JP2006170265A - Automobile and method of controlling the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To rapidly accelerate after a vehicle speed is reduced in the stopped state of the operation of an engine. <P>SOLUTION: When the vehicle speed V is reduced lower than a threshold Vst (step S110) or a shift ratio R is lower than a reduction ratio Rth enabling sufficient acceleration (steps S120, S130) when the operation of the engine is stopped in the disengaged state of a clutch engaging the engine with a CVT, the target rotational speed Np* of the input shaft of the CVT is set so that the shift ratio of the CVT can be increased as a speed reduction ratio (step S140) and an electric oil pump generating a hydraulic pressure used to hydraulically control the CVT is driven to shift-control the CVT (step S150). Thus, since the shift ratio can be increased as the speed reduction ratio by shift-controlling the CVT even after the operation of the engine is stopped, the automobile can be rapidly accelerated after the vehicle speed is reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an automobile and a control method thereof.

2. Description of the Related Art Conventionally, as this type of automobile, an automobile including an oil pump that is driven using engine power and a continuously variable transmission that uses a hydraulic pressure generated by the oil pump has been proposed (for example, a patent). Reference 1). In this vehicle, when the engine and the continuously variable transmission are in a neutral state, the speed reduction ratio of the continuously variable transmission is controlled to be large, so that even when the vehicle stops in the neutral state and then starts quickly, It can be accelerated to.
JP-A-3-194251

  However, in the above-described automobile, the oil pump is driven using the power of the engine. Therefore, when the engine operation is stopped, the oil pump is not driven and the speed change by the continuously variable transmission cannot be performed. In such an automobile, when traveling with the engine stopped in the neutral state, the gear ratio may be maintained on the high speed side because the continuously variable transmission cannot be shifted after the engine is stopped. If the high gear ratio is maintained in this way, the engine is stopped and the vehicle is driven to accelerate quickly when the driver requests acceleration or when the vehicle stops and restarts. It becomes difficult to do. In order to avoid such a problem, it is conceivable to continue the operation of the engine. However, if the operation of the engine is continued, the fuel consumption is lowered and the efficiency of the entire system is lowered.

  One object of the automobile of the present invention is to accelerate quickly after the vehicle speed decreases while the operation of the internal combustion engine is stopped. Another object of the vehicle of the present invention is to improve the efficiency of the entire system.

  The automobile of the present invention has taken the following means in order to achieve at least a part of the above-mentioned object.

The first automobile of the present invention is
An internal combustion engine;
First fluid pressure generating means for generating a fluid pressure of the working fluid using the power of the internal combustion engine;
Second fluid pressure generating means for generating fluid pressure of the working fluid using electric power;
Transmission means capable of shifting the power of the input shaft with a change in the transmission gear ratio using the fluid pressure of the working fluid and outputting it to the drive shaft connected to the axle;
A connection release means for connecting and releasing the connection between the output shaft of the internal combustion engine and the input shaft;
Vehicle speed detection means for detecting the vehicle speed;
When the vehicle speed detected by the vehicle speed detecting means decreases to a predetermined vehicle speed while the operation of the internal combustion engine is stopped in a state where the connection by the connection releasing means is released, the fluid of the working fluid Control means for driving and controlling the second fluid pressure generating means so as to generate pressure, and for driving and controlling the speed changing means using the generated fluid pressure so that the speed ratio becomes equal to or greater than a predetermined reduction ratio;
It is a summary to provide.

  In the first automobile of the present invention, the vehicle speed detection means detects the operation of the internal combustion engine while the connection between the output shaft of the internal combustion engine and the input shaft of the transmission means is released by the connection release means. When the vehicle speed is reduced to a predetermined vehicle speed, the second fluid pressure generating means is driven and controlled so that the fluid pressure of the working fluid is generated, and the transmission ratio is equal to or greater than the predetermined reduction ratio using the generated fluid pressure. The transmission means is controlled to be driven. As a result, it is possible to accelerate quickly after the vehicle speed decreases to a predetermined vehicle speed while the operation of the internal combustion engine is stopped. Further, since the operation of the internal combustion engine is stopped until the vehicle speed detected by the vehicle speed detecting means decreases to reach a predetermined vehicle speed, the fuel efficiency can be improved and the efficiency of the entire system can be improved. Here, the “working fluid” includes hydraulic oil.

