JPS631755A - Fuel injection device for engine - Google Patents

Abstract

PURPOSE:To improve the startability with this simple structure, in the titled device where air and fuel which are intaked into a plunger chamber by the reciprocating motion of a plunger are mixed and atomized so as to be injected into a combustion chamber, by providing a variable throttle valve for adjusting the intaked air quantity. CONSTITUTION:A cylinder 7 to which a pair of pistons are inserted as facing each other is formed in an intermediate case of a rotatable cylinder case 3 and an intake/exhaust port 15 is formed as facing to the combustion chamber between both pistons. On the sliding surface of a head portion 14 formed at the center of a rear case 1b of a body case 1, an intake/exhaust hole and injection hole 18 are formed in the moving direction of the intake/exhaust port 15. Inside the head portion 14, a pump casing 29 is buried and air in intaked by the reciprocating motion of the plunger 32 through a passage 38 in which a variable throttle valve 39 is interposed. The fuel is intaked through a fuel control valve 37 in which the opening thereof is controlled by a governor including a governor weight 44 and injected to the combustion chamber through the injection hole 18.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is configured so that air is sucked into the plunger chamber during the return stroke of a plunger driven in synchronization with the rotation of an engine, and the air is sucked into the plunger chamber. A fuel inlet is connected to the intake passage through a fuel control valve whose opening is adjusted by a governor device, so that fuel is atomized and mixed into the intake air as air is drawn into the plunger chamber. The present invention relates to a fuel injection device for an engine configured to inject air-fuel mixture compressed by the advancing operation of a plunger into compressed intake air in a cylinder through a fuel injection hole.

[Conventional technology]

In recent years, the most common fuel injection method for compression ignition engines is the airless injection method, in which only fuel is highly compressed and injected into the cylinder.
ype) has been adopted. This method requires high-pressure injection to improve atomization and combustion during fuel injection, and various injection pumps and injection nozzles are used. It is common practice for an injection pump to be equipped with a fuel discharge amount adjusting means for controlling the speed of the engine, and to be controlled by a governor device.

However, since the injection pump performs high compression of the fuel and adjusts the fuel discharge amount, the structure of the injection pump becomes extremely complicated. Therefore, as mentioned above, the fuel is atomized in the plunger chamber and this atomized fuel is injected into the cylinder, so that even an injection pump with a relatively low compression force and simple structure can normally compress and ignite the fuel. Research on injection devices is beginning.

[Problem that the invention seeks to solve]

In compression ignition engines, a starting fuel increasing means is incorporated into a governor device linked to a fuel injection device in order to improve startability, and the governor device is therefore complicated.

Focusing on this point, the present invention utilizes a fuel injection device that does not directly inject liquid fuel as described above, but rather uses a fuel injection device that atomizes liquid fuel in the plunger chamber and then injects it into the cylinder. It is an object of the present invention to provide a mechanism for improving the startability of a compression ignition engine with a simple structure.

[Means for solving problems]

A feature of the present invention is that in the fuel injection device for an engine described above, a variable throttle valve for adjusting the amount of inflow air is provided at a location above the fuel control valve in the air intake passage, and its operation and effects. is as follows.

[For production]

When a variable throttle valve as mentioned above is installed, if the variable throttle valve is throttled during engine starting operation, the inflow of air into the plunger chamber will be extremely restricted, and a large amount of air will be forcibly released by the negative pressure during the return stroke of the plunger. Fuel is drawn into the plunger chamber. This results in a very rich mixture of fuel in the plunger chamber.

〔Effect of the invention〕

As described above, it is now possible to form a very rich mixture of fuel in the plunger chamber when starting the engine without providing any special mechanism to the governor device, and this mixture can be injected into the cylinder. As a result, the startability of compression ignition engines employing the above-mentioned fuel injection system has improved. Furthermore, if the passage area of the variable throttle valve is set sufficiently large when the valve is fully open, the air-fuel mixture formed in the plunger chamber when the valve is fully open will be very thin of fuel, making it impossible to sustain combustion.
This variable throttle valve can also be used as an engine stopping means.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on illustrative drawings.

FIGS. 2 and 3 show the entire longitudinal side view of the engine, and FIG. 4 shows its longitudinal front view. The main body case (1) of this engine is constructed in two halves, with a front case (1a) on the output side and a rear case (1b) on the head side bolted together.
), a cylinder case (3) is rotatably supported horizontally via bearings (2), (2).

The cylinder case (3) has the bearing (2)
, Front and rear sleeve cases (4) supported by (2),
(5) and an intermediate case (6) sandwiched and connected between them.
A penetrating cylinder (7) having an axis perpendicular to the rotating wheel center (Pl) of the cylinder case (3) is formed in the intermediate case (6).

The cylinder (7) has a pair of pistons (8), (8)
The rollers (9) are rotatably supported on the skirt portion of each piston (8) via a piston pin (10).

