JPS63195356A - Fuel feeding device for engine - Google Patents

Abstract

PURPOSE:To prevent the mixture gas at the engine starting time from being overrich, by correcting the fuel injection quantity depending on the fuel leakage amount from an injection valve while an engine is stopped. CONSTITUTION:A control unit 15 arranged as a fuel injection quantity control device furnishes a correction device 26 to correct the fuel injection quantity depending on a normal injection pulse arithmetic device 21, a starting detecting device 23, a basic pulse width arithmetic device 24, an engine stopping time measuring device (a fuel leakage amount measuring device) 25, and the data from the measuring device 25. And the signals of an engine rotation frequency detecting sensor 16, a throttle opening sensor 17, and a water temperature sensor 18 are input thereto, the fuel injection quantity and the fuel injection timing are decided by the devices in the control unit 15, and the fuel is injected from an injector valve 14 by a driving device 22. By operating in such a way, the mixture gas is not made overrich, even though the fuel leaked while the engine is stopped is mixed with the injection fuel at the starting.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a fuel supply system for an engine equipped with a fuel injection valve, and particularly to measures against starting.

(Prior Art) Conventionally, a fuel supply system for an engine in which a fuel injection valve is provided in the intake passage of the engine and the amount of fuel injected from the fuel injection valve is electrically controlled is generally known. (Refer to Publication No. 54-14688). In this type of device, normally, when starting the engine, the fuel injection o1m is simply controlled to a preset value based on the engine water temperature and the like.

By the way, in this type of lit, the fuel injection valve is closed while the engine is stopped, but the sealing performance of the valve seat part of the fuel injection valve is not perfect, and the fuel injection valve is not applied to the fuel injection valve while the engine is running. As the fuel pressure remains in the fuel passage for a certain period of time even after the engine has stopped, fuel leaks from the fuel injector and accumulates in the intake passage.
This fuel leak ring changes depending on the engine stop time and other factors.

For this reason, in conventional devices that set the fuel injection 1111 without considering fuel leakage while the engine is stopped,
By the amount of fuel accumulated in the intake passage due to the fuel leak mentioned above,
When the engine is started, the air-fuel mixture supplied to the engine becomes overrich, which may deteriorate startability.

(Object of the Invention) In view of the above-mentioned circumstances, the present invention has been developed to prevent deterioration of startability even when the engine is started with fuel accumulated in the intake passage due to fuel leakage from the fuel injection valve while the engine is stopped. An object of the present invention is to provide an engine fuel supply device that can prevent such problems.

(Structure of the Invention) The present invention provides a fuel supply @ company for an engine equipped with a fuel injection valve and a control device for controlling the amount of fuel injection OI from the fuel injection valve. A basic injection amount setting means for setting the basic injection amount, a means for checking information related to fuel leakage from the fuel II valve when the engine is stopped, and a fuel injection amount based on the fuel leakage when the engine is stopped. This is provided with a correction means for correcting.

With this configuration, the fuel injection m is adjusted according to the amount of fuel leakage so that the air-fuel mixture supplied to the engine does not become overrich when the engine is started.

(Example) FIG. 1 shows an example of the present invention, and in this figure, 1
is an engine, and an intake boat 4 and an exhaust boat 5 are opened in a combustion chamber 3 formed above a piston 2 of the cylinder, and these intake boats 4 and exhaust boats 5 are connected to an intake valve 6 and an exhaust valve. 7, each of which is opened and closed at a predetermined timing. The intake boat 4 and the exhaust boat 5 communicate with an intake passage 8 and an exhaust passage 9, respectively.

The upstream end side of the intake passage 8 is connected to an air cleaner 10, and air 7 is connected to the intake passage 8 in order from the upstream side.
0-meter 11, throttle valve 12, surge tank 13
is provided, and a fuel injection valve 14 is provided near the intake boat 4. This fuel injection valve 14 is operated by a control unit (control unit 1) using a microcomputer or the like.
5, the fuel injection amount and fuel injection timing are set to t1.
11' is controlled. The control unit 15 includes an intake air amount detection signal from the air flow meter 11, a signal from the engine speed detection sensor 16, a signal from the throttle opening sensor 17 that detects the opening of the throttle valve 12, and engine cooling water. Various signals necessary for control, which will be described later, are inputted, such as a signal from a water temperature sensor 18 that detects S degrees, a signal from an intake temperature sensor 19, and a battery voltage vb.

