JPH0216362A - Fuel feed device of engine - Google Patents

Abstract

PURPOSE:To maintain the pressure reduction of a fuel constant by amplifying a venturi negative pressure by a fuel regulator to regulate the fuel pressure, and introducing the fuel pressure to a regulating chamber of the fuel regulator and a pressure governing chamber in a fuel pressure correction mechanism simultaneously to offset each other. CONSTITUTION:A fuel regulator 13 controls a fuel pressure corresponding to a venturi negative pressure with the opening of a control valve 23 driven by each diaphragm 17, 19, 21 partitioning a fuel chamber 16, a negative pressure chamber 18, an atmospheric chamber 20 and a regulating chamber 22. A fuel pressure correction mechanism 14 is provided, which has a valve body 39 for regulating the fuel pressure driven by a displacing member 30 partitioning a pressure governing chamber 28 and a back chamber 29 formed between the weighing part 35 of a fuel passage 10 and a fuel injection port 12. A correction fuel passage 34 branched from the upper stream side than the fuel regulator 13 of the fuel passage 10 and reached to the back chamber 29 through the regulating chamber 22 is provided. The pressure reduction in the lower stream side than the fuel regulator 13 of the fuel passage is maintained constant by the fuel pressure correction mechanism 14.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an apparatus for supplying fuel to engines, primarily automobile gasoline engines.

[Prior Art] The applicant of this patent has proposed a fuel supply method in which the venturi negative pressure is first amplified, the fuel pressure is controlled in response to this amplified negative pressure, and the controlled fuel is injected into the intake passage. proposed a device (
Special) Gansho 58-91738.95326, 152654
, No. 161053.207263, patent application 1986-486
No. 60, Patent Application No. 1988-241189, Patent Application No. 1987-3
2551.96230.24254G, 211 ] ]
84. Jitsugan Sho 62-62162, etc.).

The fuel supply devices shown in the inventions and devices related to these earlier applications will be schematically explained based on FIG. 3. The venturi 51.
52, a fuel passage 57 which pressurizes the fuel in the fuel tank 54 by the fuel pump 56 and sends it to the injector 55 provided in the venturi 52, and this fuel passage 57.
It is equipped with a fuel regulator 62 having a fuel chamber 60 and a negative pressure chamber 61 arranged in the middle and partitioned by two diaphragms 58 and 59, and a venturi negative pressure path 63 connected to the negative pressure chamber 61. The led venturi negative pressure is amplified by two diaphragms 58 and 59 having different effective diameters, the control valve 64 is operated, and the fuel pressure is adjusted by controlling the amount of fuel returned to the return passage 65.

That is, when such a fuel regulator 62 is used, the fuel pressure is adjusted by amplifying the venturi negative pressure generated in accordance with the amount of intake air. In addition to being able to measure output, it is also possible to adjust the fuel pressure even in a region where the amount of intake air is relatively small, and since the fuel pressure is adjusted in response to the negative and positive venturi, the air-fuel ratio is almost constant over the entire operating range of the engine. It has the advantage of being constant.

However, in the low opening range of the throttle valve 66, the amount of intake air is extremely small, so the venturi negative pressure is low, and even if this is amplified, the movement of the control valve 64 is small and the pressure cannot be adjusted to an appropriate level corresponding to the amount of intake air. I can't. Therefore, a variable metering section 67 is provided in the fuel passage 57 on the downstream side of the fuel regulator 62, and the effective area of the fuel passage 57 is changed by mechanically or electrically interlocking with the throttle valve 66.
It was also proposed that the fuel supply temperature should be adjusted to correspond to 1JFJ degree of 6.
-94249).

[Problems to be Solved by the Invention] However, in the operating range of the throttle valve 66 other than the low opening range, the
When the first part 67 is fully opened, the fuel adjusted by the fuel regulator 62 is depressurized and injected by the throttle resistance of the part 67 and the pipe resistance of the fuel passage 57, so that the total is 1+.

There would be no problem if this pressure drop remained constant regardless of changes in the amount of intake air, but in reality, as the amount of intake air increases, this pressure drop also increases, so it does not correspond accurately to the amount of intake air. There is a problem in that it is not possible to obtain a certain fuel pressure.

[Means for solving the problem] An intake passage having a venturi;
a fuel passage opened in the intake passage for feeding and injecting fuel; a fuel chamber formed in the middle of the fuel passage; a negative pressure chamber into which venturi negative pressure is introduced; and an atmospheric chamber open to the atmosphere. It has an adjustment chamber into which regulated fuel is introduced, and a control valve driven by three diaphragms that partition these four chambers, and the opening degree of this control valve corresponds to the venturi negative pressure. a fuel regulator that controls fuel pressure; a pressure regulating chamber formed in a portion of the fuel passage between the metering section and the fuel nozzle; a back chamber; and a displacement member that partitions the two chambers. ,
a fuel pressure correction mechanism having a valve body that is driven by the displacement part set and adjusts the fuel pressure reaching the fuel nozzle; branching from the upstream side of the fuel regulator in the fuel passage and passing through the adjustment chamber to the back chamber; and a correction fuel passage leading to the fuel pressure adjustment mechanism, the fuel pressure correction mechanism is configured to maintain a constant pressure drop on the downstream side of the fuel regulator in the fuel passage. did.

