JPS6338643A - Electronically controlled fuel injection device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent fuel from becoming excessively rich at the time of acceleration from a high load in which the rate of load change is small, by making the fuel increment at the time of acceleration nearly proportional to the rate of change in throttle valve opening and further making it nearly inversely proportional to the engine load. CONSTITUTION:A control unit 6 calculates a basic fuel injection quantity by means of the intake air quantity from an air flowmeter 8 and the number of revolutions from an engine speed sensor 5. And it calculates the rate of change in throttle valve opening on the basis of the detected value from a throttle valve opening sensor 4 and the engine load from the intake air quantity and number or revolutions. At the time of acceleration, the factor of acceleration increment is set so as to be nearly proportional to the rate of change in throttle valve opening, and further to be nearly inversely proportional to the engine load.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Field of Application> The present invention relates to an electronically controlled fuel injection device for an internal combustion engine, and more particularly to increasing control of the fuel injection amount during engine acceleration.

<Prior Art> Conventionally, electronically controlled fuel injection devices for internal combustion engines include the following.

That is, the intake air flow i detected by the air flow meter
Basic fuel injection ff1Tp (=KXQ/N;
After calculating various correction coefficients C0EF according to engine operating conditions such as engine temperature, air-fuel ratio feedback correction coefficient α, and correction numerator s depending on battery voltage, the basic fuel injection amount' is calculated. rp is corrected and the final fuel injection amount Tt (=TpxCOEFxα+Ts)
Set.

Then, by outputting an injection pulse signal with a pulse width corresponding to the set fuel injection lTi to the electromagnetic fuel injection valve, a predetermined amount of fuel was injected and supplied to the engine (JP-A-59-203 (See Publication No. 828, etc.).

By the way, when the engine is accelerating, there is a risk that the air-fuel ratio may become over-lean due to a delay in fuel supply, a delay in the detection of the intake air flow rate by the air flow meter, a delay in the calculation of the fuel injection amount, etc. By injecting and supplying the fuel in an amount larger than that of the fuel, the air-fuel ratio was avoided from becoming over lean.

Specifically, the acceleration increase coefficient K acc, which is set approximately in proportion to the rate of change in the opening degree Δθ of the throttle valve toward the open side, is included in the various correction coefficients C0FF, and when the rate of change in the throttle valve opening degree Δθ is large. In other words, during sudden acceleration, the fuel injection amount Ti
I was trying to increase it. In addition, by inserting an l'lt injection pulse signal with a pulse width corresponding to the increased fuel injection amount (also set based on the throttle valve opening change rate Δθ) between the normal injection pulse signals, the fuel injection amount can be increased. Some are designed to increase the amount of
1-081187 etc.).

<Problem to be solved by the invention> By the way, in this way, the throttle valve opening change rate Δ
When setting the increase correction amount of the fuel injection amount during acceleration based on θ, it is necessary to make sure that the throttle valve opening rate Δθ detected as in the case of acceleration from points A and B shown in Fig. 4 is the same. If there is, the acceleration increase will be made at the same level (same increase rate or same amount) regardless of the change in engine load at that time.

However, the amount of increase required by the engine originally increases in proportion to the rate of change in the engine load, and as shown in Figure 5, for example, when accelerating from point A and accelerating from point B, the throttle valve opening changes. Although the rate Δθ is the same, the engine load change rate at that time is greater for acceleration from point B (as is clear from the figure, if the throttle valve opening change rate Δθ is the same, acceleration from low load is higher). (increases the rate of change in engine load), so the amount should originally be increased more when accelerating from point B than when accelerating from point A.

For this reason, in the past, if the acceleration increase was set to match the acceleration from a low load, too much fuel would be increased when accelerating from a high load, resulting in an overlift of the air-fuel ratio, resulting in engine breathlessness and two ignitions. Smoking of the stopper, deterioration of exhaust properties,
There was a risk that problems such as deterioration of fuel efficiency would occur.

