Propane and/or Water injection

[Garymci5]

Being new to this forum I'm wondering if anyone has any experience with either Propane or water injection on their bus. Did you buy a kit or make it yourself and how well does it work. What infinite wisdom can you impart to someone that wants to get a little more oomph (from the diesel engine) for the hills?

Thanks for anything that you know of or links to find out more info..

[Jeremy]

As far as propane injection is concerned, I cannot remember it ever having been discussed here previously, so there is probably not much direct experience to be shared - but no doubt there are  diesel-engine forums out there that have discussed such projects in great detail. Regarding water injection - presumably you would only do this if you were running some fancy high-pressure forced-induction system?

Jeremy

[junkman42]

As an older retired military person that spent many thousands of hours flying on aircraft with reciprocating engines My personal experience is that what We called ADI means  simply water and alcohol injected at METO power to prevent detonation at high power settings.  Detonation in this context means preignition.  At high boost pressures even with 115/145 octane aviation fuel ADI prevented cylinder failure at high power settings usually meaning takeoff power.  60 inches of manifold pressure is a feared thing on a hot day with maximum weight etc.  Propane injection is a totally different principle with diesel engines.  For information buy a copy of one or more diesel enthusiast magizines.  Water injection with a diesel engine should be avoided like the swine flu viruses.  Regards , john

[JackConrad]

BullyDog makes an LP injection system for diesel engines, but I don't think they make a model for 2 strokes DDs.  Jack

[Jerry32]

I had proopane injection on a cummins in motor home that worked ok . it was activated by boost so it would turn on at 8 lbs and increase as the boost increased.  at 38 lbs of boost it was at max. I The propane was simply injected at the intake to the turbo. I think I still have the system as I took it off when I solt the rig Jerry

[bobofthenorth]

George Lowry ran a propane injector on his Cummins repower.  If you want to talk to him contact me offline and I will give you his coordinates. 

[Damn Yankee]

It has been discussed many times on the BNO board. Go here http://www.busnut.com/cgi-bin/bbs/search.cgi and do a search in subject lines for propane injection. 

[Lin]

I was very interested in doing propane injection and did speak to some that said it worked well for them.  It is said to work best with turbo, but still could have some benefit without it.  There are two reasons I never completed the project.  One is that I just got involved in doing other things.  The other is that I tried an experiment of shooting propane into the air intake.  With my engine idling at around 550 rpm, turning on the propane raised it about 50 rpm.  Although, that is roughly a 10% increase, I was a little disappointed.  I will probably experiment some more later.

[TomC]

Lin- remember that propane is a flammable gas-meaning it needs some sort of flame (in this case Diesel ignition) to fire it off.  When you introduced the propane at idle, the engine only went up 50rpm because the governor deactivated the injection, hence the propane wasn't firing off anymore.  A better test is to go up a steep hill with straight Diesel, then try it again with the propane activated and see the speed difference. Dual fuels have been used for years.  Up until a few years ago the Hyperion sewage treatment plant near L.A. airport used 10% Diesel and 90% sewage methane to run their big Worthington engines.  Cummins makes the ISX Cummins at 425hp as a dual fuel running Diesel as the spark plug for natural gas running.  Good Luck, TomC

[Jeremy]

I know when I worked for Perkins they built a lot of natural gas engines - usually sold for use in big gen sets I think

Jeremy

[Lin]

Tom,

You are certainly right that a better test would be under real conditions.  Maybe I was a bit lazy in doing it this way.  I am not sure that I understand what you mean that the injection was deactivated by the governor.  Does that mean the governor compensated for the added propane fuel by reducing the diesel fuel?  Please explain.  Thanks

[JohnEd]

Lin,

I think the answer must be yes.  Try setting the throt at any rpm and add propane.  That still isn't very good as the propane amt that is delivered has to vary with rpm.  I guess you could have the system deliver the gas ONLY when at Wide Open Throttle and I can't see any reason to have it injected as a "supplemental": fuel in any other circumstance.  One fixed jet, electric controlled Prop valve....and a switch on the dash.  What do you think?

John

[Lin]

As I understand it, you can use some sort of proportional valve that meters the propane according to the turbo.  Without turbo, you pick a compromise setting.  That would seem to mean that at lower rpm, you would be wasting some propane.  Further, some material I read said you do not get a lot of boost at high rpm's (again, at least without turbo).  Therefore you need to experiment to find the one that volume that gives you the best performance at mid range.  This then would just be controlled by a switch on the dash to flip on when you need boost, passing or climbing, and off when done.

Some have complained that this type of system is unsafe since you could forget to shut it off, you're in an accident or the engine shuts down for some other reason while propane is still being released, or your grandkids are playing at your dash and they turn the propane on.  We all know, of course, that these kinds of things never really happen, but you can build safeties in like connecting through the oil pressure telltale or a dead-man switch, etc.

[kyle4501]

Any fuel needs oxygen to burn, that oxygen usually comes from air. (Nitro-methane is an exception  )
adding propane is similar to adding more diesel, if there isn't enough air, it won't burn. Hence why it works better on turbocharged engines. In some cases, adding propane will cool the intake air charge & allow more air in the cylinder. I'd think that if the engine is smokin', adding more fuel won't help since you're already passing unburned fuel out the exhaust as evidenced by the smoke.

As to adding it to a 2 stroke, the throttle pedal advances the gov which controlls the rack based on engine rpm. As the propane is added, the rpms go up & the gov tries to maintain the rpm setting by closing the rack.


Optimum results seem to be found if something is understood before 'improvements' are designed . . . . .

Good luck in your quest.

[Lin]

Kyle,

Thanks for the info.  Some articles seem to claim that the improvement from adding propane is not just from adding burnable fuel, but from creating a better burn in the cylinder.  Therefore the increase in power would be from otherwise tossed fuel and should reduce black smoke.