JPS59126068A - Fuel injection device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To improve the atomizing characteristic as well as the controlling property of fuel by a method wherein the fuel injection nozzle of the device is constituted of a dual-fluid fuel injection nozzle and the suction port of an air pump, supplying air into the nozzle, is provided in a suction pipe at the downstream side of an air flow amount detecting unit. CONSTITUTION:During the operation of the engine, the fuel, pressurized by a fuel pump 7, is supplied into a metering valve 15 after being regulated in the pressure thereof by a differential pressure regulator 17 so that the differential pressure betwee fore and aft of the metering valve 15 becomes constant. In this case, the delivery side pressure of the metering valve 15 is introduced into the diaphragm chamber of the differential pressure regulator 17 through a pipeline 18. According to this method, the amount of the fuel, sent from the fuel pump 7 to the fuel path 12c of the dual-fluid fuel injection nozzle 12, may be determined by the metering valve 15 and the valve 15 is controlled through a control unit 5 in accordance with the output of an air flow amount sensor 4. The air from the air pump 13 is sent into the air chamber 12a of said nozzle 12 to atomize the fuel.

Description

[Detailed description of the invention] The present invention relates to improvements in fuel injection devices for internal combustion engines.

Conventionally, there has been a device of this type as shown in FIG.

In this conventional device, an air flow sensor 4 is disposed upstream (from a throttle valve 3 of an intake pipe 2 connected to an intake port of an engine l), and a control unit 5 receives a signal from the air flow sensor 4 to control the engine. The system instructs the injectors 6 provided in each of the air manifolds for each cylinder of the engine 1 to inject fuel. Fuel is supplied to each injector 6 by a discharge side piping system 8 of a fuel pump,
A fuel pressure regulator 9 is arranged in parallel with the fuel pump, and its differential pressure sensitive chamber is connected to the intake manifold. is connected to. Note that 10 represents the injected fuel from the injector 6, and 11 represents the exhaust manifold.

According to the conventional fuel injection device having such a configuration,
Pressurized by fuel pump 7 (generally 3.θ atmosphere or more)
The pressure of the fuel is regulated to a fuel injection pressure of 2.5 atmospheres or more by the fuel pressure regulator 9, and then supplied to the injector 6. The injector 6 is a type of electromagnetic valve with good frequency characteristics, and opens in response to a valve opening signal from the control unit 5 to inject fuel. in general,
The fuel injection system is such that the fuel is injected into each cylinder that makes up the engine 1 (multi-point injection method). The above-mentioned valve opening signal to the injector 6 is controlled by the output of the air flow sensor 4 which outputs a signal in accordance with the air flow rate sucked into the engine l. However, the conventional device described above, which aims to achieve an air-fuel ratio of , has the following drawbacks.

(1) Since injection is performed every h cylinders, there are a large number of injectors, which makes them expensive.

(2) Since injection is performed for each cylinder, variations in injector performance are directly reflected in variations in the output of each cylinder.

(3) It requires high-pressure fuel piping and an expensive high-pressure fuel pump.

The present invention was made in order to eliminate the disadvantages of the conventional systems as described above, and by consolidating the fuel injection point to one point, the injection system can be made cheaper, and the output of each cylinder due to variations in the performance of the injection system can be reduced. In addition, by using a two-fluid fuel injection nozzle, good fuel atomization characteristics can be obtained even at low fuel injection pressures, low-pressure fuel piping is required, and the fuel pump is inexpensive and suitable for internal combustion engines. The company aims to provide fuel injection equipment.

An embodiment of the present invention will be described below with reference to FIGS. 2 to 4.

FIG. 2 shows an embodiment of the present invention, in which:
The same reference numerals as in FIG. 1 indicate the same parts or corresponding parts, and detailed explanation thereof will be omitted.

In FIG. 2, 12 is a two-fluid fuel injection nozzle provided in the intake pipe 2, and 13 is an air pump, which sucks air from the downstream side of the air flow sensor 4 and supplies it to the two-fluid fuel injection nozzle 12. Configured to deliver fuel atomization characteristics. 14 is a fuel tank connected to the marine charge pump, 1
5 is a metering valve provided between the fuel pump 7 and the two-fluid fuel injection nozzle 12; 16 is a discharge side piping system of the metering valve 15; 17 is a differential pressure regulator;
A reference pressure is obtained through the discharge pressure detection piping system 18, one end of which is connected to the discharge side piping system 16 of No. A return side piping system 19 connected to 17 is configured to return fuel to the fuel tank i4.

