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Propane enrichment for diesels
5

Propane enrichment for diesels

Propane enrichment for diesels

(OP)
I recently read about an after-market kit for electronic injection turbo-diesel automobiles which injected propane into the intake manifold.  This proportedly improved emmissions (gaseous and particulate), power, torque, and  fuel-economy.  The system ran on a maximum 15% propane (15% of caloric imput I presume).  Economy must have been computed as % ultimate efficencey of the combined fuels(?).  The kit seemed to rely on the electronic diesel-fuel management system to lean out the charge to achieve appropriate exhaust O2 levels.  Unfortunately, I've forgotten the name of the company and have had no success searching the internet...

I am interested in finding independant studies or documentation of this type of "dual-fuel" system and verifying its benefits.  Does anyone know of application of this system?

RE: Propane enrichment for diesels

4
Be warned that there are many "snake oil salesmen" on the market and the net!  I have participated in a great deal of research with dual fuel fumigation, both natural gas and propane and have seen my share.

Propane has an octane level and fuel sensitivity levels that prohibits it from being used in CI engines with a static compression ratio much over 16.5 to 1.

Very small amounts (minor fraction) of propane can provide GREAT amounts of power, and is the reason for the great prolification of these kits being marketed today.

I have seen some inside notes from one of these kit makers, and the way they calculated the percentage of use is that they use 1 gallon propane per 6.5 gallons of diesel (HUH?).  

Also, as of this posting, the EPA has not recognised the minor fraction fumigation as an alternative fuel, and no propane fumigation systems have EPA approval.

Several kit makers advertise a 30% gain in power with a 30% gain in fuel economy because the propane acts as a catalyst, increasing the efficiency of combustion, burning 90% of the diesel!

Something is missing, like my first class in Thermo 101.

The concept is a great idea, but the marketing folks are driving the engineers.  Propane in the diesel engine is not new, and a little bit is fine, but with almost all things, if a little bit is good, a lot is better.  One transmission manufacturer has declined warranty on some beta systems because of the power and torque load increases.


Regards.

RE: Propane enrichment for diesels

One additional comment, many of these kit manufacturers offer "drive adjustable power levels" which is a direct violation of the EPA anti-tampering law.  My last statement about a little bit being good and a lot being better is targeted at the driver selecting the level of usable power by a simple switch or cable-pull.

Somehow, when a driver becomes used to a particular vehicles performance criteria, they desire more.  Liken this to a beginning hot-rodder; first the big tires, then the carburetor, then the manifold, cam, headers, transmission, suspension, etc.

Once the driver becomes accustomed to the lower levels of fumigation, they feel they want more power and increase the amount of propane.  A driver adjustable system is probably the worst thing to happen here, since a little power is fine, but a lot of power can be damaging.

Regards.

RE: Propane enrichment for diesels

(OP)
Thanks, franzh, for your response, and sorry that it has taken me so long to respond.  I hope this reply gets to you, as I have some more questions.   "Minor fraction fumigation"  is a Phase i will now have to search on the net, but I still haven't found academic research about this subject, only "snake-oil", as you've said.

I am interested in quantified information about the moderate power boost and improved emmissions that could be available from minor fraction fumigation with LPG of CI deisel engines, as well as the possible minor benefit that cleaner operation might have on engine wear.  I would like to know what levels of fumigation  produce corresponding power output, and at what point this dual mixture begins to damage a "stock" engine.  I am particularly interested in the potential emmissions improvement.  Is this improvement in NOX and SO emissions and/or particulates?  What and to what extent?

If these are indeed advantages of minor fraction fumigation, I'm suprised that they seem to  be ignored  by the EPA.  If no propane systems are approved by the EPA, does this mean that these after-market kits are not street-legal?

If you can point me in teh direction of some existing, reputatable research, I would greatly appreciate it.  And again, thanks for the response.

RE: Propane enrichment for diesels

how is the propane metered?
when is it used- part power or full power conditions, or both?

since c-i engines always take a "full breath", the only time most of the air will get used (for burning fuel) is at full power. I don't know how much excess air is available at full power conditions in a typical c-i engine.
(more importantly, in "your" c-i engine.)

A c-i engine with turbo could be harder to evaluate- add more heat, the turbo will pump more air- limitations being the turbo performance, etc...

add propane to use some of the excess air, get more power, maybe help burn any of the (liquid)fuel that otherwise sneaks out unburned or partially burned (soot).

now- will the propane politely wait till the proper time, and not ignite/detonate early?
will it burn well/completely under part-power conditions?
will it steal some of the air that was needed to burn the liquid fuel, leading to more unburned/partially burned liquid fuel?

and, if you keep adding more fuel, will the turbo keep winding up, and overspeed/overload/frag your motor?

cheers
jay

RE: Propane enrichment for diesels

there's a thread about air-fuel rations in the Automotive Powertrain forum, looks like good info.
It appears the the "excess air" available varies wildly from one engine design to another...

RE: Propane enrichment for diesels

Yes, to most of the above.  CI engines are always "full breath" engines, which means that the same air mass is ingested for each stroke of the engine, regardless of the load setting (non-turbo).  The air volume increases with increased engine rpm (total volume per second), which can be used to meter the fuel.  Most of the currently available systems use a venturi with a weak signal to start the flow of fuel at some arbitrary point in its mid to upper load range.  Some of the marketed systems flow a fixed amount of fuel at boost which is not proportional to engine load or rpm.  Propane is not desired at low speeds.  There are a very few electronic injected systems currently in R&D, but show some promise.

The EPA states that a minor fraction fuel is less than 50% of the primary fuel.  Since it is difficult to get propane to operate in a CI engine at ratios above 15 to 20%, it is a minor fraction fuel.  The higher the static compression ratio of the engine, the lower the fraction of propane.  The higher the turbo boost, the lower the fraction.  Also remember that propane has a critical compression ratio somewhere around 12:1, at which it may begin its combustion process by compression generated heat, usually quite a bit before the diesel injection process.

One reason the EPA has not addressed these applications is that most of them are not initialized during the normal FTP-75 driving cycle, or if they are, it is only for a finite period.  Also, there is not established testing protocol since the engine is a dual fuel application (bi-fuel?).

Although the diesel engine only uses the amount of air needed to oxidize the fuel during the combustion process, (the excess air comment) when propane is metered in, the balance of the air is mixed with propane vapor, which also burns, but with the balance of the air.  Propane burns quicker and has a higher pressure spike than diesel.  You now have two distinctly different combustion processes taking place inside the combustion chamber, and a phenomenon called “colliding flame fronts”.

And lastly, the use of propane in a diesel engine can produce copious amounts of power, but also cause catastrophic engine damage.  OEM dealerships are now instructing their diesel technicians to look for signs of a recently removed fumigation system, and if they are found, an engine warranty is voided, often along with the transmission warranty!  Also, there is no significant amount of cost-per-mile savings when using a fumigated fuel, for reference: diesel has 150,000 btu’s per gallon, propane 91,500.  Its hard to justify the savings at 15% substitution.

By the way, I am a very staunch advocate for alternative fuels, propane in specific, but want it used responsibly.  I conduct research and training in gaseous fuels.

Best regards;

RE: Propane enrichment for diesels

i have been using andfitting fumigation type systems to ci engines for 18 months and have reports by qut marking greenhouse gas decreases and  fuel savings quantified at 8 cents per klm with no damage to engines i would love to here from you on this subject michaeleve@bigpond.com.au      cheers mike

RE: Propane enrichment for diesels

Mike:
In the US with most diesel engines (used by medium duty service in the 5.9 to 7.4 L region), the marketers of the dual fuel systems claim a 25% increase in power with the same percentage reduction in fuel usage.  Maybe with the diesel, but the LPG use increases.  I have done the dyno work, seen the engines, read the emissions, and drawn my own conclusions.  Locally, LPG fuel is about 15 cents higher per gallon than Diesel, at about 60% the energy value.

Diesel-LPG has its place, as a competent, quality installed system, without driver overrides, and minor fraction values, somewhere in the 10-12% range.

Very modern diesel engines with drive-by-wire and electronic injection, and aggressive computer controls, are hard to trick by dumping in another fuel.

Your comment about reducing greenhouse gasses is partially correct, the CO2 does drop, but the HC's, CO, and NOx increase.

