Intake port pressure control apparatus for engine induction system.

摘要

An intake port pressure control apparatus (20) comprises an intake passage (32) leading to a cylinder (22) in an engine, and a check valve (34) in the intake passage to allow fluid flow toward the cylinder and obstruct fluid back-flow in the reverse direction. A bypass port (38) is located on the intake passage so that the bypass port communicates with a trapped volume (36) defined by the portion of the intake passage between the check valve and intake valve. The intake port pressure control apparatus further comprises a control valve means (54) having an outlet passage (55,58), a secondary passage (56,59), and an actuating means (57) enabling communication between the outlet passage and secondary passage. The actuating means further enables active adjustment of the flow area of the flowpath between the secondary passage and outlet passage throughout a range of engine operating conditions. The outlet passage is connected to the bypass port, and the secondary passage is connected to a secondary air source. The control valve means enables a controlled air flow from the secondary air source into the trapped volume when the intake valve is closed.