Most of us might be coming across the term the first time ‘Throttle Position Sensor’. So, what is it? And what it does? In Simple Words, Throttle Position Sensor aka TPS is a kind of sensor that monitors and controls the throttle position of the vehicle. TPS is usually fixed to the shaft/spindle to promptly monitor the throttle position. Upgraded versions of TPS such as CTPS (Closed Throttle Position Sensor) which indicates complete closing of the throttle are also applied.
Other than TPS, Throttle position is also controlled by ECU’s (Engine Control Units). ECU’s employ ETC (Electronic Control Throttle) or drive by wire process. In Such Cases, TPS will be utilized in the feedback loop in enabling the control. Aside TPS, there are Accelerator Pedal sensors (APS) which often incorporate WOT (Wide Open Throttle) sensor. APS are generally employed by the above mentioned ECU’s (either ETC/drive by wire) and WOT sensor are primarily employed for kick-down on auto transmissions.
FRAMEWORK AND WORKING
Multi-finger Metal Rake or Brush are utilized by Potentiometric type sensors wherein the Metal Brush/Rake gets in contact with the resistive strip; in unison, the butterfly regulator is rotated from minor position of mechanical stop to WOT. The difference in resistance created due to the regulator’s rotation becomes ECU’s primary info.
Presently, Non-Contact TPS are used which employs Inductive sensor, Hall Effect sensors or Magnetoresistive techniques. These technologies either use the Magnet or the Inductive Loop as the active part which is erected atop the butterfly regulator Shaft/Spindle. Moreover, the circuit board processing the sensor and its signals is installed inside the ETC Gearbox and is static.
A change in magnetic field occurs in the sensor when the magnet/inductive loop on the shaft turn. The resulting change generates a change in electric charge (Voltage) becoming ECU’s input. Basically, a rare earth magnet (two pole) is employed for TPS due its ability to withstand high temperatures. The employed magnets could be either a Segment or a Ring or a Rectangular or a diametrical one. Non-functioning TPS could be detected by the glow of CHECK ENGINE light.