JP2007290613A - Vehicle and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce unburnt fuel contained in the exhaust gas of an engine in the case of motoring an engine. <P>SOLUTION: In the case of braking a vehicle, when the revolving speed Ne of an engine is a lower limit revolving speed Nref or lower, and a shift position SP is within a range for motoring the engine (steps S120, S140), the supply of fuel is immediately stopped (step S180), and the motoring of the engine is operated so that the revolving speed Ne of the engine reaches the revolving speed corresponding to a speed V (steps S190, S200). When the revolving speed Ne of the engine is a lower limit revolving speed Nref or lower, the supply of fuel is immediately stopped so that unburnt fuel contained in the exhaust gas of the engine is further reduced, to suppress the deterioration of a ternary catalyst owned by a purifying device for purifying the exhaust gas. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle and a control method thereof.

Conventionally, as this type of vehicle, there has been proposed a vehicle that includes an engine that outputs power to a drive shaft and that stops fuel supply to the engine to improve fuel efficiency during braking (see, for example, Patent Document 1). In this device, when the fuel supply to the engine is stopped, the fuel supply is stopped after the torque output from the engine is reduced in order to suppress the fluctuation of the torque. By shortening the time until the fuel supply is stopped as the engine load increases, misfire due to insufficient intake air amount in the intake system can be suppressed.
Japanese Patent Laid-Open No. 63-186941

  By the way, in this type of vehicle, there is a vehicle that motors the engine in order to use the engine brake as a braking force during braking. In such a vehicle, if the fuel supply to the engine is continued while the engine is motored during braking, the intake air amount of the intake system of the engine may be insufficient and misfire may occur. When misfire occurs in the engine, a lot of unburned fuel is contained in the exhaust gas of the engine, and the catalyst of the exhaust gas purification device that purifies the exhaust gas of the engine deteriorates. Therefore, it is desirable to reduce the amount of unburned fuel contained in the engine exhaust gas.

  An object of the vehicle and the control method thereof of the present invention is to reduce unburned fuel contained in the exhaust gas of the internal combustion engine when motoring the internal combustion engine.

  The vehicle and the control method thereof according to the present invention employ the following means in order to achieve the above-described object.

The vehicle of the present invention
An internal combustion engine;
Motoring means capable of motoring the internal combustion engine with torque output on an axle;
Braking force applying means capable of applying braking force to the vehicle;
Fuel that waits for a predetermined period of time after the rotational speed of the internal combustion engine reaches or exceeds a predetermined rotational speed when a non-motoring braking force is applied to the vehicle without motoring the internal combustion engine by the motoring means The internal combustion engine and the motoring means are controlled so that the internal combustion engine is operated at a speed lower than the predetermined rotational speed when the injection is stopped, and the vehicle is controlled with the motoring of the internal combustion engine by the motoring means. When the braking force with motoring for applying power is applied, the internal combustion engine is stopped by the motoring means with the stop of fuel injection that does not wait for the predetermined time after the rotational speed of the internal combustion engine reaches the predetermined rotational speed or more. Braking control means for controlling the internal combustion engine and the motoring means to be motored;
It is a summary to provide.

  In the vehicle of the present invention, when the non-motoring braking force is applied to apply braking force to the vehicle without motoring of the internal combustion engine by the motoring means, the rotational speed of the internal combustion engine reaches or exceeds a predetermined time. The internal combustion engine and the motoring means are controlled so that the internal combustion engine is operated at a speed less than a predetermined number of times with the stop of the fuel injection waiting for the progress, and the braking force is applied to the vehicle with the motoring of the internal combustion engine by the motoring means. The internal combustion engine is motored by the motoring means with the stop of fuel injection without waiting for the elapse of a predetermined time after the rotation speed of the internal combustion engine reaches a predetermined rotation speed or more when the braking force with motoring is applied. And motoring means. When applying the braking force with motoring, the fuel injection is stopped without waiting for the elapse of a predetermined time after the rotation speed of the internal combustion engine reaches the predetermined rotation speed or more, so that unburned fuel contained in the exhaust gas of the internal combustion engine is more Can be reduced.

  In such a vehicle according to the present invention, the braking time control means may be configured such that the internal combustion engine stops the fuel injection without waiting for the elapse of the predetermined time after the rotation speed of the internal combustion engine reaches the predetermined rotation speed or more. When controlling to be motored by the ring means, the internal combustion engine may be controlled to immediately stop fuel injection when the rotational speed of the internal combustion engine reaches or exceeds the predetermined rotational speed. . Since the fuel injection is stopped immediately when the rotational speed of the internal combustion engine reaches a predetermined rotational speed or more, unburned fuel contained in the exhaust gas can be further reduced.

  Further, in the vehicle of the present invention, a plurality of positions including a first position for operating the internal combustion engine at an idle speed during braking and a second position for operating the internal combustion engine at a speed corresponding to the vehicle speed during braking. Position setting means for setting a position, and the braking control means controls when the non-motoring braking force is applied when the first position is set by the position setting means during braking, and the position during braking. When the second position is set by the setting means, it may be a means for controlling when the braking force with motoring is applied. By so doing, when the second position is set by the position setting means, it is possible to reduce the amount of unburned fuel contained in the exhaust gas.

