JPWO2013021504A1 - Control device for hybrid vehicle - Google Patents

Abstract

Provided is a control device for a hybrid vehicle that can expand an electric motor travel region by reducing as much as possible electric energy for starting an engine that is always secured by a power storage device. When starting the engine (12), the electronic control unit (58) does not use the electrical energy stored in the power storage device (57), and the inside of the cylinder in the expansion stroke among the plurality of cylinders provided in the engine (12). Since the rotational speed of the engine (12) is increased by directly injecting and exploding the fuel, it is necessary to always secure the electric energy for starting the engine (12) in the power storage device using the electric motor MG. Less. For this reason, it is not necessary to set the ratio of the electric energy that can be used for the electric motor travel to be small by the electric energy required for starting the engine (12). Therefore, it is not necessary to make it smaller, and the electric motor traveling area can be expanded, and the fuel efficiency of the vehicle can be improved.

Description

  The present invention relates to a control apparatus for a hybrid vehicle provided with a clutch in a power transmission path between an engine and an electric motor, and more particularly to a technique for improving fuel efficiency by expanding an electric motor traveling region that travels using the electric motor as a driving force source. .

  As one type of hybrid vehicle, a drive device for a hybrid vehicle having a clutch in a power transmission path between an engine and an electric motor is known. In this hybrid vehicle, at least one of the engine and the electric motor can be selectively used as a driving source for traveling. In general, when the vehicle is running at a low vehicle speed and at a low load, the motor is driven exclusively by using the motor as a drive source by separating the engine by releasing the clutch. The engine running used as the drive source is selected. For example, this is a hybrid vehicle described in Patent Document 1 and Patent Document 2.

  According to this, on the low load side where the efficiency of the engine cannot be sufficiently obtained, the fuel consumption of the vehicle can be improved by running the electric motor using the electric energy stored by the power storage device. In particular, it is desirable to increase the proportion of electric motor travel.

Japanese Patent Laid-Open No. 11-082260 JP 2004-204963 A

  By the way, the electric vehicle traveling of the hybrid vehicle is realized by consuming the electric energy stored in the power storage device, but the power storage device needs to always secure the electric energy for starting the engine using the motor. There is. For this reason, since the ratio of the electric energy used for motor driving is set to be small by the amount corresponding to the engine start, the motor driving region is reduced by an amount corresponding to the electric energy for the engine starting, and the vehicle fuel consumption is sufficiently improved. I couldn't let you.

  The present invention has been made against the background of the above circumstances, and the object of the present invention is to reduce the electric energy required to start the engine that is always secured by the power storage device as much as possible to reduce the electric motor travel region. An object of the present invention is to provide a control device for a hybrid vehicle that can expand the range.

  In order to achieve such an object, the gist of the present invention is that an electric motor traveling including an engine and an electric motor used as a driving source, and a power storage device that supplies electric energy to the electric motor, and using the electric motor as a driving source. And a hybrid vehicle control device that selectively executes engine running using the engine as a drive source, wherein when the engine is started, fuel is directly injected into the cylinders of the engine and then exploded. It is characterized by increasing the engine speed.

  In this way, when the engine is started, the engine speed is increased by directly injecting and exploding fuel into the cylinders of the engine, so that the electric power for starting the engine using the electric motor can be increased. The need to constantly secure energy in the power storage device is greatly reduced. For this reason, since it is less necessary to set the ratio of the electric energy that can be used for running the motor to be smaller by the electrical energy required for starting the engine, it is necessary to reduce the motor running area by the amount corresponding to the electrical energy for starting the engine. Therefore, the electric motor traveling area can be expanded correspondingly, and the fuel efficiency of the vehicle can be improved accordingly.

  Here, preferably, following the increase in the rotation speed of the engine, the electric motor assists the increase in the rotation speed of the engine. In this way, it is possible to start the engine reliably when the startability of the engine is reduced such that the start-up of the engine rotation speed does not rise smoothly.

  Preferably, when a clutch mechanism is provided between the engine and the electric motor to separate the engine and the electric motor when the electric motor is running, the clutch mechanism is used when starting the engine. And the rotational speed of the engine is increased using only the explosion of the engine. According to this configuration, in the hybrid vehicle including the clutch mechanism, when starting the engine, the electric energy is not used and the fuel is directly injected into the cylinder in the expansion stroke among the plurality of cylinders provided in the engine. Further, since the rotation speed of the engine is raised by explosion, it is not necessary to reduce the motor travel area by an amount corresponding to the electric energy for starting the engine, and the motor travel area can be expanded accordingly. There is an advantage that the control for temporarily increasing the output of the electric motor is not required so as to compensate for the temporary decrease in the driving force accompanying the clutch engagement, which is required when the engine is started using the electric motor during traveling. is there.

  Also preferably, when a clutch mechanism is provided between the engine and the electric motor to separate the engine and the electric motor when the electric motor is running, the engine rotation speed is increased. Then, a start assist is performed for assisting the start-up of the rotational speed of the engine by the electric motor via the clutch mechanism. In this way, in a hybrid vehicle having a clutch mechanism, when the startability of the engine is lowered such that the engine speed does not rise smoothly, the engine can be reliably started. Further, when starting the engine while traveling, the clutch mechanism assists after the engine speed increases, so that torque assist necessary for engine starting can be performed, and the shock of the vehicle due to the deviation of the assist timing by the electric motor can be achieved. Occurrence is preferably prevented.

  Preferably, whether or not to execute the start assist is determined based on at least one of the water temperature of the engine, the stop position of the engine, the exhaust backflow when the engine is stopped, and the fuel pressure of the engine. . That is, when the engine water temperature is low enough to affect the engine start, when the engine stop position is in an angle range where sufficient explosion power cannot be obtained, there is an exhaust backflow when the engine is stopped and sufficient explosion occurs at the start. When it is difficult to expect, when it is determined that the engine startability has deteriorated, such as when the fuel pressure of the engine is high and it is difficult to sufficiently expect fuel injection at the start of the engine, the start assist is executed. In this way, it is possible to start the engine reliably when the startability of the engine is reduced such that the start-up of the engine rotation speed does not rise smoothly.

