From: "Gary Britt" 

Thanks that was an excellent explanation.

Gary

"Don Hills"  wrote in message
news:jYOoDtgaXWjW092yn{at}attglobal.net...
> In article ,
> "Gary Britt"  wrote:
> >Well that would be a big improvement.  What does CRD stand for?
>
> Common Rail Diesel.
>
> Old petrol engines used carburettors. Modern petrol engines use fuel
> injection - originally low pressure into the inlet manifold, and currently
> changing to high pressure injection direct into the cylinder, often called
GDI
> (Gasoline Direct Injection). Fuel injection systems use electromagnetic
> valves to deliver fuel from a pressurised pipe known as a "fuel
rail" or
> "common rail".
>
> Diesel engines have always used direct high-pressure cylinder injection.
> Originally this was done by a mechanical pump with one pump mechanism per
> cylinder. Modern diesels use an electronic injection system very similar
> to that used for GDI petrol engines. They are called "Common
Rail" engines
> to differentiate them from the old mechanical injection systems.
>
> Changing to electronic control allows several advantages. For example,
> mechanical injection systems had no way of telling if too much diesel was
> being injected under high load. Excessive fuel results in black smoke.
> Now they can use an oxygen sensor similar to that used on petrol engines
to
> prevent "over fueling". They can also vary the injection timing to
optimise
> power, emissions and noise under combinations of load and RPM.
>
> --
> Don Hills    (dmhills at attglobaldotnet)     Wellington, New Zealand
> "New interface closely resembles Presentation Manager,
>  preparing you for the wonders of OS/2!"
>     -- Advertisement on the box for Microsoft Windows 2.11 for 286

--- BBBS/NT v4.01 Flag-5