A wheel-motor series hybrid is indeed coming up from Volvo, but don’t hold your breath. Apparently something very big could be in the wings, some sort of next generation hybrid or e-flex technology, making the announcement of the “Recharge” concept car – a wheel-motor series hybrid – not the biggest story Volvo intends to break this year. And with that titillating tidbit, back to Volvo’s car of the future, the car that Science Officer Ichiro Sugioka, based at Volvo’s think tank in Southern California, says “will be probably coming out in ten years at the earliest.” He said the series hybrid using in-wheel motors was “definitely not our next hybrid,” and “we like to keep the surprise.”
With a prototype car already operating in Sweden, using a C30 body, the most interesting revelation that came out of our lengthy conversation today was how far in-wheel motors have advanced, and the advantages using them imparts to the overall vehicle design.
|VOLVO’S WHEEL MOTOR SERIES HYBRID CONCEPT CAR|
|Balances the grid, buys, sells and stores electricity.
Not just a car, but your very own micro-utility company.
A criticism of in-wheel motors is that their centrifugal inertia due to the weight of the motors makes handling the car difficult. But PML Flightlink, a maker of in-wheel motors, has supplied modular in-wheel motor-generator components that Volvo engineers have pieced into a unit that delivers, for the first time according to Sugioka, “enough torque to deliver normal performance but still fit into the rim of a normal tire.” Up till now, vehicle electric motors required reduction units to achieve sufficient torque for starting and accelerating. This motor’s powerful 1,000 newton-meters of torque allows much higher regeneration efficiency as well as braking ability. And in turn, the superb regenerative braking of the motors makes it possible to replace the entire disk brake assembly with much lighter ring brakes.
The weight in the wheel-motors is further offset because the wheel bearing housing has been replaced by the motor casing, and a lot of the suspension components are combined into the wheel motors. Using lighter rims and lighter tires also reduces wheel weight. And, of course, with motors possessing this much torque, the otherwise mandatory reduction gear is eliminated, further reducing weight and also improving drive-train efficiency. Sugioka acknowledged “there is validity to the weight issues,” but clearly didn’t think they were insurmountable.
Volvo has a lot of experience with series hybrids, having first tested series hybrid prototypes back in the 1990′s. But in ten years, along with having wheel motors and series hybrid technology, cars will be really, really smart. In ten years cars will function as decentralized electricity storage units living on the grid, leveling demand, buffering surge, storing intermittant surpluses such as wind energy, when they aren’t being driven around. “We have to talk with all the stakeholders,” said Sugioka, “we need to get the utilities engaged to reinvent the business model for cars in general.”
Another interesting spec discussed today was the dedicated generator, which is charged onboard by a standard 1.6 liter four-cylinder gasoline engine. The generator is also built using components from PML Flightlink. Sugioka stated the 50 kilowatt generator was so small and flat, it could be placed directly behind the standard gasoline engine and would take up considerably less space and weight than the transmission which is removed. On gasoline only, the prototype gets 44 miles to the gallon.
|It’s all about efficiency.
A young Elephant Seal – spring equinox, 2008
Piedras Blancas, California
“My responsibility is on things that are pretty far away,” said Sugioka, which means his team is spending a lot of time on wheel-motors and not a lot on batteries. The prototype is currently using an oversized battery pack that is located in the car’s truck, for testing purposes. And even with the heavier battery pack, this car is sipping 200 watt-hours per mile, or 5.0 miles to the kilowatt-hour. The battery is spec’d at 12 kilowatt-hours of usable storage, hence a 100% battery range of up to 60 miles.
As for zero to sixty and top speed, the prototype has artificial limits – the engineers want to keep the motors cool until they’ve completed a power management system. The intelligence of cars is a revolution happening at the same time as the greening of cars. The smart electric vehicle will be a working, self-sufficient vendor for the owner, collecting money from utilities for storage and buffering services, as well as from buying energy low and selling it high. Eventually smart cars will greatly help level utility rates. Smart cars will respond to wireless commands, and automatically customize the driver experience per operator.
Every day brings us closer to freeway capable personal transportation appliances that are smarter, cleaner, and greener than ever, as we see new innovations from in-wheel motors to the e-flex platform, and Volvo, known for some of the safest cars in the world, has been preparing for the electric age for a very long time. Surely we are at the tipping point of the next automotive revolution, that the wheel-motor series hybrid announcement by Volvo just this January, given the car on the street could be ten years away, might just be some sort of marketing dept. derived head fake, a diversionary tactic, so nobody will scoop the new vehicle they are about to unveil…