JP2013193555A - Controller of hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress or prevent overheating of an injector and to stabilize combustion during recovery from fuel cutting when fuel is cut in a state in which the injector is apt to rise in temperature.SOLUTION: A controller 100 of a hybrid vehicle, which uses an engine 1 and a motor as a driving source generating driving power for travel and is provided with a throttle valve 13 and the injector 18 in an intake channel 11 of the engine, makes the opening degree of the throttle valve 13 larger than that in a stationary time when fuel is cut in a state in which an injector 18 is apt to rise in temperature. In this case, a nozzle of the injector 18 is cooled with intake air flowing in through the throttle valve 13.

Description

  The present invention uses a hybrid vehicle having an engine (internal combustion engine) and a motor as a drive source for generating a driving force for travel, and a throttle valve and an injector (fuel injection valve) installed in an intake passage of the engine. The present invention relates to a control device.

  In general, a port fuel injection system (PFI) enables precise mixture control by individually injecting fuel into an intake port of each cylinder of an engine.

  For example, if fuel cut is performed for a long time after the engine is operated at a high load, fuel such as gasoline is likely to vaporize inside the injector. In such a situation, if the fuel cut is terminated and the fuel injection is resumed, vapor is injected from the injector, and there is a possibility that poor combustion occurs.

  In the first place, when the engine is operated at a high load as described above, not only the engine becomes high temperature, but also the intake air temperature becomes high as the atmospheric temperature in the engine compartment becomes high. On the other hand, during fuel cut, since fuel does not flow inside the injector, cooling by fuel circulation cannot be expected, and since the throttle opening is small, cooling of the injector nozzle by intake air cannot be expected. For this reason, the injector is overheated, and the fuel present in the injector is easily vaporized.

  For example, Patent Document 1 states that “in an internal combustion engine having a supercharger with an electric motor and an in-cylinder injector, the cylinder head is superheated and the exhaust purification catalyst is superheated. It is described that the exhaust purification catalyst is cooled from the cylinder head by operating the attached electric motor to perform scavenging.

  Further, for example, in Patent Document 2, “in a hybrid vehicle having a PFI in an internal combustion engine, the fuel pressure in the delivery pipe is increased by driving the fuel pump without starting the internal combustion engine by motoring when the internal combustion engine is stopped at a high temperature. It is described that by maintaining the vapor pressure not lower than the vapor pressure, the fuel such as gasoline is prevented from vaporizing inside the delivery pipe.

JP 2004-124865 A JP 2010-137596 A

  In the conventional example according to Patent Document 1, overheating of the exhaust system is a problem, and in order to solve it, scavenging is performed by an electric motor attached to the supercharger, and overheating of the injector during fuel cut is a problem. It is not something to do.

  Further, in the conventional example according to Patent Document 2, although fuel vaporization in the delivery pipe is an issue, as a means for solving the problem, the fuel pressure in the delivery pipe is not reduced below the vapor pressure by driving the fuel pump. I am doing so. That is, overheating of the injector during fuel cut is not a problem.

  In view of such circumstances, the present invention uses an engine and a motor as a drive source for generating a driving force for traveling, and a hybrid vehicle having a configuration in which a throttle valve and an injector are installed in an intake passage of the engine. In a control device, when fuel cut is performed in a state where the temperature of the injector is likely to rise, it is possible to suppress or prevent overheating of the injector, and to stabilize combustion at the time of return from the fuel cut.

  The present invention is a control device for a hybrid vehicle having a configuration in which an engine and a motor are used as a drive source for generating a driving force for traveling, and a throttle valve and an injector are installed in an intake passage of the engine, When the fuel cut is performed in a situation where the temperature of the injector is likely to rise, the throttle valve opening is made larger than in the normal state.

  In this configuration, the nozzle of the injector is cooled by the intake air flowing through the throttle valve. As a result, it is possible to suppress or prevent overheating of the injector, so that vaporization of fuel inside the injector is suppressed or prevented. Therefore, it becomes possible to stabilize the combustion when returning from the fuel cut.

  The situation where the temperature of the injector is likely to rise is a case where the engine coolant temperature is equal to or higher than a predetermined value and the intake air temperature of the engine is equal to or higher than a predetermined value.

  Preferably, the control device for the hybrid vehicle may be configured to control a braking force generating element for applying a braking force to the vehicle in addition to the opening degree control of the throttle valve.

  In this configuration, if the throttle opening is relatively large during the fuel cut as described above, the cooling action of the injector is improved, but the deceleration effect by the engine brake is lost, so that the braking force is applied to the vehicle by the braking force generating element. To give. Thereby, since the vehicle is decelerated, overheating of the injector can be suppressed or prevented without sacrificing the decelerating action.

