Flybrid set to join Volvo arsenal

Volvo is set to use a flywheel-based kinetic energy recovery system (KERS) instead of batteries to salve range anxiety and save fuel in future hybrids.

Indeed, a flywheel-based generator system could be recharging plug-in hybrid (PHEV) Volvos’ battery banks in concert with conventional internal combustion engines within the life of existing models.

That’s the word from the Swedish company’s head of R&D, Senior Vice president, Peter Mertens.

Speaking at this week’s XC90 reveal in Stockholm, Mertens told motoring.com.au that flywheel systems could be in production within three to four years.

Volvo has been showing off prototypes of KERS-equipped cars in recent years — now Mertens is suggesting such technology matched to existing and new PHEV models is very close to production ready.

So-called ‘flybrid’ KERS systems effectively use powering up the flywheel as a regenerative braking system.

While Mertens would not elaborate, motoring.com.au understands Volvo is proposing a part mechanical system rather than the all-electric wheel motor/generator and powered flywheel ‘accumulator’ that Porsche pioneered in its 911 RS Hybrid racer.

The system favoured by Mertens features a series of gears driven from the rear axle that spin a vacuum-mounted carbon-fibre flywheel to speeds in excess of 50,000rpm. Computerised systems then harvest the flywheel’s energy to power an electric motor and or charge a conventional PHEV battery pack.

"Flywheels are still on our agenda and we’re working on that. And we absolutely still plan on bringing that technology into production," Mertens told motoring.com.au.

“It’s not an easy system to control but once you have, it’s a neat idea… With really relatively low cost,” he explained.

“It’s one of the enablers. It doesn’t give us big improvements [in its own right], but [incremental savings] here or there makes a big difference [overall] in emissions and fuel use,” he stated.

Volvo is “monitoring” fuel-cell development but Mertens says flywheels are a more practical way forward in the medium term than betting on significant technology shifts or big leaps in battery efficiency.

“It took us 100 years to get to lithium ion. I don’t see that quantum leap [in battery technology] coming quickly,” he opined.

“I’m also not so sure that putting consumer [electronic goods] 1.5-volt cells in thousands [sic] and adding 450kg to the base vehicle is the right answer either,” Mertens stated.