FIG. 3 shows an example of the differential pressure regulator 17, in which P is the pressure on the discharge side of the metering valve 15, P is the pressure on the suction side of the metering valve 15, and 17a is a membrane that seals the fuel. The foot is connected to the needle valve 17b, and the spring 1
The needle valve 17b is opened and closed by the pressure difference between the panel 7e and the pressures p, , p.

As a result, the fuel is returned to the fuel tank 14 without being pushed into the metering valve 15, and the suction side pressure P of the metering valve 15 is increased.

It has the function to adjust.

Further, the two-fluid fuel injection nozzle 12 may be an open type injection nozzle, an example of which is shown in FIG.

In Figure 4, 12& is 0.2k from the air pump 13.
12b is an air injection hole connected to the air flow path 12&, and 12c is a fuel flow path connected to the discharge side piping system 16 of the metering valve 15. A fuel injection hole 12d is connected to the air injection hole 12b near the tip thereof. 12e is injected from the air injection hole 12b and fuel injection hole 12d, and fc
There is a mixing wall between the walls that promotes the mixing of air and fuel.

The operation will be explained based on the above configuration.

The fuel pressurized (about 0.7 atmospheres) by the fuel pump is supplied to the metering valve 15 after its pressure is regulated by the differential pressure regulator 17 so that the differential pressure across the metering valve 15 is constant. However, the two-fluid fuel injection nozzle 12 is an open type nozzle, an example of which is shown in FIG. The internal pressure of the discharge side piping system 16 changes as the fuel flow rate increases or decreases.

Therefore, the internal pressure of the discharge side piping system 16 of the metering valve 15 is collected in the differential pressure regulator 17 by the metering valve discharge pressure detection piping system 18 so that the differential pressure across the metering valve 15 remains constant regardless of the fuel flow rate. , So, in the differential pressure regulator 17, an example of which is shown in FIG. 17b is closed.

Metering valve discharge side pressure P, +pressure P8 due to spring 17c = metering valve suction side pressure P! (1) When the relationship PI + Pg < Pt (2) still holds true, the needle valve 17b-A (opens and the excess fuel sent by the fuel pump is removed). It is forcefully returned to the fuel tank 14 through the 9-side piping system 19, and the suction side pressure of the metering valve 15 is lower.Therefore, the pressure difference between the front and rear of the metering valve 15 is equal to the pressure inside the discharge side piping system 16. The pressure is regulated to a constant pressure by the differential pressure regulator 17, which is used as a reference pressure.As a result, the fuel sent from the fuel pump 7 to the two-fluid fuel injection nozzle 12 is determined by the valve opening degree of the metering valve 15. The fuel is metered according to the output of the control unit 5 corresponding to the output of the control unit 5, and the required amount of fuel can be given to the engine l.At the same time, the air pump 13 is driven to supply air for fuel atomization to the two-fluid fuel injection nozzle 12. to promote mixing of air and fuel.

As described above, according to one embodiment of the present invention, a metering valve whose front and rear pressure difference is kept constant by a differential pressure regulator is disposed between the two-fluid fuel injection nozzle and the fuel pump, and the two-fluid fuel injection nozzle In a configuration equipped with an air pump that sends fuel atomization air to the air intake pipe, a good mixture of fuel and air can be created by pre-mixing the fuel and air between the mixing walls before injecting the fuel into the intake pipe. By adjusting the pressure and flow rate of the air sent from the air pump, the degree of promotion of mixing of air and fuel can be optimally controlled.

In the above embodiment, the differential pressure regulator 17 for adjusting the fuel pressure is arranged on the suction side of the metering valve 15, but as another embodiment of the present invention, as shown in FIG. Even if the fuel flow rate sensor 20 is arranged and the valve opening degree of the metering valve 15 is adjusted according to the fuel flow rate sensor output 20a, there is no change in the operation and effect.

