JP2688830B2 - Separate refueling system for two-stroke internal combustion engine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a separate oil supply system for a two-cycle internal combustion engine.

[Prior Art] According to Japanese Patent Application No. 63-27204, the applicant of the present invention has previously described a two-cycle internal combustion engine having a circulation path in which lubricating oil in an oil tank returns to the oil tank through a membrane oil pump, an oil metering mechanism, and an oil constant pressure mechanism. I have applied for a separate oil supply system for an engine.

However, in this separated oil supply device, (a) the discharge pressure of the lubricating oil decreases as the engine speed increases. (B) When the temperature of the lubricating oil is low, the discharge amount of the lubricating oil is significantly reduced. … There is a problem. This is because the viscosity of the lubricating oil becomes very high at low temperatures, and therefore the operation of the membrane cannot follow the pulsating pressure of the crank chamber in the membrane oil pump.

[Problems to be Solved by the Invention] In view of the above problems, an object of the present invention is to allow a plunger type oil pump to supply lubricating oil in an oil tank to an intake of a carburetor through an oil constant pressure mechanism even if the pulsating pressure of the crank chamber is weak. An object of the present invention is to provide a separate oil supply device for a two-cycle internal combustion engine that can always reliably supply the fuel to the road.

[Means for Solving the Problems] In order to achieve the above object, the configuration of the present invention is such that a predetermined amount of lubricating oil is supplied from an oil tank to a suction passage of a carburetor through a plunger type oil pump and an oil metering mechanism. In a two-cycle internal combustion engine in which the residual lubricating oil is returned from an oil metering mechanism to an oil tank via an oil constant pressure mechanism, the plunger type oil pump has a plunger connected to a membrane defining a pair of working chambers inside the container. While supplying pressurized air from a membrane air pump driven by the pulsating pressure of the crank chamber of the engine to one of the pair of working chambers alternately through a direction switching valve that interlocks with the plunger, The other one of the working chambers is opened to the atmosphere, the plunger has a smaller diameter than the membrane, and the lubricating oil is pressure-fed from the oil tank to the oil metering mechanism.

[Operation] The pulsating pressure in the crank chamber of the engine is supplied to the pair of working chambers partitioned by the membrane of the membrane air pump, and the air pressurized from the pump chambers passes through the switching valve to the working chamber of the plunger type oil pump. Alternately, the plunger is reciprocated. When the plunger moves forward, the lubricating oil in the oil tank is sucked into the cylinder via the check valve, and when the plunger returns, it is sent to the oil metering mechanism via the check valve.

Since the membrane air pump responds to the pulsating pressure in the crank chamber and reciprocates the plunger type oil pump regardless of the engine speed, the lubricating oil is surely passed through the oil metering mechanism to the carburetor of the carburetor even in the high-speed operating range of the engine. It is supplied to the intake passage.

[Embodiment of the Invention] Fig. 1 is a schematic configuration diagram of a separate refueling apparatus for a two-cycle internal combustion engine according to the present invention. The separate refueling device is a carburetor A,
The membrane type air pump E driven by the machine pulsating pressure in the crank chamber 63 of the engine 50, the plunger type oil pump B driven by the membrane type air pump E, and the camshaft 23 which works in conjunction with the throttle valve 41 of the carburetor A. And a constant oil pressure mechanism D for keeping the pressure of the lubricating oil discharged from the plunger type oil pump B substantially constant.

The lubricating oil in the oil tank 43 is sucked into the plunger type oil pump B through the suction passage 20, further sent through the passage 13 to the oil measuring mechanism C, and further sent to the oil constant pressure mechanism D. Oil constant pressure mechanism D
Then, the negative pressure in the intake passage 39 of the carburetor A passes through the passage 36, and the spring force directly acts on the pressure control valve 34. When the pressure in the passage 13 increases, the pressure control valve 34 opens, and the oil in the passage 13 is returned to the oil tank 43 via the pressure control valve 34 and the passage 25.

The oil metering mechanism C includes an oil supply pipe 10 arranged in the middle of the passage 13.
And a needle valve 3 fitted to the oil supply pipe 10 to adjust the passage area of the slit. The needle valve 3 is driven by a cam shaft 23 that is interlocked with a throttle valve 41, enters the oil metering mechanism C from the passage 13, and controls the amount of oil sent to the intake passage 39 of the carburetor A via the passage 38.

FIG. 2 is a side cross-sectional view showing a specific configuration of the above-mentioned separated oil supply apparatus for an internal combustion engine. The membrane type air pump E has one chamber defined by the membrane 46 communicated with the crank chamber 63 of the engine 50, while the other chamber sucks outside air through the check valve 47 as the membrane 46 reciprocates. Pressurized air through check valve 48 and passage 49
It is configured to exhale to. The passage 49 is alternately connected to the passages 52 and 53 by the direction switching valve F.

Plunger type oil pump B is a membrane type actuator G,
The oil metering mechanism C and the oil constant pressure mechanism D are integrally configured. A membrane 54 is provided between the body 45 and the cover 60 of the plunger type oil pump B.
A working chamber 55 is defined on the upper side and a working chamber 56 is defined on the lower side, with the membrane type actuator G configured. Plunger 57 by putting backing plates on both upper and lower sides of membrane 54
Are combined. Plunger 57 includes cover 60 and seal member 61.
Is slidably supported via a spool of the directional control valve F at the outer end. The passage 53 is connected to the working chamber 55.
52 is communicated with the working chamber 56.

The plunger type oil pump B is slidably fitted to a cylinder 59 of the main body 45 with a plunger 57 having a seal member 58 mounted thereon. The cylinder 59 can communicate with the oil tank 43 via the check valve 18 and the passages 19 and 20. In addition, the cylinder 59 has a check valve 14 and a passage.
It is possible to communicate with the constant pressure oil chamber 27 of the oil constant pressure mechanism D via 13.

The oil constant pressure mechanism D is a cover 35 with the film 28 sandwiched under the main body 44.
, The constant pressure oil chamber 27 on the upper side of the membrane 28, and the negative pressure chamber 29 on the lower side.
Are divided respectively. The spring 31 housed in the negative pressure chamber 29 pushes up the pressure control valve 34 connected to the membrane 28, and
It is pressed against the valve seat formed at the end of 26. The passage 26 having the throttle 30 communicates with the oil tank 43 via the passage 25. Spring
The spring force of 31 is adjusted by adjusting bolt 33 screwed to cover 35, and set by lock nut 32. Negative pressure chamber 29
Is communicated with a portion of the intake passage 39 of the carburetor A downstream of the throttle valve 41 via the negative pressure passage 36.

The oil metering mechanism C includes an oil supply pipe 10 and a cam shaft inside the main body 44.
And a needle valve 3 driven by 23. The adjusting bolt 12 is adjustably screwed into the stepped cylindrical portion 2 of the main body 44, and the oil supply pipe 10 is connected to the small diameter cylindrical portion on the tip side. The passage 13 has a throttle 11 disposed in the internal passage of the adjusting bolt 12 and an oil supply pipe 10.
Axial slit 9, passage 37, oil passage 38 provided on the peripheral wall of
Through the intake passage 39 of the carburetor A to the upstream side of the throttle valve 41.

The needle valve 3 for controlling the passage area of the slit 9 is provided with an oil supply pipe 10.
Is slidably fitted to. The needle valve 3 is fixedly supported by a piston 7 fitted into a cylindrical portion 8 provided on the right end side of the main body 14. Due to the force of the spring 6 interposed between the spring seat disposed on the inner end wall of the cylindrical portion 8 and the piston 7, the piston 7 forms a semi-lunar cam 22 of a cam shaft 23 that projects into the cylindrical portion 8. Be abutted. The open end of the cylindrical portion 8 is closed by a lid 24. The lever 21 connected to the camshaft 23 is linked to a throttle lever 40 connected to the valve shaft 42 of the carburetor A by a link (not shown). The needle valve 3 has the seal member 5 fitted inside the cylindrical portion 8. The seal member 5 is held on the inner end wall of the cylindrical portion 8 by the above-mentioned spring seat, and prevents oil leakage from the oil supply pipe 10 to the cylindrical portion 8.

Next, the operation of the separated oil supply apparatus for the internal combustion engine according to the present invention will be described. During operation of the engine, the pulsating pressure in the crank chamber 63 enters the working chamber of the membrane air pump E, and the membrane 46 is oscillated left and right. When the membrane 46 bends to the left, outside air is sucked into the pump chamber on the right through the check valve 47, and when the membrane 46 bends to the right, the air in the pump chamber returns to the check valve 48, the passage 49, and the direction change. It is supplied to the upper working chamber 55 of the membrane actuator G through the valve F and the passage 53.

