🚀 go-pugleaf

With all this talk about fuel injection, I thought I would post this
summary of fuel injection systems. Most of what is presented here
is from a technical session Bosch gave to the BMW Car Club of America 
at the annual meeting in Oktober. 

There are three types of injections systems:

  Single point
    -- Most often used by American car companies.
    -- One injector feeds multiple cylinders. Injector is not near
       the intake valve, it is a the head of the intake manifold. 
    -- Basically a carburettor tuneable via electronics.

  Multi point (non-sequenced)
    -- Most often used by European car companies.
    -- Usually an injector for each cylinder. Sometimes an injector will
       feed multiple cylinders (one injector for two cylinders). The injectors
       are close to the intake valve (at the base of the intake manifold).
    -- Injectors all release a charge at the same time. Charge stays above
       the intake valve until it opens. The charge is "inactive" for a very
       short period of time (milliseconds). 

  Multi point (sequenced)
    -- Same as non-sequenced except injectors fire just before intake 
       valve opens. The charge is never "inactive".
    -- Not used much because there is marginal gain over non-sequenced. The
       difference is barely detectable on the dyno and does not warrant
       the added complexity.

This just describes the injection of a charge. The control system is a
another story.

I suspect most of the confusion about fuel injection comes from marketing
people. They have a real gift for taking something simple and giving it
hundreds of different names...


-- 
/%%///%%  Craig Hockenberry
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/%%//%%%  "The stuff of thought is the seed of the artist" - Arshile Gorky, 1942