Regards;

Franz

RE: Propane enrichment for diesels

Hi Franz, mikey's writing from O, where LPG is around 40% of the price of diesel, so the economic argument is a lot more compelling.

I'm a bit puzzled why the CO2 should drop, unless the CO rises in direct proportion.

Is the actual combustion efficiency improved by this LPG injection?



Cheers

Greg Locock

RE: Propane enrichment for diesels

Ahhh! The wonderful land of Ozzz.  That explains everything (grin {;=)

The last Diesel I tested emissions on showed about a 4% decrease in CO2 when about 5% lpg vapor was fed into the engine at 10% load (estimated to be a low load cruise).  When the air balance is altered with a gaseous fuel (and displaced too), the CO2 ratio changes too.  The lpg ignition point (CCR), pressure rise and drop, and flame travel speed are totally different than diesel.  These colliding flame fronts cause very unusual exhaust readings that often skew an amateurs rational’s, and reasoning’s.  Here in the US, NOx is the big bugger, and dumping fuel in raises the combustion temperature way past the Nox generation point.

The EPA has not authorized any emission testing protocols yet, mostly because any of the kits marketed here do not even energize at the levels offered on the FTP-75 or the new US-06, and I think on the Euro medium duty standard either.  Since the kits do not energize, the readings are no different than the OEM certified, thus meeting the EPA’s mandate that any system installed do not “effectively increase emissions over the baseline engine”.

ARRRGGHH!
Diesels do not operate at the nice tight Stoich window that gasoline/petrol engines do, so any emission calculations based on chemistry are pretty well a guessing game.

Help any?

Still haven’t figured why the cruise liner had the “thump” at cruise yet, but I think it may have to do with two screws in synchopation.  This ought to get the thread readers guessing!

Franz

RE: Propane enrichment for diesels

well I'm familiar with "screws" from watching Das Boot, and "syncopation" from HS band class...   

Are you suggesting that there was some sort of "beat" phenomena going on?  And btw, where the heck did this topic come from?

RE: Propane enrichment for diesels

Mr. Locock has an alter ego, a world authority on large ships.

Franz

RE: Propane enrichment for diesels

Woah thar, Mr Franz. I'm an interested amateur in the world of ships,whereas, for my sins, I'm a fully paid up noise and vibration engineer in the automotive field.


Cheers

Greg Locock

RE: Propane enrichment for diesels

Regardless, I find your knowledge on large ships extensive, and after all, if not for peer review, what other form of status is there?

(Now for my pat on the back!)
Franz

RE: Propane enrichment for diesels

He doesn't do a half bad job  on car stuff either.  He even does those funney little solar cars, too. ---And, he likes Minis, which puts him at the top of MY list.
Plus, the rest of the members, myself included, have placed him on top as 'el numero uno' by voting for his posts in the automotive forums.
Try not to let this all go to your head, mate, but I do post this with sincerity.


Rod

RE: Propane enrichment for diesels

Thanks for the thread on propane. Very informative.

I have a Ford DIT diesel and I see some of the owners chatting about it on other sites. I don't see any need to add something like this. The added cost of fuel, the additional components, appears to be more trouble then it would be worth. Seems to me the best way to up power in a diesel would be to add an intercooler change to a smaller turbine housing to compensate for pressure drop and watch for excessive EGTs.


phasers

RE: Propane enrichment for diesels

(OP)
Thanks for continuing to feed me info on this Propane/diesel thang...interesting beat/synchpation crypto-ditty too.  Guess you guys know each other....

It sounds like moderate fumigation (5-12%) offers some increased power and a linear increase in engine wear (is there a decreased production of particulates that might benifit engine wear? Straight propane engines don't pollute their oil).

Sounds like NOX production might be increased by Propane, but how significantly at low propane %?  It seems to me that if you have carbon in your fuel you are going to get the corresponding amount of CO2 -- in fact, I would guess that the best way to exhaust Carbon would be at Maximum CO2 levels, else you get CO or soot, which is a big pollution factor in diesels; which brings me to third:

Emissions:
Their are two emissions issues with diesels: greenhouse/acid rain and human health.
I don't know what the CO2/CO/NOX/sulfur emissions for modern diesels are and what the U.S. and European requirements are for these (Reader: Please steer me to web-site, lay-digestible info on these topics). How do the emission of diesels compare to those of gasoline engines, underload,  and after 100K miles? Its my impression that diesels are better on gaseous emissons and bad on particulates.  I believe that damage to the humans lungs is less of a "sin" than damage to the larger ecosystem. Aren't particulates unburned carbon?

