With petrol in Australia starting to reach prices that require a re-mortgage on the house every time we visit the bowser, Holden has released a range of vehicles that are solely LPG (Liquid Petroleum Gas) fuelled. This has mixed economic benefits in that LPG, in Sydney right now (mid October, 2012) is around the 75 cents per litre mark. Sure, cheap to buy but with the lesser energy granted per bang, it requires more litres per 100 kilometres and, in some NSW towns for example, the cost of LPG ends up actually outweighing the cost benefit it would normally grant. Bega, down on the south coast of NSW, had LPG at 99.9c per litre over the last weekend of September. Still cheaper than petrol but to refill more often would cost more than its worth to use. In Perth mid September, it was around the 86c per litre mark. Why the disparity, given LPG is largely “mined and refined” on W.A.’s north coast and shipped from there, sold overseas, some say, at around 2c per litre…. Admittedly the main market for these cars isn’t rural areas (where it’s actually better suited) but normal, everyday suburban driving.
A Wheel Thing has been granted access to three Holden LPG vehicles; the Omega Sportwagon, SV6 sedan and Caprice. All are powered by a re-engineered 3.6L V6 engine, pumping and twisting 180 kW (6000rpm) and 320 Nm (2000rpm). (http://www.holden.com.au/vehicles/commodore/efficiency)
The Omega puts into perspective how base models have progressed by including passive and active safety such as airbags and ABS; communications such as Bluetooth and touchscreen tech; independent suspension all round, stuff not seen on the Commodore when it was first launched back in 1978, alongside the Torana and Kingswood. The normal petrol engines feature direct cylinder fuel injection which increases efficiency whilst decreasing emissions.
The LPG only powerplant uses a “vapour injection” system; chosen after extensive research by Holden engineers, against the liquid injection form, it was found that by using the vapour setup that economy was better whilst further decreasing emissions, plus allowed further engineering refinement with LPG specific fuel rails, injectors and injection manifold. The hardened valves and valve seats, again LPG specific for durability sit in the specially engineered heads. One of the targets the engineering team set out to achieve was emissions of less than 200 grams of CO2 per kilometre plus the vapour system lends itself to less mechanical issues, a must if used in rural Australia where the local Holden dealer may be hundreds of kilometres away. New pistons were included to cope with the higher octane rating of LPG whilst a re-engineered gearbox slots in behind the engine; it’s lighter and smarter to take advantage of what the engine can deliver.
Something noticeable from the rear, even on the SV6 and Caprice, is the single exhaust outlet. Designed with a twin muffler setup positioned mid body, the system is intended to aid refueling in hot climate conditions. Fed from a new header setup, this breathes out the leftovers from the vapouriser system, specially designed and programmed for the engine and the only system of its type used by a manufacturer in the world. The vapouriser itself takes the liquid, heats it to a vapour that is then injected.
Safety wise, naturally the engineering of the tank itself was critical to the success of the program. As LPG occupies more space than petrol, an 84 litre tank was designed, built from aluminuim, tested to within an inch of its life and neccesitated some chassis design changes. For weight distribution and for safety, the tank has been located behind the rear axle, also partly responsible for the single exhaust. The tank itself is aircraft grade extruded aluminuim with a multi cell construction. It’s also possibly the only original equipment tank fitted on a large scale by a manufacturer.
The Omega Sportwagon loses some rear cargo space with the spare wheel being transferred upwards but rides no differently. I did notice the test car felt more like a 3.0L engine, in keeping with that being fitted normally. There’s a slight delay on startup and a small hesitation on moving forward on acceleration however drives as if it was a normal engine. It was taken to Bathurst in conjunction with the Supercheap Autos Bathurst 1000 race and returned economy figures of around 11L/100kms with the country and suburban runs before being swapped for an SV6. As expected, the ride itself was comfortable, untiring whilst the interior design, although pleasant enough, is now really showing its age compared to the newer offerings available….VF can’t come quick enough.