LPG
What is LPG ?
Liquefied Petroleum Gas, also known as Propane, is widely used for BBQ’s, caravan cookers, patio heaters, catering wagons etc etc . It comes in red bottles and is notably supplied by Calor although there are many others. It is distinct from the other common bottled gas, Butane which comes in blue bottles. Most gas conversions in the UK use Propane. It is possible to use Butane, but due to its higher boiling point it is more useful in warm climates and for summer use.
How does an LPG generator conversion work?
LPG conversions for portable generators are a little different to the conversions used in motor vehicles. LPG converted cars feed liquefied gas to an evaporator that then feeds to a regulator/gas controller. This evaporator is not necessary for small stationary engines as they can draw the vaporized gas straight from the top of the Propane bottle without the risk of the liquid splashing around and entering the regulator. Gas is fed through a standard 37mbar Propane regulator such as you might have for your caravan or BBQ and then into a gas controller which controls the rate at which gas is fed into the engine. Inside the gas controller is a large diaphragm that responds to the pressure pulse generated by the induction stroke of the engine. This pulse travels up the same pipe that feeds gas to the carburetor, acting upon a large diaphragm in the gas controller which in turn opens a valve allowing the regulated gas supply to escape through the controller to the engine. The mixture of gas to air is determined by the size of a jet that is usually located at, or close to, the carburetor.
Introducing the gas to the carb
Feeding the gas to the carburetor can be accomplished in two ways
Collar method:(dual fuel)
Using an aluminium collar situated between the air filter and the carburetor allows the carburetor to remain unmodified and still capable of running on petrol if desired. The collar has a pipe connection in the side that usually contains the gas jet. The collar is designed with a slight constriction to maximize transmission of the pulse created by the induction stroke of the engine without acting like a choke and effecting the mixture when the machine is running on petrol. It is of such a thickness that it usually requires longer carburetor mounting studs or the use of specially adapted nuts to secure the whole arrangement. On some machines, particularly those in the EM range and the EU26i and EU30is, the inclusion of the collar results in the air filter either hitting against the frame of the machine or making the air filter very difficult to access.
Spud method. (LPG only)
The spud method requires the replacement of the main jet and emulsion tube with a combined pipe connection and jet called a spud. The main jet and emulsion tube are removed altogether and the spud screwed in their place. This renders the carburetor unsuitable for petrol operation but it is much simpler to fit than the collar method and requires no modifications of the frame and studs and no awkwardness when accessing the air filter. Spud is probably an acronym for something but who knows what? so if you want to make one up, I’ll go with your version as mine is just daft. Screw Pipe Under Dere.
Advantages of LPG conversions
Economy
Running on LPG is cheaper than using petrol. How much cheaper depends on what size bottle you buy. Running from a 47kg bottle will roughly halve your fuel costs over petrol. The economies diminish with bottle size and once you get to the 13kg bottle they pretty much disappear. Economy is not the only reason to run on LPG
Reliability
If a machine is likely to remain idle for long periods, as back up generators do, then the chances are that any petrol contained within them will degrade and block the carburetor making it unusable when required. LPG does not have this problem. An LPG machine can remain idle for years and still start perfectly when called upon. LPG has no decay products to block a carb or hinder its operation. The bottle containing the LPG is sealed so there is no danger of degradation by evaporation
Safety
LPG is seen as being less of a fire hazard than petrol or diesel as there is less danger of a spill. This is particularly true in boating applications and marinas where a spill of diesel or petrol can spread rapidly across water and endanger many vessels. Propane gas is heavier than air so it is important to ensure adequate ventilation in the floor where lpg is used or stored.
Acceptability
Many event organizers will no longer allow the operation of petrol and diesel generators at their events and insist upon LPG due to its decreased fire hazard and less noxious fumes. This is a trend that is on the increase and is likely to become standard practice in time.
Operation of LPG converted generators
Some types of gas conversion require starting on petrol and then a switch over to LPG. The best way to operate conversions that require starting on petrol is not at all. Such conversions are a failure from start to finish and should be abandoned at the earliest opportunity. A proper gas conversion will start easily from cold. Gas conversions require no choke. For machines with auto choke, this must be disabled (via a switch if it’s a dual fuel system). For conversions with a primer button, a quick press of the primer introduces a shot of gas to the carburetor and the machine will start as easily as if it were operating on petrol. To stop the machine the supply is shut off, either by turning off the gas bottle or in the case of Beam controllers by the associated shut off solenoid valve. The usual ignition switch or stop switch method of stopping the machine is to be avoided where possible as it leaves unburned gas in the engine which will smell in storage and transit and may also cause a backfire when the machine is restarted
Fuel consumption of LPG converted generators
Every machine will have a slightly different characteristic but, as a rule of thumb, an LPG converted machine will use 0.4kg of LPG for every kw/hour of electricity generated.
Effect of LPG conversion on longevity of the machine
When a petrol engine ejects burned gases from the cylinder, it opens the exhaust valve and the gases are forced out of the exhaust port by the rising piston. With the exhaust valve open, a small part of the valve stem is exposed to the hot gases and any oil on it tends to be evaporated away. Petrol contains additives that help to improve the lubrication of this exposed portion, LPG does not. For this reason, LPG machines tend to wear the exhaust valve stem and it’s guide more quickly than petrol machines. In Honda engines the lubrication delivered to the valve gear is very generous and the wear negligible. In other makes such as Robin and Chinese machines, the effect can be more pronounced. It may be worth adding an oil improver to aid the lubrication of the valves. In any case the cost of replacing an exhaust valve and valve guide is insignificant compared to the economies of running on LPG.
Additive systems are available designed to protect the valves from this extra wear but in my opinion the extra wear is so minimal that in most cases it can be safely discounted.
Spark plugs and ignition coils
The air/ LPG mix in gas converted machines has a higher electrical resistance than the air/petrol mix in petrol generators. This results in higher voltages being generated in the ignition circuit and possible overheating of the spark plug or ignition coil. To counteract this effect the spark plug gap is reduced as much as possible (to about 0.4mm). Iridium type spark plugs that have conical electrodes are designed to further reduce the ignition circuit voltages. As Iridium spark plugs are very expensive it is probably more economical to reduce the gap on an ordinary spark plug and accept that they will need replacing more often than the plug on a petrol machine. In any case, whenever an LPG machine starts to misbehave the first thing to do is to change the spark plug and check that the gap is reduced to about 0.4mm.
Our LPG Services
We provide the following types of services to cater for your LPG needs for domestic and industrial purposes:
Sales and Service of Cylinders & Accessories.
Cylinder Installation.
Bulk Gas Supply
General LPG Solutions.
Specialised Solutions.
LPG Consultancy Services
LPG Generator Conversion
We are closer to you than you think
We are just a telephone call away from you. .
Versafusion Global Services is right here for you.
Call us on: +234 909 1474 884 or send us a message on WhatsApp.
Our Storage Containers
BBQ & Home Storage
We supply the following types of BBQ & Home storage containers: 3kg, 4kg, 5kg, 6kg, 9kg, 14.5kg and 18kg Home: 45kg, 50kg, 90kg, 210kg, 500kg, 700kg and 1000kg.
Bulk Storage
We also install and provide services for large and industrial containers such as Above-ground tank and Below-ground tank.
