JP2010202137A - Hybrid vehicle and control method thereof - Google Patents

Abstract

An unburned fuel adsorbed on a purification catalyst of a purification device after an internal combustion engine is started is quickly burned.
A fuel increase amount Tadd obtained by increasing the fuel with respect to the fuel injection by the stoichiometric air-fuel ratio is calculated from the fuel injection amount integrated value Fa until the intake air amount integrated value Ga reaches a threshold value Gref or more from the start of the engine. At the same time, the fuel amount Tadd is multiplied by the stoichiometric air-fuel ratio to calculate the air amount Gc necessary to completely burn the fuel of the fuel amount Tadd (S240, S250), and the engine is motored by cutting the fuel. The engine is motored with the fuel cut until the intake air amount integrated value Gb reaches the air amount Gc (S260 to S300). Thereby, the unburned fuel adsorbed by the purification catalyst of the purification device by the fuel increase from the start of the engine can be quickly burned and discharged to the atmosphere.
[Selection] Figure 3

Description

  The present invention relates to a hybrid vehicle and a control method therefor, and more specifically, an internal combustion engine to which a purification device having a purification catalyst for purifying exhaust gas is attached, a first electric motor capable of motoring the internal combustion engine, and driving power. When the internal combustion engine is started, the fuel injection amount is larger than the stoichiometric air-fuel ratio until the predetermined condition is satisfied when the internal combustion engine is started, the second motor capable of output, the power storage means capable of exchanging electric power with the first motor and the second motor BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid vehicle including a start time control unit that starts an internal combustion engine with an increase in fuel to be injected, and a method for controlling such a hybrid vehicle.

  Conventionally, as this type of hybrid vehicle, when the engine is temporarily stopped, a motor generator that applies a load to the engine after shutting off the fuel to the engine and brakes the idling of the engine after the fuel is shut off has been proposed. (For example, refer to Patent Document 1). In this vehicle, such control prevents the exhaust gas rich in oxygen from being discharged into the catalytic converter after the fuel is shut off.

Japanese Patent Laid-Open No. 2002-130001

  In general, when starting the engine, the fuel is increased so that the fuel injection amount is larger than the stoichiometric air-fuel ratio in order to improve the engine startability. In the cold start, the engine is started with a relatively large fuel increase in consideration of fuel adhering to the intake pipe and the cylinder wall. For this reason, unburned fuel is adsorbed by the catalyst of the purification device that purifies the exhaust, and in some cases, unburned fuel is discharged to the atmosphere. To deal with these problems, it is conceivable that the engine is operated with the air-fuel ratio larger than the stoichiometric air-fuel ratio after starting the engine. However, it takes time to completely burn the unburned fuel adsorbed on the catalyst. End up.

  The main object of the hybrid vehicle and the control method thereof of the present invention is to quickly burn the unburned fuel adsorbed on the purification catalyst of the purification device after starting the internal combustion engine.

  The hybrid vehicle of the present invention and its control method employ the following means in order to achieve the main object described above.

The hybrid vehicle of the present invention
An internal combustion engine having a purification device having a purification catalyst for purifying exhaust gas, a first electric motor capable of motoring the internal combustion engine, a second electric motor capable of outputting driving power, the first electric motor, and the Electric storage means capable of exchanging electric power with the second electric motor, and the internal combustion engine with an increase in fuel to inject more fuel than the stoichiometric air-fuel ratio until the predetermined condition is satisfied when the internal combustion engine is started A hybrid vehicle comprising a start time control means for starting the vehicle,
The starting-time control means calculates an incremental fuel injection amount that is incremental from the fuel injection amount by the theoretical air-fuel ratio among the fuel injection amounts injected until the predetermined condition is satisfied, and after the predetermined condition is satisfied, Means for controlling the first electric motor so that the internal combustion engine is motored in a state where the fuel injection is stopped until the integrated value of the intake air amount reaches the air amount necessary for complete combustion of the calculated incremental fuel injection amount. Is,
This is the gist.

  In the hybrid vehicle of the present invention, the incremental fuel injection amount that is incremental from the fuel injection amount by the stoichiometric air-fuel ratio is calculated from the fuel injection amounts that are injected until the predetermined condition is satisfied after the internal combustion engine is started. After the establishment, the first electric motor is operated so that the internal combustion engine is motored in a state where the fuel injection is stopped until the integrated value of the intake air amount reaches the air amount necessary for complete combustion of the calculated incremental fuel injection amount. Control. Thereby, after the internal combustion engine is started, the unburned fuel adsorbed on the purification catalyst of the purification device can be quickly burned. Of course, it can drive | work with a 1st electric motor.

