Diesel to LPG Conversion (1 Viewer)

Steve304

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Hello Funsters,

Sorry to ask this question as it might be daft, but is it possible to have a Fiat Ducato based motorhome (130 multijet engine) converted to run on LPG instead of Diesel?

If so, how much is the approximate cost and is there any change in performance?

Thanks for any help on this.

Steve
 
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I don't subscribe to the 'Go LPG' websites conclusions regarding mixing LPG with diesel.

They say it's not viable, but it's been done in the US with trucks for years.

It's also available on UK trucks with many benefits such as smoother running, better economy and improved power and torque.

It's proven technology and can't be dismissed out of hand in the way that website suggests.
 
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oldun

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I don't subscribe to the 'Go LPG' websites conclusions regarding mixing LPG with diesel.

They say it's not viable, but it's been done in the US with trucks for years.

It's also available on UK trucks with many benefits such as smoother running, better economy and improved power and torque.

It's proven technology and can't be dismissed out of hand in the way that website suggests.

Can you suggest some article that are available supporting this view?

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laneside

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Three years ago we did extensive tests adding LPG to a diesel engine with limited success, yes we could achieve more power as tested on the rolling road at Blackburn College of technology.

The black smoke from the exhaust was totally unacceptable at anything above mid range revs and no matter how we did the adjustments we never achieved a penny saving on fuel.
 
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Steve

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I have been running a 200 tdi disco WITH lpg for 3 years now runs and pull like a dream. But the question was can you run it ON lpg the answer is NO but with lpg YES approx. 10%.
Steve

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enery8

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One of our local councils converted their diesel dustcarts on LPG but changed them back after a short while, don't know why however.:Doh:
 
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Occasionally drove a Foden artic for Warburtons bakery a few years ago. I don't know exactly how the system worked but the LPG kicked in automatically at some stage and then proceeded to run like a pig.Luckily it had a manual override.
 
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Interesting thread but one asks Why would you?

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Steve

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Interesting thread but one asks Why would you?
That is easy to answer, 50% extra power without any expensive bolt on bits, ie bigger turbo, different cam, ported head and so on. But..... there is always a but if you don't know what you are doing you may see the inside of the engine on the outside:Sad:
 
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That is easy to answer, 50% extra power without any expensive bolt on bits, ie bigger turbo, different cam, ported head and so on. But..... there is always a but if you don't know what you are doing you may see the inside of the engine on the outside:Sad:

Well according to these guys in a very comprehensive review it can`t be done, http://www.go-lpg.co.uk/diesel.html.
 
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Steve304

Steve304

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Interesting thread but one asks Why would you?

::bigsmile: I'm not saying that I would, even if it was possible, but simply exploring the options:- LPG, Chipping or remapping. Latter two put me off because of possible long term damage to engine, etc., as well as varied opinions of expected benefits claimed by suppliers.

At the end of the day, I'm more than happy with the performance of my van with respect to acceleration and torque, but a little bit disappointed with the overall mpg (22-24) and wanted to see if there was a cost effective way to recoup initial outlay of any modification. For example, the chipping option would pay for itself after about two years use in my case.

Steve
 
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which bit are you reading? the conversion to lpg or running with lpg?

Well the whole page but this bit in particular.

Overall Conclusion

Above it has been shown that niether true conversion of a Diesel engine nor the mixing (Dual fuelling, Fumigation) of LPG with Diesel give economic benefits large enough to make either choice worthwhile for the average motorist. With current LPG and Diesel technology as it stands, it would be more economical to simply remove the Diesel engine and fit a Petrol equivalent, which answers our original question -

'Can Diesel engines be converted to run on LPG?'

The answer, to date, is a qualified 'No'.
 
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Steve304

Steve304

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I have been running a 200 tdi disco WITH lpg for 3 years now runs and pull like a dream. But the question was can you run it ON lpg the answer is NO but with lpg YES approx. 10%.
Steve

So this system is a hybrid then? Any information as to where I might find any more details?

Steve

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icantremember

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I don't know if you plan to use the Channel Tunnel anytime with your m/h but as you may be aware lpg powered vehicles are banned and I assume a hybrid diesel/lpg would also fall foul of their regulations.
 
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Steve

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Well the whole page but this bit in particular.

Overall Conclusion

Above it has been shown that niether true conversion of a Diesel engine nor the mixing (Dual fuelling, Fumigation) of LPG with Diesel give large enough to make either choice worthwhile for the average motorist. With current LPG and Diesel technology as it stands, it would be more economical to simply remove the Diesel engine and fit a Petrol equivalent, which answers our original question -

'Can Diesel engines be converted to run on LPG?'

