Abstract: A controller for an exhaust purifier performs idle-up to increase the idle speed of a diesel engine when an intake air amount, which is based on the atmospheric pressure and the engine speed, is less than a reference air amount of when a throttle valve is completely open and an EGR valve is completely closed during the regeneration of the filter. The controller performs idle-up by increasing the amount of fuel injected from the fuel injection valves of the diesel engine.

Abstract: A controller for an exhaust purifier performs idle-up to increase the idle speed of a diesel engine when an intake air amount, which is based on the atmospheric pressure and the engine speed, is less than a reference air amount of when a throttle valve is completely open and an EGR valve is completely closed during the regeneration of the filter. The controller performs idle-up by increasing the amount of fuel injected from the fuel injection valves of the diesel engine.

Abstract: An exhaust gas purifying device according to the present invention has an exhaust emission control catalyst provided in an exhaust passage of an internal combustion engine, a reducing agent adding unit provided in the exhaust passage at a position upstream of the exhaust emission control catalyst for adding a reducing agent, a control unit for controlling the reducing agent adding unit, and an air-fuel ratio estimating unit for estimating an air-fuel ratio prior to addition of the reducing agent. The control unit performs control such that addition of the reducing agent by the reducing agent adding unit is stopped when the air-fuel ratio estimated by the air-fuel ratio estimating unit reaches a stop reference value. When the air-fuel ratio is leaner than the stop reference value, the reduction efficiency of the exhaust emission control catalyst is low, so fuel serving as the reducing agent is wasted.

Abstract: An internal combustion is capable of switching, during engine operation, between a low-temperature combustion state in which an intake air with a high EGR rate is burned to operate the engine, and a normal combustion state in which an intake air with a low EGR rate is burned to operate the engine. In the internal combustion engine, a pilot injection is executed in addition to a main fuel injection, and furthermore the execution of the pilot injection is restricted during the engine operation with a combustion state switched to the low-temperature combustion state.

Abstract: An internal combustion is capable of switching, during engine operation, between a low-temperature combustion state in which an intake air with a high EGR rate is burned to operate the engine, and a normal combustion state in which an intake air with a low EGR rate is burned to operate the engine. In the internal combustion engine, a pilot injection is executed in addition to a main fuel injection, and furthermore the execution of the pilot injection is restricted during the engine operation with a combustion state switched to the low-temperature combustion state.

Abstract: Disclosed are an improved method of refining steel and an apparatus for practicing the method.The refining method comprises, basically, carrying out the refining, particularly, decarburization, while stirring molten steel in the refining furnace by injecting gas thereinto, while supplying heat with a burner installed at the top of the furnace to the molten steel. According to this method, it is possible to start at an initial carbon content of the moltend steel lower than that of known AOD process, and complete the refining in a curtailed period of time and with a decreased oxidation loss of Cr. Thus, damage of refractory materials of the furnace is reduced, and the amount of Si necessary for reducing Cr-oxides in the latter stage of the refining is also reduced.Oxygen for the decarburization is supplied usually in the form of gas, but can be supplied from a solid oxygen source.