib of the battery 50 from the current sensor.

[0024] Although not shown, the HVECU 70 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. Signals from various sensors are input to the HVECU 70 via the input ports. Examples of signals input to the HVECU 70 include a start signal from a start switch 80 and a shift position SP from a shift position sensor 82 that detects the operating position of a shift lever 81. Other examples of signals input to the HVECU 70 include an accelerator opening Acc from an accelerator pedal position sensor 84 that detects the depression amount of an accelerator pedal 83, and a brake pedal position BP from a brake pedal position sensor 86 that detects the depression amount of a brake pedal 85. Other examples of signals input to the HVECU 70 include a vehicle speed V from a vehicle speed sensor 87, a vehicle acceleration α from an acceleration sensor 88, and a road gradient θr from a gradient sensor 89. As described above, the HVECU 70 is connected to the engine ECU 24, the motor ECU 34, the transmission ECU 46, and the battery ECU 52 via the communication ports. The HVECU 70 calculates the running resistance Rr based on the vehicle speed V from the vehicle speed sensor 87 and the road surface gradient θr from the gradient sensor 89 .

[0025] The hybrid vehicle 20 of this embodiment configured as described above runs in a hybrid driving mode (HV driving) or an electric driving mode (EV driving) through cooperative control of the HVECU 70, engine ECU 24, motor ECU 34, and transmission ECU 46. The HV driving mode is a driving mode in which the clutches K0 and WSC are engaged and the engine 22 is rotating. The EV driving mode is a driving mode in which the clutch K0 is released and the clutch WSC is engaged and the engine 22 is not rotating. The engagement states of the clutches K0 and WSC include not only a fully engaged state but also a slipping engaged state.

[0026] In controlling the transmission 40 in the HV driving mode or the EV driving mode, the HVECU 70 sets a target gear M* of the transmission 40 based on the accelerator opening Acc, the vehicle speed V, and a shift map, and sends the set target gear M* to the transmission ECU 46. When the gear M of the transmission 40 matches the target gear M*, the transmission ECU 46 controls the hydraulic control device 44 to maintain the gear M, and when the gear M and the target gear M* differ, the transmission ECU 46 performs shift control (upshift or downshift) to control the hydraulic control device 44 so that the gear M matches the target gear M*. FIG. 2 is an explanatory diagram showing an example of a shift map of the transmission 40. In the figure, solid lines indicate upshift lines (upshift lines), and dashed lines indicate downshift lines (downshift lines).

[0027] The shift control first reduces the hydraulic pressure of a disengagement element, which is one of the multiple friction engagement elements and switches from an engaged state to a disengaged state, by one stage, while simultaneously executing stroke control of the engagement element. The stroke control involves a fast fill (stroking the piston) to close the gap between the piston of the engagement element and the friction engagement plate, and a low-pressure standby (low-pressure standby) to maintain the hydraulic pressure of the engagement element at a relatively low standby pressure. Next, the hydraulic pressure of the disengagement element is gradually reduced while the hydraulic pressure of the engagement element is gradually increased, shifting torque transmission from the disengagement element to the engagement element (torque phase). The hydraulic pressure of the disengagement element is gradually reduced while the hydraulic pressure of the engagement element is gradually increased, shifting the rotation speed Ni of the input shaft 41 of the transmission 40 to a rotation speed corresponding to the target gear M* (the gear M after the change) (inertia phase). When the rotation speed Ni of the input shaft 41 reaches the rotation speed corresponding to the target gear M*, the hydraulic pressure of the engagement element is further increased, completing the shift control. In the embodiment, when the shift control is executed, learning of the accelerator opening Acc, vehicle speed V, oil temperature Tho of the hydraulic oil in the hydraulic control device 44, etc. (hereinafter referred to as "shift learning") is performed.