As far as why:
being able to use 10% of an alternative fuel gives one a different fuel-market to exploit, as noted about.  Minor enrichment takes little modification and is there to take or leave.  Propane is still not a fuel that it would be easy to drive accross country on; This dual-fuel option would promote and exploit the expansion of the automotive propane fuel-delivery infrastruction without being wedded to it.  On-board propane could be used to great advantage in other ways on certain types of vehicles:  Heaters, generators, refrigeration.  Imagine that you had a small propane engine in your engine bay that could drive the engine mounted compressor and generator  through clutch engagement or a couple of opposed freewheels (hell! If you wanted you could simply detach these place them elsewhere in your vehicle to solve other auto design issues.)  small propane engines start, run and maintain more easily than liquid fuel models, and produce only  H20 and CO2.  Think of it as extended battery maintence  and backup.  You could also take the  load of these parasitic devices in times when you wanted full HP to the drivetrain.  Thirdly,  as a further refinement of systems like VW's (euro-only!) Eco-diesel concept, you could shut the diesel down at idle and run you A/C and creep in bumper-to -bumper traffic in the propane engine alone.  You could also use it as an alternate starter, a handy thing on a hard-cranking diesel. Am I sounding like a crank?  Talk to me....

RE: Propane enrichment for diesels

A 'trolling motor' for a   VW ?   Hmmmmmmmmmm.


Rod

RE: Propane enrichment for diesels

Sportster:
Great comments.  The single biggest problem with a vehicle operating on two fuels is training the driver to fill with both, or either.  For years, large manufacturers have discovered that starting an engine on a gaseous fuel is easier on the engine, less polluting, faster catalyst warm up, longer lasting engine since no liquid fuel wash down, etc.  The problem was training the driver to find and fill two fuel systems, and the transition period when the gaseous fuel stopped, and the liquid fuel began.

Visualize this, the engine starts on propane and runs for about 1 minute.  Total fuel consumed about ½ pint.  But during this period, the driver would back out of a driveway and begin to accelerate on a city street, just about the time the engine switches fuel.  How to make the transition smooth without bucking or backfiring is the problem.  The advantage is that the engine is starting on a dry fuel, no cylinder washdown, good fuel distribution, a rich enough mixture to preheat the cat.  The HC’s and CO are handled by the rapidly heating cat and since there is minimal particulate production with a rich gaseous fuel mixture, there is almost no contamination of the oil.

Also, running two fuels brings into play the engine management system, how do you optimize two different and separate fuel systems?  OEM’s have had a difficult enough time with one, much less two.

Your comments on the diesel emissions are well placed.  Consider this:  Diesel engines are unthrottled and inherently produce more NOx because of excess air.  The addition of propane decreases the air BUT increases the combustion temperature and pressure, resulting in increased NOx and HC’s, but at slightly decreased PM (more fuel, less diesel, higher temps, equal power at a lower throttle setting.)

There is a well-established propane distribution network in the US, and in most of the world too.  Take all the other alternative fuels vehicles worldwide, then quadruple the amount, and propane vehicles are still more than that too!  It IS possible to drive coast to coast on a pure propane vehicle, I have done so, with a little planning.  Remember the Olds diesel produced in the late 1970’s?   In the owners glovebox was a diesel distribution outlet guide showing car friendly diesel outlets.  The same is possible with propane.

Final parting thought, remember that diesel fuel has a higher caloric value by weight than propane.  It takes 1.6 times the amount of propane to produce the same power as diesel.

