JPS56162218A - System for supplying secondary air for engine - Google Patents

Abstract

PURPOSE: To permit the effective function of a three constituents catalyst for an internal-combustion engine by a method wherein secondary air in suction air series for two systems and the secondary air in exhaust series for one system are controlled altogether by the output of an exhaust sensor.

CONSTITUTION: Atmosphere pressure at a hole 18 located at slightly upstream from the fully closed position of a choke valve 4 upon idling of the engine acts on a diaphragm 15 through a pressure regulating valve 20 and closes a valve 12 for an EGR passage between the hole 7 of an exhaust pipe and the hole 10 of a suction air pipe 3 entirely to stop the EGR. The secondary air in the exhaust series is supplied by the pulsation of the exhaust gas from a passage 45, opened to atmosphere through a valve 39 provided in parallel with a lead valve 37, opening in the passage 12, and a chock valve 35, to the hole 7. On the other hand, a valve 58 between the hole 53 of the suction air pipe 3 and a hole 56 for releasing atmosphere, a negative pressure control valve 47, the valve 39 are controlled by a control device 51 operated by the output of an exhaust gas sensor 61 to control the secondary air in the exhaust system. Upon operation under a load heavier than a medium load, the EGR valve 12 is opened by the same mechanism to control the secondary air in the suction air series as well as a valve 58 in a secondary air pipeline 54 in the second suction air series by the valve 39, thus, the three constituents catalyst is functioned effectively.

COPYRIGHT: (C)1981,JPO&Japio