[0028] In controlling the engine 22 and motor 30 in HV driving control, the HVECU 70 first sets a required torque Td* required for driving (required from the output shaft 42 of the transmission 40) based on the accelerator opening Acc and the vehicle speed V, and then sets a required torque Ti* for the input shaft 41 of the transmission 40 based on the set required torque Td* and the gear position M (gear ratio Gt) of the transmission 40. Next, the HVECU 70 sets a target torque Te* for the engine 22 and a torque command Tm* for the motor 30 so that the required torque Ti* is output to the input shaft 41. The HVECU 70 then transmits the target torque Te* for the engine 22 to the engine ECU 24, and transmits the torque command Tm* for the motor 30 to the motor ECU 34. The engine ECU 24 performs operation control (intake air amount control, fuel injection control, ignition control, etc.) of the engine 22 so that the engine 22 operates at the target torque Te*. The motor ECU 34 controls the switching of a plurality of switching elements of the inverter 32 so that the motor 30 is driven by the torque command Tm*.

[0029] In controlling the motor 30 in the EV driving mode, the HVECU 70 sets the required torque Ti* of the input shaft 41 in the same manner as in the HV driving mode, sets a torque command Tm* for the motor 30 so that the set required torque Ti* is output to the input shaft 41, and transmits the set torque command Tm* to the motor ECU 34. The control of the inverter 32 by the motor ECU 34 has been described above.

[0030] Next, the operation of the hybrid vehicle 20 of this embodiment configured as described above, particularly the operation when starting the engine 22 while the vehicle is traveling, will be described. Fig. 3 is a flowchart showing an example of a processing routine executed by the HVECU 70 when a start condition for the engine 22 is met while the vehicle is traveling. Here, the start condition for the engine 22 may be, for example, at least one of the following: an accelerator opening Acc is equal to or greater than a threshold value Aref; a vehicle speed V is equal to or greater than a threshold value Vref; a vehicle acceleration α is equal to or greater than a threshold value αref; a required torque Td* is equal to or greater than a threshold value Tdref; a power storage percentage SOC of the battery 50 is equal to or less than a threshold value Sref; and a running resistance Rr is equal to or greater than a threshold value Rrref.

[0031] When the processing routine of FIG. 3 is executed, the HVECU 70 first inputs data such as accelerator opening Acc, vehicle speed V, and vehicle acceleration α (step S100). Here, the accelerator opening Acc is inputted with a value detected by the accelerator pedal position sensor 84. The vehicle speed V is inputted with a value detected by the vehicle speed sensor 87. The vehicle acceleration α is inputted with a value detected by the acceleration sensor 88. Note that the vehicle acceleration α may be inputted with a value calculated as the amount of change in the vehicle speed V per unit time.

[0032] Once the data has been input in this manner, an upshift vehicle speed Vup, which is the vehicle speed on the upshift line of the transmission 40 at the current accelerator opening Acc, is set (step S110). This process can be performed by applying the current accelerator opening Acc to the shift line diagram of Fig. 2. For example, when the current gear position M is first gear, the vehicle speed V at the intersection of the current accelerator opening Acc and the upshift line from first gear to second gear on the shift line diagram of Fig. 2 is set as the upshift vehicle speed Vup.

[0033] Next, the current vehicle speed V is subtracted from the upshift vehicle speed Vup to calculate the vehicle speed difference ΔV (step S120), and the grace time Tgr until the start of an upshift of the transmission 40 is predicted based on the vehicle acceleration α and the vehicle speed difference ΔV (step S130). In the processing of step S130, when the vehicle acceleration α is positive, the vehicle speed difference ΔV is divided by the vehicle acceleration α to predict the grace time Tgr, and when the vehicle acceleration α is equal to or less than 0, the grace time Tgr is predicted to be longer than a threshold value Tgrref, which will be described later.

[0034] The predicted grace time Tgr is then compared with a threshold value Tgrref (step S140). Here, the threshold value Tgrref is a threshold value used to determine whether or not an upshift of the transmission 40 is expected to be performed in a relatively short time after the engine 22 has been started, and is, for example, about several seconds.

[0035] If the grace period Tgr is equal to or greater than the threshold value Tgrref in step S140, it is determined that an upshift of the transmission 40 is not expected to be performed relatively quickly after the start of the engine 22 is completed, and the start control of the engine 22 is executed (step S160), and this routine ends. Since the start condition of the engine 22 is satisfied while the vehicle is traveling in the EV driving mode, the motor 30 and the input shaft 41 of the transmission 40 are rotating. Based on this, in the start control of the engine 22, the HVECU 70 and the engine ECU 24 cooperatively control the clutch K0 to be in a slip engagement state, and increase the engagement force of the clutch K0 to increase the rotation speed Ne of the engine 22 (to approach the rotation speed Ni of the input shaft 41 of the transmission 40). When the rotation speed Ne of the engine 22 reaches or exceeds a predetermined rotation speed Nst, the fuel injection control and ignition control of the engine 22 are initiated, and the engagement force of the clutch K0 is further increased to fully engage the clutch K0, so that the rotation speed Ne of the engine 22 matches the rotation speed Ni of the input shaft 41 of the transmission 40.

[0036] If the grace period Tgr is less than the threshold value Tgrref in step S140, it is determined that an upshift of the transmission 40 is expected to be performed in a relatively short time after the start of the engine 22 is completed, and the routine waits for the sum of the grace period Tgr and the time Tgs required for the shift control (upshift) of the transmission 40 to elapse (step S150), then executes start control of the engine 22 (step S160), and ends this routine. Here, the time required for the shift control of the transmission 40 is a time determined in advance through experimentation or analysis.

[0037] In this way, by executing the start control of the engine 22 after the completion of the shift control (upshift) of the transmission 40, it is possible to prevent the transmission 40 from upshifting in a relatively short time after the completion of the start of the engine 22 (the increase in the rotation speed Ne of the engine 22 when starting the engine 22 and the decrease in the rotation speed Ne of the engine 22 accompanying the upshift of the transmission 40 occurring in a relatively short time). As a result, it is possible to prevent the driver from feeling uncomfortable. Furthermore, since the rotation speed Ni of the input shaft 41 (the rotation speed Nm of the motor 30) after the upshift of the transmission 40 is lower than the rotation speed Ni of the input shaft 41 before the upshift, by executing the start control of the engine 22 after the upshift is completed, it is possible to prevent the power used to increase the rotation speed Ne of the engine 22 from increasing, thereby preventing a decrease in driving force for traveling (deterioration of drivability), and it is also possible to prevent the amount of heat generated by the clutch K0 from increasing during the start control of the engine 22, thereby preventing a temperature rise of the clutch K0.

[0038] 4 is a time chart showing an example of the accelerator opening Acc, whether or not the start conditions for the engine 22 are met, the target gear M* and gear M of the transmission 40, the rotation speed Ne of the engine 22, the rotation speed Ni of the input shaft 41 of the transmission 40, and the temperature Tci of the clutch K0 in the example and the comparative example. In the comparative example, when the start conditions for the engine 22 are met, the start control of the engine 22 is executed regardless of the grace time Tgr.

[0039] As shown in the figure, in the comparative example, when a start condition for the engine 22 is met (time t11), start control for the engine 22 is executed. During the start control, if the gear position M of the transmission 40 differs from the target gear position M* and an upshift is requested (time t12), the gear shift control for the transmission 40 is executed after the start of the engine 22 is completed to avoid simultaneously executing the start control for the engine 22 and the gear shift control (upshift) of the transmission 40. Therefore, an increase in the rotation speed Ne of the engine 22 when starting the engine 22 and a decrease in the rotation speed Ne of the engine 22 accompanying the upshift of the transmission 40 occur in a relatively short period of time, which may cause a sense of discomfort to the driver. Furthermore, because the degree to which the rotation speed Ne of the engine 22 is increased in the start control for the engine 22 is relatively large, the power used to increase the rotation speed Ne of the engine 22 may increase, thereby reducing the driving force for traveling (deteriorating drivability), or the amount of heat generated by the clutch K0 during the start control of the engine 22 may increase, resulting in a significant temperature rise in the clutch K0. Furthermore, if the time between when an upshift of the transmission 40 is requested and when the upshift is actually executed (started) changes, the shift feeling given to the driver may change, or shift learning may not be performed properly.