Regards;
Franz

RE: Propane enrichment for diesels

All interesting stuff. LPG availability no problem in UK, though mileages are a tad smaller! Italian LPG bits are cheap and every man and his dog are converting petrol vehicles ( no legislation at present!)
            Diesel fumigation is newish here, and I have been playing with a 160 bhp cummins B series using vapouriser,power valve and simple 10mm pipe mixer in turbo intake, pressure switch bringing gas on at 3psi.Setting is finger in the air stuff, and suggestions would be appreciated.I have been adjusting the inline power valve on the move, while turning the gas on and off, and monitoring the sudden increase in boost pressure. A point is reached where the pressure rise peaks for increasing amounts of gas, eg  5psi at 70mph --- 9psi + acceleration.I am assuming this represents max. power but at what % lpg I have no idea. I would also have thought that the injection pumps boost enrichment should be reduced with gas applied,but not sure about main fuel adjustment Any thoughts? I know some outfits reduce main diesel adjustment to prevent engine and transmission going bang. I am monitoring transfer box temperatures, and they soon start to climb with gas on!
    I have toyed with the idea of a motorised power valve ( lambda control type) but  no clue as to what to monitor to control it, excess lpg in exhaust?,  use electronics to continually maximise boost pressure?
           The vehicle is a 6x6, 5 tonnes camper, I have built based on a Land Rover 101 ex mil. tractor unit, and power is what I am after. In the UK this engine is usuallly 130 or 160bhp and 210s are not that common
   Now I am rambling,need to get out more! Must go
           Regards
                     BigH

RE: Propane enrichment for diesels

Another problem I see with propane fumigation is in trying to increase power output in the modern electronically controlled diesel engines.  Such engines control output power electronically.  Caterpillar, for example, “Sells Horsepower”.  What they mean by this is they will sell you a 3126B engine rated at 860 lbs of torque and 200 horsepower for thousands of dollars less than a 3126B engine rated at 860 lbs of torque and 300 horsepower.  Same exact engine, just different programming in its computer, which limits its output power.  Later on if you decide that you want a higher horsepower engine, you pay Caterpillar a few thousand dollars and they will “Flash” the computer chip to turn it into a 225, 250, 275, or 300 horsepower engine.  More horsepower = more dollars for the upgrade.  It seems that if you were to try to increase power output on such an engine by introducing propane fumigation, the computer chip would merely command a corresponding reduction in diesel fuel flow to keep the maximum horsepower from exceeding what it is programmed to deliver.  Correct me if I am wrong about this.  Torque is another matter, and I am not sure how the computer would control that.

RE: Propane enrichment for diesels

Its easy to dump a lot of fuel into a diesel engine, even an electronically controlled one.  The onboard computer has no way of knowing how much power the engine is producing, as long as the diesel profile is not altered, and the RPM is still within governing limits.  When the governed RPM is reached, the electronic control system simply backs off on the diesel and allows the other fuel to take over.  As long as the amount of fuel and RPM control are within the tolerances, the computer doesnt know (or care).

The problem is as I mentioned earlier, a little power is fine, but soon, the driver wants a LOT more, and its available often by a twist of the screw!  This is dangerous and can lead to EXPENSIVE non-warrantable repairs.  The TV shows and on-line advertisements do not disclose the possible side effect, only that a BUNCH of power is available.

Lastly, NONE of the web-advertised LPG-Diesel fumigation kits are EPA or CARB approved, therefore illegal to install or sell commercially.  Treat it the same as an aftermarket camshaft or intake system on a gasoline (petrol) product.  It was not emission tested or certified by the manufacturer, therefore, not permissable to install on over the road vehicles, your own or for a consumer.

Caveat Emptor (there have been more than a few dissatisfied owners so far!)

Franz

RE: Propane enrichment for diesels

"The onboard computer has no way of knowing how much power the engine is producing, as long as the diesel profile is not altered, and the RPM is still within governing limits."

Just thought I'd let you know that at last there is a viable concept to cheaply and easily measure shaft torque, from which of course you can get power by combining with RPM.  

It's not hokey, it's not snake oil, it can be retrofitted without altering a drive shaft, and it has the potential of being inexpensive.  It has been patented overseas and a U.S. patent applied for via the patent cooperation treaty.

If interested, let me know.

RE: Propane enrichment for diesels

This subject seems to be going a bit cold now with no responses for some time. I thought that I would try to get it going again by telling you guys that I have been working on dual fuel development for about a year now and have 15 R&D vehicles out on the road. The initial finding are very encouraging. We have fitted an electronically controlled vapour injection system to these vehicles and the first thing that you notice is the terrific power increase. We are having to "calm" them down. They are also showing fuel savings and are at present being tested for emissions. We have one van that is out with a delivery company and has covered 65000km since September and is going as well as day one. I hope to have it in soon for an engine strip down to check things over. I will keep you posted.