FIG. 2 shows each means included in the $131 unit 15. The control unit 15 includes a means 21 for controlling the injection pulse width according to the intake air amount, engine speed, etc. during normal operation, and a means 21 for controlling the fuel injection pulse width. A driving means 2 that outputs an injection pulse to the valve 14 to inject fuel for a time corresponding to the injection pulse width.
2, and a means for controlling "fuel injection at the time of engine start determined by the start determination means 23." This means for controlling the fuel injection amount at the time of engine starting includes a basic 1111J1 pulse width calculating means 24 that calculates the basic injection pulse width according to the engine water temperature, and a means for controlling the amount of fuel leaked from the fuel injection valve 14 when the engine is stopped. The measuring means 25 measures the engine stop time as a means for checking information about the engine stoppage, and the correcting means 26 corrects the fuel injection t14II according to the information from the measuring means 25. In this embodiment, in addition to the correction according to the information related to the fuel leakage, the correction means 26 also performs correction according to the wetness (fuel adhesion) of the intake passage wall that changes depending on the water temperature, and correction when the engine is stopped. Corrections are also made in response to evaporation of fuel in the intake passage.

FIG. 3 shows a specific example of control by the #A control unit 15 in the form of a flowchart. - In this flowchart, when starting, first, in step S1, the engine stop time Tx measured by the engine stop time measurement timer is read. Then, the processes of steps 82 to S15, which will be described later, are repeated as long as the determination as to whether or not the engine is to be stopped based on the ignition signal etc. in step Sm is No (the engine is in operation), and when the engine is stopped, the timer is activated. and start it up (step S17゜S
m). The timer operates while the engine is stopped, so the time Tx read in step S1 when the engine is running is the time from when the engine is stopped until the next time when the engine is started.

In step 82 and S3, the battery voltage vb and engine water ITHW are read, and in step S4, the engine operating state is detected based on the intake air amount, engine speed, throttle opening, etc. Subsequently, in step S5, the invalid injection pulse width τ corresponding to the invalid injection time of the fuel injection valve 14,
is calculated as a value f (Vb) corresponding to the battery voltage (■b).

Next, in step S6, it is determined whether or not the engine is being started, for example, when the starter is operating and the engine speed is below a predetermined value.

When this determination result is YES, as fuel control during engine starting, first in step S7, the Noromoto injection pulse width τ
. is calculated as 110 (T to IW) corresponding to water 11THW. Subsequently, in step S8, a wet correction mτ which corrects the amount of fuel injection tI4M to an extent commensurate with the wetness of the intake passage wall when the engine is stopped is calculated as a value 11 (THW) corresponding to the water temperature THW. Next step S9
Then, the leakage correction [-, which corrects the reduction of the fuel injection 01m to the extent that it corresponds to the fuel leakage peak from the fuel injection valve 14 while the engine is stopped, is changed to 1ili (T) according to the engine stop time TX.
x). Furthermore, in step Sη, an evaporative correction amount τ is set to a value va according to the engine stop time Tx, which is used to reduce the above-mentioned reduction correction to an extent commensurate with the evaporative amount of fuel in the intake passage when the engine is stopped. (Tx). and step S
11, the basic fuel injection pulse width τ. and each correction amount, the injection pulse width τ5 is calculated as [τ8−τ.

−τ −τ +τ ], and in step 512W
6 eva , the final 1II9A pulse width τ1 is calculated by adding the invalid injection pulse width τ to the injection pulse width τ5.

Then, the process moves to step S13, where the fuel injection valve 14 is driven with the final injection pulse width τ, and then step S11
If it is determined in step S1 that the engine is not stopped, the process returns to step S2. Note that if the determination result in step Ss is No after the engine is started, as normal control, in step S14, for example, the injection amount is determined according to the intake air amount and the engine rotational speed, at the time of afA load, at the time of acceleration, etc. The fuel injection pulse width τ8 corresponding to the operating condition is calculated based on the correction amount corresponding to the above fuel injection pulse width τ8 in step S15. The final fuel injection pulse width τi is obtained by adding the invalid injection pulse width τ to
After obtaining , the process moves to step So.

In the fuel 'an processing at engine startup in the above flowchart (steps 87 to 512), the basic injection pulse width is determined according to the water temperature T HW when the intake passage is sufficiently dry (no fuel adhering). requested fuel injection fAm
It is calculated based on data experimentally investigated in advance to match the above, and as shown in FIG. 4 <a>, it is set to a large value when the water temperature is low, and is set to a small value when the water temperature is high. The wet correction amount τW is set according to the water tlT)IW as shown in FIG. 4(b). In other words, the degree of wetness of the intake passage when the engine is stopped changes depending on the amount of fuel injected when the engine is running, and increases at low temperatures when the air-fuel ratio is richly corrected, so the amount of fuel injected when starting the engine is reduced accordingly. Thus, the wet correction amount τW is increased on the low temperature side.

