This is interesting, I had no idea those mechanical injection systems
were continuous flow. Strikes me as a nasty way to deal with part
throttle fuel metering. How about closed throttle on overrun? Do
they still flow fuel? This would cause a very rich mixture when you
crack open the throttle again.
As a matter of interest, the mechanical fuel injection used on Alfa
Romeo cars in the USA up until the mid 80s I think, has systems to
compensate for engine temperature, barometric pressure and throttle
position, plus its fully timed. Its quite a nice little piece of
mechanical engineering. Not as accurate or easy to set up as a good EFI
system but it works amazingly well for something that was first
released in the early '70s.
Ed
Monday, April 29, 2002, 11:37:41 AM, you wrote:
AN> Dick;
AN> A continuous- flow FI system such as the Hilborn, Crower, Kinsler, Algon,
AN> etc., simply sprays fuel continuously from each injection nozzle. The amount
AN> of fuel delivered depends on the injector orifice size and fuel pressure.
AN> The fuel pressure is controlled by a barrel valve that is opened & closed by
AN> the throttle position. There are also other controls such as fuel return
AN> jets, etc. that allow the fuel delivery curve to be tailored to the engine's
AN> requirements. This type of system isn't timed at all-- fuel is spraying into
AN> the intake port even when it's closed. As a result, some fuel condenses out
AN> onto the intake runner walls during this period.
AN> A timed mechanical injection system such as the Lucas or Tecalmit- Jackson,
AN> is similar but it sprays fuel intermittently from each injection nozzle,
AN> timed for when it is the optimum point for that cylinder to receive it. This
AN> improves the efficiency of the mechanical system.
AN> Both types of mechanical FI systems work well for full- load operation but
AN> they don't compensate for light engine loads, temperature, barometric
AN> pressure, etc., etc. EFI, on the other hand, provides an automatic
AN> adjustment for a whole host of engine parameters and essentially "optimizes"
AN> the fuel delivery based in the engine requirement at that particular
AN> instant.
AN> Everybody has their own variation of these basic systems but their
AN> fundamental principles are similar.
AN> Regards, Neil
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