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Old 11-09-2010, 12:38 PM
IDI IDI is offline
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Join Date: Jul 2010
Posts: 6
Default Re: WI on IDI 1.9 Turbo Diesel

Quote:
Originally Posted by nutron View Post
One thing I am interested by is the knock, as the auto ignition point of methanol is significantly higher than that of diesel (diesel = 210 C, methanol = 470 C). So in order for the methanol to be pre-igniting, you would have to have unthinkably high cylinder pressures, that would without a doubt be giving massive rises in EGTs if the engine was actually capable of withstanding them (which I find implausable at best). So I think you need to look to a different reason for this knocking sound, which may well be the methanol but not as you think. The specific heat capacity of water of massive, that's why we use it for cooling, fighting fires, e.c.t. Methanol however isn't as good and as though it would cool the intake charge, on it's own it could expand and create higher cylinder pressures and temps (this is only a theory). If you have a non-dirrect diesel injection with a pre-ignition chamber, the diesel might be igniting at the wrong point, or it might be igniting, and creating a sufficiently high temp to then ignite the methanol in the cylinder before the flame wall reaches it. With a direct injection engine, the fuel is injected at the point it is supposed to ignite and that would remove the possibility I would have though.
Everything's conspiring against me lately (boost gauge and EGT probe failures to name two) so I've made no progress to speak of except to report that I tried propane fumigation and got the same, maybe a little less pronounced knock once sufficient quantities are injected.

BTW, yes, mine is an In-Direct Injection diesel engine with prechambers.

If the knock is not pre-ignition then I'm at a loss to explain it (detonation maybe?) but would maybe give reason as to why my engine is still in good working order, for which I'm grateful.

As regards my fuelling vs boost (without WI), it puffs a small cloud of soot/haze during boost lag but once up to peak boost, there's no noticeabe smoke (viewed in mirrors).

Last edited by IDI; 11-09-2010 at 12:55 PM.
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