JPS59532A - Supercharger for four-cycle internal-combustion engine - Google Patents

Abstract

PURPOSE:To enable an efficient supercharging operation by a method wherein a clearance is formed within a sealed crankcase so as to communicate with the latter and a flexible section which responds to the fluctuation of the pressure in the cranckcase so that a sucked gas mixture is pressurized by the fluctuation of the pressure in the crankcase. CONSTITUTION:In the compression stroke, the pressure in a crank chamber 7 becomes negative due to the upward movement of a piston 11 and the fuel gas mixture from a carburettor is sucked into a supercharging chamber 14 through a one way valve 19. In the explosion stroke, the pessure in the crank chamber 7 becomes positive and the gas mixture is discharged into a downstream air intake passage 18 through a one way valve 20. In this case, an intake valve for establishing or interrupting communication between the pasage 18 and the combustion chamber is closed so that the gas mixture fills the passge 18. In the exhaust stroke, the gas mixture is sucked into the supercharging chamber 14 so as to be supercharged into the combustion chamber as the gas mixture for effecting two strokes of the engine, together with the gas mixture fed into the passage 18 during the combustion stroke.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a simple supercharging device for a four-stroke internal combustion engine.

More specifically, a space is provided in the sealed crankcase that communicates with the closed crankcase, and a flexible part is provided within this space that responds to pressure fluctuations within the crankcase, so that the intake air-fuel mixture is controlled by the pressure fluctuations within the case. The present invention relates to a supercharging device for pressurizing and supercharging.

2. Description of the Related Art A supercharging device that pressurizes an intake air-fuel mixture and supplies it to a combustion chamber is known as a means for increasing the output of an internal combustion engine of a vehicle or the like.

As shown in Japanese Patent Application Laid-Open No. 51-37316 or Japanese Utility Model Application No. 51-11940, such a filtration feeding device is generally provided in the form of a compressor that is driven by engine output separately from the engine, or The exhaust gas is used to drive a turbine for supercharging purposes. Such a supercharging device has a complicated and expensive structure, increasing the cost of the engine.

Therefore, a method has been proposed in which the purpose of supercharging is achieved by utilizing the pressure fluctuations in the crank chamber, that is, the positive and negative pressure generated by the reciprocating motion of the piston. According to this, it is possible to easily obtain a supercharging system. I can do it. And in this case,
It is necessary to prevent the supply of oil-containing mixture into the combustion chamber. For this reason, the
04 or Japanese Unexamined Patent Publication No. 53-76212 are known.

However, in Japanese Patent Publication No. 50-37804, in order to supercharge the combustion chamber through an intake passage communicating with the crank chamber, an oil passage is formed inside the crankshaft, connecting rod, etc., and its processing is difficult. It's extremely troublesome. Furthermore, in JP-A No. 53-76212, an excess air supply pipe connects the crank chamber and an intake passage equipped with a check valve, and an oil separation member is provided in the supply pipe to prevent oil from entering. However, it has the disadvantage of not being able to completely separate the oil.

Furthermore, in Utility Model Application No. 50-60414, a diaphragm device was previously installed in the crank chamber, and check valves were installed upstream and downstream of this diaphragm device to allow outside air to flow during negative pressure in the crank chamber (during compression and exhaust strokes). A device is shown that purifies the exhaust gas by inhaling the air into the device and introducing outside air into the exhaust passage during positive pressure (during the suction and explosion strokes); The air-fuel mixture is compressed and filled into the passage, and the compressed air-fuel mixture for two strokes is supercharged into the combustion chamber during the intake stroke (in order to use it as a supercharging device, an additional mechanism is required. Become.

An object of the present invention is to provide a simple supercharging device that can perform supercharging reliably and effectively by utilizing pressure fluctuations within the crankcase, and where lubricating oil or the like is present within the crankcase. To provide a simple supercharging device that can reliably achieve the purpose of supercharging without being affected by contamination or contamination.

Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. This will reveal further objects and advantages of the invention.

FIG. 1 is a longitudinal cross-sectional view of a main part of an engine including a supercharging device according to the present invention, and 1 is a crankcase consisting of left and right halves 1a and 1b. Between the halves 1a and Ib of the crankcase 1, journal parts 2a and 2a of the crankshaft 2 are connected to a bearing 3.
The pin portion 2b of the crankshaft 2 is connected to a piston 6 fitted in a cylinder 5 via a connecting rod 4. A sealed crank chamber 7 is formed within the crankcase 1 described above.

