By EWAN KENNEDY
30 October 2006

Holden now offers the option of a dual-fuel engine, operating on petrol and LPG, in some Alloytec V6 engines in the new VE Commodore range.

Liquefied Petroleum Gas (LPG) is a clean burning fuel with major advantages in reducing emissions. Studies show that LPG causes almost 20 per cent lower global warming over its full production cycle.

Interestingly, Holden has taken the opposite route to Ford. Ford has had the option of a LPG engine for some time, but sells it as a dedicated LPG engine, meaning it only uses the one fuel.

The argument from Ford is that building an engine to work on two fuels necessitates a compromise. Holden claims it has minimised the compromise to the extent that its dual-fuel engine is a viable proposition.

Holden has developed a sophisticated system that uses a sequential vapour gas injection (SVGI) to inject the gas directly into the combustion chambers. It’s done in a manner similar to petrol injection and uses the engine’s electronic brain to control the system.

The result is that the Holden engine gives up to 175 kW when running on LPG and retains its previous output of 180 kW when fuelled by petrol.

Fuel consumption isn’t particularly good when running on LPG. Holden has measured it on the official driving cycle at 16.0 litres per hundred kilometres, considerably up on the 10.9 litres per hundred for the standard petrol engine.

Note that the LPG engine’s consumption when running on petrol is 11.7 litres per hundred kilometres. Holden says the additional fuel use over the 10.9 of the full-petrol engine is due to the added 100 kg of the LPG tank and lines. But some of it may be caused by a loss of efficiency due to compromises inherent in a dual-fuel engine.

You can opt for whichever fuel is selling at a favourable price when filling up. Most drivers should be able to get the Commodore to cover over 1000 km on the combined fuel supplies.

The LPG engine is also sold with the VZ Commodore Executive and Acclaim station wagons as well as in the Commodore ute. These models are carryover versions of the old VZ series and will sell alongside the VE sedans for some time yet.

The additional cost of the dual-fuel engine in a Commodore is $3900. However, private buyers are eligible for the $2000 government rebate as technically speaking the new fuel system is added after the vehicle has left the factory. The work is done at the HSVi facility. If it had been carried out in the Holden factory the rebate would only have been $1000.

Boot capacity is cut by about a quarter due because of the bulk of the LPG tank. However, the remaining space is well-shaped and still capable of carrying two large suitcases one on top of the other.

Our initial driving impressions of the dual-fuel Commodore are favourable. Few drivers will be able to tell which fuel the engine is using and the engine has a smooth refined feel under all circumstances. The engine always starts on petrol as it’s easier that way, then runs on LPG when the engine is ready for it.

We found the warning beeper that lets you know the engine is running on petrol, when you have selected LPG, rather irritating. The engine runs on petrol until the coolant reaches a temperature of 45 degrees.