käynnistysrikastinta

Käynnistysrikastinta, also known as a cold start enrichment device, is a component found in some internal combustion engines, particularly older gasoline engines. Its primary function is to enrich the fuel-air mixture during cold starts, making it easier for the engine to ignite and run smoothly when cold.

When an engine is cold, the fuel tends to condense on the cold intake manifold walls. This means less fuel vapor reaches the combustion chamber, resulting in a lean fuel-air mixture. A lean mixture is difficult to ignite and can cause the engine to stall or run poorly. The käynnistysrikastinta addresses this by temporarily injecting a small amount of extra fuel into the intake system, effectively increasing the fuel-air ratio to a level suitable for cold combustion.

There are several types of käynnistysrikastinta. One common type is the cold start injector, which is an electrically operated fuel injector that opens for a short period during cranking when the engine is cold. Another type is the over-run enrichment device, which enriches the mixture when the throttle is closed. The exact operation and presence of a käynnistysrikastinta depend on the engine's design and the era of its manufacture. Modern engines with sophisticated electronic fuel injection systems often manage cold start enrichment electronically without the need for a dedicated mechanical device.