running on diesel and lpg

[peterdiesel]

am running a diesel engine on diesel fuel injected in the normalmanner , and injesting lpg at the same time.
all seems to be well except i need to know ideal volume of gas to injest . i know the combustion requirements running on diesel only , need to know if the aprox 50% excess air volume can be used to burn the lpg at lambda 1 ie afr of 15.5 : 1 from this i can work out the volume of gas to injest . any ideas would be wecome

thanks and regards

 

[rmw]

This has been discussed previously. Did you do a search on this forum?

rmw

 

[patprimmer]

The google search works best

Regards

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[marcdeluca]

I have lp injection on my Duramax, I typically use 3 gal of lp to 1 gal of diesel fuel.

 

[rdd48856]

marcdeluca, I suppose you are getting very high HC values...

 

[marcdeluca]

I don't think they are high unless it is running at high load and getting overfueled, which I don't let it do. The lp should be cleaning up the emissions. The oil sure does stay cleaner.

 

[rdd48856]

A Diesel engine is not designed to have fuel far from the injector (in combustion chamber walls). This fuel will not be burned.
Usually the incoming air is used to wash out burned gases. If this incoming air is pre-mixed with fuel it will, once again, increase HC. You are getting fewer particles but much more HC.

The substitution limit is about 15% Diesel replacement.

The only way to avoid these problems would be using a dual injector, with injection spitted in several steps.

Did you ever read HC emissions of your car?

 

[marcdeluca]

I have not checked the HC on the truck, we don't have emission testing where I live. It is my understanding that when a diesel engine inhales a homogeneous mixture of a vapor fuel, it enables much more of the oxygen to be burned that is far from the injector. The diesel fuel only has time to combine with some of the oxygen, leaving the O2 at the cylinder wall unused. I believe this is occuring because the boost drops by more than half with a constant load, such as 70 mph on a level road with cruise control on. I believe this is the same reason that it raises power output, not just because of more fuel. Even a diesel engine loaded to the point of smoking from overfuel will have unburned O2 in the exhaust. The gas enables better use of the available O2.