dedicated propane injection systems

Propane, Butane, LPG, GPL, C3H8, C4H10
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kikkegek
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dedicated propane injection systems

Post by kikkegek » Tue Nov 13, 2018 8:16 am

hi guys,

I havent gotten to retrofit my propane vapour injection system to my V8 big block yet.

And I am always looking for new info. Especially if there are dedicated propane injection systems. All so far require a gasoline system to preheat the engine coolant to 40C and then switch to propane vapour or liquid injection injection.

But I found two company selling dedicated liquid injection systems, that supposedly even use the original ECU and just reprogram it.

http://www.bi-phase.com/systems.htm

and https://www.roushcleantech.com/fuel-system-overview/

I have emailed Roush twice but have not gotten any response.

What wonder and am curious about is two things:

1. how can they cold start and not freeze the system? injectors?

2. are they really using high impedance propane injectors?

are you guys familiar with any of these two?
daily: 1974 GMC 25HUNDRED Suburban - fresh rebuild 350 small block - TH350-NP203 - 4.1 end gears - IMPCO425 mixer - IMPCO model E vaporizer
project: 1977 GMC C15 Suburban - 454 big block - TH400 - gasoline
sold: 1986 Chevrolet Suburban K20 Silverado

C3H8
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Re: dedicated propane injection systems

Post by C3H8 » Tue Nov 20, 2018 1:43 pm

The difference between Rousch and BiPhase systems from others are that they are liquid injection, not vapour. There may be others but three NA systems use LPI not VI.
There is Clean Fuel Systems (Somewhere on the east coat). Their system is used on BlueBird school buses and possibly some others. They are also used in newly manufactured Propane delivery trucks, mostly single axle, and other single axle commercial vehicles. Those using it currently tell me they are quite happy with it. The only issue is finding a dealer that is convenient if they need servicing.

BiPhase (LPEFI) was originally designed by a guy named Dave Bennet outside Minneapolis, MN. if memory serves me correctly. It was 20 years ago when I met him and he was first developing the system for Ford CV and Ford E250 and E350 vehicles. Bennet sold the rights to the system to Schwans Food and Ice Cream delivery services in early 2000's I believe. You need 12 to 15K to buy a BiPhase system. At least that is what they wanted in Canadian dollars just for the kit a few years ago. They also focused their attention on GM trucks such as the TopKick or Ford School buses and F600 or 700 single axle size.

Rousch designed their system for Ford vehicles including the F and E series. He even made a 1/4 mile specialty vehicle his daughter raced. I never did see it in action or how well it did or if it even made it to the track.

All the systems operate in a similar manner. They require a tank manufactured by Sleegers (NA, could be others though) with an electric fuel pump in the tank. Liquid injection requires a consistent minimum pressure (usually 35 to 75 PSI over tank pressure). Although some may change the programming in the ECU, BiPhase originally did not do that. They kept the Ford programming and installed modified injectors in the vehicle that suited the existing ECU programming. This meant specific injectors for each model of vehicle. All the systems work on propane supplied by the tank pump and returning fuel to the tank through a regulator post injector rail. It's identical to the existing gasoline systems back in the day before direct injection and returnless pumps entered the market.

My only opportunity to drive a vehicle was an E350 with the BiPhase system. It worked flawlessly and had some neat features added. All BiPhase conversions included a key fob to unlock the doors. Liquid injection systems tend to have the fuel in the rail vapourize when they are shut off with a hot engine. This made for poor starting hot as the ECU expects liquid to pass through the injectors. Providing the key fob triggered the doors and started the electric pump to get liquid through the lines before the driver reached the vehicle to get in, enabling better fuel control by the ECU and therefor normal starting like gasoline and no waiting like the Dodge system described below..

The only other injection systems worldwide I am aware of at present are Vialle. They have been making and selling LPI since the mid 90's. They also incorporate a tank of their own design in the tank. They prefer dual fuel with gasoline start but it could handle straight fuel also

Lastly Chrysler/Dodge made a liquid injection system for there dodge B150/250 series vans. It had mild success other than starting issues from time to time. They incorporated 2 pumps in the tank. When starting the engine a light would come on saying to wait when the key was turned on. When the light went out it meant the lines had been evacuated of vapour. To do this quickly the ECU ran both pumps during the wait period and the cranking cycle. After the engine started one pump shut down. The pumps were shut down alternately each start cycle to maximize pump life. Unfortunately they had quite a bit of trouble with the iron sulphide powder you see from time to time destroying the pumps. Warranty costs were so high they stopped producing the system.

There is lots more detail but I think this covers the systems I am aware of. I'm sure there are others either offered for sale or being developed in other countries. The main stumbling block in Canada and the USA is the price of propane compared to gas. With Labour and parts ranging from $5000 to as much as $15,000 the emission advantage may be there over gasoline but like electric vehicles the payback period is just too long with out some form of subsidy.

