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

 

[patprimmer]

I believe liquid propane injectors are commercially available. Try a google search.

Also gas phase injectors are available

Regards
pat

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[obanion]

Believe me, I have google searched for hours. Can't find anyone selling liquid propane injectors, can't even find a reference or tech sheet to such a thing existing.

If I did, I'd bet the flow rate would be insufficient.

Found vapor injectors, they can only do like 40HP/injector, no go there.

 

[patprimmer]

I have anecdotal evidence that there is a sysyem being made in Holland for liquid phase injection of propane, but I have no recorded details

Regards
pat

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[obanion]

Any theory as to if side-feed injectors may tolerate the pressures better than top-feed? The potential for the injector to blow open is far less, as the fuel rail actually surrounds most of the injector.

 

[pulsewidth]

Clean air Partners in San Diego makes a variety of large flow CNG injectors.
Quantum in Irvine, Ca. makes very large flow injectors for hydrogen.
Bosch makes CNG injectors for lots of OEMs.

Regular pintle injectors such as Bosch 403 have been used in the past with methanol in Indy Car engines at pressures up to 10 bar without
damage or leakage.

 

[franzh]

First a clarification: for liquid LP injection, you will need injectors with the capability of at least 50 psig above vapor saturation, or around 350 to 450 psig. As you already noticed, this is no small feat. There are some companies making systems which includes a custom tank, electronic interfacing, injectors, injector lines, etc, but they are vehicle specific. I believe Prinz of the Netherlands, several Italian, Australian, New Zealand and Canadian companies are also playing around with LPPFI.

This is not to be taken lightly, as contemporary injectors will pop apart around 120 psig. The one American company, formerly known as Bi-Phase, custom made their injectors and had great difficulty here also. I dont know of their source of cores and most of my contacts there have left. (Bi-Phase has been acquired by Schwans, the food prople.)

The BKM, Clean Air Partners, and Bosch do indeed make CNG injectors, but they are typically low pressure, seldom above 2 bar, and are designed for vapor only. I have no experience with the Indy type 10 bar methanol injectors, but I suspect they are hand built to exacting tolerances, certainly not off the shelf. I have seen the side and bottom feed injectors, but all of the LPPFI injectors I have seen in the field are contemporary appearing.
Franz

 

[obanion]

Why would I need 350-450psi? I was planning on using tank pressure and cooling the liquid propane on it's way to the engine. I'd also have some sort of vapor purge for hot starting. Because I'll also have a well ventilated engine bay, it's a inline with one side being cold, one being hot, and the intake manifold itself will be kept pretty cold (built in liquid/air intercooler and phenolic spacer to head), I'd think it would stay liquid.

This also isn't a daily car. It doesn't need to handle 100F days, as I'd never drive it on days like that, and we have so few of those anyway in Oregon.

I'm still thinking side-feed injectors may be able to live at these pressures as they won't be able to bust open at the center. At least they would have a better time than top-feeds.

I'd love it if a injector existed that could flow 76lb/hr of liquid propane at 120psi, but so far, none are for sale.

I'm gonna call Bi-Phase, but I'm betting I get the same response I usually get "not for sale to the public."

 

[franzh]

Keeping the LP cool would certainly help. Saturation pressure at 70°F is about 120 psig, so you will need to keep it at least 50°F. The reason you need it boosted is to keep it in liquid phase to avoid heat saturation at the engine. Your idea to vent the vapor into the bay is a little risky though. Have you thought to purge the vapor into the intake during start up to assist there? You could use a single point PWM injector.

Bi-Phase will not sell to the public, I've tried, and I know (knew) the principals, designers, and tech staff well. 76 lb per hour is a lot, you may need to pair injectors for that flow rate. Its been done before.

You will also need to create your fuel flow tables with pressure and temp as inputs.

This could be interesting project, how large is the engine?

Franz

 

[patprimmer]

Onya Franz

I knew you would be the one to come through with the details.

I sometimes wonder , if in order to maintain constant fuel pressure, the propane tank could be heated with a thermostatically controlled electric blanket, with the thermostat set high enough to give enough pressure to avoid vapourisation of the propane in the lines.

