JP2565251Y2 - Oil supply device for two-stroke engine - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil feeding device for a two-stroke engine, and more particularly to an oil collecting device for collecting accumulated oil at the bottom of a crankcase into an intake passage.

[0002]

2. Description of the Related Art In a two-stroke engine, oil is mixed in the intake air, and the essential oil is lubricated by the oil. This oil eventually burns with fuel in the cylinder, but partly accumulates at the bottom of the crankcase.

In Japanese Utility Model Laid-Open Publication No. 2-61108, a connecting pipe is provided for connecting the bottom of a crankcase to a sliding surface of a throttle valve of a carburetor, and a one-way valve is disposed in the middle of the connecting pipe so that the internal pressure of the crankcase is reduced. When the pressure exceeds a predetermined pressure, an engine is shown in which oil accumulated at the bottom of the crankcase is recovered to an intake passage through a carburetor. In this engine, the accumulated oil at the bottom of the crankcase is constantly collected during operation of the engine and is supplied again to the intake passage.

However, the above-described engine has the following disadvantages. That is, at the time of a cold start, etc., although the required temperature of each part of the engine is small due to the low temperature of the engine, a large amount of oil is supplied by an amount re-supplied by collecting the accumulated oil. Becomes more than during normal operation, and white smoke is generated in the exhaust gas.

SUMMARY OF THE INVENTION Accordingly , an object of the present invention is to provide an oil supply device for a two-stroke engine that can easily collect oil accumulated in a crankcase and effectively prevent generation of white smoke at a cold start. is there.

[0006]

[SUMMARY and operation for a] Therefore, in the present invention, the oil feeding device of a two-stroke engine having an oil recovery passage connecting the intake passage crankcase bottom, into the oil collecting passage, predetermined Below temperature
Oil from the bottom of the crankcase to the intake passage
Provide a temperature- sensitive valve that prevents circulation, and
Only when the ignition switch is closed, the ignition
When the switch is open, the crankcase
Not to block oil flow from the bottom to the intake passage.
I do.

According to the present invention, when the temperature is low, the temperature-sensitive valve is closed, and the supply of the retained oil from the bottom of the crank to the intake passage is stopped. Therefore, an appropriate amount of oil not containing the recovered and supplied oil is supplied to the cylinder. As it is introduced and burns well,
No white smoke is generated in the exhaust. When the engine temperature rises and the oil containing the collected oil can be burned without generating white smoke, the temperature sensing valve is opened and the accumulated oil is collected and fed into the intake passage. In addition, the above temperature sensing valve
Above only when the ignition switch is closed
Open / close operation like
The valve operates unnecessarily, causing oil remaining in the crankcase
Without interfering with the emission of waste
To the recovery passage side from the crankcase
Can be pulled out.

[0008]

FIG. 1 is a sectional view showing the structure of an embodiment of the present invention, and FIG. 2 is a sectional view showing the structure of the engine in the embodiment in a section perpendicular to FIG.

In the figure, 1 is a two-stroke engine, 2 is its crankcase, 3 is a cylinder block, and 4 is a cylinder head. A crankshaft 5 is rotatably supported in a crankcase 2 via a main bearing 6, and a crank web 7 is provided.
The large end of the connecting rod 8 is pivotally connected via a crank pin 9. The small end of the connecting rod 8 is pivotally connected to a piston 11 via a piston pin 10, and the piston 11 is connected to a cylinder 12.
The crankshaft 5 is driven to rotate by moving up and down the inside.

The interior of the crankcase 2 communicates with an intake passage 14 through a reed valve 13, and the reed valve 13 opens due to a negative pressure generated in the crankcase 2 during the upward stroke of the piston 11. It is sucked into the crankcase 2 from the passage 14. Reference numeral 15 denotes a vaporizer.
The air-fuel mixture sucked into the crankcase 2 is pre-compressed at the time of the downward stroke of the piston 11, and the scavenging passage 16 and the scavenging port 17
After being sent into the cylinder 12 through the cylinder, the piston 11 is further compressed by the rise of the piston 11 and ignited by the spark plug 18. 19 is an exhaust passage.

The air sucked from the intake pipe 20 is supplied to the carburetor 1
Oil is further injected into the air-fuel mixture generated by adding the fuel in step 5 through an oil supply pipe 21 in the intake passage 14. An oil pump 22 pressurizes the oil, and an oil tank 23 stores the oil. The oil supplied in this manner is dispersed in the air-fuel mixture and is sucked into the crankcase 2, lubricating required parts around the crankshaft 5 and the piston 11, and further conveyed by the air-fuel mixture into the cylinder 12, Here, the fuel is combusted and discharged from the exhaust passage 19, or a part of the oil is separated from the flow of the air-fuel mixture in the form of droplets, and easily accumulates at the bottom of the crankcase 2.

