VAPOR PURGE SYSTEM HAVING VENTURI HOSE-OFF DETECTION CAPABILITY

An vapor purge system for a turbocharged internal combustion engine having an evaporative emissions turbo purge valve incorporating a venturi vacuum generator and a hose-off detection function. The turbo purge valve includes a pressure sensor, and a low restriction check valve which is integrated into the outlet port of the venturi vacuum generator. The pressure sensor is capable of detecting the small pressure drop (i.e., vacuum) generated at the air inlet tube or air box during naturally aspirated conditions. The check valve closes the venturi vacuum generator on the purge side during naturally aspirated conditions, allowing fluid communication to the air intake system through one port only, and the detection of the vacuum during these conditions. If a hose becomes detached, either at the outlet port of the venturi vacuum generator or at the air box, the small vacuum is not detected, and the ECU then diagnoses the hose-off condition.