The second automobile of the present invention is
An internal combustion engine;
First fluid pressure generating means for generating a fluid pressure of the working fluid using the power of the internal combustion engine;
Transmission means capable of shifting the power of the input shaft with a change in the transmission gear ratio using the fluid pressure of the working fluid and outputting it to the drive shaft connected to the axle;
A connection release means for connecting and releasing the connection between the output shaft of the internal combustion engine and the input shaft;
Vehicle speed detection means for detecting the vehicle speed;
The internal combustion engine is started when the vehicle speed detected by the vehicle speed detection means decreases to a predetermined vehicle speed while the operation of the internal combustion engine is stopped in a state where the connection by the connection release means is released. And a control means for drivingly controlling the speed change means so that the speed ratio becomes equal to or greater than a predetermined speed reduction ratio using the fluid pressure of the working fluid generated by the first fluid generation means using the power from the internal combustion engine;
It is a summary to provide.

  In the second automobile of the present invention, when the vehicle speed detected by the vehicle speed detecting means decreases and reaches a predetermined vehicle speed while the operation of the internal combustion engine is stopped in a state where the connection by the connection releasing means is released. The internal combustion engine is started, and the transmission means is driven and controlled using the fluid pressure of the working fluid generated by the first fluid generation means using the power from the internal combustion engine so that the transmission gear ratio becomes equal to or greater than a predetermined reduction ratio. As a result, it is possible to accelerate quickly after the vehicle speed decreases to a predetermined vehicle speed while the operation of the internal combustion engine is stopped.

  In the first or second automobile of the present invention, the predetermined vehicle speed may be a vehicle speed at which the automobile is estimated to stop. If it carries out like this, after the stop of a motor vehicle is estimated, it can accelerate rapidly.

  In the first or second automobile of the present invention, the predetermined reduction ratio may be a reduction ratio sufficient for starting and accelerating the automobile among the transmission ratios changeable by the transmission means. it can. If it carries out like this, it can accelerate quickly at the time of start.

  In the first or second automobile of the present invention, the transmission means may be a belt type continuously variable transmission.

  The first or second automobile of the present invention includes an electric motor capable of outputting power to an axle different from the axle to which the speed change means is connected, and the control means is configured to release the connection when the connection by the connection release means is released. It may be a means for controlling the internal combustion engine and the electric motor so that the operation of the internal combustion engine is stopped and a braking force is applied by the electric motor. Since regenerative electric power is generated by controlling the electric motor so that the braking force is applied by the electric motor, the efficiency of the entire system can be further improved.

The first automobile control method of the present invention comprises:
An internal combustion engine; first fluid pressure generating means for generating a fluid pressure of the working fluid using power of the internal combustion engine; second fluid pressure generating means for generating a fluid pressure of the working fluid; and fluid of the working fluid A transmission means capable of shifting the power of the input shaft with a change of the transmission gear ratio using pressure and outputting it to the drive shaft connected to the axle, and connection and connection between the output shaft of the internal combustion engine and the input shaft; A connection release means for releasing the vehicle, comprising: a vehicle control method comprising:
When the vehicle speed decreases to a predetermined vehicle speed while the operation of the internal combustion engine is stopped in a state where the connection by the connection release means is released, the second pressure is generated so that the fluid pressure of the working fluid is generated. The gist of the invention is to drive and control the fluid pressure generating means and to drive and control the speed changing means using the generated fluid pressure so that the speed ratio becomes equal to or higher than a predetermined reduction ratio.

  In the first automobile control method of the present invention, when the vehicle speed decreases to a predetermined vehicle speed while the operation of the internal combustion engine is stopped in a state where the connection by the connection release means is released, the working fluid is The second fluid pressure generating means is driven and controlled so that the fluid pressure is generated, and the speed changing means is driven and controlled using the generated fluid pressure so that the gear ratio becomes equal to or greater than a predetermined reduction ratio. As a result, it is possible to accelerate quickly after the vehicle speed decreases to a predetermined vehicle speed while the operation of the internal combustion engine is stopped.

The second automobile control method of the present invention comprises:
An internal combustion engine, first fluid pressure generating means for generating a fluid pressure of the working fluid using the power of the internal combustion engine, and changing the speed ratio using the fluid pressure of the working fluid, shifting the power of the input shaft. And a connection release means for connecting and releasing the connection between the output shaft of the internal combustion engine and the input shaft. ,
When the vehicle speed decreases to a predetermined vehicle speed while the operation of the internal combustion engine is stopped in the state where the connection by the connection release means is released, the internal combustion engine is started and the power from the internal combustion engine is Using the fluid pressure of the working fluid generated by the first fluid generating means, the speed change means is driven and controlled so that the speed change ratio is equal to or greater than a predetermined reduction ratio.

  In the second automobile control method of the present invention, when the vehicle speed decreases to a predetermined vehicle speed while the operation of the internal combustion engine is stopped in a state where the connection by the connection release means is released, the internal combustion engine is The speed change means is driven and controlled using the fluid pressure of the working fluid generated by the first fluid generation means using the power from the internal combustion engine so that the speed ratio becomes equal to or greater than a predetermined reduction ratio. As a result, it is possible to accelerate quickly after the vehicle speed decreases to a predetermined vehicle speed while the operation of the internal combustion engine is stopped.

  Next, the best mode for carrying out the present invention will be described using examples.

  FIG. 1 is a configuration diagram showing an outline of the configuration of a hybrid vehicle 20 as an embodiment of the present invention. The hybrid vehicle 20 of the embodiment is a vehicle that can be driven by four-wheel drive, and outputs the power from the engine 22 to the front shaft 64 via the torque converter 25, the CVT 50, and the gear mechanism 65 to drive the front wheels 63a and 63b. A front wheel drive system for driving, a rear wheel drive system for driving the rear wheels 66a and 66b by outputting the power from the motor 40 to the rear shaft 67 via the gear mechanism 68, and a hybrid electronic control unit 70 for controlling the entire apparatus. With. In addition, the hybrid vehicle 20 includes a mechanical oil pump 26 that generates power of the CVT 50 using power from the engine 22, and an alternator 32 that generates power using power from the engine 22 via a DC / DC converter 34. And an electric oil pump 36 that generates line hydraulic pressure of the CVT 50 using supplied electric power. Further, the output shaft 27 of the torque converter 25 and the input shaft 51 of the CVT 50 are connected or disconnected by the clutch C1 as necessary. The electric oil pump 36 includes an electric motor (not shown), and the electric motor is driven and controlled by the hybrid electronic control unit 70.

  The engine 22 is an internal combustion engine that outputs power using hydrocarbon fuel such as gasoline or light oil. An alternator 32 and a mechanical oil pump 26 are attached to a crankshaft 23 of the engine 22 by a belt 24. Operation control of the engine 22, for example, fuel injection control, ignition control, intake air amount adjustment control, and the like are performed by an engine electronic control unit (hereinafter referred to as engine ECU) 29. The engine ECU 29 communicates with the hybrid electronic control unit 70, controls the operation of the engine 22 by a control signal from the hybrid electronic control unit 70, and, if necessary, transmits data related to the operating state of the engine 22 to the hybrid electronic control. Output to unit 70.

  The motor 40 is configured as a well-known synchronous generator motor that can be driven as a generator and can be driven as an electric motor. The motor 40 exchanges power with the high-voltage battery 31 via the inverter 41 or receives power from the alternator 32. . The motor 40 is driven and controlled by a motor electronic control unit (hereinafter referred to as a motor ECU) 42. Applied to the motor ECU 42 is a signal necessary for driving and controlling the motor 40, for example, a signal from a rotational position detection sensor 43 that detects the rotational position of the rotor of the motor 40, or a motor 40 detected by a current sensor (not shown). Phase current to be input. The motor ECU 42 communicates with the hybrid electronic control unit 70, and controls the drive of the motor 40 by outputting a switching control signal to the inverter 41 by a control signal from the hybrid electronic control unit 70, and if necessary. Data relating to the operating state of the motor 40 is output to the hybrid electronic control unit 70.

