JPH04325751A - Fuel injection control device for engine - Google Patents

Abstract

PURPOSE:To reduce output difference between the totally closed time and open time of a throttle valve so as to suppress the vibration of a vehicle by delaying fuel cut-off control action at the time of being in a low-speed and low-rotation region, and performing idle speed control until the start of fuel cut-off control. CONSTITUTION:The operating state of an engine 2 is detected by a throttle sensor 24, a vehicle speed sensor, an engine speed sensor 26 and an intake pipe pressure sensor 28. These signals are inputted into a control part 22 so as to delay fuel cut-off control action only for the specified time in the case of satisfying fuel cut-off control conditions at the time of being in a low-speed and low-rotation region. An ISC control valve 32 and an ignition coil 30 are also controlled in such a way as to perform idle speed control of increasing by-pass air quantity and spark-advancing the ignition timing until the start of fuel cut-off control.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection control system for an engine, and more particularly to a fuel injection control system for an engine that performs fuel cut control in a low vehicle speed range and low rotation range.

0002

2. Description of the Related Art Some vehicle engines are equipped with a fuel injection amount control device as a countermeasure to problems such as harmful exhaust components and fuel consumption rate. This fuel injection amount control device controls the operation of the injector by inputting changes in engine operating conditions such as engine load, engine speed, cooling water temperature, and intake air amount as electrical signals.

By the way, some engine fuel injection control devices employ idle speed control (ISC) control.
In the control, a solenoid valve for idle speed control is provided in the middle of a bypass passage that bypasses the throttle valve, and the amount of bypass air is controlled by opening and closing this solenoid valve.

[0004] Furthermore, as a fuel injection control device for an engine, there is one disclosed in Japanese Patent Publication No. 42099/1983. The fuel cut control method disclosed in this publication sets the engine speed as a condition for starting and ending a fuel cut to a larger value as the gear shifts to a lower speed side, and The delay time from the time when the engine reaches the engine speed to the time when fuel cut starts is set to a larger value as the gear shifts to the lower speed side, without impeding good drivability. , fuel consumption rate and emissions of unburned components are suppressed.

Furthermore, there is one disclosed in Japanese Patent Application Laid-Open No. 2-19633. The engine ignition timing control device disclosed in this publication controls the ignition timing during the fuel cut delay time during engine deceleration operation, prevents the discharge of unburned gas, and purifies exhaust gas. , suppresses sudden fluctuations in engine torque and prevents vehicle body vibration during deceleration.

[0006]

[Problems to be Solved by the Invention] However, conventional fuel injection control devices for engines do not operate in a manner that slowly opens and closes the throttle valve when the vehicle speed is below 20〓/h and/or when the engine speed is below about 2500 rpm. In the case of driving conditions such as traffic jams, there is a decrease in output when the throttle valve is fully closed and fuel cut control is performed, and an increase in output when the throttle valve is opened and normal fuel injection is activated. The difference in output caused the vehicle to vibrate in the front-rear direction, resulting in a significant deterioration in riding comfort.

[0007] As a measure to eliminate this drawback, the vehicle speed is
There is a system that controls the fuel cut control so as not to operate when the operating condition is that the engine speed is less than 0/h or the engine speed is about 2500 rpm or less.

[0008] Generally, in a passenger car, it is desirable to operate fuel cut control in a low vehicle speed and low rotation range for the purpose of saving fuel and protecting the catalyst.

However, under the above-mentioned predetermined operating conditions,
Even in those that do not activate fuel cut control,
There remains a difference in output between when the throttle valve is fully closed and when it is opened.
There are disadvantages in that the vibration of the vehicle cannot be completely suppressed, the riding feeling deteriorates, and this is disadvantageous in practical terms.

0010

[Means for Solving the Problems] Therefore, in order to eliminate the above-mentioned disadvantages, the present invention provides a fuel injection control device for an engine that controls a fuel injection amount according to the operating state of the engine, in which a throttle valve provided in the engine is provided. A throttle sensor is provided to detect the opening degree of the engine, a vehicle speed sensor is provided to detect the speed of the vehicle equipped with the engine, and a rotation speed sensor is provided to detect the rotation speed of the engine. When the fuel cut control conditions are satisfied in the vehicle speed range and low rotation range, the fuel cut control operation is delayed by a predetermined time, and the amount of bypass air is increased and the ignition timing is advanced until the fuel cut control is started. The present invention is characterized in that a control section is provided to perform idle speed control.

[0011]

[Operation] With the invention as described above, when the fuel cut control conditions are satisfied in the low vehicle speed range and low rotation range, the control section delays the fuel cut control operation by a predetermined period of time, and this fuel cut control is The idle speed control is performed by increasing the amount of bypass air and advancing the ignition timing until the engine starts, reducing the difference in output between when the throttle valve is fully closed and when it is fully open, and suppressing vehicle vibration. ing.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 and 2 show an embodiment of the present invention. In FIG. 2, 2 is an engine, 4 is an intake passage,
6 is an exhaust passage.

A throttle valve 8 is provided in the intake passage 4 of the engine 2, and an injector 10 is provided in the intake passage 4 downstream of the throttle valve 8. Fuel injected from the injector 10 is drawn into a combustion chamber (not shown) together with air and is combusted. After combustion, the exhaust gas produced by combustion is discharged to the outside through the exhaust passage 6.

The injector 10 has a fuel supply passage 1
2 communicates with the fuel tank 14. The fuel in the fuel tank 14 is supplied to the injector 10 via the fuel supply passage 12 by a fuel pump 16.

Further, a fuel regulator 18 is provided in the fuel supply passage 12, and the fuel regulator 18 supplies fuel by introducing intake pressure through a pressure guiding passage 20, one end of which communicates with the intake passage 4 on the downstream side of the throttle valve 8. This is to adjust the pressure to a predetermined pressure.

The injector 10 is connected to a control section 22, and the control section 22 includes the throttle valve 8.
a throttle sensor 24 that detects the opening of the engine 2;
A vehicle speed sensor (not shown) that detects the speed of a vehicle (not shown) equipped with the engine, a rotation speed sensor 26 that detects the engine speed, and an intake pipe pressure of the intake passage 4 downstream of the throttle valve 8. A pressure sensor 28 is connected thereto.

The control section 22 includes a throttle sensor 24
A throttle signal from the engine, a rotational speed signal from the rotational speed sensor 26, a speed signal from the vehicle speed sensor, and a pressure sensor 28.
The injector 10 is basically controlled by the output signal outputted as an injector drive signal, and fuel is injected and supplied to the engine 2.

Furthermore, the output signal from the control section 22 is
output as a fuel pump drive signal to the fuel pump 16,
It is output as an ignition signal to the ignition coil 30 connected to the rotational speed sensor 26, and is also output as an ignition signal to the idling signal, which will be described later.
This signal is output to the speed control (ISC) control solenoid valve 32 as an ISC drive signal.

Furthermore, an idle speed control (ISC) control solenoid valve 32 is connected to the control section 22.

This solenoid valve 32 is provided in the middle of a bypass passage 34 that bypasses the throttle valve 8.

The control section 22 includes a throttle sensor 24
, rotation speed sensor 26, vehicle speed sensor, and pressure sensor 28
When the fuel cut control conditions are satisfied in the low vehicle speed range and low rotation range, the fuel cut control operation is delayed for a predetermined period of time, and the bypass air is turned off until the fuel cut control is started. Idle, which increases the amount of fuel and advances the ignition timing.
It has a control configuration to perform speed control control.

Specifically, the throttle switch (not shown) is in the ID OFF state, the vehicle speed is in a low speed range of 20〓/h or less and 1.1〓/h or more, and the engine speed Ne is In the case of a low rotation range of 2500 rpm or less, when the fuel cut control conditions based on other detection signals are satisfied, the fuel cut control operation, which is the fuel cut operation, is controlled to be delayed for 2 seconds.

[0024] During the 2 second delay time until the fuel cut control is started, the amount of bypass air is reduced to 50%.
%, and the ignition timing is controlled to be advanced to 30° CA.

[0025] Reference numeral 36 is an air cleaner.

Next, the operation of the fuel injection control device for the engine 2 will be explained with reference to a control flowchart.

When the program of the control flowchart is started (100) by the starting operation of the engine 2, it is determined (102) whether or not the throttle S/W is in the ID ON state. If YES, the determination (102) is repeated until the determination (102) becomes NO, and if the determination (102) is NO, a determination (104) is made as to whether the vehicle speed signal is within a predetermined range.

Then, in the judgment (104), if the vehicle speed signal is NO outside the range of 20〓/h≧vehicle speed≧1.1〓/h, the above-mentioned judgment of the ID ON state of the throttle S/W (102) is made. ) and the vehicle speed signal is 20〓/h≧vehicle speed≧
If YES within the range of 1.1/h, it is determined whether the rotation signal is Ne≦2500 rpm (106).

If this judgment (106) is NO, the above-mentioned judgment (10) of the ID ON state of the throttle S/W is made.
Returning to step 2), if the determination (106) is YES, it is determined (108) whether the throttle S/W is in the ID ON state.