  The vehicle according to the present invention further includes an electric motor capable of inputting / outputting power to / from the axle, and the braking control means is a means for controlling the electric motor so that a braking force by the electric motor is applied to the axle. It can also be. If it carries out like this, the braking force by an electric motor can be provided to an axle.

  In the vehicle according to the present invention, the motoring means is connected to an output shaft of the internal combustion engine and a drive shaft connected to the axle, and includes the input / output of power and power to transmit power from the internal combustion engine. It is also possible to provide power power input / output means capable of outputting at least a part to the drive shaft. In this case, the electric power drive input / output means is connected to the three shafts of the output shaft of the internal combustion engine, the drive shaft and the third shaft, and is based on the power input / output to any two of the three shafts. It may be a means provided with a three-axis power input / output means for inputting / outputting power to the remaining shaft and a generator capable of inputting / outputting power to / from the third shaft.

The vehicle control method of the present invention includes:
A vehicle control method comprising: an internal combustion engine; motoring means capable of motoring the internal combustion engine with torque output to an axle; and braking force applying means capable of applying a braking force to the vehicle,
When the braking force is applied to the vehicle without motoring the internal combustion engine by the motoring means, the fuel injection is stopped after a predetermined time has elapsed after the rotation speed of the internal combustion engine reaches or exceeds the predetermined rotation speed. The internal combustion engine and the motoring means are controlled so that the internal combustion engine is operated at a speed less than the predetermined rotational speed, and the braking force is applied to the vehicle with motoring of the internal combustion engine by the motoring means. The internal combustion engine and the motoring means so that the internal combustion engine is motored by the motoring means with the stop of fuel injection without waiting for the elapse of the predetermined time after the rotational speed of the internal combustion engine reaches a predetermined rotational speed or more. The gist is to control the above.

  In the vehicle control method of the present invention, when the braking force is applied to the vehicle without motoring of the internal combustion engine by the motoring means, a predetermined time has elapsed after the rotation speed of the internal combustion engine reaches or exceeds the predetermined rotation speed. When the internal combustion engine and the motoring means are controlled so that the internal combustion engine is operated at a speed lower than a predetermined speed with the stop of fuel injection, and the braking force is applied to the vehicle with the motoring of the internal combustion engine by the motoring means. The internal combustion engine and the motoring means are controlled so that the internal combustion engine is motored by the motoring means with the stop of fuel injection that does not wait for the elapse of a predetermined time after the rotational speed of the internal combustion engine reaches a predetermined rotational speed or more. When a braking force is applied to the vehicle with motoring of the internal combustion engine by the motoring means, the fuel injection is stopped without waiting for the elapse of a predetermined time after the rotation speed of the internal combustion engine reaches a predetermined rotation speed or more. The amount of unburned fuel contained in the exhaust gas of the engine can be reduced.

  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 according to an embodiment of the present invention. As shown in the figure, the hybrid vehicle 20 of the embodiment includes an engine 22, a three-shaft power distribution / integration mechanism 30 connected to a crankshaft 26 as an output shaft of the engine 22 via a damper 28, and power distribution / integration. A motor MG1 capable of generating electricity connected to the mechanism 30, a reduction gear 35 attached to a ring gear shaft 32a as a drive shaft connected to the power distribution and integration mechanism 30, a motor MG2 connected to the reduction gear 35, And a hybrid electronic control unit 70 for controlling the entire power output apparatus.

  The engine 22 is configured as an internal combustion engine capable of outputting power using a hydrocarbon-based fuel such as gasoline or light oil, and the air purified by an air cleaner 122 is passed through a throttle valve 124 as shown in FIG. Inhaled and gasoline is injected from the fuel injection valve 126 to mix the sucked air and gasoline, and this mixture is sucked into the fuel chamber through the intake valve 128 and explosively burned by an electric spark from the spark plug 130. Thus, the reciprocating motion of the piston 132 pushed down by the energy is converted into the rotational motion of the crankshaft 23. Exhaust gas from the engine 22 is discharged to the outside air through a purification device (three-way catalyst) 134 that purifies harmful components such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx).

  The engine 22 is controlled by an engine electronic control unit (hereinafter referred to as an engine ECU) 24. The engine ECU 24 is configured as a microprocessor centered on the CPU 24a, and includes a ROM 24b that stores a processing program, a RAM 24c that temporarily stores data, an input / output port and a communication port (not shown), in addition to the CPU 24a. . The engine ECU 24 includes signals from various sensors that detect the state of the engine 22, a crank position from the crank position sensor 140 that detects the rotational position of the crankshaft 23, and a water temperature sensor 142 that detects the temperature of cooling water in the engine 22. From the cooling water temperature from the combustion chamber, the in-cylinder pressure Pin from the pressure sensor 143 installed in the combustion chamber, the intake valve 128 that performs intake and exhaust to the combustion chamber, and the cam position sensor 144 that detects the rotational position of the camshaft that opens and closes the exhaust valve Cam position, throttle position from throttle valve position sensor 146 for detecting the position of throttle valve 124, air flow meter signal AF from air flow meter 148 attached to the intake pipe, and temperature sensor also attached to the intake pipe Intake air temperature from 49, the air-fuel ratio AF from an air-fuel ratio sensor 135a, such as oxygen signal from an oxygen sensor 135b is input via the input port. The engine ECU 24 also integrates various control signals for driving the engine 22, such as a drive signal to the fuel injection valve 126, a drive signal to the throttle motor 136 that adjusts the position of the throttle valve 124, and an igniter. The control signal to the ignition coil 138 and the control signal to the variable valve timing mechanism 150 that can change the opening / closing timing of the intake valve 128 are output via the output port. The engine ECU 24 is in communication 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 outputs data related to the operation state of the engine 22 as necessary. .

  The power distribution and integration mechanism 30 includes an external gear sun gear 31, an internal gear ring gear 32 arranged concentrically with the sun gear 31, a plurality of pinion gears 33 that mesh with the sun gear 31 and mesh with the ring gear 32, A planetary gear mechanism is provided that includes a carrier 34 that holds a plurality of pinion gears 33 so as to rotate and revolve, and that performs differential action using the sun gear 31, the ring gear 32, and the carrier 34 as rotational elements. In the power distribution and integration mechanism 30, the crankshaft 26 of the engine 22 is connected to the carrier 34, the motor MG1 is connected to the sun gear 31, and the reduction gear 35 is connected to the ring gear 32 via the ring gear shaft 32a. When functioning as a generator, power from the engine 22 input from the carrier 34 is distributed according to the gear ratio between the sun gear 31 side and the ring gear 32 side, and when the motor MG1 functions as an electric motor, the engine input from the carrier 34 The power from 22 and the power from the motor MG1 input from the sun gear 31 are integrated and output to the ring gear 32 side. The power output to the ring gear 32 is finally output from the ring gear shaft 32a to the drive wheels 63a and 63b of the vehicle via the gear mechanism 60 and the differential gear 62.

  The motor MG1 and the motor MG2 are both configured as well-known synchronous generator motors that can be driven as generators and can be driven as motors, and exchange power with the battery 50 via inverters 41 and 42. The power line 54 connecting the inverters 41 and 42 and the battery 50 is configured as a positive electrode bus and a negative electrode bus shared by the inverters 41 and 42, and the electric power generated by one of the motors MG1 and MG2 It can be consumed by a motor. Therefore, battery 50 is charged / discharged by electric power generated from one of motors MG1 and MG2 or insufficient electric power. If the balance of electric power is balanced by the motors MG1 and MG2, the battery 50 is not charged / discharged. The motors MG1 and MG2 are both driven and controlled by a motor electronic control unit (hereinafter referred to as a motor ECU) 40. The motor ECU 40 detects signals necessary for driving and controlling the motors MG1 and MG2, such as signals from rotational position detection sensors 43 and 44 that detect the rotational positions of the rotors of the motors MG1 and MG2, and current sensors (not shown). The phase current applied to the motors MG1 and MG2 to be applied is input, and a switching control signal to the inverters 41 and 42 is output from the motor ECU 40. The motor ECU 40 is in communication with the hybrid electronic control unit 70, controls the driving of the motors MG1 and MG2 by a control signal from the hybrid electronic control unit 70, and, if necessary, data on the operating state of the motors MG1 and MG2. Output to the hybrid electronic control unit 70.

  The battery 50 is managed by a battery electronic control unit (hereinafter referred to as a battery ECU) 52. The battery ECU 52 receives signals necessary for managing the battery 50, for example, a voltage between terminals from a voltage sensor (not shown) installed between terminals of the battery 50, and a power line 54 connected to the output terminal of the battery 50. The charging / discharging current from the attached current sensor (not shown), the battery temperature Tb from the temperature sensor 51 attached to the battery 50, and the like are input. Output to the control unit 70. The battery ECU 52 also calculates the remaining capacity (SOC) based on the integrated value of the charge / discharge current detected by the current sensor in order to manage the battery 50.

  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 an ignition switch 80, a shift position SP from a shift position sensor 82 that detects the operation position of the shift lever 81, and an accelerator pedal position sensor 84 that detects the amount of depression of the accelerator pedal 83. The accelerator pedal opening Acc from the vehicle, 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. Here, the operation position of the shift lever 81 includes a normal drive range that travels in the forward direction (hereinafter referred to as the D range), a reverse range that travels backward, and a brake range that generates a braking force greater than the D range when the accelerator is off. There are a sequential shift range (hereinafter referred to as S range) in addition to a parking range used during parking (hereinafter referred to as B range), a neutral range and the like. The S range is set as a four-step or five-step sequential shift, and an upshift or a downshift is performed in accordance with the operation of the shift lever 81 by the driver, and the accelerator opening Acc is a predetermined opening (for example, 90%). ) In the above case, an upshift is performed based on the vehicle speed V regardless of whether or not the driver has operated the shift lever 81. When the accelerator opening degree Acc is less than a predetermined opening degree (for example, 10%), the driver Regardless of whether the shift lever 81 is operated or not, the vehicle is downshifted based on the vehicle speed V. As described above, the hybrid electronic control unit 70 is connected to the engine ECU 24, the motor ECU 40, and the battery ECU 52 via communication ports, and exchanges various control signals and data with the engine ECU 24, the motor ECU 40, and the battery ECU 52. Is doing.

  The hybrid vehicle 20 of the embodiment thus configured calculates the required torque to be output to the ring gear shaft 32a as the drive shaft based on the accelerator opening Acc and the vehicle speed V corresponding to the depression amount of the accelerator pedal 83 by the driver. Then, the operation of the engine 22, the motor MG1, and the motor MG2 is controlled so that the required power corresponding to the required torque is output to the ring gear shaft 32a. As operation control of the engine 22, the motor MG1, and the motor MG2, the operation of the engine 22 is controlled so that power corresponding to the required power is output from the engine 22, and all of the power output from the engine 22 is the power distribution and integration mechanism 30. Torque conversion operation mode for driving and controlling the motor MG1 and the motor MG2 so that the torque is converted by the motor MG1 and the motor MG2 and output to the ring gear shaft 32a, and the required power and the power required for charging and discharging the battery 50. The engine 22 is operated and controlled so that suitable power is output from the engine 22, and all or part of the power output from the engine 22 with charging / discharging of the battery 50 is the power distribution and integration mechanism 30, the motor MG1, and the motor. The required power is converted to the ring gear shaft 32 with torque conversion by MG2. Charge / discharge operation mode in which the motor MG1 and the motor MG2 are driven and controlled to be output to each other, and a motor operation mode in which the operation of the engine 22 is stopped and the power corresponding to the required power from the motor MG2 is output to the ring gear shaft 32a. and so on.

  Next, the operation of the hybrid vehicle 20 of the embodiment thus configured, particularly the operation at the time of braking such as when the accelerator is off, will be described. FIG. 3 is a flowchart showing an example of a braking drive control routine executed by the hybrid electronic control unit 70. This routine is repeatedly executed at predetermined time intervals (for example, every several milliseconds) during braking such as when the accelerator is off.

  When the braking drive control routine is executed, first, the CPU 72 of the hybrid electronic control unit 70 first determines the accelerator opening Acc from the accelerator pedal position sensor 84, the vehicle speed V from the vehicle speed sensor 88, and the rotational speed Ne of the engine 22. , Motor MG1, MG2 rotation speed Nm1, Nm2 battery 50 input limit Win, shift position sensor 82 shift position SP, brake pedal position sensor 86 brake pedal position BP, etc. Is executed (step S100). Here, the rotation speed Ne of the engine 22 is calculated based on a signal from a crank position sensor (not shown) attached to the crankshaft 26 and is input from the engine ECU 24 by communication. Further, the rotational speeds Nm1 and Nm2 of the motors MG1 and MG2 are input from the motor ECU 40 by communication from those calculated based on the rotational positions of the rotors of the motors MG1 and MG2 detected by the rotational position detection sensors 43 and 44. It was supposed to be. Further, the input limit Win of the battery 50 is set based on the battery temperature Tb of the battery 50 detected by the temperature sensor 51 and the remaining capacity (SOC) of the battery 50 and is input from the battery ECU 52 by communication. did.

  When the data is input in this way, the braking torque required for the vehicle is output to the ring gear shaft 32a as the driving shaft connected to the driving wheels 63a and 63b based on the accelerator opening Acc, the brake pedal position BP, and the vehicle speed V. The required braking torque Tr * to be set is set (step S110). In the embodiment, the required braking torque Tr * is stored in the ROM 74 as a required braking torque setting map by predetermining the relationship between the accelerator opening Acc, the brake pedal 85, the vehicle speed V, and the required braking torque Tr *. When the opening degree Acc, the brake position, and the vehicle speed V are given, the corresponding required torque Tr * is derived and set from the stored map. FIG. 4 shows an example of the required braking torque setting map.

