JPH04136478A - Air/fuel injection valve device for engine - Google Patents

Abstract

PURPOSE:To greatly broaden the control range for the fuel injection quantity by installing a subfuel feeding system for continuously feeding fuel to the upstream side of a main valve and an electromagnetic opening/closing valve for operating the subfuel feeding system in the prescribed operation region of the engine. CONSTITUTION:An air/fuel injection valve 28 is equipped with at least an electromagnetic type fuel injection valve 32. Further, the air used in the injection valve 28 is introduced into an air passage 72 by an air pump 70. Further, gasoline fuel is introduced into the fuel passage 76 of the fuel injection valve 32 from a fuel tank 80 by a fuel pump 78. In this case, the discharge side of the fuel pump 78 and the fuel injection valve 32 are allowed to communicate through a fuel pipe 90 which forms a subfuel feeding system, and an electromagnetic opening/closing valve 92 is interposed midway in the pipe 90. The electromagnetic opening/closing valve 92 is opened by a controller 94 under the prescribed operation condition such as in high loading on the basis of the data which shows the operation state, and fuel is added from the subfuel feeding system 90.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an air/fuel injection valve device for pre-mixing liquid or gaseous fuel and air and injecting the mixture into a combustion chamber of an engine.

(Background of the Invention) In recent years, in order to prevent the air-fuel mixture from blowing through in two-cycle engines, research has been conducted on in-cylinder injection methods in which fuel is directly injected into the combustion chamber. In order to atomize the fuel, an air/fuel injection method has been proposed in which air and fuel are mixed in advance and injected into the cylinder. In conventional fuel injection valves, if the injection port is set to a small diameter to control a small amount of injection, the injection amount cannot be increased sufficiently. When the diameter is made large, there is a problem that it becomes impossible to control the small injection amount with high precision. For this reason, there was a problem that the control range of the fuel injection amount became narrow.

(Object of the Invention) The present invention has been made in view of the above circumstances, and an object thereof is to provide an air/fuel injection valve device for an engine that can significantly expand the control range of the fuel injection amount. It is something.

(Structure of the Invention) According to the present invention, the object is to inject a mixed flow of fuel intermittently injected from a fuel injection valve and air at a predetermined pressure into a combustion chamber intermittently by opening and closing a main valve. - The fuel injection valve device is characterized by comprising a sub-fuel supply system that continuously supplies fuel to the upstream side of the main valve, and an electromagnetic on-off valve that operates the sub-fuel supply system in a predetermined operating range of the engine. This is achieved by the engine's air/fuel injection valve system.

(Operation) In a predetermined operating range such as when the engine is operating under high load, the electromagnetic on-off valve opens and the auxiliary fuel supply system becomes operational. In this state, the auxiliary fuel supply system continuously supplies fuel to the upstream side of the main valve. Therefore, in this operating range, fuel is supplied from both the fuel injection valve and this auxiliary fuel supply system. Further, during low/medium load operation outside the predetermined operation range, for example, the if electromagnetic on-off valve closes and the auxiliary fuel supply system becomes inoperable.

Therefore, fuel is supplied only from the fuel injection valve.

(Example) Fig. 1 is an overall view of one embodiment of the present invention, Fig. 2 is an injection characteristic diagram thereof, Fig. 3 is an overall view of another embodiment, Fig. 4 is an injection characteristic diagram thereof, and Fig. 5 is an overview diagram of an embodiment of the present invention. The figure is a cross-sectional view of the air/fuel injection valve, and FIGS. 6 and 7 are cross-sectional views showing different embodiments near the main valve.

In Fig. 1.3, numeral 10 is a two-stroke engine;
12 is a crankshaft, 14 is a piston, and 16 is a cylinder. Intake air flow meter 18, throttle valve 20
, is sucked into the crank chamber 24 via the reed valve 22.

An air/fuel injection valve 28 described in FIG. 5 is attached to the top of the combustion chamber 26, from which a mixed flow of fuel and air is intermittently injected into the combustion chamber 26 at predetermined timings.

30 is a spark plug.

The air/fuel injection valve 28 includes a known electromagnetic fuel injection valve 32 shown in FIG. 5, and an electromagnetic solenoid 34 for cutting off and on the outflow of the mixed flow.

That is, the movable piece 36 of the electromagnetic solenoid 34 is restricted from moving in the lateral direction by a diaphragm 40 inside the case 38, and is given the tendency to return upward by a return spring 42. The upper end of the valve shaft 44 is fixed to the movable piece 36.

An inner tube 46 and an outer tube 48 are fixed to the lower surface of the case 38. The inner cylinder 46 is coaxially inserted into the outer cylinder 48, forming a fuel passage 50 between the two cylinders 46,48. The valve shaft 44 descends through the inner cylinder 46, and the umbrella-shaped valve body 52 provided at the lower end of the valve shaft 44 contacts the valve seat 54 of the inner cylinder 46 from below to open the main valve 56. form (Figure 6.7).

In the embodiment shown in FIG. 6, a disk 58 is formed on the valve shaft 44 at a predetermined interval above the valve body 52, and in the embodiment shown in FIG. There is. Four radial claws 60 are formed above the disk 58 and the cylinder 58A. The disk 58 and the cylinder 58A form an annular diaphragm 62.62A (see FIG. 6.7) with a constant interval between the disk 58 and the inner wall of the inner cylinder 46.

The four claws 60 slide on the inner wall of the inner cylinder 46 to restrict movement of the valve shaft 44 in the radial direction. A mixing chamber 64 is formed between the claw 60 and the disk 58 or cylinder 58A. The aforementioned throttle 62.62A opens and closes the mixing chamber 6 as the main valve 56 opens and closes.
It has the function of suppressing pressure changes of 4.64 A and stabilizing the fuel injection amount. The lower end of the fuel passage 50 communicates with this mixing chamber 64.64A by an orifice 66.

The air used in this injection valve 28 is pressurized by an air pump 70 shown in FIG. 1.3, and the air passage 70 shown in FIG.
2 to the mixing chamber 64.64A (No. 6.7) between the inner cylinder 46 and the valve shaft 44.
Figure). In Fig. 1.3, 76 is a relief valve that keeps the air pressure constant (for example, 5.0 kg/cm2).

The fuel injection valve 32 is attached to the case 38, and fuel is supplied to the fuel passage 76 at a pressure slightly higher than the air pressure (for example, 5.5 kg/cm2).

That is, the fuel pump 78 shown in FIG. 1.3 sucks up gasoline fuel from the fuel tank 80, pressurizes it, and then discharges it. A relief valve 82 is connected to the discharge side of the fuel pump 78, so that the discharge pressure is constant (for example, 5.5 kg). /cm2).

This constant pressure fuel flows into the fuel passage 7 of the fuel injection valve 32.
6. Gasoline fuel injected from the fuel injection valve 32 is formed in the case 38 and the outer cylinder 48 and flows through the fuel passage 8.
4 (FIG. 5) and is led to the fuel passage 50 between the inner and outer cylinders 46 and 48. This fuel is further fed to the orifice 66.
and flows into the mixing chamber 64.64A.

In FIG. 1, reference numeral 90 is a fuel vibrator forming an auxiliary fuel supply system, and this vibrator 90 communicates the discharge side of the fuel pump 78 with the fuel passage 84.

An electromagnetic on-off valve 92 is interposed in the middle of this vibrator 90, which closes the vibrator 90 when it is not energized and opens it when it is energized.

Further, in the embodiment shown in FIG. 3, another relief valve 82A is connected downstream of the relief valve 82. This relief valve 82A opens at a pressure lower than that of the relief valve 82 and approximately equal to air pressure (for example, 5.0 Kg/cm2) to return the fuel to the tank 80.

In this embodiment, a fuel vibrator 90 serves as an auxiliary fuel supply system.
A is the electromagnetic on-off valve 92 from between both relief valves 82 and 82A.
The fuel is introduced into the fuel passage 84 through the fuel passageway 84 .

In FIG. 1.3, 94 is a control device consisting of a CPU, memory, etc., and controls the electromagnetic on-off valve 92, the fuel injection valve 32, the electromagnetic solenoid 34, etc. That is, when data indicating the operating state such as the intake flow rate Q detected from the air flow meter 18, the opening degree θ of the throttle valve 20, and the rotational speed N of the crankshaft 12 is input to this control device 94, this control device 92 The fuel injection amount suitable for the operating conditions is read from the memory, and the opening time τ of the electromagnetic solenoid 34 and the fuel injection valve 32 is determined.

