Yhtenäisruiskutus

Yhtenäisruiskutus, a Finnish term, translates to "unified injection" or "single-point injection" in English. It refers to a fuel delivery system commonly found in older gasoline engines. In this system, a single fuel injector is positioned in the intake manifold, typically near the throttle body. This injector is responsible for delivering fuel to all cylinders of the engine.

The fuel is sprayed by the single injector and then distributed through the intake runners to each cylinder. This contrasts with multi-point injection systems where each cylinder has its own dedicated injector. Yhtenäisruiskutus systems were an advancement over carburetors, offering more precise fuel control and improved fuel economy. However, they generally provided less precise fuel distribution to individual cylinders compared to multi-point systems, which could lead to slightly less optimal combustion and power output.

The system operates by receiving fuel under pressure from a fuel pump. The engine control unit (ECU) calculates the required amount of fuel based on various sensor inputs, such as engine speed, throttle position, and air temperature. The ECU then signals the single injector to open for a specific duration, delivering the calculated fuel charge into the intake manifold. While largely superseded by more advanced fuel injection technologies, yhtenäisruiskutus represented a significant step in automotive engine management.