What is the fuel inlet port for?

Answer 1

Situated on top of your engine block, which contains your pistons, is your cylinder head. The reason it is called a "cylinder head" is because it is situated on top of the "cylinders" which are hollow, cylinder shaped holes in an engine block which hold the pistons. The same way your head is postioned on top of your neck, the cylinder "head" is named likewise as it is on top of the engine block.

The main function of the cylinder head is to hold the valve gear, spark plugs and combustion chamber above the cylinders.

For the sake of simplicity, let's just say you have a single cylinder engine (such as a motorcycle) and, again for simplicities sake, say the cylinder has two valves situated above it.

The job of one of these two valves is to allow a fuel and air mixture to enter into the combustion chamber and the other is to allow the burnt "exhaust" to exit.

As a fuel and air mixture travels towards the valve, it must travel through a passage machined into the cylinder head, these passages are known as ports. The exhaust also travels through a port.

The stage of fuel heading toward the cylinder is known as "intake", although when talking about valves it can also be called "inlet". After the fuel has been combusted (burnt) it is known as "exhaust".

So, on a cylinder head, fuel must travel through a passage to enter into the combustion chamber. This passage is then blocked off by an opening and closing valve.

This passage is known as the inlet port or intake port.

Ports are usually matched up to an intake manifold, which are a special plate or tube system that directs fuel air mixture from a carburetter towards these inlet ports.