Abstract: In an engine which includes an oxidation catalyst and an SCR catalyst in an exhaust passage, a first flow regulating control in which a control valve is controlled so as to decrease a flow rate of an exhaust gas which passes through the oxidation catalyst and the SCR catalyst is performed in a case where the oxidation catalyst is in a low temperature state at the time of performing deceleration fuel cut, and a second flow regulating control in which the control valve is controlled so as to increase the flow rate of the exhaust gas which passes through the oxidation catalyst and the SCR catalyst is performed in a case where the oxidation catalyst is in a temperature state higher than the low temperature state and the SCR catalyst is in a low temperature state at the time of performing the deceleration fuel cut.

Abstract: In an engine which includes an oxidation catalyst and an SCR catalyst in an exhaust passage, a first flow regulating control in which a control valve is controlled so as to decrease a flow rate of an exhaust gas which passes through the oxidation catalyst and the SCR catalyst is performed in a case where the oxidation catalyst is in a low temperature state at the time of performing deceleration fuel cut, and a second flow regulating control in which the control valve is controlled so as to increase the flow rate of the exhaust gas which passes through the oxidation catalyst and the SCR catalyst is performed in a case where the oxidation catalyst is in a temperature state higher than the low temperature state and the SCR catalyst is in a low temperature state at the time of performing the deceleration fuel cut.

Abstract: An exhaust emission control system, which comprises control means 8 operable, in response to satisfaction of a given stop condition, to automatically stop an engine, and subsequently, in response to satisfaction of a given restart condition, to automatically restart the automatically stopped engine, a flow passage 6 adapted for an aqueous urea solution for reducing nitrogen oxides contained in exhaust gas of the engine, and supply/recovery means 7 adapted to drive a pump 10 to supply an aqueous urea solution to the flow passage and recover an aqueous urea solution from the flow passage. The control means is operable, when the engine is forcibly stopped by turning off an ignition switch, to instruct the supply/recovery means 7 to recover an aqueous urea solution from the flow passage 6, and, when automatically stopping the engine in response to satisfaction of the given stop condition, to prohibit the supply/recovery means 7 from recovering an aqueous urea solution from the flow passage 6.

Abstract: An exhaust emission control system, which comprises control means 8 operable, in response to satisfaction of a given stop condition, to automatically stop an engine, and subsequently, in response to satisfaction of a given restart condition, to automatically restart the automatically stopped engine, a flow passage 6 adapted for an aqueous urea solution for reducing nitrogen oxides contained in exhaust gas of the engine, and supply/recovery means 7 adapted to drive a pump 10 to supply an aqueous urea solution to the flow passage and recover an aqueous urea solution from the flow passage. The control means is operable, when the engine is forcibly stopped by turning off an ignition switch, to instruct the supply/recovery means 7 to recover an aqueous urea solution from the flow passage 6, and, when automatically stopping the engine in response to satisfaction of the given stop condition, to prohibit the supply/recovery means 7 from recovering an aqueous urea solution from the flow passage 6.

Abstract: A soot sensor includes a center electrode extending in an axial direction and a cylindrical insulator from which a leading end of the center electrode protrudes. The insulator is provided around a periphery of the center electrode and includes a heating element. The soot sensor also includes a sealing member sealing a gap between the insulator and the center electrode.

Abstract: A soot sensor includes an insulator having a through-hole and a center electrode provided in the through-hole of the insulator so that a leading end of the center electrode protrudes from a leading end of the insulator and faces a discharge gap. A heating member is embedded in the insulator, and the distance between the heating member and the leading end of the center electrode is at least 10 mm.