JPH025755A - Mechanism for starting fuel injection device - Google Patents

Abstract

PURPOSE:To facilitate the starting of an engine and reduce a cranking time by providing a starter valve for opening/closing a negative pressure passage for applying a manifold negative pressure to a fuel control portion. CONSTITUTION:As a starter motor is rotated from the stopped condition of an engine, a manifold negative pressure is generated. However, since a throttle valve 6 is in the minimum opening position, a starter-valve operating negative pressure introduced from branched operating negative passages 34a, 34b to a starter valve 27 is small, to keep the starter valve 27 in an open condition. Thereby, the manifold negative pressure is introduced from an opening 26 and applied to the negative pressure chambers 10, 10' of fuel control portions 8, 9. Thereby, a quantity of fuel corresponding to each negative pressure is discharged from the fuel control portions 8, 9 into an intake passage 1 via a bypass bleed air passage 21 enabling a thick mixture to be rapidly fed into an engine. Hence, an air-fuel ratio at the time of cranking can be made rich.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a mechanical fuel injection device that controls the amount of fuel injection based on the negative pressure generated in accordance with the air flow rate. In particular, it relates to the starting mechanism.

[Conventional technology]

Conventionally, there is a fuel injection device of this kind, for example, one described in Utility Model Application No. 12254/1983 filed by the applicant of the present invention, and this fuel injection device balances the pressure difference caused by the air flow rate and the fuel pressure difference before and after the orifice. Regarding the pressure balance type fuel control unit that controls the fuel injection amount to maintain a constant air-fuel ratio of the air-fuel mixture, there is a slow type fuel control unit that injects a small amount of fuel according to a small amount of air flow. And a relatively large amount of air 2i! This system is connected to a main system fuel control section that injects a relatively large amount of fuel according to the L scenery, so that control over a wide range can be performed.

When starting the engine, the slow system fuel control unit detects the flow rate of air flowing through the opening of the air pulp at the minimum opening as a differential pressure, injects the appropriate amount of fuel into the intake passage, and supplies the 'a mixture to the cylinder. It is supposed to be done.

[Problem to be solved by the invention]

However, due to the mechanical structure of this type of device or a reaction delay occurring during low-temperature startup, a sufficiently rich mixture is not quickly supplied during cranking, and the air-fuel ratio of the mixture does not become rich. The engine did not always start smoothly, which sometimes resulted in long cranking times.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a starting mechanism for a fuel injection device that can facilitate engine starting and shorten cranking time.

[Means to solve the problem]

A starting mechanism for a fuel injection device according to the present invention is a fuel injection device that includes a pressure-balanced slow system and a main system fuel control section, and includes: a negative pressure passage that applies manifold negative pressure to at least one of the two fuel control sections; The engine is equipped with a starter valve that can open and close this negative pressure passage, and a starter valve operating means that controls the opening and closing of the starter valve, and the starter valve is opened during cranking to supply a rich mixture to the engine. It is something.

[For production]

Therefore, during cranking, in addition to applying negative pressure to the slow system fuel control section due to the normal operation of the fuel injection device,
When the starter valve opens, manifold negative pressure is applied to both fuel control parts or either one, so the fuel discharge amount increases and a rich mixture is supplied to the engine, and when cranking ends, the starter valve is closed. Ru.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on FIGS. 1 and 2.

In the figure, 1 is an intake passage, 2 is an air valve provided on the downstream side of the henchuri section 3, 4 is an actuator that opens and closes the air valve 2 according to the pressure on the downstream side of the air valve 2, and 5 is an actuator that opens and closes the air valve 2 in the slow zone. Idle adjustment screw that maintains the minimum opening 6 is a throttle valve provided downstream of the air valve 2, 7 is an idle adjustment screw that maintains the throttle valve 6 at the minimum opening, 8 is the main system fuel control section, 9 is the slow system In the main system fuel control section 8, which is a fuel control section,
Reference numeral 10 denotes a main system negative pressure passage 11a that receives the negative pressure detected by the main system pressure sensing boat 11 that opens into the henturi section 3.
A negative pressure chamber 12 is introduced through the main system negative pressure passage 11.
13 is a negative pressure diaphragm that partitions the negative pressure chamber 10 and the atmospheric chamber 14; 15 is an upstream chamber into which fuel is sent from the fuel pump P; 16 is a fuel that partitions the upstream chamber 15 and the downstream chamber 17. Diaphragm, 18
is the main jet that communicates the upstream chamber 15 and downstream chamber 17 (
The main system A (orifice) 19 is provided in a passage that bypasses the main jet 18 and is operated by the EC1J (electronic control unit) to adjust the air-fuel ratio of the air-fuel mixture based on each data input to the ECU.
/F solenoid, 20 is a connecting rod connecting both diaphragms 13 and 16, 20a is a valve formed on the connecting rod 20 and can open and close the injection port 17a of the downstream chamber 17, and 21 is connected to the injection port 17a. This is a bypass bleed air passage having an opening 21a to the intake passage 1, ie, a fuel discharge port, on the downstream side of the throttle valve 6. The slow system fuel control section 9 also has the same structure as the main system fuel control section 8, but the negative pressure chamber 10' uses the negative pressure detected by the slow system pressure sensing boat 22, which opens downstream of the air valve 2, as a slow sensing jet. A slow system negative pressure passage 22 equipped with 23
The fuel in the downstream chamber 17 of the main fuel control section 8 is introduced into the upstream chamber 15'. 24 is a fuel pressure regulator.

The above structure is based on the above-mentioned Utility Application filed in 1983-12 as prior art.
It is the same as the fuel injection device in No. 254.

25 is a negative pressure passage having an opening 26 at one end in the intake manifold downstream of the throttle valve 6;
The main system negative pressure passage 11a and the slow system negative pressure passage 22 are branched in the middle and serve as branch negative pressure passages 25a and 25b, respectively.
a on the downstream side of each jet 12 and 23, respectively. Reference numeral 27 denotes a starter valve provided in the middle of the negative pressure passage 25, which is controlled to open and close to introduce manifold negative pressure into the negative pressure chambers 10 and 10' of the main system and slow system fuel control sections 8 and 9; Control the stop. In the starter valve 27, 28 is a diaphragm that partitions the negative pressure chamber 29 and the atmospheric chamber 30, 31 is a valve connected to the diaphragm 28 and can be seated on the valve seat 25C of the negative pressure passage 25, and 32 is the opening direction of the valve 31. The starter valve 27 is a spring that biases the starter valve 27 when the negative pressure in the negative pressure chamber 29 is, for example, 20 mHg.
It is assumed that the valves are configured to close at the front and rear.

32 is the main scooter jet provided in the branch negative pressure passage 25a of the main system, and 33 is the branch negative pressure passage 2 of the slow system.
5b, the values of the negative pressures S, SS in the negative pressure chambers 10, 10' of each fuel control unit 8.9 when introducing manifold negative pressure are determined by the throttle of each passage. That is, in the main system, it is determined by the diameters of the main sensing jet 12 and the main starter jet 32, and in the slow system, it is determined by the diameters of the slow sensing jet 23 and the slow starter jet 33. Reference numeral 34 denotes an operating negative pressure passage whose one end communicates with the negative pressure chamber 29 of the starter valve 27, and which branches in the middle to form a branched operating negative pressure passage 34a34b between the upstream and downstream sides of the throttle valve 6 at the minimum opening position. The other end opens into the intake passage 1, respectively. Reference numerals 35a and 35b are starter valves installed in the branch operation negative pressure passages 34a and 34b, respectively, and during cranking, the negative pressure in the operation negative pressure passage 34, that is, the stark valve operation negative pressure St, is 15 uHg.
Make sure that the negative pressure does not exceed 60℃ after the engine has completely exploded.
〜3 Q is Hg,
The diameter of the starter valve 35b is set, and these constitute starter valve operating means for controlling the opening and closing of the starter valve 27.

This embodiment has the above configuration, and the operation will be explained next. When the starter motor is rotated to start the engine from a stopped state, negative pressure is generated in the manifold, as shown in Figure 2 (
(see A)), negative pressure corresponding to the air flow rate flowing through the opening of the air valve at the minimum opening position (see (B) in the same figure) is detected by the slow system sensing boat 22, and the negative pressure of the slow system fuel control unit 9 is detected. Although the negative pressure is introduced into the pressure chamber 10', the negative pressure is not large enough to supply a rich mixture that facilitates starting the engine.