This would restrict the need for purging after hot soak to the injectors only, and would remove one variable for calculating fuel metering.

Regards
pat

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[obanion]

Heating the tank (increasing system pressure), then cooling the fluid as it goes to the engine bay is one idea. I'd rather increase the distance between target LP temp and vaporizatio LP temp (at whatever pressure I'm at), by using some type of pressure boost, with very cold LP temps.

I pondered perhaps just cooling the whole container of propane, then using a inline pump to get pressure up. If I could cool the propane down to say 40F, the tank pressure would only be 65psi. Then I could use a inline pump to get pressure up to about 100psi at the injectors. The LP would stay liquid so long as it didn't get above 65F at that pressure.

One of the plans for the engine was to put the AC evaporator inside my antifreeze reservior for the liquid/air IC. I could also use this fluid to cool the propane in any number of ways, be it the tank, or just the fluid on the way to the motor.

I could start and idle the motor on a fixed vapor amount through a orifice, then run the AC to cool down my reservoir, then switch to LP once the coolant is cold enough.

I was NEVER going to purge vapor under the hood. I was planning to purge vapor into the engine.

 

[franzh]

One method I experimented with was self refrigeration. Take enough vapor from the LP tank during starting and low speed running and the tank temperature and pressure will drop low enough. Note that this is highly variable due to ambient weather conditions, tank size, tank fuel level, etc. Toss in about 8 more input parameters into the fuel injection logic.
If a pressure sensor detected increasing tank pressures, the LPPFI system would decrease while increasing the vapor system.

Using a pump to boost pressure is fine, but remember that if the engine is ever shut off, the rail pressure and temp may hit 350°F during soak and ruin everything! Thats why the tank pressures are so high, plus the need for a purge return line.
Franz

 

[Dynocat]

Mitsubishi GDI injectors run at pressures over 250 psi in order to inject Gasoline directly into the combustion chamber. They are slightly larger than standard fuel injectors. One part number I have is DMX078132C. How well/long they will work on liquid propane...Anyway you may need to order them from a UK supplier, as GDI vehicles are not big in the USA. They also are not cheap.

 

[magnograil]

The mechanical injection 911 engines (early '70s) used high pressure injectors (I believe around 240 PSI) but they are essentially diesel type, spring loaded valves with a high pressure supply pump. I take it you are looking for electromechanical types?

 

[NeilDS]

When I worked at Siemens, I work on an LPG program for the Chrysler 5.2L V8 engine. This was a multi-point system utilizing the Siemens Deka II bottom feed injector. There is an example in this Orbital literature.

http://www.orbeng.com.au/orbital/aboutOrbital/pdf/OEC_SYN.PDF

They were able to take the required 400psi. I don't have a part number for you and doubt they were ever sold direct to the public. They did produce some LPG vans in Canada with these injectors.

 

[turkeyokato]

Hi Obanion,
How did you go in your search for an injection system for LPG? I have come across half a dozen companies around the world that have told me they can sell me the gear to sequentially inject LPG into my turbocharged engine up to 500HP.
When I get time to digest it all I will.
If you want me to email all the replies (3 pages worth) let me know your email and I will send them through.
I just found this forum and have written to franzh about what the best timing curve would be for my 265CI Valaint Ute. Did you get the 360 running (RE: LPG for performance)?
Cheers.

 

[Aero55]

Turkeyokato-
I am working on a similar project, of LPLI system. It is a lower power generator application, but I would be interested in seeing the replies of the injector companies that you do have. I have looked at many injectors but only able to come up with one or two that might be feasible for me, and I'd like to cross reference against your list.

ETeene@Dal.Ca
Thanks,

 

[willeng]

obanion

This may help

http://www.cleanairpower.com/components/products.html

 

[franzh]

Willeng:
These injectors are designed for gasesous natural gas or propane and are not suitable for liquid propane. The last time we investigated them (they are excellent vapor phase injectors) the orifices are too large and the moving compenents are too heavy to work against the liquid propane, and at the action cycle time needed. With large orifices these CNG injectors have, the open duration is measured in well under .01ms.
Franz

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[willeng]

franzh

No worries, i was unsure not being into this side of things, i just stumbled onto them when looking for something else. The info you supplied on them is interesting though!