JP2019043347A - Hybrid vehicle - Google Patents

Abstract

To provide a hybrid vehicle that suppresses a shock and improves fuel economy when shifting an engine from a stoichiometric operation zone or lean operation zone to a stop operation zone.SOLUTION: A hybrid vehicle is provided with operation zone switchover means that is capable of switching an engine among a stop operation zone, a lean operation zone in which an air-fuel ratio falls in a lean, and a stoichiometric operation zone in which an air-fuel ratio falls nearby a stoichiometric. Further, in a case where the operation zone switchover means determines the engine operation zone to be switched from the stoichiometric operation zone or lean operation zone to the stop operation zone in response to required drive force, a drive force control part inhibits the engine from switching over from the stoichiometric operation zone or lean operation zone to the stop operation zone via the stoichiometric operation zone, to switch directly to the stop operation zone and cause a driving motor to generate positive or negative drive force for a given period of time.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a hybrid vehicle capable of traveling with an engine and an electric motor as power sources.

  Patent Document 1 discloses a technology for generating electric power in order to assist a torque by a driving motor or to increase an engine load in order to suppress a shock at the time of transition from an lean operation region to a stoichiometric operation region. It is disclosed.

JP, 2008-068802, A

Although it is possible to suppress shock when transitioning from the high torque stoichiometric operation region or lean operation region of the engine to the stop operation region, rich spike fuel is used because it passes through the low torque stoichiometric operation region when transitioning to the stop operation region. There is a problem that fuel consumption is deteriorated.
An object of the present invention is to provide a hybrid vehicle that improves the fuel efficiency while suppressing a shock when shifting from a high torque stoichiometric operation region or a lean operation region of an engine to a stop operation region.

In order to achieve the above object, in the hybrid vehicle of the present invention, an engine, a drive motor, and a drive force of the engine are transmitted to a drive wheel, and a drive force of the drive motor is transmitted to the drive wheel A hybrid vehicle comprising: a force transmitting means; and a driving force control unit for controlling a driving force ratio of the engine and a driving force ratio of the driving motor by the driving force transmitting means according to a traveling state.
An operation area switching means capable of switching between a stop operation area of the engine, a lean operation area in which the air fuel ratio is lean, and a stoichiometric operation area in which the air fuel ratio is close to the stoichiometry is provided. When it is determined that the operation range of the engine is switched from the stoichiometric operation range or the lean operation range to the stop operation range of the engine, the driving force control unit determines that the engine is in the stoichiometric operation range or the lean operation range. To prohibit the switching to the stop driving range via the driving range and directly switch to the stop driving range, and to eliminate the torque step at the time of switching, the driving force of the drive motor for a predetermined time for a predetermined time It was decided to generate

  Therefore, it is possible to suppress the shock when shifting from the engine stoichiometric operation region or lean operation region to the engine stop operation region, and to improve fuel efficiency.

FIG. 1 is an overall system diagram showing a rear wheel drive hybrid vehicle of a first embodiment. FIG. 6 is a control block diagram showing an arithmetic processing program in the integrated controller of the first embodiment. It is a figure which shows an example of the driver request torque map used for driver request torque calculation in the driver request torque calculating part of FIG. It is a figure which shows the normal mode map used for selection of a target mode in the mode selection part of FIG. It is a figure which shows an example of the target charging / discharging amount map used for the calculation of target charging / discharging electric power in the target charging / discharging calculating part of FIG. FIG. 5 is a characteristic view of an operating range of an engine to which the first embodiment is applied. FIG. 7 is a flowchart showing a process for controlling the driving force of the engine and the driving motor at the time of switching from the lean operation area to the stop operation area according to the first embodiment. It is a time chart showing drive power control processing of an engine and a drive motor at the time of change from a lean operation field to a stop operation field in case battery SOC of Example 1 is more than predetermined value. It is a time chart showing drive power control processing of an engine and a drive motor at the time of change from a lean operation field to a stop operation field in case battery SOC of Example 1 is less than a predetermined value. FIG. 13 is a flowchart showing a process of controlling the driving force of the engine and the driving motor at the time of switching from the stoichiometric operation region to the stop operation region according to the second embodiment. It is a time chart showing driving force control processing of an engine and a drive motor at the time of switching from a stoichiometry operation field to a stop operation field when battery SOC of Example 2 is more than predetermined value. It is a time chart showing drive power control processing of an engine and a drive motor at the time of switching from a stoichiometry operation field to a stop operation field when battery SOC of Example 2 is less than a predetermined value.