A cylindrical extending portion 8 may be integrally formed on the side of one half 1b of the crankcase 1, or the extending portion 8 may be formed separately and integrated. The outer end of this 8 is closed with a lid 9, and the inner end of the extending portion 8 is open to communicate with the inside of the crank chamber 7, and the inner end of the extending portion 8 and the crank chamber 7 are bordered. A frame-shaped stopper portion 8a is provided at the portion. Thus, a space 10 is provided within the extending portion 8 that communicates with the inside of the crank chamber γ.

A piston 11, which is a sliding partition member, is loosely fitted in this space 10, and the stopper portion 8a is attached to the end of the piston 11.
A stepped portion 11a that engages with the skirt portion 11 is provided on the outer periphery of the skirt portion 11.
b has a size that fits within the space 10.

A stopper rubber 12 is protrudingly provided on the inner periphery of the intermediate part or the part near the outside of the extension part 8, and the stopper rubber 12 and the skirt part 11b of the piston 11 are connected by a bellows 13, and thus the piston 11 A supercharging chamber 14 airtightly partitioned from the space 10 by a bellows 13 is provided in the space 10.

A return spring 15 is interposed between a spring stopper 9a protruding from the inner surface of the center portion of the lid body 9 and a ring-shaped spring stopper 11C protruding from the back surface of the piston 11.

On the other hand, a suction pipe 16 is connected to the outer surface of the lid body 9.
6 is divided by a partition wall 16a into an upstream suction passage 17 that communicates with the carburetor side (not shown) and a downstream suction passage 18 that communicates with the combustion chamber side by controlling the opening and closing of a known suction valve (not shown). The upstream and downstream suction passages 17.18 are mutually divided by the partition wall 16a and the outer surface of the lid body 9, and valve holes 11 and 12 are formed in the portions of the lid body 9 corresponding to the upstream and downstream suction passages 17.18.
7a and 18a, each upstream and downstream suction passage 17.18
The inside of the supercharging chamber 14 is communicated with the inside of the supercharging chamber 14 through valve holes 17a and 18a. A suction side one-way valve 19 such as a reed valve 19 that opens and closes the valve hole 1γa of the upstream suction passage 17 to obtain a sufficient suction flow rate is installed on the inner surface of the supercharging chamber 14 of the lid 9. 9
The outer surface facing the downstream suction passage 18 has an IJ that opens and closes the valve hole 18a of the downstream suction passage 18 to obtain a sufficient discharge flow rate.
A one-way valve 20 on the discharge side, such as a + door valve 20, is provided respectively.

In the above, the supercharging piston 11 reciprocates within the space 10 due to positive and negative pressure fluctuations within the crank chamber 7.

That is, the inside of the crank chamber 7 becomes positive pressure during the suction and explosion strokes of the engine, and when the pressure is positive, the supercharging piston 11 is moved by the spring 1.
5 to the left in the drawing, the volume inside the supercharging chamber 14 is reduced, and the air-fuel mixture sucked into the chamber 14 is compressed. The compressed air-fuel mixture opens the exhaust side one-way valve 20 which is provided to open in the compression direction with respect to the valve hole 18a, and the downstream suction passage 18 is opened.
and is supplied to the combustion chamber when the intake valve opens. In this case, the suction side reed valve 19 closes the suction side valve hole 17a since this is the closing direction.

On the other hand, the inside of the crank chamber 7 becomes negative pressure during the compression and exhaust strokes of the engine, and the piston 11 slides rightward in the figure due to this, but this sliding is urged by the spring 15 and slides quickly. The volume car increases and the volume inside the supercharging chamber 14 increases rapidly, and this causes the suction side one-way valve 19 to close due to negative pressure.
is open (.Thus, the upstream suction passage 17 communicating with the carburetor and the chamber 14 communicate via the striped valve hole 17a, and the air-fuel mixture flows into the chamber 1.
It is effectively and efficiently inhaled within 4 days. Continued (crank chamber 7
Due to the positive pressure of Passage 1
8 and is supplied to the combustion chamber when the intake valve opens.

The above operation will be explained in the order of strokes of the four-stroke internal combustion engine.

In the compression stroke, the inside of the crank chamber 7 becomes negative pressure as the piston 11 rises, and the fuel mixture from the carburetor is sucked in through the one-way valve 19 on the suction side. In this case, the supercharging chamber 14 is in a contracted state during the suction stroke of the previous stroke, so that sufficient volume remains in the expansion direction.

During the explosion stroke, the pressure inside the crank chamber 7 becomes positive as the piston 11 descends, and the air-fuel mixture sucked into the supercharging chamber 14 during the compression stroke is transferred to the downstream intake passage on the combustion chamber side via the one-way valve 20 on the discharge side. It is discharged on 18th.

In this case, the suction valve that controls opening and closing of communication between the downstream suction passage 18 and the combustion chamber is closed, and the discharged air-fuel mixture is compressed into the downstream suction passage 18 between the suction valve and the one-way valve on the discharge side of the supercharging chamber. Filled with condition.

In the exhaust stroke, as the piston 11 rises, the inside of the crank chamber 7 becomes negative pressure, and the air-fuel mixture from the carburetor is sucked in again via the one-way valve 19 on the suction side.

At this time, during the explosion stroke, the suction valve and the one-way valve 20 on the discharge side of the supercharging chamber
The air-fuel mixture filling the downstream suction passage 1B between them is kept compressed as it is.

In the suction stroke, the pressure inside the crank chamber 7 becomes positive due to the downward movement of the piston 11, and the air-fuel mixture sucked in in the exhaust stroke is compressed and discharged from the supercharging chamber 14 via the discharge side one-way valve 20, and the air-fuel mixture is discharged from the downstream suction passage. At 18, the mixture is supercharged into the combustion chamber together with the mixture that was compressed and filled during the explosion stroke as a mixture for two strokes of the engine.

A supercharging chamber that responds to pressure fluctuations in the crank chamber is installed in a space that communicates with the crank chamber in a sealed state with a variable volume and that responds to pressure fluctuations in the crank chamber.Special equipment and equipment are required to prevent lubricant oil from entering the crank chamber and the suction passage. This can be prevented by simply configuring the supercharger itself without any modification. Therefore, it is possible to prevent lubricating oil from entering the suction passage and causing white smoke from the exhaust gas without any special equipment or processing.

In addition, while making use of pressure fluctuations within the crank chamber, the supercharging chamber is separated from the crank chamber, allowing the volume of the supercharging chamber to be set to match the displacement of the engine, thus making the crank chamber itself the supercharging chamber. The amount of residual air-fuel mixture in the supercharging chamber can be kept extremely small compared to conventional turbocharging chambers, and the desired mixture ratio can be obtained without fear of dilution of the air-fuel mixture. Operation status can be obtained.

Furthermore, as in the embodiment (in the case where the supercharging chamber is a piston type), it is possible to construct a supercharging device by optimally setting the pressure receiving area and stroke of the supercharging chamber to account for the volume change due to the vertical movement of the piston, etc. Demonstrates the effect of

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view, and FIG. 2 is an end view taken along line 2-2 in FIG. 1. In the drawing, 1 is a crankcase, 14 is a space, 11 is a partition, 16 is a suction pipe, 17 is an upstream suction passage, 18 is a downstream suction passage, 19 is a one-way valve on the suction side, and 20 is a one-way valve on the discharge side. It is.

Claims (1)

[Claims] In a four-stroke internal combustion engine with a closed crank chamber that includes a supercharging device in the intake passage downstream of the carburetor, the supercharging device includes:
In a space communicating with the crank chamber, a variable-volume supercharging chamber is formed in a sealed state with the crank chamber by a flexible portion that responds to pressure fluctuations in the crank chamber due to vertical movement of a piston of the engine, The suction passage downstream of the carburetor and the supercharging chamber are connected to each other via an intake one-way valve that opens in response to negative pressure in the crank chamber when the piston rises, and the supercharging chamber and the combustion chamber are connected in communication. A supercharging device for a four-stroke internal combustion engine, characterized in that the side and intake passage are connected to each other via an exhaust one-way valve that opens in response to positive pressure in the crank chamber when the piston descends. .