Precision Position-Sensors in Automotive Applications

The use of microprocessors in automotive electronics systems such as Electronic Fuel Injection (EFI) and Electronic Fuel Management (EFM) has created a need for a variety of precision position-sensors capable of reliable performance in underhood environments. This paper describes the basics of precision potentiometers and switches which have been adapted for these and other specialized engine applications.

A brief description introduces the precision potentiometer as a position-sensor, and details the differences among the more common types of potentiometers. The fundamental low cost position-sensor concept is elaborated upon with a discussion of some of the special materials and techniques used to develop units for automotive applications. Among the special problems discussed are requirements of long life at high temperature, high vibration environment, and stringent performance accuracy.

Also discussed are typical applications in Exhaust Gas Recirculation, Electronic Fuel Injection, and Throttle Position Sensing.