[0040] In contrast, in this embodiment, when the start condition for the engine 22 is satisfied (time t11), if the grace period Tgr is less than the threshold value Tgrref, the start control for the engine 22 is suspended. Then, when an upshift of the transmission 40 is requested (time t12), the gear shift control is executed, and after the upshift is completed, the start control for the engine 22 is executed. This prevents the transmission 40 from being upshifted in a relatively short time after the start of the engine 22 is completed (the increase in the engine speed Ne of the engine 22 when starting the engine 22 and the decrease in the engine speed Ne associated with the upshift of the transmission 40 occur in a relatively short time), thereby preventing the driver from feeling uncomfortable. Furthermore, since the degree to which the engine speed Ne is increased in the start control for the engine 22 can be reduced, the power used to increase the engine speed Ne of the engine 22 can be prevented from increasing, thereby preventing a decrease in driving force for traveling (deterioration of drivability). Furthermore, the amount of heat generated by the clutch K0 during the start control of the engine 22 can be prevented from increasing, thereby preventing a large increase in the temperature of the clutch K0. Furthermore, since it is possible to suppress changes in the time from when an upshift of the transmission 40 is requested until the upshift is executed (started), it is possible to suppress changes in the shift feeling given to the driver and to perform shift learning more appropriately.

[0041] In the hybrid vehicle 20 of the embodiment described above, when a start condition for the engine 22 is met while the vehicle is traveling, if the grace period Tgr until the initiation of an upshift of the transmission 40 is equal to or greater than the threshold value Tgrref, the start control for the engine 22 is executed, and if the grace period Tgr is less than the threshold value Tgrref, the start control for the engine 22 is executed after the upshift of the transmission 40 is completed. This makes it possible to prevent the upshift of the transmission 40 from being executed in a relatively short time after the start of the engine 22 is completed. As a result, it is possible to prevent the increase and decrease in the rotation speed Ne of the engine 22 from occurring in a relatively short time, and to prevent the driver from feeling uncomfortable.

[0042] In the hybrid vehicle 20 of the embodiment, the target gear M* of the transmission 40 is set using the accelerator pedal position Acc, the vehicle speed V, and the shift diagram, and the gear M of the transmission 40 is compared with the target gear M* to determine whether an upshift of the transmission 40 is required. However, in addition to or instead of at least a part of the accelerator pedal position Acc and the vehicle speed V, the target gear M* may also be set using at least one of the required torque Td*, the vehicle acceleration α, the road gradient θr, and the running resistance Rr.

[0043] In the hybrid vehicle 20 of the embodiment, the grace time Tgr is predicted using the vehicle acceleration α and the vehicle speed difference ΔV. However, the grace time Tgr may be predicted based on only one of these. The grace time Tgr is predicted to be shorter as the vehicle acceleration α increases and longer as the vehicle speed difference ΔV increases. In addition to or instead of at least some of these, the grace time Tgr may be predicted using at least one of the accelerator pedal position Acc, the required torque Td*, the road surface gradient θr, and the running resistance Rr. The grace time Tgr is predicted to be shorter as the accelerator pedal position Acc increases, shorter as the required torque Td* increases, longer as the road surface gradient θr increases toward the uphill side, and longer as the running resistance Rr increases.

[0044] In the hybrid vehicle 20 of the embodiment, when a start condition for the engine 22 is met while the vehicle is traveling and the grace period Tgr is less than the threshold value Tgrref, the start control for the engine 22 is executed after waiting for the sum of the grace period Tgr and the time Tgs required for the shift control (upshift) of the transmission 40 to elapse. However, in this case, the start control for the engine 22 may be executed after waiting for the completion of the shift control of the transmission 40. Whether the shift control of the transmission 40 has been completed can be determined, for example, by checking the current value of a linear solenoid valve that supplies hydraulic pressure to an engagement-side element that switches from a disengaged state to an engaged state among the plurality of friction engagement elements.

[0045] In the hybrid vehicle 20 of the embodiment, the HVECU 70 executes the processing routine of Fig. 3. However, instead of this, the HVECU 70 may execute the processing routine of Fig. 5 or the processing routine of Fig. 6. These will be explained in order below.