Also, under certain operating conditions such as during high loads, the solenoid on-off valve 92
Open it and add fuel from the auxiliary fuel supply system.

Next, the operation of the embodiment shown in FIG. 1 will be explained. The control device 92 closes the electromagnetic on-off valve 92 under predetermined conditions such as during low/medium load, opens the combustion injection valve 32 during the period when the main valve 56 is open, and supplies fuel only from the fuel injection valve 32. . At this time, as shown by a in FIG. 2, the injection amount q increases approximately in proportion to the valve opening time. When a predetermined condition such as high load is reached, the electromagnetic on-off valve 92 opens (then fuel is supplied to the fuel passage 84 via the vibrator 9o, which is an auxiliary fuel supply system. This fuel pressure (approx. ) is the air pressure (approximately 5
, 0 Kg/Cm"), so fuel is continuously supplied, but when the main valve 56 is opened, the pressure in the mixing chamber 64 decreases and the pressure between the fuel supply side and the discharge side of the fuel injection valve 32 decreases. As the differential pressure increases, the supply amount increases.

Therefore, the amount of fuel q supplied from the auxiliary fuel supply system increases slightly as the valve opening time increases, as shown by b in FIG. As a result, the total fuel amount C at this time becomes c=:a+b as shown by the solid line.

Further, according to the embodiment shown in FIG. 3, the operation at low and medium loads when the N-magnetic on-off valve 92 is closed is the same as that shown in FIG. However, when the electromagnetic on-off valve 92 is opened under high load, the fuel pressure determined by the relief valve 82A is approximately equal to the air pressure, which is different from that shown in FIG. 1. That is, even if the electromagnetic on-off valve 92 is open, fuel is not supplied from the vibrator 9OA when the main valve 56 is closed, and fuel is supplied only when the main valve 56 is opened and the pressure in the mixing chamber 64A is reduced. Therefore, the amount q supplied from the auxiliary fuel supply system at this time is approximately proportional to the opening time of the main valve 56, as shown by b' in FIG. As a result, the total supply amount C' becomes c' = a + b'.

In the above embodiments, the fuel injection valve 32 is opened during the opening period of the main valve 56 and the fuel injection valve 32 is opened. It may be something that does not exist.

Further, in this embodiment, the auxiliary fuel supply system supplies fuel to the fuel passage 84, but in the present invention, as long as it is upstream of the main valve 56, it supplies fuel to the mixing chamber 64.64A and the air passage upstream thereof. There may be.

(Effects of the Invention) As described above, the present invention allows the electromagnetic on-off valve to open the auxiliary fuel supply system in a predetermined operating range such as during high load. Fuel is also supplied from the auxiliary fuel supply system.

Furthermore, under low or medium load conditions, the electromagnetic on-off valve closes the auxiliary fuel supply system, so fuel is supplied only from the fuel injection valve.

As a result, the control range of fuel supply amount has been expanded by 4°. make it big

[Brief explanation of drawings]

Fig. 1 is an overall view of one embodiment of the present invention, Fig. 2 is an injection characteristic diagram thereof, Fig. 3 is an overall view of another embodiment, Fig. 4 is an injection characteristic diagram thereof, and Fig. 5 is an air 6 and 7 are sectional views showing different embodiments of the fuel injection valve in the vicinity of its main valve. 28... Air/fuel injection valve, 32... Fuel injection valve, 34... Electromagnetic solenoid, 56... Main valve, 70... Air pump, 78... Fuel pump, 90.90A. ...Fuel pipe serving as the auxiliary fuel supply system, 92...1ffn on-off valve. Patent applicant Yamaha Motor Co., Ltd.

Claims (1)

[Scope of Claims] An air/fuel injection valve device that intermittently injects a mixed flow of fuel intermittently injected from a fuel injection valve and air at a predetermined pressure into a combustion chamber by opening and closing a main valve, comprising: An air/fuel injection system for an engine characterized by comprising a sub-fuel supply system that continuously supplies fuel upstream of the main valve, and an electromagnetic on-off valve that operates the sub-fuel supply system in a predetermined operating range of the engine. Valve device.