Example 1
FIG. 1 is an entire system diagram showing a rear wheel drive hybrid vehicle according to a first embodiment. The drive system of the hybrid vehicle in the first embodiment includes an engine E, which is an internal combustion engine, a first clutch CL1, a motor generator MG that functions as a drive motor, a second clutch CL2, and an automatic function that functions as a driving force transmission unit. It has a transmission AT, a propeller shaft PS, a differential DF, a left drive shaft DSL, a right drive shaft DSR, a left rear wheel RL (drive wheel), and a right rear wheel RR (drive wheel). Here, FL is the left front wheel, and FR is the right front wheel.

The engine E is a gasoline engine, and a valve opening degree of a throttle valve (not shown) and the like is controlled based on a control command from an engine controller 1 described later. A flywheel FW is provided on the engine output shaft. Further, the engine E has a motor SSG. The motor SSG is connected to the crankshaft of the engine E using a belt, functions as a starter motor for starting the engine, and operates as an alternator that generates electric power as required.
The first clutch CL1 is a dry clutch interposed between the engine E and the motor generator MG as a drive motor, and can always be engaged by an urging force of a diaphragm spring or the like. On the basis of the control command, the control hydraulic pressure generated by the first clutch hydraulic unit 6 includes slip engagement for performing torque transmission while slipping, and engagement / release is controlled.

Motor generator MG is a synchronous motor generator in which permanent magnets are embedded in a rotor and a stator coil is wound around a stator, and three-phase AC generated by inverter 3 is generated based on a control command from motor controller 2 described later. It controls by applying. The motor generator MG can also operate as a motor driven to rotate by receiving supply of power from the battery 4 (hereinafter, this state is referred to as “powering”), or when the rotor is rotated by an external force. Can also function as a generator that generates an electromotive force at both ends of the stator coil to charge the battery 4 (hereinafter, this operation state is referred to as “regeneration”). The rotor of motor generator MG is connected to the input shaft of automatic transmission AT via a damper (not shown).
The second clutch CL2 is a clutch interposed between the motor generator MG and the left and right rear wheels RL and RR, and is generated by the AT hydraulic control unit 8 based on a control command from the AT controller 7 described later. The control oil pressure includes slip engagement that transmits torque while slipping, and engagement and release are controlled.

  The automatic transmission AT is a transmission that automatically switches a stepped gear ratio such as the seventh forward speed and the reverse first speed according to the vehicle speed VSP, the accelerator opening degree (the driver's accelerator pedal operation) APO, and the like. The second clutch CL2 is not newly added as a dedicated clutch, but diverts some friction engagement elements among a plurality of friction engagement elements engaged at each shift position of the automatic transmission AT. The output shaft of the automatic transmission AT is connected to the left and right rear wheels RL and RR via a propeller shaft PS as a vehicle drive shaft, a differential DF, a left drive shaft DSL, and a right drive shaft DSR. As the second clutch CL2, for example, a multi-plate clutch capable of continuously controlling the oil flow rate and the hydraulic pressure by a proportional solenoid is used.

  This hybrid drive system has three traveling modes in accordance with the engagement / release state of the first clutch CL1. The first travel mode is an electric vehicle travel mode (hereinafter abbreviated as “EV travel mode”) as a motor use travel mode in which only the power of the motor generator MG travels as a power source when the first clutch CL1 is open. It is. The second travel mode is an engine use travel mode (hereinafter abbreviated as “HEV travel mode”) in which the vehicle travels while including the engine E as a power source in the engaged state of the first clutch CL1. The third travel mode is abbreviated as “WSC travel mode” in which the second clutch CL2 is slip-controlled in the engaged state of the first clutch CL1 and travels while including the engine E as a power source. ). This mode is a mode in which creep travel can be achieved particularly when the battery SOC is low or the engine water temperature is low.

  The "HEV drive mode" has three drive modes: "engine drive mode", "motor assist drive mode", and "running power generation mode". In the "engine travel mode", drive wheels are moved using only the engine E as a power source. In the “motor assist travel mode”, drive wheels are moved using two of an engine E and a motor generator MG as a power source. The “traveling power generation mode” causes the motor generator MG to function as a generator while moving the drive wheels RR and RL with the engine E as a power source. At the time of constant speed operation and acceleration operation, the power of engine E is used to operate motor generator MG as a generator. Further, at the time of the deceleration operation, the braking energy is regenerated and generated by the motor generator MG and used for charging the battery 4. In addition, when the vehicle is stopped, a power generation mode in which motor generator MG is operated as a generator using the power of engine E is provided.

  Next, a control system of the hybrid vehicle will be described. As shown in FIG. 1, the control system of the hybrid vehicle in the first embodiment includes an engine controller 1, a motor controller 2, an inverter 3, a battery 4, a first clutch controller 5, and a first clutch hydraulic unit 6 , The AT hydraulic control unit 8, the brake controller 9, the integrated controller 10, and the SSG controller SSGCU. The engine controller 1, the motor controller 2, the first clutch controller 5, the AT controller 7, the brake controller 9, the integrated controller 10, and the SSG controller SSGCU share a CAN communication line 11 capable of exchanging information with each other. Connected through.

Based on the target engine torque command from the integrated controller 10 based on the required driving force, the engine controller 1 performs stoichiometric operation in an FC (fuel cut) operation region which is a stop operation region and a lean combustion operation region in which the air fuel ratio becomes lean. An operation area switching means 1a is provided to switch to a stoichiometric combustion operation area that is adjacent to the engine.
Further, the engine controller 1 inputs the engine identification number from the cylinder identification sensor 32 and the engine rotational speed information from the engine rotational speed sensor 12 and responds to a target engine torque command from the integrated controller 10, etc. A command for controlling the engine rotational speed (Te: engine torque) is output, for example, to a throttle actuator that controls the throttle opening of a throttle valve (not shown). Information such as the accelerator opening APO, the engine rotational speed Ne, the current operation area, the switching target operation area, the discrimination cylinder, etc. is supplied to the integrated controller 10 via the CAN communication line 11.
The SSG controller SSGCU outputs a command to operate the motor SSG as a starter motor function and an alternator function based on a command signal from the integrated controller 10.

  The motor controller 2 inputs information from the resolver 13 for detecting the rotor rotational position of the motor generator MG, and responds to a target motor torque command or the like from the integrated controller 10 to control the motor operating point of the motor generator MG as an inverter. Output to 3 The motor controller 2 monitors the battery SOC representing the charge state of the battery 4. The monitored battery SOC information is used for control information of the motor generator MG, and is also supplied to the integrated controller 10 via the CAN communication line 11.

  The first clutch controller 5 receives sensor information from the first clutch hydraulic pressure sensor 14 and the first clutch stroke sensor 15 and a first clutch control command from the integrated controller 10, and transmits the first clutch hydraulic pressure to the first clutch hydraulic unit 6. Output the CL1 engagement / disengagement control command. Information on the first clutch stroke C1S is supplied to the integrated controller 10 via the CAN communication line 11.

  The AT controller 7 includes various sensor signals of the accelerator switch 28 for outputting a range signal corresponding to the operation position of the accelerator opening sensor 16, the vehicle speed sensor 17, the second clutch hydraulic pressure sensor 18, and the select lever 27. The control command is input, and the control command is output to the AT hydraulic control unit 8. The accelerator opening APO, the vehicle speed VSP, and the inhibitor switch signal are supplied to the integrated controller 10 via the CAN communication line 11. Also, the inhibitor switch signal is sent to the in-meter indicator 29 provided in the combination meter (not shown), and the current range position is displayed.

  The brake controller 9 inputs sensor information from the wheel speed sensor 19 and the brake stroke sensor 20 which detect the wheel speeds of the four wheels. Then, at the time of brake depression braking, mechanical braking force (braking force by friction brake) compensates for the insufficient amount of regenerative braking force to the required braking force determined from the brake stroke BS based on the regenerative coordination control command from the integrated controller 10. Perform regenerative coordination brake control.

  The integrated controller 10 manages the energy consumption of the entire vehicle and is a controller for running the vehicle with the highest efficiency, and detects the motor rotation number sensor 21 for detecting the motor rotation number Nm and the second clutch output rotation number N2out Second clutch output rotational speed sensor 22, a second clutch torque sensor 23 for detecting a second clutch transmission torque capacity TCL2, a brake hydraulic pressure sensor 24, a temperature sensor 25 for detecting a temperature of the second clutch CL2, and back and forth Information obtained through the G sensor 26 for detecting acceleration, the first clutch temperature sensor 30, the inverter temperature sensor 31, and the CAN communication line 11 is input.

  In addition, integrated controller 10 controls the operation of engine E by a control command to engine controller 1, controls the operation of motor generator MG as a drive motor by a control command to motor controller 2, and controls first clutch controller 5. Control of engagement / disengagement control of the first clutch CL1 by control instruction, engagement / disengagement control of the second clutch CL2 by control instruction to the AT controller 7, and starter motor function or alternator function by control instruction to the SSG controller SSGCU And motor control.

  FIG. 2 is a control block diagram showing a control configuration in the integrated controller 10 of the first embodiment. The integrated controller 10 executes various operations in a control cycle of 10 msec, for example. The integrated controller 10 includes a driver request torque calculation unit 100, a mode selection unit 200, a target charge / discharge calculation unit 300, an operating point commanding unit 400 including a driving force control unit 10a, and a transmission control unit 500.

  The driver request torque calculation unit 100 calculates a driver request torque Tdd, which is a request driving force, from the accelerator opening APO and the vehicle speed VSP using the driver request torque map shown in FIG.

