| 摘要 |
<p>PURPOSE:To reduce harmful gas and the malodor of exhaust gas discharged outside by prompting temperature rise of catalyzer and effective oxidation of the catalyzer during starting or idling operation of an engine. CONSTITUTION:An inlet pipe 60, in which a first throttle valve 66 is arranged, is arranged upstream from an engine 50, and an exhaust pipe 70 to be connected to an emission control device 80 is connected downstream the engine 50. The first throttle valve 66 is closed by a closing signal from a controller 90 when the running condition requires throttling of suction and exhaust as the rotational speed or load of the engine 50 is low, and is opened for a short time by a opening signal from the controller 90 when temperature of the catalyzer in the emission control device 80 has reached the set (activating) temperature during a closed state of the first throttle valve 66. Thus, temperature rise of exhaust gas and activation of the catalyzer are promoted by continuing the closing and opening motion of this valve 66 until the running condition of the engine is satisfied.</p> |
