Mazda Motor Corporation

Takehiko Yasuoka

Hiroyuki Yamashita

Hiroyuki Yamamoto

Fumihiko Saito

Masatoshi Seto

Noriyuki Ohta

Masakazu Matsumoto

Keiji Araki

Hiroyuki Yoshida

Noriyuki Ota

Masashi Marubara

Akira Kageyama

Masayuki Kuroki

Tohru Shiraishi

Hidetoshi Kudo

A fuel spray and a tumble collide with each other from approximately opposite directions in a cavity formed in a piston head so that a combustible mixture stays around a spark plug for an extended period of time. An upper opening of the cavity is elongated to both the left and right sides of a cylinder axis. The distance between a ceiling of the combustion chamber and a bottom surface of the cavity is smaller on the right side of the cylinder axis than on the left side thereof and largest at least at a point where the cylinder axis crosses the bottom surface of the cavity, and a portion of the cavity to the left of the cylinder axis has a larger volumetric capacity than a portion of the cavity to the right of the cylinder axis, whereby a strong tumble is maintained up to a fuel injection point.

Direct-injection spark-ignition engine

During stratified-charge combustion operation of a direct-injection spark ignition engine, at the cylinder compression stroke, a tumble is generated which flows between a spark plug electrode and a piston crown surface toward an injector. A fuel is injected from the injector in correspondence with the cylinder ignition timing by controlling the penetration of fuel spray from the injector to correspond to the tumble flow rate so that the fuel spray may go against the tumble, become a flammable mixture at the cylinder ignition timing and stay near the spark plug electrode. In the late stage of the compression stroke, diffusion of the flammable mixture is suppressed with squishes. Thus, fuel spray behavior in the combustion chamber is controlled to allow suitable mixture stratification over a wide engine operating condition range. This improves combustion quality and extends a stratified-charge combustion zone thereby providing enhanced fuel economy and power output.

Direct-injection spark ignition engine

A direct injection engine in which an injector injects fuel toward a cavity formed in a top surface of a piston to produce a locally distributed mixture around a spark plug is constructed such that the direction of a fuel spray ejected from the injector is varied during a fuel injection period to properly spread the mixture and prevent its local overrichness. The direct injection engine is provided with means for generating a swirl, for example, so that the fuel spray from the injector is directed toward the spark plug when the pressure in a cylinder is low in a compression stroke, and the fuel spray is deflected by the swirl away from the direction of the spark plug as the pressure in a cylinder increases.

Direct injection engine

A direct injection engine provided with an injector at a peripheral portion of a combustion chamber to inject at least at a latter stage of a compression stroke in at least in a low engine load and low engine speed condition, wherein a distance from the tip end of the injector to an opposite end the combustion chamber is determined greater than a traveling distance of an injected fuel for a time period from a start of a fuel injection at the latter stage of the compression stroke to the ignition timing, wherein; an ignition plug is arranged that an ignition gap is disposed within an injection area of the injector; and, wherein a distance from the tip end of the injector to the ignition gap is determined smaller than said traveling distance of the injected fuel. An ignitability and combustion stability can be improved to thereby improve a fuel consumption efficiency.

Direct fuel injection engine

Growing community of inventors

Tokyo, Japan

Takehiko Yasuoka