  Subsequently, in order to suppress an excessive increase in the rotational speed of the engine 22, the lower limit rotational speed Nref (for example, 1700 rpm) as the lower limit value of the rotational speed at which the fuel supply to the engine 22 is stopped is input. It is determined whether or not it is equal to or higher than the rotation speed Ne (step S120). When the rotational speed Ne of the engine 22 is less than the lower limit rotational speed Nref, it is determined that the rotational speed Ne of the engine 22 does not increase excessively, and an instruction is given to the engine ECU 24 to idle the engine 22 (step S130). A value 0 is set in the torque command Tm1 * of the motor MG1 (step S170). Here, the instruction for the idle operation is specifically set by setting the target rotational speed Ne * of the engine 22 to the idle rotational speed Nidl (for example, 1200 rpm) and the target torque Te * to a value 0. The engine ECU 24 receives the target rotational speed Ne * and the target torque Te *. The engine ECU 24 receives the target rotational speed Ne * and the target torque Te * at an operating point indicated by the target rotational speed Ne * and the target torque Te *. Control such as fuel injection control and ignition control in the engine 22 is performed so as to be operated. FIG. 5 shows an example of a collinear diagram for dynamically explaining the rotational elements of the power distribution and integration mechanism 30 when the engine 22 is idling at the idling speed Nidl. In the figure, the left S-axis indicates the rotation speed of the sun gear 31 that is the rotation speed Nm1 of the motor MG1, the C-axis indicates the rotation speed of the carrier 34 that is the rotation speed Ne of the engine 22, and the R-axis indicates the rotation speed of the motor MG2. The rotational speed Nr of the ring gear 32 obtained by dividing the number Nm2 by the gear ratio Gr of the reduction gear 35 is shown. Two arrows on the C-axis indicate a torque Te output from the engine 22 to maintain the rotation of the engine 22 and a torque acting due to sliding friction or compression work caused by the rotation of the engine 22. An arrow on the R axis indicates torque output from the motor MG2 to the ring gear shaft 32a via the reduction gear 35.

  Thus, when the torque command Tm1 * of the motor MG1 is set, the power consumption of the motor MG1 obtained by multiplying the input limit Win of the battery 50 and the set torque command Tm1 * of the motor MG1 by the current rotation speed Nm1 of the motor MG1. A torque limit Tmin as a lower limit of the torque that may be output from the motor MG2 by dividing the deviation from (generated power) by the rotation speed Nm2 of the motor MG2 is calculated by the following equation (1) (step S210) and requested Using the torque Tr *, the torque command Tm1 *, and the gear ratio ρ of the power distribution and integration mechanism 30, a temporary motor torque Tm2tmp as a torque to be output from the motor MG2 is calculated by the equation (2) (step S220). The torque finger of the motor MG2 as a value obtained by limiting the temporary motor torque Tm2tmp with the limit Tmin Setting the Tm2 * (step S230). By setting the torque command Tm2 * of the motor MG2 in this manner, the required braking torque Tr * output to the ring gear shaft 32a as the drive shaft can be set as a torque limited by the input limit Win of the battery 50. Equation (2) can be easily derived from the collinear diagram of FIG. 5 described above.

Tmin = (Win-Tm1 * ・ Nm1) / Nm2 (1)
Tm2tmp = (Tr * + Tm1 * / ρ) / Gr (2)

  When the torque commands Tm1 * and Tm2 * for the motors MG1 and MG2 are thus set, the torque commands Tm1 * and Tm2 * are transmitted to the motor ECU 40 (step S240), and the braking drive control routine is terminated. Receiving the torque commands Tm1 * and Tm2 *, the motor ECU 40 controls the switching elements of the inverters 41 and 42 so that the motor MG1 is driven by the torque command Tm1 * and the motor MG2 is driven by the torque command Tm2 *. . As described above, when the rotational speed Ne of the engine 22 is less than the lower limit rotational speed Nref, the motors MG1 and MG2 are driven so that the required braking torque Tr * acts on the ring gear shaft 32a while the engine 22 is idling.

  On the other hand, when the rotational speed Ne of the engine 22 is equal to or higher than the lower limit rotational speed Nref, it is determined that the rotational speed Ne of the engine 22 may increase excessively, and then the shift position SP is determined (step S140). ). Since the accelerator is off during traveling, the shift position SP is any one of the D range, S range, and B range. When the shift position SP is in the D range, the rotational speed of the engine 22 is determined. The idle operation is instructed to continue the operation of the engine 22 for a time tref after Ne becomes equal to or higher than the lower limit rotational speed Nref (steps S150 and S130), and a value 0 is set to the torque command Tm1 * of the motor MG1. (Step S170), when the rotational speed Ne of the engine 22 does not become less than the lower limit rotational speed Nref during the time tref after the rotational speed Ne of the engine 22 becomes equal to or higher than the lower limit rotational speed Nref, the rotational speed Ne of the engine 22 is decreased. In order to perform a fuel cut that temporarily stops the supply of fuel to the engine 22. It instructs the emission ECU 24 (step S150, S160) sets the torque command Tm1 * to the value 0 of the motor MG1 (step S170). The reason why the fuel cut is executed after the elapse of time tref after the rotation speed Ne of the engine 22 becomes equal to or higher than the lower limit rotation speed Nref is as follows. FIG. 6 shows an example of a collinear diagram for dynamically explaining the rotating elements of the power distribution and integration mechanism 30 when the fuel cut of the engine 22 is being executed. As described above, by executing the fuel cut of the engine 22, the rotational speed Ne of the engine 22 decreases, but even if the rotational speed Ne exceeds the lower limit rotational speed Nref, the rotational speed Ne of the engine 22 immediately becomes the lower limit rotational speed Nref. Therefore, the fuel cut and idling operation of the engine 22, that is, the supply of fuel to the engine 22 is frequently resumed, and the torque shock accompanying the fuel cut frequently occurs and the driver gets on. You may feel uncomfortable. Thus, in order to suppress frequent occurrence of torque shock, the fuel cut is executed after the elapse of time tref after the rotation speed Ne of the engine 22 exceeds the lower limit rotation speed Nref. Therefore, the time tref is set as a time that allows it to be determined that if the fuel cut is not executed after the rotation speed Ne of the engine 22 becomes equal to or higher than the lower limit rotation speed Nref, the engine speed cannot be less than the lower limit rotation speed Nref. As described above, when the shift position SP is not in the B range or the S range, the fuel supply to the engine 22 is stopped after the time tref elapses after the rotation speed Ne of the engine 22 exceeds the lower limit rotation speed Nref. Thus, torque shock due to frequent occurrence of fuel supply or supply stoppage in a short time can be suppressed, and the driver can be prevented from feeling poor riding comfort.

  When the torque command Tm1 * of the motor MG1 is thus set, the torque limit Tmin is calculated using the torque command Tm1 * and the temporary motor torque Tm2tmp is calculated, and the temporary motor torque Tm2tmp is limited by the calculated torque limit Tmin. The torque command Tm2 * of the motor MG2 is set as a value, the set torque commands Tm1 * and Tm2 * are transmitted to the motor ECU 40, and this routine is finished (steps S210 to S240). Thus, when the shift position SP of the engine 22 is not in the B range or the S range, the regenerative braking force by the motor MG2 can be applied to the ring gear shaft 32a as the drive shaft while the engine 22 is idling, so that the required braking torque A braking force based on Tr * can be applied to the vehicle and energy efficiency can be improved.

  On the other hand, when the shift position SP is in the B range or S range (step S150), that is, in order to generate a braking force larger than the D range or to downshift according to the vehicle speed during braking, it is necessary to motor the engine 22. If there is, the fuel cut command is immediately transmitted to the engine ECU 24 (step S180), and the target rotational speed Ne * of the engine 22 is set to the rotational speed based on the vehicle speed V and the shift position SP (step S190). Here, the target rotational speed Ne * of the engine 22 is set to a relatively high rotational speed so that when the shift position SP is in the B range, a braking force is applied by the engine brake and a larger braking force is generated than in the D range. When the shift position SP is in the S range, a relatively high rotational speed is set so as to shift down based on the vehicle speed V.

  When the target rotational speed Ne * of the engine 22 is set in this way, the target rotational speed Ne * set so that the engine 22 is operated at the target rotational speed Ne *, the rotational speed Nr (Nm2 / Gr) of the ring gear shaft 32a, and power distribution integration. The target rotational speed Nm1 * of the motor MG1 is calculated by the following formula (3) using the gear ratio ρ of the mechanism 30 and the formula (4) based on the calculated target rotational speed Nm1 * and the current rotational speed Nm1. Torque command Tm1 * of motor MG1 is calculated (step S200). FIG. 7 shows an example of a collinear diagram for dynamically explaining the rotational elements of the power distribution and integration mechanism 30 when the engine 22 is operated at the target rotational speed Ne *. Expression (3) can be easily derived by using this alignment chart. Expression (4) is a relational expression in feedback control for rotating the motor MG1 at the target rotational speed Nm1 *. In Expression (2), “k1” in the second term on the right side is a gain of the proportional term. “K2” in the third term on the right side is the gain of the integral term.

Nm1 * = Ne * ・ (1 + ρ) / ρ-Nm2 / (Gr ・ ρ) (3)
Tm1 * = previous Tm1 * + k1 (Nm1 * -Nm1) + k2∫ (Nm1 * -Nm1) dt (4)

  Thus, when the torque command Tm1 * of the motor MG1 is set, the torque limit Tmin is calculated, the temporary motor torque Tm2tmp is calculated, and the torque command Tm2 of the motor MG2 is set as a value obtained by limiting the temporary motor torque Tm2tmp with the torque limit Tmin. * Is set and the set torque commands Tm1 * and Tm2 * are transmitted to the motor ECU 40, and this routine is finished (steps S210 to S240). Thus, when the rotational speed Ne of the engine 22 is equal to or higher than the lower limit rotational speed Nref and the shift position SP is in the B range or S range, the rotational speed Ne of the engine 22 becomes a rotational speed corresponding to the vehicle speed V. The motor MG1 controls the engine 22 and the required braking torque Tr * controls the motors MG1 and MG2 acting on the ring gear shaft 32a as the drive shaft. When the rotational speed Ne of the engine 22 becomes equal to or higher than the lower limit rotational speed Nref, the supply of fuel is immediately stopped and the engine 22 is motored, so that less unburned fuel is contained in the exhaust gas of the engine 22 It is possible to suppress the deterioration of the three-way catalyst that the purification device 134 has. In addition, since the engine 22 is motored together with the braking force by the motor MG2, the braking force by the engine brake can be applied, so that a larger braking force can be applied to the vehicle and the energy efficiency is improved. Can do. Of course, a braking force based on the required braking torque Tr * can be applied to the vehicle.

  In the hybrid vehicle 20 of the embodiment described above, if the shift position SP is in the B range or S range when the rotational speed Ne of the engine 22 is equal to or higher than the lower limit rotational speed Nref, the fuel supply is immediately stopped and the engine is stopped. The motor MG1 motorizes the engine 22 so that the rotational speed Ne of the motor 22 corresponds to the vehicle speed V, and the motors MG1 and MG2 are driven so that the required braking torque Tr * acts on the ring gear shaft 32a as the drive shaft. . When the rotational speed Ne of the engine 22 exceeds the lower limit rotational speed Nref, the fuel supply is immediately stopped and the engine 22 is motored, so that the amount of unburned fuel contained in the exhaust gas of the engine 22 is reduced. It is possible to suppress the deterioration of the three-way catalyst that the purification device 134 has. Further, since the braking force by the engine brake can be applied by motoring the engine 22 together with the braking force by the motor MG2, a larger braking force can be applied to the vehicle and energy efficiency can be improved. it can. Of course, the braking force based on the required braking torque Tr * can be applied to the ring gear shaft 32a as the drive shaft.

  In the hybrid vehicle 20 of the embodiment, when the rotational speed Ne of the engine 22 is equal to or higher than the lower limit rotational speed Nref, the fuel supply of the engine 22 is immediately stopped when the shift position SP is in the B range or the S range. If the fuel contained in the exhaust gas is allowed to slightly increase, the engine 22 waits for a time shorter than the time tref after the rotation speed Ne of the engine 22 becomes equal to or higher than the lower limit rotation speed Nref. The supply of fuel may be stopped without waiting for progress.

  In the hybrid vehicle 20 of the embodiment, the engine 22 is operated at the idling speed at the time of braking according to the shift position SP or the engine 22 is operated at the speed corresponding to the vehicle speed. However, the engine is operated according to the shift position SP. 22 is not limited to changing the driving method. For example, when a large braking force is not required, for example, when the accelerator pedal 83 is turned off and braking is performed, the engine 22 is operated at idle rotation. When a greater braking force is required, such as when 85 is depressed by a relatively large amount, the engine 22 is driven at a rotational speed corresponding to the vehicle speed and the engine 22 is motored to control the braking force by the engine brake and the motor MG2. It is good also as what brakes using motive power.

  In the hybrid vehicle 20 of the embodiment, the operation position of the shift lever 81 has the S range, but may have no S range.

  In the hybrid vehicle 20 of the embodiment, the braking force by the motor MG2, or the braking force by the motor MG2 and the braking force by the engine brake of the engine 22 are applied to the axle connected to the ring gear shaft 32a. In addition to the motor MG2, a means for applying a braking force to the axle may be provided. For example, the braking force is applied to the axle by a hydraulic brake (not shown) that applies the braking force to the driving wheels 63a and 63b and the driven wheel. Also good.

  In the hybrid vehicle 20 of the embodiment, the power of the motor MG2 is shifted by the reduction gear 35 and output to the ring gear shaft 32a. However, as illustrated in the hybrid vehicle 120 of the modified example of FIG. May be connected to an axle (an axle connected to the wheels 64a and 64b in FIG. 8) different from an axle to which the ring gear shaft 32a is connected (an axle to which the drive wheels 63a and 63b are connected).

  In the hybrid vehicle 20 of the embodiment, the power of the engine 22 is output to the ring gear shaft 32a as the drive shaft connected to the drive wheels 63a and 63b via the power distribution and integration mechanism 30, but the modified example of FIG. The hybrid vehicle 220 includes an inner rotor 232 connected to the crankshaft 26 of the engine 22 and an outer rotor 234 connected to a drive shaft that outputs power to the drive wheels 63a and 63b. A counter-rotor motor 230 that transmits a part of the power to the drive shaft and converts the remaining power into electric power may be provided.

  Moreover, it is not limited to what is applied to such a hybrid vehicle, It is good also as a form mounted in vehicles other than a motor vehicle. Furthermore, it is good also as a form of the control method of such a vehicle.

  The embodiments of the present invention have been described using the embodiments. However, the present invention is not limited to these embodiments, and can be implemented in various forms without departing from the gist of the present invention. Of course you get.

  The present invention can be used in the vehicle manufacturing industry.

1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 according to an embodiment of the present invention. 2 is a configuration diagram showing an outline of the configuration of an engine 22. FIG. It is a flowchart which shows an example of the control routine at the time of a braking performed by the electronic control unit for hybrids 70 of an Example. It is explanatory drawing which shows an example of the map for request | requirement braking torque setting. It is explanatory drawing which shows an example of the alignment chart for demonstrating dynamically the rotational element of the power distribution integration mechanism 30 when the engine 22 is idling. FIG. 3 is an explanatory diagram showing an example of a collinear diagram for dynamically explaining rotational elements of a power distribution and integration mechanism 30 when supply of fuel to an engine 22 is stopped. It is explanatory drawing which shows an example of the collinear diagram for demonstrating dynamically the rotational element of the power distribution integration mechanism 30 when the motor 22 is motored. FIG. 11 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 120 according to a modification. FIG. 11 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 220 of a modified example.

Explanation of symbols

20, 120, 220 Hybrid vehicle, 22 engine, 24 engine electronic control unit (engine ECU), 24a CPU, 24b ROM, 24c RAM, 26 crankshaft, 28 damper, 30 power distribution integration mechanism, 31 sun gear, 32 ring gear, 32a ring gear shaft, 33 pinion gear, 34 carrier, 35 reduction gear, 40 motor electronic control unit (motor ECU), 41, 42 inverter, 43, 44 rotational position detection sensor, 50 battery, 51 temperature sensor, 52 battery electronic control Unit (battery ECU), 54 power line, 60 gear mechanism, 62 differential gear, 63a, 63b driving wheel, 64a, 64b wheel, 70 hybrid electronic control unit, 72 CPU, 74 ROM, 76 RAM, 0 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, 122 Air cleaner, 124 Throttle valve, 126 Fuel injection valve, 128 Intake valve, 130 Spark plug, 132 Piston, 134 Purifier, 136, Throttle motor, 138 Ignition coil, 140 Crank position sensor, 142 Water temperature sensor, 143 Pressure sensor, 144 Cam position sensor, 146 Throttle valve position sensor, 148 Air flow meter 149 Temperature sensor, 150 Variable valve timing mechanism. 230 Counter rotor motor, 232 Inner rotor 234 Outer rotor, MG1, MG2 motor.

Claims (7)

An internal combustion engine;
Motoring means capable of motoring the internal combustion engine with torque output on an axle;
Braking force applying means capable of applying braking force to the vehicle;
Fuel that waits for a predetermined period of time after the rotational speed of the internal combustion engine reaches or exceeds a predetermined rotational speed when a non-motoring braking force is applied to the vehicle without motoring the internal combustion engine by the motoring means The internal combustion engine and the motoring means are controlled so that the internal combustion engine is operated at a speed lower than the predetermined rotational speed when the injection is stopped, and the vehicle is controlled with the motoring of the internal combustion engine by the motoring means. When the braking force with motoring for applying power is applied, the internal combustion engine is stopped by the motoring means with the stop of fuel injection that does not wait for the predetermined time after the rotational speed of the internal combustion engine reaches the predetermined rotational speed or more. Braking control means for controlling the internal combustion engine and the motoring means to be motored;
A vehicle comprising:   The braking time control means is configured such that the internal combustion engine is motored by the motoring means together with the stop of fuel injection without waiting for the elapse of the predetermined time after the rotation speed of the internal combustion engine reaches the predetermined rotation speed or more. 2. The vehicle according to claim 1, wherein the control unit controls the internal combustion engine to immediately stop fuel injection when the rotational speed of the internal combustion engine reaches or exceeds the predetermined rotational speed. The vehicle according to claim 1 or 2,
Position setting means for setting a plurality of positions including a first position for operating the internal combustion engine at an idle speed during braking and a second position for operating the internal combustion engine at a speed according to the vehicle speed during braking; Prepared,
The braking control means controls when the non-motoring braking force is applied when the first position is set by the position setting means during braking, and the second position is set by the position setting means during braking. It is means for controlling when the braking force with motoring is applied when
vehicle. A vehicle according to any one of claims 1 to 3,
An electric motor capable of inputting and outputting power to the axle;
The braking time control means is means for controlling the electric motor so that a braking force by the electric motor is applied to the axle.   The motoring means is connected to an output shaft of the internal combustion engine and a drive shaft connected to the axle, and at least part of the power from the internal combustion engine is input to the drive shaft with input and output of electric power and power. The vehicle according to any one of claims 1 to 4, further comprising an output power power input / output means.   The power power input / output means is connected to the three shafts of the output shaft, the drive shaft, and the third shaft of the internal combustion engine, and the remaining shaft based on the power input / output to any two of the three shafts. 6. The vehicle according to claim 5, further comprising: a three-axis power input / output means for inputting / outputting power to / from the power generator; A vehicle control method comprising: an internal combustion engine; motoring means capable of motoring the internal combustion engine with torque output to an axle; and braking force applying means capable of applying a braking force to the vehicle,
When the braking force is applied to the vehicle without motoring the internal combustion engine by the motoring means, the fuel injection is stopped after a predetermined time has elapsed after the rotation speed of the internal combustion engine reaches or exceeds the predetermined rotation speed. The internal combustion engine and the motoring means are controlled so that the internal combustion engine is operated at a speed less than the predetermined rotational speed, and the braking force is applied to the vehicle with motoring of the internal combustion engine by the motoring means. The internal combustion engine and the motoring means so that the internal combustion engine is motored by the motoring means with the stop of fuel injection without waiting for the elapse of the predetermined time after the rotational speed of the internal combustion engine reaches a predetermined rotational speed or more. And control the
A method for controlling a vehicle.

Images