  The high voltage battery 31 is configured as a secondary battery having a rated voltage Vh (for example, 42 [V]), stores the power supplied from the alternator 32, and exchanges power with the motor 40. The low voltage battery 35 is configured as a secondary battery having a rated voltage Vl (for example, about 12 [V]) lower than the rated voltage Vh, and stores the power supplied from the alternator 32 via the DC / DC converter 34. In addition, power is supplied to devices operating at a low voltage such as an auxiliary machine (not shown). The DC / DC converter 34 is configured as a normal DC / DC converter that converts direct-current power into direct-current power of a different voltage, and converts the generated power from the alternator 32 to a low voltage as needed to convert the low-voltage battery 35. Or supplied to an electric motor (not shown) of the electric oil pump 36. The high voltage battery 31, the low voltage battery 35, and the DC / DC converter 34 are managed by a battery electronic control unit (hereinafter referred to as a battery ECU) 30. The battery ECU 30 receives signals necessary for managing the high voltage battery 31 and the low voltage battery 35, for example, the voltage between terminals of both batteries detected by a sensor (not shown), charge / discharge current, battery temperature, and the like. If necessary, data relating to the states of both batteries is output to the hybrid electronic control unit 70 by communication. Note that the battery ECU 30 also calculates the remaining capacity (SOC) based on the integrated value of the charge / discharge current in order to manage the high voltage battery 31 and the low voltage battery 35.

  The CVT 50 includes a primary pulley 53 that can be changed in groove width and connected to the input shaft 51, a secondary pulley 54 that is also changeable in groove width and connected to an output shaft 52 as a drive shaft, and a primary pulley 53 and a secondary pulley. 54, a belt 55, and a first actuator 56 and a second actuator 57 that change the groove widths of the primary pulley 53 and the secondary pulley 54. The primary actuator 53 and the second actuator 57 By changing the groove width of the secondary pulley 54, the power of the input shaft 51 is steplessly changed and output to the output shaft 52. Here, the first actuator 56 is used for controlling the transmission ratio, and the second actuator 57 is configured as a hydraulic actuator used for controlling the narrow pressure of the belt 55 for adjusting the transmission torque capacity of the CVT 50. .

  FIG. 2 is a configuration diagram showing an outline of the configuration of the speed change control mechanism 90 as the first actuator 56, and FIG. 3 is a configuration diagram showing an outline of the configuration of the belt narrow pressure control mechanism 95 as the second actuator 57. is there. As shown in FIG. 2, the shift control mechanism 90 includes duty solenoids 91 and 92 and shift control valves 93 and 94, and controls the shift control valve 93 by controlling the duty ratio of the duty solenoid 91. By adjusting the shift control valve 94 in the opening direction and adjusting the shift control valve 94 in the closing direction, the line oil pressure from the mechanical oil pump 26 or the electric oil pump 36 is applied to the primary pulley 53 to upshift the CVT 50, and the duty solenoid 92 The shift control valve 93 is adjusted in the closing direction by adjusting the duty ratio of the gear and the shift control 94 is adjusted in the opening direction so that the line hydraulic pressure acting on the primary pulley 53 is removed and the CVT 50 is downshifted. To be able to Going on. As shown in FIG. 3, the belt narrow pressure control mechanism 95 includes a control valve 96, a regulator 97, a control valve 98, and a linear solenoid 99, and controls the linear solenoid 99 from the control valve 96. By supplying the input hydraulic pressure to the regulator 97 and the control valve 98 and adjusting the opening and closing thereof, the line hydraulic pressure is adjusted, and the hydraulic pressure supplied to the secondary pulley 54 is adjusted so that the narrow pressure of the belt 55 can be adjusted. It has become.

  Shift control and belt narrow pressure control of the CVT 50 are performed by a CVT electronic control unit (hereinafter referred to as CVTECU) 59. The CVTECU 59 receives the rotational speed Np of the input shaft 51 from the rotational speed sensor 61 attached to the input shaft 51 and the rotational speed Ns of the output shaft 52 from the rotational speed sensor 62 attached to the output shaft 52. The CVTECU 59 outputs drive signals to the first actuator 56 (duty solenoids 91 and 92), the second actuator 57 (linear solenoid 99), and an electric motor (not shown) of the electric pump 36. The CVTECU 59 communicates with the hybrid electronic control unit 70, controls the transmission ratio of the CVT 50 by a control signal from the hybrid electronic control unit 70, and controls the input shaft 51 from the rotational speed sensor 61 as necessary. Data relating to the operating state of the CVT 50 such as the rotational speed Np and the rotational speed Ns of the output shaft 52 of the rotational speed sensor 62 is output to the hybrid electronic control unit 70. The CVT ECU 50 also controls the connection of the clutch C1.

