What is the function of the camshaft in a diesel engine?

You chose the correct answer: the camshaft controls the valves in the engine. In a diesel engine, the camshaft is a rotating shaft with specially shaped lobes (cams) that open and close the intake and exhaust valves at the right times during the engine cycle. This allows air to enter and exhaust gases to leave the combustion chamber at the proper moments, which is essential for the engine to run efficiently. The camshaft does not limit engine speed or control engine temperature—those functions are handled by other components. Understanding the role of the camshaft helps you answer similar technical questions about engine operation in the future.