Abstract: A piston combustion chamber structure of an engine includes two or more independent combustion chambers separated from each other and dented on an upper portion of a piston head in axial and circumferential directions. Each of the two or more independent combustion chambers comprises an outer wall and a bottom surface. Independent combustion chambers adjacent to each other among the two or more independent combustion chambers are partitioned by a partition wall. The partition wall has a slant surface such that a squish flowing in the circumferential direction can be generated.

Abstract: A method of improving fuel efficiency and an apparatus for operating a vehicle that performs the method are provided. The apparatus includes a storing unit that stores control plans for a fuel injection system and an intake/exhaust system that optimize responsiveness of an engine for a plurality of driving modes. A catalyst temperature obtaining unit obtains a catalyst temperature and an operation period determining unit determines an operation period of an engine based on rpm of the engine and an amount of fuel consumption. A driving mode determining unit determines any one of the driving modes as a current driving mode based on the catalyst temperature, the operation period, and present time. Additionally, a controller is configured to access a control plan that corresponds to the current driving mode and operate the fuel injection system and the intake/exhaust system based on the control plan corresponding to the current driving mode.

Abstract: A method of improving fuel efficiency and an apparatus for operating a vehicle that performs the method are provided. The apparatus includes a storing unit that stores control plans for a fuel injection system and an intake/exhaust system that optimize responsiveness of an engine for a plurality of driving modes. A catalyst temperature obtaining unit obtains a catalyst temperature and an operation period determining unit determines an operation period of an engine based on rpm of the engine and an amount of fuel consumption. A driving mode determining unit determines any one of the driving modes as a current driving mode based on the catalyst temperature, the operation period, and present time. Additionally, a controller is configured to access a control plan that corresponds to the current driving mode and operate the fuel injection system and the intake/exhaust system based on the control plan corresponding to the current driving mode.