The answer, to date, is a qualified 'No'.

We are not talking economic benefits! just good old extra grunt when you need it. like towing then you turn it off. You can not get a diesel engine to round wholly on lpg have you got this yet? you can get them to run with lpg but the reason is to get more power that is all.
 
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We are not talking economic benefits! just good old extra grunt when you need it. like towing then you turn it off. You can not get a diesel engine to round wholly on lpg have you got this yet? you can get them to run with lpg but the reason is to get more power that is all.

I`ll tell you what I have got It`s not worth doing that is what I have got.
There are currently two ways of using LPG as a fuel for a Diesel engine;

1. To truly convert the engine by reducing its compression ratio and provide it with spark ignition.


Lack of Spark Ignition

Diesel engines do not have this.

Spark ignition can be provided in several ways but they all amount to the same thing.

The most effective is to remove the cylinder head and machine spark plug holes into the places where the Diesel injectors were sited. This is only possible if there is enough 'meat' in that position. If not, the spark plug holes may have to be placed elsewhere in the combustion chamber. The existing holes for the original Diesel injectors may either be plugged or perhaps be used for direct LPG injection. Leaving the Diesel injectors in place would bring no benefit when the next factor is taken into account......

Reduction of Compression Ratio

This must be done before the engine could be run properly on LPG or Petrol for that matter. Diesels often run at a compression ratio of roughly 16-1 (one of the reasons they are more economical) whereas Petrol and LPG engines need a ratio of around 10-1. One way of reducing the compression ratio is to fit some form of spacer inbetween the cylinder head and cylinder block mating surfaces in order to reduce the compression ratio of the engine. This may present problems of gasket sealing because two head gaskets would have to be used. Another solution is to replace the original pistons for redesigned ones with different (deeper) crown depressions, addressing the compression ratio problem but now the costs are beginning to escalate, and it must be remembered that when both of these changes (provision for spark ignition and reduction of compression ratio) have been made, the engine isn't a Diesel any longer.


Design Limits, Stresses and RPM

Although the Diesel engine is relatively slow-revving and produces its maximum torque at lower RPM than a similar Petrol version, this is not the case when it is converted to run on LPG. The revised engine has to'rev' more when running on LPG because its maximum torque has been pushed higher up the rev. band. This can bring new problems of reliability and longevity. Even if the 'top end' of a Diesel has been fully reworked, the crankshaft, bearings and connecting rods (to mention but a few components) will suffer higher stresses at increased RPM necessary when running on LPG. Mechanical breakdown may result in far less time, whilst increased wear and reduced component life are certain. FinaIly, note that in all of the above cases the converted engine will cannot be a true Diesel or even a dual fuel engine as it will have lost its higher compression ratio and the means to inject Diesel.

Conclusion

The above factors combine (along with many others not discussed here) to make actual conversion of most Diesel engines uneconomic. It would be simpler and quicker to fit a Petrol engine.


2. To mix LPG with the existing Diesel fuel before induction (Fumigation, not Conversion)


Various attempts have been made to achieve this with varying amounts of success. Go LPG! have examined many systems and installations and after much consideration have come to this conclusion;

None of the LPG / Diesel mix systems examined have resulted in Diesel consumption being reduced by more than 25%. Those savings made must also have LPG costs (for the LPG that replaces some of the Diesel fuel consumed) subtracted from that 25% saving. This results in final savings of only the low teens of %, or thereabouts.

There are other problems to consider as well - The unmodified Diesel engine was relatively slow-revving, producing its maximum torque at lower RPM than a similar Petrol version. This is not the case when it is converted to run on Diesel and LPG mix. The revised engine has to'rev' more when running on Diesel / LPG mix because its maximum torque will have been moved higher up the rev. band. This can bring new problems of reliability and longevity. The crankshaft, bearings and connecting rods (to mention but a few components) were all designed to rev. at a lower rate. These components will suffer much higher stresses (stress increases at the square of RPM) at the increased RPM necessary to get sufficient torque when running on LPG. Mechanical breakdown may result in far less time, whilst increased wear and reduced component life are certain, which answers our original question -

'Can Diesel engines be converted to run on LPG?'

The answer, to date, is a qualified 'No'.

To get that good old extra grunt the smart idea is to have a bigger engine.

End of.

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