Abstract: An apparatus is provided which includes an internal combustion engine of a lean-burn type, an NOx catalyst disposed in an exhaust passage of the engine so as to remove nitrogen oxides contained in exhaust gas emitted from the engine, and a variable valve control system capable of changing at least one of the opening and closing timing and a lift of the intake valve and/or the exhaust valve for each cylinder of the engine. The variable valve control system is controlled so that the exhaust gas to which the NOx catalyst is exposed is controlled so as to be suitable for removing a selected gaseous component from the NOx catalyst when the selected gaseous component should be removed. A method of purifying an exhaust gas emitted from the above engine is also provided.

Abstract: A switching power supply comprises a transformer 3, a switching circuit 1, an output rectifier circuit, an output smoothing circuit, and a snubber circuit. A snubber capacitor 17 has one terminal connected to the one terminal of a snubber diode 19. The other end of the snubber capacitor is led to an output winding 4 of the transformer, while the other terminal of the snubber diode is led to the other of the electrode of an output rectifier diode 7. A snubber inductor 23 has one end connected to the connecting point of the snubber capacitor and the snubber diode, and the other end is. connected to the input side of the output smoothing circuit. The polarity of the diode is arranged to establish a charging loop circulating through the snubber diode, the snubber capacitor and the output winding of the transformer, so as to provide a reduced loss, in a cycle in which the voltage appearing at the output winding of the transformer is the reverse direction to the output rectifier diode.

Abstract: An internal combustion engine having an electromagnetic valve driving mechanism adjusts an amount of magnetizing current to be applied to the electromagnetic valve driving mechanism in accordance with a temperature or viscosity of a lubricant used in the electromagnetic valve driving mechanism. Accordingly, intake and exhaust valves can be driven with an electromagnetic force corresponding to a viscosity of the lubricant. Therefore, changes in opening-and-closing operation speeds of the intake and exhaust valves resulting from a temperature or viscosity of the lubricant that is supplied to a sliding portion of the electromagnetic valve driving mechanism can be reduced.

Abstract: An internal combustion engine includes two intake side solenoid driving valve mechanisms for opening and closing intake valves by cooperation of an electromagnetic coil and a spring, and/or two exhaust side solenoid driving valve mechanisms for opening and closing exhaust valves provided on each cylinder. A controller commands a driving circuit to cause the valve-opening timing of the exhaust valves or the intake valves to be different.

Abstract: An internal combustion engine having an electromagnetic valve driving mechanism adjusts an amount of magnetizing current to be applied to the electromagnetic valve driving mechanism in accordance with a temperature or viscosity of a lubricant used in the electromagnetic valve driving mechanism. Accordingly, intake and exhaust valves can be driven with an electromagnetic force corresponding to a viscosity of the lubricant. Therefore, changes in opening-and-closing operation speeds of the intake and exhaust valves resulting from a temperature or viscosity of the lubricant that is supplied to a sliding portion of the electromagnetic valve driving mechanism can be reduced.

Abstract: An apparatus is provided which includes an internal combustion engine of a lean-burn type, an NOx catalyst disposed in an exhaust passage of the engine so as to remove nitrogen oxides contained in exhaust gas emitted from the engine, and a variable valve control system capable of changing the opening and closing timing and/or a lift of the intake valve and/or the exhaust valve for each cylinder of the engine. The variable valve control system is controlled so that the exhaust gas to which the NOx catalyst is exposed is controlled so as to be suitable for removing a selected gaseous component from the NOx catalyst when the selected gaseous component should be removed. A method of purifying an exhaust gas emitted from the above engine is also provided.

Abstract: An internal combustion engine includes two intake side solenoid driving valve mechanisms for opening and closing intake valves by cooperation of an electromagnetic coil and a spring, and/or two exhaust side solenoid driving valve mechanisms for opening and closing exhaust valves provided on each cylinder. A controller commands a driving circuit to cause the valve-opening timing of the exhaust valves or the intake valves to be different.