Abstract: An air injection system for an engine includes an exhaust flange formed in a cylinder head integrated with an exhaust manifold, wherein the exhaust manifold is coupled to the exhaust flange, an air injection nozzle provided on the cylinder head or the exhaust manifold, a valve configured to control air supplied to the air injection nozzle, and a controller configured to control the valve, wherein the controller is configured to control the valve and inject air through the air injection nozzle when an exhaust-gas temperature reaches a predetermined combustion temperature in an initial start stage of the engine.

Abstract: An accelerator sensor that is mounted on an engine block may be used to detect vibration of a compression ignition engine, and the detected vibration signal is analyzed to determine the combustion timing of the engine. A method for detecting combustion timing may include measuring a block vibration signal generated in a combustion process of an engine, setting up a frequency area that is to be analyzed in the block vibration to divide the frequency area into wavelet scales, executing continuous wavelet transformations of the divided wavelet scales to extract respective result values thereof and to calculate differences between former result values and latter result values, comparing the calculated difference value with a predetermined value to store crank angles of pertinent timing if the calculated difference values exceed the predetermined value, and averaging the stored crank angles to determine combustion timing in a case that all wavelet scales are processed.

Abstract: A combustion system for a vehicle may include a piston in which a first combustion recess is formed in an upper end surface thereof, and at least one second combustion recess is further formed at the bottom of the first combustion recess, a first intake port and a second intake port for supplying a cylinder with air, and a controller that differently controls amounts of recirculation exhaust gas being supplied to the first intake port and the second intake port.

Abstract: An accelerator sensor that is mounted on an engine block may be used to detect vibration of a compression ignition engine, and the detected vibration signal is analyzed to determine the combustion timing of the engine. A method for detecting combustion timing may include measuring a block vibration signal generated in a combustion process of an engine, setting up a frequency area that is to be analyzed in the block vibration to divide the frequency area into wavelet scales, executing continuous wavelet transformations of the divided wavelet scales to extract respective result values thereof and to calculate differences between former result values and latter result values, comparing the calculated difference value with a predetermined value to store crank angles of pertinent timing if the calculated difference values exceed the predetermined value, and averaging the stored crank angles to determine combustion timing in a case that all wavelet scales are processed.

Abstract: A combustion system for a vehicle may include a piston in which a first combustion recess is formed in an upper end surface thereof, and at least one second combustion recess is further formed at the bottom of the first combustion recess, a first intake port and a second intake port for supplying a cylinder with air, and a controller that differently controls amounts of recirculation exhaust gas being supplied to the first intake port and the second intake port.