JPH09170469A - Fuel injection controller for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure start-up of an engine by enabling fuel ignition for initial explosion to be carried out in an asynchronous manner with the revolution of engine before the completion of discrimination of cylinder at the time of start-up of the engine, and enabling fuel ignition to be carried out until the revolution exceeds a complete explosion detection revolution in a synchronous manner therewith. SOLUTION: An ECU for electronically controlling an engine 1 is composed of a main computer and a sub-computer, and the main computer processes detection signals from sensor switches and battery voltage or the like and computes fuel ignition, ignition timming, and various control quantities to an idle speed control valve 11, based on various data and the like. The fuel injection for initial explosion is set according to conditions of the engine 1, and the injection is carried out in an asynchronous manner with the revolution of the engine 1 before discrimination of cylinder at start-up of the engine 1 is completed. After the completion of discrimination, the fuel injection for start-up is carried out in synchronization with the revolution of engine until it exceeds a complete explosion discrimination revolution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to an engine fuel injection control device capable of easily obtaining an initial explosion and smoothly shifting from the initial explosion to a complete explosion.

[0002]

As is well known, when starting an engine,
Control with an air-fuel ratio that is richer than normal is required, and the engine speed gradually increases after the first initial explosion due to cranking, and when the complete explosion speed is reached, control with the normal air-fuel ratio is performed. Can be switched to.

In this case, conventionally, the fuel injection amount is increased and corrected depending on the engine temperature such as the cooling water temperature, and the starting control is uniquely performed with the same air-fuel ratio from the cranking to the complete explosion. As a result, the air-fuel ratio becomes unnecessarily overrich when transitioning from the initial explosion to a stable complete-explosion state at low temperature startup, and after the initial explosion due to a decrease in the fuel supply amount due to vaporization of the fuel system at high temperature startup. However, there is a problem that the air-fuel ratio becomes lean and it is difficult to obtain a smooth start.

For this reason, the applicant of the present invention has previously disclosed in Japanese Patent Laid-Open No.
In Japanese Patent No. 146240, when the engine is started, the fuel of the fuel injection amount at the start of initial combustion is supplied until the engine speed exceeds the initial explosion engine speed setting value, and then the engine speed is set to the complete explosion engine speed setting value. It proposes a technology to smoothly transition from the initial explosion to the complete explosion by supplying the fuel at the amount of fuel injection at the time of starting the complete explosion until it exceeds.

[0005]

Generally, the fuel injection amount required for the initial explosion is such that the fuel injected from the injector adheres to the intake manifold wall surface, the intake valve, the combustion chamber inner wall, etc. and is not effectively contributed to combustion. In order to correct the above, it is necessary to set the amount larger than the fuel injection amount for complete explosion.

Therefore, in the technique proposed by the present application, even if the engine is cranked and the first explosion occurs in any of the cylinders and burns, the engine speed exceeds the initial explosion engine speed set value. Until then, a large amount of fuel injection for the initial explosion will continue to be supplied to the engine, and the problem that the spark plug gets wet and smolders before the complete explosion,
There was room for improvement against the problem that the air-fuel mixture would be too rich and stall even after the first explosion.

Further, depending on how the initial combustion fuel injection amount and the complete combustion fuel injection amount are set, a step may occur between the initial combustion fuel injection amount and the complete combustion fuel injection amount. Immediately after the determination is made, there is an aspect that the countermeasures against the engine speed fluctuation such as the increase of the engine speed is stagnant are not always sufficient.

The present invention has been made in view of the above circumstances, and it is possible to easily obtain an initial explosion at the time of engine startup, and to make a smooth transition from the initial explosion to a complete explosion to ensure engine startup. An object of the present invention is to provide a fuel injection control device for an engine capable of achieving the above.

[0009]

According to the first aspect of the present invention,
As shown in the basic configuration diagram of FIG. 1 (a), the initial combustion fuel injection amount setting for setting the initial combustion fuel injection amount for obtaining an air-fuel ratio suitable for the initial combustion at engine start depending on the engine state Means, a starting fuel injection amount setting means for setting the starting fuel injection amount for obtaining an appropriate air-fuel ratio from the initial explosion to the complete explosion according to the engine state, and the initial fuel injection amount setting means The fuel injection amount for the initial explosion is injected asynchronously with the engine rotation before the cylinder discrimination at the engine start is completed, and after the cylinder discrimination is completed, the starting fuel injection amount set by the starting fuel injection amount setting means is set to the engine. An injection control means for injecting in synchronism with the engine rotation until the rotation speed exceeds a preset complete explosion determination rotation speed is provided.

According to the second aspect of the present invention, as shown in the basic configuration diagram of FIG. 1 (b), the initial combustion fuel injection amount for obtaining the air-fuel ratio suitable for the initial combustion at engine start is set to the engine state. Initial combustion fuel injection amount setting means to be set accordingly, and starting fuel injection amount setting means to set the starting fuel injection amount to obtain an appropriate air-fuel ratio from initial explosion to complete explosion, according to the engine state, When the crank angle signal is input a set number of times before the cylinder discrimination at the time of engine start is completed, the fuel injection amount for initial explosion set by the fuel injection amount for initial explosion setting means is injected, and after completion of cylinder discrimination, An injection control unit for injecting the starting fuel injection amount set by the starting fuel injection amount setting unit until the engine speed exceeds a preset complete explosion determination rotation speed is provided.

According to the third aspect of the invention, as shown in the basic configuration diagram of FIG. 1 (c), the starting fuel injection amount for obtaining an appropriate air-fuel ratio from initial explosion to complete explosion at engine start is set to the engine state. Starting fuel injection amount setting means set according to
A fuel injection correction amount for initial explosion for correcting the fuel injection amount for starting to match the air-fuel ratio for obtaining the initial explosion is set according to the engine state, and this fuel injection correction amount for initial explosion is used for fuel injection. Initial injection fuel injection correction amount setting means for attenuating according to history, and starting fuel injection amount set by the starting fuel injection amount setting means until the engine speed exceeds a preset complete explosion determination rotation speed And an injection control unit for adding and injecting the initial combustion fuel injection correction amount set by the initial combustion fuel injection correction amount setting unit.

According to a fourth aspect of the present invention, in the first or second aspect of the present invention, the injection control means only makes a fuel injection for the initial explosion only when there is a history of complete explosion at the last engine start. It is characterized by ejecting an amount.

That is, according to the first aspect of the present invention, when the engine is started, the initial combustion fuel injection amount set according to the engine state before the completion of the cylinder discrimination is injected asynchronously with the engine rotation so that the initial combustion occurs. After the cylinder discrimination is completed, the starting fuel injection amount set according to the engine state is synchronized with the engine rotation speed until the engine rotation speed exceeds a preset complete explosion determination rotation speed so as to obtain an appropriate air-fuel ratio. It is injected to obtain the proper air-fuel ratio from the initial explosion to the complete explosion.

According to the second aspect of the present invention, when the engine is started and the crank angle signal is input a set number of times before the cylinder discrimination is completed, the initial combustion fuel injection amount set according to the engine state is injected. In order to obtain the air-fuel ratio suitable for the initial explosion, after the cylinder discrimination is completed, the starting fuel injection amount set according to the engine state is injected until the engine speed exceeds the preset complete explosion judgment speed. , Get the proper air-fuel ratio from the first explosion to the complete explosion.

In this case, according to the invention described in claim 4,
The fuel injection amount for initial explosion in the invention according to claim 1 or the invention according to claim 2 is injected only when there is a history of complete explosion at the previous engine start.

According to the third aspect of the present invention, when the engine is started, the initial combustion fuel injection correction amount is added to the starting fuel injection amount for obtaining the proper air-fuel ratio from the initial combustion to the complete combustion. Corrected to match the air-fuel ratio to obtain the initial explosion, and start while reducing the initial injection fuel injection correction amount according to the fuel injection history until the engine speed exceeds the preset complete explosion determination rotation speed It is added to the fuel injection amount for injection.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. 2 to 11 relate to the first embodiment of the present invention, FIG. 2 is a flowchart of a starting all cylinders simultaneous injection setting routine, FIGS. 3 to 5 are flowcharts of a Ti setting routine, and FIG. 6 is an engine control system. Schematic configuration diagram,
7 is a front view of the crank rotor and the crank angle sensor, FIG. 8 is a front view of the cam rotor and the cam angle sensor, FIG. 9 is a circuit configuration diagram of the electronic control system, and FIG. 10 is a fuel injection control at the time of starting and a fuel injection control at the time of normal operation. And FIG. 11 is a time chart of fuel injection.

In FIG. 6, reference numeral 1 indicates an engine,
In the figure, the cylinder block 1a is divided into two banks centering on the crankshaft 1b (the right bank in the figure is the left bank, the left side is the right bank), and the right bank is # 1.
A horizontally opposed four-cylinder engine in which # 3 cylinders are arranged and # 2 and # 4 cylinders are arranged in the left bank is shown. Cylinder heads 2 are provided on both left and right banks of a cylinder block 1a of the engine 1, and an intake port 2a and an exhaust port 2b are formed on each cylinder head 2.

An intake manifold 3 is communicated with the intake port 2a, a throttle chamber 5 is communicated with an upstream collecting portion of the intake manifold 3 through an air chamber 4, and an intake air is provided upstream of the throttle chamber 5. An air cleaner 7 is attached via a pipe 6.

Further, the air cleaner 7 of the intake pipe 6
A suction air amount sensor 8 of a hot wire type or a hot film type is interposed immediately downstream of the throttle chamber 5 and a throttle valve 5 a interposed in the throttle chamber 5.
And a throttle opening sensor 9 for detecting the throttle opening.
a and a throttle sensor 9 having a built-in idle switch 9b that is turned on when the throttle valve is fully closed.

Further, an idle speed control valve (ISCV) 11 for adjusting the amount of idle air is provided in a bypass passage 10 connecting the upstream side and the downstream side of the throttle valve 5a, and the intake manifold is provided. An intake pipe pressure / atmospheric pressure switching solenoid valve 12, which is turned on and off by an electronic control unit (ECU; see FIG. 9) described later, is provided in a passage communicating with the intake pipe pressure / atmospheric pressure switching solenoid. An absolute pressure sensor 13 is connected to the valve 12.

The intake pipe pressure / atmospheric pressure switching solenoid valve 12 comprises a solenoid three-way valve having a port communicating with the absolute pressure sensor 13, a port communicating with the intake manifold 3, and an atmospheric port. At the time of measurement, close the atmospheric port to the intake manifold 3
The absolute pressure sensor 1 by opening the port communicating with
Introducing the intake pipe pressure into 3, the atmospheric pressure is introduced into the absolute pressure sensor 13 by closing the port communicating with the intake manifold 3 and opening the atmospheric port when measuring the atmospheric pressure. ing.

Further, an injector 14 is provided immediately upstream of each intake port 2a of each cylinder of the intake manifold 3.
A spark plug 15a having a tip exposed to the combustion chamber is attached to the cylinder head 2 for each cylinder. An ignition coil 15b is connected to the ignition plug 15a, and an igniter 16 is connected to the ignition coil 15b.

The injector 14 is communicated with a fuel tank 18 via a fuel supply passage 17, and an in-tank type fuel pump 19 is provided in the fuel tank 18. The fuel from the fuel pump 19 is pumped from the injector 14 to the pressure regulator 21 via the fuel filter 20 interposed in the fuel supply passage 17, and the excess fuel is returned from the pressure regulator 21 to the fuel tank 18. The above injector 1
The fuel pressure to 4 is regulated to a predetermined pressure.

On the other hand, a knock sensor 22 is attached to the cylinder block 1a of the engine 1, and a water temperature sensor 24 is exposed to a cooling water passage 23 connecting the left and right banks of the cylinder block 1a. Also,
An O2 sensor 26 is exposed to the gathering portion of the exhaust manifold 25 communicating with the exhaust port 2b of the cylinder head 2, and a catalytic converter 27 is provided downstream of the O2 sensor 26.

A crank rotor 28 is mounted on a crank shaft 1b supported by the cylinder block 1a, and a crank angle sensor 29 is provided on the outer periphery of the crank rotor 28 so as to be opposed thereto. Further, a cam rotor 30 is connected to the cam shaft 1c of the cylinder head 2, and a cam angle sensor 31 for cylinder discrimination is provided opposite to the cam rotor 30.

As shown in FIG. 7, the crank rotor 28 has projections 28a, 28b and 28c formed on the outer periphery thereof, and these projections 28a, 28b and 28c are provided in the respective cylinders (# 1, # 2 and # 2). Before # 3, # 4 compression top dead center (BTD
C) It is formed at the positions of θ1, θ2, θ3. In this embodiment, θ1 = 97 ° CA, θ2 = 65 ° CA, θ3 = 1
0 ° CA.

Further, as shown in FIG. 8, on the outer periphery of the cam rotor 30, there are protrusions 30a, 30b, 3 for cylinder discrimination.
0c is formed, and the projection 30a is formed at the position θ4 after the compression top dead center (ATDC) of the # 3 and # 4 cylinders, and the projection 30b is formed.
Is composed of three protrusions and the first protrusion is the AT of the # 1 cylinder.
It is formed at the position of DCθ5. Further, the protrusion 30c
Is formed by two projections, and the first projection is the AT of the # 2 cylinder.
It is formed at the position of DC θ6. In this embodiment,
θ4 = 20 ° CA, θ5 = 5 ° CA, θ6 = 20 ° CA.

Then, as shown in the time chart of FIG. 11, each protrusion of the crank rotor 28 is detected by the crank angle sensor 29 including a magnetic sensor (electromagnetic pickup or the like), and θ1, θ2, θ3 (BTDC97).
°, 65 °, 10 °) crank pulse
While being output every two rotations (every 180 ° CA), each projection of the cam rotor 30 is detected by the cam angle sensor 31 which is also a magnetic sensor between the θ3 crank pulse and the θ1 crank pulse, and a predetermined number of them are detected. The cam pulse of is output.