The present invention has been developed in view of the above-mentioned problems, and is intended to enable the setting of an increase in the amount of fuel injection during acceleration commensurate with the amount required by the engine.

Means for Solving the Problems> Therefore, in the present invention, as shown in FIG. a throttle valve opening change rate detecting means for detecting a rate of change in opening of a throttle valve to the open side, which is installed in an intake passage of the engine; an engine load detecting means for detecting a load on the engine; increased fuel injection amount setting means for setting the increased fuel injection amount substantially proportional to the throttle valve opening change rate detected by the rate detection means and substantially inversely proportional to the engine load detected by the engine load detection means; a fuel injection valve drive control means for driving and controlling the fuel injection valve according to the increased fuel injection amount set by the increased fuel injection amount setting means and the fuel injection amount set by the fuel injection amount setting means; The engine's electronically controlled fuel injection system was configured.

According to this electronically controlled fuel injection system for an internal combustion engine, the increased fuel injection amount is set according to the detected rate of change in the throttle valve opening toward the open side, that is, during sudden acceleration where the rate of change is large. Further, this increased fuel injection amount is corrected in inverse proportion to the engine load. That is, even if the rate of change in the throttle valve opening degree is the same, a larger amount of increased fuel injection is set in an acceleration state when the engine load is lower, and the amount of increased fuel injection can be set in accordance with the rate of change in the engine load.

<Example> An embodiment of the present invention will be described below based on the drawings.

FIG. 2 shows the hardware configuration of this embodiment.

A throttle valve opening sensor 4 that detects the opening θ of a throttle valve 3 installed in the intake passage 2 of the internal combustion engine 1, a rotation speed sensor 5 such as a crank angle sensor that detects the engine rotation speed N, and the engine 1. An air flow meter 8 for detecting the intake air flow IQ is provided, and each detection signal from these is input to a control unit 6 having a built-in microcomputer.

Based on these detection signals, the control unit 6 sets the fuel injection iTi by increasing the amount when the engine 1 accelerates, and outputs an injection pulse signal with a pulse width corresponding to this fuel injection 4]Ti to the fuel injection valve 7. do. That is, in this embodiment, the control unit 6 corresponds to a fuel injection amount setting means, an increased fuel injection amount setting means, and a fuel injection valve drive control means. The rotation speed sensor 5 and the air flow meter 8 constitute engine load detection means.

Here, the fuel injection amount Ti by the control unit 6
The settings will be explained based on the flowchart in FIG.

In step I (indicated as "S" in the figure, the same applies hereinafter), the detected intake air flow IQ.

Input the engine rotation speed N and throttle valve opening θ.

In step 2, the intake air flow IQ input in step 1 is
Basic fuel injection ff1Tp is determined by
(-KXQ/N; is a constant) is calculated.

In step 3, the rate of change Δθ of the throttle valve opening θ is calculated based on the throttle valve opening θ input last time and the throttle valve opening θ input this time (Δθ−(θ−θI
)/Δt; Δt is the execution timing of this flowchart).

In step 4, it is determined whether the engine 1 is in an accelerating state based on Δθ calculated in step 3.

That is, when the Δθ indicates that the throttle valve 3 is opened at a rate equal to or higher than a predetermined rate, the engine 1 is assumed to be in an accelerating state and the process proceeds to the next step 5, and when the engine 1 is not in an accelerating state, steps 5 to 5 are performed. 8 acceleration increase coefficient Kac
c Jump to settings and proceed to step 9.

In step 5, the acceleration increase coefficient K accl is searched from the map based on Δθ calculated in step 3. In this map of the acceleration increase coefficient Kaccl, the acceleration increase coefficient Kaccl is set approximately in proportion to Δθ, and the larger Δθ is, the larger the acceleration increase coefficient Kaccl is set, so that more acceleration is increased. It's Nishide. That is, when Δθ is large, the engine 1 is rapidly accelerating, so
The aim is to increase the quantity of fuel to avoid delays in fuel supply.

In step 6, the acceleration increase coefficient K acc2 is searched from the map based on the basic fuel injection amount 'rp calculated in step 2. The map of this acceleration increase coefficient K acc2 is approximately inversely proportional to the basic fuel injection ITp.
acc2 is set, and the smaller the basic fuel injection amount 'rp, that is, the engine load, the larger the acceleration increase coefficient Kacc2 is set, so that a larger amount of acceleration can be increased. In other words, as shown in Fig. 5, even if the rate of change in throttle valve opening is the same Δθ, the rate of change in load is greater when accelerating from a low load state, so the The increase rate of the fuel injection amount Ti is thereby changed, thereby making it possible to perform an increase correction corresponding to the rate of change in the engine load.

Further, the acceleration increase coefficient K acc2 may be set by calculation based on the formula shown below.

K acc2 = (4/4 T 1) - Tp before acceleration)
/(4/4Tp-R/LTp) However, 4/4Tp is the basic fuel injection IT p when the throttle valve is fully open. SR/LT p is the Road Lo
The basic fuel injection amount 'rp of ad is shown. Furthermore, Road L
Minimum basic fuel injection IT during deceleration instead of oadTp
p old N may be used.

In this case, when the acceleration increase coefficient K acc2 is set by a map, the computation time of the comparison control unit 6 can be shortened and the control accuracy can be improved.

In this example, the basic fuel injection ITp was used as a representative of the engine load, but this basic fuel injection amount 'rp
In addition, suction negative pressure, suction air flow ff1Q/engine rotation speed N
, throttle valve opening area/engine rotational speed N, etc. may be used, and furthermore, intake air flow i under a predetermined rotational speed condition may be used.
Q or throttle valve opening θ may be used.

In step 7, the acceleration increase coefficient K acc3 is searched from the map corresponding to the cooling water temperature Tw. Then, when the cooling water temperature is low, the acceleration increase coefficient K acc is increased.

In step 8, the acceleration increase coefficients Kaccl, Kacc2. By multiplying by Kacc3, an acceleration increase coefficient Kacc (this acceleration increase coefficient Kacc is included in various correction coefficients C0EF) is set, which is used as a correction coefficient when calculating the final fuel injection amount Ti.

In step 9, after calculating various correction coefficients C0EF, air-fuel ratio feedback correction coefficient α, and correction numerator s based on battery voltage, the basic fuel injection ff calculated in step 2 is
1Tp is corrected and the final fuel injection lTi (=
TpXCOEFXα+Ts). Here, the various correction coefficients C0EF are composed of a water temperature correction coefficient Ktw, a starting correction coefficient Kas+, an after-idle increase correction coefficient Kai, an air-fuel ratio correction coefficient Kmr, and an acceleration increase coefficient 'IJ Kacc set in step 8. (COE
F = Ktin+ Kas+ Kai+ Kmr+
Kacc).

The water temperature correction coefficient KL- is used to improve engine operability by increasing the fuel injection amount Ti when the engine is cold, and is set to be inversely proportional to the cooling water temperature Tw. The start correction coefficient Kas is also set to be inversely proportional to the cooling water temperature Tw in order to improve the startability of the engine 1, and is designed to increase the amount when the ignition switch is turned on. The post-idle increase correction coefficient Kai causes the amount to be increased in accordance with the coolant temperature Tw immediately after starting, in order to smooth the start. The air-fuel ratio correction coefficient Kmr is the basic fuel injection ff1T
p and the engine rotational speed N are stored in correspondence with each other, and the air-fuel ratio correction is made in accordance with the operating state of the engine 1 by increasing the value at high speeds and high loads.

Further, as described above, the acceleration increase coefficient K acc is set based on the throttle valve opening change rate Δθ and the basic fuel injection amount 'rp, which is the engine load, in response to changes in the acceleration state and the engine load. Therefore, it is possible to make an increase correction in accordance with the amount required by the engine during acceleration.

