JP2013252765A - Drive device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive device of a vehicle that makes idle stop and assistance by a motor generator compatible.SOLUTION: A drive device includes: an idle stop control part that stops a drive power source (2) based on a state of a vehicle (1), and starts the drive power source (2) again by rotating a motor generator (21) when there is a driving force request; and a torque assist control part that assists the driving force of the drive power source (2) by driving the motor generator (21) after start of travel of the vehicle (1), and limits the operation of the torque assist control part by execution of the operation of the idle stop control part based on the state of a battery (41).

Description

  The present invention relates to a vehicle drive device.

  In the engine that starts the engine by winding a belt around the crank pulley provided on the crankshaft of the engine and the motor generator pulley provided on the motor generator, the motor generator has an engine function in addition to the alternator function (generator function). Some have a motor function for starting (see Patent Document 1).

  Also, there is a motor that assists engine output by driving such a motor generator when the engine is restarted (see Patent Document 2).

  In addition, when performing engine idle stop, there is a technology that permits idle stop when the SOC of the battery is equal to or greater than a predetermined value (see Patent Document 3).

Japanese Patent No. 4451468 JP 2005-325804 A Japanese Patent No. 4517981

  In recent years, from the viewpoint of improving fuel efficiency, idle stop technology for stopping the engine while the vehicle is stopped has become widespread.

  In addition, as in the prior art, a technique for improving fuel efficiency by driving a motor generator to assist the driving force of an engine is also known.

  Thus, when the motor generator is driven in order to assist the driving force of the engine, the electric power charged in the battery is used. Further, since the motor generator is driven when the engine is started after the idle stop is finished, the battery power is used.

  By the way, since there is an upper limit to the amount of electric power stored in the battery, idling stop and engine driving force assist cannot be executed without limitation. Here, in the prior art, a lower limit value of the SOC of the battery necessary for idling stop is set. However, since coexistence of idling stop and engine assist is not taken into account, there is a problem that idle stop is not performed when the battery power is insufficient due to engine assist, and fuel efficiency is not improved.

  The present invention has been made in view of such problems, and provides a vehicle drive device that can improve fuel efficiency by making both engine idle stop and engine drive force assist by a motor generator compatible. For the purpose.

  According to the present invention, a driving force source for driving a vehicle, a motor generator coupled to an output shaft of the driving force source, a battery for supplying electric power to the motor generator and charging the electric power generated by the motor generator, and driving The present invention is applied to a vehicle drive device including a control device that controls the operation of a force source and the operation of a motor generator.

  In this vehicle driving device, the control device stops the driving force source based on the state of the vehicle, and when there is a driving force request, an idle stop control unit that rotates the motor generator to restart the driving force source; A torque assist control unit that drives the motor generator after the vehicle starts running and assists the driving force of the driving force source. And a drive device performs operation | movement of an idle stop control part based on the state of a battery, and restrict | limits operation | movement of a torque assist control part.

  According to the present invention, since the idling stop for stopping the driving force source is prioritized over the torque assist operation by the motor generator, the consumption of fuel from the driving force source can be suppressed, and the fuel efficiency can be improved. .

It is explanatory drawing which shows the structure of the drive device of the vehicle of embodiment of this invention. It is an engine control system figure of an embodiment of the present invention. It is a timing chart of engine restart of an embodiment of the present invention. It is a flowchart of torque assist control of an embodiment of the present invention. It is a time chart which shows the relationship between SOC of the main battery of embodiment of this invention, and torque assist permission. It is explanatory drawing which shows the relationship between SOC of the main battery and torque assist permission of embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is an explanatory diagram showing a configuration of a drive device for a vehicle 1 according to an embodiment of the present invention.

  The vehicle 1 includes an engine 2, a motor generator 21, and an air conditioner compressor 31.

