JPS59138736A - Fuel feeding apparatus for engine - Google Patents

Abstract

PURPOSE:To prevent generation of knocking without reducing output by increasing combustion pressure when knocking is generated. CONSTITUTION:When knocking is generated, large vibration is generated, and the output of a comparison circuit 78 forms a continuation of high-level signals. Therefore, the output of an integration circuit 80 becomes a large value enough to excite a combustion-pressure regulator 64, and combustion pressure increases. Therefore, atomization and evaporation of fuel are accelerated, and the temperature of intake gas is lowered, and knocking is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel supply device for a fuel injection engine.
In particular, it relates to the fuel pressure adjustment device.

BACKGROUND ART In fuel injection engines, in order to supply an appropriate amount of fuel, control has been conventionally performed to maintain a constant pressure difference between the fuel pressure at a fuel injection nozzle and the intake pressure near the nozzle. However, the required fuel supply level, fuel atomization, etc. change depending on the operating conditions, such as when cold, when accelerating and decelerating, when high/low load, when low/high speed, etc., so the differential pressure must be changed depending on the operating status. This is desirable.

Tokukai Show 3! ;-/No. 2.21.9 includes a fuel pressure regulator that maintains the differential pressure between the supplied fuel pressure and the intake pressure near the fuel outlet at a predetermined value, and also adjusts the supplied fuel pressure by the fuel pressure regulator to the operating state of the engine. A fuel supply device has been proposed that includes a fuel pressure correction means that corrects the fuel pressure accordingly. However, this publication does not specifically disclose how the fuel pressure is corrected depending on the driving state.

An object of the present invention is to provide a fuel supply system for an engine that can eliminate knocking by increasing the differential pressure between the fuel pressure and the intake pressure near the fuel injection position when non-knocking occurs.

The configuration of the present invention includes a fuel injector that injects and supplies fuel, a fuel pressure regulator that controls the fuel pressure of the fuel supplied to the fuel injector, and a pressure difference between the intake pressure and the fuel pressure at the fuel injection position of the intake passage. In the fuel injection type engine, the fuel injection type engine is provided with means for operating the fuel pressure regulator so that the pressure difference is increased, a means for increasing the differential pressure, a means for detecting knocking, and when non-king is detected by the knocking detecting means. The provision of a control means for operating the differential pressure increasing means is a % sign.

The present invention is equipped with a means for detecting non-king, and when non-king occurs, the pressure difference between the fuel pressure and the intake pressure can be controlled to increase. This promotes atomization and vaporization of the fuel, lowers the intake air temperature, and suppresses the occurrence of non-king.

In response to an increase in fuel pressure, the fuel injection time can be shortened to maintain a constant fuel supply amount, but even if the fuel pressure increases, it is not necessarily necessary to correct the injection time. Even if the fuel pressure is increased, if the fuel injection time is maintained at 1, the air-fuel mixture will become uniform, and the non-king prevention effect will be further enhanced.

When detecting knocking, since abnormal vibration occurs when non-king occurs, the occurrence of non-king can be detected by, for example, attaching a suitable vibration sensor to the side wall of the cylinder and detecting the vibration of the cylinder.

Conventionally, delaying the ignition timing has been carried out as a countermeasure against non-king, but if the ignition timing is delayed too much, it becomes difficult to avoid a drop in output. In the present invention, non-king can be suppressed by controlling the fuel pressure as described above.
Therefore, there is no need to delay the ignition timing,
Furthermore, even when a non-king countermeasure is taken by using a delay in ignition timing, the delay only needs to be adjusted by a small amount, and the engine output is not adversely affected.

