What is Direct
Fuel Injection and How Does it Work?
- Direct
injection is similar to the old electronic
multi-port injection systems and
carburetors. All the systems get vapor fuel
into the combustion chamber for ignition.
However, direct injection has some key
differences that set it apart:
- Direct injection has a
of method of getting pressurized (up to
around 2000 psi of fuel pressure, according
to AASA know your parts) vaporous fuel
(gasoline or diesel) into anengine's
combustion chamber. This is accomplished by
'directly' injecting it straight into the
chamber through a direct injector that is
actually inside the chamber. Neither a
carburetor nor a multi-port injector can do
this. They both vaporize the fuel outside of
the chamber and rely on the camshaft and
valve system to let the fuel inside the
combustion chamber.
- Direct injection has the
capability to stop blowing fuel out of the
exhaust (because of difference one) if the
system is precisely timed. The fuel is
quickly injected into the chamber, and then
immediately ignited. This is done fast
enough to allow both air and exhaust valves
to be closed while fuel is injected when the
fuel is ignited. On the older fuel systems,
many engines have to keep the exhaust valve
open even while new fuel was coming in. This
means the engine would literally pull fuel
into the combustion chamber and blow it out
the exhaust without using it.
- Direct injectors have
traditionally had issues with gumming up
combustion chamber and causing carbon build
up. This carbon build up becomes a large
problem when the injectors stop injecting,
valves refuse to close, or the engine has
predetonation issues (abnormally high
pressure igniting the fuel before it's
supposed to). This is actually the
main reason why direct injection wasn't able
to be used in the past. But thanks to recent
developments in technology, engineers have
lessened/solved the issues.
example to how a
direct injection system works
(http://www.autoguide.com/auto-news/2012/12/should-you-buy-a-car-with-direct-injection.html)
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