  Next, the mode map will be described. FIG. 4 is a normal mode map of the first embodiment. The normal mode map includes an EV travel mode, a WSC travel mode, and an HEV travel mode, and calculates a target mode from the accelerator opening APO and the vehicle speed VSP. This mode map outputs, as a target mode, a mode corresponding to the position of the operating point determined by the accelerator opening APO and the vehicle speed VSP. However, even if the EV drive mode is selected, if the battery SOC is equal to or less than a predetermined value or there is another request for prohibition of idling stop, the HEV drive mode is forcibly set to the target mode.

  In the normal mode map of FIG. 4, the WSC → EV switching line and the HEV → EV switching line are set to the predetermined opening APO2 when viewed from the accelerator opening APO axis. The HEV → EV switching line is set to a predetermined vehicle speed VSP2 when viewed from the vehicle speed VSP axis. The HEV-> WSC switching line is a vehicle speed region where the rotational speed is smaller than the lower limit vehicle speed VSP1 that matches the idle rotational speed of the engine E when the automatic transmission AT is in the first gear in the area less than the predetermined accelerator opening APO1. It is set to. Further, in the area above the predetermined accelerator opening APO1, a large driving force is required, so the WSC travel mode is set up to the vehicle speed VSP1 'area higher than the lower limit vehicle speed VSP1. When the battery SOC is low and the EV drive mode can not be achieved, the WSC drive mode is set to be selected even when the vehicle is started.

  When the accelerator opening APO is large, it may be difficult to achieve the requirement with the engine torque Te and the motor generator torque Tmg corresponding to the engine rotational speed near the idle rotational speed. Here, more engine torque Te can be output as the engine speed Ne increases. From this, the engine speed Ne is increased to output a larger torque. Therefore, even if the WSC drive mode is executed to a vehicle speed higher than the lower limit vehicle speed VSP1, the transition from the WSC drive mode to the HEV drive mode can be made in a short time. This case is a WSC region expanded to the lower limit vehicle speed VSP1 'shown in FIG.

Target charge / discharge operation unit 300 calculates the target charge / discharge power from battery SOC using the target charge / discharge amount map shown in FIG. 5.
In operating point commanding section 400, driving provided by operating point commanding section 400 as an operating point attainment target from the accelerator opening APO, driver request torque Tdd, target mode, vehicle speed VSP, and target charge / discharge power. The force control unit 10a controls the drive power ratio of the engine E and the drive power ratio of the motor generator MG, which is a drive motor, to control the transient target engine torque and the target motor. The generator torque, the target second clutch transmission torque capacity, and the target gear position of the automatic transmission AT and the first clutch solenoid current command are calculated and commanded.
Further, the driving force control unit 10 a controls the driving force ratio of the engine E and the driving force ratio of the motor generator MG as a driving motor, and also uses information obtained from the engine controller 1 via the CAN communication line 11. When the operation area information to be switched is the stop operation area, a transition command to the stop operation area is directly output to the operation mode switching means 1a of the engine control 1, and the motor generator MG as a drive motor And calculates and outputs a target motor generator torque to the motor generator MG so as to absorb the torque step.

In addition, operating point command unit 400 has an engine start control unit that starts engine E when transitioning from the EV travel mode to the HEV travel mode. The engine start control unit sets the second clutch CL2 to the second clutch transmission torque capacity corresponding to the driver request torque Tdd, and brings about a slip control state. Further, the motor generator MG is subjected to rotation speed control, and the target motor generator rotation speed is set to a value obtained by adding a predetermined slip amount to the drive wheel rotation speed equivalent value. In this state, the engine start control unit outputs a command to function as a starter motor to the SSG controller SSGCU, and releases the first clutch CL1. As a result, engine cranking in which the heat generation of the first clutch CL1 is suppressed is performed. Then, after cranking by the motor SSG, an engagement command is output to the first clutch CL1. This starts the engine.
The shift control unit 500 drives and controls the solenoid valve in the automatic transmission AT so as to achieve the target second clutch transmission torque capacity and the target shift speed according to the shift schedule shown in the shift map. In the shift map, the target shift speed is set in advance based on the vehicle speed VSP and the accelerator opening APO.

  FIG. 6 is an operating region characteristic diagram of the engine applied to the first embodiment.

The vertical axis represents engine torque, which is the engine driving force, and the horizontal axis represents engine rotation. The region surrounded by the broken line where the engine torque on the vertical axis is negative is the FC (fuel cut) operation region which is the stop operation region of the engine E, and the region where the engine torque is positive is surrounded by the dashed dotted line. A low torque stoichiometric operation region with a relatively small torque, a high torque stoichiometric operation region with a large torque surrounded by a broken line, and a lean operation region surrounded by a solid line in the central portion are shown.
That is, in response to the engine torque which is a required driving force for the engine E, there are an FC operation area, a low torque stoichiometric operation area, and a high torque stoichiometric operation area.