In order to collect the accumulated oil and resupply it to the intake air-fuel mixture, the bottom of the crankcase 2 and the intake passage 1
4 are provided. The oil recovery passage 24 has a conduit 25 communicating with the bottom of the crankcase 2 and extending downward from the crankcase 2, and a conduit 26 communicating with the intake passage 14. A valve 28 is interposed in the pipe 26 so as to allow the collected oil to flow only toward the intake passage 14 side. A temperature sensing valve 33 having a thermostat function is provided in a passage portion 29 connecting the oil recovery chamber 27 and the pipeline 26. That is, the temperature-sensitive valve 33 has a built-in temperature-sensitive part, and operates when the temperature detected by the temperature-sensitive part reaches a set value to open and close. Thus, the passage portion 29 is provided by the leveraged temperature sensing valve 33.
Is opened and closed. The temperature sensing valve 33 is, for example, 60 °
It is set so that the closing operation is performed at C and the opening operation is performed at 80 ° C. The temperature sensing valve 33 is supplied with power by the battery 34, and becomes operable when the ignition switch 35 is closed. As shown, the ignition switch
When the switch 35 is open, the temperature sensing valve 33 is open and
And the passage 29 is not blocked, so that the oil flow is good.
In addition, it can be used as an oil reservoir up to the downstream portion of the temperature sensing valve 33. Obedience
Remove the oil remaining in the crankcase
You can store it here.

When the operation of the engine 1 is stopped, the accumulated oil in the crankcase 2 passes through a pipe 25 to the oil recovery chamber 2.
7 and is stored here, so there is almost no accumulated oil in the crankcase 2. When the ignition switch 35 is turned on and the engine 1 is started from this state, if the operation suspension period is long and the engine 1 is sufficiently cooled, the temperature in the vicinity of the temperature sensing valve 33 is a set value (for example, 60 ° C.). The temperature sensor 33
Closes the conduit 29a. Therefore, the oil 30 in the oil recovery chamber 27 does not flow toward the pipe 26. That is, resupply of oil stored at the bottom of the crankcase to the intake passage 14 by the oil recovery passage 24 is not performed. Therefore, since only a specified amount of oil is supplied to the engine 1 through the oil supply pipe 21, the amount of oil burning in the cylinder 12 is relatively small, and white smoke at the time of starting is reduced.

When the engine temperature rises due to the operation and the temperature near the temperature sensing valve 33 reaches a second set value (for example, 80 ° C.), the temperature sensing valve 33 operates and has been closed until now. The pipe 29a is opened, and the stored oil in the oil recovery chamber 27 flows to the pipe 26, and the intake oil 14 passes through the pipe 26.
Will be resupplied. At this time, since the cylinder temperature has also risen sufficiently, even if a relatively large amount of oil, including resupplied oil, is introduced into the cylinder 12, it burns well and does not produce white smoke.

As described above, according to the present embodiment, it is possible to collect the oil trapped at the bottom of the crankcase and supply the oil to the intake air again, and to effectively prevent the generation of white exhaust gas during a cold start. .

FIG. 3 shows another embodiment of the present invention. In FIG. 3, the same parts as those in FIG. 1 are denoted by the same reference numerals. In this embodiment, the configuration of the passage portion 29 is different from that of the above embodiment. That is, the passage portion 29
A liquid passage 31 for communicating a liquid phase portion below the oil level of the oil 30 stored in the oil recovery chamber 27 with the conduit 26;
A gas passage 32 that connects the gas phase portion above the oil 30 to the pipe 26 is formed. The gas passage 32 is opened and closed by a temperature sensing valve 33. Temperature sensing valve 33
Are set to perform an opening operation at 60 ° C. and a closing operation at 80 ° C., for example.

During a cold start, the temperature in the vicinity of the temperature sensing valve 33 is lower than a set value (for example, 60 ° C.), so that the temperature sensing valve 33 opens the gas passage 32. In this state, even if the oil recovery chamber 27 is pressurized through the crankcase 2 by the piston motion, the gas above the storage oil 30 flows to the pipe 26 through the open gas passage 32 and the liquid Since both ends of the passage 31 are made uniform, the oil recovery chamber 27
The oil 30 does not flow to the pipe 26 side. When the temperature in the vicinity of the temperature sensing valve 33 reaches a second set value (for example, 80 ° C.), the temperature sensing valve 33 operates to close the gas passage 32 that has been opened so far, and to close both ends of the liquid passage 31. Since the pressure equalized state is released, the stored oil in the oil recovery chamber flows through the liquid passage 31 to the pipe 26 side.

