JPH0313552Y2 - - Google Patents

Description

[Detailed description of the invention] The purpose of this invention is to reduce the gas flowing toward the crank chamber by releasing the gas pressure between the top piston ring and the second piston ring to the piston head side, thereby reducing blow-by gas. It is something to do.

Normally, a piston uses three to four piston rings, and each piston ring has its own role. The top piston ring has the role of blocking combustion gas at the highest temperature and highest pressure, but the combustion gas leaking from this top piston ring is blocked by the second piston ring, so it immediately escapes downward. I can't. As the combustion gas leaks one after another during each compression explosion stroke, a high pressure of approximately 20 kg/cm ² is maintained between the top piston ring and the second piston ring, which gradually leaks into the crank chamber and causes blow-by. It has become gas.

On the other hand, there is some margin between the piston ring width and the ring groove width, and the piston ring can move up and down within the ring groove by the margin. The movement of the top piston ring in the ring groove is caused by the frictional force between the piston ring and the inner surface of the cylinder, the pressure at the top of the top piston ring, that is, the top land, the pressure between the top piston ring and the second piston ring, that is, the second land, and the inertia of the ring. controlled by power. In other words, the behavior of the top piston ring within the ring groove changes depending on the intake stroke, compression stroke, explosion stroke, and exhaust stroke.In the explosion stroke, it is at a low position, but in the latter half of this stroke, the balance of the above factors changes. The pressure in the second land becomes greater than the pressure in the combustion chamber, so it is pushed upwards. At this time, oil is blown away into the combustion chamber along with the gas, increasing oil consumption. The top piston ring remains pushed up until the exhaust and intake strokes. However, the pressure in the second land gradually decreases and during the intake stroke, the top piston ring is pushed down, and the compression and explosion strokes remain depressed.

The appropriate period for releasing the gas pressure in the second land to the piston head side coincides with the time when the top piston ring is rising. For example, it cannot be extracted during the compression explosion stroke, but it is suitable for extraction from the latter half of the exhaust stroke to the first half of the intake stroke.

That is, in the present invention, the hole is formed diagonally from the lower part of the top piston ring cross section to the part that is blocked by the ring groove, and the upper part to the empty part between the piston and cylinder. We were able to achieve the goal of removing gas and eliminating ring behavior during the explosion stroke of the top piston ring.

Examples will be described with reference to the drawings. Fig. 1 is an explanatory view when the top piston ring is on the lower side of the groove, and Fig. 2 is an explanatory view when it is on the upper side. Arrows indicate gas flow. 1 is the inner surface of the cylinder, 2 is the piston, and a top piston ring 3 slides on the inner surface 1 of the cylinder. The top piston ring 3 can move up and down within the ring groove 4. Reference numeral 5 denotes a hole that communicates the upper and lower surfaces of the top piston ring 3, the upper opening of the hole communicates between the cylinder inner surface 1 and the piston 2, and the lower opening is located at a position where it is closed by the lower surface of the groove 4. It is becoming. The part between the cylinder inner surface 1 and the piston 2 and below the top piston ring 3 is the second land.

Figure 1 shows the ring groove 4 of the top piston ring 3.
The upper combustion gas cannot leak through this hole 5 to the lower second land 6. That is, during the explosion period, the gas leakage passage area of the top piston ring 3 remains the same as in the prior art. However, when the top piston ring 3 is in contact with the upper surface of the ring groove 4 as shown in FIG. 2, the lower opening of the hole 5 is separated from the lower surface of the ring groove 4, and the gas accumulated in the second land 6 is The blow-by gas can escape upward through the hole 5 and return to the combustion gas, reducing the pressure in the second land 6 and reducing the amount of blow-by gas leaking into the crank chamber.

The diameter of the holes only needs to be very small, and the number of holes is determined by the size of the engine, but the present invention is extremely effective in reducing blow-by gas and greatly contributes to improving engine efficiency. It is.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of gas flow when the top piston ring of the present invention is in contact with the lower surface of the ring groove, and FIG. 2 is an explanatory diagram of the gas flow when the top piston ring of the present invention is in contact with the upper surface. 1... Cylinder inner surface, 2... Piston, 3...
Top piston ring, 4...Ring groove, 5...
Hole, 6...second land.

Claims (1)

[Scope of utility model registration request] Among the piston rings used in internal combustion engines, the top piston ring has an oblique hole that is always open between the piston and the inner surface of the cylinder on the upper surface, and that opens in a portion that can be closed by a ring groove on the lower surface. Features piston rings.