If the ID ON state determination (108) of the throttle S/W is NO, the above-mentioned vehicle speed signal is 20.
〓/h≧Vehicle speed≧1.1〓 Return to the judgment (104) of whether or not it is within the range of /h, and if the judgment (108) is YES, check whether all other fuel cut conditions are satisfied. A determination (110) is made as to whether or not this is the case.

If this judgment (110) is NO, the above-mentioned judgment (10) of the ID ON state of the throttle S/W is made.
Returning to 2), if the determination (110) is YES, the fuel cut control operation is controlled to be delayed, and the delay time until the fuel cut control is started is set to KCFCDLY=KCFCDLY1 (2 seconds). During this 2 second delay time, set KDISC SB3 (50%) to increase the amount of bypass air, and set ABSE=KAIDL1 (30%) to advance the ignition timing.
°CA) (112).

Then, it is determined (114) whether or not KCFCDLY1 (2 seconds), which is the delay time until the fuel cut control is started, has elapsed.
) is NO, this judgment (114) is repeated until KCFCDLY1 (2 seconds) has elapsed, and judgment (1
If 14) is YES, a fuel cut control operation, which is a fuel cut operation, is performed.

[0033] As a result, during the two-second delay time until the fuel cut control is started, the amount of bypass air is increased and the idle/ignition timing is advanced to advance the ignition timing.
It performs speed control, prevents a drop in output, and reduces the difference in output between when the throttle valve is fully closed and when the throttle valve is fully open, suppressing vehicle vibration, and improving riding comfort. can.

Furthermore, by activating the fuel cut control after the delay time has elapsed, it is possible to prevent the temperature of the catalyst from rising and protect the catalyst, thereby extending the useful life of the catalyst, which is economically advantageous. It is.

Furthermore, by setting the delay time until the start of the fuel cut control to 2 seconds, there is no needless inconvenience of worsening fuel efficiency, and fuel efficiency can be maintained at a low price.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be modified in various ways.

For example, in the embodiment of the present invention, the delay time until the fuel cut control is started is set to KC.
Set FCDLY=KCFCDLY1 (2 seconds) and set KDISC S to increase the amount of bypass air.
B3 (50%) and ABSE=KAIDL1 (30°CA) to advance the ignition timing, but each value can be set as desired.

[0038]

As described in detail above, according to the present invention, a throttle sensor is provided for detecting the opening degree of a throttle valve provided in an engine, a vehicle speed sensor is provided for detecting the speed of a vehicle on which the engine is mounted, and the engine A rotation speed sensor is provided to detect the rotation speed of the engine, and when the output signals from each sensor are input and the fuel cut control conditions are satisfied in the low vehicle speed range and low rotation range, the fuel cut control operation is delayed for a predetermined period of time. Until this fuel cut control is started, a control section is provided that performs idle speed control control that increases the amount of bypass air and advances the ignition timing. By increasing the amount of bypass air and performing idle speed control that advances the ignition timing, it is possible to prevent a drop in output and reduce the difference in output between when the throttle valve is fully closed and when it is open. , the vibration of the vehicle can be suppressed and the riding feeling can be improved. In addition, by activating fuel cut control after a predetermined time has elapsed, it is possible to prevent the temperature of the catalyst from rising and protect the catalyst.
The service life of the catalyst can be extended, which is economically advantageous. Furthermore, by setting a short time until the fuel cut control is started, there is no needless inconvenience of worsening fuel efficiency, and fuel efficiency can be maintained at a low price.

[Brief explanation of drawings]

FIG. 1 is a control flowchart of an engine fuel injection control device showing an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of an engine fuel injection control device.

[Explanation of symbols]

2 Engine 4 Intake passage 6 Exhaust passage 8 Throttle valve 10 Injector 14 Fuel tank 18 Fuel regulator 22 Control unit 24 Throttle sensor 26 Rotational speed sensor 28 Pressure sensor 32 Idle speed control (ISC)
Control solenoid valve 34 Bypass passage

Claims (1)

[Claims] Claim 1: A fuel injection control device for an engine that controls the fuel injection amount according to the operating state of the engine, which includes a throttle sensor that detects the opening of a throttle valve provided in the engine, and which detects the speed of a vehicle in which the engine is installed. A vehicle speed sensor is provided to detect the rotation speed of the engine, and a rotation speed sensor is provided to detect the rotation speed of the engine.The output signals from each sensor are input, and when the fuel cut control conditions are satisfied in the low vehicle speed range and low rotation range, a predetermined A control unit is provided to perform idle speed control that delays the fuel cut control operation by a certain amount of time, increases the amount of bypass air, and advances the ignition timing until the fuel cut control is started. Features: Engine fuel injection control device.