JP2001280185A - Start control device for internal combustion engine and vehicle having it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve exhaust gas properties in starting of an internal combustion engine as well as to improve startability of the internal combustion engine. SOLUTION: In starting of an engine 10, a control unit 70 determines a cylinder 101 for injecting fuel on the basis of a cylinder judged result based on fuel pressure detected by a fuel pressure sensor 50, a crank angle signal position from a crank position sensor 54, and a cylinder discriminating signal from a cam position sensor 52. The control unit 70 injects high-pressure fuel to the determined cylinder 101 through an injector 12. When fuel injection is performed in the latter period of a compression stroke of the cylinder 101, the engine 10 can be started in first ignition timing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a start control technique for an internal combustion engine, and more particularly to a start control technique suitable for a direct injection type internal combustion engine in which fuel is directly injected into a cylinder.

[0002]

2. Description of the Related Art In order to more accurately control the combustion state of an internal combustion engine according to the operating state of a vehicle, a direct injection type internal combustion engine that injects fuel directly into a cylinder has been put to practical use. In a direct injection type internal combustion engine, fuel efficiency of the internal combustion engine is generally improved by executing stratified combustion in a low load region of the internal combustion engine. This stratified combustion is realized by executing fuel injection in the compression stroke. In injecting fuel, the fuel is injected at a high fuel pressure (fuel pressure) so as to overcome the increase in the cylinder pressure in the compression stroke. Is required. However, this high fuel pressure is generally generated by a mechanical pump (high-pressure pump) driven by the operating internal combustion engine, and is generated over time when the operation of the internal combustion engine is stopped. The fuel pressure may decrease.

[0003] Therefore, even in such a direct injection type internal combustion engine, at the time of starting, fuel having a low fuel pressure is injected into a cylinder during an intake stroke in the same manner as in a conventional internal combustion engine.
The problem of fuel pressure shortage at the time of starting the internal combustion engine is avoided (Japanese Patent Application Laid-Open No. 8-313401). Alternatively, the problem of fuel pressure shortage at the start of the internal combustion engine is avoided by executing ignition processing after injecting fuel into the cylinder many times to atomize the fuel sufficiently (Japanese Patent Laid-Open No. 11-27038).
No. 7).

[0004]

However, when fuel is injected in the intake stroke at the start of the internal combustion engine while employing the direct injection type internal combustion engine, ignition is performed only after the compression stroke. I could not expect a quick start of the engine. On the other hand, if an attempt is made to inject fuel into a cylinder whose ignition timing is to be reached immediately after the start of cranking (a cylinder in the latter half of the compression stroke), the fuel pressure may be insufficient, and the start is not necessarily accelerated. In particular, in a vehicle having an idling stop function for stopping and restarting the idling operation of the internal combustion engine according to the vehicle state, a delay in starting the internal combustion engine prevents smooth running of the vehicle again.

[0005] The present invention has been made to solve the above problem, and has as its object to improve the startability of an internal combustion engine. It is another object of the present invention to improve exhaust gas characteristics at the start of an internal combustion engine.

[0006]

In order to solve the above-mentioned problems, a first aspect of the present invention is to directly supply fuel pressurized by a booster using an internal combustion engine as a power source into a cylinder. Provided is a start-time fuel injection control device for an internal combustion engine including a fuel injection valve that injects fuel. A fuel injection device according to a first aspect of the present invention, wherein a fuel pressure detection unit detects a pressure of fuel that can be injected by the fuel injection valve at the time of starting,
Fuel injection timing determining means for determining the timing of fuel injection in a combustion cycle according to the detected fuel pressure,
Injection control means for injecting fuel via the fuel injection valve at the determined fuel injection timing.

A starting fuel injection control device according to a first aspect of the present invention determines a fuel injection timing in a combustion cycle in accordance with a detected fuel pressure, and operates a fuel injection valve at the determined fuel injection timing. Since fuel is injected through the fuel injection device, fuel injection can be performed at an appropriate timing of the combustion cycle according to the fuel pressure even when the internal combustion engine is started.

In the fuel injection control device for starting an internal combustion engine according to a first aspect of the present invention, the internal combustion engine has a plurality of cylinders, and each of the cylinders is provided with the fuel injection valve. The fuel injection control device may further include a cylinder discriminating unit that discriminates a cylinder at the injection timing determined by the fuel injection timing determining unit from the plurality of cylinders. When the pressure of the fuel is equal to or higher than the first pressure, the fuel injection timing determining means can determine the compression stroke as the fuel injection timing. The fuel injection timing determining means may determine the intake stroke as the fuel injection timing when the pressure of the fuel is lower than the first pressure.

With this configuration, when the fuel pressure is equal to or higher than the first pressure, for example, 5 MPa, it is possible to execute the fuel injection at the first ignition timing, thereby improving the startability of the internal combustion engine. Can be done. When the fuel pressure is lower than the first pressure, the fuel injection can be performed at the next ignition timing, and the start timing of the internal combustion engine is advanced while surely supplying fuel to the cylinder during the intake stroke. be able to. Further, since fuel is injected into the cylinders in the compression stroke or the intake stroke, unburned gas is not discharged, and the exhaust gas characteristics can be improved.

[0010] In the start-time fuel injection control device according to the first aspect of the present invention, the fuel injection timing determining means may determine whether the fuel pressure is equal to or higher than a second pressure higher than the first pressure. The latter half of the compression stroke can be determined as the fuel injection timing. The fuel injection timing determining means may determine the first half of the compression stroke as the fuel injection timing when the pressure of the fuel is lower than the second pressure and higher than the first pressure.

With such a configuration, when the fuel pressure is equal to or higher than the second pressure, for example, 10 MPa, it is possible to execute the fuel injection in the latter half of the compression stroke when the ignition timing comes soon. Can be started quickly. Further, even when the fuel pressure is lower than the second pressure, the fuel injection can be executed in the early stage of the compression stroke closer to the ignition timing than the intake stroke, so that the startability of the internal combustion engine can be improved.

The starting fuel injection control device according to the first aspect of the present invention further includes an in-cylinder pressure detecting means for detecting the pressure in the cylinder, and a vehicle in which the request for starting the internal combustion engine requires the vehicle to start. Start request determining means for determining whether or not the start request is based on the start request, the injection control means,
When it is determined that the start request is not based on the vehicle start request, after the detected in-cylinder pressure becomes equal to or less than a predetermined value, the fuel injection to the determined cylinder is started. Is also good.

With this configuration, the first fuel injection and explosive combustion can be performed when the amount of air taken into the cylinder is reduced, so that the combustion pressure can be reduced. Vibration or the like accompanying the start of the internal combustion engine at the request of the vehicle can be suppressed.

According to a second aspect of the present invention, there is provided a fuel injection device having a plurality of cylinders, and in each of the cylinders, a fuel injection device for directly injecting fuel pressurized by a booster using an internal combustion engine as a power source into the cylinders. The present invention provides a start control device for an internal combustion engine. A start control device according to a second aspect of the present invention includes a fuel pressure detection unit that detects a pressure of fuel injected by the fuel injection device, and a cylinder that determines a compression stroke cylinder in a compression stroke among the plurality of cylinders. A first-injection cylinder determining unit that determines a first-injection cylinder that first injects fuel when the internal combustion engine is started, based on a determination result by the cylinder determination unit and the detected fuel pressure, Starting means for injecting fuel into the determined first-injection cylinder via the fuel injection device and performing ignition to start the internal combustion engine is provided.

According to the start control apparatus of the second aspect of the present invention, the first fuel injection at the start of the internal combustion engine is performed based on the determination result by the cylinder determination means and the detected fuel pressure. It is possible to determine the injection cylinder, inject fuel through the fuel injection device to the determined first injection cylinder, and execute ignition. Therefore, even when the internal combustion engine is started, fuel can be injected in the compression stroke and explosive combustion by ignition can be performed, and the start timing of the internal combustion engine can be advanced. The respective strokes in the combustion cycle of the internal combustion engine are associated with each other. For example, in determining the compression stroke cylinder, it is possible to directly determine the compression stroke cylinder or to determine the intake stroke cylinder.

In the start control apparatus according to a second aspect of the present invention, the first injection cylinder determining means determines that the detected fuel pressure is equal to or higher than the first pressure by the cylinder determining means. Further, the compression stroke cylinder can be determined as the first injection cylinder. When the detected pressure of the fuel is lower than the first pressure and equal to or higher than a second pressure lower than the first pressure, the next compression stroke in which the compression stroke next to the compression stroke cylinder is performed The cylinder can be determined as the first injection cylinder. Further, when the detected fuel pressure is lower than the second pressure, the next compression stroke cylinder that reaches the next compression stroke after the next compression stroke cylinder can be determined as the first injection cylinder.

By providing such a configuration, it becomes possible to execute the fuel injection to the cylinder whose ignition timing is the earliest according to the fuel pressure, and the start timing of the internal combustion engine can be advanced. The first pressure in the second embodiment is, for example, 5 MPa, and the second pressure is 10 MPa.

Also in the start control device according to the second aspect of the present invention, in order to reduce the vibration at the time of starting the internal combustion engine, similarly to the start-time fuel injection control device according to the first aspect, the start control device in the cylinder is provided. The timing of fuel injection into the first injection cylinder may be delayed until the pressure becomes equal to or less than the predetermined value.

