Does a diesel car need glow plugs?

Answer 1

Depending on the type of fuel system, a diesel engine may or may not use glow plugs. Glow plugs are generally used on Indirectly Injected diesel engines. They are used to heat the air that is drawn into the engine when the engine is cold. Since diesel engines use the heat created by compression to ignite the fuel/air charge, Glowplugs provide easier and smoother start ups. A Direct Injected diesel engine may use an Intake Air Heater or nothing at all, since the fuel being injected into the combustion chamber is atomized to a much finer degree (and therefor ignites at a lower temperature) than the relatively low injection pressure Indirect Injection system.