Traditional engine fuel control systems use a mechanical linkage to connect the accelerator pedal to the throttle valve. Engine idle speed is then controlled by a mechanical system that manipulates the pedal position according to engine load.
Since the mid-1970's electronic throttle control or “drive-by-wire” systems have been developed. Electronic throttle control systems replace the mechanical linkage between the accelerator pedal and the throttle valve with an electronic linkage. These types of systems have become increasingly common on modern automobiles.
Generally, at least one sensor is typically placed at the base of the accelerator pedal and its position is communicated to the engine controller. At the engine, a throttle position sensor and an electronically controlled motor then regulate the throttle to maintain a precise engine speed through a feedback system between the throttle position sensor and the electronically controlled motor. An example of an electronic throttle control system can be found with reference to U.S. Pat. No. 6,289,874 to Keefover, the entire specification of which is incorporated herein by reference.
In conventional electronic throttle control systems, the various components of the throttle position sensor stator and connector assembly are mounted to the casting. The connector assembly is also connected to the motor. Thus, the throttle position sensor stator and the connector assembly move simultaneously during assembly and thermal expansion, thus possibly allowing one or both of them to become misaligned, which could potentially affect performance of the electronic throttle control system.