Electronic Throttle Control: Description

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Torque based Electronic Throttle Control (ETC) is a strategy that delivers a transmission output shaft torque (via throttle angle) based on driver demand (pedal position). It utilizes the Visteon Gen II electronic throttle body (replaces throttle cable). See Figure. Torque based ETC strategy was developed mainly to improve fuel economy. This is possible by not coupling the throttle angle to pedal position, which enables various fuel economy schemes and technologies.

Torque based ETC enables aggressive automatic transmission shift schedules (earlier upshifts and later downshifts). This is possible by adjusting the throttle angle to achieve the same wheel torque during shifts. In other words, the engine shifts can result is an engine lugging condition (low RPM and low manifold vacuum) while still delivering the same torque requested by the driver. It should be noted that the ETC system includes a wrench light on the instrument cluster that illuminates when a fault is detected. Faults are also accompanied by DTCS and the "Check Engine Soon" light.

It also enables many fuel economy/emission improvement technologies such as:

VCT (deliver same torque during transitions)
Continuously Varying Transmission (CVT)
Hybrid Electric Vehicle (HEV)

Torque based ECT also results is a less intrusive vehicle and engine speed limiting, along with smoother traction control. Other generic benefits of ETC are:

Eliminate cruise control actuators
Eliminate ISC Bypass actuator
Better airflow range
Packaging (no cable)