Glühkerzen

Glühkerzen, often translated as glow plugs, are essential components in diesel engines. Their primary function is to facilitate the cold start of the engine by preheating the combustion chamber. Diesel fuel requires a high temperature to ignite spontaneously. In cold conditions, the engine block and the air within the cylinders can be too cool for ignition to occur reliably.

A glow plug consists of a heating element, typically a coiled wire made of a special alloy, encased in a protective metal sheath. When the ignition is switched on, an electric current flows through the heating element, causing it to heat up to a high temperature, often exceeding 1000 degrees Celsius. This heat is then transferred to the surrounding air and the pre-chamber or combustion chamber of the cylinder.

Once the engine is cranked, the compressed air in the cylinder reaches a temperature high enough to ignite the injected diesel fuel, aided by the residual heat from the glow plug. In many modern diesel vehicles, the glow plugs remain active for a short period after the engine starts to ensure smooth idling and reduce emissions, a process known as post-glow. The duration and temperature of glow plug operation are controlled by an electronic control unit, which monitors engine temperature and other parameters. A faulty glow plug can lead to difficult starting, rough idling, increased smoke, and reduced engine performance.