JP2008247128A - POWER OUTPUT DEVICE, ITS CONTROL METHOD, AND VEHICLE - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible to start an internal combustion engine into operation, even if it is attempted to start the internal combustion engine, by cranking within the range of output restriction of a secondary battery in cold and failed to start. <P>SOLUTION: If it is attempted to start the engine into operation in colds but cannot start, the engine is started by clanking by outputting from the motor MG1, the torque restricted by the torque restriction Tm1max set as the torque larger than the torque required to rotate the engine at least starting minimum rotation speed Nref in the colds based on output limitation Wout of a battery at that time, irrespective of the battery voltage Vb turning into under the lower limit voltage Vmin (S240-S320). As a result, the engine can be started into operation, even if starting of the engine fails in cold periods. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power output apparatus, a control method therefor, and a vehicle.

Conventionally, in this type of power output device, when the engine is cranked by the generator motor and the engine is started and the engine fails to start, the engine speed during cranking by the generator motor is increased. There has been proposed an attempt to restart the engine (see, for example, Patent Document 1). In addition, when the internal combustion engine is in a low temperature environment where the apparatus temperature is low during start control, the internal combustion engine is temporarily supplied with a current exceeding the maximum rating to the motor for cranking the internal combustion engine and the inverter for driving the motor. There has also been proposed a method in which the motor is forcibly rotated and started (see, for example, Patent Document 2).
JP 2000-220557 A JP 2005-143270 A

  When the temperature of the outside air is low and the temperature of the secondary battery is low, the performance of the secondary battery decreases, and the output limit that is the maximum power that can be discharged to suppress the deterioration of the secondary battery is reduced. On the other hand, when the engine is cold, the internal combustion engine has a high viscosity of the lubricating oil, so the friction torque of the internal combustion engine increases, and the torque required to crank the internal combustion engine increases. Due to these factors, when starting the internal combustion engine by cranking the internal combustion engine within the range of the output limit of the secondary battery, the start of the internal combustion engine may fail. At this time, as described in the background art above, even if an attempt is made to restart the engine by increasing the number of revolutions during cranking of the internal combustion engine, the internal combustion engine is operated at a large number of revolutions to limit the output of the secondary battery. Can't crank. Moreover, even if an electric current exceeding the maximum rating is temporarily supplied to the electric motor or inverter, there may be a case where the current exceeding the maximum rating cannot be supplied due to the output limitation of the secondary battery. In a hybrid vehicle equipped with such a power output device, the secondary battery cannot be charged unless the internal combustion engine is started. Therefore, it is strongly desired to start the internal combustion engine.

  The power output apparatus, the control method thereof, and the vehicle according to the present invention attempt to start the internal combustion engine by cranking the engine within the range of the output limit of the secondary battery when cold, but start the internal combustion engine even when the start fails. The purpose is to do.

  The power output apparatus, the control method thereof, and the vehicle of the present invention employ the following means in order to achieve the above-described object.

The power output apparatus of the present invention is
A power output device that outputs power to a drive shaft,
An internal combustion engine used to output power to the drive shaft;
An electric motor used for cranking the internal combustion engine;
A secondary battery for supplying electric power to the electric motor;
An output limit setting means for setting an output limit that is an allowable maximum discharge power that can be discharged from the secondary battery based on a state of the secondary battery including a temperature of the secondary battery and an output voltage of the secondary battery; ,
The internal combustion engine is configured to crank the internal combustion engine and start the internal combustion engine by driving the electric motor within the set output limit range when an instruction to start the internal combustion engine is issued in the cold state. A normal start control for controlling the electric motor is executed, and when the internal combustion engine cannot be started even if the normal start control is executed, the electric motor is driven regardless of the set output limit. Start control means for controlling the internal combustion engine and the electric motor to crank the internal combustion engine to start the internal combustion engine,
It is a summary to provide.

  In this power output device of the present invention, when an instruction to start the internal combustion engine is issued in the cold state, first, the internal combustion engine is cranked by driving the electric motor within the range of the output limit of the secondary battery. The internal combustion engine and the electric motor are controlled to start. If the internal combustion engine cannot be started even after performing the normal start control, the internal combustion engine is cranked by driving the electric motor regardless of the output limit of the secondary battery. The internal combustion engine and the electric motor are controlled to start. At this time, the secondary battery discharges electric power exceeding the output limit. As a result, although the secondary battery is somewhat deteriorated, the internal combustion engine can be started. That is, even when the normal-time start control is executed, the internal combustion engine can be started more reliably even when the internal combustion engine cannot be started.

  In such a power output apparatus of the present invention, when the output voltage of the secondary battery is less than a predetermined lower limit voltage, the output limit setting means tends to decrease as the difference between the output voltage and the predetermined lower limit voltage increases. It may be a means for setting the output restriction. The start time control means is set by the output restriction setting means when starting the cranking again when the internal combustion engine cannot be started even if the normal time start control is executed. The internal combustion engine and the internal combustion engine are configured to crank the internal combustion engine and start the internal combustion engine by continuously outputting from the electric motor a torque necessary to start the internal combustion engine set based on an output limit. It may be a means for controlling the electric motor. In this way, it is possible to suppress deterioration of the secondary battery more than necessary.

  Further, in the power output apparatus of the present invention, the power is connected to three axes of the drive shaft, the output shaft of the internal combustion engine, and the rotating shaft of the electric motor, and input / output to / from any two of the three shafts. And a second electric motor capable of inputting / outputting power to / from the drive shaft.

  The vehicle of the present invention is the power output device of the present invention according to any one of the above-described aspects, that is, basically a power output device that outputs power to the drive shaft, and outputs power to the drive shaft. An internal combustion engine used; an electric motor used for cranking the internal combustion engine; a secondary battery that supplies electric power to the electric motor; and a temperature of the secondary battery and an output voltage of the secondary battery. Output limit setting means for setting an output limit that is the maximum allowable discharge power that can be discharged from the secondary battery based on the state of the engine, and when the start instruction for the internal combustion engine is issued in the cold state, the set output limit Driving the electric motor within a range of the engine to execute the normal start control for controlling the internal combustion engine and the electric motor so as to crank the internal combustion engine and start the internal combustion engine. Even if you run When the internal combustion engine cannot be started, the internal combustion engine and the electric motor are driven so as to crank the internal combustion engine and start the internal combustion engine by driving the electric motor regardless of the set output limit. And a start control means for controlling the power output device, and the axle is connected to the drive shaft.

  Since the vehicle according to the present invention is equipped with the power output device of the present invention according to any one of the above-described aspects, the internal combustion engine can be started even if the effects of the power output device of the present invention, for example, the normal start control is executed. Even when the operation cannot be performed, the same effects as the effect of starting the internal combustion engine more reliably can be obtained.

The method for controlling the power output apparatus of the present invention includes:
An internal combustion engine used to output power to the drive shaft; an electric motor used for cranking the internal combustion engine; a secondary battery for supplying electric power to the electric motor; a temperature of the secondary battery; and an output of the secondary battery Output limit setting means for setting an output limit that is an allowable maximum discharge power that can be discharged from the secondary battery based on a state of the secondary battery including a voltage, and a control method for a power output device comprising:
When an instruction to start the internal combustion engine is issued in the cold state, the internal combustion engine is cranked by driving the electric motor within the range of the output limit set by the output limit setting means, and the internal combustion engine is started. When the normal time start control for controlling the internal combustion engine and the electric motor is executed, and the normal time start control is not executed, the internal combustion engine cannot be started. Controlling the internal combustion engine and the electric motor to start the internal combustion engine by cranking the internal combustion engine by driving the electric motor regardless of output restriction;
It is characterized by that.

  In this method of controlling a power output apparatus according to the present invention, when an internal combustion engine start instruction is issued in the cold state, the internal combustion engine is first cranked by driving the electric motor within the range of the output limit of the secondary battery. The internal combustion engine and the electric motor are controlled to start the internal combustion engine. If the internal combustion engine cannot be started even after performing the normal start control, the internal combustion engine is cranked by driving the electric motor regardless of the output limit of the secondary battery. The internal combustion engine and the electric motor are controlled to start. At this time, the secondary battery discharges electric power exceeding the output limit. As a result, although the secondary battery is somewhat deteriorated, the internal combustion engine can be started. That is, even when the normal-time start control is executed, the internal combustion engine can be started more reliably even when the internal combustion engine cannot be started.

  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 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. 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 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 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 engine ECU 24 also calculates the rotational speed of the crankshaft 26, that is, 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 disposed 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 motor ECU 40 also calculates the rotational speeds Nm1 and Nm2 of the motors MG1 and MG2 based on signals from the rotational position detection sensors 43 and 44.

  The battery 50 is configured as a lithium ion secondary battery, for example, and is managed by a battery electronic control unit (hereinafter referred to as a battery ECU) 52. The battery ECU 52 is attached to a signal necessary for managing the battery 50, for example, the battery voltage Vb from the voltage sensor 51a installed between the terminals of the battery 50, the power line 54 connected to the output terminal of the battery 50. The charging / discharging current Ib from the received current sensor 51b, the battery temperature Tb from the temperature sensor 51c attached to the battery 50, and the like are input, and data on the state of the battery 50 is electronically controlled by communication as necessary. Output to unit 70. Further, the battery ECU 52 calculates the remaining capacity (SOC) based on the integrated value of the charge / discharge current Ib detected by the current sensor 51b in order to manage the battery 50, or calculates the remaining capacity (SOC) and battery temperature. Based on Tb, input / output limits Win and Wout, which are the maximum allowable power that may charge / discharge the battery 50, are calculated. The input / output limits Win and Wout of the battery 50 are set to basic values of the input / output limits Win and Wout based on the battery temperature Tb, and are input to the output limiting correction coefficient based on the remaining capacity (SOC) of the battery 50. It can be set by setting a correction coefficient for restriction and multiplying the basic value of the set input / output restrictions Win and Wout by the correction coefficient. FIG. 3 shows an example of the relationship between the battery temperature Tb and the input / output limits Win, Wout, and FIG. 4 shows an example of the relationship between the remaining capacity (SOC) of the battery 50 and the correction coefficients of the input / output limits Win, Wout.

  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. From the accelerator pedal position Acc, 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 outside air temperature sensor 89 attached in the vicinity of the front grille of the vehicle. The outside air temperature Tout is input through 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 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, when the hybrid vehicle 20 of the embodiment thus configured is operated, particularly when the outside air temperature Tout is cold at a predetermined temperature (for example, −15 ° C., −20 ° C., etc.) or less, the system is started and the engine 22 is started. Will be described. FIG. 5 is a flowchart showing an example of a cold start control routine executed by the hybrid electronic control unit 70 when the engine 22 is started for the first time after the cold start of the system.

  When the cold start control routine is executed, the CPU 72 of the hybrid electronic control unit 70 first controls the rotational speed Ne of the engine 22, the rotational speed Nm1, the battery voltage Vb, the output limit Wout of the battery 50, and the like. A process of inputting necessary data is executed (step S100). Here, the rotational speed Ne of the engine 22 is calculated based on a signal from the crank position sensor 140 and is input from the engine ECU 24 by communication. Further, the rotation speed Nm1 of the motor MG1 is calculated from the rotation position of the rotor of the motor MG1 detected by the rotation position detection sensor 43 and is input from the motor ECU 40 by communication. Further, the battery voltage Vb detected by the voltage sensor 51a is input from the battery ECU 52 by communication. Further, the input / output limits Win and Wout of the battery 50 are set based on the battery temperature Tb of the battery 50 and the remaining capacity (SOC) of the battery 50 and are input from the battery ECU 52 by communication.

  When the data is input in this way, the input battery voltage Vb is compared with a lower limit voltage Vmin preset in the battery 50 (step S110). Here, the lower limit voltage Vmin is a lower limit of a voltage range in which the battery 50 can perform its function as rated, and is set as an upper limit of a voltage range in which the battery 50 is likely to deteriorate when the voltage is lower than this voltage. . When the battery voltage Vb is less than the lower limit voltage Vmin, in order to suppress the deterioration of the battery 50, voltage correction of the output limit Wout is performed using the following equation (1) so that the battery voltage Vb approaches the lower limit voltage Vmin (step) S120). Expression (1) is a relational expression in feedback control. In Expression (1), kb1 is a gain of a proportional term, and kb2 is a gain of an integral term. When battery voltage Vb is equal to or higher than lower limit voltage Vmin, voltage correction of output limit Wout is not performed.

  Wout ← Wout-kb1 (Vmin-Vb) + kb2∫ (Vmin-Vb) dt (1)

  Subsequently, the temporary torque Tm1tmp is set as the torque to be output from the motor MG1 based on the torque map at the start of the engine 22 and the elapsed time t from the start of the start of the engine 22. (Step S130). FIG. 6 shows an example of a torque map when setting the torque to be output from the motor MG1 when the engine 22 is started, and an example of how the rotation speed Ne of the engine 22 changes. In the torque map of the embodiment, a relatively large torque is set using rate processing immediately after the time T1 when the engine 22 is instructed to start, and the rotational speed Ne of the engine 22 is rapidly increased. Torque that allows the engine 22 to be stably motored at the rotational speed N1 or more at a time T2 after the rotational speed Ne of the engine 22 has passed the resonance rotational speed band or after the time necessary for passing through the resonant rotational speed band. To reduce power consumption and reaction force in the ring gear shaft 32a as a drive shaft. Then, the torque is set to a value of 0 using rate processing from time T3 when the rotational speed Ne of the engine 22 reaches the rotational speed N1, and the torque for power generation is set from time T5 when the complete explosion of the engine 22 is determined. Here, the rotational speed N1 is a rotational speed at which fuel injection control or ignition control of the engine 22 is started when the engine 22 is started at a normal temperature. For example, 800 rpm or 1000 rpm can be used. Considering the cold state, the viscosity of the lubricating oil of the engine 22 is high during the cold state, so that the friction torque during cranking (motoring) of the engine 22 increases, and the output of the battery 50 during the cold state. Since the limit Wout is limited, it is desired to start the engine 22 quickly even if vibration due to resonance occurs. Therefore, the engine 22 can be started as the rotation speed at which the fuel injection control and ignition control of the engine 22 are started. The lowest starting speed Nref, which is the lowest speed, is used. For example, 200 rpm or 300 rpm can be used as the minimum starting rotational speed Nref. Accordingly, when the electric power discharged from the battery 50 is sufficient even when cold, the fuel injection control and the ignition control are started when the rotational speed Ne of the engine 22 reaches the minimum starting rotational speed Nref due to cranking by the motor MG1. Thus, the engine 22 can be started more quickly than at the normal temperature.

  When the temporary torque Tm1tmp of the motor MG1 is thus set, the torque limit Tm1max is calculated as an upper limit of the torque that may be output from the motor MG1 by dividing the output limit Wout of the battery 50 by the rotation speed Nm1 of the motor MG1 (step S140 ) The smaller one of the set temporary torque Tm1tmp and the calculated torque limit Tm1max is set as the torque command Tm1 * of the motor MG1 (step S150), and the set torque command Tm1 * is transmitted to the motor ECU 40 (step S160). Thus, although the temporary torque Tm1tmp is set by the torque map shown in FIG. 6, the temporary torque Tm1tmp is limited by the torque limit Tm1max calculated from the output limit Wout of the battery 50, and the torque command Tm1 * is set. The torque command Tm1 * becomes a small value when the voltage correction is performed by the drop of the battery voltage Vb. The motor ECU 40 that has received the torque command Tm1 * performs switching control of the switching element of the inverter 41 so that the motor MG1 is driven by the torque command Tm1 *. At this time, torque is output from the power distribution and integration mechanism 30 to the ring gear shaft 32a by the torque output of the motor MG1, but when the shift lever 81 is in the parking position, the torque is transmitted to the drive wheels 63a and 63b by the parking lock. When the shift lever 81 is in the neutral position, torque calculated as -Tm1 * / ρ using the gear ratio ρ (number of teeth of the sun gear / number of teeth of the ring gear) of the power distribution and integration mechanism 30 acts on the ring gear shaft 32a. However, torque is not transmitted to the drive wheels 63a and 63b by electromagnetically locking the motor MG2 so that the ring gear shaft 32a does not rotate. In the embodiment, the control of the motor MG2 when the shift lever 81 is in the neutral position does not form the core of the present invention, and thus the description thereof is omitted.

  The processes in steps S100 to S160 are repeated until either a preset scheduled start time elapses or the engine speed Ne is equal to or higher than the minimum engine start speed Nref. By such repeated processing, the battery voltage Vb of the battery 50 may drop due to the torque output from the motor MG1, and may fall below the lower limit voltage Vmin. At this time, as described above, the output limit Wout of the battery 50 set by the battery temperature Tb and the remaining capacity (SOC) is subjected to voltage correction, and the motor MG1 is within the range of the output limit Wout subjected to voltage correction. The engine 22 is cranked. Here, in order to prevent the engine 22 from being cranked or motored by the motor MG1 for a long period of time, the engine 22 can be started when the engine 22 is normally started. The time is set to be slightly longer than the time that can be started, and for example, 3 seconds or 4 seconds can be used.

  When the engine speed Ne reaches the minimum engine start speed Nref before the scheduled start time elapses after the engine 22 starts, a control signal for starting fuel injection control and ignition control is transmitted to the engine ECU 24. Then, fuel injection and ignition are started (step S190), and it is confirmed that a complete explosion occurs before the scheduled start time elapses (steps S200 and S210), and the cold start control routine ends.

  Since sufficient torque cannot be output from the motor MG1 due to voltage correction of the output limit Wout of the battery 50, the rotation speed Ne of the engine 22 is not increased until the scheduled start time elapses after the start of the engine 22. There may be cases where the engine speed does not reach the minimum starting speed Nref. FIG. 7 shows an example of the temporal change of the output torque Tm1 of the motor MG1 and the rotational speed Ne of the engine 22 in this case. In this case, the driving of the motor MG1 is temporarily stopped (step S220), and after waiting for a predetermined time (for example, 2 seconds or 3 seconds) to elapse (step S230), the engine 22 is started again. An attempt to restart the engine 22 is first performed by inputting the output limit Wout of the battery 50 (step S240) and rotating the engine 22 at the starting minimum speed Nref or more even when it is cold based on the output limit Wout. A torque larger than a certain torque is set as the torque limit Tm1max (step S250). At this time, the torque limit Tm1max is set to a larger value as the output limit Wout is larger. In the embodiment, the relationship between the output limit Wout and the torque limit Tm1max is set in advance and stored in the ROM 74 as a torque limit setting map. When the output limit Wout is given, the corresponding torque is derived from the map and the torque limit is set. Tm1max was set. An example of the torque limit setting map is shown in FIG.

  Subsequently, the temporary torque Tm1tmp is set as the torque to be output from the motor MG1 based on the elapsed time t after the restart of the engine 22 is started using the torque map of FIG. 6 (step S260). The smaller one of the temporary torque Tm1tmp and the set torque limit Tm1max is set as the torque command Tm1 * of the motor MG1 (step S270), and the set torque command Tm1 * is transmitted to the motor ECU 40 (step S280). Then, the rotational speed Ne of the engine 22 is input (step S290), it is determined whether or not the input rotational speed Ne has reached the starting minimum rotational speed Nref (step S300), and the rotational speed Ne has not reached the starting minimum rotational speed Nref. In some cases, the process returns to the process of setting the temporary torque Tm1tmp of the motor MG1 in step S260, and the processes of steps S260 to S300 are repeated until the rotation speed Ne of the engine 22 reaches the minimum start rotation speed Nref. At this time, the battery voltage Vb of the battery 50 may drop and fall below the lower limit voltage Vmin due to the torque output from the motor MG1, but the output torque from the motor MG1 is Since it is limited only by the torque limit Tm1max set based on the output limit Wout of the battery 50 set by the battery temperature Tb and the remaining capacity (SOC), it is not limited by the drop in the battery voltage Vb. The rotational speed Ne reaches the starting minimum rotational speed Nref. As described above, since the output torque from the motor MG1 is not limited by the drop in the battery voltage Vb, the state in which the battery voltage Vb becomes lower than the lower limit voltage Vmin may continue and the battery 50 may be deteriorated. Since it is a short time until the rotational speed Ne of 22 reaches the starting minimum rotational speed Nref, the degree of deterioration is small.

  When the rotational speed Ne of the engine 22 reaches the minimum starting rotational speed Nref, a control signal for starting fuel injection control and ignition control is transmitted to the engine ECU 24 to start fuel injection and ignition (step S310). Is confirmed (step S320), and the cold start control routine is terminated. FIG. 9 shows an example of temporal changes in the output torque Tm1 of the motor MG1 and the rotational speed Ne of the engine 22 when the engine 22 is restarted. As shown in the figure, the engine 22 is started by starting fuel injection and ignition when the rotational speed Ne of the engine 22 reaches the minimum starting rotational speed Nref.

  While the processing of steps S100 to S180 was repeated, the engine speed Ne reached the minimum engine speed Nref and fuel injection and ignition started, but the scheduled start time had elapsed before the complete explosion. Sometimes, the engine 22 is restarted in steps S220 to S320.

  According to the hybrid vehicle 20 of the embodiment described above, since a sufficient torque cannot be output from the motor MG1 due to the voltage correction of the output limit Wout of the battery 50 when it is cold, the start of the engine 22 is started. If the rotational speed Ne of the engine 22 does not reach the minimum starting rotational speed Nref before the scheduled start time elapses, the engine 22 is started at the minimum even when it is cold based on the output limit Wout of the battery 50 at that time. Regardless of the fact that the battery voltage Vb becomes less than the lower limit voltage Vmin by outputting from the motor MG1 the torque limited by the torque limit Tm1max set as a torque larger than the torque required to rotate at the rotation speed Nref or higher. Because cranking the engine 22 and starting the engine 22, It is possible to start the engine 22 more reliably during between. In other words, the engine 22 can be started even if the engine 22 fails to start when it is cold. Thereby, the battery 50 can be charged using the power from the engine 22.

  In the hybrid vehicle 20 of the embodiment, when the engine 22 cannot be started due to voltage correction of the output limit Wout of the battery 50 or the like, the engine 22 is started at the lowest speed even when it is cold based on the output limit Wout of the battery 50 at that time. Torque limit Tm1max is set as a torque larger than the torque required to rotate at several Nref or more, and temporary torque Tm1tmp derived from the torque map at the start of engine 22 is limited by set torque limit Tm1max. The engine 22 is cranked by setting the torque command Tm1 *. However, when the engine 22 cannot be started due to voltage correction of the output limit Wout of the battery 50, etc., it is related to the output limit Wout of the battery 50 at that time. Without engine 2 even when cold The torque limit Tm1max is set to a predetermined torque larger than the torque required to rotate the engine at the minimum start speed Nref, and the temporary torque Tm1tmp derived from the torque map at the start of the engine 22 is set to the torque limit Tm1max. Then, the engine 22 may be cranked by setting the torque command Tm1 * of the motor MG1, or when the engine 22 cannot be started due to voltage correction of the output limit Wout of the battery 50, the battery 50 at that time Regardless of the output limit Wout, the engine 22 is cranked by directly setting a torque larger than the torque required to rotate the engine 22 at the starting minimum rotational speed Nref or more as the torque command Tm1 * of the motor MG1. Also good.

  In the hybrid vehicle 20 of the embodiment, when the engine 22 is started in the cold state, the output limit Wout of the battery 50 is controlled by feedback control so that the battery voltage Vb becomes the lower limit voltage Vmin when the battery voltage Vb is less than the lower limit voltage Vmin. Voltage correction different from voltage correction by feedback control of the output limit Wout, for example, voltage correction for reducing the output limit Wout of the battery 50 by a predetermined power ΔW when the battery voltage Vb is less than the lower limit voltage Vmin. It is good also as what performs. Further, the voltage correction of the output limit Wout of the battery 50 may not be performed.

  In the hybrid vehicle 20 of the embodiment, when the engine 22 is started in the cold state, the fuel injection control and the ignition control are started when the rotational speed Ne of the engine 22 reaches the minimum starting rotational speed Nref. The fuel injection control or the ignition control may be started when the rotational speed Ne of 22 reaches a rotational speed slightly larger than the minimum starting rotational speed Nref.

  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 changed by the reduction gear 35 and output to the ring gear shaft 32a. However, as illustrated in the hybrid vehicle 120 of the modification of FIG. May be connected to an axle (an axle connected to the wheels 64a and 64b in FIG. 10) 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 embodiment, the hybrid vehicle 20 is configured. However, if the vehicle includes an engine, an electric motor capable of cranking the engine, and a secondary battery that supplies electric power to the electric motor, the above-described cold start control is applied. It can be any car. In addition, the present invention is not limited to those applied to automobiles, and is not limited to those applied to automobiles, but is incorporated into non-moving equipment such as forms of power output devices mounted on moving bodies such as vehicles, ships, and aircraft, and construction equipment. An output device may be used. Furthermore, it is good also as a form of the control method of such a power output device.

  Here, 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 corresponds to the “internal combustion engine”, the motor MG1 corresponds to the “electric motor”, the battery 50 corresponds to the “secondary battery”, and the charge / discharge current Ib detected by the current sensor 51b is integrated. Battery ECU 52 and battery voltage for calculating input / output limits Win and Wout, which are the maximum allowable power that may charge / discharge battery 50 based on the remaining capacity (SOC) of battery 50 based on the value and battery temperature Tb of battery 50 The hybrid electronic control unit 70 that corrects the voltage of the output limit Wout based on Vb corresponds to an “output limit setting means”. When the engine 22 is started in the cold state, the motor MG1 operates within the corrected range. A torque command Tm1 * of the motor MG1 is set so as to crank the engine 22, and is transmitted to the motor ECU 40 and is When the start control in steps S100 to S210 in FIG. 5 for transmitting a control signal for starting the fuel injection control and the ignition control to the engine ECU 24 is executed, and the engine 22 cannot be started by such start control, the battery 50 at that time Torque command Tm1 of motor MG1 is set to a torque within a range of torque limit Tm1max set as a torque larger than the torque required for rotating engine 22 at the starting minimum rotational speed Nref or higher based on the output limit Wout. * Is set and transmitted to the motor ECU 40 and the control signal for starting fuel injection control and ignition control is transmitted to the engine ECU 24. The hybrid electronic control unit 70 for executing the processing of steps S240 to S320 in FIG. 5 and the torque command Tm1. * Is received and motor MG1 is driven and controlled Rukoto by the engine ECU24 for receiving a control signal for starting the motor ECU40 and the fuel injection control and ignition control of the engine 22 to crank for controlling the fuel injection and ignition of the engine 22 corresponds to "start control means". Further, the power distribution and integration mechanism 30 corresponds to a “3-axis power input / output unit”, and the motor MG2 corresponds to a “second electric motor”. 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 “motor” is not limited to the motor MG1 configured as a synchronous generator motor, and may be any type of motor as long as it is used for cranking an internal combustion engine, such as an induction motor. The “secondary battery” is not limited to the battery 50 configured as a lithium ion secondary battery, and may be a secondary battery having any configuration such as a nickel hydride secondary battery or a lead storage battery. As the “output limit setting means”, the battery 50 is charged / discharged based on the remaining capacity (SOC) of the battery 50 based on the integrated value of the charge / discharge current Ib detected by the current sensor 51b and the battery temperature Tb of the battery 50. It is not limited to calculating the input / output limits Win and Wout, which are the maximum allowable powers, and correcting the output limit Wout based on the battery voltage Vb. The remaining capacity (SOC) and the battery temperature Tb In addition, for example, the output limit Wout is calculated based on the internal resistance of the battery 50 and the battery temperature Tb and the output limit Wout is corrected based on the battery voltage Vb. Set the output limit that is the maximum allowable discharge power that can be discharged from the secondary battery based on the state of the secondary battery including the output voltage of It may be used as any of those, if any. The “starting time control means” is not limited to the combination of the hybrid electronic control unit 70, the engine ECU 24, and the motor ECU 40, and may be configured by a single electronic control unit. Further, the “starting control means” is a start for starting the engine 22 by controlling the motor MG1 so that the motor MG1 is cranked by the motor MG1 within the voltage-corrected range when the engine 22 is started in the cold state. When the engine 22 cannot be started with such start control, it is necessary to rotate the engine 22 at the start minimum rotational speed Nref or more even in the cold state based on the output limit Wout of the battery 50 at that time. However, the present invention is not limited to the one in which the torque within the range of the torque limit Tm1max set as the torque larger than the normal torque is output from the motor MG1 and the engine 22 is cranked to start the engine 22; , Regardless of the output limit Wout of the battery 50 at that time A predetermined torque larger than the torque required to rotate the engine 22 at the starting minimum rotational speed Nref or higher is output from the motor MG1 to start the engine 22 by cranking the engine 22 or when the engine 22 is cold When starting, voltage correction is performed to reduce the output limit Wout of the battery 50 by a predetermined power ΔW when the battery voltage Vb is less than the lower limit voltage Vmin, and the engine 22 is closed by the motor MG1 within the range of the output-corrected output limit Wout. When the internal combustion engine is instructed to start when it is cold, such as ranking, the internal combustion engine is cranked by driving the motor within the range of the output limit of the secondary battery. The normal start control is performed to control the internal combustion engine and the electric motor to start. When the internal combustion engine cannot be started even when the time start control is executed, the internal combustion engine is cranked to start the internal combustion engine by driving the electric motor regardless of the output limit of the secondary battery. As long as it controls the motor and the electric motor, it may be anything. The “three-axis power input / output means” is not limited to the power distribution / integration mechanism 30 described above, but includes four or more shafts using a double pinion type planetary gear mechanism or a combination of a plurality of planetary gear mechanisms. Connected to the three shafts of the drive shaft, the output shaft of the internal combustion engine, and the rotating shaft of the motor, such as those connected to the motor or those having a different operation action from the planetary gear such as a differential gear. As long as the power is input / output to / from the remaining shafts based on the power input / output to / from the two shafts, any configuration may be used. 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. Absent. 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. It is an example for specifically explaining the best mode for doing so, and does not limit the elements of the invention described in the column of means for solving the problem. In other words, the interpretation of the invention described in the column of means for solving the problem 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 problem. It is only a specific example.

  The best mode for carrying out the present invention has been described with reference to the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the gist of the present invention. Of course, it can be implemented in the form.

  The present invention can be used in the power output apparatus and 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 explanatory drawing which shows an example of the relationship between the battery temperature Tb in the battery 50, and the input / output restrictions Win and Wout. It is explanatory drawing which shows an example of the relationship between the remaining capacity (SOC) of the battery 50, and the correction coefficient of input / output restrictions Win and Wout. It is a flowchart which shows an example of the cold start control routine performed by the hybrid electronic control unit 70 of the embodiment. It is explanatory drawing which shows an example of the torque map at the time of setting the torque which should be output from motor MG1 at the time of engine 22 start, and an example of the mode of the rotation speed Ne of the engine 22. FIG. It is explanatory drawing which shows an example of the time change of the output torque Tm1 of the motor MG1 and the rotation speed Ne of the engine 22 when the rotation speed Ne of the engine 22 does not reach the start minimum rotation speed Nref before the scheduled start time elapses. . It is explanatory drawing which shows an example of the map for torque limitation settings. It is explanatory drawing which shows an example of the time change of the output torque Tm1 of the motor MG1 at the time of restarting the engine 22, and the rotation speed Ne of the engine 22. 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, 51a voltage sensor, 51b current sensor, 51c Temperature sensor, 52 Battery electronic control unit (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 89 Air temperature 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 Capacitors, 148 air flow meter, 149 temperature sensor, 150 a variable valve timing mechanism, 230 pair-rotor motor, 232 an inner rotor, 234 outer rotor, MG1, MG2 motor.

Claims (6)

A power output device that outputs power to a drive shaft,
An internal combustion engine used to output power to the drive shaft;
An electric motor used for cranking the internal combustion engine;
A secondary battery for supplying electric power to the electric motor;
An output limit setting means for setting an output limit that is an allowable maximum discharge power that can be discharged from the secondary battery based on a state of the secondary battery including a temperature of the secondary battery and an output voltage of the secondary battery; ,
The internal combustion engine is configured to crank the internal combustion engine and start the internal combustion engine by driving the electric motor within the set output limit range when an instruction to start the internal combustion engine is issued in the cold state. A normal start control for controlling the motor is executed, and when the internal combustion engine cannot be started even if the normal start control is executed, the motor is driven regardless of the set output limit. Start control means for controlling the internal combustion engine and the electric motor to crank the internal combustion engine to start the internal combustion engine,
A power output device comprising:   The output restriction setting means is a means for setting the output restriction such that when the output voltage of the secondary battery is less than a predetermined lower limit voltage, the larger the difference between the output voltage and the predetermined lower limit voltage, the smaller the output voltage. The power output apparatus according to claim 1.   If the internal combustion engine cannot be started even when the normal start control is executed, the start time control means sets the output restriction set by the output restriction setting means when starting cranking again. The internal combustion engine and the electric motor so as to crank the internal combustion engine and start the internal combustion engine by continuously outputting from the electric motor a torque required to start the internal combustion engine set based on The power output apparatus according to claim 1, wherein the power output apparatus is a means for controlling the power. The power output device according to any one of claims 1 to 3,
Connected to the three shafts of the drive shaft, the output shaft of the internal combustion engine, and the rotating shaft of the electric motor, power is applied to the remaining shaft based on the power input / output to / from any two of the three shafts. 3-axis power input / output means for outputting;
A second electric motor capable of inputting and outputting power to the drive shaft;
A power output device comprising:   A vehicle comprising the power output device according to any one of claims 1 to 4 and an axle connected to the drive shaft. An internal combustion engine used to output power to the drive shaft; an electric motor used for cranking the internal combustion engine; a secondary battery for supplying electric power to the electric motor; a temperature of the secondary battery; and an output of the secondary battery Output limit setting means for setting an output limit that is an allowable maximum discharge power that can be discharged from the secondary battery based on a state of the secondary battery including a voltage, and a control method for a power output device comprising:
When an instruction to start the internal combustion engine is issued in the cold state, the internal combustion engine is cranked by driving the electric motor within the range of the output limit set by the output limit setting means, and the internal combustion engine is started. When the normal time start control for controlling the internal combustion engine and the electric motor is executed, and the normal time start control is not executed, the internal combustion engine cannot be started. Controlling the internal combustion engine and the electric motor to start the internal combustion engine by cranking the internal combustion engine by driving the electric motor regardless of output restriction;
A control method for a power output apparatus.

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