John P Early

US Patent:

45024448, Mar 5, 1985

Filed:

Jul 19, 1983

Appl. No.:

6/515695

Inventors:

John T. Rubbo - South Amboy NJ
Kenneth R. Burns - Westfield NJ
Ronald M. Heck - Frenchtown NJ
John J. Early - Perth Amboy NJ

Assignee:

Engelhard Corporation - Iselin NJ

International Classification:

F02B 300

US Classification:

123440

Abstract:

A system for the control of the air-fuel ratio in an internal combustion engine incorporates an electronic control unit, a sensor of exhaust emissions and a valve for metering fuel with air to control the air-fuel ratio. The electronic control unit provides for the comparison of successive measurements of the sensor output voltage under conditions wherein the fuel valve is being operated for ever increasing richness or leaness until such time as the differential measurement drops below a predetermined amount. An offset voltage is then subtracted from or added to this voltage to calculate an operating set point voltage. Thereby, the system's accuracy is maintained through the compensation for changed sensor characteristics with aging.