JPS5820386B2 - Kiyuki Benz Kipiston Osona Etaninen Kikan - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION An example of the intake and exhaust stroke of a conventional four cycle internal combustion engine will be explained with reference to FIG.

First, when the piston 2, which is in the expansion stroke after completion of combustion in the cylinder 1, approaches the bottom dead center, the exhaust valve 3 begins to open and the gas in the cylinder is discharged to the exhaust pipe 4.

The changes in the power of each part at this time are as shown in Figure 2. The pressure in the cylinder drops rapidly from point A when the exhaust valve 3 begins to open, while the pressure in the exhaust pipe increases from point B, causing the piston 2 to move downward. At the zero point immediately after passing the dead center, the difference in pressure between the two becomes △Pe.

This ΔPe is a pressure loss that occurs at the exhaust valve 3 when exhaust gas flows out from the cylinder interior 1 to the exhaust pipe 4, and this ΔPe is approximately constant in the exhaust stroke after the zero point.

That is, △Pe is the pressure loss that occurs because the opening area of the exhaust valve 3 is not sufficient, and in high-speed engines, the opening area becomes relatively small compared to the piston speed, so △P
e becomes larger.

Similar to this exhaust stroke, in the intake stroke as well, the pressure in the cylinder 3 is lower (ΔPs) than the pressure in the intake pipe 6 due to the pressure loss that occurs in the intake valve 5.

The above-mentioned ΔPe and ΔPs are the main factors, and in the supply and exhaust stroke of a four-cycle engine, the supply and exhaust pump losses shown by diagonal lines in FIG. 3 occur.

That is, X, which occurs due to insufficient opening area of the exhaust valve 3,
The sum of Y caused by the insufficient opening area of the air supply valve 5 and Z due to the increase in pressure inside the exhaust pipe 4 (X + Y + - Z) is the pump loss in the supply and exhaust process, and the effective output of the piston is this As a result, thermal efficiency decreases.

In order to reduce this pump loss, △Pe and △Ps can be reduced, which means increasing the opening area of the exhaust valve 3 and the air supply valve 5. Since the area of the lower surface of the cylinder 7 shown in FIG. 1 is limited, it has been impossible to further increase the opening area of the supply and exhaust valve.

The present invention was proposed in order to solve the above-mentioned conventional drawbacks, and the piston is provided with an air supply valve, and the air supply passage to the air supply valve is communicated with the atmosphere or the air supply pipe only through the air supply hole of the cylinder. The air supply hole of the piston and the air supply hole of the cylinder are communicated with each other throughout the entire piston stroke, and the opening area of the air supply valve and the exhaust valve is made larger than that of the conventional one. It is an object of the present invention to provide an internal combustion engine equipped with a piston equipped with an air intake valve, which can reduce pump loss in air supply and exhaust, and improve thermal efficiency.

The embodiments shown in the drawings will be described below. FIG. 4 shows an embodiment of the present invention, in which the piston 8 has an air supply hole 9 that communicates from the top surface to the side surface, and an opening of the air supply hole 9 to the top surface of the piston that can be opened and closed. An air supply valve 10 is provided.

The air supply valve 10 is guided by a valve stem guide 11 and is seated by a valve spring 12 on a valve seat provided on the piston 8 .

13 is the cylinder of the piston 8, and an air supply pipe (
An air supply hole 14 is provided which communicates with the combustion chamber 15 (not shown), and exhaust holes 17 and 17' are provided in the wall of the combustion chamber 15 of the cylinder head, which are opened and closed by exhaust valves 16 and 16'.

As mentioned above, in FIG. 4, the intake valve 5 in FIG. 1 is replaced by the exhaust valve 16.
', the air supply pipe 6 is used as the exhaust pipe 17', and since there are two exhaust valves 16 and 16', the opening area of the exhaust valve is approximately twice that of the case shown in Fig. 1, and the cylinder The air supply hole 14 of the piston and the combustion chamber 15 communicate only through the air supply hole 9 of the piston.

Next, the effect will be explained.

When the piston 8, which is in the expansion stroke after completion of combustion in the combustion chamber 15, approaches the bottom dead center, the exhaust valves 16, 16' open and the combustion chamber 15
Internal gas is discharged to exhaust pipes 17, 1γ.