An electronic control unit (ECU; see FIG. 9) 50, which will be described later, calculates the engine speed NE based on the input interval time of the crank pulse output from the crank angle sensor 29, and burns each cylinder. Based on the pattern of the order of strokes (for example, # 1 cylinder → # 3 cylinder → # 2 cylinder → # 4 cylinder) and the value obtained by counting the cam pulse from the cam angle sensor 31 by the counter, the fuel injection target cylinder and the ignition are performed. Cylinder discrimination of the target cylinder is performed.

Next, an electronic control unit (ECU) 50 for electronically controlling the engine 1 will be described with reference to FIG. The ECU 50 includes a main computer 51 that performs fuel injection control, ignition timing control, idle speed control, and the like, and a sub computer 52 dedicated to knock detection processing.
And a constant voltage circuit 53 for supplying stabilized power to each part, a drive circuit 54 and an A / D converter 55 connected to the main computer 51, and a sub computer 52. A / D
The converter 56, the A / D converter 56 has a frequency filter 5
Peripheral circuits such as an amplifier 58 connected via 7 are built in.

The constant voltage circuit 53 is connected to a battery 60 via a first relay contact of a power supply relay 59 having two relay contacts, and an anode of a diode 62 is connected to the battery 60 via an ignition switch 61. The sides are connected. The cathode side of the diode 62 is connected to one end of a relay coil of the power relay 59, and the other end of the relay coil is grounded.

Further, the constant voltage circuit 53 is connected to the battery 60 via the first relay contact of the power relay 59.
Is directly connected to the battery 60, and the ignition switch 61 is turned on.
When the relay contact of the power supply relay 59 is closed, power is supplied from the constant voltage circuit 53 to each part, while the constant voltage circuit 53 is always turned on regardless of whether the ignition switch 61 is ON or OFF. From this, backup power is supplied to a backup RAM 68 of the main computer 51 described later.

The fuel pump 19 is connected to the battery 60 via a relay contact of the fuel pump relay 63. The fuel pump relay 63 has a drive circuit 54 in which one end of the relay coil is connected to the battery 60 via the second relay contact of the power supply relay 59 and the other end of the relay coil is connected to the main computer 51. It is connected to the. A power supply line to each actuator extends from the second relay contact of the power supply relay 59.

The main computer 51 has a CPU 6
5, ROM66, RAM67, backup RAM6
8, a counter / timer group 69, a serial communication interface SCI 70, and an I / O interface 71 are microcomputers connected via a bus line 72, and the backup RAM 68 includes:
Backup power is constantly supplied from the constant voltage circuit 53 to retain data.

The counter / timer group 69 is used for various counters such as a free-run counter, a counter for counting input of cam angle sensor signals, a fuel injection timer, an ignition timer, and a periodic interrupt for generating a periodic interrupt. For convenience, various timers such as a timer, a timer for inputting a crank angle sensor signal, and a watchdog timer for monitoring a system abnormality are collectively referred to for convenience. In the main computer 51, various other software counters, A timer is used.

The input port of the I / O interface 71 has an idle switch 9b and a crank angle sensor 2
9, a cam angle sensor 31, a neutral switch 32 that is turned on when a shift lever of a transmission (not shown) is set to a neutral position, an air conditioner switch 33, a starter switch 34, and an ignition switch 61 are connected, and further, the above A / The intake air amount sensor 8, the throttle opening sensor 9a, the absolute pressure sensor 13, the water temperature sensor 24, the O2 sensor 26, and the vehicle speed sensor 35 are connected via the D converter 55, and the battery voltage VB
Is input and monitored.

An igniter 16 is connected to the output port of the I / O interface 71, and the ISCV 11, the intake pipe pressure / atmospheric pressure switching solenoid valve 12, the injector 14, and the fuel pump relay 6 are connected.
No. 3 relay coil is connected through the drive circuit 54, and the ignition switch 61 is turned on.
After the FF, the relay coil of the power supply relay 59 is connected to the drive circuit 54 on the cathode side of the diode 62 in order to realize the self-shut function of keeping the power supply relay 59 in the ON state for a predetermined time to secure the ECU power supply. Is connected to the output port of the I / O interface 71 via.

On the other hand, the sub computer 52, like the main computer 51, has a CPU 75 and a ROM 7.
6, RAM77, counter / timer group 78, SCI7
9, and the I / O interface 80 is the bus line 8
1 is a microcomputer connected through the main computer 51 and the sub computer 52.
Are connected to each other by a serial communication line via the SCIs 70 and 79.

A crank angle sensor 29 and a cam angle sensor 31 are connected to the input port of the I / O interface 80, and the knock sensor 22 is connected to the amplifier 5.
8, the frequency filter 57 and the A / D converter 56 are connected, and after the knock detection signal from the knock sensor 22 is amplified to a predetermined level by the amplifier 58,
A necessary frequency component is extracted by the frequency filter 57, converted into a digital signal by the A / D converter 56, and input.

I / O in the sub computer 52
The predetermined output port of the interface 80 is the I / O interface 7 in the main computer 51.
1 is connected to a predetermined input port, and the sub computer 52 determines whether or not knock has occurred based on a signal from the knock sensor 22, and outputs the determination result of whether or not knock has occurred to the I / O interface 80. The data is output to the main computer 51 via the port.

When a knock occurs, knock data transmitted from the sub computer 52 through the serial line is read into the main computer 51, and based on the knock data, the main computer 51.
The ignition timing of the cylinder is delayed to prevent knock.

That is, in the sub computer 52, a sample section of the signal from the knock sensor 22 is set based on the engine speed and the engine load, and the signal from the knock sensor 22 is quickly A / A in this sample section.
D-convert to faithfully convert the vibration waveform to digital data,
The presence or absence of knocking is determined based on this data, and the determination result is output to the main computer 51.

On the other hand, in the main computer 51,
According to the control program stored in the ROM 66, the CPU 65 processes detection signals from the sensors and switches input via the I / O interface 71, battery voltage, etc., and stores them in the RAM 67 and the backup RAM 68. Based on various data, fixed data stored in the ROM 66, etc., various control amounts such as the fuel injection amount, ignition timing, duty ratio of the drive signal to the ISCV 11 are calculated, and various actuators are driven to perform air-fuel ratio learning control, Various controls such as ignition timing control and idle speed control are performed.

That is, the fuel pump relay 63 is turned on by the drive circuit 54 to drive the fuel pump 19, and the intake pipe pressure / atmospheric pressure switching solenoid valve 12 is turned on.
When turned off, the absolute pressure sensor 13 alternately detects the atmospheric pressure and the intake pipe pressure, and outputs a drive pulse signal corresponding to the calculated fuel injection pulse width to the injector 14 of the corresponding cylinder at a predetermined timing to perform fuel injection. The ignition timing control is performed by outputting an ignition signal to the igniter 16 at a timing corresponding to the calculated ignition timing, and further, a duty control signal is output to the ISCV 11 to perform idle speed control and the like. .