Further, the leak correction amount τg is set according to the engine stop time as shown in FIG. 4(C). In other words, after the engine is stopped, the fuel pressure remaining in the fuel passage connected to the fuel +1mrA valve gradually decreases over time, but while this fuel pressure is high, fuel leaks from the fuel injection valve, and when the fuel pressure decreases, fuel leaks. Therefore, within a predetermined time during which fuel leakage occurs, the leak correction amount τQ is increased as the engine stop time becomes longer, and when the engine stop time becomes longer than the predetermined time, the leak correction amount τa is kept constant.

Further, the evaporative correction -τ is set according to the engine stop time as shown in FIG. 4(d). In other words, as the engine stop time improves, the fuel remaining in the intake passage when the engine is stopped, which is a factor in the wet correction mentioned above, and the fuel in the intake passage due to fuel leakage, which is a factor in leak correction, will gradually evaporate. A direction that cancels out the fuel reduction correction as the stop time increases (
The evaporative content correction amount τ va is increased in the direction of increasing the fuel injection amount. However, the evaporation correction amount τeva is made not to become larger than the correction amount in the W fuel reduction direction due to the wet correction -τ and the leak correction [-.

According to the device of this embodiment, when the engine is started, the injection pulse width τS (corresponding to the fuel injection amount) determined in step S11 of the above flowchart is determined as shown in FIG. 5 according to the engine stop time up to that point. controlled by. In other words, when the engine stop time is close to O, the basic injection pulse width is τ.

The value obtained by subtracting the wet correction lτ9 from the above is the ejection pulse width τ6. If the engine stop time is extended until the fuel pressure in the fuel supply passage is sufficiently reduced, the leak correction amount τa increases to match the amount of fuel leaking from the fuel injection valve 14, so that the injection pulse width τ
6 becomes smaller, and the fuel injection amount decreases. Furthermore, as the engine stop time becomes longer, the evaporation correction amount τ that counteracts the reduction in fuel gradually increases to match the evaporation of fuel in the intake passage, so the above *va pulse width τS becomes larger. The basic injection pulse width is τ. approach.

In this way, the fuel injection amount at the time of starting the engine is corrected and controlled according to the fuel remaining in the intake passage due to fuel leakage from the fuel injection valve 14 when the engine is stopped, and thereby the fuel injection amount is controlled to be corrected when the engine is started. will be adjusted in due course.

In the above embodiment, the engine stop time is investigated as information related to fuel leakage M while the engine is stopped.
In addition to this, residual fuel pressure, etc. may also be checked.

(Effects of the Invention) As described above, the present invention examines information related to the amount of fuel leaking from the fuel injection valve while the engine is stopped and corrects the amount of fuel injection at the time of starting the engine accordingly. Even if the fuel accumulated in the intake passage due to fuel leakage is supplied to the engine together with the fuel injected from the fuel injection valve when starting the engine, this prevents the mixture from becoming overrich and improves engine startability. can be kept in good condition.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing means included in a fuel injection valve control tIl device, FIG. 3 is a flowchart of Illtm, and FIG. 4 (a
) to (d) are diagrams showing the basic injection pulse width and various correction amounts when starting the engine, and FIG. 5 is a diagram showing the relationship between the injection pulse width corresponding to the corrected fuel injection amount and the engine stop time. DESCRIPTION OF SYMBOLS 1... Engine, 8... Intake passage, 14... Fuel injection valve, 15... Control unit, 24... Basic injection pulse width calculation means at the time of engine starting, 25... Engine stop time Measuring means (means for checking information related to the amount of fuel leaking from the fuel injection valve while the engine is stopped), 26...
・Correction means. Patent applicant Mazda Co., Ltd. Agent
People Patent Attorney Etsushi Kosho
Chief Patent Attorney 1) Patent Attorney 1
Blackboard Qinfu Figure 1

Claims (1)

[Claims] 1. In a fuel supply system for an engine that includes a fuel injection valve and a control device that controls the amount of fuel injected from the fuel injection valve, a basic injection amount that is set in the control device after the basic injection at the time of starting the engine. A setting means, a means for checking information related to the amount of fuel leaking from the fuel injection valve when the engine is stopped, and a correction means for correcting the fuel injection amount based on the amount of fuel leaking from the fuel injection valve when the engine is stopped. An engine fuel supply device featuring: