JP2013252767A - Drive device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve operability by expanding a motor generator mechanically coupled with an output shaft of an engine through a belt to the torque assist during the vehicle traveling.SOLUTION: A drive device of a vehicle includes: a motor generator 21 mechanically connected with an output shaft of an engine 2 through a belt; a motor driving torque setting means 51 that sets the motor driving torque when starting the engine 2 by the motor generator 21 and the motor driving torque when assisting the torque of the engine 2 to different values; and a motor generator control means 51 that drives the motor generator 21 to generate the set motor driving torque.

Description

  The present invention relates to a vehicle drive device.

  A technique is known in which a motor generator is mechanically coupled to an output shaft of an engine via a belt, and the engine is started by the motor generator (see Patent Document 1).

JP 2007-292079 A

  By the way, the present inventor has conceived that drivability is improved if the range in which the motor generator is used is not limited to engine starting but can be extended to torque assist during vehicle travel.

  However, the technique of Patent Document 1 only considers the case where the motor generator is used for starting the engine, and does not describe any design / control method of the motor generator when it is expanded to torque assist while the vehicle is running. Absent.

  An object of the present invention is to provide a device that improves the drivability by expanding the motor generator to torque assist during vehicle travel.

  The vehicle drive device according to the present invention includes a motor drive torque when the engine is started by a motor generator mechanically coupled to the output shaft of the engine via a belt, and a motor drive torque when torque assisting the engine. Set to a different value.

  According to the present invention, the engine start torque and the engine assist torque by the motor generator mechanically coupled to the engine output shaft via the belt can be set to appropriate values, respectively, and appropriate control can be performed. it can.

FIG. 1 is a schematic configuration diagram of a vehicle drive device according to the first embodiment. FIG. 2 is a control system diagram of the gasoline engine. FIG. 3 is a flowchart of drive control of the motor generator performed by the vehicle drive device in the first embodiment. FIG. 4 is a flowchart of motor generator drive control performed by the vehicle drive apparatus according to the second embodiment. FIG. 5 is a flowchart of drive control of the motor generator performed by the vehicle drive apparatus in the third embodiment. FIG. 6 is a flowchart of motor generator drive control performed by the vehicle drive apparatus according to the third embodiment.

-First embodiment-
FIG. 1 is a schematic configuration diagram of a vehicle drive device according to the first embodiment. In FIG. 1, a vehicle 1 is provided with an engine 2, a motor generator 21, and an air conditioner compressor 31. Specifically, the output shaft 3 of the engine 2, the rotating shaft 22 of the motor generator 21, and the rotating shaft 32 of the air conditioner compressor 31 are arranged in parallel, and the crank pulley 4 is connected to the rotating shafts 22 and 32 at one end of the output shaft 3. The pulleys 23 and 33 are attached to each other. A belt 5 is wound around each of the three pulleys 4, 23, and 33, and power is transmitted (conducted) between the output shaft 3 and the rotary shafts 23 and 33 of the engine 2 by the belt 5.

  The starter 6 is used for starting the engine 2. A torque converter 8 and a belt type automatic transmission 9 are connected to the other end of the output shaft 3 of the engine 2. The torque converter 8 has a pump impeller and a turbine runner (not shown). The belt-type automatic transmission 9 includes a primary pulley and a secondary pulley (not shown) and a steel belt that is wound around these pulleys. The rotational driving force of the engine 2 is finally transmitted to vehicle drive wheels (not shown) via the torque converter 8 and the automatic transmission 9.

  As a power source for the vehicle 1, a main battery 41 and a sub battery 42 are provided. Both are 14V batteries. The two batteries 41 and 42 are connected by two relays 43 arranged in parallel.

  The starter 6 and the motor generator 21 are connected between the main battery 41 and the relay 43, and power is supplied from the main battery 41. Since motor generator 21 is composed of an AC machine, inverter 24 for converting DC from main battery 41 to AC is attached.

  The engine control module (ECM) 51 controls the engine 2, the starter 6, and the motor generator 21.

  FIG. 2 is a control system diagram of the gasoline engine. Each intake port (not shown) is provided with a fuel injection valve 7. The fuel injection valve 7 supplies fuel to the engine 2 intermittently.

  The intake passage 11 is provided with an electronically controlled throttle valve 12, and an opening degree of the throttle valve 12 (hereinafter referred to as “throttle opening degree”) is controlled by a throttle motor 13. The actual throttle opening is detected by the throttle sensor 14 and input to the engine control module 51.

  The engine control module 51 receives an accelerator opening signal (amount of depression of the accelerator pedal 52) from the accelerator sensor 53, a crank angle signal from the crank angle sensor 54, and an intake air amount signal from the air flow meter 55. The From the signal of the crank angle sensor 54, the rotational speed of the engine 2 is calculated. The engine control module 51 calculates the target intake air amount and the target fuel injection amount based on these signals, and the throttle motor 13 and each fuel injection valve 7 so as to obtain the target intake air amount and the target fuel injection amount. Command.

  Here, the control of the intake air amount will be outlined (refer to Japanese Patent Laid-Open No. 9-287513). By searching a predetermined map from the accelerator opening APO and the engine speed Ne, the target basic intake air amount and the target equivalent ratio tDML are respectively calculated. A value obtained by dividing the target basic intake air amount by the target equivalent ratio tDML is set as the target intake air amount. The target throttle valve opening is obtained by searching a predetermined map from the target intake air amount and the engine speed. The target throttle valve opening is converted into a command value and output to the throttle motor 13.

Next, control of fuel injection (fuel injection amount and fuel injection timing) will be outlined. The output of the air flow meter 55 is A / D converted and linearized to calculate the intake air amount Qa. From this intake air amount Qa and the engine speed Ne, the basic injection pulse width Tp0 [ms] that provides an air-fuel mixture with a substantially stoichiometric air-fuel ratio (equivalent ratio = 1.0) is expressed as Tp0 = K × Qa / Ne (where K is determined as a constant). next,
Tp = Tp0 × Fload + Tp−1 × (1−Fload)
Where Fload: weighted average coefficient,
Tp-1: Previous Tp,
The cylinder air amount equivalent pulse width Tp [ms] is obtained by the following equation. This is because the air amount flowing into the cylinder (combustion chamber) (that is, the cylinder air amount) has a response delay with respect to the intake air amount in the air flow meter section, and this response delay is approximated by a primary delay. The weighted average coefficient Fload [nameless number] which is a coefficient of the first order lag is obtained by searching a predetermined map from the product Ne · V of the rotational speed Ne and the cylinder volume V and the total flow path area Aa of the intake pipe. Based on the cylinder air amount equivalent pulse width Tp thus determined, the fuel injection pulse width Ti [ms] given to the fuel injection valve 7 is
Ti = Tp × tDML × (α + αm−1) × 2 + Ts
However, tDML: target equivalent ratio [anonymous number],
α: Air-fuel ratio feedback correction coefficient [anonymous number]
αm: Air-fuel ratio learning value [anonymous number]
ts: invalid injection pulse width [anonymous number],
It is calculated by the following formula. When the predetermined fuel injection timing comes, the fuel injection valve 7 is opened for the period of this fuel injection pulse width Ti.

  The gasoline engine 2 includes a spark plug facing the combustion chamber (cylinder). The engine control module 51 generates a spark in the spark plug by cutting off the primary current of the ignition coil at a predetermined time before the compression top dead center, thereby igniting the air-fuel mixture in the combustion chamber.

  When the engine control module 51 determines that there is an initial start request based on a signal from the starter switch 56, the engine control module 51 drives the starter 6 to start the engine 2.

  The engine control module 51 performs idle stop control for the purpose of improving fuel consumption. That is, when the accelerator pedal 52 is not depressed (APO = 0), the brake pedal 57 is depressed (the brake switch 58 is ON), and the vehicle 1 is in a stopped state (vehicle speed VSP = 0), the idle stop is performed. The permission condition is satisfied. When the idle stop permission condition is satisfied, the fuel injection from the fuel injection valve 7 to the intake port is shut off, and the engine 2 is stopped. Thereby, useless fuel consumption is reduced.

  Thereafter, when the accelerator pedal 52 is depressed or the brake pedal 57 is returned (the brake switch 58 is OFF) in the idle stop state, the idle stop permission condition is not satisfied. If the idle stop permission condition is not satisfied, the engine 2 is cranked using the motor generator 21 as a starter, the fuel injection from the fuel injection valve 7 and the spark ignition by the spark plug are restarted, and the engine 2 is restarted. .

  Thus, by using the motor generator 21 exclusively for engine restart from idle stop, the use frequency of the starter 6 is reduced and the starter 6 is protected. When the starter 6 and the motor generator 21 are driven, the engine control module 51 cuts off both the two relays 43 to electrically disconnect the main battery 41 and the sub battery 42. This prevents the voltage of the sub-battery 42 from fluctuating with the starting operation of the engine 2.

  Returning to FIG. 1, the description will be continued. The vehicle 1 is provided with an automatic transmission control unit (CVTCU) 61. The automatic transmission control unit 61 controls the gear ratio of the automatic transmission 9 in a stepless manner according to the vehicle running conditions determined from the vehicle speed and the throttle opening. The torque converter 8 having a pump impeller and a turbine runner is provided with a mechanical lockup clutch for fastening and releasing the pump impeller and the turbine runner. The travel range of the vehicle that engages the lockup clutch is predetermined as a lockup region (vehicle speed and throttle opening are used as parameters). The automatic transmission control unit 61 engages the lock-up clutch to directly connect the engine 2 and the transmission 9 when the vehicle driving condition is in the lock-up region, and the vehicle driving condition is not in the lock-up region. Sometimes the lockup clutch is released. When the engine 2 and the transmission 9 are in a directly connected state, the torque converter 8 does not absorb the torque, and the fuel efficiency is improved accordingly.

  The vehicle 1 also includes a vehicle dynamics control unit (VDCCU) 62, a vehicle speed sensitive electric power steering control unit (EPSCU) 63, an air conditioner auto amplifier 64, and a combination meter 66. Is provided. When the vehicle dynamic control unit 62 is about to cause a side slip or a tail swing of the vehicle, the sensor detects a side slip state, and improves vehicle stability during traveling by brake control and engine output control. The vehicle speed sensitive electric power steering control unit 63 outputs an optimum assist torque signal to the EPS motor from the steering torque input from the torque sensor and the vehicle speed.

  The automatic transmission control unit 61, the vehicle dynamic control unit 62, the vehicle speed sensitive power steering control unit 63, and the combination meter 66 are electric loads that cannot tolerate a voltage drop. Therefore, these are supplied with power from the sub-battery 42.

  The engine control module 51 and each of the three control units 61 to 63, an air conditioner auto amplifier (A / C Amp) 64, and a combination meter 66 are connected by a CAN (Controller Area Network). A vehicle speed signal is input from the combination meter 66 to the engine control module 51.

  Here, the present inventor has conceived that drivability is improved if the range in which the motor generator 21 is used can be expanded not only for engine start but also for torque assist during vehicle travel. Therefore, in the vehicle drive device according to the present embodiment, the use range of the motor generator 21 used for restarting from the idle stop is extended to torque assist during vehicle travel.

  When permitting torque assist, the main battery 41 is used as a power source so that the engine 2 is torque-assisted, and a predetermined assist torque is generated in the motor generator 21. When torque assist is prohibited, no assist torque is generated. As a result, after the engine 2 is started and the vehicle 1 starts to travel, good acceleration response (driability) is obtained.

  The voltage of the main battery 41 is monitored and input to the engine control module 51. The engine control module 51 calculates the SOC (State Of Charge) of the main battery 41 based on the current of the main battery 41 and manages the charge / discharge balance of the main battery 41 based on this SOC.

  The inverter 24 and the engine control module 51 are connected by a LIN (Local Internet Network). Via the LIN, the engine control module 51 instructs the inverter 24 whether to drive the motor generator 21 or to generate electric power with the motor generator 21 or how much current to flow to drive the motor.

  Here, if the motor torque at the time of restarting the engine 2 by the motor generator 21 and the motor torque at the time of torque assisting the engine 2 are made the same magnitude, the torque at the time of restarting the engine 2 becomes inappropriate. Or the torque at the time of assisting the engine 2 may become inappropriate. Therefore, in the present embodiment, the motor torque when the motor 2 is restarted by the motor generator 21 and the motor torque when the engine 2 is torque-assisted are set to different appropriate values.

  FIG. 3 is a flowchart of drive control of the motor generator 21. The process of the flowchart shown in FIG. 3 is performed by the engine control module 51 every predetermined time (for example, every 10 ms).

  In step S10, it is determined whether or not the engine 2 has been started for the first time. The starter 6 is used for the initial start of the engine 2. If it is determined that the engine 2 has not been started for the first time, the current process ends. If it is determined that the engine 2 has not been started, the process proceeds to step S20.

  In step S20, it is determined whether or not the drive condition for the motor generator 21 is satisfied. If it is determined that the drive condition of the motor generator 21 is not satisfied, the current process is terminated. If it is determined that the drive condition is satisfied, the process proceeds to step S30.

  In step S30, it is determined whether or not the established drive condition of the motor generator 21 is a torque assist execution condition of the engine 2. If it is determined that the established drive condition of the motor generator 21 is a torque assist execution condition of the engine 2, the process proceeds to step S40, and if it is determined that the engine 2 is a restart condition, the process proceeds to step S50.

  In step S40, drive torque TSSG of motor generator 21 is set to TRQ1.

  On the other hand, in step S50, drive torque TSSG of motor generator 21 is set to TRQ2 smaller than TRQ1.

  That is, the motor drive torque TSSG when the engine 2 is restarted is made smaller than the motor drive torque TSSG when the engine 2 is torque-assisted. Thus, when the engine 2 is restarted by the motor generator 21, the belt 5 can be protected by preventing belt slip from occurring when the belt 5 is switched from the stationary state to the driving state. Further, when the motor generator 21 assists the torque of the engine 2, a large assist torque can be generated to achieve smooth acceleration.

  In step S <b> 60, a current amount necessary for the motor generator 21 to output the set drive torque TSSG is determined, and a command is issued to the inverter 24 so that the determined current amount flows to the motor generator 21. Based on this command, inverter 24 adjusts the amount of current flowing through motor generator 21. Thereby, motor generator 21 generates drive torque TSSG.

  As described above, according to the vehicle drive device of the first embodiment, the motor drive torque when the engine 2 is started by the motor generator 21 mechanically coupled to the output shaft of the engine 2 via the belt 5; The motor driving torque for assisting the engine 2 is set to a different value, and the motor generator 21 is driven so as to generate the set motor driving torque. As a result, when the motor generator 21 restarts the engine 2 and performs torque assist of the engine 2, it is possible to appropriately generate torques of appropriate magnitudes.

  In particular, according to the vehicle drive device of the first embodiment, the motor drive torque when starting the engine is set so as to be smaller than the motor drive torque when torque assisting the engine. When starting, the belt 5 can be protected by preventing belt slip from occurring when the belt 5 is switched from a stationary state to a driving state. Further, during the torque assist of the engine 2, a large assist torque can be generated to achieve smooth acceleration.

-Second Embodiment-
FIG. 4 is a flowchart of drive control of the motor generator 21 performed by the vehicle drive apparatus in the second embodiment. Steps in which the same processing as that in the flowchart shown in FIG. 3 is performed are denoted by the same reference numerals, and detailed description thereof is omitted.

  If it is determined in step S30 that the established driving condition of the motor generator 21 is a torque assist execution condition of the engine 2, the process proceeds to step S100, and if it is determined that the engine 2 is a restart condition, the process proceeds to step S130. In step S130, drive torque TSSG of motor generator 21 is set to TRQ5.

  In step S100, it is determined whether or not the accelerator opening APO is smaller than a predetermined opening Aa. If it is determined that the accelerator opening APO is smaller than the predetermined opening Aa, the process proceeds to step S110, and if it is determined that the accelerator opening APO is equal to or larger than the predetermined opening Aa, the process proceeds to step S120.

  In step S110, drive torque TSSG of motor generator 21 is set to TRQ3.

  On the other hand, in step S120, drive torque TSSG of motor generator 21 is set to TRQ4.

Between the three driving torques TRQ3, TRQ4, and TRQ5, the relationship of the following expression (1) is established.
TRQ3 <TRQ5 <TRQ4 (1)

  That is, as in the first embodiment, the motor driving torque TSSG (TRQ5) when the engine 2 is restarted is smaller than the motor driving torque TSSG (TRQ4) when the engine 2 is torque assisted. During torque assist, the motor drive torque TSSG (TRQ3) when the accelerator opening APO is smaller than the predetermined opening Aa is made smaller than the motor drive torque TSSG (TRQ5) when the engine 2 is restarted. When the accelerator opening is small, it is considered that the driver desires torque assist for as long a time as possible rather than a large acceleration. If the driving torque TSSG is increased during torque assist, the amount of charge of the main battery 41 is reduced quickly, and the torque assist time is shortened. However, when the accelerator opening is small, the driving torque TSSG is reduced to reduce the driving amount. Torque assist time can be kept long with torque.

  As described above, according to the vehicle drive device of the second embodiment, the motor drive torque when starting the engine is set to be smaller than the motor drive torque when torque assisting the engine. In addition, when the accelerator opening is smaller than the predetermined opening, the motor driving torque for torque assist is set to be smaller than the motor driving torque for starting the engine. Thereby, when the accelerator opening is small, long-time torque assist can be realized with a small torque assist amount.

-Third embodiment-
In the vehicle drive device according to the second embodiment, when the accelerator opening is smaller than a predetermined opening at the time of torque assist of the engine 2, the motor drive torque TSSG at the time of torque assist of the engine 2 is calculated when the engine 2 is restarted. It was made smaller than the motor drive torque TSSG. In the vehicle drive device according to the third embodiment, when the vehicle speed is lower than a predetermined vehicle speed, the motor drive torque TSSG at the time of torque assist of the engine 2 is made smaller than the motor drive torque TSSG at the time of restart of the engine 2.

  FIG. 5 is a flowchart of drive control of the motor generator 21 performed by the vehicle drive apparatus in the third embodiment. Steps for performing the same processing as the processing in the flowchart shown in FIG. 4 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The process of the flowchart shown in FIG. 5 differs from the process of the flowchart shown in FIG. 4 in the process of step S200. In step S200, it is determined whether or not the vehicle speed V is lower than a predetermined vehicle speed Va. If it determines with the vehicle speed V being lower than the predetermined vehicle speed Va, it will progress to step S110, and if it determines with it being more than the predetermined vehicle speed Va, it will progress to step S120.

  As described above, according to the vehicle drive device of the third embodiment, the motor drive torque for starting the engine is set to be smaller than the motor drive torque for torque assisting the engine. In addition, when the vehicle speed is lower than the predetermined vehicle speed, the motor driving torque for torque assist is set to be smaller than the motor driving torque for starting the engine. As a result, long-time torque assist can be realized with a small torque assist amount at a low vehicle speed at which the driver is expected to desire torque assist for as long as possible rather than a large acceleration.

-Fourth Embodiment-
FIG. 6 is a flowchart of drive control of the motor generator 21 performed by the vehicle drive apparatus in the fourth embodiment. Steps in which the same processing as that in the flowchart shown in FIG. 3 is performed are denoted by the same reference numerals, and detailed description thereof is omitted.

  In step S30, if it is determined that the established drive condition of the motor generator 21 is a torque assist execution condition of the engine 2, the process proceeds to step S300, and if it is determined that the engine 2 is a restart condition, the process proceeds to step S310.

  In step S300, drive torque TSSG of motor generator 21 is set to TRQ6.

  On the other hand, in step S310, drive torque TSSG of motor generator 21 is set to TRQ7 which is larger than TRQ6.

  That is, the motor drive torque TSSG when the engine 2 is restarted is made larger than the motor drive torque TSSG when the engine 2 is torque-assisted. Thereby, the start response at the time of restart of the engine 2 is securable. Further, if the drive torque TSSG is increased during torque assist, the amount of charge of the main battery 41 is reduced quickly and the torque assist time is shortened. However, according to the present embodiment, torque assist is performed with a small drive torque during torque assist. You can keep the time long.

  As described above, according to the vehicle drive apparatus of the fourth embodiment, the motor drive torque when torque assisting the engine is set to be smaller than the motor drive torque when starting the engine. The torque assist time can be kept long. Further, since the engine is started with a large driving torque when the engine is started, it is possible to ensure start response at the time of starting the engine.

  The present invention is not limited to the first to fourth embodiments described above, and various modifications and applications can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 2 ... Engine 5 ... Belt 21 ... Motor generator 51 ... Engine control module (Motor drive torque setting means, motor generator control means)

Claims (6)

A motor generator mechanically coupled to the engine output shaft via a belt;
Motor driving torque setting means for setting a motor driving torque when starting the engine by the motor generator and a motor driving torque when torque assisting the engine to different values;
Motor generator control means for driving the motor generator so as to generate the set motor driving torque;
A vehicle drive device comprising: The vehicle drive device according to claim 1,
The motor driving torque setting means sets the motor driving torque when starting the engine to be smaller than the motor driving torque when torque assisting the engine;
A drive device for a vehicle. The vehicle drive device according to claim 2,
The motor drive torque setting means is configured such that when a predetermined condition is satisfied when torque assisting the engine, the motor drive torque when torque assisting the engine is greater than the motor drive torque when starting the engine. Set it to be smaller,
A drive device for a vehicle. The vehicle drive device according to claim 3,
The predetermined condition is that the accelerator opening is smaller than the predetermined opening.
A drive device for a vehicle. The vehicle drive device according to claim 3,
The predetermined condition is that the vehicle speed is lower than the predetermined vehicle speed.
A drive device for a vehicle. The vehicle drive device according to claim 1,
The motor driving torque setting means sets the motor driving torque when torque assisting the engine to be smaller than the motor driving torque when starting the engine.
A drive device for a vehicle.

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