JPH0240079A - Fuel injection system for two-cycle engine - Google Patents

Abstract

PURPOSE:To prevent any wastage in fuel from occurring by setting up a fuel injection valve, spraying fuel to the inside of an intake passage at a specified period, at the upstream side of a reed valve in the intake passage in directing its nozzle toward the reel valve. CONSTITUTION:A nozzle 25 of a fuel injection valve 14 adjoins an intake passage 9 at an intermediate position between a throttle valve 12 and a reed valve 13, and it is directed to this reed valve 13. In brief, an axis of the nozzle 25 is tilted to that of the intake passage 9, and most of fuel (f) sprayed out of the nozzle 25 is directly reached to the reed valve 13 without colliding with a wall of the intake passage 9. Since fuel sprayed out of the fuel injection valve 14 is advanced in a crankcase by way of an opening of the reed valve 13, atomized fuel is fed to an engine efficiently and accurately. In addition, such a possibility that fuel stagnate in the intake passage 9 might be spat back to the side of an air intake 11 by a backflow out of the crankcase side just before the reed valve 13 is closed is brought to nothing, thus there is no wastage in fuel at all.

Description

[Detailed description of the invention] Inspired Jakuzuken 1 minute M The present invention relates to a fuel injection device for a two-stroke engine.

In a reed-halve type two-pile engine, the intake port, which is installed in the crank chamber or cylinder and communicates with the intake passage, has a pressure difference between the inside and outside of the crank chamber caused by the piston movement. A thin plate-shaped reed valve is provided that opens when the air is attracted to the air and closes with its own spring force when the pressure difference decreases, and air is sucked into the engine when the reed valve opens. Fuel is supplied into the intake air in the intake passage, and some engines use fuel injection valves to supply this fuel; for example, such an engine is shown in Japanese Patent Laid-Open No. 58-98632. .

In this engine, the amount of intake air is detected based on the amount of variation in crank chamber pressure, and according to this detected value, an injection signal for a predetermined period of time is output to the fuel injection valve from a control device composed of a digital calculator, etc. . When the fuel injection valve receives the injection signal, it opens for the duration and injects an appropriate amount of fuel into the intake passage.

However, in the above-mentioned conventional fuel injection device, the injection port of the fuel injection valve is directed toward the wall of the intake passage, and the injected fuel is first sprayed against this wall. was likely to accumulate, hindering atomization of the fuel and wasting the fuel.

The present invention has been made in view of these circumstances.
In the present invention, a fuel injection valve that injects fuel into the intake passage at a predetermined time is provided on the upstream side of the reed valve of an intake passage communicating with the inside of the engine via the reed valve, and its injection port is connected to the reed valve. Place it towards.

According to the present invention, since the injection port of the fuel injection valve is directed toward the reed valve, if the fuel injection timing is adjusted to the opening timing of the reed valve, the fuel will flow from the fuel injection valve to the opened reed valve. is injected directly into the engine. Therefore, the fuel injected from the fuel injection valve is reliably supplied to the engine in an atomized state, and no fuel is wasted. In addition, the responsiveness of the engine to fuel injection is improved, and, for example, the throttle phenomenon and the breathing phenomenon caused by the delay in fuel supply when opening the valve are effectively prevented.

Figure 1 is a side view of an engine according to an embodiment of the present invention. This engine 1 is a two-cycle V-type two-cylinder engine for a motorcycle. 2 is a head pipe of the motorcycle; 3 is a main frame connected to the head pipe 2; the engine 1 is suspended and supported by the main frame 3;

A crankcase 4 is a crankcase of the engine 1, and two cylinders 5 are juxtaposed and protrude from the front portion thereof in the width direction of the vehicle body. 6 is an exhaust pipe, 7 is a spark plug, and 8 is a cooling water pipe connected to a radiator (not shown).

The inside of the crankcase 4 is divided by a central partition wall into two crank chambers corresponding to the left and right cylinders 5, 5, respectively.Each crank chamber is provided with an intake port 10, and each intake port 10 is provided with an intake port 10. Intake passage 9.
9 is connected and extends upward (see Figure 2). The upper end of the intake passage 9 serves as an air intake port 11 opened between the left and right main frames 3. A throttle valve 12 is provided in the middle of the intake passage 9, and a gate valve 13 is provided at the intake port 10 communicating with the lower end of the intake passage 9.

As shown in FIG. 3, the intake passage 9 is attached to the intake port 10 via a rubber member 28 that is tightened and fixed to the outer peripheral wall of the intake pipe 9a forming the intake passage 9 by means of a band 27. There is. and throttle valve 12 and reed valve 1
Two fuel injection valves 14 are provided for each intake passage 9 at intermediate positions between the two fuel injection valves 3 and 3, and these will be described in more detail later.

The crankcase 4 is also provided with a high-pressure pump 15 that is interlocked with and mechanically driven by the crankshaft, and a fuel tank 16 provided at the top of the main frame 3.
The fuel in the cock is 17. The fuel is sucked into the high-pressure pump 15 through a fuel suction pipe 18. High pressure pump 1
The fuel discharged from 5 is fed into a metal fuel pipe 20 through a fuel discharge pipe 19.

