JPH02201046A - Electronic fuel injection control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent ill influence on exhaust gas by stopping fuel supply in the post-start increased amount when either of the three conditions is met; i.e., an idle switch is turned off, the car speed has exceeded the set value, and the degree of throttle opening has exceeded the set value. CONSTITUTION:In case an internal combustion engine 2 is in cranking, a control means 38 judges that the engine 2 is fully started when the engine revolving speed sensed by a revolving speed sensor 40 has attained a specified value (for ex., 500rpm). This judgement about starting shall immediately lead to fuel supply in the post-start increased amount. With progress of warming-up this post-start fuel amount shall be decreased gradually to be stopped momentarily when either of the three conditions is met; i.e., an idle switch 42 is turned off, the car speed given by a car speed sensor 44 has exceeded the set value (for ex., 2km/h), and the degree of throttle 28 opening given by a throttle opening sensor 36 has exceeded the set value.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an electronic fuel injection control device for an internal combustion engine, and in particular, if a predetermined condition is satisfied after starting the supply of increased fuel after starting, The present invention relates to an electronic fuel injection control device for an internal combustion engine that can maintain a proper air-fuel ratio without affecting exhaust gas by quickly stopping the supply of increased fuel.

[Conventional technology]

Some internal combustion engines of vehicles are equipped with an electronic fuel injection control device as a countermeasure to problems such as harmful components of exhaust gas and fuel consumption rate. This electronic fuel injection control device
Changes in engine operating conditions such as engine speed, cooling water temperature, intake air amount, etc. are input as electrical signals to control the operation of the fuel injection valves.

As such a fuel injection device, for example, JP-A-62-
It is disclosed in Japanese Patent Application Laid-open No. 157246 and Japanese Patent Application Laid-open No. 62-63151. The system disclosed in Japanese Patent Application Laid-Open No. 61157246 controls the increase in the amount of fuel supplied after starting the internal combustion engine to a value that corresponds to the rotational speed and load condition of the internal combustion engine. Furthermore, the method described in Japanese Patent Application Laid-open No. 62-63151 performs fuel increase correction when cold or under high load, and also performs fuel reduction correction during high load operation exceeding a predetermined load during cold conditions. This is what we do.

Further, in the fuel injection control method, Section 4 (a), (
b) As shown in the figure, when cranking is started (indicated by X position) and the engine speed reaches 500 rpm (indicated by In this case, due to reasons such as unstable valve clearance or poor fuel atomization, the air-fuel ratio shifts to the lean side after a certain amount of time has passed after the engine is fully warmed up and started. In order to eliminate this inconvenience, post-start booster fuel is supplied for a predetermined time t from the time when a complete start is determined (indicated by the X position). In this case, regardless of the engine speed, the amount of additional fuel after starting is proportionally reduced from the time of full start (indicated by position There is.

Furthermore, in the fuel injection control method, FIGS.
As shown in b), the ignition pulses are counted when the amount of extra fuel after starting is gradually reduced from the complete start (indicated by X position) to the end after a predetermined time t has elapsed (indicated by X position). The amount of extra fuel after starting is decreased for each pulse, and as a result, the engine speed increases at the time of starting, increasing the rate of decrease in the amount of extra fuel after starting.

[Problem that the invention seeks to solve]

Incidentally, in a conventional fuel injection control device, control is performed so that the increased amount of fuel after starting becomes zero after a predetermined period of time has elapsed from the time of complete starting, or after the number of injections (ignitions), regardless of the running state of the vehicle.

For this reason, when driving with increased fuel supplied after startup, the air-fuel ratio has shifted to the Lynch side, so Go and H
The amount of C emissions increases after the vehicle starts. Therefore, the supply of additional fuel after normal startup is set to end at straight 11j when the vehicle starts in exhaust gas mode.

However, when controlling the supply of extra fuel after starting in this way, the supply of extra fuel after starting is stopped earlier than the requested time, and after that, because the 02 sensor is inactive, before feedback control is performed. This resulted in the inconvenience that the air-fuel ratio became lean. For this reason, it is desired to prevent the air-fuel ratio from becoming lean by extending the fuel supply after the start, but due to exhaust gas regulations, it is not possible to supply increased amount of fuel after the start after the vehicle has started, and an improvement is desired. Ta.

[Purpose of the invention]

Therefore, the purpose of this invention is to eliminate the above-mentioned disadvantages.
If a predetermined condition is satisfied after the internal combustion engine is completely started, the supply of additional fuel after starting is quickly stopped.
An object of the present invention is to realize an electronic fuel injection control device for an internal combustion engine that can maintain an appropriate air-fuel ratio without affecting exhaust gas.

Means for Solving Problem C) In order to achieve this object, the present invention provides an electronic system for an internal combustion engine that controls fuel injection to control the air-fuel ratio by supplying increased amount of fuel after the internal combustion engine is completely started. In the fuel injection control device, when at least one of the following conditions is satisfied: the idle switch is turned off, the vehicle speed has become north of the set vehicle speed, and the throttle valve opening has exceeded the set opening. The present invention is characterized in that a control means is provided for quickly stopping the supply of increased fuel after the start.

[Effect]

According to the configuration of the present invention, the control means selects at least one of the following conditions: the idle switch is turned off, the vehicle speed is equal to or higher than the set vehicle speed, and the throttle valve opening is equal to or higher than the set opening. If the above is satisfied, control is performed to quickly stop the supply of increased fuel after startup. Thereby, the air-fuel ratio can be made appropriate without affecting exhaust gas.

〔Example〕

Embodiments of the present invention will be described in detail below based on the drawings.

Let me explain in detail.