The pressurized air supplied to the working chamber 55 pushes down the plunger 57 together with the membrane 54. Air in working chamber 56 is in passage 5
2. It is discharged to the outside through the direction switching valve F. When the spool of the directional control valve F moves downward together with the membrane 54, the spool is switched, and the passage 49 communicates with the passage 52 and the passage 53 communicates with the outside. Therefore, the pressurized air from the membrane air pump E is supplied to the working chamber 56 via the check valve 48, the passage 49, the direction switching valve F and the passage 52, and the plunger 57 is pushed up together with the membrane 54. The air in the working chamber 55 is discharged to the outside through the passage 53 and the direction switching valve F. In this way, the plunger 57 is reciprocated up and down.

When the plunger 57 descends, the lubricating oil in the cylinder 59 is sent to the constant pressure oil chamber 27 via the check valve 14 and the passage 13. When the plunger 57 rises, the lubricating oil in the oil tank 43 is sucked into the cylinder 59 via the passages 20 and 19 and the check valve 18.

When the pressure in the constant pressure oil chamber 27 increases, the pressure control valve 34 is pushed down against the force of the spring 31, and the lubricating oil in the constant pressure oil chamber 27 is returned to the oil tank 43 via the throttle 30, the passages 26, 25. Pressure control valve
The valve opening pressure of 34 is the intake passage of the carburetor A that exerts a suction force on the membrane 28.
It is adjusted from the intake negative pressure of 39, but this is only when the engine speed is low.

The lubricating oil in the passage 13 is adjusted by the adjusting bolt 12 in the oil measuring mechanism C.
It is supplied to the intake passage 39 of the carburetor A through the throttle 11, the slit 9 of the oil supply pipe 10, and the passages 37 and 38. This oil amount is controlled by the needle valve 3 which adjusts the passage area of the slit 9.

The stroke of the piston 7 integral with the needle valve 3 is controlled by the rotation of a half-moon cam 22. That is, the opening degree of the throttle valve 41 of the carburetor A becomes large (the engine speed becomes high).
Then, the cam 22 is rotated in the direction opposite to the throttle valve 41 (clockwise direction) in the figure, and the needle valve 3 moves rightward under the force of the spring 6 together with the piston 7. Therefore, the passage area of the slit 9 increases, and the amount of oil supplied from the intake passage 39 of the carburetor A to the engine increases.

The throttle 11 of the oil supply pipe 10 regulates the maximum oil supply required by the engine. The throttle 30 of the oil constant pressure mechanism D raises the pressure of the constant pressure oil chamber 27 in order to prevent the oil supply amount from the oil metering mechanism C from decreasing when the temperature becomes low and the viscosity of the lubricating oil becomes high. This is for increasing the amount of oil supplied from the oil measuring mechanism C, and need not be provided.

The negative pressure chamber 29 of the oil constant pressure mechanism D serves to weaken the force of the spring 31 by introducing the negative intake pressure of the carburetor A during idle operation or low load operation of the engine. Becomes low, and the amount of oil supplied from the oil measuring mechanism C to the engine is reduced during idle operation or low load operation. Therefore, the negative pressure chamber
Even if 29 is set to atmospheric pressure, it works well in normal operation.

In the embodiment shown in FIG. 3, instead of the oil constant pressure mechanism D described above, a passage 13 connected to the discharge port of the plunger type oil pump B is provided.
The throttle 51 is connected to the connection portion with the negative pressure passage 36 connected to the oil tank 43. The throttle 51 suppresses the pulsation of the pressure in the passage 13 and maintains a substantially constant hydraulic pressure.

In the embodiment shown in FIG. 4, instead of the membrane air pump E, a check valve 48a as a one-way valve is provided in the middle of a passage 49 connecting the crank chamber 63 and the direction switching valve F.
In this embodiment, only the positive pulsating pressure of the crank chamber 63 is alternately supplied to the working chamber 55 and the working chamber 56 of the membrane type actuator G.

[Effects of the Invention] As described above, the present invention supplies a predetermined amount of lubricating oil from the oil tank to the intake passage of the carburetor through the plunger type oil pump and the oil measuring mechanism, and the remaining lubricating oil from the oil measuring mechanism to the oil. In a two-cycle internal combustion engine that returns to the oil tank via a constant pressure mechanism, the plunger type oil pump has a plunger inside the container.
The pair of actuations is configured so that pressurized air is supplied from a membrane air pump that is coupled to the membranes defining the pair of working chambers and is driven by the pulsating pressure of the crank chamber of the engine, through a directional switching valve that interlocks with the plunger. At the same time as alternately supplying to one of the chambers, the other of the pair of working chambers is opened to the atmosphere,
The following effects can be obtained.

Even in the high-speed operating range of the engine, the pulsating pressure in the crank chamber drives the membrane air pump, and pressurized air from the membrane air pump is supplied to the membrane actuator via the directional switching valve that automatically operates, driving the plunger type oil pump. Therefore, even if the viscosity of the lubricating oil is high, the lubricating oil in the oil tank is surely supplied to the intake passage of the carburetor via the oil constant pressure mechanism.

A sufficient stroke can be obtained for a plunger type oil pump regardless of the engine speed, so regardless of the viscosity of the lubricating oil,
Lubricating oil in the oil tank is surely supplied to the intake passage of the carburetor through the oil constant pressure mechanism.

Since the crank chamber only communicates with the working chamber of the membrane air pump and the pulsating pressure in the crank chamber is not released to the outside, the engine speed does not fluctuate during idle operation.

When the pulsating pressure of the crank chamber drives the membrane air pump, and the pressurized air from the membrane air pump drives the membrane of the membrane actuator of the plunger oil pump, place the membrane air pump near the crank chamber. The plunger type oil pump can be arranged near the vaporizer or the oil tank.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a separation oil supply apparatus for a two-cycle internal combustion engine according to the present invention, FIG. 2 is a side sectional view of the separation oil supply apparatus, and FIG. 3 is a separation oil supply according to a partially modified embodiment of the present invention. FIG. 4 is a schematic configuration diagram of the device, and FIG. 4 is a configuration diagram showing a main part of a separation oil supply device according to a second embodiment of the present invention. A: Vaporizer, B: Plunger type oil pump, C: Oil metering mechanism, D:
Oil constant pressure mechanism, E: Membrane air pump, F: Direction switching valve, 3: Needle valve, 10: Oil supply pipe, 12: Adjustment bolt, 23: Cam shaft, 28: Membrane,
34: pressure control valve, 39: intake passage, 40: throttle lever, 41:
Throttle valve, 43: Oil tank, 48a: One-way valve, 54: Membrane, 57: Plunger

Claims (2)

(57) [Claims] 1. A predetermined amount of lubricating oil is supplied to an intake passage of a carburetor from an oil tank through a plunger type oil pump and an oil measuring mechanism,
In a two-cycle internal combustion engine in which the residual lubricating oil is returned from an oil metering mechanism to an oil tank via an oil constant pressure mechanism, the plunger type oil pump has a plunger connected to a membrane defining a pair of working chambers inside the container. While supplying pressurized air from a membrane air pump driven by the pulsating pressure of the crank chamber of the engine to one of the pair of working chambers alternately through a direction switching valve that interlocks with the plunger, Of the two-cycle internal combustion engine, characterized in that the other of the working chambers is opened to the atmosphere, the plunger has a smaller diameter than the membrane, and the lubricating oil is pumped from the oil tank to the oil metering mechanism. Separator machine oil supply device. 2. A predetermined amount of lubricating oil is supplied to an intake passage of a carburetor from an oil tank through a plunger type oil pump and an oil measuring mechanism,
In a two-cycle internal combustion engine in which the residual lubricating oil is returned from an oil metering mechanism to an oil tank via an oil constant pressure mechanism, the plunger type oil pump has a plunger connected to a membrane defining a pair of working chambers inside the container. , Alternately supplying pressurized air from the crank chamber of the engine to one of the pair of working chambers via the one-way valve and the directional switching valve interlocking with the plunger while simultaneously supplying the other of the pair of working chambers. A separator refueling device for a two-cycle internal combustion engine, wherein the plunger has a diameter smaller than that of the membrane, and the lubricating oil is pressure-fed from the oil tank to an oil metering mechanism.