JPH01134045A - Fuel injection controller for internal combustion engine - Google Patents

Abstract

PURPOSE:To perform accurate fuel injection control by compensating a fundamental fuel injection quantity set on the basis of engine speed and throttle opening on the basis of a controlled variable of an idling speed control valve in the case where air flow rate control is carried out by this idling speed control valve. CONSTITUTION:A control unit 15 calculates a controlled variable of an idling speed control valve 5 with a means 19 on the basis of each signal of a water temperature sensor 10 and a crank angle sensor 11 or the like. Likewise, it sets a fundamental fuel injection quantity with a means 16 on the basis of each signal of the crank angle sensor 11 and a throttle opening sensor 9. In this case, on the basis of a signal of the throttle opening sensor 9, an idling state is judged by a means 23. In addition on the basis of a signal out of a means 19, a correction value of the fundamental fuel injection quantity is calculated by a means 17. Then, on the basis of each signal of these means 16, 17 and 23, the fundamental fuel injection quantity is compensated by a means 18. Afterward, a fuel injection quantity in an injector is set by a means 20 on the basis of a signal or the like of this means 18.

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a fuel injection control device for an internal combustion engine that controls the operating state of an engine mainly based on throttle opening and engine speed. (Prior Art) Conventionally, this type of fuel injection control device for an internal combustion engine calculates the basic fuel injection ff1Tp from the throttle opening θ and the engine rotational speed N, and calculates the basic fuel injection ff1Tp from the above Tp with 0 and N as a grid. This is stored in the engine, and is taken out during engine operation and used for fuel injection control (see Figure 5).Then, for the above basic fuel injection stage, the engine speed, suction pipe negative pressure, water temperature, The fuel injection rA1 of the injector is controlled to the optimum air-fuel ratio by making corrections based on specifications such as vehicle speed (for example, Japanese Patent Laid-Open No. 55-32
(See Publication No. 913). (Problem to be Solved by the Invention 1) The problem here is that the idle speed control valve in the bypass passage, which is arranged parallel to the throttle valve, is used to control the air flow during low load, low rotation, or idling. If the method of adjusting the idle speed control valve If the area of the bypass passage is changed and the intake air m is changed, the air-fuel ratio will deviate from the set value.Also, this tendency becomes more pronounced at low rotation speeds and low throttle distances. The present invention has been made based on the above-mentioned circumstances, and it is an object of the present invention to perform a fuel injection error correction that takes into account the air flow rate passing through the idle speed control valve even when controlling the air flow rate using the idle speed control valve. Therefore, it is an object of the present invention to provide a fuel injection control device for an internal combustion engine that can realize fuel injection control with high precision even at low rotation speeds, low loads, or when idling.

[Means to solve the problem]

Therefore, in the present invention, an idle control valve that controls the idle engine speed of the engine is provided in a bypass passage that bypasses the throttle valve so that the engine speed converges to the target idle engine speed set by the water temperature. In a fuel injection control device comprising an idle control means for calculating a control m of the engine speed, and a basic fuel injection amount setting means for setting a basic fuel injection amount from a throttle opening degree and an engine speed, an idle state is determined from a throttle opening degree. an idle determination means for calculating a basic fuel injection amount correction value according to a control amount output from the idle control means; a basic fuel injection amount correction value calculation means for calculating a basic fuel injection amount correction value in accordance with a control amount output from the idle control means; and a basic fuel injection r14m correction value calculation means for idling. Basic fuel injection r that gives the basic fuel injection amount the correction value output from
JJ correction means.

[For production]

Therefore, even when air flow control is performed by opening and closing the idle speed control valve in the bypass passage that bypasses the throttle valve, fuel injection rA excitation correction is made commensurate with this, so in all operating ranges. Fuel injection control can be achieved with high precision.