The amount of oil that accumulates in the crankcase is
It is mainly governed by the clearance C between the outer peripheral surface of the crank web 7 and the inner peripheral surface of the crankcase 2. When the clearance C is reduced, the amount of accumulated oil is reduced, but high processing accuracy is required, so that the cost increases, and it becomes difficult to collect the accumulated oil due to the influence of viscous resistance. Increasing the gap amount C facilitates the collection of the accumulated oil, but increases the accumulated oil amount, and also lowers the air-fuel mixture pre-compression ratio in the crankcase, lowering the output performance.

Therefore, in the present invention, the gap amount is not changed from a general value to avoid an increase in cost and a decrease in output performance, while keeping the amount of accumulated oil at an appropriate level.
To facilitate the recovery of the oil, FIGS.
As shown, the pipe 2 at the bottom of the crack case 2
5, the accumulated oil recovery port 36 (FIG. 4)
Opposed to the gap formed between the left and right crank webs 7, 7
It is provided in the part which does. Stagnation near the opening
Oil is less likely to rotate with the crank web 7
Oil in the crankcase easily accumulates here
Therefore, the oil in the case is
It can be easily collected in the storage room 27 .

Further, in the embodiment shown in FIGS.
Of the accumulated oil recovery port 36 at the bottom of the crankcase 2
Protrusions 37 are provided on the inner peripheral surface of the crankcase 2 in the vicinity.
You. This convex portion 37 is a crank indicated by an arrow a in FIG.
Under the accumulated oil recovery port 36 with respect to the rotation direction of the web 7
The projection 37 and the crank web
The gap with the outer peripheral surface of 7 is almost eliminated. Inside gap C
Accumulated oil is dragged by the rotation of the crank web 7.
Move along the inner peripheral surface of the crankcase 2 in the direction of arrow a.
Move, and hit the convex portion 37, and the accumulated
Oil is caught by the oil recovery port 36 and recovered through the pipe 25
It falls into the chamber 27. Thus, the collection of accumulated oil is extremely
Performed easily and efficiently. Parts other than the above in this embodiment
Is exactly the same as the previous embodiment, so a detailed description is omitted.
I do.

[0021]

[Effect of the invention] According to the present invention, the oil accumulated at the bottom of the case
A two-stroke engine that collects air and resupplies it to the intake
As a result, accumulated oil can be easily and efficiently collected,
Efficiently prevent the generation of white smoke during cold start
Can be.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a configuration of the engine in the embodiment in a cross section perpendicular to FIG. 1;

FIG. 3 is a sectional view showing a configuration of another embodiment of the present invention.

FIG. 4 is a sectional view showing another embodiment of the present invention.

FIG. 5 is a partial cross-sectional view taken along line VV of FIG. 4;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Crank case, 3 ... Cylinder block, 4 ... Cylinder head, 5 ... Crank shaft, 6 ... Main bearing, 7 ... Crank web, 8 ... Connecting rod, 9 ... Crank pin, 10 ... Piston pin, 11 ... piston, 12 ... cylinder,
13 ... reed valve, 14 ... intake passage, 15 ... carburetor, 16 ... scavenging passage, 17 ... scavenging port, 18 ... spark plug, 19 ... exhaust passage, 20 ... intake pipe, 21 ... oil supply port, 22 ... oil pump , 23 ... oil tank, 24 ... oil recovery passage, 25, 26 ... pipe line, 27 ... oil recovery chamber, 28 ... one valve, 29 ... passage part, 30 ... oil, 31
... liquid passage, 32 ... gas passage, 33 ... temperature sensing valve, 34 ... battery, 35 ... ignition switch, 36 ... accumulated oil recovery port, 37 ... convex part.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A 48-17530 (JP, U) JP-A 46-21130 (JP, Y1) JP-A 52-36906 (JP, Y2)

Claims (1)

(57) [Scope of request for utility model registration] 1. A crankcase bottom and the delivery oil feed of a two-stroke engine having an oil recovery passage connecting the intake passage device, in the oil collection passage, at a predetermined temperature or less
Oil flow from the bottom of the crankcase to the intake passage
A thermo- sensitive valve to block the flow of air
Only activates when the switch is closed and the ignition
When the switch is open, the crankcase
Do not block the oil flow from the bottom to the intake passage
An oil feeder for a two-stroke engine.