Sequential Electronic Fuel Injection

hi...can ne1 tell me what exactly is Sequential Electronic Fuel Injection ??.... its sum technology used in the Chevvy Spark... can ne1 tel me more abt it ??.

Hi Karan,
It is basically controlling the injectors sequentially rather than in batches. In an MPFI (multi point fuel injected) gasoline engine, each cylinder has a fuel injector that injects fuel at high pressure through a tiny nozzle into the intake manifold of the cylinder. Here the atomized fuel from the injector mixes with the air to form the "charge".
In sequential injection, the injector is "fired" exactly at the time when the intake valve for the cylinder is open. The fuel, as it gets into the cylinder, mixes with the air in the inlet manifold and this charge is sucked into the cylinder. The efficiency is generally slightly higher in sequential injection since the charge is not held is the inlet manifold (unlike in a batched injection).
Rgds
Narayan

dear mr.pai

can u pl.xplain lil more abt it. since i know very less abt intrnl combustion engine.actually i know abt 2/4stroke engine (how the cycle takes place).

regards

pallam

ISnt SEFI almost Similiar to that of MPFI ??/

Cheers,

Sri

2/4 stroke engines are internal combustion engines.
Narayana

Yes, they are very similar. The MP in MPFI stands for "multi port". The individual ports can be fed sequencially (as in SEFI) or in batches.

Isnt SEFI just a part of MPFI? I think there are different ways in which MPFI can be installed. SEFI is the most common type. There is another technology in which fuel is charged individually in each cylinder. I think Daewoo used this technique in Matiz.