As shown in FIG. 2, the fuel pipe 20 is arranged in a U-shape so as to surround the left and right intake passages 99.
Two connecting pipes 21 made of high-pressure rubber hoses branch from the front and rear parts of the fuel injection valve 0, respectively, and are connected to the corresponding fuel injection valves 14, respectively. The fuel pipe 20 is also provided with a pressure regulating valve 22, and excess fuel is drained into the fuel tank 16 through a return pipe 23 connected to the pressure regulating valve 22.
By returning the oil pressure to 100%, the oil pressure inside the fuel pipe 20 is kept constant.

The fuel injection valve 14 has a built-in electromagnetic opening/closing means 24, and the connecting pipe 2
1 to the fuel injection valve 14 is injected into the intake passage 9 from the fuel injection valve 14 only when the electromagnetic opening/closing means 24 opens. As shown in FIG. 3, the injection port 25 of the fuel injection valve 14 faces the intake passage 9 at an intermediate position between the throttle valve 12 and the reed valve 13, and the injection port 25 faces the reed valve 13. I'm here. That is, the axis of the injection port 25 is greatly inclined with respect to the axis of the intake passage 9,
At least most of the fuel f injected conically from the injection port 25 reaches the reed valve 13 directly without colliding with the wall of the intake passage 9. The reed valve 13 has a normal structure, and as shown in FIG. 4, elastic thin plate-like glue 13b is attached to the upper and lower surfaces of a triangular support frame 13a so that it can be opened and closed. When the pressure in the chamber decreases, the door 13b is drawn toward the crank chamber and opens as shown in FIG. 5, and the air in the intake passage 9 is sucked into the crank chamber through the opening 13c.

An electric signal is input to the electromagnetic opening/closing means 24 through an electric wire 26, and the electromagnetic opening/closing means 24 is opened by this electric signal, but the electric signal is input only when the reed valve 13 is open, and the desired fuel at that time is input. It is controlled by a computer or the like so that it lasts for a period of time corresponding to the amount supplied. Therefore, an amount of fuel corresponding to the desired supply amount is injected from the injection port 25 when the reed valve 13 opens, and this fuel is injected directly toward the opening 13c at the fifth time as shown by the arrow f. . When the engine 1 is rotating at a low speed, only the vertical first injection opening/closing means 24 supplies fuel, and as the rotation increases, the valve opening timing becomes longer. As the rotation speed increases, the second injector installed in the forward direction of the rotation of the crankshaft additionally supplies fuel. At maximum output rotation, both the first and second injectors supply maximum fuel. do.

In this way, in this embodiment, the fuel injected from the fuel injection valve 14 once hits the inner wall of the intake passage 9 as in the conventional case, and then is carried into the crank chamber by the intake air flowing inside the intake passage 9. rather than reed valve 1
3 directly enters the crank chamber through the opening 13c, the injected atomized fuel is efficiently and reliably supplied to the engine, and the fuel stagnant in the intake passage 9 is removed immediately before the reed valve 13 closes. The fuel is not blown back to the air intake port 11 side due to backflow from the crank chamber side, and no fuel is wasted. In addition, the engine has good responsiveness to fuel supply, and the phenomenon of breathing due to fuel delay when the throttle valve 12 is suddenly opened is effectively prevented.

In this embodiment, two fuel injection valves (14, 14) are provided in one intake passage, but in the case of one fuel injection valve, if the axis of the injection port is directed toward the center of the reed valve, good.

As described above, in the present invention, on the upstream side of the reed valve of the intake passage communicating with the inside of the engine via the reed valve,
Since a fuel injection valve that injects fuel into the intake passage at a predetermined time is arranged with its injection port facing the reed valve,
Atomized fuel injected from a fuel injection valve is reliably supplied to the engine, and no fuel is wasted. In addition, the responsiveness of the engine to fuel injection is improved, and the phenomenon of breathing caused by a delay in fuel supply when the throttle is opened or opened is effectively prevented.

[Brief explanation of the drawing]

Fig. 1 is a side view of an engine according to an embodiment of the present invention, Fig. 2 is a schematic top view showing the intake part of the engine, Fig. 3 is a longitudinal sectional view of the intake passage, and Fig. 4 is a reed valve. The perspective view and FIG. 5 are sectional views of the same reed valve. 1... Engine, 2... Head pipe, 3... Main frame, 4... Crank case, 5... Cylinder, 6... Exhaust pipe, 7... Spark plug, 8...・Cooling water pipe, 9...Intake passage, 10...Intake port, 11...
・Air intake port, 12... Throttle valve, 13... Reed valve, 14... Fuel injection valve, 15... High pressure pump, 16... Fuel tank, 17... Cock, 18...
- Fuel intake pipe, 19... Fuel discharge pipe, 20... Fuel pipe, 21... Connection pipe, 22... Pressure regulating valve, 23...
Return pipe, 24... Electromagnetic opening/closing means, 25... Injection port,
26...Electric wire, 27...Band, 28...Rubber part. Agent: Patent attorney Nozomu Ebara and 2 others

Claims (1)

[Claims] A fuel injection valve that injects fuel into the intake passage at a predetermined time is disposed on the upstream side of the reed valve in an intake passage communicating with the engine through the reed valve, with its injection port facing the reed valve. A fuel injection device for a two-stroke engine, which is characterized by: