Current State of Liquid LPG Injection

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Noccer
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Current State of Liquid LPG Injection

Post by Noccer »

Hi Guys,

Getting time to build the next V8 for the Landy, and I always said that if I could go for liquid LPG injection I would build an engine made for it (like 11:1 CR). A few years ago I heard there was a system but the pumps tended to fail and they were very expensive (presumably they fail because LPG has no lubricity additives - and they would be tricky to add to the tank).

To save a lot of searching - can anyone here give me an update on the current state of play ?



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Re: Current State of Liquid LPG Injection

Post by stevieturbo »

Noccer wrote:Hi Guys,

Getting time to build the next V8 for the Landy, and I always said that if I could go for liquid LPG injection I would build an engine made for it (like 11:1 CR). A few years ago I heard there was a system but the pumps tended to fail and they were very expensive (presumably they fail because LPG has no lubricity additives - and they would be tricky to add to the tank).

To save a lot of searching - can anyone here give me an update on the current state of play ?
What pumps ?

There are no commercially available liquid injection systems

They are all gas injection, and I dont recall any using a pump. I thought they all relied on gas pressure alone in the tank to supply it to the front.

There are various lube systems available, but they are to prevent valve seat recession.
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Post by ChrisJC »

I have been keeping an eye on this one on & off.
These people have been promoting it for years:
http://www.lpgli.com/
I also found a reference about it here:
http://www.arunautogas.co.uk/autogas_lpg_conversion.htm
which suggests that it isn't quite ready for the prime-time yet!

What I don't understand is how they stop the injectors from freezing up.

Chris.
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Post by stevieturbo »

Details on the liquid setup seem to be sparse.

It would be fantastic when it does become available though !! That higher octane and cooling effect could be very useful.

I think I would have a go at switching my own car !


I guess there are 2 options. Use engine heat to do it, or electrical heat. There could be heating windings around the injector to electrically heat it to prevent freezing. Or maybe until such time as there is heat in the cooling system to use.
or maybe the injectors are simply designed to operate in "cold" conditions
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Post by davehoos »

these where going to be common and advertised in the 90's.the early demostration engine was early 80's holden 6 and the gas flowed in though the side of bosch injectors.and the fuel rail was heavy modified.

didnt know these are still around as vapour injection is common-factory ford run viallie fixed venturi.electric controled injection systems are due this year for ford-gm.

when i did my installers lience the hassel was that no pump was allowed inside the fuel tank and the cost of the seporate engine management.these are now cheep or piggback ecu that convert the original pulses.

the internal pump i dont think has been allowed by australian standards-but an external pressure pump is easy.im assuming that pump life questions had more to do with being hard to replace.

no heating on the duel fuel injectors.might have been the circulating petrol.
throttle body units would have to be heated--or just the throttle plate or
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Post by stevieturbo »

davehoos wrote:these where going to be common and advertised in the 90's.didnt know these are still around as vapour injection and electronic thottle body injection.

when i did my installers lience the hassel was that no pump was allowed inside the fuel tank and the cost of the seporate engine management.these are now cheep or piggback ecu that convert the original pulses.

the internal pump i dont think has been allowed by australian standards-but an external pressure pump is easy.im assuming that pump life questions had more to do with being hard to replace.
What's the score with the vapour injectors ?

I know a single regulator is limited to roughly 350-400bhp.

But what sort of power can a single injector flow gas for ? And are they all fairly normal 12v operation ?
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Post by Noccer »

ChrisJC wrote:I have been keeping an eye on this one on & off.
These people have been promoting it for years:
http://www.lpgli.com/
I also found a reference about it here:
http://www.arunautogas.co.uk/autogas_lpg_conversion.htm
which suggests that it isn't quite ready for the prime-time yet!

What I don't understand is how they stop the injectors from freezing up.

Chris.
Thanks for the post with links
(see also http://www.vialle.nl/home.html?L=1).

Maybe some clarification - two big benefits as far as I see it.

First you can do away with the petrol tank, and everything petrol related. Even in my Land Rover I don't want a tank inside blocking up the load bay.

Second is the LPG is a liquid right up to the point of injection, and it is at normal engine bay temperatures. It needs to be at reasonable pressure to make sure it doesn't boil in the injector rail - but nothing like the super high pressures in common rail diesels (but obviously at a higher pressure than the LPG tank, as it is going to get hotter than the tank). The injector will sit at a temperature somewhere between the incoming LPG and the inlet manifold temperature - but when the LPG comes out of the injector it flashes to vapour getting really cold, which cools the air mixing with it, and cold air is more dense, so you get quite a lot more air in the cylinder. It makes for better power and better fuel efficiency.

And LPG is high octane - a bespoke engine will run high compression without pinking. Now not many LPG customers would actually build an engine just for LPG - but I have a spare V8 sitting on my bench waiting for the rebuild. I also have a fully programmable fuel and ignition system.

But sounds like they still have problems - though not in Australia if you belive the blurb ! Some sort of problem seems to be holding this development back, or I think we would see more of it.

Steve

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Post by ChrisJC »

Noccer wrote: but when the LPG comes out of the injector it flashes to vapour getting really cold, which cools the air mixing with it, and cold air is more dense, so you get quite a lot more air in the cylinder. It makes for better power and better fuel efficiency.

Steve
You have to be very careful that it doesn't liquefy, otherwise it'll be all droplets rather than a nice gas.


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Post by stevieturbo »

Just like nitrous, as soon as the LPG enters air....it boils into a gas.

Which is exactly what you want as it will offer great cooling benefits.

Thats where current LPG vapour injection systems lose out. ( well, from a performance point of view anyway, especially with boost :P )
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http://www.youtube.com/watch?v=XgWRCDtiTQ0

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Post by bobtail84 »

A mate of mine was at Brands Hatch late last year where a pair of Fords had LPG liquid injection fitted and ran very well. I will find out more info but he was very impressed. He runs a business in the LPG game and we have MegaSquirted a V8 with LPG vapour injectors with some success and are in the process of fitting LPG injectors to my MS'ed V8 so we can run it on the road then datalog and tune like petrol.

Jeff
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www.essex-ms.co.uk

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Post by stevieturbo »

bobtail84 wrote:A mate of mine was at Brands Hatch late last year where a pair of Fords had LPG liquid injection fitted and ran very well. I will find out more info but he was very impressed. He runs a business in the LPG game and we have MegaSquirted a V8 with LPG vapour injectors with some success and are in the process of fitting LPG injectors to my MS'ed V8 so we can run it on the road then datalog and tune like petrol.

Jeff
Bedford Autodrome, Palmersport. All their cars run on LPG.

makes perfect sense. Why the hell should a car that never sees the road, pay extortionate amounts of fuel duty when using petrol ?
At least on LPG they save some.
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202mph standing mile
http://www.youtube.com/watch?v=XgWRCDtiTQ0

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Post by Noccer »

stevieturbo wrote:Just like nitrous, as soon as the LPG enters air....it boils into a gas.

Which is exactly what you want as it will offer great cooling benefits.

Thats where current LPG vapour injection systems lose out. ( well, from a performance point of view anyway, especially with boost :P )
Thanks, you and I are on the same page.

For those not so familair with LPG, it is mainly propane. Propane really does want to be a gas when you let the pressure off - the process of 'flashing' to a gas takes a lot of heat. If the tiniest fraction of super cold liquid is left as droplets then the mixing with air will evaporate that too. So no worries about liquid with liquid injection - however. this is not the case for gasifiers/evaporators, they need heat otherwise the same effect will make them so cold (they are normally an aluminium chunk separate from the engine) that the liquid will not want to flash. You have made your own super cold fridge ! Which is why you start on petrol and get some warmth first.

Steve

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Post by stevieturbo »

So what pressure is normally in the LPG tank ?

What type of hose is used from tank to regulator ?

What sort of gas flow will a single injector support ( ie power ) ?

What sort of power requirements do the injectors have ( ie current ) ?


Maybe a nice option for boost.....normal LPG system. With an additional injector or two linked to the main LPG tank, which will inject liquid propane on request to back up the normal LPG usage, but cool the intake charge too.
or just use a Nitrous style solenoid to do it.
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Post by davehoos »

the problem with injected LPG is that the gas is not of consistent quality.]
liquid injection requires precise amounts to avoid leanouts.I was at a cummings diesel workshop and they were trying to tune via phone data a large computor controled GAS generator running on coal gas.

most countries no longer have 80-95% propane.
most countries are 50-50% with other wax type products added to give 90.5 octane.its the crap in the mix that can stay liquid.

the pressure ive seen was 60PSI the same as most petrol injection.the idea is that is returns to the tank--circulates.
dont quote mwe on that.

vapour injection is supplied from the tank at 700 KPA.

liquid ingectors run into problems if before the trottle plates.a local company does liqid injected assist fuel on diesels.
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Post by Noccer »

Your post seems to have different bit of different things. Certainly we are not talking about LPG addition to diesel injection here (either as gas or liquid). So forget that part. Presumably Cummins Diesels are interested in diesel engines.

If LPG contains waxy susbstances then that will mess up a vaporiser on a conventional system, but should be less of an issue with liquid injection of LPG. However I suspect that there are standards for AutoGas that mean it has a tightly controlled composition. If you are using heating gas from a chicken shed it might be made to a different standard. Changes of butane/propane ratio could be accomodated by normal lambda sensior control on a conventional IC engine system.

All petrol injection systems I am familiar with work on a pump to raise to injection pressure, then a pressure regulator controlling flow back to the tank. That would be the same with LPG. I assume you have read the Vialle web pages.

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