All-New Dedicated Holden LPG Commodore

Holden’s dedicated LPG Commodore was the subject of an intensive and exhaustive engineering program that ensures a vehicle tailor-made for Australian conditions, with a raft of local engineering solutions that make this the best LPG Commodore ever produced.

Holden’s Program Engineering Manager for the LPG Commodore program, Brian McMurray, says the scope and exacting execution of this engineering program has ensured customers are buying a vehicle that is world-class for driveability, CO2 emissions and fuel running costs.

“The engineering team had three crucial targets for this program. To achieve less than 200 grams of CO2 per kilometre across the range, to ensure fuel running costs comparable to a small or medium-sized petrol car and finally, to ensure a seamless drive experience for customers familiar with a petrol Commodore,” said Mr Murray.

“I’m very proud to say that the team has achieved, or exceeded, those goals. After more than 1.3 million development kilometres and 78 testing and evaluation prototypes, the Holden engineering team has executed a no-compromise LPG experience.”

LPG injection system

At the very beginning of the LPG project, Holden engineers evaluated liquid and vapour-injection LPG systems. After preliminary research and building a proof of concept liquid injection prototype vehicle, it quickly became apparent that vapour injection was the only solution to achieving the program’s goals.

“Vapour injection provides lower fuel consumption and lower CO2 emissions compared to liquid, while vapour also uses fuel more efficiently with fewer pumping and parasitic losses,” said Mr McMurray.

“Vapour systems are less mechanically demanding and therefore better suited to the varying grades of LPG fuel found across Australia.

“Vapour is also best suited to the Australian climate, with more consistent start-up in hot climatic conditions.”

Powertrain

The heart of the LPG Commodore is the 3.6-litre, double overhead cam V6 engine, with four valves per cylinder. This engine has been designed to run solely on LPG and therefore has allowed for design optimisation in several key areas.

The entire LPG fuel system has seen significant development, with new fuel injectors, fuel rail and LPG fuel filter.

Specific fuel injectors have been developed, with these injectors target positioned within the engine to optimise fuel delivery – giving better performance, lower CO2 emissions and improved driveability and durability.

The fuel control system has also been optimised in the areas of fuelling, spark advance and cam positioning to ensure that the advantages of LPG are fully realised for lowest possible CO2 emissions and best performance and driveability under Australian driving conditions.

Additional highlights include hardened valves and valve seats to ensure long-term durability, while the heads and manifold are also designed specifically for the LPG Commodore to ensure optimised air flow and combustion.

As LPG contains a higher octane rating than petrol, new pistons of an optimised design have been used to raise the compression ratio to 12.2:1 to take full advantage of LPG fuel.

A particular highlight of the dedicated LPG Commodore is the new six-speed automatic transmission. Lighter, smarter and more refined, this new transmission boasts sophisticated control software that optimises shift patterns to provide outstanding driveability.

The end result is a world-class engine with excellent performance and outstanding fuel economy. Producing 180kW of power and 320Nm of torque, the dedicated LPG engine eclipses the outgoing dual-fuel LPG variant by 5kW and 2Nm. And yet the new LPG Commodore Omega sedan records 11.8L/100km on the ADR combined cycle, an improvement of 1.6L/100km – or 13 percent – compared to the dual-fuel LPG Omega sedan.

Depending on fuel prices, the Omega sedan will cost less than $1,300 per year in fuel to run, which is up to $800 a year cheaper than a 1.8-litre Toyota Corolla.*

Holden’s engineering work has ensured the entire LPG Commodore range has been awarded 4.5 stars by the Green Vehicle Guide, and exceeds “Beyond Euro 6″ exhaust emissions standards.

Combine these results with a range of more than 700km, and the LPG Commodore is a no compromise proposition, allowing customers the freedom and practicality of a large car without the large car fuel bills.

Additional highlights

Over the duration of the exhaustive LPG Commodore engineering project, numerous local engineering solutions were implemented by Holden engineers and suppliers. Several of these engineering innovations have been awarded patents.

Additional engineering highlights include the purpose-designed LPG vapouriser. This unit regulates the flow of liquid LPG, subsequently heating the fuel and causing it to vapourise, creating the vapour that is then injected into the combustion chamber. The vapouriser is another made-to-measure component, and is the only one of its type being used by an OEM manufacturer anywhere in the world on an engine of this capacity.

In order to use the vapouriser, Holden engineers had to create and execute new software to operate the vapouriser and integrate it into the powertrain system. This required unique code to be written for both the ECM and VCM management systems.

Spent exhaust gasses are managed through a specifically-designed exhaust system which is differentiated from the rest of the range by a single exhaust outlet, which also aids with refueling in hot climate conditions. This newly designed exhaust uses a twin-muffler system positioned mid-vehicle and is tailored to refinement, power and torque requirements for the LPG engine.

Refinement has also been paid special attention, with a specifically tailored noise and vibration package to ensure a pleasurable drive.

Safety

As with all Holden products, safety was an overriding priority throughout the LPG Commodore program. Like all VE Commodores, the LPG model goes beyond the mandated Australian regulatory requirements and scores the maximum five-star ANCAP safety rating while providing outstanding real-world safety.

With its incredibly rigid body structure with multiple load paths for maximum energy absorption in an impact, ESP standard on all models, as well as six standard airbags in every model, the Commodore remains one of the safest cars on the road today.

But the LPG program provided its own unique challenges to our safety engineering team.

LPG requires a larger tank than petrol in order to achieve a similar range, so to keep mass contained, Holden’s safety engineers developed a lightweight, 84-litre aluminium tank – which to our knowledge is the only mass-produced, OEM-equipped, aluminium fuel tank anywhere in the world.

In order to balance mass and weight distribution with our stringent safety requirements, the safety team relocated the tank rearward of the rear axle which was an intense engineering exercise in itself and required significant re-routing of the exhaust system among other modifications.

The tank itself is constructed from high-strength, multi-celled, aircraft grade extruded aluminium with strategically-placed additional aluminium protection plates.

The aluminium tank was the subject of intense research and development activity, including numerous simulated and physical tests of both the tank itself and in-situ within the vehicle in the form of nine barrier crash tests performed in-house.