Chevrolet unveils new Volt powertrain

GENERAL MOTORS has unveiled the petrol-electric drivetrain that will propel the next-generation Chevrolet Volt, ahead of the range-extended EV’s world debut at the Detroit motor show in January.

However there are no new details of the next Volt’s styling to follow up the closely cropped teaser image of the car’s tailgate issued in August.

As for an Australian debut, Holden senior manager of product communications Kate Lonsdale said the company was “not in a position to talk about future product” so it is unclear whether a new version of the slow-selling range extender will be included in Holden's model line-up.

“Needless to say, we review all products available to us through the GM network but do not have any announcements to make regarding Volt or new powertrains,” she said.

Redesigned from the ground up, the new drive system is claimed to suffer less noise and vibration, deliver swifter acceleration and provide greater electric-only range and lower fuel consumption in range-extender mode due to improved efficiency.

New battery cells developed with LG Chem achieve a 20 per cent greater power density than before, enabling GM to reduce the number of cells from 288 to 192, position them lower in the pack for improved centre of gravity and reduce overall pack weight by 13kg.

The new electric drive unit is claimed to be up to 12 per cent more efficient and 45kg lighter than the one it replaces, with two motors sharing the load and improving electric acceleration by 20 per cent.

It now integrates the power inverter module, which manages power flow between the battery pack and electric motors, to improve efficiency while reducing size, weight and build complexity – however GM is holding back electric range estimates until the official unveiling at Detroit.

Ending speculation that the new Volt would use a three-cylinder petrol engine for its range-extender, GM has announced it will use a 1.5-litre four-cylinder from the company’s new EcoTec family, announced in March.

Larry Nitz, executive director of GM Powertrain’s electrification engineering team, said the choice of larger engine “assures owners they can go anywhere, anytime without having to worry about whether they will have enough power … it’s all about keeping the promise that the Volt is a no-compromise electric vehicle”.

Volt owners – who together have accumulated more than 966 million kilometres of electric-only driving since the model’s North American launch in late 2010 – have been a major contributor to the research and development phase of the new car’s drivetrain, through data collected on their driving behaviours.

Global head of Chevrolet Alan Batey said more than 80 per cent of journeys by current-generation Volt drivers are completed without engaging the petrol engine.

“We’ve used their real-world experiences to define the next generation Chevrolet Volt … by putting our Volt owners at the centre of what we do and leveraging our electrification engineering leadership, we’ve been able to raise the bar and will exceed their expectations with the new Volt.”

GM carried out a 30-month study of 300 Volts in California that revealed many owners were able to exceed the car’s official 56 kilometre electric range on a full battery charge, with around 15 per cent exceeding 64km.

“The current generation Volt’s battery has proven to provide our owners exceptional performance when it comes to quality and reliability,” said Mr Nitz.

“It would have been simple for us to tweak our existing battery to provide nominally increased range, but that’s not what our customers want, so our team created a new battery system that will exceed the performance expectations of most of our owners.”

Addressing the Detroit Economic Club on Tuesday, GM CEO Mary Barra said the new Volt “will represent a significant leap forward in technology, design and overall refinement”.

“It will store more energy in its battery pack with fewer cells, yet go further on a charge. It will accelerate faster. And the car's gas generator will come from an all-new GM engine family and use even less fuel.”

To the end of September this year Holden has sold 47 Volts, compared with 89 for the same period in 2013, a decline of 47.2 per cent.