JP2016175544A - Control device for hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for a hybrid vehicle, the device being designed to improve start response and fuel cost, by carrying out engine start through combustion assist start control.SOLUTION: A drive system with a first clutch 3 interposed between a horizontal engine 2 and a motor generator 4 is provided. This FF hybrid vehicle is provided with a hybrid control module 81 designed such that when an engine start is requested, the motor generator 4 is used as a starter motor, and the first clutch 3 is fastening controlled to start the horizontal engine 2. The hybrid control module 81 exerts combustion assist start control for cranking, such that, when the engine is started, combustion start torque caused by injection and ignition of fuel into a piston in an expansion stroke among stationary engine pistons is added to a motor torque based on the fastening capacity of the first clutch 3.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control device for a hybrid vehicle that performs engine start control using a starter motor as a drive source motor when an engine start request is issued.

  Conventionally, when there is an engine start request, the motor is used as a starter motor, the second clutch is brought into a slip engagement state, and the first clutch is engaged and cranked. An engine start control device for a hybrid vehicle that starts an engine by performing fuel injection and ignition when the engine speed increases to a predetermined speed is known (for example, see Patent Document 1).

JP 2007-69817 A

  However, in the conventional apparatus, the starter motor is used as the driving source motor, and the engine start control is performed by covering all of the engine cranking torque with the motor torque. For this reason, there has been a problem that an increase in the engine speed is left to the motor torque (= CL1 engagement capacity), and the start response in which the front and rear G rises is delayed. Further, it is necessary to start the engine at a timing when there is a motor torque margin used for starting the engine, and accordingly, there is a problem that a region for selecting the EV mode is narrowed and fuel consumption is reduced.

  The present invention has been made paying attention to the above problems, and an object of the present invention is to provide a control device for a hybrid vehicle that improves start response and fuel efficiency by performing engine start by combustion assist start control. .

In order to achieve the above object, the present invention includes a drive system in which an engine and a motor are used as drive sources and a first clutch is interposed between the engine and the motor.
In this hybrid vehicle, when there is an engine start request, a controller is provided that starts the engine by controlling the engagement of the first clutch by using the motor as a starter motor.
A combustion assist start control for cranking the engine by adding a fuel start torque generated by fuel injection and ignition to a piston in an expansion stroke among the stopped engine pistons at the time of starting the engine. I do.

Therefore, at the time of engine start, combustion assist start control is performed in which cranking is performed by adding fuel start torque generated by fuel injection and ignition to the piston in the expansion stroke of the stopped engine pistons to the motor torque due to the engagement capacity of the first clutch. Done.
That is, when the engine is started, the increase in the engine speed is accelerated by the combustion start torque in the engine, so that the rotation synchronization timing between the motor and the engine is advanced and the rise of the front and rear G is accelerated (improvement of the start response).
The engine start request is issued when the motor torque in the EV mode becomes a torque obtained by subtracting the motor torque used for starting the engine from the maximum motor torque. On the other hand, the motor torque (= engagement capacity of the first clutch) used for starting the engine can be reduced by the combustion starting torque from the engine. For this reason, the selection area in the EV mode by stopping the engine is expanded (improvement of fuel consumption).
Thus, by performing engine start by combustion assist start control, it is possible to improve the start response and improve the fuel consumption.

1 is an overall system diagram illustrating an FF hybrid vehicle to which a control device according to a first embodiment is applied. 6 is a flowchart showing a flow of combustion assist start control processing executed in the hybrid control module of the first embodiment. It is explanatory drawing which shows the feasibility study including the dispersion | variation at the time of setting the torque generation estimated time T0, the injection timer T1, and the ignition timer T2 in the combustion assist start control process of Example 1. FIG. 6 is a time chart showing characteristics of a CL1 hydraulic pressure command, a CL1 torque, an ENG torque, a fuel cut step (FCSTP), and a CL2 differential rotation when combustion assist start control is performed at the time of start (CL2 slip at the start of start). CL1 oil pressure command, CL1 torque, ENG torque, fuel cut step (FCSTP), CL2 differential rotation, motor when combustion assist start control is performed at start-up from R / L (CL2 LU & motor torque positive at start) It is a time chart which shows each characteristic of torque. CL1 oil pressure command, CL1 torque, ENG torque, fuel cut step (FCSTP), CL2 differential rotation, motor torque when combustion assist start control is performed when starting from the coast (CL2 LU & motor torque negative at start) It is a time chart which shows each characteristic. It is a time chart which shows the acceleration characteristic and rotation speed characteristic for demonstrating the start response improvement effect. It is a relationship characteristic figure which shows the relationship between the motor rotation speed of a motor generator and a motor torque for demonstrating a fuel consumption improvement effect.

  Hereinafter, the best mode for realizing a control device for a hybrid vehicle of the present invention will be described based on a first embodiment shown in the drawings.

First, the configuration will be described.
The control device in the first embodiment is applied to an FF hybrid vehicle (an example of a hybrid vehicle) in which left and right front wheels are drive wheels and a belt type continuously variable transmission is mounted as a transmission. Hereinafter, the configuration of the control device for the FF hybrid vehicle according to the first embodiment will be described by dividing it into an “overall system configuration” and a “combustion assist start control processing configuration”.

[Overall system configuration]
FIG. 1 shows an overall system of an FF hybrid vehicle to which the control device of the first embodiment is applied. Hereinafter, the overall system configuration of the FF hybrid vehicle will be described with reference to FIG.

  As shown in FIG. 1, the drive system of the FF hybrid vehicle includes a horizontally placed engine 2, a first clutch 3 (abbreviated “CL1”), a motor generator 4 (abbreviated “MG”), and a second clutch 5 (abbreviated). "CL2") and a belt type continuously variable transmission 6 (abbreviated as "CVT"). The output shaft of the belt type continuously variable transmission 6 is drivingly connected to the left and right front wheels 10R and 10L via a final reduction gear train 7, a differential gear 8, and left and right drive shafts 9R and 9L. The left and right rear wheels 11R and 11L are driven wheels.

