JPS60261947A - Accelerative correction of fuel injector - Google Patents

Abstract

PURPOSE:To improve the accelerative performance by correcting the synchronous fuel injection under acceleration with correspondence to the operating conditions. CONSTITUTION:Under steady acceleration, it will pass through the right loop to produce no interruption pulse if DELTAQa (variation of intake air) is lower than predetermined level while to produce TA1 pulse upon exceeding over predetermined level. Under acceleration from idling, pulse TA2 due to after idling is produced from the central loop. When accelerating from deceleration, it will pass through the right loop resulting in improvement of acceleration performance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a fuel injection device for an internal combustion engine for an automobile, and more particularly to a method for correcting the fuel injection amount during acceleration to obtain good acceleration performance.

[Background of the invention]

As described in Japanese Unexamined Patent Application Publication No. 59-5841, the correction method during acceleration in a conventional fuel injection device does not include detailed correction of the increase pulse depending on the operating conditions of the engine. However, in the air flow meter used in the present invention, there is no obstruction to the intake air unlike the conventional vane type, and air flows into the engine instantly, so detailed corrections are required during acceleration. It has become.

[Purpose of the invention]

An object of the present invention is to provide good acceleration performance of an internal combustion engine by optimizing the correction method during acceleration when using a hot wire air flow meter.

[Summary of the invention]

Conventionally, the electronic fuel injection device (MPI system) on the market uses a Vi vane type air flow meter, so there is no sudden increase in the intake air amount of the engine during acceleration. A relatively rich mixture was being supplied to the However, due to the inherent delay in air intake to the engine, spectacular acceleration could not be achieved. on the other hand,
Since the air amount sensor used in the present invention does not have a throttle configuration, it has the advantage that air can reach the engine quickly during acceleration, but a delay in fuel follow-up has been a problem.

It has been found that this fuel delay amount Vi cannot be kept at a constant value as in the conventional method because air intake is delayed, and that it is necessary to precisely correct it based on acceleration and other factors.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 illustrates an engine and an embodiment for carrying out the present invention. The engine l has an intake pipe 2 having injectors 3 corresponding to the number of cylinders, and this intake pipe is connected to an upstream collector. 4, and has a throttle valve further upstream that determines the intake end of the engine. Further, the intake air t of the engine is measured by an air flow sensor 6 provided further upstream. On the other hand, the rotational speed of the engine is detected by a rotation sensor 3. In addition, the engine temperature 11° and the exhaust gas signal lO are input to the control unit 12. Fuel is supplied to the engine by opening the valve of the injector 3, and the amount of fuel is measured once every valve opening time.

Further, the pressure of the fuel is regulated by means of a fuel pump 8 and a regulator 9.

FIG. 2 shows the input/output relationship shown in FIG. 1 using a block diagram. + indicates sensors, and the right side indicates actuators. In addition, inside the ECU, there is a waveform shaping circuit shown in the pressure section, an AD converter, input/output exchange, and l10 that performs arithmetic processing.
An LSI section, a CPU that issues commands to the LSI section, and a circuit for driving output actuators are arranged on the right side.

Next, we will explain the injection timing using Fig. 3.Injection in a normal 4-cylinder 4-cycle engine (injects fuel into all 4 cylinders once per rotation, that is, at the AXC timing). The additional pulse explained in the present invention is the pulse shown in part B, and the pulse is generated immediately when acceleration is detected, and fuel is injected at that timing.Also, as a method for detecting acceleration, In the present invention, the 0N-OFF signal of the idle SW means that the throttle is opened from the idle state,
There is a rate of change in the intake air amount Qa, etc., and the magnitude of acceleration can be detected by the magnitude of ΔQa/Qa between Δt.

FIG. 5 shows an example of how the interrupt additional pulse is set in an actual vehicle depending on the magnitude of acceleration. For example, the processing after acceleration is divided depending on the state before acceleration.

That is, after fuel cut during deceleration, it is necessary to supply a large amount of fuel in order to dry up the intake string during fuel cut. Even in a steady state, it is necessary to change the amount of acceleration compensation depending on whether the throttle is fully closed or not. Furthermore, acceleration is detected using both changes in the amount of intake air and the idle switch, and what is referred to as "after idle" is an acceleration interrupt pulse generated by acceleration detection by the idle switch.