  The hybrid electronic control unit 70 is configured as a microprocessor centered on the CPU 72, and in addition to the CPU 72, a ROM 74 for storing processing programs, a RAM 76 for temporarily storing data, an input / output port and communication not shown. And a port. The hybrid electronic control unit 70 includes an ignition signal from the ignition switch 80, a shift position SP from the shift position sensor 82 that detects the operation position of the shift lever 81, and an accelerator pedal position sensor that detects the amount of depression of the accelerator pedal 83. The accelerator opening Acc from 84, the brake pedal position BP from the brake pedal position sensor 86 for detecting the depression amount of the brake pedal 85, the vehicle speed V from the vehicle speed sensor 88, and the like are input via the input port. From the hybrid electronic control unit 70, a control signal to the alternator 32, a drive signal to an electric motor (not shown) of the electric oil pump 36, and the like are output via an output port. The hybrid electronic control unit 70 also exchanges various control signals and data with the engine ECU 29, the battery ECU 30, the motor ECU 42, and the CVTECU 59.

  The hybrid vehicle 20 of the embodiment thus configured mainly travels by outputting the power from the engine 22 to the front wheels according to the driver's accelerator operation, and outputs the power from the motor 40 to the rear wheels as necessary. And it runs by four-wheel drive. Examples of traveling by four-wheel drive include, for example, sudden acceleration when the accelerator pedal 83 is greatly depressed or when a wheel slips. Further, at the time of deceleration such as when the brake pedal 85 is depressed during traveling, the clutch C1 is disconnected, the engine 22 is disconnected from the CVT 50, the engine 22 is stopped, and the motor 40 is regeneratively controlled. Regenerative braking is used to apply braking force to the rear wheels 66a and 66b, and electric power regenerated from the motor 40 is stored in the high-voltage battery 31 to improve the efficiency of the entire system.

  Next, the operation of the hybrid vehicle 20 of the embodiment configured as described above, particularly the operation when the operation of the engine 22 is stopped in the state where the clutch C1 is disconnected will be described. FIG. 4 is a flowchart illustrating an example of an engine stop time control routine executed by the hybrid electronic control unit 70 of the embodiment. This routine is executed every predetermined time (for example, every several milliseconds) while the operation of the engine 22 is stopped in a state where the clutch C1 is disconnected.

  When the engine stop control routine is executed, the hybrid electronic control unit 70 first controls the vehicle speed V from the vehicle speed sensor 88, the rotation speed Np of the input shaft 51 of the CVT 50, the rotation speed Ns of the output shaft 52 of the CVT 50, and the like. A process of inputting necessary data is executed (step S100). Here, the rotational speed Np of the input shaft 51 of the CVT 50 and the rotational speed Ns of the output shaft 52 of the CVT 50 are those detected by the rotational speed sensors 61 and 62 and inputted from the CVTECU 59 to the hybrid electronic control unit 70. .

  Subsequently, whether or not the vehicle speed V is smaller than the vehicle speed threshold value Vst at which the hybrid vehicle 20 is estimated to stop (step S110), the vehicle speed Vpre that was input when this routine was executed last time, and the input at step S100. It is determined whether or not a deceleration ΔV (= Vpre−V) as a difference from the vehicle speed V is larger than a deceleration threshold ΔVth at which the stop of the hybrid vehicle 20 is estimated (step 160). When the vehicle speed V is smaller than the threshold value Vst, it is determined that the hybrid vehicle 20 is stopped, and the process proceeds to step S120. Also, when the deceleration ΔV is larger than the threshold value ΔVth, it is determined that the operator is requesting sudden braking, for example, the brake pedal 85 is depressed, and the process proceeds to step S120.