  The horizontal engine 2 is an engine disposed in a front room with a starter motor 1 and a crankshaft direction as a vehicle width direction, an electric water pump 12, and a crankshaft rotation sensor 13 for detecting reverse rotation of the horizontal engine 2. Have. This horizontal engine 2 has an “MG start mode” in which cranking is performed by the motor generator 4 while the first clutch 3 is slidingly engaged, and a starter motor 1 which is powered by the 12V battery 22 as an engine starting method. Starter start mode ". The “starter start mode” is selected only when a limited condition such as a cryogenic temperature condition is satisfied.

  The motor generator 4 is a three-phase AC permanent magnet synchronous motor connected to the transverse engine 2 via the first clutch 3. The motor generator 4 uses a high-power battery 21 described later as a power source, and an inverter 26 that converts direct current to three-phase alternating current during power running and converts three-phase alternating current to direct current during regeneration is connected to the stator coil via an AC harness 27. Connected. The first clutch 3 interposed between the horizontal engine 2 and the motor generator 4 is a dry or wet multi-plate clutch operated by hydraulic operation, and complete engagement / slip engagement / release is controlled by the first clutch hydraulic pressure. Is done.

  The second clutch 5 is a hydraulically operated wet multi-plate friction clutch interposed between the motor generator 4 and the left and right front wheels 10R and 10L as drive wheels, and is fully engaged / slip engaged by the second clutch hydraulic pressure. / Open is controlled. The second clutch 5 in the first embodiment uses a forward clutch 5a and a reverse brake 5b provided in a forward / reverse switching mechanism using a planetary gear. That is, the forward clutch 5 a is the second clutch 5 during forward travel, and the reverse brake 5 b is the second clutch 5 during reverse travel.

  The belt-type continuously variable transmission 6 includes a primary pulley 6a, a secondary pulley 6b, and a belt 6c that spans the pulleys 6a and 6b. And it is a transmission which obtains a stepless gear ratio by changing the winding diameter of belt 6c with the primary pressure and secondary pressure supplied to a primary oil chamber and a secondary oil chamber. The belt type continuously variable transmission 6 includes a main oil pump 14 (mechanical drive) that is rotated by a motor shaft (= transmission input shaft) of a motor generator 4 as a hydraulic pressure source, and a sub oil pump used as an auxiliary pump. 15 (motor drive). And the control which produces the primary pressure and the secondary pressure of the 1st clutch pressure, the 2nd clutch pressure, and the belt-type continuously variable transmission 6 from the line pressure PL produced | generated by adjusting the pump discharge pressure from a hydraulic power source as a source pressure. A valve unit 6d is provided.

  The first clutch 3, the motor generator 4 and the second clutch 5 constitute a hybrid drive system called a one-motor / two-clutch. The main drive modes are "EV mode", "HEV mode", "WSC mode" Have The “EV mode” is an electric vehicle mode in which the first clutch 3 is disengaged and the second clutch 5 is engaged and only the motor generator 4 is used as a drive source, and traveling in the “EV mode” is referred to as “EV traveling”. The “HEV mode” is a hybrid vehicle mode in which both the clutches 3 and 5 are engaged and the transverse engine 2 and the motor generator 4 are used as driving sources, and traveling in the “HEV mode” is referred to as “HEV traveling”. The “WSC mode” is a CL2 slip engagement mode in which the motor generator 4 is controlled by the motor rotation speed and the second clutch 5 is engaged with the engagement torque capacity corresponding to the target drive torque in the “HEV mode” or the “EV mode”. is there.

  As shown in FIG. 1, the braking system of the FF hybrid vehicle includes a brake operation unit 16, a brake fluid pressure control unit 17, left and right front wheel brake units 18R and 18L, and left and right rear wheel brake units 19R and 19L. ing. In this braking system, when regeneration is performed by the motor generator 4 during brake operation, regenerative cooperative control is performed in which the hydraulic braking force shares the amount obtained by subtracting the regenerative braking force from the requested braking force with respect to the requested braking force based on the pedal operation. Done.

  The brake operation unit 16 includes a brake pedal 16a, a negative pressure booster 16b that uses the intake negative pressure of the horizontal engine 2, a master cylinder 16c, and the like. The regenerative cooperative brake unit 16 generates a predetermined master cylinder pressure in accordance with the brake depression force applied from the driver to the brake pedal 16a, and is a unit having a simple configuration that does not use an electric booster.

  Although not shown, the brake fluid pressure control unit 17 includes an electric oil pump, a pressure increasing solenoid valve, a pressure reducing solenoid valve, an oil path switching valve, and the like. Control of the brake fluid pressure control unit 17 by the brake control unit 85 exhibits a function of generating wheel cylinder fluid pressure when the brake is not operated and a function of adjusting wheel cylinder fluid pressure when the brake is operated. Control using the hydraulic pressure generation function when the brake is not operated includes traction control (TCS control), vehicle behavior control (VDC control), emergency brake control (automatic brake control), and the like. Controls using the hydraulic pressure adjustment function during brake operation include regenerative cooperative brake control, antilock brake control (ABS control), and the like.

  The left and right front wheel brake units 18R and 18L are provided on the left and right front wheels 10R and 10L, respectively, and the left and right rear wheel brake units 19R and 19L are provided on the left and right rear wheels 11R and 11L, respectively. Give. These brake units 18R, 18L, 19R and 19L have wheel cylinders (not shown) to which the brake fluid pressure generated by the brake fluid pressure control unit 17 is supplied.

  As shown in FIG. 1, the power supply system of the FF hybrid vehicle includes a high-power battery 21 as a power supply for the motor generator 4 and a 12V battery 22 as a power supply for a 12V system load.

