Abstract: A variable valve timing controller includes an intake-valve and an exhaust-valve. When the engine is started, the intake-valve and the exhaust-valve are operated in a first mode in which the exhaust-valve is closed before top dead center and then the intake-valve is opened. When a first predetermined condition is met, the intake-valve and the exhaust-valve are operated in a second mode in which the opening time of the intake-valve in the first mode is advanced before top dead center.

Abstract: There is provided a valve timing control apparatus for an engine, which comprises a variable valve mechanism capable of varying at least one of an opening timing of intake valves and a closing timing of exhaust valves in an engine, an elapsed time detecting device that detects a time period elapsed after cold-starting of the engine, and a timing control device that controls the variable valve mechanism. The timing control device provides advance angle control such that the opening timing of the intake valves and/or the closing timing of the exhaust valves is advanced to be earlier than an exhaust top dead center until the elapsed time period detected by the elapsed time detecting device has reached a predetermined time period.

Abstract: There is provided a combustion chamber structure in an internal combustion engine in which, at a peripheral portion of a combustion chamber, a gap between a cylinder head lower face and a piston upper face is small in intake-to-intake and exhaust-to-exhaust zones and gradually increases toward an intake-to-exhaust zone. According to such design, the mixture in the peripheral portion of the combustion chamber can smoothly flow from the intake-to-intake and exhaust-to-exhaust zones to the intake-to-exhaust zone along the peripheral face of the cylinder. The flow of air-fuel mixture from the intake-to-intake zone collides at the center of the intake-to-exhaust zone with the flow of mixture from the exhaust-to-exhaust zone, and the combined flow goes over a conical tapered portion in the upper face of the piston and vigorously enters a central recessed portion thereof. Therefore, it is possible to satisfactorily mix an air-fuel mixture with a simplified configuration.

Abstract: There is provided a valve timing control apparatus for an engine, which comprises a variable valve mechanism capable of varying at least one of an opening timing of intake valves and a closing timing of exhaust valves in an engine, an elapsed time detecting device that detects a time period elapsed after cold-starting of the engine, and a timing control device that controls the variable valve mechanism. The timing control device provides advance angle control such that the opening timing of the intake valves and/or the closing timing of the exhaust valves is advanced to be earlier than an exhaust top dead center until the elapsed time period detected by the elapsed time detecting device has reached a predetermined time period.

Abstract: There is provided a combustion chamber structure in an internal combustion engine in which, at a peripheral portion of a combustion chamber, a gap between a cylinder head lower face and a piston upper face is small in intake-to-intake and exhaust-to-exhaust zones and gradually increases toward an intake-to-exhaust zone. According to such design, the mixture in the peripheral portion of the combustion chamber can smoothly flow from the intake-to-intake and exhaust-to-exhaust zones to the intake-to-exhaust zone along the peripheral face of the cylinder. The flow of air-fuel mixture from the intake-to-intake zone collides at the center of the intake-to-exhaust zone with the flow of mixture from the exhaust-to-exhaust zone, and the combined flow goes over a conical tapered portion in the upper face of the piston and vigorously enters a central recessed portion thereof. Therefore, it is possible to satisfactorily mix an air-fuel mixture with a simplified configuration.

Abstract: A variable valve timing controller includes an intake-valve and an exhaust-valve. When the engine is started, the intake-valve and the exhaust-valve are operated in a first mode in which the exhaust-valve is closed before top dead center and then the intake-valve is opened. And if a first predetermined condition is met, the intake-valve and the exhaust-valve are operated in a second mode in which the opening time of the intake-valve in the first mode is advanced before top dead center.

Abstract: A startup control apparatus of an internal combustion engine is provided wherein when an engine starting capability determining device determines that the engine can be successfully started even if driving of part of the fuel injector valves is stopped during engine startup, the fuel injection is stopped with respect to the part of the fuel injector valves. With this arrangement, overshoot of the engine speed that would otherwise occur upon the start of the engine can be suppressed, and unburned fuel components can be prevented from being discharged, thus assuring improved exhaust gas characteristics and improved fuel efficiency.