Hyundai Motor Company

Kia Motors Corporation

Pil Sung Jang

Wootae Kim

Han Sang Kim

Bonghoon Han

A method for manufacturing a piston can prevent casting defects such as oxide inclusions or shrinkage cavities on the surface of a combustion chamber over a piston head after casting. The method includes casting a head top having a bowl by pouring a first molten metallic material into a first mold with a bonding portion of the head top to be formed at an upper portion in the first mold and a first riser on the bonding portion of the head top, casting the body by pouring a second molten metallic material into a second mold, with a bonding portion of the body to be formed at an upper portion in the second mold and a second riser on the bonding portion of the body, removing the risers from the head top and the body, and integrally bonding the head top and the body to form the piston.

Method for manufacturing piston of automobile engine

Disclosed is a variable compression ratio device which changes a top dead center of a piston provided in an engine depending on a driving state of the engine. The variable compression ratio device may include: a lower piston reciprocally movable in a cylinder of the engine and connected with a connecting rod to rotate a crankshaft, an operation chamber, an upper piston disposed above the lower piston and partially inserted into the operation chamber, a push plate dividing the operation chamber into upper and lower spaces, a hydraulic pressure chamber which is the lower space, an elastic member provided in the upper space to push the push plate downward, a hydraulic pressure supply unit selectively supplying hydraulic pressure to the hydraulic pressure chamber, and a hydraulic pressure supply pathway connecting the hydraulic pressure supply unit and the hydraulic pressure chamber for supplying the hydraulic pressure.

Variable compression ratio device

A gasoline direct injection engine that has an injector directly injecting fuel into a combustion chamber, a spark plug, an intake valve, and an exhaust valve and generates power by reciprocating a piston in a cylinder, may include a first cavity formed on a piston head of the piston to return at least some flow of the fuel injected from the injector to the spark plug, a protrusion protruding and off-set from the first cavity toward the exhaust valve, and a second cavity formed from the protrusion to the exhaust valve at a smaller height than the first cavity.

Growing community of inventors

Seoul, South Korea

Pil Sung Jang