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

FIG. 1 shows a schematic diagram of an engine E incorporating the fuel pressure control device of the present invention. Engine E has cylinder 1
0 and a piston 12 that slides within the cylinder 10, and a combustion chamber 14 is formed in the upper part of the cylinder 10. Is there an intake air in cylinder 12? - the boat 16.1B and the exhaust port 1B are open, and these boats 16.1B
includes an intake valve 20 and an exhaust valve 22 that open and close the hoard.
is provided. A spark plug 1γ is attached to the top of the combustion chamber so as to face downward. A knock sensor 19 is attached to the outer wall of the upper part of the cylinder to detect vibrations of the cylinder. Further, the intake port 16 has an intake passage 24,
Exhaust passages 26 are connected to the exhaust ports 18, respectively. An air cleaner 28 is installed at the upstream end of the intake passage 24.
An air flow meter 30 for measuring the amount of intake air is provided on the downstream side, followed by a supercharger 3 for supercharging the intake air downstream.
2 is provided. Furthermore, downstream of the supercharger 320, there is a throttle valve 34 that is operated in conjunction with the accelerator pedal.
, an intake negative pressure sensor 35 that detects intake negative pressure downstream of the throttle valve 34, and an injector 36 that injects and supplies fuel at a predetermined fuel pressure downstream thereof. The fuel in the fuel tank 38 is increased in pressure by the fuel pumper 40 and discharged into the passage 42, and then guided to the fuel injector 36.

The pressure of the fuel discharged into the passage 42 is regulated by a fuel pressure regulator 46.

As shown in FIG. 2, the fuel pressure regulator 46Fi is equipped with a diaphragm device 48, and a casing 50 of the diaphragm device 48 is partitioned by a diaphragm 52, and a passage 54 connects the intake passage 24 to the throttle valve 3.
4. A fuel chamber 58 is formed inside the fuel chamber 58, which communicates with the negative chamber 56 connected to the downstream side and the branch passage 44 from the fuel passage 42. A spring 60 is arranged in the negative pressure chamber 56 and the diaphragm 5
2 is biased to the left in the figure. - One end of the gun 60 is supported by a disc 62, and a pin 63 extending outward from the inside of the casing 50 is connected to the disc 62, and this pin 63 depicts the mover of the solenoid. . A solenoid coil 64 is provided in place of the bin 630, and when the solenoid coil 64 is energized, the bin 63 and the disk 62 are moved to the left in the figure. A return passage 45 to the fuel tank 38 protrudes from the fuel chamber 58, and its tip 66 is connected to the diaphragm 52.
It opens into the chamber 58 so as to face it. A part of the fuel discharged from the fuel pump 4o is guided into the fuel chamber 58 through the branched 7m path 44, and is connected to the diaphragm 52 and the light 146.
6 and return to the fuel tank 38.

The diaphragm 52 moves to the right in the figure when the pressure in the intake passage decreases. As a result, the gap 1d between the tip 66 and the diaphragm 52 becomes thick, and the tank 40
The amount of return to will increase. Therefore, the fuel pressure reflected in the injector 36 decreases. In this case, diaphragm 5
1j It moves in response to changes in the pressure in the intake passage, the differential pressure between the fuel pressure and the pressure in the intake passage is kept constant, and the fuel injection amount is determined by the opening time of the injector6. Also, when the solenoid coil 64 is deenergized, the bottle 6
3 moves to the left in the figure and strengthens the biasing force of the spring 6o, so the amount of fuel returned decreases and the fuel pressure increases.

A control unit 68 is provided to control energization and de-energization of the solenoid coil 64.

Referring again to FIG. 1, the control unit 68 calculates signals from the knock sensor 19, air flow meter 30, intake negative pressure sensor 35, and crank angle sensor 70, and sends the solenoid coil 64 to 1j! l
At the same time, it outputs an ignition timing control signal for the ignition plug 17 and an injection time, ie, injection amount control signal for the electromagnetic valve type fuel injector 36. Referring to FIG. 3, an example of circuit 07 of the control unit 68 is shown. control unit 68
I-i Fuel Ear 9Equipped with a basic/P pulse width setting circuit T2 that sets the injection time of the Ector 36.1This circuit γ2
Signals from the air flow meter 3o and the crank angle sensor TO are input to the circuit γ2, and the circuit γ2 performs predetermined calculations from these signals and outputs a pulse signal having a pulse width corresponding to the fuel injection time to the drive circuit γ4. Drive circuit 74
Fi, based on the signal from the basic pulse width setting circuit T2,
A command signal for opening and closing the fuel injector 36 is output. The control unit 68 includes a basic ignition timing setting circuit 76 that sets the ignition timing of the spark plug 1T, and the circuit T6 is connected to the crank angle sensor 70 and the intake negative pressure sensor 3
5, and outputs a signal corresponding to a predetermined ignition timing. This signal is input to the correction circuit 82.

