tændingsøjeblikket

Tændingsøjeblikket, often translated as ignition timing, refers to the precise moment an internal combustion engine's spark plug ignites the air-fuel mixture within the cylinder. This ignition event is crucial for the efficient operation and power output of the engine. The timing is measured in degrees of crankshaft rotation relative to the top dead center (TDC) of the piston's power stroke.

Ideally, the spark should occur slightly before the piston reaches TDC. This is because the combustion process takes a finite amount of time to complete, and igniting the mixture early allows the pressure generated by the burning fuel to push the piston down with maximum force at the optimal point in the stroke. If ignition is too early (too advanced), the pressure can build up too soon, causing knocking or pinging and potentially damaging the engine. If ignition is too late (too retarded), the combustion pressure will not be fully utilized, leading to reduced power and efficiency, and increased exhaust gas temperatures.

The optimal tændingsøjeblik is influenced by several factors, including engine speed (RPM), engine load, fuel octane rating, and ambient temperature. Modern engines use sophisticated electronic control units (ECUs) to continuously adjust the ignition timing based on sensor inputs, ensuring optimal performance and emissions across a wide range of operating conditions. In older engines, timing was often adjusted manually or through vacuum-operated devices.