All parts of the engine temperature measurement system are made of which materials?

All parts of the engine temperature measurement system are made of which materials?

• A. Copper And Brass
• B. Chromel And Alumel
• C. Iron And Nickel
• D. Aluminum And Magnesium

Answer: (B)

Engine temperature is read with a thermocouple, which relies on two dissimilar metals joined at the sensing tip to generate a voltage that varies with temperature. The standard pair used for the engine temperature system is Chromel and Alumel, which form a Type K thermocouple. Using these two alloys for the sensing element and all leads keeps the thermoelectric response consistent along the entire circuit, so the voltage accurately reflects temperature without extra errors from different metals. Chromel provides good high‑temperature stability and oxidation resistance, while Alumel completes the pair to give a reliable, broad temperature range signal. Using any other metal combination would change the voltage vs. temperature characteristics and require a different calibration, making Chromel and Alumel the best fit for the whole system.

Engine temperature is read with a thermocouple, which relies on two dissimilar metals joined at the sensing tip to generate a voltage that varies with temperature. The standard pair used for the engine temperature system is Chromel and Alumel, which form a Type K thermocouple. Using these two alloys for the sensing element and all leads keeps the thermoelectric response consistent along the entire circuit, so the voltage accurately reflects temperature without extra errors from different metals. Chromel provides good high‑temperature stability and oxidation resistance, while Alumel completes the pair to give a reliable, broad temperature range signal. Using any other metal combination would change the voltage vs. temperature characteristics and require a different calibration, making Chromel and Alumel the best fit for the whole system.