FIG. 1.2 shows a first embodiment of the invention. In the figure, 2 is an internal combustion engine, 4 is an air cleaner, 6 is an air flow meter, 8 is a throttle body, 10 is a body intake passage, I2 is an intake manifold, 14 is a manifold intake passage, 16 is an intake valve, 18 is a combustion chamber, 20 2 is an exhaust valve, 22 is an exhaust manifold, 24 is an exhaust passage, and 26 is a three-way catalyst device. An intake throttle valve 28 is disposed within the body intake passage 10. Further, a cold start fuel injection valve 30 is attached to the intake manifold 12 on the throttle body 8 side, and a fuel injection valve 32 for injecting fuel into the combustion chamber 18 side on the internal combustion engine 2 side is attached. has been done.

An 02 sensor 34, which is an air sensor that detects the oxygen concentration in exhaust gas, is attached to the exhaust manifold 22.

The air flow meter 6 that detects the amount of intake air, the throttle opening sensor 36 that detects the opening state of the intake throttle valve 28, the fuel injection valve 32, and the 02 sensor 34 are in communication with a control means 38. The control means 38 also includes an engine speed sensor 40, an idle switch 42, and a vehicle speed sensor 44.
Detection means such as

When the internal combustion engine 2 is fully started, that is, when the engine speed Ne reaches 500 rpm, the control means 38 is configured to perform a complete start in order to stabilize the valve clearance, promote atomization of the fuel r1, etc. The condition under which the idle switch 42 is turned off and the set vehicle speed (e.g. 2km/h) is determined when the supply of increased fuel is started after the start.
If at least one of the above conditions and the condition that the opening degree of the intake throttle valve 28 becomes equal to or higher than the set opening degree θ are satisfied, the control is performed so as to quickly stop the supply of increased fuel after starting. be.

Next, the operation of this first embodiment will be explained based on the timing chart of FIG. 2.

(indicated by the X position to start cranking the internal combustion engine 2),
When the engine speed Ne reaches 50 rpm (indicated by the X position), it is determined that the internal combustion engine 2 has been completely started, and the supply of increased fuel is started after the start.

As the internal combustion engine 2 warms up, the amount of additional fuel after starting decreases, but under the conditions that the idle switch 42 is turned off and the vehicle speed exceeds the set vehicle speed (for example, 2 km/h), the intake air When at least one of the conditions in which the opening degree of the throttle valve 28 becomes the set opening degree 0 or more is satisfied (indicated by the X position), in this first embodiment, the increased amount of fuel after starting is instantaneously reduced to zero. do.

As a result, when the vehicle starts, the amount of additional fuel after starting becomes zero in a short time, so even if the 02 sensor 34 remains inactive, the amount of fuel increases without affecting the exhaust gas. The fuel ratio can be maintained appropriately.

In this first embodiment, when one of the three conditions mentioned above is satisfied, the additional fuel after starting is instantly brought to zero, but the increase in fuel is made to zero after starting, but it is delayed for a predetermined period from position X in FIG. It is also possible to instantly reduce the fuel consumption to zero after starting the engine.

FIG. 3 shows a second embodiment of the invention. In this embodiment, parts that perform the same functions as those in the first embodiment described above will be described with the same reference numerals.

This second embodiment is characterized by the following points. That is, when one of the three conditions mentioned above is satisfied (
(indicated by X position), a control means 38 is provided for reducing the amount of increased fuel after startup to zero with a large slope from this X position.

According to the configuration of this second embodiment, when the above-mentioned first condition is satisfied, the increased fuel amount after startup is not instantaneously reduced to zero;
Moreover, since the reduction time of increased fuel after startup is not unnecessarily prolonged, drastic fluctuations in the air-fuel ratio can be avoided, and the internal combustion engine
The operating condition of the vehicle can be improved.

Further, in this second embodiment as well, it is possible to delay the increased amount of fuel after starting for a predetermined time from the X position and then reduce the increased amount of fuel to zero with a large slope.

〔Effect of the invention〕

As is clear from the above detailed description, according to the present invention,
If at least one of the following conditions is satisfied: the idle switch is turned off, the vehicle speed or opening is greater than the set opening, and the throttle valve opening is greater than the set vehicle speed, an increased amount of fuel is supplied after startup. By providing a control means for controlling the engine to stop quickly, the air-fuel ratio can be maintained constant without affecting exhaust gas.

[Brief explanation of the drawing]

Figure 1.2 shows a first embodiment of the present invention, Figure 1 is a schematic diagram of an electronic fuel injection control device, and Figures 2 (a) and (b) explain the operation of this first embodiment. This is a timing chart. FIGS. 3(a) and 3(b) are timing charts illustrating the operation of the second embodiment of the present invention. FIGS. 4(a) and 4(b) and FIGS. 5(a) and 5(b) are timing charts of conventional fuel injection control, respectively. In the figure, 2 is an internal combustion engine, 8 is an intake manifold, and 28 is an internal combustion engine.
is the intake throttle valve, 32 is the fuel injection valve, 34 is the 02 sensor,
36 is a throttle opening sensor, 38 is a control means, 40 is an engine speed sensor, 42 is an idle switch, and 4
4 is a vehicle speed sensor.

Claims (1)

[Claims] 1. In an electronic fuel injection control device for an internal combustion engine that controls fuel injection to control the air-fuel ratio by supplying increased amount of fuel after the engine has started completely, the conditions under which the idle switch is turned off and the vehicle speed are the set vehicle speed. If at least one of the above conditions and the condition that the throttle valve opening is equal to or higher than the set opening is satisfied, a control means is provided for controlling the supply of the increased amount of fuel after the startup to be quickly stopped. An electronic fuel injection control device for an internal combustion engine, characterized in that: