How can the operating temperature of spark plugs be measured?

The correct method to measure the operating temperature of spark plugs is by using a thermocouple. A thermocouple operates by generating a small voltage when there is a temperature difference between its two junctions. This voltage can then be interpreted to give an accurate reading of the spark plug temperature based on established calibration curves.

In the context of engine performance, accurately measuring the temperature of spark plugs is critical, as it impacts ignition, combustion efficiency, and overall engine operation. High temperatures can indicate issues such as pre-ignition or detonation, while low temperatures may suggest poor combustion.

Other tools, like a voltmeter, pressure gauge, or current meter, are not suitable for measuring temperature directly. A voltmeter measures electrical potential and cannot provide temperature readings, while a pressure gauge assesses the pressure within systems, and a current meter measures electrical current. These tools may provide valuable information about engine systems but do not give insights into the temperature of the spark plugs.