Abstract: An aspect of the invention provides a method for operating a workable homogeneous charge compressed ignition engine in which a compression ignition operation is performed by spark ignition to shorten a load input time and a load cutoff time. In the homogeneous charge compressed ignition engine operating method, a mixture gas is burned by compression ignition in a combustion chamber, and fuel and air are previously mixed to produce the mixture gas. The homogeneous charge compressed ignition engine includes a spark ignition device 53 which performs spark ignition to the mixture gas. A temperature controller 35 substantially keeps an intake air temperature of the mixture gas constant. A spark ignition operation, a spark-assist compression ignition operation in which spark ignition is supplementarily used, and a non-spark compression ignition operation in which the spark ignition is not used are switched according to magnitude of a load.

Abstract: A method is provided for operating a homogeneous charge compressed ignition engine in which a mixture gas is burned by compression ignition in a combustion chamber of a cylinder, fuel and air being previously mixed to produce the mixture gas. The homogeneous charge compressed ignition engine includes an ignition plug, which performs spark ignition to the mixture gas. An advance-angle limit and a delay-angle limit of spark ignition timing are set. The compression ignition of the mixture gas is able to be induced at the spark ignition timing. The spark ignition is supplementarily performed to the mixture gas according to an operating condition between the advance-angle limit and the delay-angle limit.

Abstract: An aspect of the invention provides a method for operating a workable homogeneous charge compressed ignition engine in which a compression ignition operation is performed by spark ignition to shorten a load input time and a load cutoff time. In the homogeneous charge compressed ignition engine operating method, a mixture gas is burned by compression ignition in a combustion chamber, and fuel and air are previously mixed to produce the mixture gas. The homogeneous charge compressed ignition engine includes a spark ignition device 53 which performs spark ignition to the mixture gas. A temperature controller 35 substantially keeps an intake air temperature of the mixture gas constant. A spark ignition operation, a spark-assist compression ignition operation in which spark ignition is supplementarily used, and a non-spark compression ignition operation in which the spark ignition is not used are switched according to magnitude of a load.

Abstract: Compression ignition is induced by spark ignition to realize stable ignition, thereby expanding an operation range where the compression ignition is operable, even in an operating condition in which the compression ignition is hardly performed. Improvements of cycle efficiency and thermal efficiency and restraint of air-pollution substance emission can be realized by properly adjusting compression ignition timing in a cylinder.

Abstract: A fuel feed device of a gas engine of non-supercheged type for feeding air and fuel to an intake port without mixing by amixer, wherein fuel gas is fed into the intake port by utilizing a negative pressure generated in the intake port in an intake stroke.

Abstract: In an internal combustion engine (100) provided with an NOx absorbing reduction catalyst (2) in an exhaust gas passage (1), there are arranged: an oxygen sensor (3) which is mounted downstream of the NOx absorbing reduction catalyst (2) in the exhaust gas passage (1); and a determination means for determining a condition of degradation of the NOx absorbing reduction catalyst (2) on the basis of a time length, during which a voltage value, having a small amount of variation before the voltage value outputted from the oxygen sensor (3) is recorded as a maximum value when executing a rich spike, is recorded.

Abstract: A fuel feed device of a gas engine of non-supercheged type for feeding air and fuel to an intake port without mixing by amixer, wherein fuel gas is fed into the intake port by utilizing a negative pressure generated in the intake port in an intake stroke.

Abstract: In an internal combustion engine utilizing an exhaust gas recirculation, an exhaust gas recirculation rate is set to a minimum or zero at a small engine load.

Abstract: In an internal combustion engine (100) provided with an NOX absorbing reduction catalyst (2) in an exhaust gas passage (1), there are arranged: an oxygen sensor (3) which is mounted downstream of the NOX absorbing reduction catalyst (2) in the exhaust gas passage (1); and a determination means for determining a condition of degradation of the NOX absorbing reduction catalyst (2) on the basis of a time length, during which a voltage value, having a small amount of variation before the voltage value outputted from the oxygen sensor (3) is recorded as a maximum value when executing a rich spike, is recorded.

Abstract: A method for controlling knocking of an internal combustion engine in which a knocking signal and a combustion signal are formed by directing vibrations detected by a vibration sensor through a primary filter circuit including a combustion filter circuit and a knocking filter circuit. The combustion filter circuit and knocking filter circuit each include a time gate and a filter. A ratio of a representative value of the knocking signal to a representative value of the combustion signal is obtained and used to decide whether knocking is occurring. The output voltage of control signals generated based on the decision that knocking is occurring may be varied as a function of the strength of the knocking and/or the frequency of the knocking.