  The high-power battery 21 is a secondary battery mounted as a power source for the motor generator 4. For example, a lithium ion battery in which a cell module constituted by a large number of cells is set in a battery pack case is used. The high-power battery 21 has a built-in junction box in which relay circuits for supplying / cutting off / distributing high-power are integrated, and further includes a cooling fan unit 24 having a battery cooling function, a battery charging capacity (battery SOC) and a battery. And a lithium battery controller 86 for monitoring the temperature.

  The high-power battery 21 and the motor generator 4 are connected via a DC harness 25, an inverter 26, and an AC harness 27. The inverter 26 is provided with a motor controller 83 that performs power running / regenerative control. That is, the inverter 26 converts the direct current from the DC harness 25 into the three-phase alternating current to the AC harness 27 during power running that drives the motor generator 4 by discharging the high-power battery 21. Further, the three-phase alternating current from the AC harness 27 is converted into direct current to the DC harness 25 during regeneration in which the high-power battery 21 is charged by power generation by the motor generator 4.

  The 12V battery 22 is a secondary battery mounted as a power source for a starter motor 1 and a 12V system load that is an auxiliary machine. For example, a lead battery mounted in an engine vehicle or the like is used. The high voltage battery 21 and the 12V battery 22 are connected via a DC branch harness 25a, a DC / DC converter 37, and a battery harness 38. The DC / DC converter 37 converts a voltage of several hundred volts from the high-power battery 21 into 12V, and the charge amount of the 12V battery 22 is controlled by controlling the DC / DC converter 37 by the hybrid control module 81. The configuration is to be managed.

  As shown in FIG. 1, the electronic control system of the FF hybrid vehicle includes a hybrid control module 81 (abbreviation: “HCM”) as an electronic control unit having an integrated control function for appropriately managing energy consumption of the entire vehicle. Yes. Other electronic control units include an engine control module 82 (abbreviation: “ECM”), a motor controller 83 (abbreviation: “MC”), and a CVT control unit 84 (abbreviation: “CVTCU”). Furthermore, it has a brake control unit 85 (abbreviation: “BCU”) and a lithium battery controller 86 (abbreviation: “LBC”). These electronic control units 81, 82, 83, 84, 85, 86 are connected via a CAN communication line 90 (CAN is an abbreviation for “Controller Area Network”) so that bidirectional information can be exchanged, and share information with each other.

  The hybrid control module 81 performs various integrated controls based on input information from other electronic control units 82, 83, 84, 85, 86, an ignition switch 91, and the like.

  The engine control module 82 performs start control, fuel injection control, ignition control, fuel cut control, engine idle rotation control, etc. for the horizontally placed engine 2 based on input information from the hybrid control module 81, the crank angle sensor 92, and the like. Do.

  The motor controller 83 performs power running control, regenerative control, motor creep control, motor idle control, etc. of the motor generator 4 according to control commands for the inverter 26 based on input information from the hybrid control module 81, the motor rotational speed sensor 93, and the like. Do.

  The CVT control unit 84 outputs a control command to the control valve unit 6d based on input information from the hybrid control module 81, the accelerator opening sensor 94, the vehicle speed sensor 95, the inhibitor switch 96, the ATF oil temperature sensor 97, and the like. The CVT control unit 84 performs the engagement hydraulic pressure control of the first clutch 3, the engagement hydraulic pressure control of the second clutch 5, the transmission hydraulic pressure control by the primary pressure and the secondary pressure of the belt type continuously variable transmission 6, and the like.

  The brake control unit 85 outputs a control command to the brake hydraulic pressure control unit 17 based on input information from the hybrid control module 81, the brake switch 98, the brake stroke sensor 99, and the like. The brake control unit 85 performs TCS control, VDC control, automatic brake control, regenerative cooperative brake control, ABS control, and the like.

  The lithium battery controller 86 manages the battery SOC, battery temperature, and the like of the high-power battery 21 based on input information from the battery voltage sensor 100, the battery temperature sensor 101, and the like.

[Combustion assist start control processing configuration]
FIG. 2 shows the flow of the combustion assist start control process executed by the hybrid control module 81 (controller) of the first embodiment. Hereinafter, each step of FIG. 2 representing a combustion assist start control processing configuration in which the control is started based on the engine start request in the “EV mode” and the control is ended by the independent operation of the horizontally installed engine 2 will be described.

In step S1, a CL1 hydraulic pressure command for hydraulically engaging the first clutch CL1 released in the “EV mode” is output, and the process proceeds to step S2.
Here, the “CL1 oil pressure command” is a precharge command that greatly increases the output start range, then decreases the oil pressure command value, and further increases the decreased oil pressure command value gradually. To do.

In step S2, following the CL1 hydraulic pressure command in step S1, it is determined whether or not the second clutch CL2 at the start of the start control is in a slip state. If YES (CL2 slip state), the process proceeds to step S3. If NO (CL2 engagement state), the process proceeds to step S7.
The determination that the CL2 slip state is in step S2 is made, for example, at the time of starting when the second clutch CL2 is in the slip engagement state by selecting the “WSC mode”.

In step S3, following the determination of the CL2 slip state in step S2 or the determination that the target drive torque at the start of the start control in step S7 is positive, the injection timer time T1 from the start of the engine start control is determined. It is determined whether or not. If YES (injection timer time T1 has elapsed), the process proceeds to step 4. If NO (injection timer time T1 has not elapsed), the determination in step S3 is repeated.
Here, the “injection timer time T1” is a timer time from the start to the start of fuel injection, and is a time obtained by subtracting the ignition timer time T2 from the predicted torque generation time T0. “Torque generation predicted time T0” is a predicted time required for the actual engagement capacity to start to be generated after the engagement command is output to the first clutch CL1. The “ignition timer time T2” is a timer time from fuel injection to the start of ignition of the air-fuel mixture, and is a time necessary for forming the air-fuel mixture in the cylinder chamber by the injected fuel.

In step S4, following the determination that the injection timer time T1 has elapsed in step S3, the piston in the expansion stroke is selected from the plurality of pistons of the horizontal engine 2 that are stopped, and fuel is stored in the cylinder chamber of the selected piston. And proceeds to step S5.
Here, the “piston selection for expansion stroke” is selected based on the crank angle information from the crank angle sensor 92 of the horizontal engine 2.

  In step S5, following the fuel injection to the piston in the expansion stroke in step S4, it is determined whether or not the ignition timer time T2 has elapsed from the injection timer time T1. If YES (ignition timer time T2 has elapsed), the process proceeds to step 6. If NO (ignition timer time T2 has not elapsed), the determination in step S5 is repeated.

In step S6, following the determination that the ignition timer time T2 has elapsed in step S5, the mixture in the cylinder chamber of the piston injected with fuel in step S4 is ignited, and the process proceeds to step S13.
By this step S6, when the combustion assist is started, the ignition timing for the piston in the expansion stroke is the torque generation predicted time T0, which is the timer elapsed time (= T1 + T2) from the start of outputting the engagement command to the first clutch CL1. It will be when.

In step S7, following the determination that the CL2 slip state is in step S2, it is determined whether the target drive torque at the start of the start control is positive. If YES (the target drive torque is positive), the process proceeds to step S3. If NO (the target drive torque is negative), the process proceeds to step S8.
That is, when it is determined that the target drive torque at the start of the start control is positive, the same processing as that in the CL2 slip state at the start of the start control is performed.

  In step S8, following the determination that the target drive torque is negative in step S7, it is determined whether the CL2 slip-in time can be predicted during coasting. If YES (CL2 slip-in time can be predicted), the process proceeds to step S9. If NO (CL2 slip-in time cannot be predicted), the process proceeds to step S13.

In step S9, following the determination that the CL2 slip-in time can be predicted in step S8, it is determined whether or not the injection timer time T3 has elapsed since the completion of the precharge of the first clutch CL1. If YES (injection timer time T3 has elapsed), the process proceeds to step 10. If NO (injection timer time T3 has not elapsed), the determination in step S9 is repeated.
Here, the “injection timer time T3” is a timer time from the end of CL1 precharge to the start of fuel injection, and is a time obtained by subtracting the CL1 precharge time T5 and the ignition timer time T2 from the CL2 slip-in time T4. “CL2 slip-in time T4” is an estimated time required from the start of CL2 slip-in control of the second clutch CL2 to the CL2 slip-in determination. The “ignition timer time T2” is the timer time from fuel injection to the start of ignition of the air-fuel mixture, as in step S5, and is the time required to form the air-fuel mixture in the cylinder chamber by the injected fuel.

In step S10, following the determination that the injection timer time T3 has elapsed in step S9, fuel is injected into the cylinder chamber of the piston in the selected expansion stroke, the CL1 hydraulic pressure command is lowered, and the process proceeds to step S11.
Here, “piston selection for expansion stroke” is selected based on the crank angle information from the crank angle sensor 92 of the horizontally placed engine 2 as in step S4.

  In step S11, it is determined whether the ignition timer time T2 has elapsed from the injection timer time T3 following the fuel injection to the piston in the expansion stroke in step S10 and the decrease in the CL1 hydraulic pressure command. If YES (ignition timer time T2 has elapsed), the process proceeds to step 12. If NO (ignition timer time T2 has not elapsed), the determination in step S11 is repeated.

In step S12, following the determination that the ignition timer time T2 has elapsed in step S11, the air-fuel mixture in the cylinder chamber of the piston injected with fuel in step S10 is ignited, and the CL1 hydraulic pressure command is increased, and the process proceeds to step S13.
By this step S12, at the time of combustion assist start when the target drive torque is negative, the ignition timing of the piston in the expansion stroke is the timer elapsed time from the start of outputting the engagement command to the first clutch CL1 (= T5 + T3 + T2) However, when CL2 slip-in time T4 is reached.

  In step S13, following the determination that the ignition combustion in step S6 or step S12 or the CL2 slip-in time cannot be predicted in step S8, the engine speed is the initial explosion determination threshold value Ne1 of the horizontal engine 2. It is determined whether this is the case. If YES (engine speed ≧ Ne1), the process proceeds to step S14. If NO (engine speed <Ne1), the determination in step S13 is repeated.

  In step S14, following the determination in step S13 that the engine speed is greater than or equal to Ne1, fuel injection and ignition are performed on all cylinders of the horizontally mounted engine 2, and the process proceeds to step S15.

In step S15, following the fuel injection and ignition to all the cylinders in step S14, it is determined whether or not the engine speed is equal to or greater than the complete explosion determination threshold value Ne2 of the horizontal engine 2. If YES (engine speed ≧ Ne2), the process proceeds to the end. If NO (engine speed <Ne2), the process returns to step S14.
When the combustion assist start control process is completed from step S15, the first clutch CL1 is engaged, and then the second clutch CL2 is engaged, and the mode is changed from the “EV mode” to the “HEV mode”.

Next, the operation will be described.
The operation of the control apparatus for the FF hybrid vehicle of the first embodiment will be described separately for “combustion assist start control processing operation”, “combustion assist start control operation”, and “characteristic operation of combustion assist start control”.

[Combustion assist start control processing action]
Hereinafter, the combustion assist start control processing operation will be described based on the flowchart of FIG.

  When the engine is requested to start, such as when starting, and when the second clutch CL2 is in the slip state, the process proceeds from step S1 to step S2 to step S3 in the flowchart of FIG. In step S1, a CL1 hydraulic pressure command for hydraulically engaging the first clutch CL1 released in the “EV mode” is output. In step S3, it is determined whether or not an injection timer time T1 has elapsed since the start of engine start control. Then, when it is determined in step S3 that the injection timer time T1 has elapsed, the process proceeds to step S4, where a piston in the expansion stroke is selected from the plurality of pistons of the lateral engine 2 that are stopped, and the selected piston is selected. Fuel is injected into the cylinder chamber. If it is determined in step S5 that the ignition timer time T2 has elapsed from the injection timer time T1, the process proceeds to step S6, and the air-fuel mixture in the cylinder chamber of the piston injected with fuel in step S4 is ignited. Then, the process proceeds from step S6 to step S13. If it is determined in step S13 that the engine speed is equal to or greater than the initial explosion determination threshold value Ne1 of the horizontal engine 2, the process proceeds to step S14 and all cylinders of the horizontal engine 2 are processed. Fuel injection and ignition are performed. Thereafter, when it is determined in step S15 that the engine speed is equal to or greater than the complete explosion determination threshold value Ne2 of the horizontal engine 2, the routine proceeds to the end and the combustion assist start control is terminated. In other words, an explosion occurs in the cylinder chamber due to ignition in step S6, and the piston in the expansion stroke is pushed by the explosion energy, and combustion assist start control is performed to give the crankshaft combustion start torque in the engine rotation direction.

  When the engine start request is for driving, etc., and the second clutch CL2 is engaged and the target drive torque is positive, in the flowchart of FIG. 2, step S1, step S2, step S7, step S3 Proceed to Then, the same processing as the processing is performed when the second clutch CL2 is in the slip state. In other words, an explosion occurs in the cylinder chamber due to ignition in step S6, and the piston in the expansion stroke is pushed by the explosion energy, and combustion assist start control is performed to give the crankshaft combustion start torque in the engine rotation direction.

  When it is an engine start request during coasting, etc., when the second clutch CL2 is engaged, the target drive torque is negative, and the CL2 slip-in time can be predicted, the flowchart of FIG. Then, the process proceeds from step S1, step S2, step S7, step S8, and step S9. In step S9, if it is determined that the injection timer time T3 has elapsed since the end of precharge of the first clutch CL1, the process proceeds to step 10, and in step S10, fuel is supplied to the cylinder chamber of the piston in the selected expansion stroke. As the fuel is injected, the CL1 hydraulic pressure command is lowered. In step S11, if it is determined that the ignition timer time T2 has elapsed from the injection timer time T3, the process proceeds to step 12, and in step S12, the mixture in the cylinder chamber of the piston that has injected fuel in step S10 is changed. At the same time, the CL1 oil pressure command is raised. Then, the process proceeds from step S6 to step S13. If it is determined in step S13 that the engine speed is equal to or greater than the initial explosion determination threshold value Ne1 of the horizontal engine 2, the process proceeds to step S14 and all cylinders of the horizontal engine 2 are processed. Fuel injection and ignition are performed. Thereafter, when it is determined in step S15 that the engine speed is equal to or greater than the complete explosion determination threshold value Ne2 of the horizontal engine 2, the routine proceeds to the end and the combustion assist start control is terminated. That is, an explosion occurs in the cylinder chamber due to the ignition in step S12, and the piston in the expansion stroke is pushed by the explosion energy, and combustion assist start control is performed to give the crankshaft combustion start torque in the engine rotation direction.

  FIG. 2 is a flowchart of an engine start request for coasting, etc., when the second clutch CL2 is engaged, the target drive torque is negative, and the CL2 slip-in time cannot be predicted. In step S1, step S2, step S7, step S8, step S13. In step S13, if it is determined that the engine speed is equal to or greater than the initial explosion determination threshold value Ne1 of the horizontal engine 2, the process proceeds to step S14, where fuel injection and ignition are performed on all cylinders of the horizontal engine 2. Is called. Thereafter, when it is determined in step S15 that the engine speed is equal to or greater than the complete explosion determination threshold value Ne2 of the horizontal engine 2, the routine proceeds to the end and the combustion assist start control is terminated. That is, only when the CL2 slip-in time is unpredictable, the combustion assist start control is not performed, the motor generator 4 is used as a starter motor, and the horizontally placed engine 2 is cranked and started by the CL1 torque capacity. The engine start control is performed.

[Combustion assist start control action]
Hereinafter, the combustion assist start control operation of the first embodiment is referred to as “technical background (FIG. 3)”, “combustion assist start control operation at start (FIG. 4)”, “combustion assist start at the time of depressing start from R / L” The explanation will be divided into “control action (FIG. 5)” and “combustion assist start control action at the time of depressing start from the coast (FIG. 6)”.

(Technical background)
In the 1-motor / 2-clutch drive system, when the engine is started with the motor generator as the starter motor, the fastening capacity of the first clutch CL1 is increased, and the motor torque corresponding to the CL2 fastening capacity is applied to the crankshaft of the engine for cranking. Is going. When analyzing the characteristics of the motor torque with respect to the engine crankshaft rotation speed at this time, the motor torque suddenly increases at the moment when the engine crankshaft starts rotating, and when the crankshaft starts rotating, the motor torque becomes low torque. Transition to.

  The present inventors pay attention to the fact that the motor torque suddenly increases at the moment when the crankshaft of the engine starts to rotate, and invents the combustion assist start control that generates the combustion start torque of the engine in accordance with the timing when the motor torque rapidly increases. did. That is, by injecting and igniting the piston in the expansion stroke and generating combustion starting torque, motor torque shared by the motor generator can be reduced among cranking torque necessary for engine starting.

  Furthermore, in realizing the combustion assist start control, it is important to properly set the injection and ignition timing from the start of the CL1 command. That is, if the CL1 torque response timing and the engine ignition timing do not match well, the combustion assist torque for the required cranking torque cannot be secured, and the engine speed cannot be increased. When the engine speed increases slowly, the start response deteriorates (generation of lag and ledge).

  Therefore, the initial value setting of the torque generation predicted time T0, which is the CL1 torque response timing at which the actual engagement capacity starts to be generated after the engagement command is output to the first clutch CL1, is taken as an example in the case of the CL2 slip state at the start of the start. This will be described with reference to FIG.

  First, the variation factors of the first clutch CL1 include response time variation (clearance, hydraulic pressure, trial times, μ learning value, oil temperature) and torque variation. Among these, the “clearance and hydraulic pressure variation” is large as shown in FIG. 3 (for example, 0.15 to 0.25 sec). “Trial times, μ learning value variation” is small as shown in FIG. 3 (for example, 0.04 sec). “Torque variation” is large as shown in FIG. 3 (for example, ± 15 Nm). Therefore, when considering the variation range between the time axis and the torque axis, the “CL1 response median value” of the CL1 torque characteristic becomes the solid line characteristic of FIG. As for “oil temperature variation”, there is no problem of variation due to oil temperature if an oil temperature condition equal to or higher than the set oil temperature is given as a permission condition for combustion assist start control.

  On the other hand, the combustion starting torque (= engine torque) generated by fuel injection and ignition to the piston in the expansion stroke increases as a result of the explosion when the mixture is ignited, as shown in FIG. After the peak ("engine torque response center"), the torque decreases.

  Therefore, the “engine torque response center” is set slightly later than the “CL1 response median value”, and the estimated torque generation time in consideration of the combustion start torque generation time (for example, ± 60 msec from the engine torque response center). Set the initial value of T0. Then, when this estimated torque generation time T0 is set as a reference time and the injection timer time T3 and the ignition timer time T2 from the start of the CL1 command are set, the CL1 torque response timing and the engine ignition timing regardless of variations in the first clutch CL1. Was found to fit well. When it can be predicted that the CL1 torque response timing and the ignition timing do not match, it is necessary to set the necessary cranking torque by using only the CL1 torque by separating the conditions in advance.

(Combustion assist start control action at start-up)
FIG. 4 is a time chart when the combustion assist start control is performed at the start (CL2 slip at the start of start).
In FIG. 4, time t0 is the start time, time t1 is the fuel injection time, time t2 is the ignition time (combustion start torque generation time), and time t3 is the combustion start torque end time.
When the start is started and the second clutch CL2 is in the slip state, CL1 precharge time> CL2 slip-in time. In starting at the time of starting, fuel is injected into the cylinder chamber of the piston in the expansion stroke at time t1 when the injection timer time T1 has elapsed after starting at time t0. At time t2 when the ignition timer time T2 has elapsed from the injection timer time T1 (t0 to t2 are torque generation prediction times T0), the air-fuel mixture in the cylinder chamber of the fuel-injected piston is ignited and combustion start torque (FIG. 4). The portion indicated by hatching in FIG. Then, at time t3, the generation of the combustion starting torque ends. That is, an explosion occurs in the cylinder chamber by ignition at time t2, and the piston in the expansion stroke is pushed by the explosion energy, and combustion starting torque in the engine rotation direction is applied to the crankshaft.
Thus, at the start of the start in the CL2 slip state, the horizontal engine 2 is set by adding the combustion start torque generated at the time t2 to the CL1 torque (= motor torque) that rises at the timing that coincides with or near the time t2. Combustion assist start control for cranking is performed.

(Combustion assist start control action when starting from R / L)
FIG. 5 is a time chart when the combustion assist start control is performed at the time of depressing start from R / L (load / load) (CL2 LU & motor torque positive at start of start).
In FIG. 5, time t0 is the start time, time t1 is the fuel injection time, time t2 is the ignition time (combustion start torque generation time), and time t3 is the combustion start torque end time.
When the second clutch CL2 is engaged and the motor torque is positive at the start of depressing from R / L, CL1 precharge time ≈ CL2 slip-in time. At the time of depressing start from R / L, after starting at time t0, at time t1 when the injection timer time T1 has elapsed, fuel is injected into the cylinder chamber of the piston in the expansion stroke. Then, precharge of the first clutch CL1 and slip-in control of the second clutch CL2 are performed during the period from the injection timer time T1 until the ignition timer time T2 elapses. At time t2 when the ignition timer time T2 has elapsed from the injection timer time T1 (t0 to t2 is the predicted torque generation time T0), the air-fuel mixture in the cylinder chamber of the fuel-injected piston is ignited and combustion start torque (FIG. 5). The portion indicated by hatching in FIG. Then, at time t3, the generation of the combustion starting torque ends. That is, an explosion occurs in the cylinder chamber by ignition at time t2, and the piston in the expansion stroke is pushed by the explosion energy, and combustion starting torque in the engine rotation direction is applied to the crankshaft.
In this way, at the time of depressing start from R / L, the horizontal engine 2 is obtained by adding the combustion start torque generated at time t2 to the CL1 torque (= motor torque) that rises at the timing coincident with or close to time t2. Combustion assist start control for cranking is performed.

(Combustion assist start control action when starting from the coast)
FIG. 6 is a time chart when combustion assist start control is performed at the start of depression from the coast (CL2 LU & motor torque negative at start of start).
In FIG. 6, time t0 is the start time, time t1 is the CL1 precharge end time, time t2 is the fuel injection time, time t3 is the ignition time (combustion start torque generation time), and time t4 is the combustion start torque end time. .
When the second clutch CL2 is engaged and the motor torque is negative at the start of stepping from the coast, CL1 precharge time <CL2 slip-in time. At the start of stepping from this coast, after starting at time t0, it becomes time t1 when the CL1 precharge time T5 has elapsed, and further, when time t2 has passed the injection timer time T3 from time t1, Fuel is injected into the cylinder chamber of the piston in the stroke. At time t3 when ignition timer time T2 has elapsed from injection timer time T3 (t0 to t3 are slip-in times), the air-fuel mixture in the cylinder chamber of the fuel-injected piston is ignited, and combustion start torque (hatching in FIG. 6) Occurrence of the portion indicated by) starts. Then, at time t4, the generation of the combustion start torque ends. That is, an explosion occurs in the cylinder chamber by ignition at time t3, and the piston in the expansion stroke is pushed by the explosion energy, and combustion start torque in the engine rotation direction is applied to the crankshaft.
Thus, at the time of depressing start from the coast, the horizontal engine 2 is clicked by adding the combustion start torque generated at time t3 to the CL1 torque (= motor torque) that rises at a timing that coincides with or close to time t3. The combustion assist start control for ranking is performed.

[Characteristics of combustion assist start control]
In the first embodiment, when starting the engine, the combustion is performed by adding the combustion starting torque generated by the fuel injection and ignition to the piston in the expansion stroke among the stopped engine pistons to the motor torque due to the engagement capacity of the first clutch CL1. The assist start control is performed.
That is, when the engine is started, as is clear from the comparison of the rotational speed characteristics before and after the improvement in FIG. 7, by increasing the engine rotational speed by the combustion starting torque in the horizontal engine 2, The rotation synchronization timing of the horizontal engine 2 becomes early. As a result, as is apparent from the comparison of the acceleration characteristics before and after improvement in FIG. 7, the front and rear G rises quickly (improves the start response).
The engine start request is issued when the motor torque in the EV mode becomes a torque obtained by subtracting the motor torque used for starting the engine from the maximum motor torque. On the other hand, the motor torque (= engagement capacity of the first clutch) used for starting the engine can be lowered by the amount corresponding to the combustion starting torque from the horizontally placed engine 2. Therefore, as is apparent from the comparison of the motor characteristics before and after improvement in FIG. 8, after the improvement, the horizontally placed engine 2 is stopped, and the selection in the “EV mode” using only the motor generator 4 as the travel drive source The area expands (improves fuel economy).
In this way, by starting the engine by the combustion assist start control, the start response can be improved and the fuel consumption can be improved.

In the first embodiment, the time required for the actual engagement capacity to start after the engagement command is output to the first clutch CL1 is assumed to be the torque generation prediction time T0. In the combustion assist start control, the ignition timing of the piston in the expansion stroke is set to be the time when the timer elapsed time from the start of outputting the engagement command to the first clutch CL1 becomes the torque generation prediction time T0. .
That is, the CL1 torque generation time required for the first clutch CL1 to start generating the CL1 torque is predicted in advance. At the time of combustion assist start control, the ignition timing for the piston in the expansion stroke is adjusted to this torque generation prediction time T0.
Therefore, the coincidence between the CL1 torque generation timing of the first clutch CL1 and the ignition timing of the horizontal engine 2 is increased, and the combustion start torque necessary for starting cranking is ensured by the optimization of the ignition timing.

In Example 1, when the time from the start of fuel injection to the start of fuel injection is the injection timer time T1, and the time from the fuel injection to the start of ignition of the air-fuel mixture is the ignition timer time T2, the ignition timer time T2 is Therefore, the time required for forming the air-fuel mixture in the cylinder chamber is set. The injection timer time T1 is set to a time obtained by subtracting the ignition timer time T2 from the predicted torque generation time T0.
That is, the combustion assist start control is performed by the timer management that determines the injection timer time T1 and the ignition timer time T2 with the predicted torque generation time T0 as the reference time.
Accordingly, the combustion start torque necessary for starting cranking is ensured by optimizing the interval between the fuel injection timing and the ignition timing.

In the first embodiment, when the second clutch CL2 is in the slip state at the start of starting, the injection timer time T1 and the ignition timer time T2 are applied.
That is, the fact that the second clutch CL2 is in the slip state at the start of the start is a suitable condition for matching the CL1 torque generation timing with the ignition timing.
Accordingly, the combustion assist start control is applied only to conditions suitable for matching the CL1 torque generation timing and the ignition timing.

In the first embodiment, the second clutch CL2 is in the engaged state at the start of starting, but when the target drive torque is positive, the injection timer time T1 and the ignition timer time T2 are applied.
That is, when the second clutch CL2 is engaged at the start of starting, but the target drive torque is positive, the CL2 slip-in control can be performed in a short time due to the decrease in the CL2 torque capacity and the increase in the motor torque. That is, it is a good condition for matching the CL1 torque generation timing and the ignition timing.
Therefore, the combustion assist start control is applied only under favorable conditions to match the CL1 torque generation timing and the ignition timing.

In the first embodiment, when the second clutch Cl2 is engaged at the start of the start and the target drive torque is negative, the slip-in time T4 required from the start of slip-in control of the second clutch CL2 to the slip-in determination is predicted. It is determined whether or not it is possible (S8 in FIG. 2). When the condition that the slip-in time can be predicted is satisfied, the combustion assist start control is performed by timer management based on the predicted slip-in time T4 and the precharge end time of the first clutch CL1 (time t1 in FIG. 6).
That is, when the target drive torque (= motor torque) is negative, it is difficult to accurately predict the CL2 slip-in time and determine the ignition timer time T2. On the other hand, there is a demand for applying combustion assist start control regardless of the driving scene.
On the other hand, when the condition that the slip-in time can be predicted is satisfied, the combustion assist start control is performed, so that a traveling scene to which the combustion assist start control is applied is enlarged.

Next, the effect will be described.
In the control apparatus for the FF hybrid vehicle of the first embodiment, the following effects can be obtained.

(1) Drive system in which the engine (horizontal engine 2) and motor (motor generator 4) are used as drive sources, and the first clutch CL1 is interposed between the engine (horizontal engine 2) and motor (motor generator 4). In a hybrid vehicle (FF hybrid vehicle) with
When there is an engine start request, a controller (hybrid control module 81) is provided that uses a motor (motor generator 4) as a starter motor and controls the engagement of the first clutch CL1 to start the engine (horizontal engine 2).
When the engine is started, the controller (hybrid control module 81) adds the combustion starting torque generated by fuel injection and ignition to the piston in the expansion stroke among the stopped engine pistons, to the motor torque due to the engagement capacity of the first clutch CL1. Perform combustion assist start control for cranking.
Thus, by performing engine start by combustion assist start control, it is possible to improve the start response and improve the fuel consumption.

(2) The controller (hybrid control module 81) sets the time required for the actual engagement capacity to start to be generated after outputting the engagement command to the first clutch CL1 as the torque generation prediction time T0. The ignition timing for the piston in the stroke is assumed to be when the elapsed time of the timer from the start of starting outputting the engagement command to the first clutch CL1 becomes the predicted torque generation time T0.
For this reason, in addition to the effect of (1), the coincidence between the CL1 torque generation timing of the first clutch CL1 and the ignition timing of the engine (horizontal engine 2) is increased, and cranking is started by optimizing the ignition timing. Necessary combustion starting torque can be secured.

