Patent ID: 7481915
Filing Date: 2009-01-27
Classification: F01N,F02D,Y02T

Abstract:
1. A system for determining a temperature of exhaust gases from an engine, comprising an exhaust gas sensor having an electric heating coil, said sensor communicating with the exhaust gases; an electrical circuit for generating a signal indicative of the resistance of said heating coil when said coil is de-energized; a controller receiving said signal and calculating said temperature of said exhaust gases based on said signal, where the controller generates a duty cycle to successively energize and de-energize said coil, and where the controller calculates said temperature during a plurality of successive de-energized periods of the duty cycle, the heater being operated to heat the sensor when it is below its desired operating temperature; and a switching circuit for coupling the electrical circuit to the electric heating coil during said de-energizing of the coil, and uncoupling the electric circuit from the electric heating coil during said energizing of the coil.