In the main computer 51,
When the engine start mode associated with the ignition switch 61 being turned on is detected, before the start-up fuel injection amount by the normal start-up control is injected from the injector 14 in synchronization with the engine rotation associated with cranking, all The fuel injection amount for the initial explosion is injected asynchronously with the cylinders simultaneously, and the initial explosion can be easily obtained, and after the initial explosion, the complete explosion can be smoothly reached. That is, each function of the initial combustion fuel injection amount setting means, the starting fuel injection amount setting means, and the injection control means according to the present invention is performed by the main computer 51 and each sensor / actuator connected to the main computer 51. Is realized.

The air-fuel ratio control (fuel injection control) executed by the main computer 51 will be described below with reference to the flow charts shown in FIGS. Since the sub computer 52 is a computer dedicated to knock detection processing, description of its control content is omitted.

First, the ignition switch 61 is turned on.
When the ECU 50 is powered on, the system is initialized (clearing each flag and each variable value), and the startup all cylinders simultaneous injection setting routine shown in FIG. 2 is executed.

In the present embodiment, this start-up all-cylinder simultaneous injection setting routine is executed only once immediately after the system is powered on and the initialization is completed, and the driver turns on the ignition switch 61 and the engine is left as it is. Turn the starter switch 34 to O for cranking.
Even if the operation of setting to N is performed, the processing is terminated before the engine is actually cranked, and the processing of FIG.
It is determined whether or not to perform asynchronous injection for all cylinders simultaneously prior to the start-time injection in which the engine rotation is synchronized by the i (fuel injection pulse width that determines the fuel injection amount) setting routine.

That is, in this starting all cylinders simultaneous injection setting routine, first, in step S101, the backup R
By referring to the start-time all-cylinder simultaneous injection determination flag FST stored in AM68, the state at the previous engine start is determined. The all-cylinder simultaneous injection determination flag FST at the time of start is
It is cleared (FST ← 0) when the set time elapses (when the complete explosion state continues for the set time or longer) after the engine has completely exploded and the control at startup has changed to the control at normal time.
The state of the previous engine startup can be determined by the value of the all-cylinder simultaneous injection determination flag FST at startup.

Then, in the above step S101, FST =
When the engine has a history of not having a complete explosion at the last engine start, or having turned off the ignition switch 61 without performing cranking, the routine is ended as it is to avoid excessive supply of fuel, When FST = 0, the previous engine starting state has reached the complete explosion after the first explosion after the cranking, and if there is a history that the complete explosion state has continued for the set time or more, the process proceeds to step S102 and thereafter, and asynchronously for all cylinders simultaneously. Perform processing for performing injection.

That is, in step S102, the basic value TS is obtained based on the cooling water temperature TW detected by the water temperature sensor 24.
After setting TRT, the process proceeds to step S103, and the atmospheric pressure correction coefficient KTSATM for correcting the atmospheric pressure of the basic value TSTRT is set based on the atmospheric pressure ATM measured by the absolute pressure sensor 13.

The above basic value TSTRT is a fuel for correcting the amount of fuel that cannot be contributed to combustion by adhering to the intake manifold wall surface, the intake valve, the combustion chamber wall surface, etc. when the engine is started to obtain an air-fuel ratio suitable for the initial explosion. It is a base value for setting the amount (simultaneous injection pulse width TSSTRT for all cylinders at the time of starting, which will be described later), and is determined in advance by D-JETRO based on the intake pipe negative pressure at the time of extremely low rotation in the initial stage of cranking. As shown in step S102, the temperature value is set to a larger value as the cooling water temperature TW is lower.

Further, the atmospheric pressure correction coefficient KTSATM
As shown in step S103, the standard atmospheric pressure (7
Under 60 mmHg), KTSATM is set to 1.0, and the value is adjusted to a small value under high atmospheric pressure ATM such as in highlands to reduce the correction amount for the basic value TSTRT. Is set to a large value to increase the correction amount for the basic value TSTRT.

After that, the routine proceeds to step S104, where the voltage correction coefficient TCSL for compensating the invalid injection time of the injector 14 is set based on the battery voltage VB. The voltage correction coefficient TCSL is set to a larger value because the invalid injection time of the injector 14 is longer as the battery voltage VB is lower.

Then, the process proceeds to step S105, and the above step
The basic value TSTRT set in S102 is added to the above step S103.
At the start, the simultaneous injection pulse width TS for all cylinders is determined by multiplying the atmospheric pressure correction coefficient KTSATM set in step S4 and the voltage correction coefficient TCSL set in step S104 to determine the fuel injection amount for initial combustion.
Set STRT (TSSTRT ← TSTRT × KTS
ATM × TCSL), the process proceeds to step S106.

In step S106, the all-cylinder simultaneous injection pulse width TSSTRT at startup set in step S105 is set, and in step S107, the injectors 14 of all cylinders are simultaneously driven via the drive circuit 54. And step
In S108, the all-cylinder simultaneous injection determination flag at start is set (F
ST ← 1), end the routine.

As a result, a fuel amount corresponding to the simultaneous injection pulse width TSSTRT of all cylinders at the time of starting is simultaneously injected into all cylinders, and this fuel is first sucked into the cylinders during the intake stroke during cranking, so that the first explosion occurs. The air-fuel ratio is suitable for, and the initial explosion can be easily obtained.

Subsequent to the starting all cylinders simultaneous injection setting routine described above, the Ti setting routine shown in FIGS. 3 to 5 is executed at predetermined intervals until the engine speed exceeds the complete explosion determination speed. The starting fuel injection amount for obtaining the proper air-fuel ratio from the initial explosion to the complete explosion is set in the startup control. In this routine, first, in step S201, it is checked whether or not the cylinder discrimination based on the signal from the crank angle sensor 29 and the signal from the cam angle sensor 31 is completed.

In this cylinder discrimination, it is discriminated whether the crank pulse input from the crank angle sensor 29 corresponds to a crank angle of θ1, θ2 or θ3 based on the cam pulse input pattern from the cam angle sensor 31. The cylinder for fuel injection is discriminated from the input patterns of the crank pulse and the cam pulse.

That is, as shown in the time chart of FIG. 11, for example, if there is a cam pulse input between the previous crank pulse input and the current crank pulse input, the current crank pulse is θ1 crank. It can be identified as a pulse, and the crank pulse to be input next time can be identified as a θ2 crank pulse.

Further, when there is no cam pulse input between the crank pulse inputs of the previous time and this time, and there is a cam pulse input between the crank pulse inputs of the time before two times and the previous time, the current crank pulse can be identified as a θ2 crank pulse, and the next input The generated crank pulse can be identified as a θ3 crank pulse. In addition, when there is no cam pulse input between the previous time and this time, and between the crank pulse input two times before and the previous time, the crank pulse input this time can be identified as the θ3 crank pulse, and the crank pulse input next time is It can be identified as θ1 crank pulse.