RE: Propane enrichment for diesels

well hi people i have been fitting and developing a fumigation system for diesel for near on two years now with some great results.emmission testing is being carried out by qut in queensland.we have over 50 trucks on the system as of today with most returning greater driverability and fuel savings up to 7cents a klm.increased klms between oil changes and proven by oil tests every 5000k.we use propane as fuel.we have been working with australian epa and state government.our web site is under going a face lift and will be up and going soon complete with report copies photos ect.emmission test have shown reductions in greenhouse gases.i look forward to your input.

cheers mike                 michaeleve@bigpond.com.au

RE: Propane enrichment for diesels

I'm curious if "Sportster" is really trying to build a diesel powered Harley and where the heck he's gonna hide the propane bottle!!
I did LNG (natual gas) powered golf car conversions in a former life - the Major pain was finding room for the gas cylinders and the safety issues. I'm not sure I'd want to be cruising down the highway at 75 with a big propane tank strapped in the bed of the Dodge Ram.
Of course it would be handy at the Tailgate parties....

Keep the wheels on the ground
Bob
showshine@aol.com

RE: Propane enrichment for diesels

Just when we thought this thread was dead, it surfaces!

The propane tank in the bed of a truck is possibly the strongest item on the vehicle, excluding the engine block and possibly the frame members.  The have an excellent safety history, far greater than either diesel or gasoline.

The propane tank is far stronger than the LNG dewar, and safer than 3600 psi NGV-2 cylinders.

In its place, propane can be excellent benefit to diesel engines, but with the proper use and ratios.

Franz

RE: Propane enrichment for diesels

hi,
    I am wanting to assemble a toyota 22r engine to run on propane only..

does anyone know what compression ratio would be suitable???

thank you

bikejeremy

RE: Propane enrichment for diesels

Interesting thread I just like to say my machine shop has built engines to run propane for 25 years as I live in B.C. Canada and every cab and most gas powered truck have been converted to run dual fuel or just propane. Propane is 29cents a litre and gas is 70+ I once bought propane for 1 cent a litre during a price war. 213 litres  for $2.13 What a deal...
 A few years back The factories got into act with propane powered cars and trucks.   Dodge built a liquid injected 360. They heated the injectors to prevent them from freezing. Man talk about throttle responds, it was unreal.
  I've turbo charged, supercharged, added nitrous, etc Added it to diesels. What I've found is its hard on pistons lands and rings especially if you get to much compression, I prefer no more than 9-1 on heavy truck and no more than 11-1 on light cars. Although I have turboed trucks with 9 to 1 and 20 pounds boost. I've also done 13-1 N.A.
They were high dollar custom stuff. It just not worth the grief to push the compression ratio to 12-1
 Anyway its hard on exhuast valves and seats, Prefers cams with smaller duration than gas, likes lots of timing on lower compression engines,it will lug down low like a diesel
When added to big diesels,if you get carried away it breaks drivetrains parts like transmissions, rear ends,etc from the increase in power. As a side benefit to propane the oil stays clean so the interanal parts don't wear.   

RE: Propane enrichment for diesels

Thanks for the star guys, much appreciated.

One item that seems to be overlooked is that when a gaseous fueled engine goes lean, the exhaust temps also LOWER, and when the mixture goes rich, the temps RAISE.  There is no evaporative effect with the gaseous fuel.  I ran one 6.0 liter engine to L=1.9 and the exhaust temps were around 800 deg F!  This was at 3000 rpm, 30 psi turbo boost, and about 290 bhp.  Bringing the L ratio closer to 1.0 raised the power levels, but also the exhaust temps, and the NOx went through the roof!

Lean burn and NOx control are also different with gaseous fuels.  Going a tad rich (A/F .97) will lower NOx, but will also raise them again due to exhaust temps).

It takes a different mental picture of the combustion process when operating with gaseous fuels than with liquid fuels.

Its also kind of addicting!  I am sure RacerRick will agree!

