JPH0454239A - Electronic controller for internal combustion engine - Google Patents

Abstract

PURPOSE:To most suitably control fuel injection irrespective of a negative pressure ambient characteristic of an injector by providing a correcting means for correcting a fuel injection time according to an ambient pressure of the injector. CONSTITUTION:During the operation of an engine, an ECU 15 determines a fuel injection quantity mainly on the basis of signals output from an air flow sensor 2, a crank angle sensor 13 and a water temperature sensor 9, to thus perform fuel injection in synchronism with the signals of the crank angle sensor 13. In calculating the fuel injection quantity by means of the ECU 15, parameters such as an ambient pressure, throttle opening degree and A/N of an injector are read out, and a correction factor is determined. The correction factor is added to the sum of initial correction, which is generally performed, obtaining the sum of new initial correction. The sum of the initial correction is multiplied by a basic fuel injection time, followed by addition of an ineffective fuel injection time, thus obtaining a fuel injection time.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention provides f/iI adjustment to prevent an excessive amount of fuel injection.
This relates to an electronic control device between internal combustion engines.

[Prior Art] Conventionally, for example, an electronic control device as shown in FIG. 3 has been disclosed in Japanese Patent Laid-Open No. 162341/1983. This is a hot wire fuel injection device, 1 is an air cleaner,
2 is a hot wire type air flow sensor, and 3 is an air temperature sensor that detects the atmospheric temperature. 4 is a throttle valve that controls the intake air amount of the engine 16; 5 is a throttle valve opening sensor that is connected to the throttle valve and detects the throttle valve opening; 6 is a surge tank; 7 is an upstream and a downstream of the throttle valve 4. A bypass air amount regulator 8 is provided in a passage bypassing between the intake manifold and the intake manifold.

9 is a water temperature sensor provided in a cooling water passage for cooling the engine, and 10 is an injector attached to each cylinder, which injects fuel determined by the ECU 15.

11 is an intake valve driven by a cam (not shown); 12
indicates a cylinder 0 Figure shows one cylinder of an engine, but it actually consists of multiple cylinders. 13 is a crank angle sensor, and 14 is a neutral detection switch for notifying that the engine is under no load.

The ECU 15 mainly determines the fuel injection amount based on the signals of the air flow sensor 2, crank angle sensor 13, and water temperature sensor 9, and performs fuel injection in synchronization with the signal of the crank angle sensor 13. The signals from the sensor 5 and the neutral detection switch 14 act as auxiliary parameters. The ECU 15 also controls the bypass air amount regulator 7.

FIG. 2 is a diagram explaining the configuration of the ECU 15 in FIG. 1. In FIG.
It is input to 52 ports or 6 interrupt terminals. The analog interface 153 is an interface circuit for analog inputs such as the air flow sensor 2, throttle opening sensor 5, water temperature sensor 9, and air temperature sensor 3, which are sequentially selected by the multiplexer 154 and analog-to-digital converted by the A/D converter 155. conduct, CPU
152 as a digital value. CPU152
is the ROM1521 in which the control program and data are written.
, a RAM 1522, and a timer 1523. The timer generates a pulse having a fuel injection pulse width calculated by a predetermined control program.

The drive circuit 156 is a drive circuit for driving the injector 10 with the pulse width. Further, the CPU 152 uses a timer to generate an ISC drive pulse width calculated according to a predetermined control program, and the drive circuit 157 is a drive circuit that drives the bypass air regulator 7 with the pulse width.

[Problem to be Solved by the Invention 1] However, when there is an injector negative pressure atmosphere as shown in FIG.
The air-fuel ratio A/F becomes about 4% richer from 50 mHg to 1550 mHg. This is because after fuel is injected into the gap at the tip of the needle valve 20 of the injector shown in FIG. There was a problem that the air-fuel ratio A/F was about 4% richer.

[Means for Solving the Problems] In order to solve such problems, the present invention corrects the fuel injection time (fuel injection pulse width) according to the negative pressure atmosphere of the injector, the throttle opening, and the A/N. This is how it was done.

[Fuel injection time (fuel injection pulse width) is corrected according to the negative pressure atmosphere of the coin injector, throttle opening, and A/N,
Since the corrected fuel is injected, even if fuel remains in the needle valve, it does not affect the fuel injection amount.

[Example] FIG. 1 is a flowchart for explaining the present invention in detail. In step 101, parameters (P) such as the atmospheric pressure or throttle opening of the injector, A/N, etc. are read out, and in step 102, Find the corrected count. In step 103, the correction coefficient obtained in step 102 is added to the sum of the corrections conventionally performed in the fuel injection control routine (not shown) (obtained by calculation) to obtain a new sum of corrections.

In step 104, basic fuel injection time 1. which is performed in a fuel injection control routine (not shown) is executed. (Basic fuel injection pulse width) is multiplied by the sum of the initial corrections obtained in step 103, and the invalid fuel injection time Tv carried out in the fuel injection control routine (not shown) is added to obtain the fuel injection time (fuel injection pulse width). Perform correction calculations. Note that C1 in step 103 is the sum of conventional initial corrections.

A case will be explained in which the parameter (P) in step 101 is the atmospheric pressure of the injector.

In step 102, correction coefficients as shown in FIG. 2, for example, are determined. The correction coefficients shown in FIG. 2 are obtained from the relationship between the atmospheric pressure of the injector and the fuel flow rate change rate shown in FIG. 5. Steps 103 and 104 are the same as those described above.

[Effects of the Invention] As explained above, the present invention corrects the fuel injection time (combustion injection pulse width) according to the atmospheric pressure of the injector, so it is optimal regardless of the negative pressure atmosphere of the injector, etc. This has the effect of allowing efficient fuel injection control.

[Brief explanation of the drawing]

Fig. 1 is a flowchart showing an example of the operation of the present invention, Fig. 2 is a graph showing correction characteristics, Fig. 3 is a block diagram showing the overall system of the engine, and Fig. 4 is a block diagram showing the structure of the ECU. , FIG. 5 is a sectional view showing details of the vicinity of the twenty-one dollar valve, and FIG. 6 is a graph showing the conventional characteristics. 1...Air cleaner, 2...Hot wire type air flow sensor, 3...Air temperature sensor, 4...
・Throttle valve, 5... Throttle opening sensor, 6
... Surge tank, 7 ... Bypass air volume regulator, 8 ... Intake manifold, 9 ... Water temperature sensor, 10 ... Injector, 11 ... Intake valve , 12...Cylinder.

Claims (1)

[Scope of Claims] An internal combustion engine comprising an air amount detection means for detecting the intake air amount of the engine, a rotation speed detection means for detecting the rotation speed of the engine, and a throttle opening degree detection means for detecting the opening degree of a throttle valve of the engine. An electronic control device for an internal combustion engine, which includes a correction means for correcting fuel injection time according to the atmospheric pressure of the injector, and performs optimal fuel injection control regardless of the negative pressure atmosphere characteristics of the injector.