  Preferably, the braking force generation element is the motor, and when the braking force is required, the motor can be configured to generate a negative torque by performing a regenerative operation.

  In this configuration, if the throttle opening is relatively large during the fuel cut as described above, the cooling effect of the injector is improved, but the deceleration effect by the engine brake is lost, so by generating negative torque from the motor, A braking force is applied to the vehicle. Thereby, since the vehicle is decelerated, overheating of the injector can be suppressed or prevented without sacrificing the decelerating action.

  Preferably, the hybrid vehicle control device determines that the injector is likely to rise in temperature when the coolant temperature of the engine is equal to or higher than a predetermined value and the intake air temperature of the engine is equal to or higher than a predetermined value. A determination unit, a fuel cut determination unit that determines whether or not a fuel cut is being performed, and the situation determination unit determines that the temperature is likely to rise, and the fuel cut determination unit determines that the fuel cut When the target throttle opening is set to be larger than the target throttle opening at the time of steady operation, the throttle is set to match the actual throttle opening with the set target throttle opening. And a coping unit that operates the valve.

  Here, functional elements realized by the control device are specified. This identification makes it possible to construct control logic for carrying out the present invention relatively easily.

  Preferably, the hybrid vehicle control device determines that the injector is likely to rise in temperature when the coolant temperature of the engine is equal to or higher than a predetermined value and the intake air temperature of the engine is equal to or higher than a predetermined value. A determination unit; a fuel cut determination unit that determines whether or not a fuel cut is being performed; an execution time determination unit that determines whether or not the execution time of the fuel cut has exceeded a predetermined value; and the situation determination The fuel cut determination unit determines that the fuel cut is being executed, and the execution time determination unit determines that a predetermined value or more has elapsed. The target throttle opening is set to be larger than the target throttle opening at the steady state, and the actual throttle opening is set equal to the set target throttle opening. Actuating said throttle valve so as to include the address portion may be configured.

  In this configuration, it is determined whether or not fuel is likely to vaporize inside the injector based on the fuel cut execution time as the fuel cut is executed in a situation where the temperature of the injector is likely to rise. In addition, when the fuel in the injector is likely to vaporize, the processing by the coping unit is executed. As described above, when the execution permission conditions for the processing of the coping unit are strict, even if it is not necessary to execute the processing of the coping unit, it is possible to eliminate the waste of execution. .

  Preferably, the coping unit may be configured to generate a negative torque by causing the motor to perform a regenerative operation in addition to the setting of the target throttle opening.

  The normal time is defined as a time when the situation determination unit determines that “the situation is not easy to raise the temperature” and the fuel cut determination unit determines that “the fuel cut is being executed”. Further, as the target throttle opening at the steady state, the oil value during fuel cut is set to the learning value acquired by the learning unit that periodically learns the intake air amount at the throttle opening for keeping the engine at idling speed. It is set by adding a raising correction value of the intake air amount for suppressing consumption. As described above, when the target throttle opening at the normal time is specified, the target throttle opening at the high temperature condition becomes clear.

  The present invention relates to a hybrid vehicle control device in which an engine and a motor are used as a drive source for generating a driving force for traveling, and a throttle valve and an injector are installed in an intake passage of the engine. When fuel cut is performed in a situation where the temperature is high, overheating of the injector can be suppressed or prevented.

  As a result, fuel vaporization inside the injector can be suppressed or prevented, so that combustion can be stabilized when returning from the fuel cut, thereby contributing to improved drivability. become.

1 is a schematic configuration diagram showing an embodiment of a control apparatus for a hybrid vehicle according to the present invention. It is a figure which shows schematic structure of the engine of FIG. It is a flowchart for demonstrating the control action in one Embodiment of this invention. It is a timing chart for demonstrating the control action in one Embodiment of this invention. It is other embodiment of the control apparatus of the hybrid vehicle which concerns on this invention, and has shown the flowchart for demonstrating control operation | movement.

  BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the accompanying drawings.

  1 to 4 show an embodiment of the present invention. In this embodiment, a front wheel drive vehicle, that is, a hybrid vehicle of a front engine / front drive (FF) type is illustrated. The hybrid vehicle to which the present invention is applied is not limited to a front-wheel drive vehicle, but may be a vehicle of another drive system such as a rear-wheel drive vehicle or a four-wheel drive vehicle.

-Overview of hybrid system-
As shown in FIG. 1, the hybrid vehicle in this embodiment includes an engine 1, a motor generator MG1, a motor generator MG2, a reduction mechanism 4, a power split mechanism 5, an inverter 6, an HV battery 7, and the like. Since these basic configurations are the same as known configurations, the portions not directly related to the present invention will be briefly described.

  The engine 1 is controlled by an engine control computer 100. The engine control computer 100 controls the engine 1 by controlling the intake air amount (throttle opening), fuel injection amount, ignition timing, and the like based on an accelerator opening corresponding to an accelerator pedal depression amount (not shown). To control the operation.