Regards

Franz

RE: Propane enrichment for diesels

Franzh Seeing you have done tests with propane. What do you think about combustion chamber shapes?
  Is it possible to have to much quench turbulance in the chamber?
 It seems to decrease the octane of the fuel if you do. I've found you need some but not to much.
 It seems like the reaction rate of propane increases at higher piston speeds due to increased turbulance within the chamber which can cause some high quench chambers to detonate even though they have the same CR as a more open style chamber.
 In other words the more open the chamber to a point the less likely it will detonate at higher rpms. Is that generalization what you have found?
 It reacts, kind of opposite to gasoline

RE: Propane enrichment for diesels

Hmmm.
I have personally liked open chambers with unshrouded valves.  Seems like the trend with gasoline is to small kidney shaped chambers to promote fast burning.

I tend to agree with all of your comments.  One thing additional is that Propane tends to have low fuel sensitivity compared to Natural Gas, thus more critical as to compression and ignition timing.

Been a while since I have seen the high speed photography with a propane combustion  front, but at some of the pistion travel speeds in the 6000 rpm range, the flame held together equally as well if not better than liquid fuel applications.

I would like to see a direct comparison on equal engines between open vs closed chambers, possible one engine with two different styles, one for each bank.  This might shed some light.  Research funding anyone?

Franz

RE: Propane enrichment for diesels

Hi,
I just came across this thread. I'm doing some research on propane(lpg) fumigation of diesel engines. I intend fumigating a pair of normally aspirated Perkins 4-236c.i. direct injection diesel engines presently rated at 84bhp @2800rpm. These are on a marine installation and run almost exclusively on cruise and full throttle speeds.
To what extent would a fumigation system be beneficial on such an installation?
Look forward to comments from you all out there.

Thanks and regards
Autogasmarine

RE: Propane enrichment for diesels

Re-read this thread, no sense in beating a dead horse.
Franz

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RE: Propane enrichment for diesels

The thread is an interesting read and should be made into a FAQ.  Great input Franz.  Thanks for relating your experience in understandable language.

I was introduced to the fumigation topic 20 or so years ago in the heavy duty trucking industry.  There were several people pushing it.  That was before the days of electronic engines and the fine control that they offer.

As a ME that had survived Thermo 101, I saw potential, but I also saw some of the drawbacks mentioned here.  Since I had a passing interest in the topic, and an associate who had an industry connection, I inquired about the progress/status of the concept.  The only answer I got was that fumigated HD diesel engines had suffered an inordinate amount of stretched head bolts, and that it was a no-go.

This would go to verification of some of the problems mentioned herein.

My contribution to a very old, but none the less interesting thread.

I think your third star is long overdue, Franz.

rmw

RE: Propane enrichment for diesels

Thanks, again, much appreciated!

There is an FAQ on propane, been there a couple of weeks now.

Ages ago, I heard of truckers using Cummins Big Cam engines, and others with Detroit 671's with a propane tank behind the cab, a hose and barbeque regulator, with a ball valve in the cab, dumping propane vapor directly in the air intake.  Reportedly, it would allow for hill climbs without dropping into the low split box (old over the road trucks would have dual boxes with twin shifters).  Stretched head bolts, cracked heads, blown pistons and sleeves, blown exhaust manifolds and early turbo's, burned underhood rubber parts from glowing exhaust manifolds, were all stories from old truckers I've heard.
Franz

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RE: Propane enrichment for diesels

I'm surprised they didn't blow the intake apart as well - any flame at all in the header and you've got a bomb. A pressure relief flap in the intake is a wise investment.

Cheers

Greg Locock

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RE: Propane enrichment for diesels

I saw the FAQ on propane, but was suggesting one for propane fumigation per se.

The big rig systems I was mentioning were not just jury rigs, they were store bought systems.  If I think long enough, I will remember the name of the company in the Los Angeles area that was a big promoter.  I visited their place, but didn't have the $$ to do it to my pickup.  Later I just added a turbo, and had that 6.9 Ford IDI diesel doing about it could anyway.

rmw

RE: Propane enrichment for diesels

The name Red Hat or Red Top rings a bell.  I'll work on a FAQ on diesel fumigation when I return from an assignment and get some spare (HAH!) time.  Right now, my project Mustang is taking most of my left over time.
Franz

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RE: Propane enrichment for diesels

For what its worth, I added a section to the FAQ at the top of this column, on dual fuel with LPG.
Franz

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