Further, three cam pulses are input between the crank pulse input of the previous time and the crank pulse input of the present time (θ corresponding to the protrusion 30b).
5 cam pulses), the next compression top dead center is the # 3 cylinder, and when two cam pulses are input (θ6 cam pulse corresponding to the protrusion 30c) between the crank pulse inputs of the previous time and this time, It can be determined that the compression top dead center is the # 4 cylinder.

Further, one cam pulse is input between the crank pulse input at the previous time and the crank pulse input at this time (θ4 corresponding to the protrusion 30a).
Cam pulse), and when the previous compression top dead center determination is the # 4 cylinder, the next compression top dead center is the # 1 cylinder, and similarly, one cam pulse is input between the crank pulse input between the previous time and this time. If it is input and the previous compression top dead center determination is the # 3 cylinder, it can be determined that the next compression top dead center is the # 2 cylinder.

When the cylinder cannot be discriminated, the routine exits from step S201. When the cylinder can be discriminated, the routine proceeds from step S201 to step S202.
Based on the engine speed NE calculated based on the signal from the crank angle sensor 29 and the intake air amount Q based on the signal from the intake air amount sensor 8, the basic fuel injection pulse width TP
Is calculated (TP ← K × Q / NE; where K is an injector characteristic correction constant).

Next, in step S203, the operating state of the starter switch (starter SW) 34 is detected and turned on.
When (starting), in step S204, the start increase coefficient KST for increasing the fuel only at the start during the starter motor operation is set to the set value CKS in order to improve the engine startability.
When T (however, CKST> 1.0) is set, when it is OFF, in step S205 the starting amount increase coefficient KST is set to 1.0 (no starting amount increase correction), and the flow proceeds to step S206.

In step S206, the mixture ratio allocation coefficient KMR is set based on the basic fuel injection pulse width TP and the engine speed NE. The mixing ratio allocation coefficient KMR is a coefficient for ensuring fine controllability even when there is a deviation with respect to the characteristics peculiar to the injector 14 and the intake air amount sensor 8, and is a basic value representing the engine load. In order to obtain an appropriate air-fuel ratio for each region of the engine operating state specified by the fuel injection pulse width TP and the engine speed NE,
For example, the optimum coefficient obtained in advance by experiments or the like is stored in a table or the like.

After that, the routine proceeds to step S207, where a full increase coefficient KFULL is set based on the throttle opening Th detected by the throttle opening sensor 9a, the basic fuel injection pulse width TP, and the engine speed NE. This full increase coefficient KFULL is used when the throttle valve is fully opened or when the load is high.
It is an increase correction coefficient for increasing the amount of fuel to improve the output performance in an operating state where output is required. When the throttle opening Th indicates that the throttle valve is fully opened, or when the basic fuel injection pulse width TP is high load. When indicating the state, it is set by referring to a preset table based on the engine speed NE with interpolation calculation. When the throttle opening Th is other than full open and the engine load is other than high load, KFULL ← 0 is set.

Next, the process proceeds to step S208, where the water temperature increase coefficient KTW for increasing the fuel injection amount and correcting the fuel injection amount to secure the drivability in the engine cold state is set based on the cooling water temperature TW representing the engine temperature. In S209, the post-starting increase coefficient KAS for ensuring the stability of the engine speed immediately after the engine is started is also set based on the cooling water temperature TW that also represents the engine temperature.

As shown in step S208, the water temperature increasing coefficient KTW is set so that the fuel increasing rate increases as the cooling water temperature TW, that is, the engine temperature decreases.
Further, the post-startup increase coefficient KAS is set to an initial value when the starter switch 34 is ON, as shown in step S209, and the starter switch 34 is turned ON → OFF.
Thereafter, the set value is decreased each time the routine is executed until it becomes zero.

In the following step S210, the post-idle amount increase coefficient KAI for preventing the rattling at the time of releasing the idle is set. The post-idle increase coefficient KAI is set to an initial value based on the cooling water temperature TW when the vehicle speed is equal to or lower than the set vehicle speed and when the throttle valve is fully closed to open, and thereafter, as shown in step S210, routine execution is performed. Every time, it is decreased by the set value until it becomes zero.

Then, the process proceeds to step S211, and various increase factors COEF summarizing the above respective factors are calculated (CO
EF ← KST × (1 + KMR + KFULL + KTW + KAS + KA
I)), in step S212, the air-fuel ratio feedback correction coefficient α for making the air-fuel ratio close to the target air-fuel ratio is set based on the output voltage of the O2 sensor 26, and the intake air amount measuring system such as the intake air amount sensor 8 and A learning correction coefficient KBL for promptly correcting a variation in the fuel supply system such as the injector 14 during production or a shift in the air-fuel ratio due to a change over time.
Set RC and proceed to step S213.

In step S213, the basic fuel injection pulse width TP is corrected by the above-mentioned various increase factors COEF, the air-fuel ratio feedback correction factor α, and the learning correction factor KBLRC,
Effective injection pulse width Te suitable for one cylinder, one rotation and one injection
Is calculated (Te ← TP × α × COEF × KBLRC).

After that, the routine proceeds to step S214, and the normal time control discrimination flag F1 (initial value is 0: start time control) for discriminating between the normal time control and the start time control is referred to, and F1 =
If it is 0, and the starting control is selected when the previous routine is executed, the process proceeds to step S215, it is determined whether or not the engine has completely exploded, and the reference value is used when switching from the starting control to the normal control. Update the complete explosion determination rotation speed NST with a preset value NST1 (for example, 500 rpm),
If F1 = 1 and the normal control was selected during the previous routine execution, the process branches to step S216 to set the complete explosion determination rotation speed NST to the set value NST2 (where NST1> NST
2, update at, for example, 300 rpm, and proceed to step S217.

The normal-time control determination flag F1 is set in step S219, which will be described later, during normal-time control, and is cleared in step S233, which will be described later, during start-up control. In this way, by providing the hysteresis for the complete explosion determination rotation speed NST, as shown in FIG. 10, control hunting at the time of shifting from the starting fuel injection control to the normal fuel injection control is prevented.

Next, at step 217, the engine rotational speed NE is compared with the complete explosion determination rotational speed NST, and when NE> NST, normal-time fuel injection control is executed.
Proceed to S218 and subsequent steps, and if NE ≦ NST, proceed to step S223.
After that, the process branches to execute the fuel injection control at startup.

In the following description, the fuel injection control at the start will be described first, and then the fuel injection control at the normal time will be described.

When the process branches from step S217 to step S223, the voltage correction pulse width TS set based on the battery voltage VB for correcting the invalid injection time of the injector 14 is added to the effective injection pulse width Te set in step S213. Is added to calculate the starting injection pulse width Ti0 (Ti0 ← Te + TS), and the basic value table TCST is set with reference to the basic value table TBLCST with interpolation calculation based on the cooling water temperature TW in step S224. This basic value TCST is a base value for calculating the cold start pulse width TiST at the time of starting, and as shown in step S224, it is set to a larger value as the cooling water temperature TW is lower.

In the following step S225, the engine speed N
Based on E, the rotation correction coefficient TCSN is set by referring to a table or the like, and the time correction coefficient TKCS is set in step S226.
As shown in step S226, when the starter switch 34 is turned on, the time correction coefficient TKCS is fixed at TKCS = 1.0 for a predetermined time, and then gradually decreases until it becomes zero. . Therefore, the starter switch 34
If the startup injection control is not completed within a predetermined time after turning ON, the cold start pulse width TiST set in step S229 described later gradually decreases, and finally TiST = 0.
Becomes

Next, at step S227, the voltage correction coefficient TCSL for compensating the invalid injection time of the injector 14 is set based on the battery voltage VB by referring to a table or the like. Then, at step S228, the throttle opening is calculated based on the throttle opening Th. The correction coefficient TCSA is set by referring to a table or the like. This throttle opening correction coefficient TCSA is set to a larger value for increasing correction as the throttle opening Th increases.

Further, in step S229, the basic value TCST set in step S224 is set to the correction coefficient TCS.
When the cold start pulse width TiST is calculated by correcting with N, TKCS, TCSL, TCSA (TiST ← TCST × TCSN × T
KCS × TCSL × TCSA), in step S230, the cold start pulse width TiST is compared with the starting injection pulse width Ti0 calculated in step S223, and the larger one is adopted as the final fuel injection pulse width Ti. Therefore, from the cold start pulse width TiST to the starting injection pulse width Ti
The connection of the fuel injection amount by O is smoothed, the sudden change of the fuel injection amount is prevented, the sudden change of the air-fuel ratio is suppressed, and the deterioration of the engine drivability and the engine stall accompanying the sudden change of the air-fuel ratio are prevented.

That is, when Ti0 ≧ TiST, the routine proceeds from step S230 to step S231 where the starting injection pulse width Ti0 is set as the fuel injection pulse width Ti which determines the starting fuel injection amount, and when TiO <TiST, After proceeding from step S230 to step S232 and setting the cold start pulse width TiST as the fuel injection pulse width Ti that determines the starting fuel injection amount, the routine proceeds to step S231 or step S232 to step S233 to determine the normal-time control. The flag F1 is cleared (F1 ← 0), the process proceeds to step S222, the fuel injection pulse width Ti is set, and the routine exits.

In this fuel injection control at the time of starting, FIG.
As shown in 1, the start set in step S222 is performed for each injector 14 having two cylinders as one group (for example, a group of # 1 cylinder and # 2 cylinder, a group of # 3 cylinder and # 4 cylinder). The fuel injection pulse width Ti at the time is output as a drive pulse signal for each revolution of the engine.
Group injection is performed for each cylinder.

That is, the above-mentioned simultaneous injection pulse width TSSTRT for all cylinders at the time of start-up provides a rich air-fuel ratio that makes it easy to obtain an initial explosion only at the first combustion at engine startup, and after the initial explosion, a fuel injection for smoothly shifting to a complete explosion. As a quantity, in order to prevent overrich of the air-fuel ratio, the spark plug 15
It is possible to prevent engine stall and rotation fluctuation without causing fogging or smoldering on a.

Eventually, the engine speed NE increases and NE
When> NST, it is determined in step S217 that the engine is in the complete explosion state, and the routine proceeds from step S217 to step S218 to perform the normal fuel injection control.

In this normal-time fuel injection control, the voltage correction pulse width TS for compensating the invalid injection time of the injector 14 is added to the value obtained by doubling the effective injection pulse width Te,
Set the fuel injection pulse width Ti (Ti ← 2 × Te + T
S). That is, in normal-time fuel injection control, sequential injection (injection for each cylinder once every two revolutions of the engine)
2 to the group injection by the fuel injection control at the time of startup (injection of two cylinders once per engine revolution).
Double the amount of fuel (2 × Te) is required.

After that, if the process proceeds to step S219 and the normal time control determination flag F1 is set (F1 ← 1), step S
At 220, it is checked whether or not the set time has passed after the control at the time of starting was changed to the control at the normal time. Therefore, until the set time elapses after shifting to the normal fuel injection control, the above-mentioned start-time all-cylinder simultaneous injection determination flag FST is maintained in the set state (FST = 1), and the engine is stopped in this state. Then, at the next start, FST =
By 1, the asynchronous start-up all cylinders simultaneous injection in the start-up all cylinders simultaneous injection setting routine (see FIG. 2) is canceled. Further, when the set time has elapsed after shifting to the normal time control, the process proceeds to step S221 so that the simultaneous injection at all cylinders at startup is performed at the next engine start, and the startup all cylinders simultaneous injection determination flag FST of the backup RAM 68 is started. Is cleared (FST ← 0), and the process proceeds to step S222. Then, in step S222, the fuel injection pulse width Ti set in step S218 is set and the routine exits.

In the normal fuel injection control, the fuel injection pulse width Ti set in step S222 is output as a drive pulse signal to the injector 14 of the fuel injection target cylinder at a predetermined timing, and the injector 14 measures the fuel in a predetermined amount. The injected fuel is injected.

In this embodiment, the fuel injection amount for obtaining the air-fuel ratio suitable for the initial explosion, that is, the fuel corresponding to the starting all cylinders simultaneous injection pulse width TSSTRT is injected only once before the engine cranking. However, the injection may be divided into several times before the completion of the cylinder discrimination at the engine start.

FIG. 12 and FIG. 13 are flowcharts of a starting all cylinders simultaneous injection setting routine according to the second embodiment of the present invention.

In this embodiment, before the cylinder discrimination based on the signals from the crank angle sensor 29 and the cam angle sensor 31 at the time of engine start is completed, when the set number of crank pulses are input from the crank angle sensor 29, Depending on the state at the time of starting the engine, FIG.
Prior to the normal start-up injection synchronized with the engine rotation by the Ti setting routine of FIG. 5, it is determined whether or not the start-up all-cylinder simultaneous injection is executed.

The start-up all cylinders simultaneous injection setting routine of this embodiment is shown in FIG. 12 and FIG. 13. When the engine is cranked after the system is initialized by turning on the ignition switch 61, the crank rotor 28 is rotated. This is executed every time the crank pulse output from the crank angle sensor 29 is input.

In this routine, first, it is checked whether or not the cylinder discrimination is completed in step S301. If the cylinder discrimination is not completed, the routine is exited. If the cylinder discrimination is completed, the routine proceeds to step S302. Next, the backup RAM 68 is started and all cylinders simultaneous injection determination flag FST is started.
Check the state at the last engine start by referring to.

When FST = 1, step S302 is executed.
When FST = 0, the routine proceeds from step S302 to step S303 to set the pulse input number setting value ns based on the cooling water temperature TW by referring to a table or the like.
This pulse input frequency setting value ns has a low cranking rotation speed and a large rotation fluctuation at a low water temperature. Therefore, in consideration of an erroneous crank pulse input and a cylinder delay determination step,
As shown in S303, it is set to be large at low water temperature and small at high water temperature.

