Patent ID: 6431158
Filing Date: 2002-08-13
Classification: F02M

Abstract:
An internal combustion engine exhaust emission control system comprising:a flow path for conveying exhaust gas from an exhaust system of the engine to an intake system of the engine and comprising a side wall bounding a portion of the flow path, a valve for selectively restricting the flow path, a pressure sensor having a pressure sensing port, and a pressure sensing passage communicating the pressure sensing port to the flow path, wherein the pressure sensing passage comprises a tube having an end portion passing through a through-hole in the side wall of the flow path to dispose an open free end of the tube within the flow path in spaced relation to the side wall, and a device which is disposed downstream of the open free end of the tube, through which flow through the flow path is constrained to pass, and which creates a pressure drop in the flow path that bears a known relationship to flow rate through the device for correlating rate of flow through the device to pressure drop across the device, wherein the device comprises a nozzle.