  The crankshaft 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. A crank pulley 4 is provided at one end of the crankshaft 3, and pulleys 23 and 33 are provided at the rotary shafts 22 and 32, respectively. A belt 5 is wound around the crank pulley 4 and the pulleys 23 and 33, and power is transmitted (conducted) between the crankshaft 3 and the rotary shafts 22 and 33 by the belt 5.

  The engine 2 is provided with a starter 6 used for starting the engine. A belt-type automatic transmission 9 is connected to the other end of the crankshaft 3 of the engine 2 via a torque converter 8.

  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 driving wheels (not shown) via the torque converter 8 and the automatic transmission 9.

  The vehicle 1 includes two batteries of a main battery 41 and a sub battery 42 as power sources. The main battery 41 and the sub battery 42 are both batteries that input and output a voltage of 14V. The main battery 41 and the sub battery 42 are electrically connected by two relays 43 arranged in parallel.

  The starter 6 and the motor generator 21 are electrically connected to the main battery 41, and power is supplied from the main battery 41. The motor generator 21 is composed of an AC electric machine, and the motor generator 21 is provided with an inverter 24 that converts direct current and alternating current with the main battery 41.

  The engine control module (ECM) 51 functions as a control device that controls operations of the engine 2, the starter 6, and the motor generator 21.

  Here, the configuration of the engine 2 will be described with reference to FIG.

  FIG. 2 is a configuration diagram of a control system of the engine 2 that is the gasoline engine according to the embodiment of the present invention.

  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, and four cylinders are illustrated here.

  The intake passage 11 includes an electronically controlled throttle valve 12. The opening of the throttle valve 12 is controlled by a throttle motor 13 (hereinafter referred to as “throttle opening”). The actual throttle opening of the throttle valve 12 is detected by the throttle sensor 14 and input to the ECM 51.

  The ECM 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 ECM 51 calculates the rotational speed (engine rotational speed Ne) of the engine 2 from the signal of the crank angle sensor 54, and calculates the target intake air amount and the target fuel injection amount based on other signals. Then, a command is issued to 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.

  The engine 2 includes a spark plug facing the combustion chamber (cylinder). The ECM 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.

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

  Further, the ECM 51 performs idle stop control for the purpose of improving fuel consumption.

  For example, 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 ECM 51 shuts off the fuel injection from the fuel injection valve 7 to the intake port and stops the engine 2. This reduces wasteful fuel consumption.

  Thereafter, when there is a drive request from the driver such as depression of the accelerator pedal 52 or return of the brake pedal 57 (the brake switch 58 is OFF) in the idle stop state, the idle stop permission condition is not satisfied. At this time, the ECM 51 cranks the engine 2 using the motor generator 21 as a starter, restarts fuel injection from the fuel injection valve 7 and spark ignition by the spark plug, and restarts the engine 2.

  Thus, by using the motor generator 21 for starting the engine 2 from the idle stop, the starter 6 is protected by reducing the frequency of use of the starter 6. In this way, the ECM 51 stops the engine 2 and operates the motor generator 21 to restart the engine 2, thereby configuring an idle stop control unit.

  Note that when the starter 6 and the motor generator 21 are driven, the ECM 51 cuts off both of the two relays 33 to electrically disconnect the main battery 41 and the sub battery 42. As a result, the starter 6 and the motor generator 21 are driven by the power of the main battery 41 alone, and the voltage of the sub battery 42 is prevented from fluctuating.

  Returning to FIG. 1, the vehicle 1 includes an automatic transmission control unit (CVTCU) 61.

  The CVTCU 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 lock-up clutch is predetermined as a lock-up region (vehicle speed and throttle opening are used as parameters). In the CVTCU 61, when the vehicle running condition is in the lock-up region, the lock-up clutch is engaged to directly connect the engine 2 and the automatic transmission 9 and when the vehicle running condition is not in the lock-up region, the lock-up clutch is engaged. Open. When the engine 2 and the automatic transmission 9 are directly connected, the torque converter 8 does not absorb the torque, and the fuel efficiency is improved accordingly.

  The vehicle 1 also includes a vehicle dynamic 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.

  The VDCCU 62 includes a sensor, and detects that the vehicle 1 is about to cause a side slip or a bottom swing. In accordance with the skid state, vehicle stability during traveling is improved by brake control and engine output control.

  The EPSCU 63 assists the steering force by outputting an optimum assist torque signal from the torque sensor and the vehicle speed to the EPS motor.

  The CVTCU 61, the VDCCU 62, the EPSCU 63, and the combination meter 66 are electric loads that cannot tolerate a voltage drop. These are supplied with electric power from a sub-battery 42 that can be electrically disconnected from the main battery 41.

  The ECM 51, CVTCU 61, VDCCU 62, EPSCU 63, air conditioner auto amplifier 64, and combination meter 66 are connected by a CAN (Controller Area Network).

  Next, engine driving force assist by the motor generator 21 will be described.

  As described above, after the engine 2 is stopped by the idle stop, when the idle stop permission condition is not satisfied, the ECM 51 drives the motor generator 21 using the main battery 41 as a power source to restart the engine 2. Start.

  After the engine 2 restarts and the vehicle 1 starts running, torque assist using the motor generator 21 is permitted when the engine rotational speed Ne is in a predetermined rotational speed range. When the engine rotational speed Ne deviates from a predetermined rotational speed range while permitting torque assist, torque assist is prohibited.

  When permitting torque assist, the ECM 51 generates a predetermined assist torque in the motor generator 21 using the main battery 41 as a power source so as to torque assist the engine 2. Further, when the torque assist is prohibited, the driving of the motor generator 21 is stopped and the assist torque is not generated. As a result, good acceleration response (driability) can be obtained after the engine 2 is restarted and the vehicle 1 starts running.

  The main battery 41 is provided with a current sensor 49, and the ECM 51 detects the charge / discharge current value of the main battery 41. The ECM 51 performs integration processing based on the charge / discharge current value of the main battery 41 and calculates the SOC (State Of Charge) of the main battery 41. Based on the SOC, the charge / discharge balance of the main battery 41 is managed.

  The inverter 24 and the ECM 51 are connected by a LIN (Local Interconnect Network). Through this LIN, the ECM 51 instructs the inverter 24 whether to drive the motor generator 21 or to generate electric power with the motor generator 21, how much current is passed to drive the motor, and the like.

  The engine 2 and the motor generator 21 have a resonance point of rotational vibration. The resonance point of this rotational vibration exists in a rotational speed region where the engine rotational speed Ne is lower than 1000 rpm, for example. If torque assist is executed in a state where the tension of the belt 5 is low, belt slippage may occur due to the resonance of the rotational vibrations of the engine 2 and the motor generator 21 (in the resonance rotational speed range), and the belt 5 may squeal. is there.

  On the other hand, if the tension of the belt 5 is increased in order to prevent belt slippage due to this resonance, the friction between the crank pulley 4 and the belt 5 increases, resulting in deterioration of fuel consumption. In order to avoid deterioration in fuel consumption due to increased friction between the crank pulley 4 and the belt 5, the belt tension cannot be set high.

  Therefore, in consideration of preventing belt slippage due to resonance, torque assist is performed only in a rotational speed range where the engine rotational speed Ne is higher than, for example, 1000 rpm (first threshold) (medium / high rotational speed range where the motor generator rotational speed is higher than 2600 rpm, for example). To give permission. Torque assist is prohibited when the engine rotational speed Ne is, for example, 1000 rpm (first threshold) or less (a motor generator rotational speed is, for example, a low rotational speed range of 2600 rpm or less).

  After the engine 2 restarts and the vehicle 1 starts running, when the engine speed Ne exceeds the first threshold, the motor generator 21 is driven to perform torque assist. Thus, the torque assist control unit is configured by controlling the motor generator 21 to assist the driving force of the engine 2 after driving of the vehicle 1 is started.

  FIG. 3 shows a timing chart from the start of engine restart according to the embodiment of the present invention.

  FIG. 3 shows changes in time of the engine rotation speed Ne, vehicle torque, vehicle speed VSP, and accelerator opening AOP. The “torque assist permission flag” and the “torque assist execution flag” shown in FIG. 3 will be described with reference to FIG.

  “Vehicle torque” refers to torque used for driving a vehicle, and is usually engine torque. When there is torque assist by the motor generator 21, the sum of the assist torque and the engine torque is the vehicle torque.

  If the idle stop permission condition is not satisfied at timing t1, the ECM 51 drives the motor generator 21 to crank the engine 2 and performs fuel injection from the fuel injection valve 7 and spark ignition by the spark plug. Resume. Thereby, the engine 2 starts combustion and the engine 2 is restarted. The ECM 51 determines that the engine 2 has restarted when the engine rotational speed Ne reaches a predetermined complete explosion rotational speed (timing t2).

  Here, since the driver slightly depresses the accelerator pedal 52 in the vicinity of the timing t2, the engine rotational speed Ne increases and the vehicle torque increases. As a result, the vehicle 1 starts traveling (timing t3).

  In FIG. 3, since the accelerator opening APO is substantially constant even after the vehicle 1 is started, the engine rotational speed Ne and the vehicle torque have substantially constant values after the timing t3.

  Next, it is assumed that the driver greatly depresses the accelerator pedal 52 at timing t5. As the accelerator opening increases, the engine speed Ne increases.

  At this time, when the engine rotation speed Ne exceeds the first threshold value (RPMLK), the ECM 51 determines that the motor generator 21 has left the low rotation speed range. The ECM 51 supplies current from the main battery 41 to the inverter 24 to drive the motor generator 21 as a motor (timing t6).

  After this timing t6, motor torque is added to engine torque, vehicle torque increases, and vehicle speed increases. As a result, the acceleration desired by the driver can be obtained immediately. The torque generated by the motor generator 21 is gradually increased from zero to reach the maximum torque.

  By such control, torque assist at the time of vehicle transmission is executed.

  If an attempt is made to cover the torque assist generated by the motor generator 21 with the torque generated by the engine 2, the fuel supply from the fuel injection valve 7 must be corrected in an increased amount, resulting in increased fuel consumption and poor fuel consumption. In contrast, when the vehicle 1 is decelerated, the motor generator 21 regenerates kinetic energy as electric energy and stores it in the main battery 41. If the engine generator 21 generates assist torque by the electric energy of the main battery 41 when the engine rotational speed Ne exceeds the first threshold value RPMLOK, fuel is not consumed, so that fuel consumption is deteriorated. There is nothing.

  Further, since the motor generator 21 can generate torque more responsively than the engine 2, the driver is prevented from depressing the accelerator pedal too much, and wasteful fuel is not consumed.

  Next, torque assist performed by the ECM 51 will be described with reference to the flowchart of FIG.

  FIG. 4 is a flowchart of torque assist according to the embodiment of the present invention.

  The flowchart shown in FIG. 4 is executed by the ECM 51 at a predetermined cycle (for example, every 10 ms).

  First, the ECM 51 determines whether or not it is after the initial start of the engine 2 in step S1. If the engine 2 is being started for the first time, the starter 6 is used to start the engine, so NO is selected and the processing according to this flowchart ends.

  If it is after the initial start of the engine 2, the process proceeds to step S2, and the ECM 51 determines whether or not it is after the engine 2 is restarted.

  The restart of the engine 2 is a restart of the engine 2 from an idle stop. Since the motor generator 21 restarts the engine 2 from the idle stop, the ECM 51 determines that the engine start from the idle stop has been performed when the motor generator 21 is activated while the vehicle is stopped. If the engine 2 has not been restarted from the idle stop, the processing according to this flowchart is terminated.

  If the engine 2 has been restarted from the idle stop, the process proceeds to step S3.

  In step S3, it is determined whether or not the vehicle 1 is traveling. When the vehicle speed is zero or less than a value close to zero, it is determined that the vehicle is stopped (not running), and the process of this flowchart is terminated.

  If it is determined that the vehicle speed is not zero or exceeds a value close to zero, it is determined that the vehicle is traveling and the process proceeds to step S4.

  In step S4, the ECM 51 determines whether a torque assist permission condition is satisfied.

When the torque assist permission condition is satisfied, it is determined that the torque assist permission condition is satisfied when the following conditions (1) and (2) are not satisfied. In other words, when any one of the following conditions (1) and (2) is satisfied, the torque assist permission condition is not satisfied.
(1) When the lockup clutch is released.
(2) When the SOC of the main battery 41 is less than the torque assist permission threshold.

  Even if an assist torque is applied to the engine 2 when the lockup clutch is released, a part of the assist torque is absorbed by the torque converter 8 and the torque transmission efficiency is poor, so that torque assist is prohibited. If the assist torque is applied to the engine 2 when the lock-up clutch is engaged and the engine 2 and the automatic transmission 9 are directly connected, the assist torque is increased by the vehicle torque. There is no loss of efficiency. Note that the engagement or disengagement of the lockup clutch is determined based on the vehicle speed and the throttle opening as described above.

  Further, when the SOC of the main battery 41 is sufficiently large and is equal to or greater than the torque assist permission threshold value, the ECM 51 permits torque assist.

  If neither of the conditions (1) and (2) is satisfied, it is determined that the torque assist permission condition is satisfied, and the process proceeds to step S5. In step S5, the ECM 51 sets a torque assist permission flag = 1.

  FIG. 3 shows that the torque assist permission flag is switched from zero to 1 at the timing of t4.

  On the other hand, if at least one of the conditions (1) and (2) is satisfied, it is determined that the torque assist permission condition is not satisfied, and the process proceeds to step S6. In step S6, the ECM 51 sets a torque assist permission flag = 0.

  Next, in step S7, it is determined whether the torque assist permission flag is 1. When the torque assist permission flag = 1, the routine proceeds to step 8.

  In step S8, the ECM 51 compares the engine speed Ne [rpm] with the first threshold value RPMLOK [rpm]. The first threshold value RPMLOK is a value that is predetermined as the upper limit of the low rotation speed range of the motor generator 21.

  When the engine rotational speed Ne exceeds the first threshold value RPMLOK, the ECM 51 determines that the motor generator 21 has deviated from the low rotational speed range. At this time, the process proceeds to step S9 to execute torque assist. In step S9, the ECM 51 sets a torque assist execution flag = 1.

  By setting the torque assist execution flag = 1, the ECM 51 supplies current to the inverter 24 to drive the motor generator 21 as a motor.

  FIG. 3 shows that the torque assist execution flag switches from zero to 1 at timing t6. Thereby, motor torque is added to engine torque.

  At this time, the ECM 51 controls the value of the current flowing through the inverter 24 so that the torque generated by the motor generator 21 is gradually increased from zero to reach the maximum torque. This is because if the motor generator 21 generates the maximum torque in a stepwise manner in the low rotation speed region of the engine 2 where it is easy to feel a driving shock, such as when the vehicle starts, a driving shock occurs. Also, when the torque assist is terminated, the value of the current flowing through the inverter 24 is controlled so as to gradually increase from the maximum torque to zero.

  Further, a period during which torque assist is performed (period in which current is passed through the inverter 24) is set to a predetermined time, as will be described later. Since the power consumption of the main battery 41 is accelerated as long as the period during which the torque assist is performed, the time is set so as not to affect the power consumption of the main battery 41.

