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Topic: Propane injection? (split from Re: No propane oil) (Read 860 times) previous topic - next topic - Topic derived from No propane oil

Propane injection? (split from Re: No propane oil)

Recent posts have led me to revisit this thread.  After reading over the older posts, and then Scott's comment, I got to wondering (again) about the exact source and composition of LPG.  This naturally required a visit to Wikipedia - my first stop in most internet info searches.  One of the Wikipedia statements caught my eye:

"Many modern common rail diesel engines respond well to LPG use as a supplementary fuel. This is where LPG is used as fuel as well as diesel. Systems are now available that integrate with OEM engine management systems."

I hadn't run across this idea before, but since we carry a large LPG supply onboard our coaches, I got to wondering if this concept has ever been implemented in the diesel powered RV market.  What would be the advantage of mixing LPG with diesel?  This will require more research on my part, but I though some of the resident Tech experts might already be familiar with the technology.  Any comments would be appreciated!

Re: Propane injection? (split from Re: No propane oil)

Reply #1 –
Yes, LP gas has been injected into the intake of diesel engines on motor coaches to provide increased power for hill climbing. LP gas is a refrigerant and dramatically cools the intake mixture and probably increases the intake air density a lot, especially after the air has been heated and compressed by the turbocharger. There's not much difference in diesel fuel efficiency but of course some propane is used. Your limiting factor is the strength of your transmission and the cooling ability of your radiator, not the power of your engine, so don't waste your time and money on this, just saying.

Re: Propane injection? (split from Re: No propane oil)

Reply #2 –
I have a propane injection system I built for my Peterbilt I have never installed it. Propane has a higher flash point than compressed diesel,so when you feed propane into the intake air stream and it enters the combustion chamber ,the diesel fuel that is injected will ignite under compression  when this happens the propane then ignites what it does is stabilize the burn of the diesel mix so more of it is burned, There is also a large increase in horsepower. My idea was that if I fed propane I would also see a increase in mpg as well.I used a propane regulator for a forklift  it is fed liquid propane.it has ports for  hot water lines to run to it,This way hot coolant water is fed to the regulator and the liquid propane is then vaporized at the regulator. The vaporized propane is then fed through a solenoid valve into the intake air duct to the turbo where it is then pressurized and fed to the cylinders. this is all controlled by a pressure switch that senses boost pressure and is adjustable to control when the solenoid opens. I built  a switch panel that I could turn it on and off with and had a couple other switches that would allow me to activate it at different boost pressures. Anyway after I crunched the cost of propane to get the extra mileage and then did some more figuring, It was going to cost too much to operate. propane cost went through the roof and i put it all in a box out in my shed.

Re: Propane injection? (split from Re: No propane oil)

Reply #3 –
Quote from: RRadio –
LP gas is a refrigerant and dramatically cools the intake mixture and probably increases the intake air density a lot, especially after the air has been heated and compressed by the turbocharger. <snip>so don't waste your time and money on this, just saying.
10+ years ago some of us experimented with using propane to cool intake air temps on blown and turbo gas engines.  It worked but wasn't easy to tune for any reliably.  In the end alcohol seemed to do a much better job, and provided more reliable results, so most of us gave up on it.  I'm pretty sure someone made 1200+ HP in a Supra using propane, but that's not really an achievement. 

Can anyone provide an idiots guide to checking for oil in the LP system?  I saw the photo of where to check, a step by step would be appreciated.

Re: Propane injection? (split from Re: No propane oil)

Reply #4 –
Quote from: RRadio –
Yes, LP gas has been injected into the intake of diesel engines on motor coaches to provide increased power for hill climbing.

It's not recommended to do it on 2strokes though. I prototype quite a bit of stuff and am probably going to work on doing a duel fuel system on a diesel engine with gasiefier gas. Anyway, there are aftermarket systems out there that do dual fuel natural gas injection. The diesel is used as pilot ignition and the gas provides most of the energy. But, only do it on 4strokes--unless the gas is directly injected into the cylinder.

Re: Propane injection? (split from Re: No propane oil)

Reply #5 –
Quote from: ScubaGuy –
Can anyone provide an idiots guide to checking for oil in the LP system?  I saw the photo of where to check, a step by step would be appreciated.
If you saw the photo, it's pretty self-explanatory.  The idea is to open the gas line at the lowest point (in the propane tank bay).  The low point is usually found in the rubber hose that connects the regulator to the gas distribution manifold.  Simply close the main valve on the propane tank, and disconnect the rubber hose at the regulator.  Let the hose end hang down and see if any oil runs out.  Reconnect hose - open main gas valve - check for leaks.  You're done.

Re: Propane injection? (split from Re: No propane oil)

Reply #6 –
Quote from: cajk –
If you saw the photo, it's pretty self-explanatory.  The idea is to open the gas line at the lowest point (in the propane tank bay).  The low point is usually found in the rubber hose that connects the regulator to the gas distribution manifold.  Simply close the main valve on the propane tank, and disconnect the rubber hose at the regulator.  Let the hose end hang down and see if any oil runs out.  Reconnect hose - open main gas valve - check for leaks.  You're done.
Thanks, that's exactly what I needed. 

Re: Propane injection? (split from Re: No propane oil)

Reply #7 –
I operated a 6208 horsepower 4.5 megawatt genset powered by a Cooper Bessemer engine from a ship. It was four stories tall with two stages of waste heat boilers on the exhaust to make high pressure steam. The engine ran on natural gas with fuel oil ignition. It started on oil with compressed air to crank the engine. After it warmed up I switched to gas and all the oil residue in the combustion chambers would burn off and smoke like crazy. Oil / gas engines are not a new idea. It's not a good idea either. That engine was documented by the government as being the largest non-industrial source of air pollution in Dallas, just saying... I heard they switched to tandem Detroit Diesel two cycle engines on a common crankshaft with the generator between the two engines after I left there... smart move :)

Ha! ...I just Googled and found a photo of that nasty engine! The control room where I used to hide is up to the top left. The high voltage switchgear is in the concrete bunker beneath. I used to sync the engine to the utility manually with a synchroscope, then close the motorized switchgear and run for my life. There's nothing I can do after I throw the switch that activates the motorized switchgear so there's no point in staying in there to die. If I misguessed and the engine wasn't perfectly in phase with the utility when the switchgear closed I'd make the evening news, in a bad way!  :o  Man that was a dangerous job. I can't believe I did that. I was a crash test dummy! ...anyway, the floor is grated and there's more high voltage stuff downstairs, and the huge air compressors that start the engine, also the lubricating oil pumps and valves. I had to pump 500 gallons of lubricating oil into the crankcase every shift from underground tank farms on site. Up the stairs you see the cylinder heads, to the back you see two huge turbochargers and the first stage waste heat boiler making high pressure steam for the turbines you can't see from here. Up on the roof is the second stage waste heat boiler making more high pressure steam. The thing sticking out to the left is the rear main bearing and the huge flywheel is inside that big rectangular cage. Those circular porthole looking thingys on the side of the crankcase are explosion doors ...trust me, you don't even wanna know why those are there ...the mechanics would take one of those explosion doors out, climb inside, and shovel out the oil sludge into wheelbarrows during oil changes. They filled up a dumptruck with oil sludge and hauled it to a hazardous waste site. Oh the bad memories this brings back! hahaha ...soooo glad they switched to Detroits