  Subsequently, a value obtained by dividing the rotation speed Np of the input shaft 51 of the CVT 50 by the rotation speed Ns of the output shaft 52 is calculated as a transmission gear ratio R (= Np / Ns) (step S120). It is determined whether or not it is smaller than a reduction ratio Rth that can be sufficiently accelerated when the vehicle starts after stopping 20 (step S130). Here, the reduction ratio Rth is set within a predetermined range (for example, 10%) from the largest reduction ratio within the range in which the CVT 50 can shift. If the speed ratio R is smaller than the speed reduction ratio Rth, it is determined that if the vehicle stops in this state, the vehicle cannot be sufficiently accelerated at the time of starting, and the vehicle speed V and a target rotational speed setting map stored in the ROM 74 in advance Based on the above, the target rotational speed Np * of the input shaft 51 is set so that the transmission gear ratio R becomes the largest reduction gear ratio among the transmission gear ratios of the CVT 50 (step S140). FIG. 5 shows an example of the target rotation speed setting map. In the drawing, a region surrounded by a solid line is a shift region in which the shift control of the CVT 50 is possible. In the present embodiment, when the vehicle speed V is given, the largest rotational speed among the rotational speeds corresponding to the vehicle speed V in the illustrated shift region is set as the target rotational speed Np *. In this way, the gear ratio of the CVT 50 can be set to the largest reduction ratio within a shiftable range.

  When the target rotational speed Np * is set, a drive request is transmitted to an electric motor (not shown) of the electric oil pump 36 to drive the electric oil pump 36, and the target rotational speed Np * is transmitted to the CVTECU 59 (step S150). End the routine. The CVTECU 59 that has received the target rotational speed Np * drives and controls the first actuator 56 (duty solenoids 91 and 92) so that the rotational speed of the input shaft 51 becomes the target rotational speed Np *. Thus, in the hybrid vehicle 20 of the embodiment, even when the engine 22 is stopped and the mechanical oil pump 26 is not driven, the electric oil pump 36 is driven to generate hydraulic pressure in the first actuator 56 and the transmission ratio of the CVT 50 is increased. Is controlled so as to have the largest reduction ratio with respect to the vehicle speed V, so that the vehicle can be restarted and re-accelerated quickly after the vehicle speed V decreases and the vehicle stops.

  On the other hand, it is determined that the vehicle speed V is equal to or higher than the vehicle speed threshold Vst at which the stop of the hybrid vehicle 20 is estimated (step S110), and the deceleration ΔV (= Vpre−V) is a decrease at which the stop of the hybrid vehicle 20 is estimated. When it is determined that the speed is equal to or less than the threshold value ΔVth (step S160), it is determined that the hybrid vehicle 20 does not stop. If the electric oil pump 36 is driven, the driving is stopped (step S170). finish. When the transmission gear ratio R is greater than the reduction gear ratio Rth (step S130), the electric oil pump 36 determines that the vehicle can be sufficiently accelerated at the start even if the transmission gear ratio is stopped in this state. If so, the drive is stopped (step S170), and this routine is terminated.

  According to the hybrid vehicle 20 of the embodiment described above, the vehicle speed V decreases to a vehicle speed Vst or less while the engine 22 is stopped with the clutch C1 disconnected and the engine 22 and CVT 50 disconnected. When this happens, the electric oil pump 36 is driven and the gear ratio R of the CVT 50 is controlled so as to be the largest reduction ratio with respect to the vehicle speed V. Can do. Further, when the clutch C1 is disconnected, the motor 40 is regeneratively controlled so that a braking force corresponding to the braking force applied by the engine brake is applied by the motor 40 when the clutch C1 is connected and the operation of the engine 22 is stopped. And since the regenerated electric power can be stored in the high voltage battery 31, the efficiency of the entire system can be improved.

