Why the Diesel Is Noisy

GENERAL INFORMATION

The familiar diesel knock is caused by fuel ignition and the subsequent rapid pressure rise in the combustion chamber. The characteristic diesel clatter is most clearly heard after starting, while the engine warms up at idle.

A diesel has no ignition system, but it has a cylinder combustion chamber preheating system using glow plugs. In addition, the times of prolonged cranking with the starter and long waiting until the glow plug indicator light goes out have long passed. Many manufacturers now produce quick-start diesel engines that need only a couple of seconds to start in winter. Some vehicles even have a "starting lever" that directly controls the high-pressure fuel pump to change injection timing, speed up warm-up and reduce smoke at startup.