Fuel injectors that can tolerate 120psi 3

[obanion]

Anyone know if there are any fuel injectors I can purchase or obtain that can go to 120psi without exploding? I'd like liquid propane delivery, but normal gasoline injectors will just explode at the nessasary pressures. Diesel injectors may be my last resort if I can't find anything else.

I have seen the tech reports for the Multec Bottom Feed Methanol injectors, claiming pressures up to 1000KPA (130psi gauge pressure). They would be perfect, except.....you can't buy them. I have been told they only come packaged with race engines, Delphi doesn't sell them.

http://www.delphi.com/pdf/racing/multecbottomfeed_meth.pdf

 

[Nothegger]

I am considering a project with hydrogen injected ICE. One of the problems is injectors. I think the best way is hydrogen direct injection, it yields best efficiency. Now I'm looking for hi pressure injectors that could inject hydrogen. The diesel injectors seem like the only option, although the problem is the hydrogen is a dry fuel, and there is no sufficient lubrication. Another idea is to inject liquid hydrogen to reduce combustion chamber temperature and prevent detonation.

 

[franzh]

Uh, before you jump in and get over your head, several years ago I was part of an investigational team working with Natural Gas/Diesel on a locomotive engine. What we found the biggest problem to be was providing lubrication to the NG injector and it suffered the highest failure. This was a DI engine. Direct injection in a SI engine will encounter the same problems, only diesel fuel will not be the pilot ignition source.
Also, you really should look at the physical properties of L-H2, storage, temperature, thermal shock, etc. Almost all metals react violently to the thermal shocks of being exposed to the incredibly low temperatures of L-H2 on one side and combustion temperatures on the other.
Go with port injection H2, many Natural Gas products work. Also, investigate Hydrogen imbrittlement, it will open some eyes on material selection.
Lastly, H2 is not especially efficient in comparison to other fuels. It is currentlty the sweetheart fuel of many politicians which gets it more than its share of "air-time". There is a thread somewhere in this forum that deals with H2 issues.
Franz

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Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[unclesyd]

There was a show on The Speed Channel (US) recently where they installed an injector for Propane (liquid) into the manifold of a V8 diesel engine. The system came as a bolt on kit. I wasn't paying much attention until they claimed (?125?) dynamometer increase in horsepower.
If I recall correctly they mentioned they were spraying liquid Propane.

 

[turkeyokato]

Here is the link to the replies I got from injection companies.
Hope it helps.
Joe.

http://p206.ezboard.com/fmoparmarketfrm27.showMessage?topicID=61.topic

 

[Nothegger]

Yes, I understand the implications, it will take a lot of experimenting to find a best working solution.
The efficiency depends on several factors like CR, mixture and injection metod. If all factors are considered it can result in efficiency beyond that of gasolne. Also, fact that you can regulate output by changing mixture is rather attractive. In this case I'm more interested in output, not emissions.
As for storage, really efficient one is still to be developed. 10000 psi tanks were introduced recently, but I see it as temporary solution. Best storage would probably be based on carbon nanotubes, it is very promising technology.
Thermal shock is one of the big problems, and I'm aware that special materials will be required. There are few things that might help, MMC alloys, ceramic coatings, etc.
This is a long-term project, and I'm still in a phase of puting the theory together ang gathering information, so, every insight into the matter is appreciated.

 

[Aero55]

turkeyokato, thanks for the link. I had pretty much the same information as you,

Franzh, you seem to have a good background in this area, would you know of any liquid phase LPG injectors or automotive injectors that would work at the necessary high pressures to maintain the lpg as a liquid? I have read some reports of experimental systems running with Deka II injectors, but not really much else. I am excluding injectors such as the Bi-phase or Liquiphase type systems, where the entire fueling system is unique and has completely different function from a normal fuel injector.

I also came across a website somewhere that says the mitsubishi GDI injectors mentioned above would die pretty quickly when used with LPG.

 

[yoyo133]

Have you looked at the injectors from Evinrude and/or Yamaha direct injection 2-stroke outboard motors?

 

[unclesyd]

You might get some info from these people. You might have to goto Austin and front a couple of beers.

http://www.me.utexas.edu/~sae/37chevy.html

I have to take back my previous post as the system that was installed was a vapor system.

 

[mitsuko]

Gaseous injection is quite easy .
Liquid injection isnt .

There's one manufacturer in Holland .
Don't email them , they don't bother to answer .
But they have a liquid phase multipoint setup .

It uses an pump inside the tank that deliveres the lpg
at a pressure of about 16 Bar .
Never try to use tank pressure , it won't work .
You'll be injecting a two stage fluid , and there's no relationship between pulsewith and injected amount of fuel . The pumps are fragile , and often require rebuild .
This is because the lpg isn't lubricating , and the bearings wear quickly .

The lpg injectors are extremely low impedance , and require
a special peak and hold driver to control them . Lm1949 based . They are also huge compared to std bosch injectors . Manifold clearance is often a problem .

I'm gonna use this setup someday on a turbocharged audi I5 . Abt 260 Hp . I'll use megasquirt as an ecu .

The biggest advantage of liquid injection is that it cooles the air charge , and if you also have an adapted ignition timing , it produces more HP than gasoline .


Pat

 

[Aero55]

I have looked at both of those injectors previously.

Evinrude's injectors are Ficht type injectors that produce the high pressure at the injector from a rapid solenoid hammering the fuel to high pressures. I don't see this working for LPG, because the high pressure needs to be maintained through out the system, to prevent vapor lock. It would be interesting to see if the Ficht type injector could compress a vapour LPG to liquid, but that is something I wouldn't have the resources to investigate.