As explained above, according to the present invention, engine operation is achieved by a configuration including a two-fluid fuel injection nozzle that communicates with an air pump that sends air for fuel atomization and a fuel pump that sends fuel through a metering valve. The nitrous fuel ratio can be set to any value depending on the situation, and the opening degree of the metering valve can be easily corrected according to correction factors such as atmospheric temperature, atmospheric pressure, and rate of change in intake desired air flow rate. By concentrating the fuel injection point at one point and adding air for promoting fuel atomization to this injection point, the device can be made inexpensive and the air and fuel can be mixed extremely well. It has the great effect of making it possible. Furthermore, it is obviously a great advantage that the discharge pressure of the fuel pump can be low because the pressure is not applied directly to the injector as in the conventional case.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a conventional fuel injection device for an internal combustion engine, FIG. 2 is a schematic configuration diagram showing an embodiment of the present invention, and FIG.
The figures are a sectional view of the differential pressure regulator shown in Fig. 2, Fig. 4 is a sectional view of the two-fluid fuel injection nozzle shown in Fig. 2, and Fig. 5 is a sectional view of the two-fluid fuel injection nozzle shown in Fig. 2.
The figure is a schematic configuration diagram showing another embodiment of the present invention. l...engine, 2...intake pipe, 3...throttle υ valve, 4...
... Air flow sensor, 5... Control unit,
7...Fuel pump, lO...Injected fuel, 11...
Exhaust-nihold, 12... two-fluid fuel injection nozzle,
13...Air bong! , 14... fuel tank, 15.
... Metering valve, 16... Discharge side piping system, 17... Differential pressure regulator, 18... Metering valve discharge pressure detection piping system, 1
9...Return side piping system, 20...Fuel flow rate sensor. Agent Makoto Kuzuno − @3 Figure P+ Figure 4 Mr. Commissioner of the Japan Patent Office 1. Description of the case Japanese Patent Application No. 58-1361 No. 3, Part 1 to Hitoshi Katayama, representative of the person making the amendment/'Q:' (5゛5, Column for detailed explanation of the invention in the specification to be amended. 6, Amendment Contents (1) r "3.0" on page 3, line 8 of the specification 3.OJ
I am corrected. (2) In the same book, same page, line 10, r 2@5 J is r 2.
5 Correct it as J. (3) Correct "0.2" on page 6, line 11 of the same book to r O, 2J. (4) Correct “0.7” in line 1 of page 7 of the same book to r O, 7J. (5) On the same page, line 16 of the same book, ``When the fuel is sealed and...'' is changed to ``When the fuel is sealed and as a result, the following (
1) When the relationship of the formula holds true,” correct it. (6) Same book, same page, lines 19-20 [Pressure Ps = Metering valve suction side pressure PzJt-r Pressure P8 ≧ Metering valve suction side pressure P
Correct it to 2J. that's all

Claims (3)

[Claims] (1) An air flow rate detection section that outputs a signal proportional to the intake air flow in the intake pipe, a fuel injection nozzle that supplies fuel to the engine, and an air flow rate detection section that injects fuel to the fuel injection nozzle according to the output of the air flow rate detection section. In the fuel injection device for an internal combustion engine, the fuel injection nozzle is configured with a two-fluid fuel injection nozzle, and the suction hole of an air pump that supplies air to the two-fluid fuel injection nozzle is configured as described above. A fuel injection device for an internal combustion engine, characterized in that it is provided in an intake pipe downstream of an air flow rate detection section. (2) For an internal combustion engine according to claim 1, wherein the two-fluid fuel injection nozzle is arranged in a single intake pipe upstream of an intake manifold' branch point in a multi-cylinder internal combustion engine. Fuel injection device. (3) In an internal combustion engine with a supercharger, the two-fluid fuel injection nozzle and the intake hole of the two-fluid fuel injection nozzle for supplying air to the two-fluid fuel injection nozzle are located at the intake manifold P branch point on the downstream side of the supercharger. The internal combustion engine according to claim 1, wherein the internal combustion engine is installed in an intake manifold on the upstream side, or is installed on the downstream side of the air flow rate detection unit and also on the upstream side of the supercharging device. Engine fuel injection system.