Next, in step S304, when the count value C for counting the number of crank pulse inputs is counted up (C ← C + 1), it is determined in step S305 whether the count value C has reached the pulse input count set value ns. If C <ns, the routine is exited. If C ≧ ns, the routine proceeds to step S306, where the basic value TSTRT, which is the base value of the starting all cylinders simultaneous injection pulse width TSSTRT, is set based on the cooling water temperature TW. , And further, step S307
Then, based on the atmospheric pressure ATM, the atmospheric pressure correction coefficient KTSATM for correcting the basic value TSTRT to the atmospheric pressure is set.

After that, the process proceeds to step S308, and the correction coefficient KTSNS is set based on the pulse input number setting value ns. As shown in step S308, this correction coefficient KTSNS is set to KTSNS = 1 (when the first crank pulse is input, the simultaneous injection is performed in all cylinders) when n s = 0, and the pulse input count set value ns is increased. As a result, the asynchronous starting injection amount is gradually decreased, and, for example, when ns = 5, KTSNS = 0 (at the time of high water temperature, there is no simultaneous injection at all cylinders at the time of starting).

In the following step S309, the battery voltage VB
The voltage correction coefficient TCSL for compensating for the invalid injection time of the injector 14 which varies depending on
The atmospheric pressure correction coefficient KTSA is added to the basic value TSTRT.
TM, the correction coefficient KTSNS, and the voltage correction coefficient TCSL are multiplied to each other to simultaneously start up all-cylinder simultaneous injection pulse width TS
If STRT is set (TSSTRT ← TSTRT × K
TSATM x KTSNS x TCSL), in step S311,
At the time of starting, the all-cylinder simultaneous injection pulse width TSSTRT is set.

When the injectors 14 of all the cylinders are simultaneously driven through the drive circuit 54 in step S312, the count value C is cleared (C ← 0) in step S313, and then in step S314, the normal startup control is performed. Set the simultaneous injection discrimination flag for all cylinders at startup to shift to (FST ←
1) Exit the routine.

Also in this embodiment, as in the case of the first embodiment described above, the rich air-fuel ratio which makes it easy to obtain the initial explosion only at the first combustion at the engine start, and the fuel injection amount for smoothly shifting to the complete explosion after the initial explosion. As a result, it is possible to prevent the air-fuel ratio from over-riching, but just before the start of normal start-up control after cylinder discrimination is completed, the number of crank pulse inputs is adjusted so that all cylinders are simultaneously injected depending on the engine state. The fine adjustment can be performed, and the fuel effective for the initial combustion can be surely supplied to eliminate unnecessary fuel consumption.

14 to 17 relate to the third embodiment of the present invention, FIGS. 14 to 16 are partial flowcharts of the Ti setting routine, and FIG. 17 is a flowchart of the initial explosion correction execution count routine.

This embodiment ensures the air-fuel ratio required for the initial explosion by executing the combustion injection in all cylinders simultaneously before the start-up injection in which the above-mentioned first and second embodiments are normally synchronized with the engine rotation. On the other hand, the correction for increasing the fuel amount for the initial explosion is added at the time of normal injection at the time of engine rotation-synchronous injection.

That is, this embodiment is the same as the T in the first embodiment.
A part of the processing of the i setting routine is modified as shown in FIGS. 14 to 16, and the main computer 51 causes the starting fuel injection amount setting means, the initial explosion fuel injection correction amount setting means,
This embodiment realizes an injection control means, and hereinafter, a part different from the first embodiment in processing will be described.

In the Ti setting routine of the present embodiment, the same processing as in the first embodiment is performed through steps S201 to S217, and the comparison result of the engine speed NE and the complete explosion determination rotation speed NST in step S217 is NE ≤ NST. When shifting to the fuel injection control at the time of starting after S223, as shown in FIG. 15 and FIG. 16, steps S223 to S228 of the same processing as the first embodiment are performed.
Through the basic value TCST, each correction coefficient TCSN, TKCS, TCSL,
When TCSA is set, the process proceeds from step S228 to step S2211, and the complete explosion injection pulse width TSTRTA (corresponding to the cold start pulse width TiST in the first mode) is calculated (TSTRTA ← TCST × TCSN × TKCS × TCSL × TCS).
A), in step S2212, the correction additional pulse basic value TSTRTADD is set by referring to a table or the like based on the cooling water temperature TW.

The corrected additional pulse basic value TSTRTAD
As will be described later, D is a base value for calculating a correction pulse width for initial combustion TSTRTB for correcting the injection pulse width for complete combustion TSTRTA so as to match the air-fuel ratio for obtaining the initial combustion, and step S2212 As shown in the figure, the lower the cooling water temperature TW, the larger the value is set.

Next, from step S2212 to step S22.
Proceeding to step 13, when the atmospheric pressure correction coefficient KTSATM for correcting the basic value TSTRTADD with the atmospheric pressure is set, the correction coefficient KTSNS is set in step S2214. This correction coefficient KTSNS is for correcting the basic value TSTRTADD according to the number of crank pulse inputs determined by the cooling water temperature TW, and is the same as the correction coefficient KTSNS in the second embodiment described above, but the cooling water temperature T
It may be set directly by W.

In the following step S2215, the correction coefficient KTSNINJ is set based on the additional correction execution count ninj of the initial explosion fuel increase correction that is counted up for each initial explosion increase correction. The correction coefficient KTSNINJ is a coefficient for correcting the initial explosion correction pulse width TSTRTB for each injection of the initial explosion increase correction, and the correction coefficient KTSNINJ is set in step S2.
As shown in 215, the initial value is 1, and finally KTSNINJ = 0 (without initial fuel increase correction).

Here, the additional correction execution count ninj is
The count is incremented for each fuel injection by the initial explosion correction execution count routine shown in FIG. 17. In this routine, the normal control discrimination flag F1 is referred to in step S401, and the routine exits during normal control with F1 = 1.
When the control is performed at the time of starting with F1 = 0, the process proceeds to step S402, and when the additional correction execution number ninj is counted up (ninj ←
ninj + 1), store in the backup RAM 68 and exit the routine.

That is, in consideration of the case where the engine is restarted without a complete explosion at the current start, the additional correction execution count ninj is stored in the backup RAM 68.
The value of the correction coefficient KTSNINJ used first at restart is made small, and the amount of increase correction for initial explosion is made small to prevent the air-fuel ratio overrich at the time of restart.

In step S2215, the correction coefficient KTSNI
When NJ is set, the process proceeds to step S2216, and the correction additional pulse basic value TSTR set in step S2212 is set.
Each correction coefficient KTSATM, KTSNS, KT is added to TADD.
SNINJ and voltage correction coefficient TCSL are multiplied to determine the fuel injection correction amount for start-up.
Calculate TB (TSTRTB ← TSTRTADD × KT
SATM x KTSNS x KTSNINJ x TCSL), in step S2217, the correction pulse width TSTRTB for this initial explosion
Is added to the complete explosion injection pulse width TSTRTA to calculate the cold start pulse width TiST (TiST ← TSTRT
A + TSTRTB).