The Yamaha HPDI injection system seems adequate at pressure, but my research has indicated that they do seem to have some durability issues with lubrication. This could be amplified when using LPG.

I remember a few years ago I was investigating a HPDI system, and that gasoline fuel pumps to operate at such a high pressure were impossible to find/get hands on. Diesel pumps would run at high pressure, but the fuel would lubricate the pumps. So this would create a lubricity scale something like this, is this correct?:
Diesel fuel > Gasoline > LPG

Mitsuko, by two stage fuel, do you mean two phase (ie. mixture of liquid and gaseous fuel? At 16 bar throughout the system, the LPG should stay in the liquid phase. I could see the dual phase LPG occuring at lower pressures such as 1.5-2.0 bar, but not at such a high pressure.

 

[Aero55]

I have looked at both those injectors.
The evinrude injectors use Ficht injection, which uses a solenoid to rapidly hammer the fuel, which generates the high pressure at the injector. This would not work when trying to maintain a high pressure throughout the system to maintain LPG as a liquid. It would be interesting to see if the ficht injector could compress vapour LPG into liquid form, but that would just add complexity to the system.

The yamaha HPDI injector system seems alright, although I did read a report or two about injectors failing due to lubrication issues. I came upon this system a few years ago looking for a high pressure gasoline fuel pump. However, obtaining any high pressure fuel pump for experimenting was impossible. Using diesel pumps was not a valid solution either. For lubricity of fuels it would then go something like this:
Diesel > Gasoline > LPG liquid > LPG vapour
I could see these injetors/fuel system struggling under LPG, if this is correct.

Mitsuko,
by two stage fuel, do you mean two phase fuel (i.e. both liquid and gaseous states). I would expect seeing this at lower pressures such as 2bar, but not at something as excessive as 16bar. What temperatures are you running at to cause that?

I know it isn't easy, but it still might be worth attempting.

 

[mitsuko]

Yes i mean two phase fuel .
Sorry , I'm dutch speaking .

You'll only have two stage liquid if you use tank pressure at the injectors . You know that at a given temperature ,
each liquid has a matching vapour pressure .
There's no way telling what the amont of liquid an vapour will be at the injectors , if you feed them using the
"natural" pressure of the tank .

With the pump at 16 bar , you're absolutely sure to have liquid only . Vapour cannot exist anymore .
Then injector pulsewith will have a correct relationship to the injected mass of fuel .

Thesame happens with gaseous injection .
The liquid is heated above 80° C by engine coolant ,
vaporised and reduced in pressure to ambient.
This makes sure no liquid can exist anymore , and you inject once again a single phase fuel .
Still the pulsewith needs to be corrected for both temparture and pressure .
PV=nrT . Pulsewith = V , nr is a constant .
T an P need to be taken in account to calculate the correct
mass of fuel .


Fascinating stuff

Pat

 

[vilcarlo]

There's a bi-fuel FIAT Multipla normally sold in the Italian Market, which is equipped with two completely separated injection systems (also two divided ECUs). The LPG liquid-phase injection system is sold by Metatron (formerly a joint venture between FIAT, Tartarini Auto and others, now a separate firm) ... we at the University just both a comlpete Metatrono LPPI injection system to set up an experimental activity on the fuel spray (which tends to form ice particles at the inlet manifold obstructing the injector and prejudging partially mixture control). The injectro rail alone costed 220 € (the 4 injectors and the rail), the complete system (without the ECU: tank, manifolds, injector rail) was 980 € (for educational purposes). The system is not equipped with a pressure regulator, so it still has some problems in controlling air fuel ratio, expecially at high engine speed, when injections at different injectors overlap.

 

[optimum]

What if you used a nitrous oxide kit and ran propane through it? The solenoids could be triggered off of a crank or dist p/u. It would be crude but might work

 

[franzh]

These solenoids do not have enough sensitivity or fine action control, and cannot cycle fast enough to serve as an injector.
Franz

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[unclesyd]

Checkout the last post by optimum:

thread71-108825

 

[fueldoc]

These injectors are designed for gaseous LP, NG and H2. Look at

http://www.qtww.com

May be the answer to problem. Have used on liquid with good results. The main issue is thermal, not pressure, as these can handle many bar., FD

 

[franzh]

Just a very strongly worded warning!
Anyone attempting to use a vapor service fuel injector, or a gasoline/petrol injector for liquid propane applications is in serious jeopardy of inviting an engine fire, a hydrostatically locked engine with uncontrolled fuel expansion into the crankcase, exhaust, or upper valve train areas, a blown apart fuel rail with disastrous consequences, injury, or worse. Since the liquid is 270 times more dense than vapor phase, and is very thermally reactive, anyone thinking of pressures should probably double their best guess to start. I know personally of several systems that have had over 450 psig in the fuel rail and tank, just from heat absorption from the engine.
Liquid propane injectors are hand matched, precisely machined components with precision orifices. The control strategy is VERY, VERY hard to implement. The one system used here in the US is purpose built and only suitable for very few applications, none aftermarket for the user-built. The ones used in Europe and down under are uniquely designed and also precision components.
Lastly, please be very careful when working with modified gasoline or other components in liquid phase propane/LPG, interesting things can happen very quickly, and traditional methods of mitigation may not work.
Just ask how I know, been there, done that.
Franz

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[surfdancer]

I was involved in some basic R&D work for LPG fuel systems. One issue that constantly hounded us is the heavy hydrocarbons (propylene, etc) in LPG polymerizing and clogging fuel injectors and other components exposed to heat soaks. As Franzh stated, most OEM systems are careful balances of component interaction and have limited application outside their initial design.