LPG - Liquid Injection 3

[jbond]

Are there any kits out there that inject LPG in liquid form so that when it changes state to the gas, it removes the latent heat from the charge air (turbo application) and has the effect of cooling the intake and with high octane rating as a bonus? The injectors in such a system would be similar to typical petrol injectors (ie not a venturi carby system)

Also, do any of these kits allow you to remove the petrol fuel tank and petrol injectors?

 

[patprimmer]

yes and yes

Regards

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[jbond]

Excellent, thanks for your feedback. It's quite hard to find such a kit where the manufacturer actually says you can remove your petrol tank.

Are you able to name some of these kits or manufacturers so that I can do some more research? I think I've exhausted google without having some new search terms.

 

[IceStationZebra]

Why would you ever use your petrol tank with an LPG system, unless you are running a dual fuel system? A petrol tank is not even close to being a suitable LPG tank.

ISZ

 

[patprimmer]

Before installing LPG system. Remove petrol tank and if convenient remove all associated fittings to increase room and reduce weight.

Print this and add to instruction book. Problem solved.

I don't know specific kits.

I don't google for others.

Try to google component manufactures, like LPG injectors.

LPG fuel pumps.

LPG engine managment systems etc.

Regards

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[jbond]

Some installers say that you need to keep your petrol system for engine startup and engine shutdown, in order to lubricate this or that

If I installed LPG, I would want to remove the petrol system entirely - I don't like extra redundant weight

 

[patprimmer]

How does the petrol system lubricate anything. Unleaded petrol is a very poor lubricant.

Regards

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[IceStationZebra]

I worked for a forklift OEM for 4+ yrs. They used GM and Mazda engines converted to LPG in 90% of the trucks sold in the USA. The only changes they made to the engines for LPG was installing valves made from better material (especially exhaust) and fit valve rotators to get acceptable life. Be aware that there is a small amount of tar in LPG and it can leave nasty deposits on the valve stems.

They did not use petrol to start/stop the engines nor have I ever heard of this practice. The idea behind dual fuel systems is you use the fuel that is most economical or available.

ISZ

 

[franzh]

Using gasoline/petrol to start an engine brings several benefits. First, it keeps the injectors and pump operating for a few seconds, flushing any debris and keeping the fuel fresh.

Second, it helps with cold starting. Older mixer style systems may not start easily on cold mornings and using petrol to start made it easier.

With vapor injection, there has been a concern about getting a slug of liquid past the vaporizer on cold start and freezing the system. Some use petrol start while others do not.

With liquid injection, these injectors take the place of the petrol injectors, thus, using petrol to start is difficult, since the petrol system is removed from the vehicle. There are a few bi-fuel/liquid propane injection systems around, but not many, not that its impossible though.

Franz

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[TDIMeister]

http://www.gaskit.de

 

[j79guy]

jbond:

A search of this site is in order, this topic has been discussed at length before, and you may garner some good information from those threads.
I believe Bi-Phase has a liquid kit currently available for the GM Vortec 8100 engine.
Franzh has forgotton more than most of us will ever know on the subject, he is "the man".

j79guy

 

[franzh]

Gosh, 79, I am turning multiple shades of red! I appreciate the kudo's.

Bi-Phase is a captive product of Schwans for their internal fleet. I am not aware of any outside installations and sales.

The GM Vortec 8100 is being installed with CleanFuelUSA systems on select cab and chassis applications, plus it has EPA certification. It is the host design for the Roush LP Truck and is being upfitted to Bluebird School Buses. I've driven a few of the converted vehicles and the performance is impressive.

Franz

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[englishrancher]

About liquid propane injectors...how is the injector able to survive the extreme range in temperatures from the -43 degrees of cryogenic liquid to the instant combustion temperatures of 500 degrees+ ? I would think the sudden and extreme difference in temperature would crack the metal of both injector, piston and combustion chamber wall.

Englishrancher

 

[drwebb]

PV = nRT

Prolly the same way a barbecue burner does.

 

[franzh]

Propane is not stored in cryo form. It refrigerates only when the vapor phase is reached. The injectors control propane at ambient temperature (ambient underhood temperature, that is). The injectors are NOT direct cylinder injectors, they mount where the original gasoline injectors are, upstream of the intake valve.

The biggest issue with LPI injection systems is sourcing injectors that will handle the pressures, and they are NOT standard gasoline injectors.

Franz

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[marcusaurailius]

Have you thought about standing the ..bottle.. upside down ??

a lot of the trials cars use gas, and the bottle is upside down, so that the gas stops liquid till it gets to the carb.

they say it gives better response

Marcus

 

[patprimmer]

A correctly installed automotive LPG tank does have the fuel pick up in the bottom of the tank for the reasons you just stated. They do it by having a tube inside just like a petrol tank.

Regards
Pat
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[Bribyk]

Yes, don't try to hook an automotive tank to your barbecue to use up the rest. Unless you don't like your barbecue...

 

[turbocohen]

About liquid propane injectors...how is the injector able to survive the extreme range in temperatures from the -43 degrees of cryogenic liquid to the instant combustion temperatures of 500 degrees+ ? I would think the sudden and extreme difference in temperature would crack the metal of both injector, piston and combustion chamber wall.

Englishrancher

Port injectors designed to meet the requirements of handling the full range of liquid phase propane temperatures and pressures have been in use since the 80's. The one I am most familiar was derived from a very high vapor pressure gasoline injector that was designed to overcome hot gasoline handling difficulties. Yes, dealing with higher pressures and lower temperatures was an issue but basic design mods took that into account long ago. Also thermal shock and metal fatigue used to fracture metering orifice plates on earlier designs.

Newer DI designs in the works seem promising but all have one common pitfall.. deposits. Tip coking and overall clogging are much more difficult to deal with due to higher polymerization temps, especially after hot shut down causes fuel boil out of the injector leaving trace heavy residues behind. Sulphur is as bad today as it was 20 years ago.

Motor Grade LPG is still not widely available and deposit control additives with proven clean-up and keep clean properties are not widely available yet.

Cheers, TurboCohen

 

[patprimmer]

I think the grade of gas for auto fuel varies considerably from country to country.

Regards
Pat
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