  In such a hybrid vehicle of the present invention, the start time control means controls to perform motoring of the internal combustion engine after the predetermined condition is satisfied only when the temperature of the cooling medium of the internal combustion engine is equal to or lower than the predetermined temperature. It can also be a means. This is based on the fact that a large amount of fuel is increased when the temperature of the cooling medium of the internal combustion engine is low.

  In the hybrid vehicle of the present invention, the predetermined condition may be a condition in which an integrated value of the intake air amount after starting the internal combustion engine reaches a predetermined amount. This is based on the fact that it can be determined from the integrated value of the intake air amount as an index for determining whether or not the internal combustion engine has been in a stable operation state after the internal combustion engine is started.

The hybrid vehicle control method of the present invention includes:
An internal combustion engine having a purification device having a purification catalyst for purifying exhaust gas, a first electric motor capable of motoring the internal combustion engine, a second electric motor capable of outputting driving power, the first electric motor, and the Electric storage means capable of exchanging electric power with the second electric motor, and the internal combustion engine with an increase in fuel to inject more fuel than the stoichiometric air-fuel ratio until the predetermined condition is satisfied when the internal combustion engine is started A method for controlling a hybrid vehicle that starts a vehicle,
When starting the internal combustion engine, an incremental fuel injection amount that is incremental from the fuel injection amount by the stoichiometric air-fuel ratio among the fuel injection amounts injected until the predetermined condition is satisfied is calculated, and after the predetermined condition is satisfied, Controlling the first electric motor so that the internal combustion engine is motored in a state where the fuel injection is stopped until the integrated value of the intake air amount reaches the air amount necessary for complete combustion of the calculated incremental fuel injection amount;
It is characterized by that.

  In this hybrid vehicle control method of the present invention, an incremental fuel injection amount that is incremental from the fuel injection amount by the stoichiometric air-fuel ratio among the fuel injection amounts that are injected until the predetermined condition is satisfied after the internal combustion engine is started, After the predetermined condition is satisfied, the internal combustion engine is motored so that the fuel injection is stopped until the integrated value of the intake air amount reaches the air amount necessary for complete combustion of the calculated incremental fuel injection amount. 1 Control the motor. Thereby, after the internal combustion engine is started, the unburned fuel adsorbed on the purification catalyst of the purification device can be quickly burned. Of course, it can drive | work with a 1st electric motor.

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. 3 is a flowchart illustrating an example of a start time fuel injection process executed by an engine ECU 24; It is explanatory drawing which shows typically the relationship between the rotation speed Ne of the engine 22, and fuel injection quantity. It is a flowchart which shows a part of example of the fuel injection process at the time of start of a modification. 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. FIG. 11 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 320 of a modified example. FIG. 11 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 420 according to a modification.

  Next, the form for implementing this invention is demonstrated using an Example.

  FIG. 1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 equipped with a power output apparatus 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. Inhalation and gasoline are injected from the fuel injection valve 126 to mix the sucked air and gasoline. The mixture is sucked into the fuel chamber through the intake valve 128 and is 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 26. The exhaust from the engine 22 is discharged to the outside air through a purification device 134 having a purification catalyst (three-way catalyst) that purifies harmful components such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx). Is done.

  The engine 22 is controlled by an engine electronic control unit (hereinafter referred to as 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 26, 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 , The throttle position from the throttle valve position sensor 146 that detects the position of the throttle valve 124, the intake air amount Qa from the air flow meter 148 attached to the intake pipe, and the temperature sensor 149 also attached to the intake pipe Intake air temperature, 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 engine ECU 24 also calculates the rotational speed Ne of the engine 22 based on the crank position from the crank position sensor 140.

  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. 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 the communication port, and exchanges various control signals and data with the engine ECU 24, the motor ECU 40, and the battery ECU 52. ing.

  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 so as 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. The torque conversion operation mode and the charge / discharge operation mode are modes in which the engine 22 and the motors MG1, MG2 are controlled so that the required power is output to the ring gear shaft 32a with the operation of the engine 22. Since there is no difference in the control, both are hereinafter referred to as the engine operation mode.

  In the engine operation mode, the hybrid electronic control unit 70 requires the required torque Tr to be output to the ring gear shaft 32a as the drive shaft based on the accelerator opening Acc from the accelerator pedal position sensor 84 and the vehicle speed V from the vehicle speed sensor 88. * Is set, and the conversion factor is converted into the rotation speed obtained by dividing the rotation speed Nr of the ring gear shaft 32a (for example, the rotation speed Nm2 of the motor MG2 by the gear ratio of the reduction gear 35) to the set required torque Tr *. The traveling power Pr * required for traveling is calculated by multiplying the number of revolutions obtained by multiplication), and charging / discharging of the battery 50 obtained from the calculated traveling power Pr * based on the remaining capacity (SOC) of the battery 50 As the power to be output from the engine 22 by reducing the required power Pb * (positive value when discharging from the battery 50) An engine using an operation line (for example, a fuel efficiency optimum operation line) as a relationship between the rotational speed Ne of the engine 22 and the torque Te that can set the required power Pe * and output the required power Pe * from the engine 22 efficiently. The target rotational speed Ne * and the target torque Te * of 22 are set so that the rotational speed Ne of the engine 22 becomes the target rotational speed Ne * within the range of the input / output limits Win and Wout of the battery 50. A torque command Tm1 * as a torque to be output from the motor MG1 is set by the rotational speed feedback control, and a torque acting on the ring gear shaft 32a via the power distribution and integration mechanism 30 when the motor MG1 is driven by the torque command Tm1 *. The torque command Tm2 * of the motor MG2 is set by subtracting from the required torque Tr *, and the target rotational speed Ne * Send for the engine ECU24 target torque Te * city, the torque command Tm1 *, the Tm2 * is sent to the motor ECU 40. The engine ECU 24 that has received the target rotational speed Ne * and the target torque Te * sets a target EGR rate Re * as a target value for the EGR rate Re based on the target rotational speed Ne * and the target torque Te *. In addition, intake air amount control, fuel injection control, ignition control, and the like of the engine 22 are performed so that the engine 22 is operated by the target rotational speed Ne * and the target torque Te * so that the EGR rate Re becomes the target EGR rate Re *. The opening degree of the EGR valve 164 of the EGR system 160 is adjusted. The motor ECU 40 that has received the torque commands Tm1 * and Tm2 * performs switching control of the switching elements of the inverters 41 and 42 so that the motors MG1 and MG2 are driven by the torque commands Tm1 * and Tm2 *.

  In the motor operation mode, the hybrid electronic control unit 70 sets the torque command Tm1 * of the motor MG1 to a value of 0 and the required torque Tr * as a drive shaft within the range of the input / output limits Win and Wout of the battery 50. The torque command Tm2 * of the motor MG2 is set so as to be output to the shaft 32a and transmitted to the motor ECU 40. Then, the motor ECU 40 that receives the torque commands Tm1 * and Tm2 * performs switching control of the switching elements of the inverters 41 and 42 so that the motors MG1 and MG2 are driven by the torque commands Tm1 * and Tm2 *.

  Next, the operation of the hybrid vehicle 20 of the embodiment configured as described above, particularly the operation of fuel injection when starting the engine 22 will be described. When the ignition switch 80 is turned on when the engine 22 is cold, such as −10 ° C. or −20 ° C., the accelerator opening Acc, the vehicle speed V, and the remaining capacity (SOC) of the battery 50 When the vehicle required power P * calculated based on the above reaches a predetermined starting value Pstart or more, the vehicle is started when a heating request is made by a heating request from an air conditioner (not shown) of the vehicle. When the vehicle required power P * reaches less than a predetermined stop value Pstop in the absence of the vehicle, the operation is stopped. The engine 22 is started by motoring the engine 22 by outputting a motoring torque for motoring the engine 22 from the motor MG1 and receiving the reaction force by a torque output from the motor MG2 or a parking lock. The fuel injection from the fuel injection valve 126 and ignition by the spark plug 130 are started. FIG. 3 is a flowchart showing an example of a start time fuel injection process executed by the engine ECU 24 when the engine 22 is started. The motoring of the engine 22 is performed by setting the motoring torque as the torque command Tm1 * of the motor MG1 by the hybrid electronic control unit 70, and transmitting this to the motor ECU 40 by communication, and the torque command in which the motoring torque is set. The motor ECU 40 that receives Tm1 * performs switching control of the switching element of the inverter 41 so that the torque of the torque command Tm1 * is output from the motor MG1.

  When the fuel injection process at start-up is executed, the CPU 24a of the engine ECU 24 first detects the rotational speed Ne of the engine 22, the elapsed time t after motoring the engine 22, and the water temperature sensor when starting the engine 22 is started. Data necessary for the fuel injection processing, such as the cooling water temperature Tw detected by 142 and the intake air amount Qa detected by the air flow meter 148, are input (step S100), and the input temperature Tw is compared with the threshold value Twref (step S110). . Here, the threshold value Twref is a fuel injection in which the amount of fuel is greatly increased so that the air-fuel ratio is significantly smaller than the stoichiometric air-fuel ratio (the fuel ratio is greatly increased) in order to ensure good startability of the engine 22. It is determined whether or not the amount (pre-startup injection amount Tst) is injected from the fuel injection valve 126, and a relatively low temperature (for example, −15 ° C. or −20 ° C.) can be used.

  When the coolant temperature Tw when starting the engine 22 is less than the threshold value Twref, it is determined whether or not the rotational speed Ne of the engine 22 is less than the threshold value Nref1 (step S120), and the rotational speed Ne of the engine 22 is the threshold value. When it is less than Nref1, it is determined that it is necessary to inject the fuel injection amount (pre-startup injection amount Tst) that has been increased significantly from the fuel injection valve 126, and the pre-startup fuel injection amount Tst is set as the fuel injection amount T. (Step S130), the fuel injection valve 126 is opened for the fuel injection time corresponding to the set fuel injection amount T (Step S200). Here, the threshold value Nref1 is a fuel injection in which the amount of fuel is greatly increased so that the air-fuel ratio is significantly smaller than the stoichiometric air-fuel ratio (the fuel ratio is greatly increased) in order to ensure good startability of the engine 22. This is a threshold for determining whether or not to inject the amount (pre-startup injection amount Tst) from the fuel injection valve 126, and a relatively small rotational speed (for example, 400 rpm) is used as the rotational speed Ne of the engine 22. Can do. Then, the current fuel injection amount T is added to the previous fuel injection amount integrated value Fa to calculate a new fuel injection amount integrated value Fa (step S210), and the current intake air is added to the previous intake air amount integrated value Ga. A new intake air amount integrated value Ga is calculated by adding the amount Qa (step S220), and it is determined whether or not the calculated intake air amount integrated value Ga is equal to or greater than the threshold value Gref (step S230). When the value Ga has not reached the threshold value Gref or more, the process returns to step S100. Here, the threshold value Gref is an integrated value of the intake air amount Qa necessary until the engine 22 after the start can be stably operated, and can be determined by an experiment or the like. In the above control, when the coolant temperature Tw when starting the engine 22 is less than the threshold value Twref, the pre-starting fuel injection amount Tst is set as the fuel injection amount T until the rotational speed Ne of the engine 22 reaches the threshold value Nref1 or more. The fuel injection amount integrated value Fa and the intake air amount integrated value Ga are calculated.

  When the rotational speed Ne of the engine 22 reaches the threshold value Nref1 or more, it is determined in step S120 that the rotational speed Ne of the engine 22 is greater than or equal to the threshold value Nref1, and the engine 22 is started according to an elapsed time t after starting the motoring of the engine 22. A start-time injection amount T0, which is a fuel injection amount at the time, is set (step S140), and it is determined whether or not the rotational speed Ne of the engine 22 is less than a threshold value Nref2 (step S150). Here, the starting injection amount T0 is set as a fuel injection amount at which the air-fuel ratio is smaller than the stoichiometric air-fuel ratio (the fuel ratio is larger) in order to cause explosion combustion more reliably in the engine 22 immediately after starting. And is set so as to gradually decrease in accordance with the elapsed time t from the start of motoring of the engine 22. Therefore, the starting injection amount T0 is a fuel injection amount considerably smaller than the pre-starting injection amount Tst. Further, the threshold value Nref2 is a start-time injection amount T0 with a gradual change in the fuel injection amount from the pre-startup injection amount Tst in order to smoothly change the rotational speed Ne of the engine 22 when fuel injection of the pre-startup injection amount Tst is performed. Is set as the upper limit of the number of rotations to be shifted to, and the number of rotations is larger than the threshold value Nref1 (for example, 600 rpm). When it is determined that the rotational speed Ne of the engine 22 is less than the threshold value Nref2, it is determined that it is necessary to shift the fuel injection amount from the pre-starting injection amount Tst to the starting injection amount T0 with a gradual change, and the rotational speed Ne of the engine 22 is determined. Is used to set the correction amount Ta according to the following equation (1) (step S160), and the fuel injection amount T is set as the sum of the starting injection amount T0 and the correction amount Ta (step S170). The fuel injection valve 126 is opened for the fuel injection time corresponding to the amount T (step S200), the fuel injection amount integrated value Fa and the intake air amount integrated value Ga are calculated (steps S210 and S220), and the calculated intake air is calculated. It is determined whether or not the amount integrated value Ga has reached the threshold value Gref or more (step S230), and the intake air amount integrated value Ga has not reached the threshold value Gref or more. It returns to step S100. Therefore, the starting injection amount T0 corresponding to the elapsed time t from the start of motoring of the engine 22 until the rotational speed Ne of the engine 22 reaches the threshold value Nref2 or more and the correction amount Ta obtained by the equation (1). The sum is set as the fuel injection amount T and fuel is injected, and the integrated value Fa of the fuel injection amount injected during that time and the integrated value Ga of the intake air amount are calculated.