The front and rear cases (la) and (l) of the main body case (1)
A cam plate (12) is fastened together between b),
This cam plate (12) has an oval inner peripheral surface (1
3) into the cam hole (13), both the pistons (8),
The rollers (9) and (9) of (8) are configured to be inscribed, and each piston (8) reciprocates twice for each rotation of the cylinder case (3).

An engagement guide portion (
A guide rail (13a) is provided, and a guide portion (11) is connected to the guide rail (13a) in a portion extending from the skirt portion of both pistons (8), (8).
13a) so that the piston (8
) is configured so that the roller (9) does not separate from the inner peripheral surface of the cam hole (13).

The rear end surface of the cylinder (7) is configured to slide in the axial direction of the cylinder case (3) with a head portion (14) formed at the center of the rear case (1b), and the cylinder case (3) is attached to the rear end surface of the cylinder. ) is formed with one intake/exhaust port (15) eccentric to the rotation axis (P, ). Furthermore, exhaust holes (16) are formed on the sliding surface of the head portion (14) at a predetermined angular phase along the moving direction of the intake and exhaust ports (15).
), an intake hole (17), and a fuel injection hole (18), and as the cylinder case (3) rotates, the intake and exhaust ports (
15) are located in the exhaust hole (16), intake hole (17) and injection hole (18) in sequence at appropriate timings to perform four cycles of exhaust, intake, compression, and explosion expansion, thereby removing the cylinder case (3). is continuously rotated in the - constant direction (A).

The rotational output of this cylinder case (3) is then applied to a pulley (19) attached to the outer end of the front cylinder shaft case (4).
, or P inserted into the shaft end spline hole (20)
It is adapted to be taken out from a TO shaft (not shown).

In addition, the output pulley (
A fan (21) is attached together with the cylinder (19), and the outside air taken in from the opening (22) formed at the rear center of the rear cylinder shaft case (5) is passed through the rib (23) around the cylinder (7).
After the cooling air passes through the cooling air passage (24) formed between the parts, it is sucked and discharged from the exhaust port (25) provided on the front end circumference of the front cylinder shaft case (4), and is discharged from the head part (14) and the cylinder. (
7).

As shown in FIG. 5, a muffler (26) communicating with the exhaust hole (16) is provided on the outer side of the head portion (14).
Air cleaners (27) communicating with the intake holes (17) are connected to each other, and a fuel inlet (28) is provided which is connected to a fuel tank (not shown) through piping.
is connected to a fuel injection device described below.

Details of the fuel injection system are shown in FIG.

That is, a plunger type pump casing (29) is embedded and fixed inside the head portion (14), and the fuel injection hole (18) is formed at the tip thereof.

A plunger (32) that is directly driven forward and backward by the rotational force of the cylinder case (7) is fitted into the pump casing (29). The plunger (
32) in detail, there is a governor case (30) which is a rotating shaft (30) at the position of the rotating shaft center (P, ) of the cylinder case (3) and into which a governor mechanism, which will be described later, is fitted.
is attached and inserted into the head part (14) so that the governor case (30) also rotates within the head part (14) as the cylinder case (3) rotates.

Then, a cylindrical cam (31) having a cam tfi (31a) having a semicircular cross section on its outer peripheral surface is attached to the governor case (30) with a spline structure, and this cylindrical cam (31) is attached to the plunger (32). The cylindrical cam (31
) by interposing a steel ball (54) between the cam groove (31a) and the plunger (32) to form a cam mechanism, the plunger (32) is It is configured to be driven back and forth once.

More specifically, the plunger chamber (33) formed in the pump casing (29) has a plunger (
A group of small holes (34) are formed that are opened when the 32) is retracted, and this group of small holes (34) connects the annular groove (35), the passage (36) provided in the governor case (30), and the air It is connected to a passage (38) branching from the cleaner (27) and having a variable throttle valve (39).

Additionally, an air intake passage (41) is provided which directly communicates the plunger chamber (33) and the air cleaner (27) without communicating with the governor case (30). A valve (42) is provided. Note that the on-off valve (42) is closed during normal operation.

The rotation axis (p) is located inside the governor case (30).
A cylindrical fuel control '4'Ill valve (
37) is installed internally, and this fuel amount'<111 valve (3
7) is slidably operated by a governor rod (45) via a governor spring (43). Fuel is supplied to the head (14
) The passageway (3
6) Go inside. The fuel amount is controlled by the fuel control valve (37) as described above by the speed control arm (46) connected via the speed control lever (not shown) and the release wire (47).
The speed is set by sliding the fuel control valve (37) and adjusting the opening of the annular groove (37b) communicating with the small hole (37a) of the fuel control valve (37) and the passageway (36).

The fuel control valve (37) is configured to be controlled to advance or retreat by a mechanical governor, and the governor includes a governor spring (43) that presses the fuel control valve (37) in a direction to increase the opening degree; Governor weight (44
).

The governor weight (44) is attached to the cylinder case (3).
It is housed in a recess (48) formed eccentrically with respect to the rotation axis (Pl) at the rear end, and is pivotably supported on a bracket (49) fixed to the cylinder case (3). There is. Then, the arm (44a) connected from the governor weight (44) comes into contact with the tip of the push rod (37c) connected from the fuel control valve (37), and the centrifugal force of the governor weight (44) ( governor force) is transmitted to the fuel control valve (37).

The entire engine is constructed as described above, and its operation will be described in detail next.

The cylinder case (3) is rotated clockwise in FIG.
6) and both pistons (8).

After (8) moves closer and exhausts air, the intake and exhaust ports (
15) overlaps with the intake hole (17) while both pistons (8)
, (8) move away from each other due to centrifugal force, air is taken into the cylinder (7), and the intake air continues to enter the compression stroke.

By the end of this intake compression stroke, the plunger (32)
is driven backward and forward once, and as the plunger (32) retreats, air is rapidly sucked into the plunger chamber (33), and at this time, the negative pressure generated in the passage (36) causes fuel to be discharged from the fuel control valve (37). is sucked in and atomized into the air.

When the engine is started, if the variable throttle valve (39) in the passage (38) is throttled, a large amount of fuel is sucked in by the negative pressure, so that a very fuel-rich mixture is formed. The air-fuel mixture formed in this way flows through the small holes (34
) into the plunger chamber (33), and atomization of the fuel is further promoted at this time. And the plunger (3
Due to the forced advance in step 2), a certain amount of the air-fuel mixture in the plunger chamber (33) is compressed and becomes a high-pressure, high-temperature air-fuel mixture.

After this air-fuel mixture compression is completed, the intake/exhaust port (15) of the cylinder case (3), which has completed the intake compression stroke, becomes the injection hole (18).
The high-pressure, high-temperature air-fuel mixture in the plunger chamber (33) is ejected into the high-temperature compressed air in the cylinder (7), and the explosion and expansion stroke begins. During this explosion expansion stroke, the plunger (32) is held at the final advance (compression) position, and the flow of combustion gas into the plunger chamber (33) is prevented.

Then, the explosion and expansion stroke is followed by the exhaust stroke,
This cycle is then repeated.

The intake/exhaust port (15) and the head portion (14) when the cylinder (7) is in the intake compression stroke and explosion expansion stroke.
In order to improve the airtightness at the sliding contact area, a thrust ring (51) with a seal ring (50) is fitted into the stepped part of the mouth edge of the intake/exhaust port (15) to reduce the internal pressure of the cylinder (7) by thrusting. The thrust ring (51) is configured to be brought into close contact with the head portion (14) by acting on the front gap (52) of the ring (51). Further, an annular groove (53) is formed on the end face of the head portion (14) to collect gas leaked from the intake/exhaust port (15), and the negative part of the annular groove (53) is a passage. (not shown) to the intake hole (17), so that the gas collected in the annular m (53) is returned to the cylinder (7) together with the intake air.

When the on-off valve (42) of the air intake passage (41) is opened when the engine is stopped, a large amount of air flows into the plunger chamber (33), and an extremely large amount of fuel that cannot be ignited enters the plunger chamber (33). This creates a lean air-fuel mixture, allowing the engine to stop suddenly.

C-Different Embodiment] The fuel injection device according to the present invention can be used not only for the above-mentioned rotating cylinder case type engine, but also as a fuel injection device for a general diesel engine with intake and exhaust valves.

[Brief explanation of the drawing]

The drawings show an embodiment of the fuel injection device for an engine according to the present invention, and FIG. 1 is a sectional view of the vicinity of the head of the engine, and FIG.
3 and 3 are cross-sectional views showing different rotational phases of the cylinders, FIG. 4 is a cross-sectional front view of the engine, and FIG. 5 is a front view of the engine. (7)...Cylinder, (18)...Fuel injection hole, (28)...Fuel inlet, (32)
...Plunger, (33) ...Plunger chamber, (36) ...Passway, (37) ...
...Fuel control valve, (39)...Variable throttle valve.

Claims (1)

[Claims] A plunger (32
) is configured to suck air into the plunger chamber (33) during the return stroke of the plunger chamber (33), and a fuel control valve (37) whose opening degree is adjusted by a governor device is provided in the air intake passage (36) to the plunger chamber (33). ) through the fuel inlet (2
8) are connected in communication so that fuel is atomized and mixed into the intake air as air is drawn into the plunger chamber (33), and the air-fuel mixture compressed by the advancing operation of the plunger (32) is injected. A fuel injection device for an engine configured to inject compressed intake air in a cylinder (7) through a hole (18), the fuel injection device comprising:
) is equipped with a variable throttle valve (39) for adjusting the amount of incoming air on the upper side of the fuel control valve (37).