When the piston 8 moves further and passes the bottom dead center, it enters the exhaust stroke (piston rise).

Note that during the expansion and exhaust strokes, the pressure inside the combustion chamber is higher than the pressure inside the air supply pipe, so the air intake valve 10 is in close contact with a valve seat provided on the piston 8.

Then, as the exhaust stroke progresses and the piston approaches top dead center, the pressure in the combustion chamber decreases.

When this pressure further decreases and becomes smaller than the supply air pressure and becomes greater than the force of the push-up spring 12 acting on the intake valve 10, the intake valve 10 automatically opens and the air is supplied into the combustion chamber 15. Qi is done.

Next, when the piston 8 passes the top dead center and enters the intake stroke (piston descent), the exhaust valves 16, 16' are closed by the action of an exhaust cam (not shown), so the inside of the combustion chamber 15 expands, and the inside of the combustion chamber 15 expands. Since the pressure tends to decrease, the air supply valve 10 continues to open due to the supply pressure, and the supply air is diverted.

When the air supply stroke approaches the end and the pressure in the combustion chamber approaches the supply pressure, the force acting in the direction of opening the air intake valve 1o becomes weaker, and the air intake valve 10 is automatically closed by the force of the valve spring 12.

When the intake stroke ends and the compression stroke begins, the pressure inside the combustion chamber becomes higher than the intake pressure, so the combustion and expansion strokes proceed with the intake valve 10 closed, allowing the internal combustion engine to cycle without any problems.

As explained in detail above, the present invention is provided with an air supply valve on the piston, and the area of the upper surface of the piston is approximately the same as the lower surface of the cylinder where the air supply and exhaust valve is provided in conventional engines. The opening area of the air supply valve can be approximately twice that of conventional engines.

Further, since the exhaust valve can use a conventional air supply valve as the exhaust valve and have two exhaust valves, the opening area of the exhaust valve can also be made about twice that of the conventional engine.

As described above, in the present invention, the opening area of the air supply valve and the exhaust valve is approximately twice that of the conventional engine, so that the pump loss of air supply and exhaust can be reduced and the thermal efficiency can be improved.

Furthermore, when the opening area of the exhaust valve is doubled, the pressure loss ΔPe in the exhaust valve section is proportional to the square of the flow rate of the working gas flowing through the exhaust valve section, so that ((-)2=+).

Similarly, the pressure loss △Ps in the air supply valve section will be about 10, so in Figure 3, X and Y will be H, but Z will not change, so the overall pressure loss will be about %. We can expect that.

By the way, in a conventional engine, the pump loss is about 10% of the effective output, so the thermal efficiency of the present invention can be improved by about 5% compared to the conventional engine.

Note that if the air supply valve of the piston is an automatic valve, the gas inside the cylinder will not flow back into the air supply passage completely, and there is no risk of contaminating the air supply passage.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of a conventional four-stroke internal combustion engine, and FIG. 2 is a cross-sectional view of the internal combustion engine shown in FIG. FIG. 3 is a diagram showing changes in cylinder pressure during the intake and exhaust stroke of an internal combustion engine, and FIG. The front sectional view, FIG. 5, is a sectional view taken along the line D--D in FIG. 4. Explanation of the main parts of the diagram, 8...Piston, 9...
...Air supply hole, 10...Air supply valve, 13...
...Cylinder, 14...Air supply hole, 15...
... Combustion chamber, 16, 16' ... Exhaust valve, 17
, 17'...Exhaust hole.

Claims (1)

[Claims] 1. The piston is provided with an air supply hole that constantly communicates from the top surface to the side surface of the piston, and an air supply valve that opens and closes the opening of the air supply hole to the top surface of the piston based on the pressure difference between the pressure inside the air supply hole and the pressure in the combustion chamber, An air supply hole that communicates with the air supply pipe is provided in the side wall of the cylinder into which the piston is fitted, and an exhaust hole that is opened and closed by an exhaust valve is provided in the combustion chamber wall of the cylinder head, and the air supply hole of the cylinder and the combustion chamber are A piston with an air supply valve, characterized in that the air supply hole of the piston communicates with the air supply hole of the cylinder only through the air supply hole of the piston, and the air supply hole of the piston and the air supply hole of the cylinder communicate throughout the entire piston stroke. internal combustion engine.