In this embodiment, the increase correction (setting of increased fuel injection amount) of the fuel injection amount Ti, which is inversely proportional to the engine load, is performed using various correction coefficients C0EF (specifically, acceleration increase coefficient Kac
c), but the acceleration increase coefficient K acc is set only by the throttle valve opening change rate Δθ as in the past, and the detected value used for calculating the basic fuel injection amount 'rp is set by changing the acceleration increase coefficient K acc. intake air flow fiQ
may be corrected by making it substantially inversely proportional to the engine load at that time. However, in this case, the acceleration increase coefficient K acc2
For the correction amount corresponding to , the acceleration increase coefficient K acc2 is determined in real time not at 'rp before acceleration but at Tp (indicating the direction of increase of 1) during acceleration.

Furthermore, in so-called asynchronous interrupt injection in which additional fuel injection is performed between normal fuel injections, the injection amount may be set based on the throttle valve opening change rate Δθ and the engine load as described above. good.

<Effects of the Invention> As explained above, according to the present invention, when the engine is accelerating, the amount of fuel injection can be increased in accordance with the amount required by the engine, avoiding overriching of the air-fuel ratio, etc.
Breathing during engine acceleration.

This has the effect of preventing deterioration of exhaust properties.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of the present invention, Fig. 2 is a system diagram showing an embodiment of the present invention, Fig. 3 is a flowchart showing fuel injection amount setting in the same embodiment, and Fig. 4 shows problems of the conventional method. A time chart for explanation, FIG. 5, is a graph showing the relationship between the throttle valve opening and the engine load. 1... Internal combustion engine 2... Intake passage 3... Throttle valve 4... Throttle valve opening sensor 5...
・Rotation speed sensor 6...Control unit
7...Fuel injection valve 8...Air flow meter Patent applicant Japan Electronics Co., Ltd. Agent Patent attorney Fujio Sasashima Figure 2 Figure 4 (Japanese 1 Seki 1 cargo conversion rate) Figure 5 Ku engine Rotating upper hand 3 da ε Juho Seisho (self-proposal) May 29, 1988 Commissioner of the Patent Office Black 1) Akio Yu Tono 1, Indication of the incident 1986 Patent Application No. 182011 2, Name of the invention Internal combustion engine Electronically controlled fuel injection device 3, relationship with the case of the person making the amendment Patent applicant: Address: 1, 1671 Kasuyo-cho, Isesaki City, Gunma Prefecture Name: Hiki Electronics Co., Ltd. Representative: Shigemi Sugino 4, Agent address: Daisan Mori Building 6, 4-10 Nishi-Shinbashi-chome, Minato-ku, Tokyo Contents of the amendment (1) In the second line of page 3 of the specification, the phrase ``delay in fuel supply'' has been replaced with ``delay in the supply of fuel to the cylinder.'' ``Delay in supply.'' (2) On page 4, line 18 of the specification, the phrase "the amount should be increased" should be amended to "the amount should be corrected to increase." (3) On page 4, line 19 of the specification, the phrase "low load" is corrected to "for example, low load (point B)." (4) On page 4, line 20 of the specification, the phrase "high load" is corrected to "high load (point A)."that's all

Claims (1)

[Claims] A fuel injection amount setting means that sets the fuel injection amount based on the intake air flow rate and rotational speed of the internal combustion engine, and a throttle that detects the rate of change in the opening degree of a throttle valve installed in the intake passage of the engine toward the open side. a valve opening change rate detection means; an engine load detection means for detecting engine load; and an increased fuel injection amount approximately proportional to the detected throttle valve opening change rate and approximately inversely proportional to the detected engine load. an increased fuel injection amount setting means for setting the increased fuel injection amount, and a fuel injection valve is driven and controlled according to the increased fuel injection amount set by the increased fuel injection amount setting means and the fuel injection amount set by the fuel injection amount setting means. An electronically controlled fuel injection device for an internal combustion engine, comprising: fuel injection valve drive control means.