  Preferably, the rotation speed of the clutch mechanism is synchronized after the engine is started, and the clutch mechanism is engaged after the synchronization is completed. According to this, the occurrence of the engagement shock is prevented when the clutch mechanism is engaged.

  Preferably, at the time of starting the engine, when the accelerator opening is equal to or higher than a predetermined high opening determination value, or when the rate of change of the accelerator opening is equal to or higher than a predetermined rapid operation determination value If the temperature of the catalyst that purifies the exhaust gas of the engine is less than or equal to a preset activation temperature determination value, or if the rotation speed of the motor is less than or equal to a preset start determination value, the start assist is Make it run preferentially. When starting the engine has priority over the fuel consumption of the vehicle, there is an advantage that the engine is started quickly.

It is a figure which shows notionally the structure of the drive system which concerns on the drive device of the hybrid vehicle which is one Example of this invention. It is a two-dimensional coordinate of a vehicle speed axis | shaft and a request | requirement driving force or an accelerator opening degree axis | shaft, Comprising: It is a figure which shows the relationship memorize | stored beforehand by which the electric motor (EV) traveling area and the engine traveling area were set. It is a functional block diagram explaining the principal part of the control function with which the electronic control apparatus of FIG. 1 was equipped. 2 is a flowchart for explaining a main part of engine start control in the electronic control device of FIG. 1.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram conceptually showing the structure of a drive system according to a hybrid vehicle drive apparatus 10 according to an embodiment of the present invention. The driving device 10 shown in FIG. 1 includes an engine 12 and an electric motor MG that function as a driving source, and the driving force generated by the engine 12 and the electric motor MG includes a torque converter 16, an automatic transmission 18, and a difference. It is configured to be transmitted to a pair of left and right drive wheels 24 via a moving gear device 20 and a pair of left and right axles 22, respectively. With this configuration, the driving device 10 is driven using at least one of the engine 12 and the electric motor MG as a driving source for traveling. That is, in the driving device 10, the engine traveling exclusively using the engine 12 as a driving source for traveling, the EV traveling (motor traveling) exclusively using the electric motor MG as a driving source for traveling, and the engine 12 and the electric motor MG are used. One of the hybrid travelings as the driving source for traveling is selectively established.

  The engine 12 is, for example, an internal combustion engine such as a direct injection gasoline engine or a diesel engine in which fuel is directly injected into a combustion chamber. Further, in order to control the drive (output torque) of the engine 12, output control including a throttle actuator that controls opening and closing of an electronic throttle valve, a fuel injection device that performs fuel injection control, an ignition device that performs ignition timing control, and the like. A device 14 is provided. The output control device 14 controls the opening and closing of the electronic throttle valve by the throttle actuator for throttle control in accordance with a command supplied from an electronic control device 58 to be described later, as well as the fuel from the fuel injection device for fuel injection control. The engine 12 is controlled for output by controlling injection and controlling the ignition timing by the ignition device for ignition timing control.

  The electric motor MG is a motor generator having a function as a motor (motor) that generates a driving force and a generator (generator) that generates a reaction force, and there is a power transmission path between the engine 12 and the electric motor MG. A clutch K0 is provided for controlling power transmission in the power transmission path in accordance with the engaged state. That is, the crankshaft 26 that is an output member of the engine 12 is selectively connected to the rotor 30 of the electric motor MG via the clutch K0. The rotor 30 of the electric motor MG is connected to a front cover 32 that is an input member of the torque converter 16.

  The clutch K0 is, for example, a wet multi-plate hydraulic friction engagement device that is controlled by a hydraulic actuator, and its engagement state is engaged (completely engaged) according to the hydraulic pressure supplied from the hydraulic control circuit 34. ), Slip engagement, or release (fully open). When the clutch K0 is engaged, power is transmitted (connected) in the power transmission path between the crankshaft 26 and the front cover 32, while when the clutch K0 is released, the crankshaft 26 is disengaged. Power transmission in the power transmission path between the front cover 32 and the front cover 32 is interrupted. Further, when the clutch K0 is slip-engaged, power transmission according to the transmission torque of the clutch K0 is performed in the power transmission path between the crankshaft 26 and the front cover 32. The clutch K0 is preferably a normally closed clutch that is engaged as the hydraulic pressure command from the electronic control unit 58, which will be described later, becomes lower.

  The automatic transmission 18 is, for example, a stepped automatic transmission mechanism in which any one of a plurality of predetermined gears (speed ratios) is selectively established, and a plurality of gears are selected to select such gears. The engagement element is provided. For example, a plurality of hydraulic friction engagement devices, such as multi-plate clutches and brakes, that are engaged and controlled by a hydraulic actuator, are provided, and the plurality of hydraulic friction engagement devices according to the hydraulic pressure supplied from the hydraulic control circuit 34. By selectively engaging or releasing the combined device, a plurality of (for example, first to sixth speeds) forward shift stages (forward gear stages) according to the combination of the coupling states of the hydraulic friction engagement devices. , Forward travel gear stage) or reverse shift stage (reverse gear stage, reverse travel gear stage) is selectively established.

  The crankshaft 26 is integrally connected to the clutch hub of the clutch K0 at its output end, that is, one end on the electric motor MG side via a drive plate (not shown). Further, a mechanical hydraulic pump 28 is connected to the pump impeller 16p of the torque converter 16, and the hydraulic pressure generated by the mechanical hydraulic pump 28 as the pump impeller 16 rotates is the hydraulic control circuit 34. Is supplied as a source pressure.

  Further, between the pump impeller 16p of the torque converter 16 and the turbine impeller 16t, there is provided a lockup clutch LU that is directly connected so that the pump impeller 16p and the turbine impeller 16t are rotated together. Yes. The lock-up clutch LU is controlled so that its engagement state is engaged (completely engaged), slip-engaged, or released (completely released) according to the hydraulic pressure supplied from the hydraulic control circuit 34. It has become. That is, the lockup clutch LU is provided in a power transmission path between the electric motor MG and the drive wheel 24, and corresponds to a second clutch that controls power transmission in the power transmission path in accordance with the engaged state.

  The electric motor MG includes a rotor 30 that is rotatably supported by the transmission case 36 around the axis of the torque converter 16, and a stator 50 that is integrally fixed to the transmission case 36 on the outer peripheral side of the rotor 30. I have. The rotor 30 is coupled to the front cover 32 via a transmission member that is integrally fixed to the front cover 32 by, for example, welding. The stator 50 includes a core in which a plurality of annular steel plates are laminated in the axial direction and fixed integrally to the transmission case 36, and an annular portion in the circumferential direction of the inner peripheral portion of the core. And a plurality of coils 50b provided continuously in the circumferential direction.

  The electric motor MG configured as described above is connected to a power storage device 57 such as a battery or a capacitor via an inverter 56, and is supplied to the coil 50b by controlling the inverter 56 by an electronic control device 58 described later. The drive current of the motor MG is controlled by adjusting the drive current. In other words, the output torque of the electric motor MG is increased or decreased by controlling the inverter 56 by the electronic control unit 58. The output torque from the electric motor MG is output only to the torque converter 16 when the clutch K0 is disengaged (not engaged), but when the clutch K0 is engaged, a part of the output torque is the torque. It is output to the converter 16 and the other part is output to the engine 12.

In the drive device 10, for example, at the time of transition from EV travel using the electric motor MG as a drive source for travel to engine travel or hybrid travel using the engine 12 as a drive source, the clutch K 0 is engaged to engage the engine 12. Start is performed. That is, when the clutch K0 is engaged slip engagement to complete engagement, the engine 12 is rotationally driven by the torque for starting the engine, which is transmitted via the clutch K0, is thereby the engine rotational speed N _E pulling The engine 12 is started by controlling engine ignition, fuel supply, and the like. Further, at this time, compensation torque is generated by the electric motor MG, and generation of acceleration (deceleration G) in the vehicle longitudinal direction is suppressed. In other words, the engine 12 is started by rotating the engine 12 with the torque obtained from the explosion energy by ignition and the torque obtained from the engagement energy by the clutch K0, that is, the engine starting torque transmitted through the clutch K0. Is done.

  In the control system illustrated in FIG. 1, the electronic control unit 58 includes a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface, and the like, and the CPU uses a temporary storage function of the RAM. While performing signal processing in accordance with a program stored in advance in the ROM, the drive control of the engine 12, the drive control of the electric motor MG, the shift control of the automatic transmission 18, the engagement force control of the clutch K0, and the lockup clutch LU In addition to the basic control such as the engagement control, various controls such as the engine start control of this embodiment described later are executed.

The electronic control device 58 is supplied with various input signals detected by each sensor provided in the driving device 10. For example, a signal representing the accelerator opening A _CC detected by the accelerator opening sensor 60, a signal indicative of the rotational speed (motor rotation speed) N _MG of the motor MG detected by motor rotation speed sensor 62, an engine rotational speed sensor 64 rotational speed (engine rotational speed) N _E or the rotational speed of the crank shaft signal representing the rotational angular phase of 26, the torque converter 16 detected by a turbine rotational speed sensor 66 the turbine wheel 16t of the engine 12 detected by the ( signal representative of the turbine speed) N _T, a signal representing the vehicle speed V detected by the vehicle speed sensor 68, and a signal or the like representing the cooling water temperature T _W of the engine 12 detected by the water temperature sensor 70 to the electronic control unit 58 Entered. Here, the rotational speed N _MG of the motor MG detected by motor rotation speed sensor 62 is an input rotational speed of the torque converter 16, which corresponds to the rotational speed of the pump impeller 16p in the torque converter 16. Further, the rotational speed _NT of the turbine impeller 16 t detected by the turbine rotational speed sensor 66 is an output rotational speed of the torque converter 16 and corresponds to an input rotational speed of the automatic transmission 18.

  Various output signals are output from the electronic control device 58 to each device provided in the driving device 10. For example, a signal supplied to the output control device 14 of the engine 12 for driving control of the engine 12, a signal supplied to the inverter 56 for driving control of the electric motor MG, and shift control of the automatic transmission 18 In addition, a signal supplied to a plurality of electromagnetic control valves in the hydraulic control circuit 34, a signal supplied to the hydraulic control circuit 34 for controlling the engagement of the clutch K0, and the like are supplied from the electronic control unit 58 to each part.

  For example, the electronic control unit 58 stops the engine 12 at a comparatively light load of the vehicle, and uses an electric energy from the power storage device 57 exclusively using the electric motor MG as a driving source for traveling. In the engine running mode in which the engine 12 is a driving source exclusively for driving at a high load, or when temporarily requiring a large driving force such as during rapid acceleration, both the engine 12 and the electric motor MG are used as driving sources for running. A vehicle that has been set in advance, and a regenerative travel mode in which the electric motor MG is used to decelerate or brake by regeneration (power generation) and the regenerated electrical energy is stored in the power storage device 57 when the vehicle decelerates. Select and execute according to the state.

  In the electric motor (EV) travel mode, the drive of the engine 12 is stopped and the clutch K0 is released (completely released). As a result, the power transmission path between the engine 12 and the electric motor MG is interrupted, and no power is transmitted from the engine 12 to the lockup clutch 16 side. Conversely, torque is transmitted from the lockup clutch 16 side to the engine 12. Also not done. On the other hand, in the engine traveling mode or the engine motor traveling mode, the engine 12 is operated and the clutch K0 is completely engaged. As a result, power is transmitted from the engine 12 to the lockup clutch 16 side via the power transmission path between the engine 12 and the electric motor MG, and conversely, torque is transmitted from the lockup clutch 16 side to the engine 12. (Engine braking) is also performed.

  FIG. 2 is a two-dimensional coordinate of the vehicle speed axis indicating the vehicle speed V and the axis indicating the required driving force or the accelerator opening, and shows the relationship in which the electric motor (EV) travel region and the engine travel region are set. Pre-stored in the control device 58. From the relationship shown in FIG. 2, the electronic control unit 58 determines the electric vehicle (EV) traveling region or the engine traveling region based on the actual vehicle speed V and the required driving force or the accelerator opening, and the electric motor (EV) traveling mode or Select the engine running mode. Further, the electronic control unit 58 outputs an engine start command (engine start request) when it is determined to switch from the electric motor (EV) travel region to the engine travel region, for example, as the required driving force or the accelerator opening increases. Then, the engine 12 is started. In addition to this, the engine start command issued when the vehicle is stopped or during running of the electric motor (EV) is associated with the warm-up command of the engine 12, the detection of the decrease in the remaining charge SOC of the power storage device, and the operation of the air conditioner regardless of the travel range. To be issued.

FIG. 3 is a functional block diagram for explaining the main part of the control function provided in the electronic control unit 58 and for starting the engine 12 in response to the engine start command. In FIG. 3, the engine startability determination unit 72 determines that the cooling water temperature T _W (° C.) of the engine 12 detected by the water temperature sensor 70 is equal to or higher than a predetermined determination value Ta, for example. The detected stop angle position (°) of the crankshaft 26 is within a preset easy start angle range that is easy to start in ignition start described later, that is, within an angle range that does not include the vicinity of the top dead center and the vicinity of the bottom dead center. That there is no exhaust backflow into the cylinder caused by the return of the crank angle CA when the engine 12 is stopped, and the pressure of the fuel supplied to the fuel injection valve is a sufficiently high pressure value that allows fuel injection. If everything is satisfied, it is determined that the engine 12 can be easily started. If any of them is not satisfied, it is difficult to start the engine 12. Judge that the situation is difficult.

  The priority start determination unit 74 determines whether or not the engine 12 needs to be started with priority over ignition start, for example, whether the accelerator opening θa (%) is equal to or higher than a predetermined high output manipulated variable determination value. It is determined based on the fact that the change rate dθa / dt of the accelerator opening θa (%) is equal to or higher than a predetermined high acceleration operation determination value. These determinations give priority to quickly starting the engine 12 using the electric motor MG rather than starting the engine 12 without using electric energy when the driver demands high acceleration or high output. Is determined to be necessary. Further, the priority start determination unit 74 determines whether or not the engine 12 needs to be started with priority over the starting startability, that is, the ignition start, for example, if the catalyst temperature (° C.) is equal to or lower than a preset activation determination temperature. Judgment based on. In this determination, it is necessary to avoid the risk that the exhaust gas from the engine 12 that has started ignition is discharged in a deteriorated state by quickly starting the engine 12 using the electric motor MG. To do. Further, the priority start determination unit 74 determines whether or not the engine 12 needs to be started with priority over the starting startability, that is, the ignition start, for example, the rotational speed N of the electric motor MG. _MGDetermination is made based on the fact that (rpm) is lower than a preset rotation speed determination value. This determination is based on the rotational speed N of the engine 12 at which the ignition start has been performed._EMakes a determination that it is necessary to avoid the continuation of the state in which it is difficult to increase the rotation autonomously by quickly starting the engine 12 using the electric motor MG.

  The engine start control unit 76 includes an ignition start control unit 78, a priority start control unit 80, and a rotation synchronization control unit 82. The engine startability determination unit 72 has the ability to start the engine 12 and the priority start determination unit 74 In a normal case where the preferential startability of the engine 12 is denied, the engine 12 is started without consuming electric energy in the electric motor MG only by ignition start in response to the engine start command. However, if the engine startability determination unit 72 denies the startability of the engine 12, or if the priority start determination unit 74 affirms the priority startability of the engine 12, the engine start control unit 76 sets the ignition. In place of or in addition to the start of the engine 12, the engine is ignited and fuel is supplied via the output control device 14, and the cranking of the engine 12 is started to quickly increase the rotation of the engine 12 using the electric motor MG. Thus, the engine 12 is started with priority over the ignition start. The engine start control unit 76 adjusts the rotation speed of the engine 12 by using, for example, the throttle opening degree or the retard timing control of the ignition timing of the output control device 14 so that the clutch K0 is synchronized when the start of the engine 12 is completed. When the synchronization is completed, the clutch K0 is engaged.

  The ignition start control unit 78 detects a cylinder in the expansion stroke among a plurality of cylinders of the engine 12 whose rotation is stopped based on, for example, the crank angle CA, and directly injects fuel into the cylinder and ignites it to explode. Thus, the torque of the engine 12 is increased more than the rotational speed capable of autonomous rotation without using the assist torque of the electric motor MG using electric energy, that is, without consuming electric energy of the power storage device. The engine 12 is started up and the engine 12 is started.

  The priority start control unit 80 performs ignition start when the engine startability determination unit 72 denies the startability of the engine 12 or when the priority start determination unit 74 affirms the priority startability of the engine 12. In place of or in addition to starting the engine 12, the rotational speed of the engine 12 is increased to a speed higher than the rotational speed capable of autonomous rotation using the electric motor MG, and the engine 12 is started quickly.

  The rotation synchronization control unit 82 performs output control so that the clutch K0 is synchronized when the start determination rotation speed set in advance to a value higher than the rotation speed capable of autonomous rotation, for example, about 800 rpm, is reached and the start of the engine 12 is completed. The rotation speed of the engine 12 is adjusted using, for example, throttle opening or ignition timing retardation control of the device 14, and when synchronization is completed, the clutch K0 is engaged.

  FIG. 4 is a flowchart for explaining a main part of the engine start control operation by the electronic control unit 58, which is repeatedly executed at a predetermined cycle.

  First, in step (hereinafter, step is omitted) S1, for example, switching from the electric vehicle (EV) travel region to the engine travel region is determined as the required driving force or the accelerator opening increases, and the engine 12 warm-up command, power storage It is determined whether or not an engine start command (engine start request) has been issued in accordance with detection of a decrease in the remaining charge SOC of the device and the operation of the air conditioner. If the determination at S1 is negative, this routine is terminated.

  If the determination in S1 is affirmative, in S2 and S3 corresponding to the ignition start control unit 78, fuel is directly injected into the cylinder in the expansion stroke among the plurality of cylinders provided in the engine 12 and ignited. The engine 12 is repeatedly exploded to generate torque, and the rotational speed of the engine 12 is increased toward a rotational speed higher than the rotational speed capable of autonomous rotation, and the engine 12 is started. During this time, the assist torque at the start of the electric motor MG using electric energy is not used, and the electric energy of the power storage device is not consumed, and the engine 12 is started only by the ignition start.

Next, in S4 corresponding to the engine startability determination unit 72, for example, the cooling water temperature T _W (° C.) of the engine 12 detected by the water temperature sensor 70 is equal to or higher than a predetermined determination value Ta, an engine rotation speed sensor The stop angle position (°) of the crankshaft 26 detected by 64 is within a preset easy start angle range that is easy to start in the ignition start described later, that is, an angle that does not include the vicinity of the top dead center and the vicinity of the bottom dead center. All within the range, there is no exhaust backflow into the cylinder when the engine 12 is stopped, and the pressure of the fuel supplied to the fuel injection valve is sufficiently high to enable fuel injection. Based on this, the ease of starting the engine 12 is determined.

If the determination in S4 is affirmative, in S5, S6, and S7 corresponding to the priority start determination unit 74, it is determined whether to start the engine 12 in preference to the ignition start. That is, in S5, the accelerator opening degree θa (%) is equal to or higher than a preset high-power operation amount determination value and / or the change rate dθa / dt of the accelerator opening degree θa (%) is preset. Priority startability is determined based on whether or not the acceleration determination value is greater than or equal to the high acceleration operation determination value. If the determination in S5 is negative, priority startability is determined in S6 based on the catalyst temperature (° C.) being equal to or lower than a preset activity determination temperature. If the determination in S6 is negative, the priority startability is determined in S7 based on the fact that the rotational speed N _MG (rpm) of the electric motor MG is lower than a predetermined rotational speed determination value.

If the determination in S4 is affirmative and any of S5 to S7 is negative, ignition start is continued, and in S8 corresponding to the synchronization control unit 82, the engine speed _NE is set in advance. When it is determined that the start completion determination value has been reached and the start of the engine 12 by the ignition start has been completed, for example, the throttle opening or the retard of the ignition timing of the output control device 14 so that the clutch K0 is synchronized. The rotational speed of the engine 12 is adjusted using the control, and when synchronization is completed, the clutch K0 is engaged.

  However, if the determination of S4 is negative or if any of S5 to S7 is affirmative, the motor MG is immediately used in S9 corresponding to the priority start control unit 80. The rotational speed of the engine 12 is increased to a rotational speed higher than the rotational speed, and the engine 12 is started. Thereby, instead of or in addition to starting the engine 12 by ignition start, the rotational speed of the engine 12 is raised to a speed higher than the rotational speed capable of autonomous rotation using the electric motor MG, and the engine 12 is started quickly.

  As described above, according to the electronic control unit 58 of the present embodiment, when the engine 12 is started, the expansion stroke of the plurality of cylinders provided in the engine 12 is not used without using the electrical energy stored in the power storage device 57. Since the rotational speed of the engine 12 is increased by directly injecting and exploding fuel into the cylinder, there is a great need to constantly secure the electric energy for starting the engine 12 using the electric motor MG in the power storage device. Less. For this reason, since it is less necessary to set the ratio of the electric energy that can be used for the electric motor travel to be smaller by the electric energy required for starting the engine 12, the electric motor travel region is set to the engine start amount as indicated by the broken line in FIG. It is not necessary to make it smaller by the amount corresponding to the electric energy, and as shown by the solid line in FIG. 2, the electric motor traveling area can be expanded, and the fuel efficiency of the vehicle can be improved accordingly.

  Further, according to the electronic control unit 58 of the present embodiment, if necessary, the electric motor MG assists the increase in the rotation speed of the engine 12 based on the electric energy if the rotation speed of the engine 12 is increased. Since the start assist is executed, it is possible to start the engine reliably even when the startability of the engine is lowered such that the start-up of the rotational speed of the engine 12 does not rise smoothly.

  In addition, according to the electronic control device 58 of the present embodiment, the clutch K0 (clutch mechanism) is provided that is interposed between the engine 12 and the electric motor MG and separates the engine 12 and the electric motor MG during electric motor travel. When starting the engine 21, the clutch K0 is disconnected, and the rotational speed of the engine 12 is increased using only the explosion of the engine 12. For this reason, when the engine 12 is started, the rotational speed of the engine 12 is increased by directly injecting and exploding fuel into the cylinders in the expansion stroke among the plurality of cylinders provided in the engine 12 without using electric energy. Therefore, it is not necessary to reduce the motor travel area by the amount corresponding to the electric energy for starting the engine, and the motor travel area can be expanded correspondingly, and the engine 12 is started using the motor MG during the motor travel. There is an advantage that the control for temporarily increasing the output of the electric motor MG is not required so as to compensate for the temporary decrease in the driving force accompanying the engagement of the clutch K0 that is required in this case.

  In addition, according to the electronic control difference 58 of the present embodiment, when the clutch K0 that is interposed between the engine 12 and the electric motor MG and separates the engine 12 from the electric motor MG is provided for electric motor travel, the engine 12 Following the increase in the rotation speed, the clutch K0 transmits the torque from the electric motor MG, so that the start assist is performed to assist the increase in the rotation speed of the engine 12. For this reason, in the hybrid vehicle including the clutch K0, when the startability of the engine is lowered such that the start-up of the rotational speed of the engine 12 does not increase smoothly, the engine can be reliably started. Further, when starting the engine while traveling, the clutch K0 assists following the rise of the rotational speed of the engine 12, so that torque assist necessary for engine starting can be performed, and a vehicle shock occurs due to a shift in assist timing by the electric motor MG. It is preferably prevented.

  Further, according to the electronic control unit 58 of the present embodiment, whether or not the start assist is executed depends on the water temperature of the engine 12, the stop position of the engine 12, the exhaust backflow when the engine 12 is stopped, and the fuel pressure of the engine 12. Since it is determined based on at least one, when the startability of the engine 12 is lowered such that the start-up of the rotational speed of the engine 12 does not rise smoothly, the engine can be reliably started.

  Further, according to the electronic control unit 58 of the present embodiment, the rotation speed of the clutch K0 is synchronized after the start of the engine 12 is completed, and the clutch K0 is engaged after the completion of the synchronization. At times, the occurrence of engagement shock is prevented.

  Further, according to the electronic control unit 58 of the present embodiment, when the accelerator opening is equal to or higher than a preset high opening determination value when the engine 12 is started, the rate of change of the accelerator opening is set in advance. When it is equal to or higher than the rapid operation determination value, when the temperature of the catalyst for purifying the exhaust gas of the engine is equal to or lower than a preset activation temperature determination value, or the rotation speed of the electric motor is equal to or lower than a predetermined start determination value In this case, since the start assist is preferentially executed, there is an advantage that the engine 12 is started quickly when the start of the engine 12 is prioritized over the fuel consumption of the vehicle.

  The preferred embodiments of the present invention have been described in detail with reference to the drawings. However, the present invention is not limited to these embodiments, and may be implemented in other modes.

  For example, in the above-described embodiment, the hybrid vehicle in which the clutch K0 is provided in the power transmission path between the engine 12 and the motor generator MG has been described. However, the engine is the first rotation of the planetary gear type power distribution device. It may be a so-called two-motor hybrid vehicle that is connected to the elements, the first electric motor is connected to the second rotating element of the power distribution device, and the second electric motor is connected to the third rotating element of the power distribution device. . In this two-motor hybrid vehicle, for example, the ignition start of the engine is performed with the first electric motor in the idle state, and the start assist is performed by the first electric motor.

  In the above-described embodiment, the clutch K0 provided in the power transmission path between the engine 12 and the motor generator MG is a hydraulic friction engagement device whose engagement state is controlled by hydraulic pressure. For example, an electromagnetic clutch or a magnetic powder clutch whose electromagnetic state is controlled electromagnetically may be provided in a power transmission path between the engine 12 and the motor generator MG. That is, the present invention can be widely applied to hybrid vehicles provided with a clutch for controlling power transmission in the power transmission path in the power transmission path between the engine and the motor generator.

  In the above-described embodiment, the example in which the present invention is applied to the hybrid vehicle 10 including the stepped automatic transmission 18 including a plurality of hydraulic friction engagement devices has been described. 18 may not necessarily be provided. Further, instead of the automatic transmission 18, the present invention is also suitably applied to a hybrid vehicle including a CVT such as a belt-type continuously variable transmission or a toroidal-type continuously variable transmission as an automatic transmission. Further, the present invention may be applied to a hybrid vehicle in which the plurality of electric motors function as an electric continuously variable transmission by electric paths between the plurality of electric motors.

  In the above-described embodiment, when assisting the rising of the rotational speed of the engine 12 using the electric motor MG when starting the engine 12, not only the lock-up clutch LU is released, but also the frictional force in the automatic transmission 18. The combined device may be released to release the power transmission path therein.

  In addition, although not illustrated one by one, the present invention is implemented with various modifications within a range not departing from the gist thereof.

10: drive device, 12: engine, 14: output control device, 57: power storage device, 58: electronic control device, 72: engine startability determination unit, 74: priority start determination unit, 76: engine start control unit, 78: Ignition start control unit, 80: priority start control unit, 82: rotation synchronization control unit, K0: clutch (clutch mechanism), MG: electric motor

[0002]
This is realized by consuming electric energy, but it is necessary to always secure electric energy for starting the engine by using an electric motor in the power storage device. For this reason, since the ratio of the electric energy used for motor driving is set to be small by the amount corresponding to the engine start, the motor driving region is reduced by an amount corresponding to the electric energy for the engine starting, and the vehicle fuel consumption is sufficiently improved. I couldn't let you.
[0006]
The present invention has been made against the background of the above circumstances, and the object of the present invention is to reduce the electric energy required to start the engine that is always secured by the power storage device as much as possible to reduce the electric motor travel region. An object of the present invention is to provide a control device for a hybrid vehicle that can expand the range.
Means for Solving the Problems [0007]
In order to achieve such an object, the gist of the present invention is that an electric motor traveling including an engine and an electric motor used as a driving source, and a power storage device that supplies electric energy to the electric motor, and using the electric motor as a driving source. And a hybrid vehicle control device that selectively executes engine running using the engine as a drive source, wherein when the engine is started, fuel is directly injected into the cylinders of the engine and then exploded. A control device for a hybrid vehicle that raises the rotational speed of an engine and assists the raising of the rotational speed of the engine by the electric motor following the raising of the rotational speed of the engine, and is provided between the engine and the electric motor. And a clutch mechanism for separating between the engine and the electric motor in the electric motor traveling, After the start of the engine, a start assist is performed by the electric motor for assisting the start of the rotation of the engine through the clutch mechanism, and after the start of the engine is completed, the rotation speed of the clutch mechanism is And the clutch mechanism after completion of the synchronization is engaged.
Effect of the Invention [0008]
In this way, when the engine is started, the engine speed is increased by directly injecting and exploding fuel into the cylinders of the engine, so that the electric power for starting the engine using the electric motor can be increased. The need to constantly secure energy in the power storage device is greatly reduced. For this reason, since it is less necessary to set the ratio of the electric energy that can be used for running the motor to be smaller by the electrical energy required for starting the engine, it is necessary to reduce the motor running area by the amount corresponding to the electrical energy for starting the engine. Therefore, the electric motor traveling area can be expanded correspondingly, and the fuel efficiency of the vehicle can be improved accordingly. Furthermore, when the startability of the engine is lowered such that the start-up of the engine speed does not rise smoothly, the engine can be reliably started. Furthermore, in a hybrid vehicle having a clutch mechanism, when the startability of the engine is lowered such that the engine speed does not rise smoothly, the engine can be reliably started. Further, when starting the engine while traveling, the clutch mechanism assists after the engine speed increases, so that torque assist necessary for engine starting can be performed, and the shock of the vehicle due to the deviation of the assist timing by the electric motor can be achieved. Occurrence is preferably prevented. Furthermore, the occurrence of engagement shock is prevented when the clutch mechanism is engaged.