The correction circuit 82 corrects the ignition timing if necessary and sends a signal to the output circuit 84. Based on the signal from the correction circuit 82, the output circuit generates a predetermined voltage at the spark plug 1T with a predetermined typing.

A signal corresponding to the thick peak of the vibration from the knock sensor 19 that detects engine vibration is input to a comparison circuit 78 . Comparison circuit 78 compares the signal with a set voltage corresponding to the set magnitude of vibration, and sets the signal to high level when the input signal from knock sensor 19 is large, and sets it to low level when the set voltage is large. generates a signal. This signal is input to an integrating circuit 80. The integration circuit 80 integrates the signal from the comparison circuit 78 and outputs the integrated signal to the solenoid coil 64 of the fuel pressure regulator 46 and the correction circuit 82. When knocking occurs, large vibrations occur and the comparator circuit continuously outputs a high level signal, so that an output is generated in the integrating circuit 80 and the solenoid coil 64 is energized. 1, the output of the integrating circuit 80 is
The signal is also input to the correction circuit 82, and the correction circuit 82 corrects the ignition timing to the delayed side based on the signal from the integration circuit 80, and sends the signal to the output circuit. That is, when non-king occurs, the ignition timing is corrected to be slightly delayed and inputted to the output circuit 84.

In the device having the above structure, when knocking does not occur, the signal value from the knock sensor 19 is small, so the output of the comparator circuit 7B is low level, and the output from the integrating circuit 80 is zero. In this case, the correction circuit 82 does not correct the /4' pulse signal of the ignition timing, and the signal from the basic ignition timing setting circuit 76 is input to the output circuit 84 as is. Further, the solenoid coil 64 of the fuel pressure regulator 46 is not excited, and the fuel pressure is maintained at a low value.

When knocking occurs, the output of the integrating circuit 80 becomes a large value as described above, and the correction circuit 82 corrects the signal from the basic ignition timing setting circuit 76 to delay the ignition timing according to the magnitude of the knocking.

As a result, the spark plug 1T ignites a little later than in the normal case. At the same time, the solenoid coil 64 is energized, the amount of fuel returned decreases, and the fuel pressure increases. This promotes atomization and vaporization of the fuel, lowers the intake air temperature, and eliminates knocking.In this example, since the intake air temperature decreases in this way, we rely on the operation to delay the ignition timing as a countermeasure for non-king. The fuel pressure decreases, the amount of delay can be reduced, and there is no problem of reduced output.Furthermore, since the fuel pressure is normally maintained at a low value, the fuel
The power consumption of 0 is small and there is no adverse effect on fuel efficiency, etc.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an engine fuel supply system according to an embodiment of the present invention, FIG. 2 is a detailed diagram of the fuel pressure regulator of FIG. 1, and FIG. 3 is a seven example of the control unit of FIG. 1. FIG. Explanation of symbols 10... Cylinder 12... Piston 14... Combustion chamber 16... Intake port 1T... Spark plug 18... ...
Exhaust port 19...Knock sensor +A,
20----Intake valve 22...Exhaust valve 2
4...Intake passage 26...Exhaust passage
28...Air cleaner 29...Exhaust temperature sensor 30...Air flow meter 32...Supercharger 34...Throttle valve 35... ...Intake negative pressure sensor v 36...
... Injector 38 ... Fuel tank 40
... Fuel pump 46 ... Fuel pressure regulator 64 ... Solenoid coil 68 ... Control unit 70 ...
・Crank angle sensor patent applicant Toyo Kogyo Co., Ltd.

Claims (1)

[Claims] a fuel injector for injecting and supplying fuel; a fuel pressure regulator for controlling the fuel pressure of the fuel supplied to the fuel injector; In a fuel injection engine, the fuel injection engine is equipped with means for operating a fuel pressure regulator, a means for increasing the differential pressure, a means for detecting non-king, and when the knocking detecting means detects knocking, the differential pressure increasing means is operated. 1. A fuel supply device for an engine, characterized in that it is equipped with a control means.