  If it is determined in step S8 that the engine rotational speed Ne is equal to or lower than the first threshold value RPMLOK, it is determined that the motor generator 21 is in the low rotational speed range, and the process proceeds to step S10. In step S10, the ECM 51 sets a torque assist execution flag = 0.

  By setting the torque assist execution flag = 0, the ECM 51 cuts off the current supply to the inverter 24 and puts the motor generator 21 in a non-driven state.

  In other words, if the driver has obtained the desired acceleration due to acceleration while the vehicle is running, and the engine speed Ne falls below the first threshold RPMLOK by returning the accelerator pedal 52, torque assist is no longer necessary. Then, torque assist execution flag = 0 is set, and torque assist of the motor generator 21 is prohibited.

  As a result, the squealing of the belt 5 in the low rotational speed range of the motor generator 21 is prevented, and the strength of the crankshaft 3 and the rotary shafts 22 and 32 are ensured while at the same time improving fuel efficiency and good acceleration response (drivability). it can.

  If the torque assist permission condition is not satisfied in step S7, the process proceeds to step S10, where the torque assist execution flag = 0 is set.

  By such control, torque assist when the vehicle starts is executed.

  Next, torque assist permission according to the embodiment of the present invention will be described.

  FIG. 5 is a time chart showing the relationship between the SOC of the main battery 41 and the torque assist permission according to the embodiment of the present invention.

  In FIG. 5, the vertical axis represents the accumulated charge amount (SOC) of the battery, and the horizontal axis represents time. Further, the solid line shows the relationship between the torque assist permission and the SOC when the embodiment of the present invention is applied, and the alternate long and short dash line shows the relationship between the torque assist permission and the SOC when the embodiment of the present invention is not applied. Show.

  Note that SOC2 in FIG. 5 is a threshold value of SOC necessary for driving the motor generator 21 and starting the engine 2 after the idle stop condition is canceled. Further, as described later, SOC1 is an SOC threshold value that is a condition for permitting torque assist, and is set to a value larger than SOC2.

  A region less than SOC2 is a third region, a region greater than or equal to SOC2 and less than SOC1 is a second region, and a region greater than SOC1 is a first region.

  After the engine 2 is started and the vehicle 1 starts running, the main battery 41 is charged by the regenerative power of the engine 2 and the electric load 44 is used, so that the power of the main battery 41 is consumed.

  Here, as in the condition (2) described above, when the condition that the SOC of the main battery 41 is less than the torque assist permission threshold is not satisfied, torque assist is permitted. Consider a case where this torque assist permission threshold is set to SOC2 in FIG.

  When the above condition (1) is not satisfied at the timing t11, if the condition (2), that is, the SOC is equal to or higher than the SOC2 that is the torque assist permission threshold, torque assist is permitted. As a result, the motor generator 21 is driven to perform torque assist (indicated by a circle in FIG. 5). The electric power of the main battery 41 is consumed by driving the motor generator 21, and the SOC drops as indicated by the alternate long and short dash line.

  Furthermore, similarly at timing t12, neither of the conditions (1) and (2) is satisfied, and torque assist is permitted. The electric power of the main battery 41 is further consumed by driving the motor generator 21, and the SOC drops as indicated by the alternate long and short dash line.

  Furthermore, similarly at timing t14, neither of the conditions (1) and (2) is satisfied, and torque assist is permitted. The electric power of the main battery 41 is further consumed by driving the motor generator 21, and the SOC drops as indicated by the alternate long and short dash line.

  As a result, at the timing t14, the SOC of the main battery becomes less than SOC2. Thereafter, the torque assist is not executed until the main battery 41 is sufficiently charged until the main battery 41 becomes SOC2 or higher.

  On the other hand, in the present invention, the torque assist permission threshold is set to SOC1 that is larger than SOC2 under the condition (2) in which the SOC of the main battery 41 is less than the torque assist permission threshold. Set.

  In this case, when the above-described condition (1) is not satisfied at timing t11, the condition (2), that is, the SOC is less than the SOC1 that is the torque assist permission threshold value. Is forbidden.

  Thereafter, the main battery 41 is charged by the regenerative power of the engine, and the SOC eventually rises as indicated by the solid line.

  Thereafter, when the condition (1) is not satisfied at the timing t12, the condition (2) is not satisfied, that is, if the SOC is equal to or greater than the SOC1 that is the torque assist permission threshold, torque assist is permitted. As a result, the motor generator 21 is driven to perform torque assist (indicated by □ in FIG. 5). The power of the main battery 41 is consumed by driving the motor generator 21, and the SOC drops as shown by the solid line.

  Thereafter, at timing t13, if the condition (1) is not satisfied and the condition (2) is not satisfied, that is, if the SOC is equal to or greater than SOC1 that is a torque assist permission threshold, torque assist is permitted. The power of the main battery 41 is consumed by driving the motor generator 21, and the SOC drops as shown by the solid line.

  In FIG. 5, when the SOC transition indicated by the alternate long and short dash line is compared with the SOC transition indicated by the solid line, the SOC transition indicated by the solid line maintains a region where the SOC2 is longer than the time (timing t14). To t15). When the SOC of the main battery 41 is SOC2 or more, it is an area where idle stop is possible. By the control of the present invention indicated by the solid line, it is possible to perform idle stop for a longer time, and fuel consumption can be suppressed by the idle stop, and fuel efficiency can be improved.

  The control of FIG. 5 is summarized as an explanatory diagram shown in FIG. When the SOC of the main battery 41 is in the region 3, neither idling stop nor torque assist is permitted. Further, when the SOC of the main battery 41 is in the region 2 that is equal to or higher than SOC1 and lower than SOC2, only idle stop is permitted, and torque assist is not permitted. Further, when the SOC of the main battery 41 is in the region 1 equal to or higher than SOC2, both idle stop and torque assist are permitted.

  By such control, permission of idling stop and permission of torque assist are determined based on the SOC of the main battery 41. More specifically, since the idle stop does not consume fuel, the improvement in fuel efficiency is greater than the torque assist during acceleration. Accordingly, the fuel efficiency can be improved by giving priority to the idling stop.

In FIG. 5, when torque assist is permitted, the torque assist time for driving motor generator 21 is set to a time corresponding to the difference between SOC1 and SOC2. That is, depending on the electric power consumed by motor generator 21 with one torque assist, the time is set such that the SOC of main battery 41 does not become less than SOC2. That is, the torque assist time t is
Set so that t <(SOC1-SOC2) / current consumption during torque assist. With this setting, the motor generator 21 is continuously operated, so that failure due to heating of the motor generator 21 and wear of bearings and the like can be suppressed.

  Also, SOC1 set as the torque assist permission threshold is also set to a value such that the main battery 41 does not become less than SOC2 depending on the electric power consumed by the motor generator 21 with one torque assist.

  Further, regarding the condition (2) that the SOC of the main battery 41 is less than the torque assist permission threshold, a condition that the temperature of the main battery 41 (battery liquid temperature) is low may be added. For example, when the battery liquid temperature of the main battery 41 is lower than a predetermined temperature (for example, 5 ° C.) in a cold district or winter, the charge / discharge performance of the main battery 41 is significantly reduced.

  Therefore, for the purpose of increasing the period during which idling can be stopped without reducing the SOC of the main battery 41, torque assist is not permitted when the temperature of the main battery 41 decreases, and the temperature of the main battery 41 is higher than a predetermined temperature. Control may be made so that torque assist is permitted only when it is high. Thereby, fuel consumption performance is not reduced.

  Further, regarding the condition (2) that the SOC of the main battery 41 is less than the torque assist permission threshold, it is further determined whether or not the deterioration degree of the main battery 41 is progressing, and the deterioration degree is not progressing. You may add the condition.

  The ECM 51 determines the degree of deterioration of the main battery 41 from the state (SOC, voltage, cumulative activation time, etc.) of the main battery 41 at the time of starting. When the deterioration degree of the main battery 41 exceeds a predetermined deterioration degree, the charge / discharge amount of the main battery 41 is limited.

  Therefore, for the purpose of increasing the period during which idling can be stopped without reducing the SOC of the main battery 41, if the deterioration level of the main battery 41 exceeds a predetermined deterioration level, control is performed so that torque assist is not permitted. Good. Thereby, fuel consumption performance is not reduced.

  As described above, in the embodiment of the present invention, the ECM 51 executes the idle stop even when the charge amount (SOC) of the main battery 41 can execute both the idle stop and the torque assist, thereby limiting the torque assist. To control.

  Conventionally, in order to improve fuel consumption, idling stop is generally performed in which the engine 2 is stopped while the vehicle 1 is stopped. Here, in the embodiment of the present invention, in order to further improve the fuel efficiency, the motor generator 21 is controlled not only to restart the engine 2 but also to perform torque assist of the driving force of the engine 2.

  By the way, the electric power of the main battery 41 is consumed by the motor generator 21 for restart from the idle stop. Further, the electric power of the main battery 41 is consumed by the motor generator 21 during torque assist. However, since the power that can be stored in the main battery 41 is limited, it is impossible to perform idle stop and torque assist indefinitely.

  Therefore, in the embodiment of the present invention, as described above, the ECM 51 improves the fuel consumption performance by executing the idling stop that consumes no fuel and has a large effect of improving the fuel consumption performance in preference to the torque assist. be able to.

1 Vehicle 2 Engine 3 Crankshaft 4 Crank Pulley 5 Belt 6 Starter 8 Torque Converter 9 Automatic Transmission 21 Motor Generator 22 Rotating Shaft 23 Pulley 24 Inverter 31 Air Conditioning Compressor 32 Rotating Shaft 41 Main Battery 49 Current Sensor 51 Engine Control Module (ECM) )

Claims (6)

A driving force source for driving the vehicle;
A motor generator coupled to the output shaft of the driving force source;
A battery for supplying electric power to the motor generator and charging the electric power generated by the motor generator;
A control device for controlling the operation of the driving force source and the operation of the motor generator;
With
The controller is
An idle stop control unit that stops the driving force source based on the state of the vehicle, rotates the motor generator when the driving force is requested, and restarts the driving force source;
A torque assist control unit that drives the motor generator after the vehicle starts running and assists the driving force of the driving force source;
The vehicle drive device characterized in that the operation of the idle stop control unit is executed based on the state of the battery and the operation of the torque assist control unit is limited.   2. The vehicle drive device according to claim 1, wherein the control device executes an operation of the torque assist control unit when a charge amount of the battery is larger than a predetermined charge amount.   3. The vehicle drive device according to claim 1, wherein the control device executes an operation of the torque assist control unit when a temperature of the battery is higher than a predetermined temperature. 4.   The vehicle according to any one of claims 1 to 3, wherein the control device executes an operation of the torque assist control unit when a deterioration degree of the battery is smaller than a predetermined deterioration degree. Drive device. The torque assist controller is
After the vehicle starts running, the motor generator is driven,
5. The vehicle drive device according to claim 1, wherein a drive time of the motor generator is limited to a predetermined time. 6. The controller is
When the charge amount of the battery is larger than the first predetermined capacity, the operation of the idle stop control unit is executed,
When the charge amount of the battery is larger than a second predetermined capacity that is larger than the first predetermined capacity, the operation of the torque assist control unit is executed,
The torque assist controller is
6. The vehicle drive device according to claim 5, wherein the predetermined time is a time based on a difference in battery capacity between the first predetermined capacity and the second predetermined capacity.

Images