Propane fuel alternative

[Scifiguy]

What are the pros/cons of using propane as an alternative to conventional gasoline? What type of A/F ratios are used; ie comp ratios per spark timing?

 

[patprimmer]

Why do you ask

Have you tried google and wikipedia

Is this a homework project

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules

 

[Scifiguy]

Im concidering experimenting with propane on one of my engines.

 

[patprimmer]

It may be a lot cheaper depending on where you live.

It runs hotter.

It is dry so it does not dilute oil so much.

Fuel does not puddle in manifolds and cause poor distribution.

I won't guess if you are talking FI or carby. You need to tell me.

Availability.

It is normally over 100 octane, depending purity of the propane.

The tank is heavy and restricted in shape which complicates packaging.

The capital outlay is substantial.

The ignition system will need recalibrating.

If it is left as dual fuel, the engine cannot be well calibrated to both fuels.

A complete text book will cost more, or you could do a google search of the site and read all the previous threads.

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules

 

[FOURe]

Here is a URL where you can find a spreadsheet to help you out with combustion calculations for your combustion conditions:

http://www.engineering-4e.com/eng-tips/combustionwithplots.xls

For example, one can easily calculate oxidant (air) to fuel ratio values for given fuel and oxidant composition.

I have to warn you that the spreadsheet does not directly deal with propane -- C3H8. However, one can always deal with solid fuel having a mass composition of C = 0.818182 [kg/kg] and H = 0.181818 [kg/kg]. In order to get the combustion products flame temperature, one needs to make some minor enthalpy adjustments in the spreadsheet.

Propane fuel composition contains more carbon than gasoline resulting in having more CO2 in the combustion products for stoichiometric combustion conditions -- if the combustion products flame temperature is maintained at a fixed value, my assumption may not be true ...

http://www.engineering-4e.com

 

[Scifiguy]

I would hope FI. What numbers of compression would I be looking at?

 

[FOURe]

Here is a URL for some online calculators regarding basic power cycles:

http://www.engineering-4e.com/calc3.htm

In my opinion, the compression ratio based on volume basis is around 10 [/].

http://www.engineering-4e.com

 

[drwebb]

Didn't the old street vehicle propane conversions just have some kind of simple metering orifice replacing the carburetor? I don't understand the need for needle/pintle EFI where liquid atomization isn't an issue.