[Function] The venturi negative pressure generated in response to the amount of intake air is amplified by the fuel regulator to adjust the fuel pressure, and the fuel pressure, which increases in proportion to the increase in the amount of intake air, is compensated for by the fuel passage. By introducing the air into the adjustment chamber and the pressure adjustment chamber of the fuel pressure correction mechanism at the same time to cancel each other out, the pressure drop caused by the increase in intake air amount is kept constant.

[Implementation example] Embodiments of the present invention will be described with reference to the drawings.

In Figures 1 and 2, reference numeral 1 denotes an intake body having an intake passage 2, 3 and 4 two large and small venturis formed in the intake passage 2, 5 a throttle valve provided in the intake passage 2, and 6 a fuel tank. ,
Reference numeral 8 indicates a fuel pump driven by the prime mover 7; 10 indicates a fuel passage for sending fuel pressurized by the fuel pump 8 to a fuel nozzle 12 opened in the intake passage 2 of the injector 11;
3 shows a fuel regulator according to the present invention disposed in the middle of the fuel passage 10. As shown in FIG.

The fuel regulator 13 includes a fuel chamber 16 provided in the middle of the fuel passage 10 and the fuel chamber 1 with a first diaphragm 17 in between.
6, an atmospheric chamber 20 provided on the opposite side of the negative pressure chamber 18 with a second diaphragm 19 in between and open to the atmosphere, and a second diaphragm 21 in between. An adjustment chamber 22 provided on the opposite side of the atmospheric chamber 20
The first diaphragm 17 has a control valve 23 for changing the effective area of the return passage 15 connected to the fuel tank 6.
A second diaphragm 19 having a larger effective area than the first diaphragm 17 and a third diaphragm 21 having the same effective area as the first diaphragm 17 each have two diaphragms 17.
It is constructed by fixing arms 24 and 25 that maintain a constant spacing between 19 and 21 and operate them integrally. A venturi negative pressure path 26 that opens at the narrowest part of the smaller venturi 4 is connected to the negative pressure chamber 18 .

The injector 11 is installed in the larger venturi 3 and has a fuel nozzle 12 that opens downward in the intake passage 2 and an air nozzle 31 that opens around the fuel nozzle 12.
It has an integrated structure.

The fuel pressure correction mechanism 14 includes a pressure regulating chamber 28 disposed in the middle of the fuel passage 10 slightly upstream of the fuel nozzle 12;
A back chamber 29, a displacement member 30 consisting of a bellows (or diaphragm, etc.) that partitions these two chambers 28, 29,
The valve body 39 is fixed to the displacement member 30 and changes the effective area of the outlet 28a of the pressure regulating chamber 28 to the fuel nozzle 12, and the fuel pressure guided to the pressure regulating chamber 28 and the fuel pressure guided to the fuel pressure 29 in the back chamber are controlled. By displacing the displacement member 30 to the equilibrium position, the effective area of the outlet 28a is changed by the valve body 39 interlocked with the displacement member 30 to adjust the fuel pressure reaching the fuel injection port 12, thereby adjusting the amount of fuel injected from the valve body 39.

Further, it branches from the flow side of the fuel chamber 16 of the fuel passage 10 and reaches the fuel tank 6 via the shet 32, the adjustment chamber 22 of the fuel regulator 13, the back chamber 29 of the fuel pressure correction mechanism 14, and the pressure regulator 33. A correction fuel passage 34 is provided.

Fuel chamber 16 pressurized to a constant pressure by fuel pump 8
P l + Negative pressure in negative pressure chamber 18 P2 + Pressure in atmospheric chamber 20 P 3 + Fuel pressure in adjustment chamber 22 P 4 + Effective area of first, second and third diaphragms 17.19.21 are Δ, B, and C, respectively, then P,=-((B/
A)-1) ・P2+(B C)/A-P3
The relationship +C/A-P4 is established. Here, P3 is the atmospheric pressure, and since A and C are equal, P, = -((B/A)-1) ・P2+P4. As a result, the negative pressure chamber 18 corresponding to the venturi negative pressure
The negative pressure P2 of -((B/A
) -1) It can be seen that the pressure is amplified twice and reversed to positive pressure to adjust Pl.

That is, if P4 is constant, when P2 is low, control valve 2
When the opening degree of 3 is large, a large amount of fuel is released into the return passage 15 to the fuel tank 6, lowering Pl. 1Conversely, when P2 is high, the opening degree of the control valve 23 is small and the amount of fuel released is reduced, resulting in a decrease in Pl. , it increases.