According to a third aspect of the present invention, there is provided a fuel injection device having a plurality of cylinders, and in each of the cylinders, a fuel injection device for directly injecting fuel pressurized by a booster using an internal combustion engine as a power source into the cylinders. The present invention provides a starting control device for an internal combustion engine. A start control device according to a third aspect of the present invention includes a fuel pressure detection unit configured to detect a pressure of fuel injected by the fuel injection device, and a fuel pressure detection unit that detects a pressure in an initial stroke of a compression stroke or an exhaust stroke of the plurality of cylinders. Cylinder group identification means for identifying the cylinder group of the cylinder group; cylinder identification means for identifying a compression stroke cylinder in a compression stroke of the specific cylinder group after the specific cylinder group is identified; and the cylinder group identification means. First-injection cylinder determining means for determining a first-injection cylinder to inject fuel first when the internal combustion engine is started, based on the identification result by the determination result by the cylinder determination means, and the detected fuel pressure, Starting means for injecting fuel into the determined first-injection cylinder via the fuel injection device and performing ignition to start the internal combustion engine is provided.

According to the start control apparatus of the third aspect of the present invention, it is possible to identify a specific group of cylinders in the initial stroke of the compression stroke or the exhaust stroke among the plurality of cylinders. Even before this, fuel can be preliminarily injected into the cylinders that undergo the compression stroke at the time of cylinder determination. This makes it possible to supply fuel into the cylinder in accordance with the first ignition timing even if fuel injection is impossible at the time of cylinder discrimination from the aspect of fuel pressure, thereby improving the startability of the internal combustion engine. be able to.

In the start control apparatus according to a third aspect of the present invention, the first injection cylinder determining means determines that the specific cylinder group has been identified but the compression stroke cylinder has not been determined, and the detected cylinder has not been detected. When the fuel pressure is equal to or higher than the first pressure, the control unit waits for the determination of the compression stroke cylinder of the cylinder by the cylinder determination unit. When the compression stroke cylinder is determined, the first injection of the compression stroke cylinder is performed. The cylinder can be determined. If the detected pressure of the fuel is lower than the first pressure and equal to or higher than a second pressure lower than the first pressure, the identified specific cylinder group is determined as a first injection cylinder. can do. Further, when the detected pressure of the fuel is lower than the second pressure, a cylinder group that enters a compression stroke or an exhaust stroke next to the specific cylinder group can be determined as the first injection cylinder.

With this configuration, when the fuel pressure is equal to or higher than the first pressure, for example, 10 MPa, the fuel injection in the compression stroke is executed after the completion of the cylinder discrimination, and the ignition is performed at the first ignition timing. can do. When the fuel pressure is lower than the first pressure and higher than the second pressure, for example, 5 MPa, the cylinder which is first in the compression stroke after the cylinder discrimination, that is, the cylinder which first reaches the ignition timing,
Fuel can be supplied into the cylinder when fuel can be supplied from the aspect of fuel pressure, and the start timing of the internal combustion engine can be advanced. Further, when the fuel pressure is lower than the second pressure, the cylinder which reaches the second compression stroke after the cylinder discrimination, that is, the cylinder which reaches the second ignition timing, is set to a timing at which fuel can be supplied from the side of the fuel pressure. Fuel can be supplied into the cylinder, and the internal combustion engine can be started as early as possible.

According to a fourth aspect of the present invention, there is provided a vehicle including the fuel injection control device according to the first aspect of the present invention. Further, a fifth aspect of the present invention provides a vehicle including the start control device according to the second or third aspect of the present invention. When such a configuration is provided, the vehicle can be started quickly.

The vehicle according to the fourth and fifth aspects of the present invention further comprises an idling control means for stopping the idling operation of the internal combustion engine according to the state of the vehicle and resuming the operation of the internal combustion engine having stopped the idling operation. When the operation of the internal combustion engine is restarted, supply of fuel to the internal combustion engine may be controlled by the fuel injection control device or the start control device. With such a configuration, the vehicle can be quickly restarted after the idling operation is stopped.

According to a sixth aspect of the present invention, there is provided a fuel injection device having a plurality of cylinders, and in each of the cylinders, a fuel injection device for directly injecting fuel pressurized by a booster using an internal combustion engine as a power source into the cylinders. To provide a starting control method for an internal combustion engine. A method according to a sixth aspect of the present invention includes detecting a pressure of fuel that can be injected by the fuel injection device, and determining that a specific group of cylinders among the plurality of cylinders is in an initial stroke of a compression stroke or an exhaust stroke. Detecting a cylinder group identification signal indicating the cylinder group identification signal for identifying a compression stroke cylinder in a compression stroke of the specific cylinder group, and detecting the cylinder group identification signal and the cylinder group identification signal. Based on the cylinder discrimination signal detected later and the detected fuel pressure, the first injection cylinder that first injects fuel at the start of the internal combustion engine is determined, and before the first injection cylinder reaches ignition timing, When the ignition cylinder is determined based on the cylinder group identification signal and the cylinder determination signal detected after detecting the cylinder group identification signal, and fuel is injected through the fuel injection device to the determined first injection cylinder. The running ignited against ignition cylinders, characterized in that to start the internal combustion engine.

According to the method of the sixth aspect of the present invention,
Since a specific group of cylinders in the compression stroke or the initial stroke of the exhaust stroke among a plurality of cylinders can be identified, even before the completion of the cylinder discrimination, a cylinder that enters the compression stroke during the cylinder discrimination is preliminarily prepared. Fuel can be injected. This makes it possible to supply fuel into the cylinder in accordance with the first ignition timing even if fuel injection is not possible at the time of cylinder discrimination from the aspect of fuel pressure, thereby accelerating the start timing of the internal combustion engine. Can be.

It should be noted that the present invention can be specified as the method for the first and second aspects of the present invention in the same manner, and the same operation and effect as those of the first and second aspects of the present invention, respectively, can be obtained. Can play.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An internal combustion engine start control device according to the present invention will be described below based on an embodiment with reference to the drawings.

Referring to FIGS. 1 and 2, a schematic configuration of a vehicle in which the idling stop control device including the start control device according to the present embodiment can be used will be described. FIG. 1 is a block diagram showing a schematic configuration of a vehicle to which the first embodiment is applied. FIG. 2 is an explanatory diagram showing a schematic configuration around the engine.

The vehicle has an engine (internal combustion engine) 10 as a power source, a torque converter 20 for amplifying the output torque of the engine 10, and a speed reduction ratio between a maximum reduction ratio and a minimum reduction ratio which can be automatically changed in steps. Automatic stepped transmission (A
T) 22. The engine 10 is connected to a power input shaft of a torque converter 20 via a crankshaft (output shaft) 11, and a power output shaft of the torque converter 20 is connected to a power input shaft of the AT 22.
The power output shaft of the AT 22 is connected to the drive shaft 24. The drive shaft 24 is connected to wheels 27 via a differential gear (including a final gear) 25 and an axle 26.

The engine 10 is a direct-injection gasoline engine in which fuel (for example, gasoline fuel) is directly injected into a cylinder 101 as shown in FIG. The cylinder head 102 of the engine 10 has a high-pressure injector 1 for injecting gasoline fuel into the cylinder 101.
2. It has an ignition plug 13 for igniting a mixture formed by gasoline injected into the cylinder 101 and the sucked air. The high-pressure injector 12 has a high-pressure fuel pump 19 driven by the engine 10.
The high-pressure gasoline fuel pressurized by the above is supplied via the delivery pipe 18, and when the high-pressure injector 12 opens based on an injection signal from the control unit 70, the gasoline fuel is sprayed into the cylinder 101.
The delivery pipe 18 is provided with a fuel pressure sensor 50 that detects the pressure (fuel pressure) of the fuel in the delivery pipe, that is, the fuel pressure Pf that can be injected from the high-pressure injector 12. A high voltage is supplied to the ignition plug 13 from the igniter 14 based on an ignition signal from the control unit 70.
The ignition signal is transmitted from the control unit 70 to the igniter 14 after the cylinder discrimination is completed.

The cylinder head 10 of the engine 10
Reference numeral 2 denotes an intake port 103 for introducing intake air into the cylinder 101, an exhaust port 104 for discharging combustion gas out of the cylinder 101, an intake valve 110 for communicating or shutting off the intake port 103 and the cylinder 101, and an exhaust port 10.
An exhaust valve 111 for communicating or shutting off the cylinder 4 and the cylinder 101 is provided. An intake pipe 120 for introducing external air is connected to the intake port 103. Surge tank 1 having intake pressure sensor 51 in intake pipe 120
21, a throttle valve 122 for adjusting the amount of intake air into the cylinder 101 is provided. Intake valve 11
0 and the exhaust valve 111 are opened and closed at a predetermined timing by a cam 113 provided on a cam shaft 112. The intake valve 110 is provided with a variable valve timing mechanism that continuously and variably changes the valve opening / closing timing from the most retarded position to the most advanced position. A cam position sensor 52 that outputs a cylinder discrimination signal for cylinder discrimination is arranged near the camshaft 112.

The cylinder block 105 of the engine 10 is provided with a coolant temperature sensor 53 for detecting the temperature of a coolant for cooling the engine 10. The crankshaft 11 is provided with a crank position sensor 54 for detecting a crank position of the crankshaft 11 and a crank angular velocity. Crank position sensor 5
Reference numeral 4 denotes a crankshaft timing pulley 541 having a signal tooth including a missing tooth portion for detecting a top dead center (TDC) on the outer peripheral portion, and 30 ° detecting passage of the signal tooth.
An MPU-type electromagnetic pickup 542 that outputs a crank rotation signal for each CA (crank angle) is provided.

Around the engine 10, auxiliary equipment 30 such as a water pump, an air conditioner compressor, and a power steering pump, and an auxiliary equipment driving motor (electric motor) for driving the auxiliary equipment 30 when the engine is stopped by idling stop processing. ) 31 are arranged. Power input shaft of each accessory 30, crankshaft 1 of engine 10
Pulleys 160 and 161 are mounted on one end of the pulley 1, respectively. A transmission belt 16 for starting the engine 10 by the accessory drive motor 31 is mounted on the pulley 161 of the engine 10 and the pulley 162 of the accessory drive motor 31. The pulley ratio between the pulley 161 and the pulley 162 is generally about 1: 2 to 1: 3. Each pulley 1
A transmission belt 17 is mounted on 60 and 161, and the output of the engine 10 is transmitted through the transmission belt 17 to the auxiliary machine 3.
0, and the output of the accessory driving motor 31 is transmitted to the power input shaft of the accessory 30 via the transmission belt 16 and the transmission belt 17. The transmission belts 16 and 17 have a so-called V-shaped cross section having a trapezoidal shape.
A belt or a so-called V-rib belt, which is thinner and wider than a V-belt and has a plurality of V-shaped grooves formed along its rotation direction, is used.
A material whose absorption characteristics such as shock and vibration change depending on temperature is used.

A wet multi-plate electromagnetic clutch 15 is interposed between the crankshaft 11 and the pulley 161. The electromagnetic clutch 15 includes a clutch plate 151 and a flywheel 152, and may be provided separately from the pulley 161 as shown in FIG. 1 or may be built in the pulley 161. The electromagnetic clutch 15 realizes disconnection and connection of power transmission between the crankshaft 11 and the transmission belt 16. The electromagnetic clutch 15 has a built-in damper (not shown) for reducing shock and vibration generated at the time of engagement.

When the vehicle is running, or when the vehicle is stopped while the engine 10 is operating, the electromagnetic clutch 1
5, the driving force of the crankshaft 11 is transmitted to the transmission belt 17, so that the accessory 30 is driven by the engine 10. On the other hand, when the operation of the engine 10 is stopped by the idling stop process, the electromagnetic clutch 15
Is released, the crankshaft 11 and the pulley 161 are mechanically separated, and the accessory 30 is driven by the accessory driving motor 31 via the transmission belt 16 and the pulley 161. At this time, the crankshaft 11 is
61 and the transmission belts 16 and 17 are mechanically separated from each other,
Need not be driven, and the load on the accessory drive motor 31 is reduced.

The accessory drive motor 31 is a three-phase motor having a three-phase coil on the stator side, and drives the drive power source for driving the crankshaft 11 and the accessory 30 when the engine 10 is restarted. In addition to functioning as a driving force source, it also functions as an alternator that is driven by the engine 10 to generate power when the engine 10 is operating. The drive of the accessory drive motor 31 is controlled by the inverter 200 based on a drive signal from the control unit 70. Inverter 200 includes high voltage battery 210 and DC /
Connected to DC converter 220. The high-voltage battery 210 is used exclusively as a power supply for driving the accessory drive motor 31, and stores the generated power when the accessory drive motor 31 functions as an alternator. The DC / DC converter 220 is connected to the control unit 7
0, and charges the battery 230 by decreasing the voltage of the high-voltage battery 210 or the voltage of the electric power generated by the auxiliary drive motor 31. Battery 230
Is used as a power source for driving a starting motor 41, an oil pump driving motor 45, and a control unit 70, which will be described later. In the present embodiment, a high-voltage battery 210 for driving the accessory driving motor 31, a control unit 70, and a battery 230 for driving the other motors 41 and 45 are provided. Only the battery 210 is provided, and the DC / DC converter 2 is used for the control unit 70 and the other motors 41 and 45.
The stepped-down power may be supplied via the power supply 20.

A starting ring gear 40 is connected to the crankshaft 11 between the engine 10 and the torque converter 20, and a gear of a starting motor 41 is connected to the starting ring gear 40. The starting motor 41 uses the battery 230 as a power source to drive and rotate the engine 10 only at the time of engine start with an operation of an ignition switch, that is, at the time of engine start except for engine restart with idling stop processing. The gear of the starting motor 41 is engaged with the ring gear 40 only at the time of engine start when the ignition position sensor 58 detects the switching of the ignition position from ON to STA, and is separated without joining with the ring gear 40 in normal times. Stored in the location. Also, as described above, when the engine 10 is restarted due to the idling stop process, the accessory drive motor 31 functions as a starter motor. That is, in the present embodiment, when the operation of the engine 10 is started (at the time of the first start), the starting motor 4
The start processing of the engine 10 is executed by 1, and the start processing of the engine 10 is executed by the accessory drive motor 31 when the engine 10 is restarted.

The starting of the engine 10 by the starting motor 41 is performed via the ring gear 40 accompanied by gear noise. If the starting is repeated frequently, the gear noise becomes a problem. Also, under idling stop control processing, gear wear due to frequent starting poses a problem. On the other hand, since the accessory drive motor 31 is coupled to the crankshaft 11 via the transmission belt 16, the crankshaft 11 can be driven (rotated) when the viscosity of the lubricating oil is high, such as in a cold state. In some cases, the engine 10 cannot be started. Therefore, the engine 10 is started by the starting motor 41 when the engine 10 is started, and the engine 10 is started by the accessory driving motor 31 when the engine 10 is restarted after the engine 10 has been started.

The torque converter 20 is a general fluid type torque converter, and amplifies the driving torque inputted to the input shaft and outputs it from the output shaft. Since the detailed configuration and operation of the torque converter are known, the description thereof is omitted. The automatic stepped transmission (AT) 22 is an automatic transmission having a planetary gear inside, and automatically changes a gear combination via a hydraulic actuator (not shown) according to a vehicle speed, an accelerator depression amount, and the like. To change the gear ratio. The output shaft of the AT 22 is connected to the drive shaft 24, and the driving force output from the output shaft of the AT 22 is transmitted to the wheels 27 via the drive shaft 24, the differential gear 25, and the axle 26. An oil pump drive motor 45 for maintaining the hydraulic pressure of the drive system even when the operation of the engine 10 is stopped is arranged near the AT 22. The oil pump drive motor 45 is operated using the battery 230 as a power supply.

Next, a control system of the vehicle according to this embodiment will be described with reference to FIG. FIG. 3 is an explanatory diagram illustrating a control system of the vehicle according to the first embodiment. Control unit 70
Is the idling stop ECU (electronic control unit)
700, engine ECU 710, and brake ECU
720 is provided. Each ECU 700, 710, 720
Is provided with a CPU, a ROM, a RAM, and the like. These ECUs are examples, and for example, an ECU that controls the AT 22 can be provided separately from the idling stop ECU 700.

The idling stop ECU 700 is a core ECU of the control unit 70 at the time of idling stop control. Idling stop ECU 7
00 is the engine ECU 710 and the brake ECU
720 via a signal line so that bidirectional communication is possible. The idling stop ECU 700 includes a fuel pressure sensor 50, an intake pressure sensor 51, a cam position sensor 5
2. Coolant temperature sensor 53, crank position sensor 54, motor rotation speed sensor 55 for detecting the rotation speed of auxiliary drive motor 31, vehicle speed sensor 5 for detecting the speed of the vehicle
6. A shift position sensor 57 for detecting a gear position, an accelerator opening sensor 58 for detecting a position of an accelerator pedal as an accelerator opening, a brake pedal sensor 59 for detecting whether a brake pedal is depressed, and a position of an ignition switch. The ignition position sensors 60 are connected via signal lines. Idling stop ECU 700
, An inverter 200, a starting motor 41, an electromagnetic clutch 15, a DC / DC converter 220, an oil pump driving motor 45, an AT 22, and an instrument panel 46 are connected.

The idling stop ECU 700 controls the rotation speed of the auxiliary drive motor 31 via the inverter 200, and executes the idling stop processing to control the engine 1
The drive of the auxiliary machine 30 is realized in a state where 0 is stopped. In addition, the engine 10 is switched from the idling stop state.
When the operation is restarted, the crankshaft 11 of the engine 10 is driven and rotated in place of the starting motor 41 to increase the engine speed to the starting speed. The idling stop ECU 700 controls an electromagnetic actuator (not shown) of the electromagnetic clutch 15 to realize engagement and release of the clutch plate 151 with the flywheel 152, and controls transmission and cutoff of power. The idling stop ECU 700 controls a hydraulic actuator (not shown) based on the detection data from the vehicle speed sensor 56, the shift position sensor 57, and the accelerator opening sensor 58, and changes the gear ratio at the optimum gear point. Idling stop ECU 700
A program for executing a start control process and a restart control process based on a vehicle side request according to the present embodiment is stored in the ROM.

The engine ECU 710 controls the fuel injection amount via the injector 12 based on a request from the idling stop ECU 700, and controls the operating state of the engine 10 by controlling the ignition timing via the igniter 14. When the vehicle is stopped by the idling stop process, the idling stop ECU 70
In response to the request from 0, the fuel injection to the engine 10 via the injector 12 is stopped to stop the operation of the engine 10.

The brake ECU 720 is connected to the brake actuator 47 and controls the brake actuator 47 so as to maintain the brake oil pressure until the driving force of the engine 10 sufficiently rises when restarting from the idling stop state. I do. Engine 10
The state where the driving force of the vehicle rises sufficiently means, for example, a state where the vehicle is held in a stopped state even when the brake pedal is released when the vehicle starts on a slope.

Next, a general operation of the vehicle having the above configuration will be described with reference to the configuration diagrams of FIGS. When the shift position is parking P or neutral N, the ignition position sensor 60 changes the ignition position from ON to the engine start position STA.
When the switch to is detected, the idling stop E
The CU 700 changes the gear of the starting motor 41 to the ring gear 40.
After that, the starting motor 41 is operated to rotate the crankshaft 11 to the engine rotation speed. At the same time, the idling stop ECU 700 requests the engine ECU 710 to start the engine 10. The engine ECU 710 includes the injector 12
A predetermined fuel is supplied into the cylinder 101 of the engine 10 via the igniter 14 and an engine start process for igniting the fuel supplied into the cylinder 101 via the igniter 14 and the ignition plug 13 is executed. In the present embodiment, control for changing the fuel injection cylinder in accordance with the fuel pressure Pf, that is, for changing the fuel injection timing, is performed as described later in the engine start processing.

When the operation of the engine is started, the gear of the starting motor 41 is retracted to a storage position separated from the ring gear 40. When the shift position is changed to drive D and the accelerator pedal is depressed, the vehicle starts. And the shift control of the AT 22 are executed.

In this embodiment, when the vehicle is temporarily stopped due to a traffic light stop or the like while the vehicle is running, the idling stop EC
U700 executes a so-called idling stop control process for stopping the operation of engine 10 under predetermined conditions. FIG. 4 shows the idling stop control process.
This will be described with reference to FIG. FIG. 4 is a state transition diagram showing a transition state of the control processing during the idling stop control processing.

When the ignition position sensor 47 is
Upon detecting the switching of the position from FF to ON, the idling stop ECU 700 selects a mode 0 indicating an engine stop state due to processing other than the idling stop processing. In this state, the display lamp on the instrument panel 46 that indicates that the idling stop process is being executed is turned off. When the ignition position sensor 47 turns on the ignition position
When the switch to A is detected, the operation of the engine 10 using the starting motor 14 is started as described above. The idling stop ECU 700 selects a mode 1 indicating a state in which the engine 10 is operating. In the mode 1 state, for example, the vehicle is in the vehicle running state described above, or in the vehicle stopped state while the engine 10 is operated. In the mode 1 state, the idling stop ECU 700 turns on the electromagnetic clutch 15 to connect the crankshaft 11 and the transmission belt 17. Therefore, accessory 30 is driven by the driving force of engine 10. The accessory driving motor 31 is connected to the transmission belt 16.
, And functions as an alternator, and runs idle when the high-voltage battery 210 is fully charged.

When the idling stop ECU 700 determines that the idling stop control processing condition is satisfied,
Mode 2 indicating a process for stopping the operation of the engine 10 is selected. As the idling stop control processing conditions, for example, the vehicle speed detected by the vehicle speed sensor 56 is 0, the depression of the brake pedal is detected by the brake pedal sensor 59, and the shift position detected by the shift position sensor 57 is Neutral N and the like. In the mode 2, the idling stop ECU 700 requests the engine ECU 710 to stop the fuel supply.
The idling stop ECU 700 is a brake ECU.
720 is requested to hold the brake state. The brake ECU 720 controls the brake actuator 47 to hold a brake hydraulic pressure corresponding to the amount of depression of the brake pedal.

When the idling stop ECU 700 determines that the operation of the engine 10 is stopped based on the detection data from the crank position sensor 54, the ECU 700 selects the mode 3 indicating the stopped state of the engine 10 due to the idling stop. In mode 3, the idling stop ECU
Reference numeral 700 turns on a display lamp on the instrument panel 46 to indicate that the idling stop control process is being executed.
In addition, the idling stop ECU 700 turns off the electromagnetic clutch 15 to release the connection between the crankshaft 11 and the transmission belts 16 and 17, and drives each accessory 30 by the accessory driving motor 31 via the transmission belt 17. Let it.

When detecting the idling stop control processing end request, the idling stop ECU 700 selects the mode 4 indicating the engine start control state for restarting the operation of the engine 10. Idling stop E
For example, when the shift position is shifted from neutral N to drive D, when the brake pedal is released, when the charge rate of the battery falls below a charge request value that is the lower limit of the charge rate, CU 700 cools the air conditioner. When the performance is insufficient or when any system abnormality occurs, a request for idling stop control processing is detected. In the present embodiment, when there is a re-start request for maintaining the vehicle state in a predetermined state excluding the driver's request for restarting the engine 10, a vibration control start control process described later is executed. You.

In the mode 4, the idling stop EC
U700 temporarily stops before the electromagnetic clutch 15 is engaged.
The auxiliary drive motor 31 is braked to drive the auxiliary drive motor 31
The number of rotations of The braking of the supplementary drive motor 31 is performed, for example, by inputting a reverse phase current. After the idling stop ECU 700 engages the electromagnetic clutch 15 at the engagement timing determined by the electromagnetic clutch engagement timing delay process described later, the idling stop ECU 700 changes the rotation speed of the auxiliary drive motor 31 to the engine startup rotation speed. And the engine ECU 710
Request for fuel supply and spark ignition. The idling stop ECU 700 selects the mode 0 when detecting an unusable system abnormality.

When the idling stop ECU 700 determines that the engine 10 is started, it selects the mode 1. The idling stop ECU 700 determines that the engine 10 has started, for example, when the engine speed detected by the crank position sensor 54 is 500 rpm or more. Idling stop ECU 700
Requests the brake ECU 720 to release the held brake hydraulic pressure. The brake ECU 720
The brake actuator 47 is controlled to release the held brake hydraulic pressure, thereby realizing a non-braking state. When the ignition position sensor 47 detects that the position is switched from ON to OFF in the mode 1 state, the idling stop ECU 700 selects the mode 0.

Next, the engine start control executed at the time of all starting of the engine 10 according to the present embodiment (at the time of restarting according to the idling stop control process and at the time of starting with the operation of the ignition key) is shown in FIGS. 10
This will be described with reference to FIG. FIG. 5 is a flowchart showing a processing routine of an engine start control process executed when the engine 10 is started. FIG. 6 is a flowchart showing a processing routine of the cylinder non-discrimination fuel injection control executed when the cylinder discrimination is not completed. FIG. 7 is a flowchart showing a processing routine of the fuel injection control at the time of cylinder discrimination executed when the cylinder discrimination is completed. FIG. 8 shows FIG.
It is a flowchart which shows the processing routine of fuel injection control at the time of cylinder discrimination which is performed when the cylinder discrimination subsequent to is completed. FIG. 9 is a flowchart showing a processing routine of the cylinder determination fuel injection control that is executed when the cylinder determination subsequent to FIG. 8 is completed. FIG. 10 is a timing chart showing the relationship among the crank rotation signal, the cylinder discrimination signal, the crank position, and the stroke of each cylinder 101.

The idling stop ECU 700 starts this processing routine when a request to start the engine 10 is issued. The idling stop ECU 700 determines whether or not the crank position has already been determined (step S100). When the crank position is determined, it is possible to execute the cylinder discrimination-time fuel injection control (described later) in which the fuel injection is selectively executed for the cylinder 101 that reaches the compression stroke while considering the fuel pressure Pf. Because.
Therefore, when it is determined that the crank position is determined (step S100: Yes), the idling stop ECU 700 does not perform the determination of the fuel pressure value in the present processing routine but executes the cylinder determination fuel injection processing described later. I do. On the other hand, if it is determined that the crank position has not been determined (step S100: NO), idling stop ECU 700 determines whether or not a missing tooth has been detected (step S110). That is, it is determined whether the missing tooth has been detected by the crank position sensor 54 as shown in FIG. By detecting this missing tooth, it is not possible to determine which cylinder 101 of the first and sixth cylinders reaches the top dead center in the compression stroke (that is, cylinder determination),
After the CA, it can be detected that the first cylinder or the sixth cylinder reaches the top dead center (TDC). If it is determined that the missing tooth has not been detected (step S110: No), the idling stop ECU 700 ends this processing because it cannot identify not only the crank position but also the strokes of all the cylinders 101. That is, the detection of the missing tooth is awaited.

On the other hand, the idling stop ECU 700
However, when it is determined that the missing tooth has been detected (step S110: Yes), it is determined whether the fuel pressure Pf detected by the fuel pressure sensor 50 is less than 10 MPa (step S120). The fuel pressure Pf is detected every 8 ms. If the fuel pressure Pf is 10 MPa or more, it is possible to inject fuel into the cylinder 101 against the internal pressure of the cylinder 101 (30 ° before top dead center (BTDC)) at the first ignition timing after cylinder determination. It is. On the other hand, when the fuel pressure Pf is less than 10 MPa, the cylinder 1
This is because fuel cannot be injected into the cylinder 101 against the internal pressure of 01 and the fuel injection timing needs to be changed to an earlier timing. The idling stop ECU 700 calculates the fuel pressure P
If it is determined that f is less than 10 MPa (step S120: Yes), the fuel injection control at the time of non-cylinder determination (step S130) is executed. As described above, the fuel pressure Pf
Is less than 10 MPa, the fuel cannot be injected into the cylinder 101 at the first ignition timing after the cylinder is determined even if the cylinder is in a standby state until the cylinder is determined, so that the missing tooth is detected without waiting for the cylinder determination. At that point, the fuel injection process is executed. The details of the cylinder non-discrimination fuel injection control will be described later.

On the other hand, the idling stop ECU 700
When it is determined that the fuel pressure Pf is equal to or higher than 10 MPa (step S120: No), the cylinder determination fuel injection control (step S140) is executed after the cylinder determination.
As can be seen from FIG. 10, the missing tooth is 120 ° from the detection.
After CA, the cylinder that reaches the ignition timing first (the cylinder that completes the compression stroke) is determined. More specifically, the cylinder discriminating signal (G
15) from the detection of missing teeth
It is possible to determine which of the plurality of cylinders 101 that will undergo the compression stroke or the exhaust stroke after 0 ° CA reaches the first ignition timing. In this embodiment, it is possible to determine which of the first cylinder and the sixth cylinder reaches the first ignition timing.

As described at the beginning of the description of the present processing routine, even if the cylinder has not been determined at the current timing (BTDC 150 ° CA of the first and sixth cylinders), the cylinder is determined (see FIG. If this processing routine is executed at the BTDC 30 ° CA of the first and sixth cylinders, the fuel injection control at the time of cylinder discrimination (step S14)
0) is executed.

Next, the fuel injection control when the cylinder is not determined will be described with reference to FIG. Idling stop ECU
700 determines whether or not the current start request is a request for ending the idling stop control process (step S200). Engine 1 after idling stop
When restarting the engine 10, the engine 10 is required to be restarted as early as possible (first ignition timing).
This is because if the engine is normally started with the operation of the ignition key, it is sufficient to start the engine after waiting for the cylinder discrimination. If it is determined that the engine is not in the restart mode after idling stop (mode 4) (step S200: No), the idling stop ECU 700 ends this processing in order to start the engine 10 after waiting for the cylinder discrimination. On the other hand, when the idling stop ECU 700 determines that the mode is the mode 4 (step S200: Y
es), it is determined whether or not the fuel pressure Pf detected by the fuel pressure sensor 50 is 5 MPa or more (Step S21)
0).

If the idling stop ECU 700 determines that the fuel pressure Pf is 5 MPa or more (step S210: Yes), it requests the engine ECU 710 to inject fuel into the first and sixth cylinders (step S220). That is, the fuel injection of the first and sixth cylinders at a BTDC of 150 ° (Fn1 in FIG. 10) is executed. The first and sixth cylinders at BTDC 150 ° are in the initial stage of the compression stroke, and the fuel pressure Pf is 5M.
This is because if the pressure is Pa or more, the fuel injection can be sufficiently performed against the pressure in the cylinder 101. As a result, ignition at the first ignition timing S1 can be realized. Since the determination of the ignition cylinder 101 by the ignition plug 13 is made after the completion of the cylinder discrimination, the spark ignition is executed only for the cylinder 101 which always ends the compression stroke.

On the other hand, the idling stop ECU 700
Determines that the fuel pressure Pf is less than 5 MPa (step S210: No), requests the engine ECU 710 to inject fuel into the second and fifth cylinders (step S230). That is, the fuel injection (Fn2 in FIG. 10) at the BTDC of 270 ° of the second and fifth cylinders is executed. When the fuel pressure Pf is less than 5 MPa, the fuel is reliably supplied into the cylinder 101 by executing the fuel injection in the intake stroke or the expansion stroke. As a result, the ignition timing becomes the second ignition timing S2.

The fuel injection to each cylinder 101 in this processing routine is performed first or two times when fuel injection is performed again for each cylinder 101 to which fuel has been injected in the following processing routine. The second ignition timing (S
1, S2) has a meaning as a pre-injection for further ensuring ignition.

Next, the fuel injection control at the time of cylinder discrimination will be described with reference to FIGS. The idling stop ECU 700 determines whether or not the cylinder discrimination signal (G signal) has occurred within 120 ° CA (G2 gate) from the detection of the missing tooth (step S300). The idling stop ECU 700 stores the G in the G2 gate as shown in FIG.
If no signal is detected (step S30)
0), the G signal flag Sg2 is turned off (step S31)
0). Note that the timing chart shown in FIG.
Since this is a timing chart when no G signal is generated in the gate, the following description mainly focuses on the G signal flag S.
The case where g2 is off will be described.

The idling stop ECU 700 determines whether the fuel pressure Pf is equal to or higher than 10 MPa (step S320). If it determines that the fuel pressure Pf is equal to or higher than 10 MPa (step S320: Yes), the idling stop ECU 700 shifts to the sixth cylinder. Is requested to engine ECU 710 (step S330). That is, the BT of the 6th cylinder
Fuel injection at DC 30 ° (Fd1 in FIG. 10) is executed. The reason why the injection cylinder is sharply distinguished by the fuel pressure Pf is that a high fuel pressure Pf is required to inject fuel into the cylinder 101 at this timing and execute ignition at the first ignition timing S1. is there. That is, the cylinder is determined only at the BTDC 30 ° of cylinders 1 and 6.
CA, and the pressure in the cylinder 101 in the latter half of the compression stroke is high. Therefore, in order to supply fuel into the cylinder 101 against the pressure inside the cylinder 101, 10M
A fuel pressure Pf of Pa or more is required. As described above, the engine ECU 710 executes fuel injection to the sixth cylinder, whereby the engine 10 can be restarted at the first ignition timing S1.

If it is determined that fuel pressure Pf is less than 10 MPa (step S320: No), idling stop ECU 700 determines whether fuel pressure Pf is 5 MPa or more (step S340). If the idling stop ECU 700 determines that the fuel pressure Pf is equal to or higher than 5 MPa (step S340: Ye
s) Fuel injection into the second cylinder is performed by the engine ECU 71.
0 (step S350). That is, the fuel injection at the BTDC of 150 ° of the second cylinder (Fd in FIG. 10)
Perform 2). Crank position of cylinder 2 is BTD
Since C150 ° (initial stage of the compression stroke), if the fuel pressure Pf is 5 MPa or more, the fuel can be sufficiently supplied into the cylinder 101. However, the ignition at the first ignition timing S1 cannot be executed, and the ignition at the second ignition timing S2,
The engine 10 is restarted.

If the idling stop ECU 700 determines that the fuel pressure Pf is less than 5 MPa (step S340: No), it requests the engine ECU 710 to inject fuel into the fourth cylinder (step S360).
That is, the fuel injection (Fd3 in FIG. 10) at the BTDC of 270 ° of the fourth cylinder is executed. Since the crank position of the 4th cylinder is BTDC 270 ° (intake stroke),
Even if the fuel pressure Pf is less than 5 MPa, the fuel is sufficiently supplied into the cylinder 101 by the intake negative pressure. However, the ignition at the first ignition timing S1 cannot be executed, and the ignition at the second ignition timing S2 at the second cylinder or the ignition at the third ignition timing S3 at the fourth cylinder and the restart of the engine 10 are performed. .

When the generation of the G signal in the G2 gate is detected in step S300 (step S300: Ye
s), and turns on the G signal flag Sg2 (step S37)
0), and thereafter, the cylinder 101 for executing the fuel injection is determined according to the fuel pressure Pf. Note that the determination process of the fuel pressure Pf is the same as the case where the generation of the G signal is not detected in the G2 gate, so that the description is simplified by attaching step numbers.
The idling stop ECU 700 determines that the fuel pressure Pf is 10
If the pressure is equal to or higher than MPa (Step S380: Yes),
A request is made to engine ECU 710 to execute fuel injection to the first cylinder (step S390). The idling stop ECU 700 determines that the fuel pressure Pf is 10 MPa.
(Step S380: No) and 5MP
a (step S400: Yes), the engine EC performs fuel injection to the fifth cylinder.
A request is made to U710 (step S410). If the fuel pressure Pf is less than 5 MPa (step S400: No), the idling stop ECU 700 requests the engine ECU 710 to execute fuel injection to the third cylinder (step S420).

When the first fuel injection process ends, the idling stop ECU 700 executes the second fuel injection process. First, the idling stop ECU 700
Determines whether the fuel pressure Pf is equal to or higher than 5 MPa (step S430). Idling stop ECU 7
In the case of 00, when it is determined that the fuel pressure Pf is less than 5 MPa (Step S430: No), the present processing routine ends. If the fuel pressure Pf is less than 5 MPa at this point, the fuel injection to the compression stroke becomes impossible in the subsequent fuel injection control processing, so the present processing routine ends. Even in such a case, fuel is supplied to the fourth or third cylinder, and ignition is performed at the latest at the third ignition timing S3. Also, depending on the rise of the fuel pressure Pf,
Fuel injection and ignition into the second or fifth cylinder at the previous second ignition timing S2 can be executed.

If the idling stop ECU 700 determines that the fuel pressure Pf is equal to or higher than 5 MPa (step S430: Yes), it determines whether the G signal flag Sg2 is ON (step S440). As described above, the timing chart of FIG.
Each timing in the case of F is shown. When determining that the G signal Sg2 is OFF (step S440: No), the idling stop ECU 700 determines whether the fuel pressure Pf is equal to or higher than 10 MPa (step S450). At this point, the second cylinder is TDC
Therefore, it is determined whether fuel injection into the second cylinder at a BTDC of 30 ° CA is possible. The idling stop ECU 700 has a fuel pressure Pf of 10M.
If it is determined that the pressure is equal to or higher than Pa (step S45).
0: Yes) The fuel injection to the second cylinder is performed by the engine E
A request is made to the CU 710 (step S460). As a result, fuel injection is performed at BTDC 30 ° CA of the second cylinder (Fd4), and ignition is performed at the second ignition timing S2. If the fuel injection to the second cylinder has been performed in step S350, the previous fuel injection functions as a pre-injection. In such a case, the second ignition timing S
2 enables more reliable ignition.

On the other hand, the idling stop ECU 700
Determines that the fuel pressure Pf is less than 10 MPa (step S450: No), requests the engine ECU 710 to inject fuel into the fourth cylinder (step S4).
70). As a result, the fourth cylinder BTDC 150 ° C
A, fuel injection is executed (Fd5), and the third ignition timing S
The ignition is performed on 3. If the fuel injection to the fourth cylinder has been performed in step S360, the previous fuel injection functions as a pre-injection. In such cases,
More reliable ignition at the third ignition timing S3 becomes possible.

The idling stop ECU 700 calculates the G
If it is determined that the signal flag Sg2 is ON (step S440: Yes), it is determined whether the fuel pressure Pf is equal to or higher than 10 MPa (step S480). If the fuel pressure Pf is equal to or higher than 10 MPa (step S480: Ye
s) The fuel injection to the fifth cylinder is performed by the engine ECU 71.
0 is requested (step S490). In contrast, the idling stop ECU 700 determines that the fuel pressure Pf is 10 M
If it is determined that it is less than Pa (Step S43)
0: No) Fuel injection to the third cylinder is performed by the engine EC
A request is made to U710 (step S500). As a result,
The ignition is performed at the third ignition timing. Previous step S4
When fuel injection to the third cylinder is performed at 00, the previous fuel injection functions as pre-injection. In such a case, more reliable ignition at the third ignition timing is possible.

When the second fuel injection is completed in this way, the idling stop ECU 700 executes the third fuel injection control. First, the idling stop ECU 700 determines whether the fuel pressure Pf is equal to or higher than 10 MPa (step S510). At this point, the fuel pressure P
When f is less than 10 MPa (Step S510: No)
Then, in the subsequent fuel injection control processing, fuel injection to the compression stroke becomes impossible, and thus this processing routine is terminated.
Even in such a case, the fuel is already supplied to the fourth or third cylinder, and the third ignition timing S
At 3, ignition is performed.

If the idling stop ECU 700 determines that the fuel pressure Pf is equal to or greater than 10 MPa (step S510: Yes), it determines whether the G signal flag is ON (step S520). If the idling stop ECU 700 determines that the G signal flag is OFF (step S520: No), it requests the engine ECU 710 to inject fuel into the fourth cylinder (step S530). On the other hand, if the idling stop ECU 700 determines that the G signal flag is ON (step S520: Yes), it requests the engine ECU 710 to inject fuel into the third cylinder (step S540). As a result, the fourth cylinder BTDC3
Fuel injection is performed at 0 ° CA, and ignition is performed at Fd6 and the third ignition timing S3. When fuel injection to the third or fourth cylinder has been executed in the previous step S470 or S500, the previous fuel injection functions as a pre-injection. In such a case, the third ignition timing S
3 enables more reliable ignition.

As described above, according to the starting control apparatus according to the present embodiment, when the fuel pressure is sufficiently high (10 MPa or more), the cylinder 101 that first reaches the ignition timing waits for cylinder discrimination. On the other hand, since the fuel injection can be executed, the engine 10 can be restarted at the earliest stage, that is, at the ignition timing S1. That is, fuel injection in the latter half of the compression stroke that can be performed only by the direct injection engine can be executed even when the engine 10 is started. Further, since the fuel is injected only to the cylinder 101 whose cylinder has been determined, the exhaust gas characteristics can be improved without discharging the unburned gas.

If the cylinder discrimination has been completed,
Even if the fuel pressure Pf is not high enough to allow fuel injection at BTDC 30 ° CA (less than 10 MPa), the cylinder 101 that reaches the ignition timing earliest according to the fuel pressure Pm
And inject fuel. Thereby, the engine 10
In addition, since the fuel is injected only to the cylinder 101 whose cylinder has been determined, the unburned gas is not discharged, and the exhaust gas characteristics can be improved.

Further, even if the cylinder discrimination has not been completed and the fuel pressure Pf is not high enough to permit fuel injection at BTDC 30 ° CA, if the fuel pressure Pf is relatively high (5 MPa) Above 10 MPa), the cylinder group (specific cylinder group) that first reaches the ignition timing
Since fuel injection at TDC 150 ° CA is performed, the first
The engine 10 can be surely restarted at the second ignition timing S1. If the fuel pressure Pf is relatively low (less than 5 MPa) in the same state, the fuel injection at BTDC 270 ° CA is performed for the cylinder group that reaches the second ignition timing. The engine 10 can be reliably restarted at the ignition timing S2.

As described above, the engine 10 according to the present embodiment
With the use of the start control device, the engine 10 can be started as early as possible while utilizing the advantages of the direct injection engine according to the fuel pressure Pf.

Next, a description will be given, with reference to FIGS. 11 and 12, of a restart-time engine start control process executed when the engine 10 is restarted in response to a request from the vehicle. FIG. 11 is a flowchart illustrating a processing routine that is executed when the engine 10 is restarted in response to a request from the vehicle in an idling stop state in which the idling operation of the engine is stopped. FIG. 12 shows the intake pipe pressure P at the time of engine restart based on the vehicle side request.
m, motor rotation speed Nm for driving auxiliary equipment, engine rotation speed Ne
6 is a timing chart showing a change with time.

The idling stop ECU 700 determines whether or not the mode 4 indicating the engine start control state for restarting the operation of the engine 10 has been selected (step S600). Idling stop ECU 7
In the case of 00, when it is determined that the mode 4 has not been selected (step S600: No), the present process is terminated, and when it is determined that the mode 4 has been selected (step S60).
0: Yes), it is determined whether or not the request to restart the engine 10 is based on a request from the vehicle (step S610). As described above, when the engine 10 is restarted, the supplementary drive motor 31 is braked by inputting the reverse phase current as shown in FIG. 12, and the rotation speed Nm decreases. When the rotational speed Nm of the supplementary drive motor 31 decreases to a predetermined rotational speed, the electromagnetic clutch 15 is engaged, and the rotor of the supplementary drive motor 31 and the crankshaft 11 of the engine 10 are connected.
After the electromagnetic clutch 15 is engaged, the engine 10 is cranked (motored) by the supplementary drive motor 31. At the time of cranking, cylinder determination is also performed, and the first fuel injection is performed after the cylinder determination. In addition,
When executing this processing routine, the throttle valve 1
Reference numeral 22 is substantially completely closed, and regulates the amount of air taken into the cylinder 101.

The cause of the request for restarting the engine 10 from the vehicle side is that the driver does not operate the accelerator pedal and the brake pedal. For example, the charge rate of the battery falls below the charge request value which is the lower limit of the charge rate. When the cooling performance of the air conditioner is insufficient. When such a factor is used, a quick restart of the engine 10 is not required, but rather, it is required to suppress an impact, a vibration, and the like accompanying the restart of the engine 10. Therefore,
In this embodiment, cranking by the supplementary drive motor 31 is performed until the intake pipe pressure Pm becomes equal to or less than a predetermined value while the throttle valve 122 is substantially fully closed, and the pressure in the cylinder 101 (the intake pipe pressure When Pm) becomes equal to or lower than a predetermined pressure (negative pressure), the start of the engine 10 is started. That is, if cranking is continued while the throttle valve 122 is substantially fully closed, as shown in FIG. 12, the rotation speed Nm of the supplementary drive motor 31 increases, and the intake pipe pressure Pm eventually becomes negative. Cylinder 101
It means that the amount of intake air to the inside is decreasing.

