Abstract
The presence of time delay in a conventional starting system of a marine large diesel engine makes it difficult to open and close the starting valve at most suitable timing for starting and braking in different engine speed. The time delay occurs mainly in pressure transmission in the pipe of pilot starting air between the starting air distributor and the starting valve.
In a new starting system, ECSS, the time delay is calculated and compensated by electronic controlled circuit so that it can drive the starting valve at most suitable timing for starting and braking respectively, even if the engine speed may change rapidly. The ECSS adapts magnetic valves to the starting air distributor. They are controlled by a micro computer where the engine speed and the crank angle are sampled by using an encoder fitted at the end of cam shaft.
From the result obtained through the test engine (NKK-SEMT 3PC2-5L) experiments, it is proved that the starting performance is improved remarkably compared with the conventional, mechanical starting system. As for braking performance, it is found that the starting valve can be controlled beyond the limitation of conventional effective braking speed.
