Propane injection on big cam cummins?

Truck is now operated by Rivet.
Same people running the fleet as far as I know, but different owners and different name.

They run a few Volvo's and a Kenworth with propane, as part of a project to get legislation changed to make dual-fuel road-legal, and to have homologation procedures set up.
Has been going on for at least 4 years now.

 

Though it was on a SI (gasoline) engine, I had a chance to check out and drive a rousch propane in a Ford. If I remember right, it was was injected as liquid vs vapor and didn't have near the power loss. Not even sure if it is still available.

 

another thing to take into consideration on the pricing would be that cng is not as dense as diesel fuel. i don't know the figures off the top of my head but say for example to reduce diesel by 20% you might have to use 30% in cgn meaning your using 110% of the fuel you would be on diesel alone. to do the same amount of work. i wonder how that plays out for fuel tax as well.

i could see it being viable for local/short haul company's where the trucks return to the yard every day.

edit: i guess you did include the energy density in your calculations i must have missed that the first time i skimmed threw it.

 

every gas engine converted for propane iv ever messed with (mostly ford industrial engines) in things like forklifts and big ride on sweepers and stuff like that. draw liquid propane from the tank and then it goes threw a mixer (carburetor) and then into the intake. so the propane is not still liquid as it enters the intake. but draws liquid propane from the bottom of the tank vrs vapor like a bbq grill or gas stove ect.

 

Still in business, here it is:
Fuel System Overview - ROUSH CleanTech

 

interesting system much like modern multiport fuel injection only using propane. iv never come across one of those systems before...lol pretty cool

 

On the liquid injection systems you may actualy see a small power gain, but usually not enouogh to notice.
This due to the evaporation of the liquid propane inside the manifold. It cools the intake air, making it denser, and the engine can swallow a larger mass of air.
And on a stoichiometric or rich-burn engine (like gasoline or propane) more air means you can burn more fuel > more power.

On (sequential) vapour injected engines there is usually a small drop in power, but again not enough to really notice.

On the older systems with the Impco-style carburettors there is a noticable power loss, mainly because of the rather large pressure drop (for the intake air) across the carburettor, specially if the Impco carburettor is installed on top of the gasoline carb


There are also several systems on the market for the Direct Injection spark ignited engines that inject the propane through the high pressure gasoline injectors.

A low pressure pump (inside the propane tank, similar to what Roush use) feeds the liquid propane to the high pressure gasoline pump, which pumps the propane to the gasoline injectors.
High pressure pumps are modified to accept a fuel return line to the tank to prevent vapour lock in the low pressure system. The continuous return flow of propane is used to cool the pump and keep the propane below the boiling point.

 

There is a good reason why acetylene is used in a cutting torch. Flame temperature of acetylene is much higher than most other fuels.
Think of what acetylene can do to a thick steel plate......now think of the pistons in your engine.
Still think it's a good idea?


The gas produced at landfill or sewage plant is methane, but there will be carbon-dioxide (CO2) as well, and contaminants (water, sulphur, siloxanes).
Methane percentage in unthreated landfill gas is often only 40-50%, 50-70% in sewage gas, and it fluctuates.
After filtering and some cleaning it can be a good fuel for a stationary engine/generator on landfill site or at the sewage plant. They often use an analyzer to measure the methane content of the gas and adjust the fueling to the engine accordingly.

For a truck it is less suitable, because you will have limited fuel storage as it is. You don't want to carry any carbon-dioxide in your tanks, taking up the space that could be used for fuel.
Also, you won't have any indication of the fuel composition, no methane analyzer on board of the truck, to adjust the fueling.

If the landfill gas or sewage gas (or any other biogas) is threated properly, and the carbon-dioxide and contaminations are removed, it is perfectly possible to use it in a truck.

It's already happening, garbage truck running on the gas produced and processed at the landfill site, trucks running on the biogas which is a by-product of the sugar refineries.
Or feeding the processed biogas into the natural gas pipeline network.


Just one example:
Subcontractors for this dutch sugar company have been running dual-fuel (diesel-biogas) trucks for about 8 years.
Untill recently the spark-ignited natural gas engines (in Europe) did not have the torque/power for 110k lbs gross weight.
More powerfull spark-ignited trucks have become available now from Iveco and Scania, so they are evaluating these now.

Suiker Unie - New bulk trucks running entirely on Suiker Unie’s own green gas


Dual-fuel (diesel-biogas) MAN for sugar transport


Spark-ignited Scania

 

For those interested, look behind the cab of the trucks and you can see the CNG cilinders.
Just a few of about 2000 dual-fuel trucks operated by this fleet.