The idling stop ECU 700 determines whether the intake pipe pressure Pm detected by the intake pressure sensor 51 is equal to or less than the intake pipe pressure determination value Pmref (step S620). This intake pipe pressure determination value Pmref
Is set so that the amount of intake air into the cylinder 101 is reduced and the torque (combustion pressure) generated by the first explosive combustion of the engine 10 becomes sufficiently small. When determining that the intake pipe pressure Pm is equal to or less than the intake pipe pressure determination value Pmref (step S620: Yes), the idling stop ECU 700 injects fuel into the cylinder 101 determined by the cylinder determination as shown in FIG. At the start (step S630), an ignition process is executed to restart the engine 10. Thus, the cylinder 10
If the pressure in the cylinder 1 is reduced to a negative pressure to reduce the amount of intake air into the cylinder 101, the torque generated at the time of starting the engine 10 becomes small, and a rapid torque fluctuation can be suppressed. As a result, the rotation speed Ne of the engine 10 gradually increases as shown in FIG. Generally, the intake pipe pressure Pm when the engine is stopped converges to the atmospheric pressure as the engine stop time increases, and the pressure in the cylinder 101 also shows the same behavior. In the conventional restart control, since the engine 10 is started in this state, a large amount of intake air is introduced into the cylinder 101, and a large torque is generated by explosive combustion. Such a sudden torque change improves drivability when it is caused by the driver's will, but gives a sense of incongruity when it is based on a request from the vehicle.

On the other hand, the idling stop ECU 700
When it is determined that the intake pipe pressure Pm is larger than the intake pipe pressure determination value Pmref (Step S620: No),
The elapsed time ΔTs from the start of the start is equal to the start elapsed time determination value T.
It is determined whether or not ref is greater than or equal to ref (step S64)
0). If the idling stop ECU 700 determines that the elapsed time ΔTs <Tref (step S
640: No), and again compare the intake pipe pressure Pm with the intake pipe pressure determination value Pmref (step S62).
0). If the idling stop ECU 700 determines that the elapsed time ΔTs ≧ Tref (step S
640: Yes), a notification that an abnormality has occurred in the intake system is made via the instrument panel 46 (step S650), and the fuel injection to the cylinder 101 determined by the cylinder discrimination to prevent the battery from running out is performed. The process is started (step S630), and the engine 10 is restarted via the ignition process. That is, the reliable restart of the engine 10 is prioritized over the suppression of the shock and vibration generated at the time of starting.

As described above, in this embodiment, when the engine 10 is restarted based on the vehicle-side start request, the cylinder 10
Since the amount of air taken into the engine 1 is reduced to suppress the torque generated due to the explosion combustion, it is possible to suppress the torque fluctuation generated when the engine 10 is restarted. Can be reduced. In particular,
Starting the engine 10 irrespective of the driver's will gives the driver a sense of discomfort, but by suppressing the impact and vibration associated with the restart of the engine 10, such discomfort can be reduced.

The start control apparatus for an internal combustion engine according to the present invention has been described above based on some embodiments of the present invention. It is not intended to limit the invention. The present invention can be modified and improved without departing from the spirit and scope of the claims, and it is needless to say that the present invention includes equivalents thereof.

For example, in the above embodiment, the start control apparatus for an internal combustion engine according to the present invention has been described based on a vehicle having an idling stop function. The invention can be applied to any vehicle. Even when starting with ignition key operation,
There is a request for early start of the engine 10, and the request can be met by using the start control device according to the present invention.
In addition, since the fuel injection is selectively executed for the cylinder at which the ignition timing is reached, the emission of unburned gas can be suppressed.

In the above-described embodiment, the compression stroke (B
The fuel pressure value of 10 MPa is used to determine whether or not to execute the fuel injection at TDC 30 ° CA), and the initial stage of the compression stroke (BTDC1
The fuel pressure value of 5 MPa is used to determine whether to execute the fuel injection at 50 ° CA). However, these fuel pressure values are merely examples, and it is sufficient that fuel can be injected into the cylinder against the cylinder pressure at each time, and can be appropriately changed based on the compression ratio of the engine and the like.

Further, in the above embodiment, the description has been made using the six-cylinder engine.
It can be used not only for other multi-cylinder engines such as cylinders but also for single-cylinder engines.

Further, in the above embodiment, values such as 10 MPa and 5 MPa are used as the judgment values of the fuel pressure. However, these values are appropriately changed depending on the pressure in the compression stroke of the engine. Higher fuel pressure values may be used, and lower fuel pressure values may be used in engines with lower compression ratios. That is, any pressure may be used as long as fuel can be injected against the in-cylinder pressure in the compression stroke.

In the above-described embodiment, the damper is built in the electromagnetic clutch 15, but the electromagnetic clutch 15 and the damper may be provided separately. Further, for convenience of explanation, the crankshaft pulley 125 and the electromagnetic clutch 15 are separately illustrated in FIG. 1, but the electromagnetic clutch 15 may be built in the crankshaft pulley 125.

In the above embodiment, the transmission 22
Although an automatic stepped transmission is used as the above, a manual transmission or an automatic stepless transmission may be used instead of the automatic stepped transmission. In any case, the idling stop control process can be executed, and the same advantage as that obtained by using the automatic stepped transmission can be obtained.

In the above embodiment, the present invention has been described based on a vehicle having only the engine 10 as a driving force source of the vehicle. However, the present invention relates to a hybrid vehicle having an engine and a vehicle driving motor as a driving force source. May also be applied. Even in such a case, when a direct injection type engine is provided as the engine, a similar problem occurs at the time of starting,
These problems can be solved by applying the present invention. Further, in a hybrid vehicle, the engine may be started by a request from the vehicle after idling stop including during running of the motor, and in such a case, if the restart control of the internal combustion engine according to the present embodiment is executed, the engine is restarted. The vibration caused by the restart is suppressed, and the discomfort given to the occupant when the engine is restarted can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a vehicle to which an embodiment according to the present invention is applied.

FIG. 2 is an explanatory diagram showing a schematic configuration around an engine used in an embodiment according to the present invention.

FIG. 3 is an explanatory diagram showing a control system of the vehicle according to the embodiment according to the present invention.

FIG. 4 is a state transition diagram showing a transition state of control processing during idling stop control processing.

FIG. 5 is a flowchart showing a processing routine of an engine start control process executed when the engine 10 is started.

FIG. 6 is a flowchart illustrating a processing routine of fuel injection control during non-cylinder determination performed when cylinder determination is not completed.

FIG. 7 is a flowchart showing a processing routine of fuel injection control at the time of cylinder discrimination executed when cylinder discrimination is completed.

FIG. 8 is a flowchart illustrating a processing routine of cylinder-difference fuel injection control that is executed when the cylinder determination subsequent to FIG. 7 is completed.

FIG. 9 is a flowchart showing a processing routine of fuel injection control at the time of cylinder discrimination executed when cylinder discrimination following FIG. 8 is completed.

FIG. 10 is a timing chart showing a relationship among a crank rotation signal, a cylinder discrimination signal, a crank position, and a stroke of each cylinder 101.

FIG. 11 is a flowchart illustrating a processing routine that is executed when the engine 10 is restarted in response to a request from the vehicle in an idling stop state in which the idling operation of the engine is stopped.

FIG. 12 is a timing chart showing changes over time of an intake pipe pressure Pm, an auxiliary device driving motor rotation speed Nm, and an engine rotation speed Ne at the time of engine restart based on a vehicle request.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Engine 11 ... Crankshaft 12 ... Injector 13 ... Spark plug 14 ... Igniter 15 ... Multiplate electromagnetic clutch 16, 17 ... Transmission belt 18 ... Delivery pipe 20 ... Torque converter 22 ... Automatic stepped transmission (AT) 24 ... Drive shaft 25 ... Differential gear 26 ... Axle 27 ... Wheels 30 ... Auxiliary equipment 31 ... Auxiliary equipment drive motor 40 ... Ring gear 41 ... Starting motor 45 ... Oil pump drive motor 46 ... Instrument panel 47 ... Brake actuator 50 ... Temperature sensor 51 ... Outside air temperature sensor 52 ... Motor speed sensor 53 ... Engine speed sensor 56 ... Vehicle speed sensor 57 ... Shift position sensor 58 ... Accelerator opening sensor 59 ... Brake pedal sensor 60 ... Ignition position sensor 70 ... Control unit G 101 ... cylinder 102 ... cylinder head 103 ... intake port 104 ... exhaust port 105 ... cylinder block 110 ... intake valve 111 ... exhaust valve 112 ... cam shaft 113 ... cam 120 ... intake pipe 121 ... surge tank 122 ... throttle valve 151 ... clutch Plate 152 Flywheel 160 Accessory pulley 161 Crankshaft pulley 162 Accessory drive motor pulley 200 Inverter 210 High voltage battery 220 DC / DC converter 230 Battery 700 700 Idling stop ECU 710 Engine ECU 720 Brake ECU

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) F02D 43/00 301 F02D 43/00 301J 45/00 362 45/00 362E 368 368S F02P 5/15 F02P 5/15 E ( 72) Inventor Atsushi Takahashi 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Noichi 1 Toyota Town Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Atsushi Kitamura Aichi 1 Toyota Town, Toyota City F-term in Toyota Motor Corporation (reference) 3G022 BA01 CA01 CA03 EA01 FA02 GA00 GA01 GA02 3G084 AA00 BA13 BA15 BA17 CA01 CA07 DA00 DA09 DA10 DA39 EA07 EA11 EB22 FA00 FA05 FA06 FA11 FA21 FA38 FA39 3G092AA AA06 AA11 AB02 AC03 BA09 BA10 BB06 BB10 BB18 CA02 CB04 CB05 DE03S EA09 EA17 FA14 FA15 FA30 FA32 GA01 GB01 GB10 HA05Z HB03Z HC01Z HE04Z HE05Z HF02Z DA12BA03A02BA03A03A04A03 DA03 DA07 DB00 DB05 DB12 DB15 DB23 EA00 EA05 EA13 FA11 FB02 3G301 HA01 HA04 HA19 JA00 JA21 JA37 JB10 KA04 KA28 KB01 LA00 LB04 MA19 MA24 NA08 NE23 PA07Z PB08Z PC01Z PE04Z PE05Z PF01Z PF05Z PF08ZPF

Claims (21)

[Claims] 1. A fuel injection control device for a start-up of an internal combustion engine, comprising: a fuel injection valve for directly injecting fuel pressurized by a booster using an internal combustion engine as a power source into a cylinder. Fuel pressure detecting means for detecting the pressure of fuel which can be injected by the fuel injection timing determining means for determining the timing of fuel injection in a combustion cycle according to the detected fuel pressure; and An injection control means for injecting fuel via the fuel injection valve; 2. The fuel injection control device for starting an internal combustion engine according to claim 1, wherein the internal combustion engine has a plurality of cylinders, and each of the cylinders is provided with the fuel injection valve. A start-up fuel injection control device for an internal combustion engine, comprising: a cylinder discriminating unit that discriminates a cylinder at an injection timing determined by the fuel injection timing determining unit from among the plurality of cylinders. 3. The fuel injection control device for starting an internal combustion engine according to claim 1, wherein said fuel injection timing determining means determines whether or not the pressure of the fuel is higher than a first pressure. A starting fuel injection control device for an internal combustion engine, wherein a stroke is determined at a fuel injection timing. 4. The fuel injection control device for starting an internal combustion engine according to claim 3, wherein said fuel injection timing determining means performs a fuel injection stroke when said fuel pressure is lower than said first pressure. A start-time fuel injection control device for an internal combustion engine, which determines an injection timing. 5. The fuel injection control device for starting an internal combustion engine according to claim 3, wherein the fuel injection timing determining means is configured to determine that the fuel pressure is equal to or higher than a second pressure higher than the first pressure. A fuel injection control device for starting the internal combustion engine, wherein the latter half of the compression stroke is determined as the fuel injection timing. 6. The fuel injection control device for starting an internal combustion engine according to claim 5, wherein the fuel injection timing determining means is configured to determine that the pressure of the fuel is lower than the second pressure and higher than the first pressure. In Case of,
A fuel injection control device for starting an internal combustion engine, wherein a first half of a compression stroke is determined as a fuel injection timing. 7. The fuel injection control device for starting an internal combustion engine according to claim 1, further comprising: an in-cylinder pressure detecting means for detecting a pressure in the cylinder; Start request determining means for determining whether or not the start request is based on a vehicle start request, wherein the injection control means determines that the start request is not based on the vehicle start request. A fuel injection control device for starting an internal combustion engine, wherein fuel injection to the determined cylinder is started after the detected in-cylinder pressure becomes equal to or less than a predetermined value. 8. A start control of an internal combustion engine having a plurality of cylinders and a fuel injection device for directly injecting fuel boosted by a booster using an internal combustion engine as a power source into each cylinder is provided for each cylinder. A fuel pressure detection unit that detects a pressure of fuel injected by the fuel injection device; a cylinder determination unit that determines a compression stroke cylinder in a compression stroke of the plurality of cylinders; Based on the determination result, and the detected fuel pressure, first injection cylinder determining means for determining a first injection cylinder to first inject fuel at the time of starting the internal combustion engine, and for the determined first injection cylinder, Starting means for injecting fuel via the fuel injection device and performing ignition to start the internal combustion engine. 9. The start control apparatus for an internal combustion engine according to claim 8, wherein said first injection cylinder determining means determines whether said detected fuel pressure is equal to or higher than a first pressure by said cylinder determining means. A start control device, wherein the determined compression stroke cylinder is determined as a first injection cylinder. 10. The start control device for an internal combustion engine according to claim 8, wherein the detected fuel pressure is lower than the first pressure and equal to or higher than a second pressure lower than the first pressure. In the start control apparatus for an internal combustion engine, a next compression stroke cylinder which reaches a compression stroke next to the compression stroke cylinder is determined as a first injection cylinder. 11. The start control device for an internal combustion engine according to claim 10, wherein when the detected pressure of the fuel is lower than the second pressure, the next compression stroke cylinder is followed by a compression stroke. A start control device for an internal combustion engine, wherein a next compression stroke cylinder is determined as a first injection cylinder. 12. The internal combustion engine start control device according to claim 9, further comprising: an in-cylinder pressure detecting means for detecting the pressure in the cylinder; and a vehicle start requesting that the start request of the internal combustion engine requests a start of the vehicle. Start request determining means for determining whether or not the start request is based on the request. The start means determines the detected cylinder when it is determined that the start request is not based on the vehicle start request. A start control device for an internal combustion engine, which executes fuel injection and ignition to the determined first injection cylinder after the internal pressure becomes equal to or less than a predetermined value. 13. A start control of an internal combustion engine having a plurality of cylinders and a fuel injection device for directly injecting fuel boosted by a booster using an internal combustion engine as a power source into each cylinder. An apparatus, comprising: a fuel pressure detecting means for detecting a pressure of fuel injected by the fuel injection device; and a cylinder group identification for identifying a specific cylinder group in an initial stroke of a compression stroke or an exhaust stroke of the plurality of cylinders. Means, after the specific cylinder group is identified, a cylinder determining means for determining a compression stroke cylinder in a compression stroke of the specific cylinder group, an identification result by the cylinder group identifying means, A first-injection-cylinder determining means for determining a first-injection cylinder for first injecting fuel when the internal combustion engine is started, based on the determination result and the detected fuel pressure; Start control system for an internal combustion engine and a starting means for starting the internal combustion engine is running the ignition as well as injecting the fuel through the fuel injector to the constant has been first injection cylinder. 14. The start control apparatus for an internal combustion engine according to claim 13, wherein said first injection cylinder determining means has identified said specific cylinder group but has not determined said compression stroke cylinder, If the detected fuel pressure is equal to or higher than the first pressure,
A start control device characterized by waiting for determination of the compression stroke cylinder of the cylinder by the cylinder determination means, and when the compression stroke cylinder is determined, determining the compression stroke cylinder as the first injection cylinder. 15. The start control device for an internal combustion engine according to claim 14, wherein the detected fuel pressure is lower than the first pressure and equal to or higher than a second pressure lower than the first pressure. In the first aspect, the identified specific cylinder group is determined as the first injection cylinder. 16. The starting control device for an internal combustion engine according to claim 15, wherein when the detected fuel pressure is lower than the second pressure, a compression stroke or an exhaust stroke is provided next to the specific cylinder group. A start control device for an internal combustion engine, wherein a cylinder group reaching a stroke is determined as a first injection cylinder. 17. A vehicle comprising the internal combustion engine start control device according to claim 8. 18. The vehicle according to claim 17, further comprising: idling control means for stopping an idling operation of the internal combustion engine in accordance with a state of the vehicle, and restarting the operation of the internal combustion engine having stopped the idling operation. A vehicle according to claim 1, wherein restart of operation of the internal combustion engine is controlled by the start control device when restarting operation of the internal combustion engine. 19. A vehicle comprising the fuel injection control device according to any one of claims 1 to 7. 20. The vehicle according to claim 19, further comprising: idling control means for stopping an idling operation of the internal combustion engine in accordance with a state of the vehicle, and restarting the operation of the internal combustion engine having stopped the idling operation. A vehicle, wherein when the operation of the internal combustion engine is restarted, supply of fuel to the internal combustion engine is controlled by the fuel injection control device. 21. Start control in an internal combustion engine having a plurality of cylinders, each of which is provided with a fuel injection device for directly injecting a fuel boosted by a booster using an internal combustion engine as a power source into each cylinder. A method for detecting a pressure of fuel injectable by the fuel injection device, and detecting a cylinder group identification signal indicating that a specific cylinder group of the plurality of cylinders is in an initial stroke of a compression stroke or an exhaust stroke. Detecting a cylinder discrimination signal for discriminating a compression stroke cylinder in a compression stroke of the specific cylinder group, the cylinder group identification signal, and a cylinder discrimination signal detected after detecting the cylinder group identification signal. Based on the detected fuel pressure, the first injection cylinder that first injects fuel when the internal combustion engine is started is determined, and before the first injection cylinder reaches ignition timing, the cylinder group is determined. Determining an ignition cylinder based on another signal and a cylinder discrimination signal detected after detecting the cylinder group identification signal; and injecting fuel through the fuel injection device to the determined first injection cylinder and the ignition cylinder. A start control method for an internal combustion engine for starting the internal combustion engine by executing ignition on the engine.