Valve operation verification system for verifying valve operation of valve disposed in hot gas flow passage

摘要

A valve operation verifying system for making verification of valve operation of an EGR valve of a type having a diaphragm elastically deformable according to operating conditions of an engine to admit controlled amounts of exhaust gas that is recirculated into an intake air stream which verifies, on a basis of gas pressure in an EGR passage, whether the diaphragm remains elastically deformable as specified and whether a pressure sensor remains free from freezing, and executes the verification of valve operation of the EGR valve on a basis of a change in the gas pressure in the EGR passage when the EGR valve opens and when it closes, and when the temperature of ambient air is lower than a critical point, verifying that the diaphragm remains elastically deformable as specified and that said pressure sensor is free from freezing.