[0003]
[0009]
[0010]
Here, preferably, when a clutch mechanism is provided between the engine and the electric motor to separate the engine and the electric motor when the electric motor is running, the clutch is used when starting the engine. The rotation speed of the engine is increased using only the engine explosion by separating the mechanism. According to this configuration, in the hybrid vehicle including the clutch mechanism, when starting the engine, the electric energy is not used and the fuel is directly injected into the cylinder in the expansion stroke among the plurality of cylinders provided in the engine. Further, since the rotation speed of the engine is raised by explosion, it is not necessary to reduce the motor travel area by an amount corresponding to the electric energy for starting the engine, and the motor travel area can be expanded accordingly. There is an advantage that the control for temporarily increasing the output of the electric motor is not required so as to compensate for the temporary decrease in the driving force accompanying the clutch engagement, which is required when the engine is started using the electric motor during traveling. is there.
[0011]

[0004]
[0012]
Preferably, whether or not to execute the start assist is determined based on at least one of the water temperature of the engine, the stop position of the engine, the exhaust backflow when the engine is stopped, and the fuel pressure of the engine. . That is, when the engine water temperature is low enough to affect the engine start, when the engine stop position is in an angle range where sufficient explosion power cannot be obtained, there is an exhaust backflow when the engine is stopped and sufficient explosion occurs at the start. When it is difficult to expect, when it is determined that the engine startability has deteriorated, such as when the fuel pressure of the engine is high and it is difficult to sufficiently expect fuel injection at the start of the engine, the start assist is executed. In this way, it is possible to start the engine reliably when the startability of the engine is reduced such that the start-up of the engine rotation speed does not rise smoothly.
[0013]
[0014]
Preferably, at the time of starting the engine, when the accelerator opening is equal to or higher than a predetermined high opening determination value, or when the rate of change of the accelerator opening is equal to or higher than a predetermined rapid operation determination value If the temperature of the catalyst for purifying the exhaust gas of the engine is equal to or lower than a preset activation temperature determination value, or the rotation speed of the motor is equal to or lower than a predetermined start determination value, the start assist is prioritized. Make it run. When starting the engine has priority over the fuel consumption of the vehicle, there is an advantage that the engine is started quickly.
BRIEF DESCRIPTION OF THE DRAWINGS [0015]
FIG. 1 is a diagram conceptually showing the structure of a drive system according to a drive device for a hybrid vehicle that is an embodiment of the present invention.
FIG. 2 is a diagram showing a two-dimensional coordinate of a vehicle speed axis and a required driving force or an accelerator opening axis, and showing a previously stored relationship in which an electric motor (EV) traveling area and an engine traveling area are set.
FIG. 3 is a functional block diagram for explaining the main part of the control function provided in the electronic control unit of FIG.

[0011]
This is issued when the remaining charge SOC is detected and the air conditioner is activated.
[0033]
FIG. 3 is a functional block diagram for explaining the main part of the control function provided in the electronic control unit 58 and for starting the engine 12 in response to the engine start command. In FIG. 3, the engine startability determination unit 72 determines that the cooling water temperature T _W (° C.) of the engine 12 detected by the water temperature sensor 70 is equal to or higher than a predetermined determination value Ta, for example. The detected stop angle position (°) of the crankshaft 26 is within a preset easy start angle range that is easy to start in ignition start described later, that is, within an angle range that does not include the vicinity of the top dead center and the vicinity of the bottom dead center. That there is no exhaust backflow into the cylinder caused by the return of the crank angle CA when the engine 12 is stopped, and the pressure of the fuel supplied to the fuel injection valve is a sufficiently high pressure value that allows fuel injection. If everything is satisfied, it is determined that it is easy to start the engine 12, and if either is not satisfied, the engine 12 is started. Is determined to be difficult.
[0034]
For example, the accelerator opening θa (%) is equal to or higher than a predetermined high opening degree determination value. This is determined based on the fact that the change rate dθa / dt of the accelerator opening θa (%) is equal to or greater than a preset rapid operation determination value. These determinations give priority to quickly starting the engine 12 using the electric motor MG rather than starting the engine 12 without using electric energy when the driver demands high acceleration or high output. Is determined to be necessary. Further, the priority start determination unit 74 determines whether or not the engine 12 needs to be started with priority over the priority startability, that is, the ignition start, for example, if the catalyst temperature (° C.) is equal to or lower than a preset activation temperature determination value. Determine based on. In this determination, it is necessary to avoid the risk that the exhaust gas from the engine 12 that has started ignition is discharged in a deteriorated state by quickly starting the engine 12 using the electric motor MG. To do. The priority start determination unit 74 also starts the engine 12 with priority.

[0012]
For example, the presence or absence of the necessity of starting with priority over the ignition start is determined based on, for example, that the rotational speed N _MG (rpm) of the electric motor MG is lower than a preset start determination value. This determination avoids that the rotational speed N _ε of the engine 12 that has started ignition continues to be in a state where it is difficult to autonomously increase the rotation by quickly starting the engine 12 using the electric motor MG. Makes the necessary determination.
[0035]
The engine start control unit 76 includes an ignition start control unit 78, a priority start control unit 80, and a rotation synchronization control unit 82. The engine startability determination unit 72 has the ability to start the engine 12 and the priority start determination unit 74 In a normal case where the preferential startability of the engine 12 is denied, the engine 12 is started without consuming electric energy in the electric motor MG only by ignition start in response to the engine start command. However, if the engine startability determination unit 72 denies the startability of the engine 12, or if the priority start determination unit 74 affirms the priority startability of the engine 12, the engine start control unit 76 sets the ignition. In place of or in addition to the start of the engine 12, the engine is ignited and fuel is supplied via the output control device 14, and the cranking of the engine 12 is started to quickly increase the rotation of the engine 12 using the electric motor MG. Thus, the engine 12 is started with priority over the ignition start. The engine start control unit 76 adjusts the rotation speed of the engine 12 by using, for example, the throttle opening degree or the retard timing control of the ignition timing of the output control device 14 so that the clutch K0 is synchronized when the start of the engine 12 is completed. When the synchronization is completed, the clutch K0 is engaged.
[0036]
The ignition start control unit 78 detects a cylinder in the expansion stroke among a plurality of cylinders of the engine 12 whose rotation is stopped based on, for example, the crank angle CA, and directly injects fuel into the cylinder and ignites it to explode. Thus, the torque of the engine 12 is increased more than the rotational speed capable of autonomous rotation without using the assist torque of the electric motor MG using electric energy, that is, without consuming electric energy of the power storage device. Start up and start engine 12

[0014]
The cooling water temperature T _W (° C.) of the engine 12 detected by the water temperature sensor 70 is equal to or higher than a preset determination value Ta, and the stop angle position (°) of the crankshaft 26 detected by the engine rotation speed sensor 64 is set. It is within a preset easy start angle range that is easy to start in the ignition start described later, that is, within an angle range that does not include the vicinity of the top dead center and the vicinity of the bottom dead center. The ease of starting the engine 12 is determined based on the fact that there is no exhaust backflow and that the pressure of the fuel supplied to the fuel injection valve is a sufficiently high pressure value that allows fuel injection. The
[0043]
If the determination in S4 is affirmative, in S5, S6, and S7 corresponding to the priority start determination unit 74, it is determined whether to start the engine 12 in preference to the ignition start. That is, in S5, the accelerator opening degree θa (%) is equal to or higher than a preset high opening degree determination value and / or the acceleration rate θa (%) change rate dθa / dt is set in advance. Preferential startability is determined based on whether or not it is greater than or equal to the operation determination value. If the determination in S5 is negative, priority startability is determined in S6 based on the catalyst temperature (° C.) being equal to or lower than a preset activation temperature determination value. If the determination in S6 is negative, the priority startability is determined in S7 based on the fact that the rotational speed N _MG (rpm) of the electric motor MG is lower than a preset start determination value.
[0044]
If the determination in S4 is affirmative and any of S5 to S7 is negative, ignition start is continued, and in S8 corresponding to the synchronization control unit 82, the engine speed _NE is set in advance. When it is determined that the start completion determination value has been reached and the start of the engine 12 by the ignition start has been completed, for example, the throttle opening or the retard of the ignition timing of the output control device 14 so that the clutch K0 is synchronized. The rotational speed of the engine 12 is adjusted using the control, and when synchronization is completed, the clutch K0 is engaged.
[0045]
However, if the determination of S4 is negative or if any of S5 to S7 is affirmative, the motor MG is immediately used in S9 corresponding to the priority start control unit 80. More than the rotation speed that can be rotated

[0017]
When the accelerator opening is equal to or higher than a preset high opening determination value, the catalyst for purifying the exhaust gas of the engine when the change rate of the accelerator opening is equal to or more than a preset rapid operation determination value When the temperature of the motor is equal to or lower than a preset activation temperature determination value, or when the rotation speed of the electric motor is equal to or lower than a predetermined start determination value, the start assist is preferentially executed. In the case where the engine 12 is prioritized over the starting, there is an advantage that the engine 12 is started quickly.
[0053]
The preferred embodiments of the present invention have been described in detail with reference to the drawings. However, the present invention is not limited to these embodiments, and may be implemented in other modes.
[0054]
For example, in the above-described embodiment, the hybrid vehicle in which the clutch K0 is provided in the power transmission path between the engine 12 and the motor generator MG has been described. However, the engine is the first rotation of the planetary gear type power distribution device. It may be a so-called two-motor hybrid vehicle that is connected to the elements, the first electric motor is connected to the second rotating element of the power distribution device, and the second electric motor is connected to the third rotating element of the power distribution device. . In this two-motor hybrid vehicle, for example, the ignition start of the engine is performed with the first electric motor in the idle state, and the start assist is performed by the first electric motor.
[0055]
In the above-described embodiment, the clutch K0 provided in the power transmission path between the engine 12 and the motor generator MG is a hydraulic friction engagement device whose engagement state is controlled by hydraulic pressure. For example, an electromagnetic clutch or a magnetic powder clutch whose electromagnetic state is controlled electromagnetically may be provided in a power transmission path between the engine 12 and the motor generator MG. That is, the present invention can be widely applied to hybrid vehicles provided with a clutch for controlling power transmission in the power transmission path in the power transmission path between the engine and the motor generator.
[0056]
In the above-described embodiment, the example in which the present invention is applied to the hybrid vehicle 10 including the stepped automatic transmission 18 including a plurality of hydraulic friction engagement devices has been described. 18 may not necessarily be provided. Also,

Claims (7)

A hybrid comprising an engine and an electric motor used as a driving source, and a power storage device for supplying electric energy to the electric motor, wherein the electric motor traveling using the electric motor as a driving source and the engine traveling using the engine as a driving source are selectively performed. A control device for a vehicle,
A control apparatus for a hybrid vehicle, wherein when the engine is started, the rotational speed of the engine is increased by directly injecting and exploding fuel into a cylinder of the engine.   2. The control apparatus for a hybrid vehicle according to claim 1, wherein, following the increase in the rotation speed of the engine, the electric motor assists the increase in the rotation speed of the engine. A clutch mechanism that is provided between the engine and the electric motor and disconnects between the engine and the electric motor in the electric motor traveling;
2. The control apparatus for a hybrid vehicle according to claim 1, wherein at the time of starting the engine, the clutch mechanism is disconnected and only the engine explosion is used to increase the rotational speed of the engine. A clutch mechanism that is provided between the engine and the electric motor and disconnects between the engine and the electric motor in the electric motor traveling;
3. The control of a hybrid vehicle according to claim 2, wherein a start assist for assisting an increase in the rotation speed of the engine is executed by the electric motor via the clutch mechanism following the increase in the rotation speed of the engine. apparatus.   Whether or not to execute the start assist is determined based on at least one of a water temperature of the engine, a stop position of the engine, an exhaust reverse flow when the engine is stopped, and a fuel pressure of the engine. Item 5. The control device for a hybrid vehicle according to item 2 or 4.   The hybrid vehicle control device according to claim 2 or 4, wherein after the start of the engine is completed, a rotation speed of the clutch mechanism is synchronized, and the clutch mechanism after the synchronization is completed is engaged. When starting the engine, if the accelerator opening is greater than or equal to a predetermined high opening determination value, or if the change rate of the accelerator opening is greater than or equal to a predetermined rapid operation determination value, the exhaust of the engine When the temperature of the catalyst for purifying gas is equal to or lower than a preset activation temperature determination value, or when the rotation speed of the electric motor is equal to or lower than a predetermined start determination value, the start assist is preferentially executed. The control apparatus for a hybrid vehicle according to claim 2 or 4, characterized in that:

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