Other

Kokusan Parts Industry Co., Ltd.

Koichi Hatamura

Takashi Suzuki

Takahiko Sugiura

Hiroyuki Ogino

Masahisa Kumashiro

Keisuke Umehara

Yasuyuki Okudaira

Takeshi Wakuda

Reiji Mahigashi

A four-stroke engine () structured to introduce fresh air and EGR gas into a cylinder () includes a blowdown supercharging system () using a combustion chamber internal pressure when exhaust valves open in an expansion stroke of a first cylinder (hereinafter denoted as an exhaust blowdown pressure) for introducing EGR gas into a second cylinder from near a bottom dead center of an intake stroke to near a bottom dead center of a compression stroke of the second cylinder which is different from the first cylinder in combustion timing, and a secondary air supply system () supplying secondary air to an exhaust port () of the second cylinder prior to arrival of the exhaust blowdown pressure at the second cylinder. The secondary air in the exhaust port and the EGR gas are supercharged into the second cylinder by the exhaust blowdown pressure from the first cylinder.

Secondary air and exhaust gas recirculation for a four-stroke internal combustion engine

An average pressure Pin an exhaust port at an overlap period Tduring which a period Tduring which an exhaust valve of a first cylinder unit is in an EGR opening state overlaps with a period Tduring which an intake valve of the first cylinder unit is in an opening state is set to be lower than an average pressure P' in the exhaust port within the EGR opening period Tand after a lapse of the overlap period T, or an overlapped opening time area Sat the overlap period Tis set to be not more than one-fourth of an opening time area Sat the EGR opening period T

Four-cycle engine

The present invention provides an engine capable of increasing an introducing amount of an EGR gas without reducing an introducing amount of a fresh air. In an engine structured to introduce fresh air and an EGR gas into a cylinder, the EGR gas is introduced into the cylinder at least at a part of a compression stroke using a pressure in a combustion chamber at least at a part of a power stroke.

Engine

A metal gasket capable of preventing the occurrence of cracks in a stopper while employing a wave-shaped stopper, improving the contact pressure balance around the bead to enhance the engine performance, and improving the durability of the stopper. The metal gasket is constituted by a gasket component sheet having an opening formed to face a combustion chamber, and the gasket component sheet is provided with a combustion chamber bead surrounding the opening. An inner circumference side stopper lower than the height of the combustion chamber bead is formed along the combustion chamber bead in a portion between the combustion chamber bead and the opening such that at least a section of each wave where stress amplitude is large becomes thin, a thin portion and a thick portion are arranged alternately in each wave, and the hardness of the thin portion is higher than that of the thick portion.

Growing community of inventors

Yachiyo, Japan

Koichi Hatamura