  FIG. 7 is a flowchart showing drive power control processing of the engine and the drive motor at the time of switching from the lean operation region to the stop operation region according to the first embodiment.

In step S1, it is determined whether or not the accelerator opening APO is near 0 deg. When the accelerator opening APO is near 0 deg, the process proceeds to step S2, and when the accelerator opening APO is not near 0 deg, the process returns to step S1.
In step S2, timer counting is started.
In step S3, the operation area switching means 1a of the engine controller 1 determines the switching from the current lean operation area to the FC operation area which is the stop area.
In step S4, it is determined whether or not the battery SOC is equal to or greater than a predetermined threshold value (SOC_a). If the battery SOC is equal to or higher than the threshold (SOC_a), the process proceeds to step S5. If the battery SOC is not equal to or higher than the threshold (SOC_a), the process proceeds to step S8.

In step S5, the driving force control unit 10a included in the operating point commanding unit 400 instructs direct switching of the engine E to the FC operation range and positive driving (driving torque) of the motor generator MG as a driving motor.
In step S6, it is determined whether the timer time after the accelerator opening degree is near 0 is equal to or greater than a threshold (t0) as a predetermined time. If the timer time is equal to or more than the threshold (t0), the process proceeds to step S7. If the timer time is not equal to or more than the threshold (t0), the process returns to step S6.
In step S7, the driving force control unit 10a included in the operating point commanding unit 400 instructs the engine E to maintain the FC operating area and stop the motor generator MG, which is a driving motor.

In step S8, the driving force control unit 10a included in the operating point commanding unit 400 instructs switching of the engine E to the lower limit torque in the lean operation range and negative drive (power generation) of the motor generator MG as a drive motor.
In step S9, it is determined whether the timer time after the accelerator opening degree is near 0 is equal to or greater than the threshold (t0). If the timer time is equal to or more than the threshold (t0), the process proceeds to step S10. If the timer time is not equal to or more than the threshold (t0), the process returns to step S9.
In step S10, the driving force control unit 10a included in the operating point commanding unit 400 instructs the engine E to be directly switched to the FC operation range and to stop the motor generator MG, which is a driving motor.
This flowchart is repeated, and the driving force control processing of the engine and the driving motor at the time of switching from the lean operation region to the stop operation region is performed.

  FIG. 8 is a time chart showing a driving force control process of the engine and the driving motor at the time of switching from the lean operation region to the stop operation region when the battery SOC of the first embodiment is a predetermined value or more.

The horizontal axis is time.
From the top, changes in the vehicle speed VSP, the accelerator opening APO corresponding to the driver's accelerator pedal operation, the engine torque in the operating region of the engine E, and the torque of the motor generator MG as a drive motor are shown.
The vehicle speed VSP is constant until time t1, and is reduced due to deceleration in a coasting state after time t1.
The accelerator opening APO is a predetermined opening until time t1, but the driver releases the accelerator pedal at time t1, and the accelerator opening APO is closed.
In addition, engine E is in a drive (drive) state in the lean operation region until time t1, the driver releases the accelerator pedal at time t1, accelerator opening APO is closed, and battery SOC is equal to or higher than the threshold (SOC_a) Therefore, it shifts to the FC operation area which is the stop operation area.
The torque of the motor generator MG, which is a driving motor, generates a torque step for the engine E to shift from the lean operation region to the FC operation region at time t1. And decreases toward time t2 due to the two-step slope, and stops at time t2.
Thereby, the shock by switching to the FC operation range is suppressed.
The time between time t1 and t2 corresponds to the threshold (t0) as the predetermined time.

  FIG. 9 is a time chart showing the driving force control process of the engine and the driving motor at the time of switching from the lean operation region to the stop operation region when the battery SOC of the first embodiment is less than a predetermined value.

The horizontal axis is time.
From the top, changes in the vehicle speed VSP, the accelerator opening APO corresponding to the driver's accelerator pedal operation, the engine torque in the operating region of the engine E, and the torque of the motor generator MG as a drive motor are shown.
The vehicle speed VSP is constant until time ta, and is reduced due to deceleration in a coast state after time ta.
Until time ta, the accelerator opening APO is a predetermined opening, but at time ta the driver releases the accelerator pedal and the accelerator opening APO is closed.
In addition, engine E is in the drive (drive) state in the lean operation region until time tb, and the driver releases the accelerator pedal at time ta, and the accelerator opening APO is closed, but the threshold value (the battery SOC is a predetermined value) Because it is less than SOC_a), it shifts to the lower limit torque of the lean operation area at time tb slightly delayed from time ta, and stops directly without passing through the low torque stoichiometric operation area at time tc after the threshold (t0) It shifts to the FC operation area which is the operation area.
The torque of the motor generator MG, which is a driving motor, is shifted to the lower limit torque of the lean operation range at time tb, and thereafter is shifted to the FC operation range at time tc, so that a torque step occurs. In order to absorb the torque step, a negative driving force (power generation) is generated at time tb, and decreases toward time tc after the threshold (t0) elapses, and stops at time tc.
Thereby, the shock by switching to the FC operation range is suppressed.
The time from time ta to time tc corresponds to the threshold t0 as the predetermined time.

As described above, in the first embodiment, the following effects can be obtained.
(1) Driving force transmission for transmitting the driving force of the engine E, the motor generator MG as a driving motor, and the driving force of the engine E to the driving wheels RR, RL and transmitting the driving force of the motor generator MG to the driving wheels RR, RL In a hybrid vehicle comprising an automatic transmission AT functioning as a means, and a driving force control unit 10a controlling the driving force ratio of the engine E and the driving force ratio of the motor generator MG by the automatic transmission AT according to traveling conditions. ,
An operation area switching means capable of switching between an FC operation area which is a stop operation area of the engine E, a lean operation area in which the air fuel ratio is lean and an stoichiometric operation area in which the air fuel ratio becomes stoichiometric is provided. When it is determined that the operating range of the engine E is switched from the lean operating range to the FC operating range of the engine E according to the driving force, the driving force control unit 10a passes the stoichiometric operating range from the lean operating range of the engine E To prohibit the switching to the FC operating region and directly generate the positive or negative driving force in the motor generator MG for a predetermined time so as to directly switch to the FC operating region and eliminate the torque step during switching. And
Therefore, the engine does not shift to the stoichiometric operation region, and the rich spike fuel becomes unnecessary, and the fuel efficiency can be improved, and the shock of switching to the FC operation region having the stop operation region is suppressed, and the drivability is improved. be able to.

(2) When the SOC of the battery is equal to or higher than the threshold value (SOC_a) which is a predetermined value, the motor generator MG is positively driven to switch directly to the stop operation region and eliminate the torque step at the time of switching. generate.
Therefore, the shock of the operation area switching can be suppressed, the energy management of the battery 4 can be optimized, the consumption of the charge state of the battery 4 can be suppressed, and the fuel consumption can be improved.

(3) When the SOC of the battery is less than the threshold value (SOC_a) which is a predetermined value, transition to the lower limit torque of the lean operation region is made between time tb and time tc, and transition to the FC operation region is made at time tc. To make the motor generator MG generate negative driving force so as to eliminate the torque step when switching, at time tc after the threshold value (t0) has elapsed, directly stop operation area without passing through the low torque stoichiometric operation area Transition to the FC operating range.
Therefore, the shock of the operation area switching can be suppressed, the energy management of the battery 4 can be optimized, the consumption of the charge state of the battery 4 can be suppressed, and the fuel consumption can be improved.

  FIG. 10 is a flowchart showing a process of controlling the driving force of the engine and the driving motor at the time of switching from the high torque stoichiometric operation region to the stop operation region according to the second embodiment.

In step S11, it is determined whether or not the accelerator opening APO is near 0 deg. When the accelerator opening APO is near 0 deg, the process proceeds to step S12, and when the accelerator opening APO is not near 0 deg, the process returns to step S11.
In step S12, timer counting is started.
In step S13, the operation area switching means 1a of the engine controller 1 determines the switching from the current high torque stoichiometric operation area to the FC operation area which is the stop area.
In step S14, it is determined whether the battery SOC is equal to or higher than a threshold (SOC_a) which is a predetermined value. If the battery SOC is equal to or higher than the predetermined threshold value (SOC_a), the process proceeds to step S15. If the battery SOC is not equal to or higher than the predetermined threshold value (SOC_a), the process proceeds to step S18.

In step S15, the driving force control unit 10a included in the operating point commanding unit 400 instructs direct switching of the engine E to the FC operation range and positive driving (driving torque) of the motor generator MG as a driving motor.
In step S16, it is determined whether the timer time after the accelerator opening degree is near 0 is equal to or greater than a predetermined threshold value (t0). If the timer time is equal to or more than the threshold (t0), the process proceeds to step S17. If the timer time is not equal to or more than the threshold (t0), the process returns to step S16.
In step S17, the driving force control unit 10a included in the operating point commanding unit 400 instructs the engine E to maintain the FC operating area and stop the motor generator MG, which is a driving motor.

In step S18, the driving force control unit 10a included in the operating point commanding unit 400 instructs switching of the engine E to the lower limit torque in the lean operation range and negative drive (power generation) of the motor generator MG as a drive motor.
In step S19, it is determined whether or not the timer time after the accelerator opening degree is near 0 is equal to or greater than a predetermined threshold value (t0). If the timer time is equal to or more than the threshold (t0), the process proceeds to step S10. If the timer time is not equal to or more than the threshold (t0), the process returns to step S9.
In step S20, the driving force control unit 10a included in the operating point commanding unit 400 instructs the engine E to be directly switched to the FC operation range and to stop the motor generator MG, which is a driving motor.
This flowchart is repeated, and the driving force control processing of the engine and the driving motor at the time of switching from the lean operation region to the stop operation region is performed.

  FIG. 11 is a time chart showing the driving force control process of the engine and the driving motor at the time of switching from the high torque stoichiometric operation region to the stop operation region when the battery SOC of the second embodiment is a predetermined value or more.

The horizontal axis is time.
From the top, changes in the vehicle speed VSP, the accelerator opening APO corresponding to the driver's accelerator pedal operation, the engine torque in the operating region of the engine E, and the torque of the motor generator MG as a drive motor are shown.
The vehicle speed VSP is constant until time t1, and is reduced due to deceleration in a coasting state after time t1.
The accelerator opening APO is a predetermined opening until time t1, but the driver releases the accelerator pedal at time t1, and the accelerator opening APO is closed.
Further, the engine E is in a driving (driving) state in the high torque stoichiometric operation region until time t1, and the driver releases the accelerator pedal at time t1, and the accelerator opening APO is closed. Shift to the driving range.
The torque of the motor generator MG, which is a driving motor, generates a torque step for shifting the engine E from the high torque stoichiometric operation region to the FC operation region at time t1. The driving force is generated, and due to the two-step inclination, it decreases toward time t2 and stops at time t2.
Thereby, the shock by switching to the FC operation range is suppressed.
The time between time t1 and t2 corresponds to the threshold (t0) as the predetermined time.

  FIG. 12 is a time chart showing a driving force control process of the engine and the driving motor at the time of switching from the high torque stoichiometric operation region to the stop operation region when the battery SOC of the second embodiment is less than a predetermined value.

The horizontal axis is time.
From the top, changes in the vehicle speed VSP, the accelerator opening APO corresponding to the driver's accelerator pedal operation, the engine torque in the operating region of the engine E, and the torque of the motor generator MG as a drive motor are shown.
The vehicle speed VSP is constant until time ta, and is reduced due to deceleration in a coast state after time ta.
Until time ta, the accelerator opening APO is a predetermined opening, but at time ta the driver releases the accelerator pedal and the accelerator opening APO is closed.
In addition, engine E is in the drive (drive) state in the high torque stoichiometric operation region until time tb, and the driver releases the accelerator pedal at time ta and accelerator opening APO is closed, but battery SOC is at a predetermined value. Because it is less than a certain threshold (SOC_a), it shifts to the lower limit torque of the lean operation range at time tb slightly delayed from time ta, and shifts to the FC operation range which is the stop operation range at time tc after the threshold (t0) elapses Do.
The torque of the motor generator MG, which is a driving motor, is shifted to the lower limit torque of the lean operation range at time tb, and thereafter, to the FC operation range at time tc, a torque step occurs. In order to absorb this torque step, a negative driving force (power generation) is generated, it decreases toward time tc, and stops at time tc after the threshold (t0) elapses.
Thereby, the shock by switching to the FC operation range is suppressed.
The time from time ta to time tc corresponds to the threshold (t0) as the predetermined time.

As described above, in the second embodiment, the following effects can be obtained.
(1) Driving force transmission for transmitting the driving force of the engine E, the motor generator MG as a driving motor, and the driving force of the engine E to the driving wheels RR, RL and transmitting the driving force of the motor generator MG to the driving wheels RR, RL In a hybrid vehicle comprising an automatic transmission AT functioning as a means, and a driving force control unit 10a controlling the driving force ratio of the engine E and the driving force ratio of the motor generator MG by the automatic transmission AT according to traveling conditions. ,
An operation area switching means capable of switching between a stop operation area of the engine E, a lean operation area in which the air fuel ratio becomes lean, and a stoichiometric operation area in which the air fuel ratio approaches the stoichiometry is provided. When it is determined that the operating range of the engine E is switched from the high torque stoichiometric operating range to the stop operating range of the engine E, the driving force control unit 10a determines that the engine E has high torque from the stoichiometric operating range to low torque. The motor generator MG is positively or negatively driven for a predetermined time so as to prohibit switching to the stop operation region via the stoichiometric operation region, directly switch to the stop operation region, and eliminate the torque step during switching. It was decided to generate power.
Therefore, the engine does not shift to the stoichiometric operation region, and the rich spike fuel becomes unnecessary, and the fuel efficiency can be improved, and the shock of switching to the FC operation region having the stop operation region is suppressed, and the drivability is improved. be able to.

(2) When the SOC of the battery is equal to or higher than the threshold value (SOC_a) which is a predetermined value, the motor generator MG is positively driven to switch directly to the stop operation region and eliminate the torque step at the time of switching. generate.
Therefore, the shock of the operation area switching can be suppressed, the energy management of the battery 4 can be optimized, the consumption of the charge state of the battery 4 can be suppressed, and the fuel consumption can be improved.

(3) When the SOC of the battery is less than the threshold value (SOC_a) which is a predetermined value, transition to the lower limit torque of the lean operation region is made between time tb and time tc, and transition to the FC operation region is made at time tc. To make the motor generator MG generate negative driving force so as to eliminate the torque step when switching, at time tc after the threshold value (t0) has elapsed, directly stop operation area without passing through the low torque stoichiometric operation area Transition to the FC operating range.
Therefore, the shock of the operation area switching can be suppressed, the energy management of the battery 4 can be optimized, the consumption of the charge state of the battery 4 can be suppressed, and the fuel consumption can be improved.

Other Embodiments
As mentioned above, although this invention was demonstrated based on the Example, another structure may be sufficient as a specific structure. For example, although the FR type hybrid vehicle has been described in the embodiment, it may be an FF type hybrid vehicle.

1 Engine controller
1a Operation area switching means
2 Motor controller
10 Integrated controller
10a Driving force control unit
AT Automatic transmission (driving force transmission means)
CL1 first clutch
CL2 second clutch
E engine
MG motor generator (drive motor)
RR, RL drive wheel

Claims (6)

An engine, a drive motor, and drive power transmission means for transmitting the drive power of the engine to the drive wheels and transmitting the drive power of the drive motor to the drive wheels;
A driving force control unit that controls the driving force ratio of the engine and the driving force ratio of the driving motor by the driving force transmission means according to the traveling state;
In a hybrid vehicle comprising
The engine is provided with operation area switching means capable of switching between a stop operation area of the engine, a lean operation area in which the air fuel ratio is lean, and a stoichiometric operation area in which the air fuel ratio is close to the stoichiometry.
When it is determined that the operating range switching means switches the operating range of the engine from the stoichiometric operating range or the lean operating range to the stop operating range of the engine according to the required driving force,
The driving force control unit prohibits switching of the engine from the stoichiometric operation region or the lean operation region to the stop operation region via the stoichiometric operation region, and directly switches to the stop operation region.
Generating a positive or negative driving force to the driving motor for a predetermined time so as to eliminate a torque step at the time of switching;
A hybrid vehicle characterized by In the hybrid vehicle according to claim 1,
When the drive range switching means determines switching of the drive range of the engine to the stop drive range corresponding to the required driving force in the lean drive range, the drive range switching means directly switches to the stop drive range. And the drive power output control means causes the drive motor to generate positive drive power for a predetermined time.
A hybrid vehicle characterized by In the hybrid vehicle according to claim 1,
When the operating area switching means determines switching of the operating area of the engine to the stop operating area corresponding to the required driving force in the lean operating area, the operating area switching means temporarily performs the lean operating. While maintaining the lower limit torque of the range, the drive force output control means causes the drive motor to generate a negative drive force, and after a predetermined time has elapsed, directly switches to the stop operation range, and the negative by the drive motor Stop the driving force of
A hybrid vehicle characterized by In the hybrid vehicle according to claim 1,
The operating area switching means directly stops when the operating area switching means determines switching of the operating area of the engine to the stop operating area according to the required driving force in the high torque stoichiometric operating area. The drive power output control means causes the drive motor to generate a positive drive power for a predetermined time while switching to the drive area.
A hybrid vehicle characterized by In the hybrid vehicle according to claim 1,
When the operating area switching means determines switching of the operating area of the engine to the stop operating area in response to the required driving force during the high torque stoichiometric operating area, the operating area switching means temporarily The lower limit torque of the lean operation range is maintained, and the drive force output control means causes the drive motor to generate a negative drive force, and after a predetermined time has elapsed, directly switches to the stop operation range and Stop the negative driving force by the motor,
A hybrid vehicle characterized by In the hybrid vehicle according to any one of claims 1 to 5,
When the SOC of the battery is equal to or more than a predetermined value, a positive driving force is generated in the driving motor, and when the SOC of the battery is less than the predetermined value, a negative driving force is generated in the driving motor.
A hybrid vehicle characterized by

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