  Ta = (Tst-T0) ・ (Nref2-Ne) / (Nref2-Nref1) (1)

  When the rotational speed Ne of the engine 22 reaches the threshold value Nref2 or more, it is determined in step S150 that the rotational speed Ne of the engine 22 is greater than or equal to the threshold value Nref2, and the fuel injection amount is gradually changed from the pre-starting injection amount Tst to the starting injection amount T0. It is determined that the rotational speed range to be shifted to is exceeded, the starting injection amount T0 is set as the fuel injection amount T (step S190), and the fuel injection valve 126 is set for the fuel injection time corresponding to the set fuel injection amount T. Is opened (step S200), the fuel injection amount integrated value Fa and the intake air amount integrated value Ga are calculated (steps S210 and S220), and whether or not the calculated intake air amount integrated value Ga reaches or exceeds the threshold value Gref. (Step S230), and when the intake air amount integrated value Ga has not reached the threshold value Gref or more, the process returns to step S100.Therefore, when the rotational speed Ne of the engine 22 is equal to or greater than the threshold value Nref2, the starting injection amount T0 corresponding to the elapsed time t from the start of motoring of the engine 22 until the intake air amount integrated value Ga reaches the threshold value Gref or greater. Is set as the fuel injection amount T and fuel is injected, and the integrated value Fa of the fuel injection amount injected during that time and the integrated value Ga of the intake air amount are calculated.

  Consider a case where the coolant temperature Tw of the engine 22 when the motoring of the engine 22 by the motor MG1 is started to start the engine 22 is lower than the threshold value Twref. In this case, when it is determined that the rotational speed Ne of the engine 22 is less than the threshold value Nref1, while the rotational speed Ne of the engine 22 is less than the threshold value Nref1, the fuel injection amount Tst is a fuel injection amount Tst. The fuel is injected with the setting. As a result, the engine 22 starts well. When the rotational speed Ne of the engine 22 becomes equal to or higher than the threshold value Nref1 due to motoring of the motor MG1, the starting injection amount T0 based on the elapsed time t from the start of motoring and the above-described injection amount T0 until the rotational speed Ne reaches the threshold value Nref2. The fuel injection amount T is set as the sum of the correction amount Ta calculated by the equation (1), and the fuel is injected. For this reason, since the fuel injection amount does not change suddenly, the change in the rotational speed Ne of the engine 22 can be performed smoothly. When the rotational speed Ne of the engine 22 becomes equal to or greater than the threshold value Nref2, the starting injection amount T0 based on the elapsed time t from the start of motoring is set to the fuel injection amount T and fuel is injected. FIG. 4 schematically shows the relationship between the rotational speed Ne of the engine 22 and the fuel injection amount.

  If the coolant temperature Tw when starting the engine 22 is equal to or higher than the threshold value Twref, it is determined in step S110 that the coolant temperature Tw is equal to or higher than the threshold value Twref, and it is necessary to reduce the pre-startup injection amount Tst by fuel injection or its gradual change. It is determined that there is no fuel injection, and a starting injection amount T0, which is a fuel injection amount at the time of starting, is set according to an elapsed time t after the start of motoring of the engine 22 (step S180). The fuel injection amount T is set (step S190), the fuel injection valve 126 is opened for the fuel injection time corresponding to the set fuel injection amount T (step S200), and the fuel injection amount integrated value Fa and the intake air amount integrated value are set. Ga is calculated (steps S210 and S220), and it is determined whether or not the calculated intake air amount integrated value Ga reaches or exceeds the threshold value Gref. Step S230), it returns to step S100 when the intake air amount integrated value Ga has not reached the threshold value or more Gref. Accordingly, when the cooling water temperature Tw of the engine 22 when starting the motoring of the engine 22 by the motor MG1 to start the engine 22 is equal to or higher than the threshold value Twref, the pre-starting injection amount Tst is decreased by fuel injection or its gradual change. Without starting the operation, the starting injection amount T0 based on the elapsed time t from the start of motoring is set as the fuel injection amount T and fuel is injected until the intake air amount integrated value Ga reaches the threshold value Gref or more. . As a result, inconveniences caused by the start of the engine 22 due to excessive fuel injection, such as misfires of the engine 22 and torque pulsations, can be suppressed.

  If it is determined in step S230 that the intake air amount integrated value Ga has reached or exceeded the threshold value Gref, the fuel injection amount integrated value Fa divided by the stoichiometric air fuel ratio is subtracted from the fuel injection amount integrated value Fa. The amount of fuel increase Tadd obtained by increasing the fuel with respect to the fuel injection is calculated (step S240), and the amount of air necessary for completely burning the fuel of the fuel increase amount Tadd by multiplying the calculated fuel increase amount Tadd by the theoretical air-fuel ratio. Gc is calculated (step S250). Then, in a state where the fuel of the engine 22 is cut, a control signal to be motored by the motor MG1 at the rotation speed Ne of the engine 22 at that time is transmitted to the hybrid electronic control unit 70 and fuel injection to the engine 22 is stopped and fuel is supplied. Cutting is started (step S260), and the process of calculating the intake air amount integrated value Gb by inputting the intake air amount Qa until the intake air amount integrated value Gb during the fuel cut reaches the air amount Gc or more is repeated (step S270). To Step S290), when the intake air amount integrated value Gb during the fuel cut reaches the air amount Gc or more, a control signal for terminating the fuel cut is transmitted to the hybrid electronic control unit 70 and the fuel cut is terminated. (Step S300), the start-up fuel injection process is terminated.

  According to the hybrid vehicle 20 of the embodiment described above, the engine 22 is motored in a state where the fuel is cut when the intake air amount integrated value Ga reaches the threshold value Gref from the start of the start of the engine 22. The unburned fuel adsorbed on the purification catalyst of the purification device 134 can be quickly burned and discharged to the atmosphere by increasing the amount of fuel from the start of starting. In addition, the fuel increase amount Tadd obtained by increasing the fuel with respect to the fuel injection by the stoichiometric air-fuel ratio among the fuel injection amount integrated value Fa from the start of the engine 22 until the intake air amount integrated value Ga reaches the threshold value Gref or more is calculated. Multiplying the fuel increase amount Tadd by the stoichiometric air-fuel ratio to calculate the air amount Gc necessary to completely burn the fuel of the fuel increase amount Tadd, and integrating the intake air amount when the engine 22 is motored with the fuel cut Since the fuel cut is terminated when the value Gb reaches the air amount Gc, excessive air is not supplied to the purification catalyst. Thereby, the fuel injection amount to the engine 22 can be quickly stoichiometric.

  In the hybrid vehicle 20 of the embodiment, regardless of the coolant temperature Tw when the engine 22 is started, the fuel injection amount integrated value from when the engine 22 starts to when the intake air amount integrated value Ga reaches the threshold value Gref or more. The amount of air necessary to completely burn the fuel of the fuel increase amount Tadd by calculating the fuel increase amount Tadd that is increased in fuel relative to the fuel injection by the stoichiometric air-fuel ratio and multiplying the fuel increase amount Tadd by the stoichiometric air-fuel ratio. The engine 22 is motored in a state where the fuel is cut until the intake air amount integrated value Gb reaches the air amount Gc when the fuel is cut and the engine 22 is motored. The fuel increase amount Tadd and the air amount Gc are calculated only when the coolant temperature Tw when starting the engine is less than the threshold value Twref, The engine 22 may alternatively be motoring in a state where the intake air amount integrated value Gb is fuel cut up to the amount of air Gc when cut fees are motoring the engine 22. FIG. 5 shows a part of a flowchart of an example of the starting fuel injection process in this case.

  In the hybrid vehicle 20 of the embodiment, the motor MG2 is attached to the ring gear shaft 32a as the drive shaft via the reduction gear 35. However, the motor MG2 may be directly attached to the ring gear shaft 32a, or Instead, the motor MG2 may be attached to the ring gear shaft 32a via a transmission such as a 2-speed, 3-speed, or 4-speed.

  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. 6) 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.

  In the hybrid vehicle 20 of the embodiment, the power from 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, and the power from the motor MG2 is reduced to the reduction gear. However, the motor MG is connected to the drive shaft connected to the drive wheels 63a and 63b via the transmission 330, as exemplified in the hybrid vehicle 320 of the modified example of FIG. The engine 22 is connected to the rotation shaft of the motor MG via the clutch 329, and the power from the engine 22 is output to the drive shaft via the rotation shaft of the motor MG and the transmission 330, and from the motor MG. This power may be output to the drive shaft via the transmission 330. Alternatively, as illustrated in the hybrid vehicle 420 of the modified example of FIG. 9, the power from the engine 22 is output to the axle connected to the drive wheels 63a and 63b via the transmission 430 and the power from the motor MG is driven. It may be output to an axle different from the axle to which the wheels 63a, 63b are connected (the axle connected to the wheels 64a, 64b in FIG. 9). That is, any type of hybrid vehicle may be used as long as it includes an engine that outputs power for traveling and an electric motor that outputs power for traveling.

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

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the engine 22 to which the purification device 134 is attached corresponds to the “internal combustion engine”, the motor MG1 corresponds to the “first electric motor”, the motor MG2 corresponds to the “second electric motor”, and the battery 50 is “ When the cooling water temperature Tw of the engine 22 when motoring is started is less than the threshold value Twref, the fuel ratio is significantly large until the engine speed Ne reaches the threshold value Nref or more. Fuel injection is performed with the injection amount Tst set as the fuel injection amount T, and when the engine speed Ne reaches the threshold value Nref1 or more, the engine starts based on the elapsed time t from the start of motoring until the engine speed Ne reaches the threshold value Nref2. The sum of the hourly injection amount T0 and the correction amount Ta is set as the fuel injection amount T, and fuel is injected, so that the rotational speed Ne of the engine 22 reaches the threshold value Nref2 or more. And the engine when the motoring is started by setting the starting injection amount T0 based on the elapsed time t from the start of the motoring as the fuel injection amount T until the intake air amount integrated value Ga reaches the threshold value Gref or more. When the coolant temperature Tw of 22 is equal to or higher than the threshold value Twref, the starting injection amount T0 based on the elapsed time t from the start of motoring is set as the fuel injection amount T until the intake air amount integrated value Ga reaches the threshold value Gref or higher. Of the fuel injection amount integrated value Fa from the start of starting the engine 22 until the intake air amount integrated value Ga becomes equal to or greater than the threshold value Gref, a fuel increase amount Tadd obtained by increasing the fuel with respect to the fuel injection by the theoretical air-fuel ratio is calculated. At the same time, multiply the fuel increase amount Tadd by the stoichiometric air-fuel ratio to calculate the amount of air Gc required to completely burn the fuel of the fuel increase amount Tadd. The engine that performs the fuel injection process at the time of start in FIG. 3 that motors the engine 22 in a state where the fuel is cut until the intake air amount integrated value Gb reaches the air amount Gc when the fuel is cut and the engine 22 is motored. The ECU 24, the hybrid electronic control unit 70, and the motor ECU 40 correspond to “starting time control means”.

  Here, the “internal combustion engine” is not limited to an internal combustion engine that outputs power using a hydrocarbon fuel such as gasoline or light oil, and may be any type of internal combustion engine such as a hydrogen engine. The “first motor” is not limited to the motor MG1 configured as a synchronous generator motor, and may be any type of generator such as an induction motor that can input and output power. The “second electric motor” is not limited to the motor MG2 configured as a synchronous generator motor, and may be any type of electric motor such as an induction motor that can input and output power to the drive shaft. I do not care. The “power storage means” is not limited to the battery 50 as a secondary battery, and may be anything as long as it can exchange power with a power power input / output means such as a capacitor and an electric motor. The “starting time control means” is not limited to the combination of the engine ECU 24, the hybrid electronic control unit 70, and the motor ECU 40, and may be configured by a single electronic control unit. Further, as the “starting time control means”, when the cooling water temperature Tw of the engine 22 when starting the motoring is less than the threshold value Twref, the fuel ratio is greatly increased until the rotational speed Ne of the engine 22 reaches the threshold value Nref or more. The fuel injection amount T is set as a large pre-startup injection amount Tst. When the engine speed Ne reaches the threshold value Nref1 or more, the elapsed time from the start of motoring until the engine speed Ne reaches the threshold value Nref2. The sum of the starting injection amount T0 based on t and the correction amount Ta is set as the fuel injection amount T to inject fuel, and when the rotational speed Ne of the engine 22 reaches the threshold value Nref2 or more, the intake air amount integrated value Ga becomes the threshold value Gref. Until this time, the starting injection amount T0 based on the elapsed time t from the start of motoring is set as the fuel injection amount T and fuel is injected. When the cooling water temperature Tw of the engine 22 when starting the engine is equal to or higher than the threshold value Twref, the fuel injection is performed at the starting injection amount T0 based on the elapsed time t from the start of motoring until the intake air amount integrated value Ga reaches the threshold value Gref or higher. Fuel injection is performed with the amount set as T, and the fuel is increased with respect to the fuel injection by the stoichiometric air-fuel ratio in the fuel injection amount integrated value Fa from the start of the engine 22 until the intake air amount integrated value Ga reaches the threshold value Gref or more. The fuel increase amount Tadd is calculated, and the fuel increase amount Tadd is multiplied by the stoichiometric air-fuel ratio to calculate the air amount Gc required to completely burn the fuel of the fuel increase amount Tadd, and the fuel is cut and the engine 22 is motored. When the engine 22 is motored with the fuel cut until the integrated intake air amount Gb reaches the air amount Gc. The starting injection amount based on the elapsed time t from the start of motoring until the intake air amount integrated value Ga reaches the threshold value Gref or higher, regardless of the cooling water temperature Tw of the engine 22 when the motoring is started. The fuel increase amount Tadd and the air amount Gc are calculated only when the fuel injection amount T0 is set as the fuel injection amount T or when the cooling water temperature Tw when the engine 22 is started is less than the threshold value Twref. The internal combustion engine is started by, for example, motoring the engine 22 in a state where the fuel is cut until the intake air amount integrated value Gb reaches the air amount Gc when the fuel is cut and the engine 22 is motored. Sometimes the internal combustion engine is started with a fuel increase amount that injects more fuel than the stoichiometric air-fuel ratio until a predetermined condition after starting is satisfied, Of the fuel injection amounts injected until the predetermined condition is satisfied, the incremental fuel injection amount that is incremental from the fuel injection amount by the theoretical air-fuel ratio is calculated, and the incremental fuel injection amount that is calculated after the predetermined condition is satisfied is completely burned Any method may be used as long as it controls the first electric motor so that the internal combustion engine is motored in a state where the fuel injection is stopped until the integrated value of the intake air amount reaches the required air amount.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the same as that of the embodiment described in the column of means for solving the problem. Therefore, the elements of the invention described in the column of means for solving the problems are not limited. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problems. It is only a specific example.

  As mentioned above, although the form for implementing this invention was demonstrated using the Example, this invention is not limited at all to such an Example, In the range which does not deviate from the summary of this invention, it is with various forms. Of course, it can be implemented.

  The present invention can be used in the manufacturing industry of hybrid vehicles.

  20, 120, 220, 320, 420 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 electronic control unit for motor (motor ECU), 41, 42 inverter, 43, 44 rotational position detection sensor, 50 battery, 51 temperature sensor, 52 Electronic control unit for battery (battery ECU), 54 power line, 60 gear mechanism, 62 differential gear, 63a, 63b drive wheel, 64a, 64b wheel, 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, 122 air cleaner, 124 throttle Valve, 126 Fuel injection valve, 128 Intake valve, 130 Spark plug, 132 Piston, 134 Purification device, 135a Air-fuel ratio sensor, 135b Oxygen sensor, 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 Capacitors, 150 variable valve timing mechanism, 230 pair-rotor motor, 232 an inner rotor, 234 outer rotor, 329 clutches, 330 and 430 transmission, MG, MG1, MG2 motor.

Claims (4)

An internal combustion engine having a purification device having a purification catalyst for purifying exhaust gas, a first electric motor capable of motoring the internal combustion engine, a second electric motor capable of outputting driving power, the first electric motor, and the Electric storage means capable of exchanging electric power with the second electric motor, and the internal combustion engine with an increase in fuel to inject more fuel than the stoichiometric air-fuel ratio until the predetermined condition is satisfied when the internal combustion engine is started A hybrid vehicle comprising a start time control means for starting the vehicle,
The starting-time control means calculates an incremental fuel injection amount that is incremental from the fuel injection amount by the theoretical air-fuel ratio among the fuel injection amounts injected until the predetermined condition is satisfied, and after the predetermined condition is satisfied, Means for controlling the first electric motor so that the internal combustion engine is motored in a state where the fuel injection is stopped until the integrated value of the intake air amount reaches the air amount necessary for complete combustion of the calculated incremental fuel injection amount. Is,
Hybrid car. The hybrid vehicle according to claim 1,
The start-up control means is means for controlling the internal combustion engine to perform motoring after the predetermined condition is satisfied only when the temperature of the cooling medium of the internal combustion engine is equal to or lower than a predetermined temperature.
Hybrid car. A hybrid vehicle according to claim 1 or 2,
The predetermined condition is a condition in which an integrated value of the intake air amount after starting the internal combustion engine reaches a predetermined amount.
Hybrid car. An internal combustion engine having a purification device having a purification catalyst for purifying exhaust gas, a first electric motor capable of motoring the internal combustion engine, a second electric motor capable of outputting driving power, the first electric motor, and the Electric storage means capable of exchanging electric power with the second electric motor, and the internal combustion engine with an increase in fuel to inject more fuel than the stoichiometric air-fuel ratio until the predetermined condition is satisfied when the internal combustion engine is started A method for controlling a hybrid vehicle that starts a vehicle,
When starting the internal combustion engine, an incremental fuel injection amount that is incremental from the fuel injection amount by the stoichiometric air-fuel ratio among the fuel injection amounts injected until the predetermined condition is satisfied is calculated, and after the predetermined condition is satisfied, Controlling the first electric motor so that the internal combustion engine is motored in a state where the fuel injection is stopped until the integrated value of the intake air amount reaches the air amount necessary for complete combustion of the calculated incremental fuel injection amount;
A control method for a hybrid vehicle.

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