[Vwdiesel] stuck stick in cylinder & Engine refresher: Thoughts?

[Tad]

I thought the prechamber was because the IDI pumps don't generate enough
pressure to inject directly?

Rotary-pump TDIs don't really have multiple injection events, but they do
have two-stage injectors that(as you mentioned) have a smaller "pilot"
injection prior to the main injection event.

Newer CR engines with the piezoelectric injectors do true multiple
injections... not sure about PD.

On Tue, Dec 13, 2011 at 8:14 AM, <LBaird119 at aol.com> wrote:

>
> In a message dated 12/12/2011 11:43:49 P.M. Pacific Standard Time,
> tgott at hotmail.com writes:
>
> But it  is true about the cup in the TDI piston that basically acts as the
> prechamber  for lack of better terms on the IDI's. It helps contain the
> explosion of the  fuel and hence the knock of the diesel is less for this
> style
> of engine.
>
>
>
>
> I wouldn't put it quite that way.  Maybe I'm wrong here but the  purpose of
> a
> prechamber, IDI, is to make a quieter idling engine, mostly.  The dish  in
> the
> piston isn't so much to replace the prechamber, it's the combustion
> chamber.
> The shape is to make the best mix of the air/fuel in the cylinder.   Same
> for the
> spray pattern and angle of the nozzle used.
>
>  The newer diesels (one of the first to incorporate it was the TDI)  use
> multiple
> injections per injection cycle, to make the engine quieter.  I believe  VW
> uses
> two bursts, a light one to start ignition slowly (to greatly reduce the
> sudden
> pressure rise knock) then the main injection.  I forget which engine I
> read about,
> that uses 5.
>     Loren
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