Compression ratio

[Weatherlawyer]

What sort of compression ratios would LPG work best at? I noticed a diesel in the conversion shop this morning.

Is butane high octane. I imagine it is better than alcohol but don't have a clue where to look.

[tabbypurr]

What does google give you from LPG compression ratio butane octane ?

[Dave Plowman (News)]

Not an expert on LPG, but have read it works better with a lower compression ratio than petrol. Which would make diesel far too high.

Petrol engine conversions will usually run on either. Can this be done with diesel?

[harry]

No. The fuel pump is lubricated by the fuel. Very large diesel engines can be run on a mixture of oil and gas.

[Chris Hogg]

I assume you're not using the term 'gas' in the American sense. So how does it work? How can you have a mixture of oil and gas? Is it a froth of some sort, if so how is it metered into the cylinder, or does the gas actually dissolve in the oil?

Or are you thinking of gas-oil, i.e. diesel?

[Tim+]

Inject diesel as normal (or rather in reduced quantities) and add lpg to the inlet manifold.

Gains are less than lpg conversions for petrol cars so generally not economically viable except for large/high consumption engines.

See

Tim

[Chris Hogg]

All is explained. Thanks.