[0046] The processing routine of Fig. 5 will be described. This routine is the same as the processing routine of Fig. 3 except that the processing of step S100 is replaced with the processing of step S200 and the processing of steps S210 to S230 has been added. Therefore, the same steps in the processing routine of Fig. 5 as those in the processing routine of Fig. 3 are assigned the same step numbers and detailed descriptions thereof will be omitted.

[0047] 5, the HVECU 70 inputs the accelerator pedal position Acc, vehicle speed V, and vehicle acceleration α as in the process of step S100, and also inputs the rotation speed Ni of the input shaft 41 of the transmission 40 detected by the rotation speed sensor 41a (step S200), and compares the input rotation speed Ni of the input shaft 41 of the transmission 40 with a threshold value Niref (step S210). Here, as the threshold value Niref, a rotation speed slightly lower than the lower limit of the rotation speed range of the input shaft 41 at which the clutch K0 is expected to become relatively hot when starting control of the engine 22 is executed is used. This is based on the fact that the amount of heat generated by the clutch K0 is likely to increase as the rotation speed Ni of the input shaft 41 increases when starting control of the engine 22 is executed.

[0048] If the rotation speed Ni of the input shaft 41 of the transmission 40 is equal to or greater than the threshold value Niref in step S210, the start control of the engine 22 is executed (step S160) regardless of the grace period Tgr, and this routine ends. This makes it possible to prevent the clutch K0 from becoming relatively hot when the start control of the engine 22 is executed.

[0049] If the rotation speed Ni of the input shaft 41 of the transmission 40 is less than the threshold value Niref in step S210, the processing from step S110 onwards is executed. Then, if the grace period Tgr is less than the threshold value Tgrref in step S140, the rotation speed Ni of the input shaft 41 of the transmission 40 is input (step S220) in the same way as in the processing of step S200, and the rotation speed Ni of the input shaft 41 is compared with the threshold value Niref (step S230) in the same way as in the processing of step S210.

[0050] When the rotation speed Ni of the input shaft 41 is less than the threshold value Niref, it is determined whether the sum of the grace time Tgr and the required time Tgs for the shift control (upshift) of the transmission 40 (Tgr+Tgs) has elapsed (step S150), and if this time (Tgr+Tgs) has not elapsed, the process returns to step S220. In this manner, the processes of steps S220, S230, and S150 are repeatedly executed, and if it is determined in step S150 that the time (Tgr+Tgs) has elapsed, start control of the engine 22 is executed (step S160), and this routine ends.

[0051] If the rotation speed Ni of the input shaft 41 is equal to or greater than the threshold value Niref in step S230, the start control of the engine 22 is executed (step S160) even if the time (Tgr+Tgs) has not yet elapsed, and the routine ends. That is, in this case, the start control of the engine 22 is executed without waiting for the upshift of the transmission 40 to be completed. This makes it possible to prevent the clutch K0 from becoming relatively hot when the start control of the engine 22 is executed.

[0052] Next, the processing routine of Fig. 6 will be described. This routine is the same as the processing routine of Fig. 3 except that the processing of step S150 is replaced by the processing of steps S300 to S320. Therefore, the same steps in the processing routine of Fig. 6 as those in the processing routine of Fig. 3 are assigned the same step numbers, and detailed descriptions thereof will be omitted.

[0053] 6, when the grace period Tgr is less than the threshold value Tgrref in step S140, the HVECU 70 waits for the grace period Tgr to elapse (step S300) and then determines whether or not an upshift of the transmission 40 is requested (including the case where shift control has already started) (step S310). If it is determined that an upshift of the transmission 40 is requested, the HVECU 70 waits for the required time Tgs for the shift control (upshift) of the transmission 40 to elapse (step S320), then executes start control of the engine 22 (step S160), and ends this routine. On the other hand, if it is determined that an upshift of the transmission 40 is not requested, the HVECU 70 executes start control of the engine 22 (step S160) without waiting for the required time Tgs to elapse, and ends this routine.

[0054] Here, an example of a case where an upshift of the transmission 40 is not requested when the grace time Tgr has elapsed is when, while waiting for the grace time Tgr to elapse, the vehicle acceleration α decreases because the road becomes an uphill road or the driver eases up on the accelerator pedal 83. In the modified example, in such a case, it is determined that there is a low possibility that an upshift of the transmission 40 will be performed in a relatively short time thereafter, and the start control of the engine 22 is executed without waiting for the upshift of the transmission 40.

