Testing for legal fuel 3

[racerm]

I am the head of a large road racing santioning body in California. A number of our classes have rules on types of gas. All do not allow "additives". It's common practice to buy "$30/gallon" gas that will pass the dialectic? test.

I have two questions:
1) If there any at track testing (preferably fast)that will detect non comlpiant gas?
2) If we wanted a rule requiring use of "track gas", how can we test to match the track gas to what's in a racers tank.

Thanks for your help

 

[patprimmer]

Add a dye then test for the dye.

A simple colourimeter will accurately identify the dye.

Specific gravity also helps to indicate if a change has been made.

At laboratory level you could run a gas chromatograph, but this is an expensive, non portable (last time I looked), complex piece of equipment.

A third method could be to build a test engine. A simple single cylinder will do. It needs to be extra tough so it will last running in knock.

Set it,s compression ratio so that the specified fuel just knocks. Test supplied fuel and sample back to back. and see if they knock the same. This test the performance rather than the formulation of the fuel. Any increase in antiknock indicates cheating.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[reidh]

You could also use a portable octane analyzer, although this would be only part of the equation. Zeltex makes pretty reliable "field" units:

http://www.zeltex.com/products.html

-Reidh

 

[patprimmer]

IR analysis will determine amounts of specific chemical substances, but if the additive is not in the machines built in data base, the variation will slip by.

The only real way I know to check knock is on a test engine.

Knock can be predicted by knowing the formulation then comparing to data collected by test engines, which is what this analyser appears to do, but you need to be sure the cheater chemicals are included on the instruments inbuilt database.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[PhdDave]

You might check with the gasoline's supplier as many of them use an Isotrace florescent additive put in at the factory that shows if you have the real article,or if it has been adulterated. The use of the meter to check for the compliance of a sample is simple and quick,just standardize to a known sample and then run the ones you want to test and the machine will show the change by dilution to as little as 2%. You set the limits as to what you will accept to be compliant to the rules.

If you have a dielectric constant meter such as those used by NHRA and SCCA you can tell if there have been any additions by the change in the DC number compaired to a known sample if the temperatures are within 5 degrees F.One of the suppliers of this equipment can be found looking at the SCCA and NHRA websites.
Have a safe race season.

 

[btrueblood]

"and the machine will show the change by dilution to as little as 2%"

But, ethyl lead and MMT (Methylcyclopentadienyl manganese tricarbonyl) can significantly change fuel octane numbers in ppm dosages. Pat's method might be a better one (and, indeed, is the test method for determining fuel octane ratings), unless a detector(s) specific to all of the various additives in their effective dilutions is available.

 

[racerm]

Thanks for the ideas. What makes this difficult is legal gas can be everything from standard pump gas purchased from a gas station, to higher octane race fuel (sold at race tracks), to race gas purchased in barrels from companies like VP Racing Fuel. The less than legal additives have been masked to get by the SCCA standard testing.

 

[patprimmer]

If octane rating is unrestricted, what are the restrictions.

From the tone of the OP, it seemed you had a specified or controlled fuel.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[1BAD801]

You can buy a testing unit from NHRA, we have one for our nitro/alcohol ratio.
The ones they have checks for anything added to the gas and tells what the gravity is.

 

[PhdDave]

Octane is only useable if the compression ratio of the engine is high enough in the first place.
It appears that your santioning body is not willing to be the enforcer of the rules. If you state in your rules for the race that all cars must use the fuels as purchased from the track, then you can accurately check for the use of that fuel by
1.Check the color of the sample to a sample of track fuel.
2.Check the dielectric number from a digitron or G-01 dielectric constant meter and a known sample.
3.Check for oxygenates by using the Germain Reagent A test liquid but be aware that there is an oxygenate that it will not detect.
4.Check for masking agents by not allowing the black Reagent A test.
5.Check for the specific gravity.
6.Check for a fingerprint of known fuels using a FTIR and you can get a good idea of the working of this at

http://www.wearcheck.ca/literature/techdoc/WZA002.htm

What fuels are available at the track, brand and type?

There are some fuels made that are closer to $50.00 per gallon that do produce more power, but if someone is willing to spend that kind of money they are just as likely to have bought high compression pistons or cams that don't meet the rules.

 

[petrochemist]

I've been involved in trackside testing of control fuels for over ten years.
If the regulations specify a particular fuel is used, then FTIR fingerprinting can readily confirm that the fuel used is the same as the control fuel.
Changes in batches of a particular fuel have been identified by me at race meetings with this technique.
Normally the test takes under 5 minutes per sample, though rapid variations in the local atmosphere can cause problems. (Too many people breathing in the area is most common causing CO2 levels to vary).

We've found a correlation factor of 0.9995 to be consistently acheivable on post race samples. For use in hotter climes & long races evaporation from the fuel tank might change the composition of the fuel durring the race to the point that a lower correlation is needed, but I've never seen this in the UK.

Most of the non-conforming samples I've met have later turned out to be remaining fuel from previous events/ suspension set up etc. using the same control fuel all year prevents this problem.

Since FTIR fingerprints the chemical bonds in the sample, any additives with chemistrys different to the control fuel are fairly obvious even at low concentrations, those with similar chemistries will make less difference to the fuel so less sensitivity to them is needed.

GC can be used at the racetrack, but the equipment is generally less rugged & takes longer per sample. (The Formula 1 trackside fuel testing method takes 30 minutes + cooldown time per sample - before the data can be reveiwed)
Mike