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Direct Liquid Propane Injection?

Direct Liquid Propane Injection?

Direct Liquid Propane Injection?

I am currently searching for an alternative fuel to convert my truck.  I have settled on Propane.  But in my research i found that the closer the injector is to the combustion chamber the more power and efficiency are acheived.

I was curious if anyone has come across a Direct Injection Propane System, in liquid form.  I can only find systems that use vapor and another that uses liquid but is in the intake.

Any info is appreciated,



RE: Direct Liquid Propane Injection?

My former employer used direct injection LPG systems on forklifts so I know it is possible, but unfortunately I don't know who supplied the injectors. ISZ

RE: Direct Liquid Propane Injection?

Keeping my ear to the industry (big ear, little industry) there are no direct (into the cylinder) injected liquid injections in production form on propane.  There ARE propane vapor injection systems from almost all major OEM lift truck manufacturers, but I am not aware of any OEM Liquid Phase Propane Injection systems on lift trucks.
Mogas has experimented on same and CleanFuelUSA has an OEM upfit for a few specific OEM platforms, not for the aftermarket installer.
In Europe, Vialle and ICOM are the two major liquid injection suppliers, but these too are port injected, NOT direct injected.
I saw one lab engine on direct injection but it is years away from any production hopeful capabilities.


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RE: Direct Liquid Propane Injection?

Somehow the OP's mention of the word "Direct" completely escaped me.  As Franz said, there are no aftermarket retrofit systems for direct liquid propane injection.  All systems are port injected.

The amount of development and eventual complexity of a true DI system is simply way over the heads and costs of what could be realised outside of an OEM or a major engine development consultancy (e.g. Ricardo, AVL, FEV, Mahle (formerly Cosworth Engineering), Lotus Engineering, etc.), and the costs of implementing such a system as an aftermarket "kit" would be prohibitive.

Liquid propane injection has clear advantages over gaseous; but what is your motivation for wanting to do DI (I'm not saying there aren't any advantages of DI here).

You might also contact Cummins-Westport.  While they don't work with propane, they do have a system that directly injects natural gas into the combustion chamber, and ignited with a Diesel pilot injection.   

RE: Direct Liquid Propane Injection?

I assumed you meant port injected as opposed to a carb.


RE: Direct Liquid Propane Injection?

After re-reading the original post, I think he was indeed stating direct cylinder injection.

Besides no aftermarket systems, there are no OEM ones either.  Pumping propane to pressures needed for DI use introduces other issues as well, including diesel like fuel pumps (not modified diesel pumps though), and a host of other technical problems.  New Thread?


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RE: Direct Liquid Propane Injection?

Pricej20 did you actually mean direct injection (into the cylinder) or do you just mean port injection?
I've never heard of direct injection propane, hence why i'm asking.  Would you "settle" for liquid port injection?

Side question to the other members - can direct diesel injectors be used for liquid propane injection?  Since direct diesel injectors could handle the high pressure?


RE: Direct Liquid Propane Injection?

Mazada has the only spark engine with direct fuel injection. Their 2.3 liter in the Mazdaspeed 3 and 6.

RE: Direct Liquid Propane Injection?


Pump lubrication is the usual problem when injecting other fluids with a diesel pump.


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RE: Direct Liquid Propane Injection?


That is so wrong.  BMW, VW, Audi, Lexus, several others and even GM now have gasoline direct injection in production vehicles.

RE: Direct Liquid Propane Injection?

dgallup wins Again!  Every automaker will offer DI in the not too distant future.

As for LPDI, yes it has been done.  For the typical applications it is of no economic value because of the low potential volumes.  From a techincal perspective, it works well sort of..  The problem is with hot fuel handling.
As for converting a truck, forget DI.  Liquid phase port injection offers improved charge density and longer valve life and more but the problem aint the technology, its the WWII era fuel quality standards that the LPG industry had barely improved to date.  Before catalytic converters were on vehicles, gasolines were offerred with detergents and formulations were blended to reduce common problems.  LPG on the other hand is sold as is where is with standards that DO NOT accomodate the clean up or keep clean requirements of precision orifice liquid fuel injectors.  For now it is safer to stick with vapor injection, when the lpg industry is forced to produce motorfuel that is compatible with the hightened requirements of liquid phase injection then the it will be less costly (warranty) for upfitters to use lpi.  
If you are converting to lpg as a hobby and to tinker then port injected lpi is fun to mess with.  
Good luck.  

RE: Direct Liquid Propane Injection?

I suppose that this is off topic, I am new here, been reading and searching for information regarding liquid propane injection systems. however the other threads that I found was about 3 years old that was even close to this subject.   

I ran accross this company who is offering a "solution". www.technocarb.com.

 Turbo, you seem to be the go to guy.  Your thoughts?   