  Motor generators MG1 and MG2 are AC synchronous motors that generate power when the rotor is rotated by three-phase AC, and function not only as motors but also as generators.

  Motor generator MG1 and motor generator MG2 are controlled by power management control computer 200. The power management control computer 200 controls the inverter 6 via the MG-ECU 8 to cause the motor generators MG1 and MG2 to perform a regenerative operation or a power running (assist) operation. The regenerative power is charged to the HV battery 7 via the inverter 6.

  The motor generator MG1 coupled to the power split mechanism 5 often operates as a generator in many cases, and therefore may be simply referred to as “generator”. Motor generator MG1 is also used as a starter motor that performs cranking when engine 1 is started. Further, the motor generator MG2 coupled to the reduction mechanism 4 mainly operates as an electric motor, and therefore may be simply referred to as a “motor”.

  The reduction mechanism 4 is composed of, for example, a known planetary gear mechanism, and the power generated by the engine 1 and the motor generators MG1 and MG2 is driven forward to a drive wheel (front wheel in this embodiment) 10 via a differential 9 and an axle. Force or reverse drive force is transmitted, or the rotational force of the drive wheel 10 is transmitted to the engine 1 or the motor generators MG1, MG2.

  The power split mechanism 5 is constituted by, for example, a known planetary gear mechanism, and distributes the power generated by the engine 1 to the rotation shaft of the motor generator MG2 (connected to the drive wheels 10) and the rotation shaft of the motor generator MG1. For reference, among each component of power split device 5, the ring gear is coupled to the rotation shaft of motor generator MG2, the sun gear is coupled to the rotation shaft of motor generator MG1, and the carrier is coupled to the output shaft of engine 1. . This power split mechanism 5 also functions as a continuously variable transmission by controlling the rotation speed of motor generator MG2.

  Inverter 6 is a power exchange device that converts a direct current of HV battery 7 and a three-phase alternating current of motor generator MG1 and motor generator MG2. HV battery 7 stores electric power for driving motor generators MG1, MG2. The inverter 6 is driven and controlled by the power management control computer 200.

  In this hybrid system, based on the required torque, target engine output, target motor torque, etc., control is performed to drive the drive wheels 10 using either one or both of the engine 1 and the motor generator MG2 as a power source. For example, in a region where the engine efficiency is low, such as when starting or running at a low speed, the engine 1 is stopped and the drive wheels 10 are driven by the power of only the motor generator MG2. Further, during normal traveling, the engine 1 is operated and the drive wheels 10 are driven by the power of the engine 1. Further, at the time of high load such as full-open acceleration, in addition to the power of engine 1, electric power is supplied from HV battery 7 to motor generator MG2, and the power from motor generator MG2 is added as auxiliary power.

-Outline of the engine-
A schematic configuration of the engine 1 will be described with reference to FIG. Although the engine 1 exemplified in this embodiment is an in-line four-cylinder engine, only one cylinder of the engine 1 is shown in FIG. The engine 1 is a four-cycle gasoline engine that repeats intake, compression, explosion (expansion), and exhaust strokes. For example, the ignition order is the first cylinder (# 1) → the third cylinder (# 3) → the fourth cylinder. (# 4) → 2nd cylinder (# 2).

  An intake passage 11 and an exhaust passage 12 are connected to the cylinder 1 a of the engine 1. The intake passage 11 includes an intake port 11a of a cylinder head (not shown) and an intake pipe (intake manifold) 11b with a surge tank. The intake passage 11 is provided with an air cleaner 2, a hot-wire air flow meter 30, an intake air temperature sensor 31 (built in the air flow meter 30), an electronically controlled throttle valve 13, and the like.

  The throttle valve 13 adjusts the intake air amount of the engine 1 and is driven by a throttle motor 14. The opening degree of the throttle valve 13 is detected by a throttle position sensor 33.

Further, the exhaust passage 12 includes a cylinder head exhaust port 12a and an exhaust pipe (exhaust manifold) 12b (not shown). The exhaust passage 12 is provided with, for example, an O ₂ sensor 34 and a catalytic converter 15 such as a three-way catalyst. The O ₂ sensor 34 outputs a detection signal corresponding to the oxygen concentration in the exhaust gas to the engine control computer 100.

  Each cylinder 1a of the engine 1 is provided with a spark plug 16. The ignition timing of the spark plug 16 is adjusted by an igniter 17.

  An injector (fuel injection valve) 18 is installed in the intake port 11 a of the intake passage 11. In this embodiment, PFI is taken as an example. The injector 18 is installed in such a posture as to inject fuel toward the opening closer to the cylinder 1a of the intake port 11a. A nozzle (not shown) at the tip of the injector 18 is disposed so as to be exposed in the intake port 11a.

  High pressure fuel is supplied to the injectors 18 and fuel is injected from each of the injectors 18 into the intake port 11a of the intake passage 11 to form an air-fuel mixture in the cylinder 1a. The air-fuel mixture is ignited by the spark plug 16 and burned in the cylinder 1a. The combustion of the air-fuel mixture in the cylinder 1a causes the piston 19 to reciprocate and the crankshaft 20 to rotate.

  In order to start engine 1, crankshaft 20 is rotationally driven by motor generator MG1 (cranking). When the air-fuel mixture is combusted in the cylinder 1a of the engine 1, the piston 19 is reciprocated, and the reciprocating motion of the piston 19 is converted into rotation of the crankshaft 20 by the connecting rod 21.

  The engine control computer 100 recognizes the rotational angle, rotational speed, rotational speed, and the like of the crankshaft 20 of the engine 1 based on the output signal of the crank position sensor 36. The crank position sensor 36 is a digital encoder that combines a signal rotor 36a and a non-contact sensor 36b. The signal rotor 36 a is attached to the crankshaft 20. A plurality of teeth (protrusions) are provided at equal angles on the outer peripheral surface of the signal rotor 36a, but a missing tooth portion in which, for example, two teeth (arbitrary number) are eliminated is provided in the predetermined outer peripheral region. This missing tooth portion serves as a mark for detecting the top dead center (TDC) of each cylinder 1a of the engine 1.

  An intake valve 22 is provided in the intake port 11a of the intake passage 11, and when the intake valve 22 is opened and closed by an intake camshaft 24, the intake passage 11 and the cylinder 1a are communicated or blocked. Further, an exhaust valve 23 is provided in the exhaust port 12a of the exhaust passage 12, and the exhaust passage 12 and the cylinder 1a are communicated or blocked by opening and closing the exhaust valve 23 by an exhaust camshaft 25. .

  The intake camshaft 24 and the exhaust camshaft 25 are rotationally driven by the rotational power of the crankshaft 20 being transmitted from a chain or belt (not shown). The intake camshaft 24 and the exhaust camshaft 25 rotate once when the crankshaft 20 rotates twice.

-Outline of control device-
The engine control computer 100 and the power management control computer 200 are not shown in detail in their internal configurations, but all have a CPU (central processing unit), ROM (program memory), RAM (data memory), and backup RAM (nonvolatile). Memory) or the like.

  The ROM stores various control programs, maps that are referred to when the various control programs are executed, and the like. The CPU executes arithmetic processing based on various control programs and maps stored in the ROM. The RAM is a memory for temporarily storing calculation results in the CPU, data input from each sensor, and the like. The backup RAM is a non-volatile memory for storing data to be saved when the engine 1 is stopped. is there. The ROM, CPU, RAM, and backup RAM are connected to each other via a bus.

  The engine control computer 100 and the power management control computer 200 are connected so that, for example, information necessary for engine control and motor generator control can be transmitted and received.

The input interface of the engine control computer 100 includes an air flow meter 30, an intake air temperature sensor 31, an engine temperature (coolant temperature) sensor 32, a throttle opening sensor (throttle position sensor) 33, an O ₂ sensor 34, a crank position sensor 36, and the like. Is at least connected. To the output interface of the engine control computer 100, a throttle motor 14 of a throttle valve 13, an igniter 17 of an ignition plug 16, an injector 18 and the like are connected.

  The input interface of the power management control computer 200 is connected to at least an accelerator opening sensor (accelerator position sensor) 35, an idle switch 37, a wheel speed sensor 38, and the like.

  The power management control computer 200 detects the depression amount of an accelerator pedal (not shown) based on the output of the accelerator opening sensor 35, and the depression amount of the accelerator pedal (not shown) is zero based on the ON output of the idle switch 37. And the rotational speed and the vehicle speed of the drive wheel 10 are detected based on the output of the wheel speed sensor 38. An inverter 6 and the like are connected to the output interface of the power management control computer 200 via the MG-ECU 8.

  The engine control computer 100 and the power management control computer 200 are based on signals input from the various sensors and switches described above, and drive control (fuel injection control) of the injector 18 and ignition timing control (ignition timing control) of the spark plug 16. ), A control program for executing various controls of the engine 1 including the drive control (throttle control) of the throttle motor 14 of the throttle valve 13 and the air-fuel ratio feedback control is provided, and the following “cooperative control” is executed. Equipped with a control program.

  In this embodiment, the elements connected to the input interface and the output interface of the engine control computer 100 and the power management control computer 200 are only those related to the features of the present invention.

  The engine control computer 100 operates the engine 1 such as the engine speed recognized from the output signal of the crank position sensor 36 and the accelerator pedal depression amount of the driver (accelerator opening read from the output signal of the accelerator opening sensor 35). Accordingly, the throttle opening is feedback-controlled so that the optimum amount of intake air in the cylinder can be obtained.

  Further, as throttle control performed by the engine control computer 100, a target intake air amount (including a load correction amount and the like) is calculated using an appropriate calculation model, map, and the like based on the engine rotation speed and the accelerator opening. The target intake air amount is converted into a target throttle opening ([flow rate → opening]), and the target throttle opening is converted into a throttle command voltage ([opening → voltage]). Based on the command voltage (target voltage) and the output voltage of the throttle opening sensor 33, the drive duty ratio of the throttle motor 14 is controlled so that the actual throttle opening matches the target throttle opening. As described above, the throttle control is feedback-controlled based on the difference between the target throttle opening and the actual throttle opening.

  Further, the engine control computer 100 executes idle rotation speed control (ISC: Idle Speed Control). This ISC control is executed when the engine 1 is idling, and the opening of the throttle valve 13 is adjusted so that the actual engine speed matches the target idle speed, and the intake air amount in the cylinder is fed back. Control. The actual idle speed (engine speed) is calculated from the output signal of the crank position sensor 36.

  Next, processing at the time of vehicle deceleration in the present invention will be described.

  If the high load operation of the engine 1 is continued, the temperature of the engine 1 becomes high and the atmospheric temperature in the engine compartment becomes high, so that the intake air temperature also becomes high. If the fuel cut is executed for a long time in such a situation that the temperature of the injector 18 is likely to rise, the fuel inside the injector 18 is likely to vaporize. By the way, as a vehicle usage pattern in which the situation is as described above, for example, a mode in which a hill is continuously climbed while towing a heavy object and then the hill is lowered is assumed.

  Considering such circumstances, in this embodiment, first, when the fuel cut is executed for a long time in a state where the temperature of the injector 18 is likely to rise, the opening of the throttle valve 13 is set to be larger than the normal time, The nozzle of the injector 18 is cooled by the intake air passing through the throttle valve 13.

  However, if this is done, the deceleration effect due to the engine brake is impaired, and it is predicted that a feeling of idling will occur. Therefore, in cooperation with the throttle control, the motor generator MG2 is regenerated to generate negative torque. Thus, a braking force (deceleration force) is applied to the vehicle.

  By the way, when the fuel cut is performed during the steady operation of the engine 1, the target throttle opening is set to “ISC learning value (throttle opening)” for securing the intake air amount for avoiding engine stall. “Feedback value” and “correction value eqfc” are added and set. The target throttle opening at this time is referred to as a “normal target throttle opening”.

  The ISC learning value is acquired by a learning process that is periodically performed, and stored in a backup RAM of the engine control computer 100, for example. The correction value eqfc is set to suppress oil consumption in the cylinder 1a of the engine 1. In general, at the time of fuel cut, the oil consumption tends to increase, for example, oil is easily drawn into the cylinder 1a from the cylinder head side and the crankcase side as the downstream side of the throttle valve 13 becomes negative pressure.

  In order to suppress such oil consumption, it is desirable to appropriately increase the throttle opening so that the pressure downstream of the throttle valve 13 is less likely to be negative. Considering this point, the correction value eqfc is grasped by appropriate experiments and simulations and set empirically.

  Specifically, with reference to a flowchart shown in FIG. 3, control in which throttle control during deceleration of engine 1 and deceleration control of vehicle speed by motor generator MG2 are coordinated will be described in detail.

  The flowchart of FIG. 3 is started every predetermined cycle (several milliseconds) after the engine 1 is started, for example. First, in step S1, it is determined whether or not the engine coolant temperature Te is equal to or higher than a predetermined threshold value X1. Here, it is examined whether or not the coolant temperature of the engine 1 has risen to near the upper limit value of the adjustment range.

  The engine coolant temperature Te is recognized based on the output from the engine temperature sensor 32. The threshold value X1 is empirically set by grasping the coolant temperature after the engine 1 is operated at a high load by an embodiment or a simulation.

  Here, if Te <X1, a negative determination is made in step S1, and this flowchart is terminated. On the other hand, if Te ≧ X1, an affirmative determination is made in step S1, and the process proceeds to the subsequent step S2.

  In this step S2, it is determined whether or not the intake air temperature Ti is equal to or higher than a predetermined threshold value X2. The intake air temperature Ti is recognized based on the output from the intake air temperature sensor 31. The threshold value X2 is empirically set by grasping the intake air temperature after the engine 1 is operated at a high load by an appropriate experiment or simulation.

  Here, if Ti <X2, a negative determination is made in step S2, and this flowchart ends. On the other hand, if Ti ≧ X2, an affirmative determination is made in step S2, and the process proceeds to the subsequent step S3.

  In step S3, the high temperature environment flag is set to “1”. That is, when both the determinations in steps S1 and S2 are affirmative, it is determined that the vicinity of the injector 18 is hot and the temperature of the injector 18 is likely to rise.

  In subsequent step S4, it is determined whether or not fuel cut has been started. If the fuel cut has not been started, a negative determination is made in step S4, and this flowchart is terminated. On the other hand, when the fuel cut has been started, an affirmative determination is made in step S4, and the process proceeds to the subsequent step S5.

  In step S5, throttle control suitable for the high temperature condition is executed. In this throttle control, the target throttle opening is set to be larger than the target throttle opening at the steady state. The target throttle opening at this time is referred to as a “target throttle opening for a high temperature situation” and can be, for example, fully opened.

  However, as the target throttle opening degree for the high temperature situation, the “ISC feedback value” and the “ISC learning value (throttle opening degree)” for securing the intake air amount for avoiding the stall of the engine 1 and “ The correction value eqfc ”and the“ second correction value eqfc2 ”can be added and set. The second correction value eqfc2 is a value of the throttle opening corresponding to the amount of increase in the intake air amount necessary to enhance the cooling action of the injector 18, and is determined in advance through appropriate experiments or simulations and set empirically. Is done.

  Thereafter, in the subsequent step S6, the power management control computer 200 is instructed to execute control for decelerating the vehicle speed by causing the motor generator MG2 to regenerate to generate negative torque.

  Further, in the subsequent step S7, it is determined whether or not the fuel cut is continued.

  If the fuel cut is continued, an affirmative determination is made in step S7, and the process returns to step S5. When the fuel cut ends, a negative determination is made in step S7, and this flowchart ends.

  Next, referring to the timing chart shown in FIG. 4, the state of the cooperative control in the above-described high temperature state will be described.

  For example, as shown in FIG. 4A, after the high temperature environment flag is set to “1” at time t1, as shown in FIG. 4B, the accelerator opening starts to close at time t2, and at time t3. If the idle switch 37 is turned on, as shown in FIGS. 4C and 4D, the idle flag and the fuel cut flag are set to “1”, and the fuel cut is started.

  By the way, the throttle opening is closed following the closing operation of the accelerator opening as shown in FIG. 4 (e). However, as the fuel cut flag is set to “1”, the throttle opening is reduced. The opening degree is set to a throttle opening degree for a high temperature situation (see a solid line, for example, a fully open state). In FIG. 4 (e), the alternate long and short dash line indicates the throttle opening at the steady state.

  As a result, the nozzle of the injector 18 is cooled by the large amount of intake air that flows in through the throttle valve 13, so that fuel vaporization inside the injector 18 is suppressed or prevented. However, the deceleration action by the engine brake is lost.

  At the same time, since the motor generator MG2 is regeneratively operated, negative torque is generated from the motor generator MG2, as shown in FIG. 4 (f), but the torque at that time gradually increases to the negative side. To be controlled. As a result, braking force (deceleration force) is gradually applied to the vehicle, so that a feeling of deceleration can be obtained without causing a deceleration shock.

  Thereafter, as shown in FIG. 4B, when the depression operation amount of the accelerator pedal (not shown) is started and the depression operation amount becomes zero or more at time t4 and the idle switch 37 is turned off. 4 (c) and 4 (d), the idle flag and the fuel cut flag are reset to “0”, the fuel cut is terminated, and the fuel injection from the injector 18 is restarted. When returning from the fuel cut, fuel vaporization inside the injector 18 is suppressed or prevented by the above-described cooling process of the intake air, so that the combustion of the engine 1 is stably performed.

  In such an embodiment, the engine control computer 100 and the power management control computer 200 correspond to a “control device” according to the present invention. However, when a single integrated computer is used, this integrated computer corresponds to the control device according to the present invention.

  Further, the engine control computer 100 and the power management control computer 200 realize each item (function) described in the claims. That is, steps S1 to S3 in FIG. 3 correspond to the “situation determination unit” according to claim 5, and step S4 in FIG. 3 corresponds to the “fuel cut determination unit” according to claim 5, and FIG. Step S <b> 5 corresponds to a “handling unit” according to claim 5. Further, steps S5 and S6 in FIG. 3 correspond to a “handling unit” described in claim 7.

  As described above, in the embodiment to which the present invention is applied, in the hybrid vehicle, when the fuel cut is executed in a situation where the temperature of the engine 1 and the atmospheric temperature in the engine compartment are high, the vehicle is decelerated. It is possible to suppress or prevent the injector 18 from overheating without sacrificing the action.

  As a result, fuel vaporization inside the injector 18 can be suppressed or prevented, so that it is possible to stabilize combustion at the time of return from the fuel cut, thereby improving drivability. You can contribute.

  In addition, this invention is not limited only to the said embodiment, It can change suitably in the range equivalent to the claim and the said range.

  (1) In the above embodiment, as an application target of the present invention, a so-called “split method” hybrid vehicle is taken as an example, but the present invention is not limited to this, and for example, “series method” or “ A “parallel type” hybrid vehicle is possible.

  (2) In the above embodiment, a hybrid vehicle including two motor generators MG1 and MG2 is given as an example of an application target of the present invention. However, the present invention is not limited to this, for example, one Alternatively, a hybrid vehicle including three or more motor generators can be provided.

  For example, a hybrid vehicle including three motor generators may have a configuration in which a motor generator for driving a rear wheel axle is provided in addition to the motor generators MG1 and MG2 shown in the above embodiment.

  (3) In the above embodiment, the example in which the cooperative control is immediately executed when the fuel cut is started when the high temperature environment flag is set to “1” is described. Is not limited to this.

  For example, when the high temperature environment flag is set to “1”, it is possible to execute the cooperative control when the fuel cut is continued for a predetermined time or more.

  Specifically, the cooperative control in the present invention will be described in detail with reference to the flowchart shown in FIG.

  The flowchart of FIG. 5 is started every predetermined cycle (several milliseconds) after the engine 1 is started, for example. First, in step S11, it is determined whether or not the engine coolant temperature Te is equal to or higher than a predetermined threshold value X1. Here, it is examined whether or not the coolant temperature of the engine 1 has risen to near the upper limit value of the adjustment range.

  The engine coolant temperature Te is recognized based on the output from the engine temperature sensor 32. The threshold value X1 is empirically set by grasping the coolant temperature after the engine 1 is operated at a high load by an embodiment or a simulation.

  Here, if Te <X1, a negative determination is made in step S11, and this flowchart is terminated. On the other hand, if Te ≧ X1, an affirmative determination is made in step S11, and the process proceeds to the subsequent step S12.

  In step S12, it is determined whether the intake air temperature Ti is equal to or higher than a predetermined threshold value X2. The intake air temperature Ti is recognized based on the output from the intake air temperature sensor 31. The threshold value X2 is empirically set by grasping the intake air temperature after the engine 1 is operated at a high load by an appropriate experiment or simulation.

  Here, if Ti <X2, a negative determination is made in step S12, and this flowchart is terminated. On the other hand, if Ti ≧ X2, an affirmative determination is made in step S12, and the process proceeds to the subsequent step S13.

  In step S13, the high temperature environment flag is set to “1”. That is, when both the determinations in steps S11 and S12 are affirmative, it is determined that the vicinity of the injector 18 is hot and the temperature of the ink jet 18 is likely to rise.

  In a succeeding step S14, it is determined whether or not the fuel cut has been started. If the fuel cut has not been started, a negative determination is made in step S14, and this flowchart is terminated. On the other hand, when the fuel cut has been started, an affirmative determination is made in step S14, and the process proceeds to the subsequent step S15.

  In step S15, it is determined whether or not the fuel cut execution time tfc has exceeded a predetermined threshold value Y.

  That is, here, it is checked whether the injector 18 has received heat necessary for raising the temperature to a temperature at which the fuel inside thereof vaporizes. The threshold value Y is set empirically by grasping the relationship between the duration of fuel cut after high-load operation of the engine 1 and the temperature rise of the injector 18 through an embodiment or simulation.

  If tfc <Y, a negative determination is made in step S15, and this flowchart is terminated. On the other hand, if tfc ≧ Y, an affirmative determination is made in step S15, and the flow proceeds to the subsequent step S16.

  In step S16, throttle control suitable for the high temperature condition is executed. In this throttle control, the target throttle opening is set to be larger than the target throttle opening at the steady state. The target throttle opening at this time is referred to as a “target throttle opening for a high temperature situation” and can be, for example, fully opened.

  However, as the target throttle opening degree for the high temperature situation, the “ISC feedback value” and the “ISC learning value (throttle opening degree)” for securing the intake air amount for avoiding the stall of the engine 1 and “ The correction value eqfc ”and the“ second correction value eqfc2 ”can be added and set. The second correction value eqfc2 is a value of the throttle opening corresponding to the amount of increase in the intake air amount necessary to enhance the cooling action of the injector 18, and is determined in advance through appropriate experiments or simulations and set empirically. Is done.

  Thereafter, in subsequent step S17, the power management control computer 200 is instructed to execute control for decelerating the vehicle speed by causing the motor generator MG2 to perform a regenerative operation to generate negative torque.

  Further, in the subsequent step S18, it is determined whether or not the fuel cut is continued.

  Here, when the fuel cut is continued, an affirmative determination is made in step S18, and the process returns to step S16. When the fuel cut ends, a negative determination is made in step S17, and this flowchart ends.

  In this embodiment, it is determined based on the fuel cut execution time whether or not there is a high possibility that the fuel will actually vaporize inside the injector 18 as the fuel cut is executed in a high temperature condition. The cooperative control is executed when “the fuel is likely to vaporize”. In this way, when the conditions for permitting execution of the cooperative control are strict, it is possible to avoid waste, such as avoiding the execution even though the cooperative control does not need to be executed. become.

  In this embodiment, steps S11 to S13 in FIG. 5 correspond to the “situation determination unit” according to claim 6, and step S14 in FIG. 5 corresponds to the “fuel cut determination unit” according to claim 6. Step S15 in FIG. 5 corresponds to an “execution time determination unit” according to claim 6, and step S16 in FIG. 5 corresponds to a “coping unit” in claim 6. Further, steps S16 and S17 in FIG. 5 correspond to a “handling unit” according to claim 7.

  (4) In the above-described embodiment, an example in which the motor generator MG2 is used as the braking force applying element described in the claims is given, but the present invention is not limited to this.

  For example, although not shown, when a hybrid vehicle is equipped with an electronic control braking system (ECB), it is possible to apply braking force to the vehicle using this ECB. It is. In this case, the ECB corresponds to the braking force applying element described in the claims.

  Specifically, although not shown, the vehicle is gradually moved with the braking force obtained by operating the ECB for the process of step S6 of the flowchart shown in FIG. 3 or the process of step S17 of the flowchart shown in FIG. It is possible to replace it with a form of slowing down.

  The present invention is suitably used as a control device for a hybrid vehicle in which an engine and a motor are used as a drive source for generating a driving force for traveling, and a throttle valve and an injector are installed in an intake passage of the engine. be able to.

1 Engine MG1 Motor generator MG2 Motor generator
11 Intake passage
11a Intake port
13 Throttle valve
16 Spark plug
17 Igniter
18 Injector
20 Crankshaft
30 Air flow meter
31 Intake air temperature sensor
32 Engine temperature sensor
33 Throttle opening sensor
35 Accelerator position sensor
36 Crank position sensor
37 Idle switch 100 Engine control computer 200 Power management control computer

Claims (7)

A control device for a hybrid vehicle having a configuration in which an engine and a motor are used as a drive source for generating a driving force for traveling, and a throttle valve and an injector are installed in an intake passage of the engine,
The hybrid vehicle control device, wherein when performing fuel cut in a state where the temperature of the injector is likely to rise, the throttle valve opening is made larger than normal. In the hybrid vehicle control device according to claim 1,
The situation where the temperature of the injector is likely to rise is a case where the coolant temperature of the engine is equal to or higher than a predetermined value and the intake air temperature of the engine is equal to or higher than a predetermined value. apparatus. The hybrid vehicle control device according to claim 1 or 2,
In addition to the throttle valve opening control, a control device for a hybrid vehicle that controls a braking force generating element for applying a braking force to the vehicle. In the hybrid vehicle control device according to claim 3,
The control device for a hybrid vehicle, wherein the braking force generation element is the motor, and generates negative torque by causing the motor to regenerate when the braking force is required. The control device for a hybrid vehicle according to claim 1 comprises:
A situation determination unit that determines that the injector is likely to rise in temperature when the engine coolant temperature is equal to or higher than a predetermined value and the engine intake air temperature is equal to or higher than a predetermined value;
A fuel cut determination unit for determining whether or not a fuel cut is being executed;
When the situation determination unit determines that the temperature is likely to rise, and the fuel cut determination unit determines that fuel cut is being performed, the target throttle opening is set to a steady target throttle opening. And a coping unit that operates the throttle valve so as to make the actual throttle opening coincide with the set target throttle opening. The control device for a hybrid vehicle according to claim 1 comprises:
A situation determination unit that determines that the injector is likely to rise in temperature when the engine coolant temperature is equal to or higher than a predetermined value and the engine intake air temperature is equal to or higher than a predetermined value;
A fuel cut determination unit for determining whether or not a fuel cut is being executed;
An execution time determination unit that determines whether or not the execution time of the fuel cut has exceeded a predetermined value;
The situation determination unit determines that the temperature is easy to rise, the fuel cut determination unit determines that fuel cut is being executed, and the execution time determination unit determines that a predetermined value or more has elapsed. ”Is set, the target throttle opening is set larger than the steady target throttle opening, and the throttle valve is operated so that the actual throttle opening coincides with the set target throttle opening. The control apparatus of the hybrid vehicle characterized by including a part. In the hybrid vehicle control device according to claim 5 or 6,
The coping unit generates a negative torque by causing the motor to perform a regenerative operation in addition to the setting of the target throttle opening degree.

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