[0055] The above description has been given of the case where the HVECU 70 executes the processing routine of Fig. 5 and the processing routine of Fig. 6. However, the HVECU 70 may execute a routine that combines these routines.

[0056] In the hybrid vehicle 20 of the embodiment, the transmission 40 is configured as a four-speed automatic transmission. However, the transmission 40 may be configured as a three-speed, five-speed, six-speed, or other automatic transmission.

[0057] In the hybrid vehicle 20 of the embodiment, a battery 50 is used as the power storage device. However, a capacitor may be used as the power storage device.

[0058] The hybrid vehicle 20 of the embodiment includes the engine ECU 24, the motor ECU 34, the transmission ECU 46, the battery ECU 52, and the HVECU 70. However, at least two of these may be integrated into one unit.

[0059] The correspondence between the main elements of the embodiment and the main elements of the invention described in the "Means for Solving the Problem" section will be explained below. In the embodiment, the engine 22 corresponds to the "engine," the motor 30 corresponds to the "motor," the clutch K0 corresponds to the "clutch," the transmission 40 corresponds to the "transmission," and the HVECU 70, the engine ECU 24, the motor ECU 34, and the transmission ECU 46 correspond to the "controller."

[0060] The correspondence between the main elements of the Examples and the main elements of the invention described in the "Means for Solving the Problem" section does not limit the elements of the invention described in the "Means for Solving the Problem" section, since the Examples are examples for specifically explaining the mode for implementing the invention described in the "Means for Solving the Problem" section. In other words, the interpretation of the invention described in the "Means for Solving the Problem" section should be based on the description in that section, and the Examples are merely specific examples of the invention described in the "Means for Solving the Problem" section.

[0061] The above describes the form for carrying out the present invention using examples, but the present invention is not limited to these examples in any way, and it goes without saying that the present invention can be carried out in various forms within the scope that does not deviate from the gist of the present invention. [Industrial Applicability]

[0062] The present invention can be used in the hybrid vehicle manufacturing industry and the like. [Explanation of symbols]

[0063] 20 hybrid vehicle, 22 engine, 23 crankshaft, 23a crank position sensor, 24 engine ECU, 30 motor, 30a rotational position sensor, 31 rotating shaft, 32 inverter, 34 motor ECU, K0, WSC clutch, 40 transmission, 41 input shaft, 41a rotation speed sensor, 42 output shaft, 42a rotation speed sensor, 44 hydraulic control device, 46 transmission ECU, 48 differential gear, 49 drive wheels, 50 battery, 52 battery ECU, 54 power line, 70 HVECU, 80 start switch, 81 shift lever, 82 shift position sensor, 83 accelerator pedal, 84 accelerator pedal position sensor, 85 brake pedal, 86 brake pedal position sensor, 87 vehicle speed sensor, 88 acceleration sensor, 89 gradient sensor.

Claims

1. an engine and a motor; a clutch provided between the engine and the motor; a transmission having an input shaft connected to the motor and an output shaft connected to drive wheels; a control device that executes start control to control the clutch and the engine so that, when starting the engine while the vehicle is running, the engine is started with an increase in engine speed due to slip engagement of the clutch; A hybrid vehicle comprising: The control device When the engine start condition is met while the vehicle is running, When the grace time until the start of the upshift of the transmission is equal to or longer than a predetermined time, the start control is executed. When the grace time is less than the predetermined time, the start control is executed after the upshift is completed. When the start condition is satisfied while the vehicle is running, if the upshift is not requested when the grace time that is less than the predetermined time has elapsed, the control device executes the start control without waiting for the upshift. Hybrid car.

2. The hybrid vehicle according to claim 1, When the start condition is satisfied while the vehicle is traveling, the control device predicts the grace time based on at least one of an accelerator operation amount, a vehicle speed, a vehicle acceleration, a required torque for traveling, a road surface gradient, and a traveling resistance. Hybrid car.

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