Exhaust emissions: LPG vs Unleaded fuel 2

[Peter7307]

Does anyone have any information of the different levels of exhaust emissions for the same engine running on the two different fuels mentioned?

Is it 5% , 50% someother number?

So far as I can find there is a reduction when running on LPG but the amount of decrease is not stated.

Thanks, Pete.

 

[franzh]

It all depends on the controls, for either fuel. LPG engines can be very clean, cleaner than unleaded, but also dirtier. Unleaded engines can be cleaner than LPG, but also dirtier.

Its not the same world today with LPG vehicles. It is for all purposes next to impossible to bolt on mechanical components on a late model vehicle and make the engine cleaner than unleaded, it takes sophisticated electronic fuel management and injection to at least equal the unleaded engines emissions performance. Like it or not, the playing field needs to be equal now between unleaded and LPG emissions performance.

Franz

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[Azmio]

from the literatures that I have reviewed, the raw emission of fossil gaseous fuel is around 20-30 percent better

 

[TStaples]

Peter7307,

I don't have percentages to share, but Azmio's numbers look about right. Based on my prior experience at a major tier 0.5 upfitter/converter (

http://www.qtww.com)

an engine being converted to LPG from Gasoline generally improved one EPA tier rating. For example, if the engine was rated a LEV II, converting to LPG generally improved it to SULEV. A SULEV generally improved to a SULEV II, etc . . ..

Now that being said, we had all of the same engineering talent that any OEM had for doing calibrations and emissions certifications. Franzh is correct, the controls and calibration have to be top notch, and a botched job could easily result in a higher emissions engine on LPG.

-Tony Staples

http://www.tscombustion.com

 

[Lou Scannon]

For what it's worth, I concur with Franz & Tony.

 

[rdd48856]

Tipically in a dual-fuel Euro3 engine converted with sequential gaseous injection you get about 68% less NOx, 26% more CO, 19% less HC and 11% less CO2, with a mix of 50% propane and 50% butane, compared with gasoline. With 95% propane you should get more CO, less NOx and less CO2.

 

[Peter7307]

Thanks to all who replied.
The numbers provided are a big help.

Pete.