I have been asked on a couple of occasions for info on converting customers' cars to LPG. Also whether Diesel engines can e converted. I recently saw an advert in Car Mechanics magazine for such kits to convert Diesel engines. Considering offering it as a service. Any opinions/ horror stories???
Thanks
Andrew
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I still think LPG is a safety hazard in a bad accident as it is a gas at air pressure. Diesel is much less imflammable even than petrol and I do not think they can be converted to LPG due to the high compression ratio.
However the CSMA motoring magazine has been trialing it for petrol conversion and is very impressed with the economy.
If it became really popular the government would tax it so heavily the incentive would dissapear. At the moment you only lose a large portion of your boot space and cannot travel by Eurotunnel.
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I think Diesel car mag recently carried a short piece about this. Apparently you can mix up to 10% LPG with diesel without too much modification.
However here is a comment from the lpgas website, www.lpga.co.uk
"Diesel engines, on the other hand, are much more difficult to convert as the compression ratio has to be altered and an ignition system added. It is generally only practical to consider conversions of very large diesel engines and, at the smaller end, it is more economical to purchase a petrol engine of the appropriate size and convert this."
Personally IMHO I consider its not worh the hassle, as presumably the driving force is to reduce xposure to tax. If LPG really takes off old Gorders will only wind it up.
You can run diesels on 100% LNG without too much modification, but the availability of that, plus the difficulties of storage, as its stored at well below zero means its only suitable for really big fleet operators, and I dont think too many have taken it up, if any!
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Modified large diesel engines operating on natural gas or landfill gas are commonly used as drivers for electricity generation. But Stuart is right - the conversion is not simple. Depending on the fuel, a spark ignition system may need to be added, and/or the gaseous fuel may need to be supplemented with a proportion of diesel fuel. The economics of conversion for a small engine would need careful consideration. Also, if it needs fundamental changes to the engine such as an altered compression ratio, then the ability to run on diesel alone may be lost. This could be a real snag at present given the limited number of autogas filling stations. A petrol/LPG vehicle can still run on petrol alone.
Regards
John
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LPG CNG & LNG require a spark to ignite them in the engine, so I cannot see how LPG can be mixed with diesel or how a diesel engine can run on LNG without serious modification.
So as LPGA says its only worth considering converting a petrol car. Kits to convert a diesel may exist but unless for something the size of a bus is it worth it, why not find a donor petrol engine. Finally the savings of LPG over diesel aren't that huge so the time to recoup costs will be much longer than for a petrol conversion. see www.easternautogas.co.uk/save.html
FWIW On a modern petrol injection engine the conversion consists of a box of tricks to read the signals that the engine management is sending to the injectors, while keeping them closed but fooling the ECU that they are working. A tank (which if is spare wheel well does not take up a large proportion of boot, maybe 10%), a device to convert the liquid to a gas in a controlled on-demand way, and a device that looks similar to a gas ring which fits between the air filter and the inlet manifold. I know a guy who has converted an old carb Range Rover himself and maintained it wasn't difficult.
As for horror stories, HJ has mentioned that Honda's don't convert well, and place where I had mine done have had a problem with a Honda conversion.
HTH
Jon
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Sorry, I forgot about this in my earlier post, re the safety bit.
There was some work done in the late 70's/early80's @ the HSE's explosive place up near Buxton to see if a LPG tank in an auto accident would explode.
I seem to recall they set fire to a car with a fullish tank to see what would happen. There was no explosion as the tanks are provided with a safety vent which is supposed to vent the gas in a controlled way, but there was a bleeding big jet of flame thrown out!
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My worry with any gas fuelled car would be that a leak or venting e.g. in hot weather, inside a garage, particularly if integral with the house, would have the potential to go bang when you walked in and switched on the light.
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Millions of people have gas in their homes, not that many of them go "bang" and if they do it's normally through their own mistake (i.e. leaving unlit gas rings on).
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My tank has an air tight box that covers the filler / fuel line hole in the tank that is vented to the outside of the car. In addition there is an overpressure vent if the tank were to be compressed or suffer extreme heat. The tank can only be filled to 80% of its physical volume so that allows quite a bit of room for expansion. There are a series of interlocks so that the gas supply is cut under various circumstances eg engine stop. The tanks are issued with a certificate of conformance and need to be inspected again after 10yrs. The tank itself is immensely heavy/ strong and I suspect would remain intact after most of the rest of the car (incl petrol tank) had crumbled in a severe crash. People carry LPG cyclinders in their cars for camping and caravanning and can take these on Eurotunnel and leave them in their garage.
I think if there were an additional risk with LPG then it would be reflected in the insurance premium. There is no difference in the premium, so I conclude no additional risk.
Jon
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Think about it this way.
I own an H-reg Golf GTI and it is converted to LPG. The Golf has a plastic fuel tank, the LPG tank is a high quality pressure and impact tested pressure vessel.
On a rear collision my LPG tank merely buckles and the 20% capacity takes up some pressure and the rest is vented in a controlled manner. My petrol tank, however, full of benzene rich highly flammable unleaded is compressed as it is only plastic and the highly volatile fuel is either;
a.) Jettisoned over the car behind and onto their engine resulting in burns to their occupants or worse;
or
b.) It ruptures and hits my hot exhaust and takes the back of my car up in flames.
Think about it.
Also, if any government is going to hit LPG it will have to raise the duty by nearly 50p/Litre in one go??? Come on, get real. Also, duty is fixed until 2003 and my conversion will pay for itself in 8 months.
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I read somewhere that one byproduct of refining LPG is ... Diesel. If this is true, then why bother converting diesels to LPG (since modern diesel engines, with particulate traps, are cleaner than petrol engines anyway)? And in any case, we should be using Biodiesel, which is far, far better for the environment than LPG, which is still, after all, a fossil fuel. Maybe the oil companies are scared that widespread use of Biodiesel would break their control of the oil supply and therefore don't encourage it. Or maybe I'm paranoid.
Chris
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Where can I buy biodiesel in the Essex/Herts/ East London area?.
And if not, why not?.
The answer seems to be that it is not commercially available and is unlikely to be for many years.
(There is an earlier discussion on this issue.)
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No - small diesel engines cannot be converted to LPG operation - I've tried it and it don't work!!! Just makes the engine sound a tad rattly.
In reply to the safety of LPG, I personally would rather have an accident in an LPG fuelled car rather than a car with a flimsy tank of petrol. Have any of you guys actually seen/lifted an 80 litre LPG tank? It is a tested & certificated pressure vessel similar to that of an air compressor, pressurised to 160psi, if my memory serves me right.
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