RE: Direct Liquid Propane Injection?

I never saw a carburetor I liked.  I do not know what they have now but in the past I was unimpressed with their stuff.
Unless it can meet the same rigorous operational and pollution control requirements as an oem gasoline system it is not something I would endorse.  No matter how well any mfg engineers a system, the lack of Real, and I mean REAL motor fuel standards that include detergents to remove deposits will prevent conformance with epa/carb regs.  The better systems out there are more vulnerable to failure due to sulphur and olefin deposits.  These same elements are not a problem for fuel injectors is a few compounds are added to the fuel.

RE: Direct Liquid Propane Injection?

Their current solution appears to be a ECU controlled gaseous sequential port injection system utilizing a shared "vaporizor" for lack of a better description.  So, if my observation is true, then this is not a real Liquid-PG injected solution.

this the PDF product description:

RE: Direct Liquid Propane Injection?

The best technology out there st this unction is oem and it is only available from the oem as a factory fitted system.  That is the only economically justifiable way to go in my opinion.  The oem warranties it and the technology has the benefit of real durability validation where the kit is a modification at a higher risk.

RE: Direct Liquid Propane Injection?

OEM solutions would be nice.  I am looking to "tinker" with LPG/Turbo and as you have pointed out previously there basically are no OEM outlets for the hardware to make it happen.  What I am left with is trying to find/assemble/create from what is available or what I can obtain and modify, given the limitations presented by the fuel quality I wonder if it is worth my time as others have been down this path with mixed success.

ROUSH just released the OEM LPG F150 as a $10k option.....

RE: Direct Liquid Propane Injection?

Buy the Roush upfitted F150.  It is state of the art.  Nothing out there comes close.  It is an improved version of the same basic fuel delivery strategy that was pioneered by Vialle/Siemens and Chrysler Canada in the 90's.  As stated earlier, LPG is not widely available with motor fuel additives so you have to add your own.  In the past I assisted Bell Additives.  They offer an lpg specific additive that I tested along with other stuff from Ethyl and Lubrizol among others while working with cng/lpg at Siemens (now Continental).  Bell Additives (now Bell Performance) formulated an lpg additive at my suggestion to best accomodate liquid injected lpg that replaced the oil base and leaves no residue and has other properties to protect seals and prevent known problems with leakage.  The new stuff was tested on every type of material found in the siemens injector as well as the GFI compuvalve.  GFI  participated in our discussions that led to the revised additive with guidance from a respected retired Chevron chemist who knows his stuff.  Not sure if the reformulated lp additive is a stock item..  good luck, Turbo Cohen

RE: Direct Liquid Propane Injection?

Vialle makes what they call their "LPi " system. It injects liquid LPG (and gasoline, if dual fuel) into the intake manifold close to the intake valve. They have a detailed listing of makes and models of vehicles they make the systems for.


Orbital recently bought BASF , so now is in bed with Vialle. Orbital/Vialle has contracts to supply Ford Au. with the Vialle systems. I suspect Orbital will also adapt their Direct Injection technology to the Vialle system.


RE: Direct Liquid Propane Injection?

Motorbyte LLC demonstrated "Anyfuel" capability a decade ago :)  The work was patented and assigned to Siemens.  Coincidentally, the work was demonstrated using the same basic bottom feed injector that Orbital is/was using for their innovative low pressure gasoline/air DI.  Gasoline, lpg, alcohol and some unconventional liquids were injected through a common system at s school we sponsored for one of the sae research competitions.  An hpdi system would offer some advantages.

RE: Direct Liquid Propane Injection?

The Schwans company owns a proprietary liquid propane injection system that is used on all their delivery trucks.
They were going to market the system, and even had a website, but it was never finished and has now disappeared. I guess they thought the better of it.
An automotive engineer named David Bennett patented the system in 1998 and Schwans bought him out, patent, manufacturing operation and all. You can look at his drawings at Patents on line.
Since LPG has a slightly lower HHV than gasoline and with a gaseous propane carbureted system so much of the air available for combustion is displaced by the fuel, carbureted propane systems were considerably less efficient than gasoline systems. Turbocharging was about the only way to get the lost efficiency back.
The liquid injection system has nozzles that expel the propane right above the intake valve. At speed, a considerable amount of liquid propane makes it into the combustion chamber. The phase change occuring within the combustion chamber cools the air/fuel charge and contributes to the overall compression ratio. This system is supposed to be more efficient than gasoline.

RE: Direct Liquid Propane Injection?

"Efficiency" is probably not the term you meant to use.  I believe you are trying to describe the power loss caused by displacement of air by a gaseous fuel.
Efficiency of an Otto cycle engine is less a function of the fuel itself than many other parameters, which can and should be optimized for a particular fuel.

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