LPG injection

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MAGP
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LPG injection

Post by MAGP »

Anyone ever considered LPG injection with an older delco?
There is an interesting thread on the alternative fuels forum that deals with Megasquirt having been modified for this capability. I'm no coder but I can certainly be a tester if anyone has the opportunity to sit down and work through the theory and coding.
Charlescrown
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Re: LPG injection

Post by Charlescrown »

Having had quiet a bit of experience with the older LPG systems I see big benefits of liquid injection particularly with the cooling effect during vaporization. That has been the downfall of gas systems because of the dry gas entering the engine and the change occurring in the convertor. I have no knowledge of current liquid injection systems but have a vague idea. You would need special injectors due to the high pressure of the fuel but can see the benefits. I'll be interested to see if anyone takes this project on.
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vlad01
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Re: LPG injection

Post by vlad01 »

there is 2 different types of lpg injection, liquid and gas injection.

liquid is the raw liquid pressurized lpg very much the same as efi.

Gas injection uses a special vaporizer much like the standard systems and that is fed to a low pressure rubber hose where big bulky special injectors fire gas into the runner or ports.

The 1st system is a lot better, the later is a heaps of shit just like traditional systems but more complex and prone to failures.
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.
MAGP
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Re: LPG injection

Post by MAGP »

Charlescrown wrote:Having had quiet a bit of experience with the older LPG systems I see big benefits of liquid injection particularly with the cooling effect during vaporization. That has been the downfall of gas systems because of the dry gas entering the engine and the change occurring in the convertor. I have no knowledge of current liquid injection systems but have a vague idea. You would need special injectors due to the high pressure of the fuel but can see the benefits. I'll be interested to see if anyone takes this project on.
I gather you didn't look at the link. It is about gas injection not liquid injection. As far as I am aware you can't retrofit liquid injection in Australia because it is heavily regulated and each kit is made for particular vehicles and manufacturers are required to comply with safety and ADR regulations.
vlad01 wrote:there is 2 different types of lpg injection, liquid and gas injection.

liquid is the raw liquid pressurized lpg very much the same as efi.

Gas injection uses a special vaporizer much like the standard systems and that is fed to a low pressure rubber hose where big bulky special injectors fire gas into the runner or ports.

The 1st system is a lot better, the later is a heaps of shit just like traditional systems but more complex and prone to failures.
Gas injection is nothing like traditional systems. I'm an authorised LPG mechanic, and rego inspector, and I know the difference between all the systems The crappy systems are the ECU controlled vapour systems that are fed into the airstream via a "spud". The systems that use injectors from Prins etc are actually quite good and reasonably priced.

Just to be clear, and I should have put in in the OP instead of relying on people reading the link, I am referring to gas injection not liquid.
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vlad01
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Re: LPG injection

Post by vlad01 »

I've had my dealing with those gas injection system and there was all sorts of issues with injectors failing and the vaporizer needing rebuilding more often that you'd want.

I mean traditional as in they still use a vaporizer plumbed to the heater circuit.
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Jayme
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Re: LPG injection

Post by Jayme »

there be some interesting reading there.

from that link wrote:in the MS2extra code, there is a function called flex-fuel that is intended to read out a alcohol-content sensor and correct the fuel injection times accordingly.
I rewrote this function completely to read the fuel temperature and pressure using a combined MAP & LPG/CNG pressure and temperature sensor supplied with the AC Stag 300 sequential LPG injection kits.
The fluid dynamics behind all this is called "choked flow of a compressible fluid through an orifice"

so all you would need is to have 2 inputs to the delco to read the gas temp/pressure and then beg VL400 to rewrite the 12P code to use that data correctly. perhaps this can be tackled inline with the flex fuel project spoken about in the other thread?
MAGP
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Re: LPG injection

Post by MAGP »

I agree. I'm willing to test if VL400 is willing to write the code and the inputs (a daughter board maybe?) can be made.
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Re: LPG injection

Post by Charlescrown »

There are quiet a few aftermarket liquid LPG kits on the market that I am aware of. As I said I do see a big advantage over the old gas systems (the term vapor is a bit misleading it's gas or liquid in my books) and yes I stopped reading the blog as it started to get boring when I could see it was nothing exciting. I am amazed anyone is still using the spud system. It's gotta be the most primitive system you can get. I see no legal reason why the addition of a Delco ECU to control the injectors and ignition could not be used which compared to the basic ECU's for gas could not be used as long as it complies with the relevant emission ADR for that car.
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Re: LPG injection

Post by bldnut »

I have done this 9 years ago on the misses EK holden running a 202 and straight vapour injection, back then I used an 808 and 5d to tune it I didn't bother about gas pressure as the convertor is basically a fuel pressure reg, the biggest problem I had was living in central vic and when the temp got below 4c the car was a pig to start (gas has a turning point at 4c and 1L of liquid makes 270L of vapour) cold start enrichment was a prick to tune, I also had to fit an electric water booster pump to stop the convertor freezing if the car didn't start first go. apart from that the car worked perfectly and was her daily for almost 2 years.
MAGP
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Re: LPG injection

Post by MAGP »

@bldnut what injectors did you use and how did you setup your 808s injector settings to use them?
I had considered doing a similar thing a while back but the injector settings are the only hurdle left.
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