JPS60224935A - Supercharging device for four-cycle engine - Google Patents

Abstract

PURPOSE:To make suction to a cylinder performable with supercharging pressure commensurate to a volumetric variation in an air charging chamber with a vertical motion of a piston, by forming the air charging chamber to be comparted by a partition wall installed interposingly between the cylinder and a crankcase, in the underside of a skirt part of the piston. CONSTITUTION:An intermediate rod 10, extending downward in the axial direction of a cylinder and being connected to a cone rod 4, is hangingly installed in a piston 3, while a partiton wall 11 into which the intermediate rod 10 is slidably inserted is installed interposingly between the cylinder and a crankcase 2, and an air charging chamber 12 is formed up. And, the air charging chamber 12 is made to interpose in a suction passage 13 of the cylinder, and each check valve is installed in both inlet and outlet sides of the passage 13. With this constitution, an air-fuel mixture out of an ustream part of the suction passage 13 leading to a carburetor is fed to a downstream part 13b of the suction passage 13 leading to a suction valve 7 through the check valve, the air-charging chamber 12 and a check valve 15. And, the supercharging pressure required is secured by a volumetric vibration in the air-charging chamber 12 with a vertical motion of the piston 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a supercharging device for a four-stroke engine, and more specifically, to a supercharging device for a four-stroke engine, and more specifically, to a supercharging device that can obtain a supercharging function by utilizing the vertical movement of a piston without using a pump-type supercharger. This article relates to a supercharging device.

As a conventional device of this type, Japanese Patent Publication No. 50-37804 discloses, for example, a system in which a 360° phase difference metal is attached to both cylinders of a 4-cycle two-cylinder engine, and a check valve is installed in the crankcase when the pistons of both cylinders rise. It is known that the engine takes in all the air and, when the piston descends, compresses the air in the case and sends it under pressure to the cylinder on the side of the full intake stroke to obtain a supercharging function, but this type is limited to multi-cylinder engines. In addition, in order to prevent lubricating oil from entering the intake air, the oil reservoir v must be isolated from the internal space of the crankcase, and oil seals must be installed at each lubrication point, making the structure of the lubrication system complicated. This is accompanied by the inconvenience of

An object of the present invention is to provide a supercharging system that can be applied to a single-cylinder engine and that can easily prevent lubricating oil from entering the intake air. An intermediate iron extending downward in the direction and connected to the connecting rod is vertically provided, and a gap mt-interposed between the cylinder and the crankcase below the intermediate iron so that the intermediate iron is slidably inserted, An air supply chamber partitioned by the partition wall is formed below the skirt portion of the piston, and the air supply chamber is interposed in the intake passage of the cylinder to allow gas to flow into the air supply chamber at its inlet side. The present invention is characterized in that a first check valve is provided on the outlet side thereof, and a second check valve is provided on the outlet side thereof to allow gas to flow out from the air supply chamber.

The present invention will be explained below with reference to the illustrated embodiments.

In the drawing, (1) is a cylinder, and (2) is the cylinder (1).
This is the lower crankcase of the crankcase (2).
) supports a crankshaft (5) connected to a piston (3) in the cylinder (1) via a connecting rod (4), and a cylinder head (
6), the intake and exhaust valve 17) t8), and the crankshaft (5)
Kanben cam (9) connected via chain (9a) to
As a whole, an overhead cam valve type four-stroke single-cylinder engine was constructed.

According to the characteristics of the present invention, the piston (
3), an intermediate rod (11) extending downward in the axial direction of the cylinder (1) and connected to the connecting rod (4) is installed vertically, and the intermediate rod (11) is installed vertically between the cylinder (1) and the crankcase (2). A partition wall (II) k into which a rod QI is slidably inserted is interposed to form an air supply chamber Q21' partitioned by the partition wall Uυ below the skirt portion (3a) of the piston (3). , the intake passage (13) of the air supply chamber agt (the cylinder), and a first check valve I consisting of a closed valve that intervenes in the intake passage (13) and allows gas to flow into the air supply chamber 03 on its inlet side; A second check valve Q9 is provided on the outlet side to allow gas to flow out from the side of the air supply chamber U, and gas is mixed from the upstream portion (13a) of the intake passage (13) leading to the carburetor (not shown). Check the first check valve u4)-
+ Supply air is supplied to the intake valve (the downstream part of the intake passage Q3 that lags behind the force <13b) through the second check valve (11 threads).In addition, in a fuel injection type engine, Alternatively, a sudden air may be supplied through the thread path to inject fuel near the intake valve (7).

The intermediate rod Q (1) can be integrally molded with the piston (3), but in the illustrated example, it is formed by a nozzle separate from the piston (3), and its upper and lower ends are The piston (3) and the conorod (4) are connected to each other via pins (Oa) (10b) at the section, and a guide sleeve (lla) 'r is integrally molded at the center of the partition wall aυ. The intermediate rondo QI on the sleeve (Ila)
Pressure was applied so that it could be slid into place.