On the other hand, branch operation negative pressure passages 34a, 3 open upstream and downstream of the throttle valve 6 at the minimum opening position.
Starter valve operating negative pressure S? introduced from 4b to starter valve 27? is 15 mmHg or less ((C) in the same figure)
), the starter valve 27 is maintained in an open state,
Manifold negative pressure is introduced from the opening 26 and applied to each of the negative pressure chambers to and 10' of the main system and slow system fuel control units 8 and 9, and the internal negative pressure SH and Ss of each negative pressure chamber 10 and 10' is As shown in FIGS. 2(D) and (E), the negative pressure is increased from the negative pressure normally applied from each sensing boat 11. Since the fuel is discharged into the intake passage 1 through the bypass bleed air passage 21, a rich air-fuel mixture can be quickly supplied to the engine, and the air-fuel ratio during cranking can be made rich as shown in Fig. 2 (F). This makes it easier to start the engine and reduces cranking time. After the engine completes explosion, the manifold negative pressure further increases (see Fig. 2 (A)), and the branch operation negative pressure passage 34b
The negative pressure introduced from the opening of starter valve 2 also increases.
Starter valve operating negative pressure S applied to the negative pressure chamber 29 of No. 7
, becomes 60 to 80 m1 Hg, so starter valve 2
7 is closed (see figure (C)), the main system fuel control section 8 stops discharging fuel, and the slow system fuel control section 9 also starts discharging fuel in accordance with the negative pressure detected by the slow system pressure sensing boat 22. quantity and return to normal operating condition.

Furthermore, when the throttle valve 6 is depressed, the opening of the branch operation negative pressure passage 34b is also located on the upstream side of the throttle valve 6, but the downstream negative pressure of the air valve 2 is shown by the broken line in FIG. 2(B). Even when the starter valve is fully open and at low speed, the starter valve operating negative pressure S7 does not become lower than the air valve downstream negative pressure (approximately 25 mm Hg) due to the action of the air valve 2, so the starter valve 27 does not open.

As described above, according to this embodiment, since a rich air-fuel mixture can be supplied at the time of starting the engine, the engine can be started easily and the cranking time can be shortened.

FIG. 3 shows a second embodiment of the present invention, in which the negative pressure passage 25 is not branched and is connected only to the slow system negative pressure passage 22a.

Further, No. 412I shows a third embodiment of the present invention, and in this embodiment, the negative pressure passage 25 has a structure in which it is not branched and is connected only to the main system negative pressure passage 11a.

In the second and third embodiments described above, a rich air-fuel mixture can be supplied during cranking as in the first embodiment.

〔Effect of the invention〕

As described above, according to the starting mechanism of the fuel injection device according to the present invention, by applying manifold negative pressure to at least one of the slow system and main system fuel control sections during cranking, the fuel discharge amount is increased and the engine is enriched. The air-fuel mixture can be supplied, making it easier to start the engine and shortening the cranking time.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing a first embodiment of a fuel injection device according to the present invention, and FIGS. 2(A) to (F) are diagrams showing characteristics of the fuel injection device shown in FIG. ) is the manifold negative pressure, (B) is the air valve downstream negative pressure, (C) is the starter valve operating negative pressure 57 (D) is the negative pressure 5s in the negative pressure chamber of the slow system fuel control section (E) is the main system fuel control The negative pressures S and 4 (F) in the negative pressure chamber of 2 are diagrams showing the air-fuel ratio of the air-fuel mixture, respectively, and FIGS. 3 and 4 are sectional views of main parts showing the second and third embodiments of the present invention. be. 6°°゛・Throttle valve, 8... Main system fuel control section, 9... Slow system fuel control section, 11...
Main system pressure sensing boat, 12... Main sensing jet, 22... Slow system pressure sensing port, 23... Slow sensing jet, 2
5... Negative pressure passage, 27... Starter valve, 3
2...Main starter jet, 33...Slow starter jet, 34...Operating negative pressure passage, 34
a, 34b... Branch operation negative pressure passage.

Claims (1)

[Claims] A pressure-balanced slow fuel control unit that discharges a small amount of fuel in response to a small amount of air flow, and a pressure-balanced main control unit that discharges a large amount of fuel in response to a large amount of air flow. A negative pressure passage having one end open to the intake manifold and the other end communicating with at least one of the two fuel control parts to apply manifold negative pressure; a starter valve capable of opening and closing a pressure passage; and a starter valve operating means having openings upstream and downstream of a throttle valve at a minimum opening position and controlling opening and closing of the starter valve according to the negative pressure of the openings. A starting mechanism characterized in that the starter valve is opened during cranking to supply a rich air-fuel mixture to the engine.