【Example】

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings. In FIG. 1, reference numeral 1 is an engine, and its intake system 2 is provided with a throttle valve 3, and a bypass passage 4 arranged in parallel with this is provided with an idle speed control valve (hereinafter referred to as ISC valve) 5. It is being Further, a collector chamber 7 is provided downstream of the throttle valve 3. And the collector chamber 7
An injector 8 is installed near each intake boat of the engine 1 in the intake manifold downstream of the engine. Further, the throttle valve 3 includes a throttle opening sensor 9.
However, the engine 1 has a water temperature sensor 10. A crank angle sensor 11 is provided in the collector chamber 7, an intake temperature sensor 12 is provided in the collector chamber 7,
An air-fuel ratio sensor 14 having characteristics as shown in FIG. 4 is provided in the exhaust system 13 of the engine 1, and an atmospheric pressure sensor 6 is provided outside the engine 1. and,
Each of the above sensors 9°10, 11.14. The detection signal from the atmospheric pressure sensor 6 is also supplied to the control unit 15. Then, the control unit 15
As a result of calculations based on the detection signals from the sensors, appropriate control signals are sent to the injector 8 and the ignition coil 2.
2, etc. The control unit 15 has a configuration as shown in FIG. 2 regarding fuel injection control. That is, the control unit 15 includes a Shimamoto fuel injection m setting means 16 and a basic fuel injection amount correction value calculation means 1.
7. Basic fuel injection amount correction means 18, idle control means 1
9, fuel injection tJ4m setting means 20, air-fuel ratio correction value calculation means 21, feedback correction hanging sieving means 22, idle determination means 23, etc. are provided. Therefore, in the basic fuel injection amount setting means 1G, the detection signal θ of the throttle opening sensor 9 and the crank angle sensor 1
From the detection signal (engine speed) N from 1 to 1, the actual fuel injection ratio Tp is calculated from a map (Fig. 5) or the like. In addition, the basic fuel injection j correction value deriving means 17 calculates the control value tl of the ISO valve 5 calculated by the idle control means 19.
The control all signal corresponding to llffiDout is taken in, and from this the correction 1tTpbac-g(Dout) to the basic fuel injection 1)1 fit T p$ is calculated. Here, the above-mentioned control filter D out is given by, for example, a duty ratio. This correction value l”pbac is
C valve 5 control ll fl [) 0 tlt change,
In other words, it corrects fluctuations in the air-fuel ratio due to changes in the air flow rate flowing down the bypass passage 4. For example, the control fi
[) If the ISC valve 5 is installed so that the air flow rate increases as out increases, the correction value T
pbac is given by an increasing function for control ff1Doui. The above-mentioned idle control means 1 uses the basic control ffiDtw obtained by a map search or the like in accordance with the cooling water temperature TW of the engine 1 detected by the water wetness sensor 10, and the idle determination means 24 to detect the throttle fully open and control the idle state. The feedback control amount (for example, duty ratio) [) out which is calculated according to the deviation between the target engine speed N set corresponding to the cooling water temperature TV and the actual engine speed N when it is determined that the condition is In addition, the ISC valve 5 is controlled by the correction @[) et that is set according to the operating state of the air conditioner, the gear position, etc.
) out and control signal (duty signal) ISO
It outputs to valve 5. [) out = [) tw+ [) l+ [)et
Therefore, during load operation, feedback control ill ff
1DFB=O and ■SC valve 5 control [, [)ot
+t is approximately given by the basic control ff1DTW, and during idle, the control 0ffiDout is variably controlled by the feedback control 11ffiDFI'3 so that the engine speed N converges to the target engine speed Nset. When the idle state is detected in the idle determination means 23, the output signal T pbac from the basic fuel injection correction value calculation means 17 is used to set the basic fuel injection amount in the basic fuel injection m correction means 18. In addition to the basic fuel injection amount Tp set by means 16, the corrected basic fuel injection amount 1Tp -TI)'+T pbac
Calculate as Then, the basic fuel injection ff1Tp that has been corrected according to the change in the airflow flowing down the bypass passage 4 is given to the fuel injection amount setting means 20, and the air-fuel ratio correction value calculation means 21
The cooling water temperature F detected by the water temperature sensor 10 at
W, the air-fuel ratio correction value C0EF calculated according to engine operating conditions such as intake air temperature Ta detected by the intake air temperature sensor 12, and atmospheric pressure P detected by the atmospheric pressure sensor, and the air-fuel ratio in the feedback correction port calculation means. Feedback correction 51 calculated according to the output signal from sensor 14
1(rb), the fuel injection tAm Ti is set by the following formula, and the injector 8 is driven with a pulse width corresponding to this fuel injection mmTi to inject fuel. Ti = Tp x Kl x COEF Note that the above-mentioned fuel injection control The effect of the invention is shown in the flowchart of FIG.
Even when performing III m, the idle speed control valve controls the basic fuel injection amount determined from the engine speed and throttle opening! Since the correction is made based on I1m, a consistent air-fuel ratio can be obtained in all operating ranges, and correct fuel injection control can be achieved even at low revolutions, low loads, or when idling.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing one embodiment of the present invention, FIG. 2 is a block diagram of fuel injection amount control in a control unit, FIG. 3 is a flowchart showing the operation of fuel injection control, and FIG. The figure is a characteristic diagram of the air-fuel ratio sensor, and FIG. 5 is a map for determining the general basic fuel injection mTp. 3... Slot 1 to Le valve, 4... Bypass passage,
5...ISC valve, 6...Atmospheric pressure sensor, 8...
・Injector, 9... Throttle degree sensor, 10
...Water temperature sensor, 11...Crank angle sensor 1.1
2... Intake temperature sensor, 14... Air-fuel ratio sensor, 15
...Control unit, 16.. Basic fuel injection m setting means, 17.. Basic fuel injection & correction value calculation means, 18.. Basic fuel injection m correction means, 19.. Idle control means, 20. ...Fuel injection setting means. Patent applicant: Fuji Heavy Industries Co., Ltd. Agent: Patent attorney: Makoto Kobashi Ukiyo Patent attorney: Susumu Murai Figure 3

Claims (1)

[Claims] Idle calculates the control amount of the idle control valve that controls the idle engine speed of the engine, which is installed in the bypass passage that bypasses the throttle valve, so that the engine speed converges to the target idle engine speed set by the water temperature. In a fuel injection control device comprising a control means and a basic fuel injection amount setting means for setting a basic fuel injection amount from a throttle opening and an engine rotational speed, an idle determining means for determining an idle state from a throttle opening; Basic fuel injection amount correction value calculation means for calculating a correction value of the basic fuel injection amount according to the control amount output from the idle control means; and a correction value output from the basic fuel injection amount correction value calculation means during idling. 1. A fuel injection control device for an internal combustion engine, comprising: basic fuel injection amount correction means for applying to a basic fuel injection amount.