In the illustrated example, a relatively small-diameter trap 9 is formed over substantially the entire length of the skirt portion (3a), and upper and lower oil rings Q19 of the skirt portion (3a) are formed between the inner wall surface of the cylinder (1) and the inner wall surface of the cylinder (1). (Lubricating oil flow gap o sealed by l[9
n' and a piston (
In the stroke range of 3), an oil supply port 08 connected to the oil pump (not shown) and an oil drain port connected to the inside of the crankcase (2) are formed so as not to come out of the gap (17). , the piston (3) can be lubricated while preventing the lubricating oil from entering the air supply chamber a4, and the gap αη and the inside of the intermediate rod αq can be lubricated by the oil in the upper part of the piston (3). The hole (21 gold) communicates with the bottle (10b) at the lower end of the intermediate rod 4 and the guide sleeve (l
La) The sliding surface can be completely lubricated.

In the drawings, υQυ indicates seal rings provided above and below the intermediate rod a1.

Next, the effects of the present invention will be explained based on the above examples.
First, due to the volume expansion of the air supply chamber α2 due to the upward movement of the piston (3) during the compression stroke, the air-fuel mixture is sucked into the air supply chamber α2 from the upstream portion (13a) of the intake passage α through the first check valve 04. The upper hook of the piston (3) during the explosion stroke opens the chamber Q.
The air-fuel mixture in the air-fuel mixture in the air-fuel mixture is pushed out to the downstream part (13b) of the intake passage 0 through the second check valve 09, the pressure of the air-fuel mixture is accumulated in this part (13b), and then the air-fuel mixture in the exhaust stroke is pushed out to the downstream part (13b) of the intake passage.
3) In the upward movement, the air-fuel mixture is sucked into the chamber 0 through the first check valve Q4 in the same way as in the compression stroke, and in the intake stroke, the air-fuel mixture in the chamber a2 is sucked into the second check valve Q4. via the downstream portion (13b
), and the air-fuel mixture previously stored in pressure as described above is press-fitted into the cylinder (1),
In this way, the supercharging function is demonstrated.

Here, if a conventionally known pump-type over-MI machine is used,
The Fi supercharging function decreases in the low speed range, but in the present invention, intake is performed at a constant supercharging pressure according to the volume change of the air intake chamber a2 regardless of the engine rotation speed, and sufficient supercharging is achieved from the low speed range. The supply function can be fully utilized.

As described above, according to the present invention, the entire air supply chamber is formed under the skirt portion of the piston and is partitioned by a partition wall interposed between the cylinder and the crankcase, and the air supply chamber is closed by the vertical movement of the piston. This system allows air to be taken into the cylinder at supercharging pressure that corresponds to volume changes, and is simpler and cheaper than when using a pump-type supercharger. Unlike the conventional example mentioned above, a supercharging function can be obtained even with a single cylinder engine, and since the air supply chamber is separated from the internal space of the crankcase by a partition wall, This prevents lubricating oil that is scattered from oil reservoirs in the case and lubricating points around the crankshaft from entering the air supply chamber, and an oil ring on the skirt prevents lubricating oil from entering from the sliding surfaces of the piston and cylinder. If this is prevented by providing a lubricant, it is possible to effectively prevent problems such as the generation of white smoke due to the mixing of lubricating oil into the intake air, and the structure of the lubricating system can also be simplified.

[Brief explanation of the drawing]

Fig. 1 is a cut-away front view of a four-cycle engine equipped with the device of the present invention at the end of the compression stroke, Fig. 2 is a side cross-sectional side view taken along the line ■-■ in Fig. 1, and Fig. 3 is a cut-away side view at the end of the intake stroke. It is. (1)...Cylinder (2)...Crankcase (
3)...Piston (3a)...Skirt part (41)
... Connecting rod (1G ・= intermediate rod ■ ... air supply chamber of bulkhead a (+3 ... intake passage ■ ... first
Check valve 09...Second check valve patent IBM person 2 people outside Honda Motor Co., Ltd.

Claims (1)

[Claims] An intermediate rod extending downward in the axial direction of the cylinder and connected to the connecting rod is vertically disposed on the piston, and a partition wall in which the intermediate rod is slidably inserted between the cylinder and the crankcase below the cylinder is interposed. An air supply chamber partitioned by the partition wall is formed on the lower side of the skirt portion of the piston, and the air supply chamber is interposed in the intake passage of the cylinder, and an air supply chamber is provided on the inlet side of the air supply chamber. A supercharging device for a four-cycle engine, characterized in that a first check valve that allows gas to flow in, and a second check valve that allows gas to flow out from the air supply chamber are provided on the outlet side thereof.