  In the hybrid vehicle 20 of the embodiment, when the transmission gear ratio R is smaller than the predetermined transmission gear ratio Rth, the electric oil pump 36 is driven and hydraulic pressure is generated in the first actuator 56 to control the transmission of the CVT 50. In a hybrid vehicle that does not include the pump 36, the first actuator 56 may generate hydraulic pressure by starting the engine 22 and driving the mechanical oil pump 26. FIG. 6 shows an engine stop-time control routine executed by the hybrid electronic control unit 70 in the hybrid vehicle having no electric oil pump 36. In this engine stop time control routine, the same process as the engine stop time control routine shown in FIG. 4 is performed except for the processes in steps S150b and S170b. The description is omitted. In the engine stop time control routine, as shown in FIG. 6, when the vehicle speed V is smaller than the threshold value Vst or the deceleration ΔV is larger than the threshold value ΔVth (steps S110 and S160), the speed ratio R is smaller than the reduction ratio Rth (step S130). Then, the target rotational speed Np * of the input shaft 51 is set so that the transmission gear ratio R becomes the largest reduction gear ratio among the transmission gear ratios of the CVT 50 (step S140), and a start request for the engine 22 is transmitted to the engine ECU 29 and CVT ECU 59 The target rotation speed Np * is transmitted to (step S150b), and this routine is terminated. The CVTECU 59 that has received the target rotational speed Np * drives and controls the first actuator 56 (duty solenoids 91 and 92) so that the rotational speed of the input shaft 51 becomes the target rotational speed Np *, and receives the engine 22 start request. The engine ECU 29 performs start control for starting the engine 22. Note that the start control of the engine 22 includes control for operating the engine 22 such as ignition control and control for performing only cranking without performing control for operating the engine 22. On the other hand, when it is determined that the vehicle speed V is greater than or equal to the threshold value Vst (step S110), or when it is determined that the deceleration ΔV is less than or equal to the threshold value ΔVth (step S160), the speed ratio R is greater than or equal to the reduction ratio R. In some cases (step S130), if the engine 22 has been started, the engine 22 is stopped (step S170b), and this routine is terminated. As described above, even in a hybrid vehicle that does not include the electric oil pump 36, the mechanical oil pump 26 is driven by starting the engine 22 to generate hydraulic pressure in the first actuator 56 of the CVT 50, and the transmission ratio of the CVT 50 is high. By controlling the vehicle speed V so as to be the largest reduction ratio, it is possible to promptly restart and re-accelerate after the vehicle speed V decreases and the automobile stops.

  In the hybrid vehicle 20 of the embodiment, the target rotation speed Np * of the input shaft 51 of the CVT 50 is set so that the transmission ratio R of the CVT 50 becomes the largest reduction ratio among the transmission ratios that the CVT 50 can change. The ratio R may be a reduction ratio that is sufficient to quickly restart and re-accelerate after the vehicle stops, and the transmission ratio R is smaller than the largest reduction ratio among the transmission ratios that the CVT 50 can change. It is good also as what is set to.

  In the hybrid vehicle 20 of the embodiment, the belt-type CVT 50 is used as a continuously variable transmission. However, any transmission that can change the gear ratio using the fluid body pressure of a working fluid such as hydraulic oil may be used. CVT or a stepped transmission may be used.

  The best mode for carrying out the present invention has been described above by using the embodiments. However, the present invention is not limited to these embodiments, and can of course be implemented in various forms.

  The present invention is applicable to the automobile industry.

1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 as an embodiment of the present invention. 2 is a configuration diagram showing an outline of the configuration of a speed change control mechanism 90. FIG. 3 is a configuration diagram showing an outline of a configuration of a belt narrow pressure control mechanism 95. FIG. It is a flowchart which shows an example of the control routine at the time of an engine stop performed by the hybrid electronic control unit 70 of an Example. It is explanatory drawing which shows an example of the map for target rotation speed setting. An engine stop time control routine executed by a hybrid electronic control unit 70 in a hybrid vehicle having no electric oil pump 36 is shown.

Explanation of symbols

20 Hybrid Vehicle, 22 Engine, 23 Crankshaft, 24 Belt, 25 Torque Converter, 26 Mechanical Oil Pump, 27 Output Shaft, 30 Battery ECU, 31 High Voltage Battery, 32 Alternator, 34 DC / DC Converter, 35 Low Voltage Battery, 36 Electric oil pump, 40 motor, 41 inverter, 42 motor ECU, 43 rotational position detection sensor, 50 CVT, 51 input shaft, 52 output shaft, 53 primary pulley, 54 secondary pulley, 55 belt, 56 first actuator, 57 second Actuator, 59 CVT ECU, 61 RPM sensor, 62 RPM sensor, 63a, 63b Front wheel, 64 Front axle, 65, 68 Gear mechanism, 66a, 66b Rear wheel, 67 Rear axle, 70 Hybrid Electronic control unit, 72 CPU, 74 ROM, 76 RAM, 80 ignition switch, 81 shift lever, 82 shift position sensor, 83 accelerator pedal, 84 accelerator pedal position sensor, 85 brake pedal, 86 brake pedal position sensor, 88 vehicle speed Sensor, 90 shift control mechanism, 91, 92 duty solenoid, 93, 94 shift control valve, 96 control valve, 95 belt narrow pressure control mechanism, 96 control valve, 97 regulator, 98 control valve, C1 clutch.

