It can be argued that the diesel and petrol fuel delivery systems are entirely different. It can equally be argued that in modern marine engines the difference lies not in the delivery of the fuel, but in the engines they deliver to.
In marine diesel engines the fuel is injected directly into its combustion chambers (cylinders) where it mixes with hot air and ignites by compression. In petrol engines it is delivered to one or more pre-combustion chambers where it mixes with cold air and then enters the cylinders to be ignited by spark plugs.
The pre-combustion chamber is traditional petrol engines is the carburettor. In the modern EFI engines it is the intake manifold, which is located just before the intake valve of each cylinder. petrol was pumped into the carburettor, but in the EFI engines it is injected by a fuel injection system similar to diesel engines.
Marine Diesel Fuel Delivery – Tank To Engine
In its simplest form, the fuel flows from the tank, through the primary filter, to the fuel lift pump. It then flows through a secondary filter to the fuel-injection pump, to fuel injectors, which squirt it directly into the combustion chambers (cylinders).
The fuel injectors are usually delivered more fuel than is required for combustion. The excess is returned to the fuel tank, taking with it small amounts of air entrained in the supplied fuel.
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