College

In a normally operating engine, intake and exhaust valves are opened by a cam and closed by the:

A) ECU (Engine Control Unit)
B) Crankshaft
C) Valve springs
D) Rocker arms

Answer :

Final answer:

The intake and exhaust valves in an engine are opened by a cam and closed by the valve springs. The valve springs apply pressure to ensure that the valves close properly after being opened by the camshaft.

Explanation:

In an internal combustion engine, the camshaft plays a vital role in operating the intake and exhaust valves. The camshaft is equipped with lobes that act as eccentric cams, causing the valves to open and close at specific intervals. When the camshaft rotates, the cam pushes against a valve, overcoming the resistance of the valve springs and causing the valve to open. However, to ensure proper engine function, it is crucial for the valves to close promptly and securely after opening.

This is where valve springs come into play. Valve springs exert continuous pressure on the valves, acting as a mechanical force that counteracts the camshaft's action. By applying tension, the valve springs ensure that the valves return to their closed position efficiently, preventing any delay or incomplete closure. This synchronized operation between the camshaft and valve springs is essential for maintaining optimal engine performance and efficiency.