JPH0893549A - Piston with saved front surface area - Google Patents

Abstract

PURPOSE: To improve combustion efficiency by extending top lands on both side parts of a piston upward. CONSTITUTION: A piston 3 in an engine is formed into a shape wherein top lands 1 on both sides of the piston project upward from a head gasket in the top dead center by extending the top lands 1 on the part upward in order to eliminate recessed parts on both sides of the piston. Moreover, a combustion chamber 4 is so formed as to match the shape of the piston 3. In the piston 3 including a cylinder, the front surface area on the combustion chamber is decreased, so as to improve combustion efficiency. Moreover, combustion pressure can be efficiently converted to axial output by decreasing gas leakage from the recessed parts on both sides of the piston.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention aims to improve the combustion efficiency of an engine. (B) Prior art The top end of the top land of the piston is on the same plane over the entire circumference of the piston unless a notch is formed by the recess. Combustion efficiency is improved by reducing the surface area of the piston on the combustion chamber side. The power is improved by reducing the leakage of combustion gas from around the piston. (C) Problems to be solved by the invention The piston shape according to the conventional technology has few irregularities when viewed as a single piston, but considering the cylinder as well, the central portion of the piston has a convex shape in order to increase the compression ratio. A recess (2) is formed on both sides of the piston, which is a cause of deterioration of combustion efficiency (Fig. 3). Combustion gas easily leaks from the recesses (2) on both sides of the piston and becomes blow-by gas (Fig. 3). (D) Means for solving the problem In order to eliminate the recesses (2) on both sides of the piston, the top land (1) of that part is extended upward. Top land (1) on both sides of the piston at top dead center
The shape projects above the head gasket. The combustion chamber (4) is shaped to match the piston shape. (E) The piston shape including the working cylinder reduces the surface area on the combustion chamber side and improves combustion efficiency. Gas leakage from the recesses (2) on both sides of the piston is reduced by adopting the shape (1) of the present invention, so that the combustion pressure can be efficiently converted into a shaft output.

[Brief description of drawings] FIG. 1 is a perspective view showing an embodiment of the present invention. FIG. 2 is a sectional view of the present invention. Fig. 3 is a sectional view of a conventional piston 1 is the top land extended upward 2 is the concave part on both sides of conventional piston 3 is the piston of the present invention 4 is a combustion chamber matched to the piston shape of the present invention 5 is a conventional piston 6 is a conventional combustion chamber

[Procedure amendment] [Date of submission] February 13, 1993 [Procedure amendment 2] [Document name for amendment] Drawing [Item name for amendment] Figure 1 [Method of amendment] Change [Content of amendment] [Figure 1] [Procedure amendment 3] [Document name to be amended] Drawing [Item name to be amended] Figure 2 [Correction method] Change [Content of amendment] [Figure 2]

Claims (1)

[Claims] 1. Piston shape with top land (1) on both sides of the piston extended upward. 2. 2. The piston shape according to claim 1, wherein the top land (1) extending upward has a continuous profile shape without steps. 3. The upper side in claim 1 is the head direction.