Then, in step S2218, the cold start pulse width TiST is compared with the starting injection pulse width Ti0 (calculated in step S223) as in the first embodiment, and the larger one is finally determined in step S2219 or step S2220. The fuel injection pulse width Ti is set as appropriate, and the routine proceeds to step S222 to set the fuel injection pulse width Ti and exit the routine.

Then, the engine speed NE increases and NE
> NST is reached, and it is judged that the engine has completely exploded
When the control shifts from S217 to the normal time control, the same steps S218 and S219 as those in the first embodiment are performed, and then in step S220, it is checked whether or not the set time has elapsed after the control at the start time is changed to the normal time control, and the normal time control is performed. After the transition, if the set time has not elapsed, the process jumps to step S222. Therefore, the counted number of additional correction executions ninj is maintained as it is until the set time elapses after shifting to the normal fuel injection control, and the engine is stopped before the set time elapses. At the time, the above-mentioned correction coefficient KTSNINJ
Is set to a smaller value in the additional correction execution count ninj, the initial combustion increase correction amount is decreased, and overrich at restart is prevented. Further, when the set time has elapsed after shifting to the normal time control, in order to perform the initial combustion increase correction as usual at the next engine start, step S2
In step 210, the backup RAM 68 is cleared of the additional correction execution count ninj (ninj ← 0), and the flow advances to step S222. Then, in step S222, the fuel injection pulse width Ti set in step S218 is set and the routine exits.

In this embodiment as well, similar to the first and second embodiments described above, it is possible to easily obtain the initial explosion and smoothly shift from the initial explosion to the complete explosion. After the determination is completed, the injection amount at startup is corrected to match the air-fuel ratio for obtaining the initial explosion, and the correction amount is attenuated each time the injection is performed, so the fuel supplied to the engine is burned. Can be effectively applied to, and it is possible to further reduce wasteful fuel consumption at the time of starting,
Efficiency can be improved.

[0113]

As described above, according to the present invention, the amount of fuel that adheres to the intake manifold wall surface, the intake valve, the combustion chamber wall surface and the like and cannot contribute to combustion is corrected in the initial stage of starting control. In order to prevent the air-fuel ratio from over-riching by shortening the time until the first explosion and not supplying excessive fuel after the initial explosion, without causing spark plug fogging or smoldering, engine stall or Rotational fluctuations can be prevented, the engine can be started reliably, and the exhaust emission at the start can be improved.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of the present invention.

FIG. 2 is a flowchart of a starting all-cylinder simultaneous injection setting routine according to the first embodiment of the present invention.

FIG. 3 is a flowchart of the Ti setting routine (part 1).

FIG. 4 is a flowchart of the Ti setting routine (part 2).

FIG. 5 is a flowchart of the Ti setting routine (part 3).

FIG. 6 is a schematic configuration diagram of an engine control system of the above.

FIG. 7 is a front view of a crank rotor and a crank angle sensor.

FIG. 8 is a front view of a cam rotor and a cam angle sensor as above.

FIG. 9 is a circuit configuration diagram of an electronic control system according to the first embodiment;

FIG. 10 is an explanatory diagram showing a switching state between startup fuel injection control and normal fuel injection control.

FIG. 11: Same as above, fuel injection time chart

FIG. 12 is a flowchart (part 1) of a starting all cylinders simultaneous injection setting routine according to the second embodiment of the present invention.

FIG. 13 is a flowchart of a simultaneous injection setting routine for all cylinders at startup (part 2).

FIG. 14 is a partial flowchart of a Ti setting routine according to the third embodiment of the present invention.

FIG. 15 is the same as the above, but is a partial flowchart of the Ti setting routine.

FIG. 16 is a partial flowchart of the Ti setting routine of the above.

FIG. 17 is a flowchart of a routine for counting the number of times of initial explosion correction execution, same as above

[Explanation of symbols]

1 ... Engine 51 ... Main computer (fuel injection amount setting means for initial explosion, fuel injection amount setting means for starting, fuel injection correction amount setting means for initial explosion, injection control means) NE ... Engine speed NST ... Complete explosion determination rotation Number TSSTRT ... Simultaneous injection pulse width for all cylinders at startup (fuel injection amount for initial explosion) TSTRTB ... Correction pulse width for initial explosion (fuel injection correction amount for initial explosion)

Claims (4)

[Claims] 1. A first-injection fuel injection amount setting means for setting an initial-injection fuel injection amount for obtaining an air-fuel ratio suitable for an initial explosion at the time of engine start, and an initial-to-complete explosion. The starting fuel injection amount setting means for setting the starting fuel injection amount for obtaining an appropriate air-fuel ratio according to the engine state, and the initial explosion fuel injection amount set by the initial explosion fuel injection amount setting means Injection is performed asynchronously with the engine rotation before the completion of cylinder discrimination at the time of starting, and after completion of cylinder discrimination, the starting fuel injection amount set by the starting fuel injection amount setting means is set to a complete explosion in which the engine speed is preset. A fuel injection control device for an engine, comprising: an injection control means for injecting fuel in synchronism with engine rotation until the number of rotations exceeds a judgment rotational speed. 2. An initial explosion fuel injection amount setting means for setting an initial explosion fuel injection amount for obtaining an air-fuel ratio suitable for the initial explosion at engine startup, and from initial explosion to complete explosion. The starting fuel injection amount setting means for setting the starting fuel injection amount for obtaining an appropriate air-fuel ratio according to the engine state, and the crank angle signal is input the set number of times before the cylinder discrimination at the engine start is completed. At this time, the initial explosion fuel injection amount set by the initial explosion fuel injection amount setting means is injected, and after the cylinder discrimination is completed, the starting fuel injection amount set by the starting fuel injection amount setting means is set to the engine speed. And an injection control means for injecting the fuel until the engine exceeds a preset complete explosion determination rotation speed. 3. A starting fuel injection amount setting means for setting a starting fuel injection amount for obtaining an appropriate air-fuel ratio from initial explosion to complete explosion at the time of engine startup, and for obtaining the initial explosion. A fuel injection correction amount for initial explosion for correcting the fuel injection amount for start-up to match the air-fuel ratio is set according to the engine state, and this fuel injection correction amount for initial explosion is attenuated according to the fuel injection history. The initial combustion fuel injection correction amount setting means and the initial combustion fuel set to the starting fuel injection quantity set by the starting fuel injection quantity setting means until the engine speed exceeds a preset complete combustion judgment rotation speed. A fuel injection control device for an engine, comprising: an injection control unit for adding and injecting a fuel injection correction amount for initial explosion set by an injection correction amount setting unit. 4. The injection control means injects the fuel injection amount for initial explosion only when there is a history of complete explosion when the engine was started last time. Engine fuel injection control device.