C3H8
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Re: dedicated propane injection systems

Post by C3H8 » Tue Nov 20, 2018 1:47 pm

To answer your two specific questions. They use the same impedance as the gasoline injectors.
The propane doesn't freeze because it is a liquid right until it leaves the injector tip. The volume is so small (270 times expansion) the heat of the engine keeps any from staying frozen to the injector tip. The constant pressure from the fuel pump keeps the propane liquefied until it is released by the injector.

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kikkegek
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Re: dedicated propane injection systems

Post by kikkegek » Tue Nov 20, 2018 2:37 pm

thanks for the extensive eanswer C8H3. I guess it's not an option to retrofit a system like that on an old engine?

only thing holding me back from installing a vapour injection system is that it will not start at low temperatures. From what I can find you always need a way to preheat the coolant. I have been looking at the 12V coolant heater from diesel engines, but that would also then require an electrical waterpump, because you need to start circulation before the engine starts (I think).

I should probable just try such a coolant heater in my current setup and monitor how it heats the coolant.

I guess there is no such thing as a dedicated vapour injection system
daily: 1974 GMC 25HUNDRED Suburban - fresh rebuild 350 small block - TH350-NP203 - 4.1 end gears - IMPCO425 mixer - IMPCO model E vaporizer
project: 1977 GMC C15 Suburban - 454 big block - TH400 - gasoline
sold: 1986 Chevrolet Suburban K20 Silverado

storm
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Re: dedicated propane injection systems

Post by storm » Wed Nov 21, 2018 3:54 am

kikkegek wrote:
Tue Nov 20, 2018 2:37 pm
I guess there is no such thing as a dedicated vapour injection system
There is in Australia, a system called ProFire is available but I'm not sure if they will deal with people outside Australia.

A guy I work with fitted a system, not ProFire, to a 3.9 litre Range Rover and he uses a Megasquirt 3 ECU with injectors and regulator from Poland (can't remember the name sorry). The regulator is tiny but is appears to have plenty of capacity for what he uses it for.
Every job is a self-portrait of the person who did it. Autograph your work with excellence.

Fuel flow requirements calculations viewtopic.php?f=5&t=1638

C3H8
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Re: dedicated propane injection systems

Post by C3H8 » Wed Nov 21, 2018 3:34 pm

Nothing is ever impossible in this industry. As storm mentioned there are some aftermarket ECU's that could make it possible. Just the same a petrol injection can be retro fitted to an old engine propane injection could also be possible. I don't have the knowledge to do that but there are some really bright guys on here, or there were.

With the existing popular brands there are three road blocks.
1. Fuel pressure. If you live in a colder climate the tank fuel pressure drops below the outlet pressure of the regulator. Most injection systems require approximately 2 bar or 28 psi of pressure for perfect operation. They can continue to function down to 1 bar or a little less but any sudden demand will trigger a return to gasoline. The solution is two fold. You could use a tank warmer to maintain adequate pressure in the tank. Calculations would be required to figure out the best warmer, and controls would be required to turn a warmer off so pressure in the tank does not get too high.
2. Cold starts. The current ECU's used by Prins and BRC and others that are similar use an algorithm to calculate the correct flow through the propane injector. Unfortunately due to the 2 bar regulator this means some liquid can enter the fuel rail on start up if the lockoff is turned on too soon. The amount of propane would be too rich even if the algorithm was perfect because of liquid sneaking through before the regulator gets warm enough to vaporize it all.
3. A cold engine ECU is set richer for the first few minutes and again the tendency of liquid to get past the regulator continues to present issues.

The liquid issues are not insurmountable but most of the suppliers are happy with the gasoline start cycle until the engine warms up and many of the customers don't live in colder climates resulting in unwanted changeovers. Tanks with pumps are expensive and proper warmers would require research to establish a reliable system. Years ago tanks were made with both vapour and liquid valves. Regulators for some companies were too small to provide proper vaporization in cold weather until the engine reached sufficient temperatures. The solution was to run both a vapor line and liquid to the regulator. At night the driver would shut off the liquid valve and allow the engine to run the line out of fuel. In the morning they would turn the vapor valve on and warm up the engine. once warm they would turn the liquid valve on and the vapour valve off. Pain in the butt but that way they didn't need petrol to warm the engine up. Companies that used the products with larger regualtors didn't have to do this, however some still did as they found it more reliable, especially if they didn't have the capability to plug in an engine warmer overnight.

Most LPI systems don't have to deal with algorithm issues because they remove the gasoline injector and install a resized injector for propane and as previously mentioned they use a pump in the tank to maintain adequate rail pressures.

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kikkegek
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Re: dedicated propane injection systems

Post by kikkegek » Wed Nov 21, 2018 4:28 pm

thanks man.

yes thats what I have found out so far. and I head that the liquid LPG can damage the injectors of a vapour system.
daily: 1974 GMC 25HUNDRED Suburban - fresh rebuild 350 small block - TH350-NP203 - 4.1 end gears - IMPCO425 mixer - IMPCO model E vaporizer
project: 1977 GMC C15 Suburban - 454 big block - TH400 - gasoline
sold: 1986 Chevrolet Suburban K20 Silverado

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