[Gasification] SFC for De-rated Engines Was: small scalegasifiers for those that need them

[Mark Ludlow]

Bob & List:

Someone pointed out that a linear de-rating of diesels still requires the
same torque (read: combustion pressure). Higher RPMs imply more frictional
wear (longer distance traveled per unit of time) which, to me seems more
relevant. Taken at the limit, how much wear would one expect if the piston
were static and sealing an equivalent pressure?

Perhaps Art would elucidate us further (?)

Mark



-----Original Message-----
From: gasification-bounces at listserv.repp.org
[mailto:gasification-bounces at listserv.repp.org] On Behalf Of Bob Stuart
Sent: Sunday, July 01, 2007 10:36 AM
To: Discussion of biomass pyrolysis and gasification
Subject: Re: [Gasification] SFC for De-rated Engines Was: small
scalegasifiers for those that need them

> <snip>  Prolonging the time duration the
> rings have to contain high combustion pressures by slowing the  
> engine to a
> lower rpm than recommended is a diesel engine killer.  This is  
> especially
> true of the 20+:1 compression ratio engines in modern vehicles.
>
> Art

That is an interesting point.  At lower RPM, there is more loss to  
blow-by, although I don't see how it would increase the wear rate per  
hour.  The big diesel engines in ocean freighters are only turning  
110 RPM, and getting 50% efficiency on cheap oil.

Best,
Bob Stuart




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