(3) The controller (hybrid control module 81) determines that the time from the start of fuel injection to the start of fuel injection is the injection timer time T1, and the time from the fuel injection to the start of ignition of the air-fuel mixture is the ignition timer time T2. The timer time T2 is a time required to form an air-fuel mixture in the cylinder chamber with the injected fuel, and the injection timer time T1 is a time obtained by subtracting the ignition timer time T2 from the predicted torque generation time T0.
For this reason, in addition to the effect of (2), the combustion start torque necessary for starting cranking can be ensured by optimizing the interval between the fuel injection timing and the ignition timing.

(4) Between the motor (motor generator 4) and the drive wheels (left and right front wheels 10L, 10R), a second clutch CL2 that is slip-engaged when the engine is started is interposed.
The controller (hybrid control module 81) applies the injection timer time T1 and the ignition timer time T2 when the second clutch CL2 is in the slip state at the start of starting.
For this reason, in addition to the effect of (3), the combustion assist start control can be applied only to conditions suitable for matching the CL1 torque generation timing and the ignition timing.

(5) The controller (hybrid control module 81) applies the injection timer time T1 and the ignition timer time T2 when the second clutch CL2 is in the engaged state at the start of starting but the target drive torque is positive.
For this reason, in addition to the effect of (4), the combustion assist start control can be applied only under favorable conditions for matching the CL1 torque generation timing and the ignition timing.

(6) The controller (hybrid control module 81), when the second clutch Cl2 is engaged at the start of the start and the target drive torque is negative, from the start of slip-in control of the second clutch CL2 to the slip-in determination. When the condition that the required slip-in time T4 can be predicted is satisfied, combustion assist start control is performed by timer management based on the predicted slip-in time T4 and the precharge end time of the first clutch CL1 (time t1 in FIG. 6).
Therefore, in addition to the effect of (4) or (5), when the condition that the slip-in time can be predicted is satisfied, the combustion scene to which the combustion assist start control is applied can be expanded by performing the combustion assist start control.

  As mentioned above, although the control apparatus of the hybrid vehicle of this invention was demonstrated based on Example 1, it is not restricted to this Example 1 about a concrete structure, The invention which concerns on each claim of a claim Design changes and additions are permitted without departing from the gist of the present invention.

  In the first embodiment, an example in which a belt type continuously variable transmission 6 in which a belt 6c is stretched between the primary pulley 6a and the secondary pulley 6b and the primary pulley pressure Ppri and the secondary pulley pressure Psec are used as the transmission hydraulic pressure is used as the transmission. . However, as an example of a transmission, an automatic transmission called step AT, an AMT that automatically shifts with a manual transmission structure, a DCT that has two clutches and that automatically shifts with a manual transmission structure, and the like may be used. good.

  In the first embodiment, an example in which the control device of the present invention is applied to an FF hybrid vehicle with a drive format of 1 motor and 2 clutches is shown. However, the control device of the present invention can also be applied to an FR hybrid vehicle or a hybrid vehicle other than the one motor / two clutch drive type. In short, the present invention can be applied to a hybrid vehicle including an engine and a motor as a drive source and a drive system in which a first clutch is interposed between the engine and the motor.

2 Horizontal engine (engine)
3 First clutch 4 Motor generator (motor)
5 Second clutch 6 Belt type continuously variable transmission 10L, 10R Left and right front wheels (drive wheels)
14 Main oil pump 81 Hybrid control module (controller)
82 Engine control module 83 Motor controller 84 CVT control unit 85 Brake control unit 86 Lithium battery controller

Claims (6)

In a hybrid vehicle including an engine and a motor as a drive source, and having a drive system in which a first clutch is interposed between the engine and the motor,
When there is an engine start request, the motor is a starter motor, and a controller for starting the engine by controlling the engagement of the first clutch is provided,
The controller cranks the engine by adding the combustion starting torque generated by fuel injection and ignition to the piston in the expansion stroke among the stopped engine pistons to the motor torque based on the engagement capacity of the first clutch when starting the engine. A control device for a hybrid vehicle, characterized by performing start control. In the hybrid vehicle control device according to claim 1,
The controller sets a time required for the actual engagement capacity to start to be generated after outputting the engagement command to the first clutch as a torque generation prediction time, and sets the ignition timing to the piston in the expansion stroke at the time of combustion assist start control. A control apparatus for a hybrid vehicle, characterized in that a timer elapsed time from the start of outputting an engagement command to the first clutch becomes the torque generation predicted time. In the hybrid vehicle control device according to claim 2,
When the time from the start to the start of fuel injection is the injection timer time T1, and the time from the fuel injection to the start of ignition to the air-fuel mixture is the ignition timer time T2, the controller sets the ignition timer time T2 to the injected fuel And a time required for forming the air-fuel mixture in the cylinder chamber, and the injection timer time T1 is a time obtained by subtracting the ignition timer time T2 from the predicted torque generation time. . In the hybrid vehicle control device according to claim 3,
Between the motor and the drive wheel, a second clutch that is slip-engaged when the engine is started is interposed,
The controller applies the injection timer time T1 and the ignition timer time T2 when the second clutch is in a slip state at the start of starting. In the hybrid vehicle control device according to claim 4,
The controller applies the injection timer time T1 and the ignition timer time T2 when the second clutch is in an engaged state at the start of starting but the target drive torque is positive. . In the control device for a hybrid vehicle according to claim 4 or 5,
The controller can predict a slip-in time required from the start of slip-in control of the second clutch to the slip-in determination when the second clutch is in an engaged state at the start of starting and the target drive torque is negative. When the condition is satisfied, the combustion assist start control is performed by timer management based on a predicted slip-in time and a precharge end time of the first clutch.