BARRY PARK August 06, 2012
Replacing the big lump of lead and acid under the bonnet with a higher 48-volt system can bring fuel-saving advantages.
Cars could soon ditch the 12-volt battery for a 48-volt version - all in the name of fuel efficiency.
A British engineering firm believes it is inevitable that European car makers will have to adopt a 48-volt system that works much more economically with the stop-start technology used on conventional internal combustion engines.
Start-stop technology is used to switch a car’s engine off when it is stuck in traffic, saving fuel that is normally wasted, and restarting it as soon as the driver’s foot lifts off the brake.
However, car-based engineering group Controlled Power Technologies says the 12-volt system won’t supply enough power to run the stop-start system efficiently, and that a 48-volt system is better suited to the technology.
The higher voltage will also be useful to car makers needing to switch from engines powering components such as the car’s airconditioning, steering and braking systems, to electrically powered components.
Nick Pascoe, CPT’s chief executive, told SAE International’s Vehicle Electrification magazine that upping the voltage would particularly help diesel-engined hybrid systems, which could lower both harmful emissions and soot using the technology, as well as helping the engine to restart in half the time it takes a conventional 12-volt system.
There are benefits, too, for hybrid vehicles, with CPT saying the 48-volt system is also better at scavenging the electricity recovered using regenerative braking - particularly if the brakes are only applied for a short time - and also with low-speed driving.
According to Pascoe, the company is in talks with car makers who believe the 48-volt system could enable the development of new fuel-saving technology in cars.
Car makers including Mercedes-Benz, Ford and General Motors have already toyed with the idea of ditching the traditional 12-volt system in favour of a higher voltage.
The benefits to car makers include the ability to make systems such as power steering units and starter motors more powerful without the need to increase the amount of wiring needed.
In 2001, Mercedes-Benz even unveiled the Mercedes-Benz F 400 Carving, an open-top concept car featuring electronic ‘‘fly-by-wire’’ steering and braking, powered using a pair of 42-volt systems.
GM, on the other hand, has introduced a 42-volt system to work the electrically assisted steering of many of its larger-engined hybrid vehicles, many of which feature a fuel-guzzling V8 under the bonnet.