Claims (8)

An internal combustion engine;
First fluid pressure generating means for generating a fluid pressure of the working fluid using the power of the internal combustion engine;
Second fluid pressure generating means for generating fluid pressure of the working fluid using electric power;
Transmission means capable of shifting the power of the input shaft with a change in the transmission gear ratio using the fluid pressure of the working fluid and outputting it to the drive shaft connected to the axle;
A connection release means for connecting and releasing the connection between the output shaft of the internal combustion engine and the input shaft;
Vehicle speed detection means for detecting the vehicle speed;
When the vehicle speed detected by the vehicle speed detecting means decreases to a predetermined vehicle speed while the operation of the internal combustion engine is stopped in a state where the connection by the connection releasing means is released, the fluid of the working fluid Control means for driving and controlling the second fluid pressure generating means so as to generate pressure, and for driving and controlling the speed changing means using the generated fluid pressure so that a gear ratio becomes equal to or greater than a predetermined reduction ratio;
Automobile equipped with. An internal combustion engine;
First fluid pressure generating means for generating a fluid pressure of the working fluid using the power of the internal combustion engine;
Transmission means capable of shifting the power of the input shaft with a change in the transmission gear ratio using the fluid pressure of the working fluid and outputting it to the drive shaft connected to the axle;
A connection release means for connecting and releasing the connection between the output shaft of the internal combustion engine and the input shaft;
Vehicle speed detection means for detecting the vehicle speed;
The internal combustion engine is started when the vehicle speed detected by the vehicle speed detection means decreases to a predetermined vehicle speed while the operation of the internal combustion engine is stopped in a state where the connection by the connection release means is released. And control means for driving and controlling the speed change means so that the speed ratio becomes equal to or greater than a predetermined speed reduction ratio using the fluid pressure of the working fluid generated by the first fluid generation means using the power from the internal combustion engine;
Automobile equipped with.   The automobile according to claim 1, wherein the predetermined vehicle speed is a vehicle speed at which the automobile is estimated to stop.   The automobile according to any one of claims 1 to 3, wherein the predetermined reduction ratio is a reduction ratio sufficient for the automobile to start and accelerate out of transmission ratios changeable by the transmission means.   The automobile according to any one of claims 1 to 4, wherein the transmission means is a belt type continuously variable transmission. The automobile according to any one of claims 1 to 5,
An electric motor capable of outputting power to an axle different from the axle to which the transmission means is coupled;
The control means is a means for controlling the internal combustion engine and the electric motor such that the operation of the internal combustion engine is stopped and a braking force is applied by the electric motor when the connection by the connection release means is released. An internal combustion engine; first fluid pressure generating means for generating a fluid pressure of the working fluid using power of the internal combustion engine; second fluid pressure generating means for generating a fluid pressure of the working fluid; and fluid of the working fluid A transmission means capable of shifting the power of the input shaft with a change of the transmission gear ratio using pressure and outputting it to the drive shaft connected to the axle, and connection and connection between the output shaft of the internal combustion engine and the input shaft; A connection release means for releasing the vehicle, comprising: a vehicle control method comprising:
When the vehicle speed decreases to a predetermined vehicle speed while the operation of the internal combustion engine is stopped in a state where the connection by the connection release means is released, the second pressure is generated so that the fluid pressure of the working fluid is generated. A method of controlling an automobile, wherein the fluid pressure generation means is driven and controlled, and the transmission means is driven and controlled so that the transmission ratio is equal to or greater than a predetermined reduction ratio using the generated fluid pressure. An internal combustion engine, first fluid pressure generating means for generating a fluid pressure of the working fluid using the power of the internal combustion engine, and changing the speed ratio using the fluid pressure of the working fluid, shifting the power of the input shaft. And a connection release means for connecting and releasing the connection between the output shaft of the internal combustion engine and the input shaft. ,
When the vehicle speed decreases to a predetermined vehicle speed while the operation of the internal combustion engine is stopped in the state where the connection by the connection release means is released, the internal combustion engine is started and the power from the internal combustion engine is A method of controlling an automobile in which the transmission means is driven and controlled so that the transmission gear ratio becomes equal to or greater than a predetermined reduction ratio using the fluid pressure of the working fluid generated by the first fluid generation means.

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