JPS6217330A - Fuel supply device for engine - Google Patents

Abstract

PURPOSE:To eliminate the worsening of exhaust emission and also enable the fuel consumption performance to be improved by providing a means for the reduction and correction of the quantity of fuel supply to an engine after its complete combustion in response to the cranking time. CONSTITUTION:Fuel is injected by a fuel injector 5 which is controlled by ECU 9. The quantity of intake air is controlled by a throttle valve 6, and, when the engine is in the idling state, the intake air having passed through an airflow meter 2 is adjusted through a by-pass passage 7 by a solenoid valve 8. The solenoid valve 8 is controlled in response to the duty factor of a control pulse signal from ECU 9. Said ECU 9 is provided with both a cranking detecting means for detecting the cranking time of an engine and a means for the reduction and correction of the quantity of fuel supply to the engine in the state of idling operation within a fixed period of time after its complete combustion in response to the cranking time detected by said detecting means. Thereby, a fuel injection pulse F is fed with these information so as to enable a stable air-fuel ratio to be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fuel supply device for an engine.

(Prior art) Conventionally, in an electronically controlled engine fuel supply system,
Especially the engine start! For example, as shown in Fig. 6, fuel supply during gr is performed by applying a fuel injection pulse to the fuel injector with a pulse width corresponding to the engine cooling water temperature, and especially when the water temperature is low. The fuel increase value increases with time (for example, see Japanese Patent Laid-Open No. 139830/1983). Therefore, according to such conventional technology, the amount of starting fuel is determined only by the cooling water temperature at that time, regardless of the cranking time from when the engine is started, that is, when the starter switch is turned on until the engine completely explodes. Become. and,
Once the engine has completely exploded, a transient correction is made to the amount of fuel in the idle state after the complete explosion, but in this case as well, the amount of fuel to be supplied is determined based on the temperature of the cooling water. ing.

However, the cranking time is not constant and varies considerably depending on the starting condition. Therefore, even if the engine speed during cranking (e.g., 300 rpm) is constant, the air in the engine combustion chamber immediately after the engine completely explodes will vary depending on whether the cranking time is 3 seconds or 5 seconds, for example. There is a considerable difference in the fuel ratio (A/F>), and the wetness of the spark plug part also differs greatly.As a result, in this state, as in the conventional technology described above, after complete explosion, the When determining the amount of idle fuel to be supplied to the exhaust gas, the optimum air-fuel ratio cannot be obtained, and the combustion state becomes unstable, resulting in a rough idle.In addition, the air-fuel ratio of the exhaust gas supplied to the exhaust purification device is also high. The concentration increases, leading to deterioration of exhaust emissions.Furthermore, unnecessarily making the air-fuel ratio rich causes various problems such as deterioration of fuel efficiency.

(Object of the Invention) The present invention has been made to improve the above problem, and the above problem is solved by reducing the amount of fuel supplied according to the cranking time after the engine has completely exploded. The object of the present invention is to provide a fuel supply device for an engine.

(Means for achieving the object) In order to achieve the above object, the engine fuel supply system of the present invention, as illustrated in FIGS. 1 and 2, is based on the amount of intake air to the engine. The engine fuel supply device supplies a predetermined amount of fuel to the engine by correcting it with a predetermined correction signal depending on the operating state, comprising a cranking time detection means for detecting the cranking time of the engine; A reduction correction means is provided for reducing the amount of fuel to be supplied in an idling state within a predetermined period of time after the engine has completely exploded in accordance with the cranking time detected by the ranking time detection means.

(Function) According to the above means, the amount of fuel supplied is arbitrarily reduced during a predetermined period of time after the engine has completely exploded, depending on the cranking time up to that point. Therefore, it is possible to appropriately compensate for the difference in the air-fuel ratio immediately after complete combustion due to the difference in cranking time in the idle state, and it is possible to always obtain a stable air-fuel ratio regardless of the difference in cranking time. Not only does the idle speed become more stable, there is no deterioration in exhaust emissions, and fuel efficiency is also improved.

(Example) 11th ii! ! FIGS. 1 to 5 show a fuel supply system for an engine according to an embodiment of the present invention.

First, the outline of the control system of the apparatus according to the embodiment of the present invention will be explained with reference to FIG. 1, and then the control of the main parts will be explained.

