GE Measurement & Control Solutions (MCS)' Thermometric product line plays a vital role in the measurement, control, and protection of automobiles, medical devices, telecommunications systems, fluorescent lights, domestic appliances, and countless other applications. GE Measurement & Control Solutions (MCS) recently acquired Thermometrics, a leader for nearly 60 years in the design and manufacture of high quality thermistors and varistors.
GE Measurement & Control Solutions (MCS) offers a wide array of thermistors and industrial temperature and humidity sensors through their Thermometric product lines.
Thermometrics Corporation has built thermistor probe capable of measuring temperatures up to 1000°C. This sensor can be a direct replacement for thermocouple and rtd sensors currently being used to monito exhaust gas temperatures.
The types of thermistors found in a vehicle exhaust environment will typically produce a negative temperature coefficient (NTC), meaning the resistance will decrease with increasing temperature. Thermistors offer a high sensitivity over a smaller range in temperature than either thermocouples or RTDs. At 0°C the resistance can be over 100,000 Ω,at 200°C 200 to 500 :, and at 800°C 50:. Thus,thermistors can achieve very high sensitivities over a particular range of temperatures. However, achieving nearly the same accuracy over a large range in temperatures is not possible (unless several pull up resistors are used) due to the highly nonlinear characteristic response.
Exhaust gas temperature is a measure of heat in the cylinder during combustion, and is most commonly measured close to the head. Since all metals melt, deform, or undergo transformation under excessive temperatures for that particular metal, it is easy to have too high of EGT and cause damage to engine/turbo components. Thus a tuner must measure the EGTs and keep them in check or suffer the consequences. High EGTs also contribute to knock. You cannot tune your car by EGTs alone, and you should not tune your car without measuring the EGTs.