Can Diesel engines be converted to run on LPG!

[brunobanani]

Тъй като затвориха темата за метан на дизел намерих едно мнение от експерти за пропан-бутан на дизел.

За жалост се оказва, че това упражнение е почти невъзможно.

Колкото и налудничаво и смешно да звучи обаче в Германия продължават да работят и развиват системата DING (Direct Injection Natural Gas) за дизелови мотори и вече са достигнали до ниво при което не е необходимо по мотора да се правят сериозни модификации. Досегашните разработки както някой вече спомена позволяват смесването на 40% дизел и 60% метан.

Както се досещате без дизела няма как да стане работата по възпламеняването, но вече има мотори които се нуждаят само от 10% дизел за първоначалното микровпръскване и 90% метан.

Особеното при тях обаче е, че не могат да работят само на дизел, ако останете без метан за разлика от досегашните разработки, които на практика са Dual Fuel Engines...

Та един такъв хибриден мотор не е чак такава химера, защото комбинацията от добрите икономични качества на дизеловия мотор съчетани с екологично чистото метаново гориво е една алтернатива за близкото бъдеще.

Ето и темата за пропан-бутан на дизел, където вече положението е безнадеждно

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

This can be done 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 injectors used to be 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 injectors may either be plugged or used for direct LPG injection. In all of the above cases the engine will NOT be dual fuel as it has no means of injecting Diesel.

Some form of spacer must be fitted 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. Another solution is to replace the original pistons for redesigned ones with different (deeper) crown depressions, addressing the compression ratio problem, but the costs are beginning to escalate......

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 run on LPG. The engine must 'rev' more when running on LPG to produce maximum torque and this can bring new problems of reliability and longevity. Even if the 'top end' of a Diesel is fully reworked, the crankshaft, bearings and connecting rods (to mention but a few components) may suffer higher stresses at increased RPM necessary to get sufficient performance when running on LPG. Mechanical breakdown could result, whilst increased wear and reduced component 'life' are certain.

Sadly, the above factors combine ( along with many others not discussed here) to make the full conversion of most Diesel engines uneconomic.

2. To mix LPG with the existing Diesel fuel before induction.

Various attempts have been made to do this, and with differing 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 18% or thereabouts. Given the low overall savings achieved (to date) and the cost of conversion (equal to that of an injected Petrol engine conversion) many miles would have to be covered before any real savings are realised. This does not seem to be an economically viable alternative.

However, there are some other benefits apart from saving fuel cost. The Diesel engine becomes quieter and more responsive when using the LPG / Diesel mix. It starts a little more easily and gets up to optimium temperature more quickly. Harmful emissions such as Particulates and Carbon Monoxide are greatly reduced.

On purely a cost-reducing basis this system does not seem an attractive or useful alternative for the average Diesel motorist right now and it is hoped that research will continue. Hopefully a better solution will be found.

With current LPG 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 is a qualified 'No'

[Lube]

май това което съм казал ТАМ е било вярно...

и тази тема ще свърши като онази