What is the purpose of the spark plug in an internal combustion engine?

The spark plug is a crucial component in an internal combustion engine, serving the primary purpose of igniting the gas/air mixture within the combustion chamber. When the engine is operating, the spark plug generates a spark at the precisely timed moment, creating the high temperature necessary to ignite the compressed mixture of fuel and air. This ignition initiates the combustion process, which ultimately drives the piston down and generates power for the vehicle.

Understanding the function of the spark plug highlights its importance in ensuring efficient engine operation. Without a functioning spark plug, the combustion process would be compromised, leading to poor engine performance or failure to start. The other options, while important aspects of engine operation, do not accurately reflect the spark plug's role—lubrication pertains to oil systems, measuring fuel efficiency involves sensors and computers, and regulating engine temperature relates to the cooling system.