In this way, even if Pl is adjusted in accordance with P2, if the resistance of the metering section 35 located downstream of the fuel chamber 16 and the pipe resistance of the fuel passage 10 are not constant, the flow from the fuel nozzle 12 will be reduced. The fuel injection amount does not meet the required value. However, in reality, as the amount of intake air increases, that is, as Pl increases, these resistances also increase, and the pressure of fuel injected from the fuel nozzle 12 does not increase in response to the increase in the amount of intake air, and the amount of fuel supplied decreases. It will no longer correspond to the amount of air.

According to this embodiment, when the intake air amount increases, the fuel pressure P4 of the fuel flowing into the adjustment chamber 20 from the correction fuel passage 34 also increases. Since P4 is also guided from the passage portion 34a of the correction fuel passage 34 to the back chamber 29 of the fuel pressure correction mechanism 14, the fuel pressure P1 in the pressure regulation chamber 28 of the fuel pressure correction mechanism 14 increases in synchronization with the rise in Pl.
．． increases, the fuel pressure in the back chamber 29 P4. will also rise. Therefore, the shortfall in P, ie, the pressure drop, can be offset against the pressure rise that should correspond to the increase in the amount of intake air, so that it remains constant. Furthermore, the fuel pressure P4. is the displacement member 30
Although it is set by the effective area and elastic force of the pressure regulator, it can also be set by the shet 32 and the pressure regulator 33. Further, the fuel that has entered the back chamber 29 is returned to the fuel tank 6 from the passage portion 34b of the correction fuel passage 34 via the pressure regulator 33.

The pressure-adjusted fuel is injected from the fuel nozzle 12 at the same time, and the pressurized air generated by the air pump 9 which is simultaneously driven by the prime mover 7 and the fuel pump 8 is placed in the middle of the air passage 36. The air is adjusted to a constant pressure by the air regulator 37 and injected from the air nozzle 31, collides with the fuel injected from the fuel nozzle 12 to help atomize it, and is supplied to the engine through the throttle valve 5.

The metering section 35 is composed of a needle valve and a throttle, and is mechanically or electrically interlocked with the throttle valve 5 to perform fuel control in a low opening range of the throttle valve 5.

In the above embodiment, the injector 11 and the fuel pressure correction mechanism 14 are integrally constructed, but it goes without saying that they may be constructed separately.

[Effects of the Invention] As described above, in the present invention, when adjusting the fuel pressure by amplifying the venturi negative pressure generated in accordance with the amount of intake air with the fuel regulator, the fuel of the fuel regulator is placed in the regulation chamber of the fuel regulator. The fuel pressure adjusted in the adjustment chamber is guided to the pressure adjustment chamber of the fuel pressure correction mechanism located downstream of the metering section, thereby reducing the fuel pressure that increases due to the increase in the amount of intake air. Since the fuel pressure in the adjustment chamber of the fuel regulator and the pressure adjustment chamber of the fuel pressure correction mechanism increases in proportion to the increase in the amount of intake air, the two can be offset. It is possible to always obtain a fuel supply amount that accurately corresponds to the intake air amount.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is a sectional view of a main part, and FIG. 3 is a configuration diagram of a conventional technique. 1... Intake path, 2... Intake path, 3, 4...
...Venturi, 5... Throttle valve, 6...
...Fuel tank, 8...Fuel pump, 10...
...Fuel passage, 11...Injector, 12...
・Fuel nozzle, 13...Fuel regulator, 14...
・Fuel pressure correction mechanism, 15...Return passage, 16...
... Fuel chamber, 17.19.21 ... Diaphragm, 18 ... Negative pressure chamber, 20 ... Atmospheric chamber, 22
...Adjustment room, 23...Control valve, 26...
・Venturi negative pressure path, 28... Pressure regulation chamber, 29.
...Back chamber, 30...Displacement member, 34...
Correction fuel passage, 35... Measuring section,

Claims (1)

[Claims] an intake passage (2) having a bench lily (3); a fuel passage (10) that sends pressurized fuel to a fuel nozzle (12) opened in the intake passage (2); an intermediate part of the fuel passage (10); a negative pressure chamber (18) into which the vent lily negative pressure is introduced, and an atmospheric chamber (2
0), an adjustment chamber (22) into which the adjusted fuel is introduced, and three diaphragms (17, 19, 21) that partition these four chambers (16, 18, 20, 22). a fuel regulator (13) having a control valve (23) and controlling the fuel pressure in response to the vent lily negative pressure according to the opening degree of the control valve (23); the fuel regulator of the fuel passage (10); (13); a pressure regulating chamber (35) formed in a portion of the fuel passage (10) between the metering portion (35) and the fuel injection port (12); 28), a back chamber (29), a displacement member (30) that partitions the two chambers (28, 29), and is driven by this displacement member (30) to adjust the fuel pressure reaching the fuel nozzle (12). a fuel pressure correction mechanism (14) having a valve body (39); branching from the upstream side of the fuel regulator (13) in the fuel passage (10) and passing through the adjustment chamber (22) to the back chamber (29); ), and the fuel pressure correction mechanism (14) maintains a constant pressure drop in the fuel passage (10) downstream of the fuel regulator (13). A fuel supply device for an engine, characterized in that it is configured as follows.