To explain each typical example using lateral pressure, first, after deceleration and fuel cut, it is divided into slow acceleration and sudden acceleration, and during slow acceleration, the pressure is 3 m3. During sudden acceleration, 9m8 is injected multiple times (each time acceleration is detected). In addition, acceleration detection is performed using the idle SW and ΔQ.
The reason for this is due to experimental data showing that detection at the idle switch is always faster than detection by ΔQa (the reason is that although the delay in the intake system is less in the case of ΔQa, the throttle opening (Depends on how big it is).

The interrupt pulse due to this idle 8WK is set to a relatively large value of 9m8 as an example.

Furthermore, during steady state, there is less dry-up of the intake pipe, so the interrupt pulse due to idle 8WK may be smaller, such as 3 m8, than during deceleration.

Furthermore, when the idle switch is OFF, that is, when accelerating from an open state, conditions are better such as the air-fuel mixture in the intake pipe being more uniform than when the throttle is closed. No acceleration correction is required.

Experimental results obtained by applying these corrections are shown in FIG. The example in Figure 6 is an example of no-load full-throttle sudden acceleration from idle, but the rise time of rotation is 200m compared to the conventional TI due to the application of interrupt additional pulse correction during acceleration.
It has been found that it is possible to improve l 20'm from 8 degrees to 8 degrees as T2.

Fig. 7 shows a flowchart for realizing the correction method explained in Fig. 5. First, acceleration in steady state passes through the right loop, and when ΔQa is smaller than AI, there is no interrupt pulse, and when ΔQa is smaller than AI, there is no interrupt pulse. outputs a TAN pulse. Note that originally, the additional pulse should be distinguished from TAX' (6m5 in FIG. 5) and T A l '' (3m8) by determining 71j>ΔQa>Ai, but
In the flowchart, this is omitted in all the flows below.

Next, in the center loop, pulse TA2 (, 3m5) due to after-idle is set during acceleration from idle, and then ΔQa is determined and additional pulse TA3 (also here, TA3' (3m8) TA3' (6m8)) is set. 2 types).

The loop on the left is the case of acceleration from deceleration. In this case, TA4 (9m8) is output at after idle, and the acceleration is further determined by ΔQa, and when A5>ΔQa>A6, a TA6 (3mS) pulse is output. This completes the correction. In all of these corrections, the correction pulse based on ΔQa is performed only once per acceleration, but in actual engine tests, the problem of insufficient acceleration remains during sudden acceleration after deceleration cut. Another feature of the present invention is that this part has been improved. That is, ΔQa
>A5, the correction pulse TA5 is set, and this TAS is outputted. Only under this condition, the TAS correction based on the determination of ΔQa>A5 can be repeated.

[Effects of the Invention] 1. As described above in the embodiment, by changing the correction amount by determining the conditions for interrupt correction during acceleration, it is possible to obtain good acceleration performance as shown in the experimental example. Furthermore, by applying the condition determination for correction after deceleration fuel cut, which is a feature of the present invention, it has been possible to break the conventional concept that it is difficult to achieve both acceleration matching during deceleration and steady state.

[Brief explanation of the drawing]

1st. 2- is a system diagram implementing the present invention, Section 3.4
Figure 5 is an explanatory diagram of injection timing, Figure 5 is a detailed diagram of the present invention, Figure 6 (9) is a BA diagram of the experimental results according to the present invention, and Figure 7 is an explanatory diagram of a flowchart for realizing the present invention. It is. 1...Engine, 3...Injector, 6...Intake air No. 3

Claims (1)

[Claims] 1. Controls the opening of the fuel injector according to pre-programmed control contents based on various operating parameters including the intake air amount, rotation speed, and temperature of the engine. In a fuel injection system for an internal combustion engine that has a function of inputting a signal to detect the closed state of a throttle valve that controls the amount of fuel, it is possible to increase or export fuel independently of the opening pulse of the injection valve that injects the basic amount of fuel during steady state. A valve opening pulse generating means is provided, and the width of this increasing pulse is made to depend on the amount of change in intake air amount per unit time, the closing signal of the throttle valve, the rotation speed signal of the internal combustion engine, etc., independently of the basic pulse width. An acceleration correction method for a fuel injection device, characterized in that: