[Dougal]

I read an interesting article today. Scania convert diesel engines to run on ethanol by cranking the compression ratio to 28:1.
They're using them in city buses with a hybrid drivetrain (electric CVT with big capacitors on the roof).

So anyone want to crank up the compression on their cummins?:grinpimp:

 

[LincTex]

I read an interesting article today. Scania convert diesel engines to run on ethanol by cranking the compression ratio to 28:1.
They're using them in city buses with a hybrid drivetrain (electric CVT with big capacitors on the roof).

That has got to be a really efficient engine, but the tolerances have got to be really close to get 28:1. Combustion chamber must be 15 cc's or so!

 

[rbarnett]

That has got to be a really efficient engine, but the tolerances have got to be really close to get 28:1. Combustion chamber must be 15 cc's or so!

Where do you come up with an arbitrary "15cc's"? The combustion chamber size as related to compression ratio depends on the size of the engine. It is not a set volume.
Bob B.

 

[Diesel Durango]

in the 4bt, approximately a 1L/cylinder displacement, the combustion chamber would be almost 36cc's.

 

[LincTex]

Where do you come up with an arbitrary "15cc's"?

Just a random small number.
This is the first I have ever heard of any piston engine approaching 30:1.
I believe the highest compression ratio I had heard of previously was 24:1

 

[Dougal]

I think it was on a 9L, 5 cyl engine. Strange configuration I know.
That'd give a head volume of approx 64cc.

 

[LincTex]

I think it was on a 9L, 5 cyl engine.

weirder than weird

 

[cRiPpLe_rOoStEr]

compression-ignited ethanol engines are used in brazil since a long time ago, but retained the original compression ratio... the main problems are the cold starts (in some cases there are 2 injection pumps: one to cold starts using diesel and the other to the ethanol running, but if there wasn't enough ethanol diesel could be used without any trouble) and the fuel pump lubrication and the rusty effects of the ethanol in some metals, but are almost 100% solved... with the common-rail systems diesel and ethanol can be more easily blended in any proportion, just like in a flexfuel gas/ethanol engine... mwm, brazilian subsidiary of international engines, made a lot of dual-pump diesel/ethanol engines for tractors and trucks (mostly dodge and volkswagen, but some ford trucks used those engines), and a co-development for a tri-fuel engine to run on ethanol, gas and diesel is on course with mahindra because of a brazilian stupid law that forbids the usage of diesel in a 2wd vehicle with payload lower than a ton, like mahindra xylo, that is currently being made in india just with a diesel engine option...