In Fig. 1, reference numeral 1 indicates the engine body, where intake air is taken in from the outside via an air cleaner, and then supplied to each cylinder via an air flow meter 2 and a throttle chamber 3, and fuel is supplied to each cylinder by the ECU 9 as described later. The fuel is injected by a controlled fuel injector 5. The amount of intake air into the cylinder is controlled by a throttle valve 6 provided in the throttle chamber 3, and the amount is detected by an air flow meter 2. The throttle valve 6 is linked to the accelerator pedal, and is maintained at a minimum opening degree in an idling state.

On the other hand, the throttle chamber 3 is provided with a bypass passage 7 that bypasses the throttle valve 6.
This bypass passage 7 is provided with a solenoid valve (calibration valve) 8 which serves as an air amount adjusting means for controlling the engine speed during idling. Therefore, in the idling state, the intake air that has passed through the air flow meter 2 is transferred to the bypass passage 7.
It is supplied to each cylinder via the solenoid valve 8, and the amount of supply is adjusted by the solenoid valve 8. The opening/closing state of this electromagnetic valve 8 is controlled by the duty ratio of a control pulse signal supplied from an engine control unit (hereinafter abbreviated as ECU) 9.

On the other hand, the fuel injector 5 has a filter 16
and fuel tank via fuel pump 15! Connected to 4. Reference numeral 17 is a pressure regulating valve provided on the return side of the fuel supply line.

The ECU 9 is configured to include, for example, a microprocessor (CPU) at its center, memory (ROM and RAM), and an interface (Ilo) circuit. The above-mentioned interface circuit of this ECU 9 includes, for example, an engine starting signal S when the starter switch (ST switch 3 is turned on), a detection signal T of the cooling water temperature of the engine body I detected by a thermistor, a throttle signal detected by a potentiometer, etc. Opening degree signal TV of valve 6
O, the intake air amount detection signal Q detected by the air flow meter 2, and the crank angle signal C detected by the crank angle sensor 12 are each manually input.

A portion of the fuel in the fuel tank 14 is supplied to the fuel injector 5 via the filter 16 by the fuel pump 15 as described above, and the fuel is supplied to the ECU 9.
The fuel injection pulse F supplied by the fuel injection pulse F. is supplied to the engine from the fuel injector 5, while other excess fuel passes through the pressure regulating valve 17 to the fuel tank I4.
will be returned to. The above fuel injection pulse F. is generally calculated based on the following equation.

Fo=Fp”α(+ +KI+, to 2+ to 3+ to 4)K
F C・Ko+Fs ... (1) However, Fp: Basic injection pulse α: Air-fuel ratio feedback correction value 1: Start-up increase correction value 2: Water temperature correction value (for low water temperature) K3 After near idling increase correction Value: 4: Air-fuel ratio correction value KFC: Fuel cut correction value KD: Reduction correction coefficient (relative to cranking time) Fs: Voltage correction value Note that the code 10 indicates an exhaust pipe equipped with a three-way catalytic converter 11. ing.

Next, the control operation of the above control device will be explained in detail with reference to FIG. 2.

When the control operation is first started, the various input information described above, namely, the crank angle signal C1, the intake air amount signal Q, the engine start signal S, and the engine coolant temperature signal T are read at predetermined time intervals. (Step S,
), then the ON state of the starter switch (ST switch) is determined based on the human power state of the engine start signal S (step S2). If this judgment result is YES,
That is, when the engine is in the starting state, first, the starting fuel is injected (step S , ) are performed. In addition,
The correction amount of the starting fuel is reduced when the operating state is at a predetermined water temperature (for example, 10° C.) or higher and the idle contact is turned on, that is, when the idle region is reached (transient increase N).

On the other hand, if the starter switch is OFF (No in step S), the process further proceeds to step S to determine the previous ON/OFF state of the starter switch. If the answer is YES, which is currently OFF but was previously ON, that is, when the engine is starting and is in a cranking state (engine speed is approximately 30 Orpm), first, the fuel increase rate (water temperature A correction value) K is calculated (step S,), and further step S. A predetermined correction coefficient Ko corresponding to the cranking time is calculated.

As already explained in the prior art section, the air-fuel ratio (A/F) in the combustion chamber immediately after complete explosion differs depending on the cranking time, so this correction coefficient KO is calculated immediately after complete explosion according to the cranking time. This is to correct the fuel injection amount at idle by a predetermined amount (separate from the original idle correction), and as shown in Figure 3, the coefficient value can be changed according to the cranking time t. ing. and,
In the next step S7, a time a for performing the correction is calculated according to the engine rotational speed during cranking, and the set time a of the control time setting timer TM based on the correction coefficient Ko is set to a. This set time a is set corresponding to the detected value from the cranking time detecting means of the engine. On the other hand, in step S3, if the starter switch was previously turned off (NO), that is, if cranking was completed, first, in step S8, the fuel increase rate is calculated according to the water temperature T at that time, and then in step S , the fuel increased by 2 to the increase rate is injected as the amount of fuel to be supplied during idling.

Next, when the control time a is set in step S7, it is determined in step 610 that TM=O1, that is, the elapse of the set time a. If this judgment result is No, that is, within the set time a, step S11
Then, fuel is injected at an increase value of K o Then, proceeding further to step SI2, the time of the timer TM is sequentially counted down (TM-1).
and repeat step S until the time is up completely. ~
Continue the operation of Stt. Therefore, the above steps S, ~
By the operation S+t, the amount of fuel supplied to the engine in the idle state immediately after a complete explosion is corrected to an appropriate amount according to the cranking time t (see FIG. 4). On the other hand, when the result of the judgment in step S+o is TM=O1, that is, the set time a has elapsed, the correction coefficient Ko is gradually returned to 1, and fuel is injected at an increase rate of K o X K t (step 513).

The above steps 88 to S7 and step S. ~S1
As a result of the control operation in step 1, the amount of fuel supplied in the idling state after the engine has completely exploded is corrected according to the cranking time as shown in the characteristics in Figure 4, and for example, in response to the water temperature as shown in Figure 5. , and the final increase rate (K v = K o ·K,) is determined such that the larger the cranking time t is, the smaller the amount is, and the smaller the cranking time t is, the larger the amount is.

(Effects of the Invention) As explained above, the engine fuel supply device of the present invention corrects the intake air amount to the engine based on the amount of intake air to the engine using a predetermined correction signal according to the operating condition. A fuel supply device for an engine that supplies a predetermined amount of fuel includes a cranking time detection means for detecting a cranking time of the engine, and a cranking time detection means for detecting a cranking time of the engine. The present invention is characterized in that it is provided with a reduction correction means for reducing the amount of fuel to be supplied in the time idle state.

Therefore, according to the present invention, the amount of fuel supplied is arbitrarily reduced during a predetermined period of time after the engine has completely exploded, depending on the cranking time up to that point. Therefore, it is possible to appropriately compensate for the difference in the air-fuel ratio immediately after complete combustion due to the difference in cranking time in the idle state, and it is possible to always obtain a stable air-fuel ratio regardless of the difference in cranking time. Not only does the idle speed become more stable, there is no deterioration in exhaust emissions, and fuel efficiency is also improved.

[Brief explanation of the drawing]

FIG. 1 is a control system diagram of an engine fuel supply device according to an embodiment of the present invention, FIG. 2 is a flowchart showing the control operation of the device according to the embodiment, and FIG. 3 is a control operation of the above-mentioned FIG. 2. 4 is a graph showing the relationship between the cranking time and the correction coefficient for the cranking time, FIG. 4 is a graph showing the relationship between the fuel increase rate and the cranking time in the control operation of FIG. 2, and FIG. FIG. 6, which is a time chart showing the effects of the present invention, is a graph showing the fuel injection pulse width characteristics at the time of conventional starting. 1...◆Engine body 2...Air flow meter 5...Fuel injector 6...
Throttle valve 7 ... Bypass port 8 ... Solenoid valve 8 9 ... Engine control unit 13 ...
...Starter switch 14...Fuel tank applicant Mazda Co., Ltd. agent Patent attorney -*-oka

Claims (1)

[Claims] 1. In an engine fuel supply system that supplies a predetermined amount of fuel to the engine by correcting the intake air amount to the engine using a predetermined correction signal according to the operating condition, the cranking time of the engine is adjusted. A cranking time detection means for detecting the cranking time, and a reduction correction means for reducing and correcting the amount of fuel to be supplied in an idle state within a predetermined time after the engine complete explosion according to the cranking time detected by the cranking time detection means. An engine fuel supply device characterized by: