Wednesday, 25 May 2016
BMW’s eAxle nod gives others the push
BMW is the industry benchmark. It is every vendor’s aim to have BMW heading its reference list.
And so it is at UK transmission specialist GKN, although it was Porsche which gave the technology the initial spurt. Now other automakers are set to follow the trail struck by the Munich-based automaker.
As production gathers momentum at the company’s eDrive production facility in Bruneck, Italy destined for the first application, namely BMW 2 Series Active Tourer PHEV, so the line will gearing up for other OEMs.
GKN Driveline claims several new C-Segment vehicles will offer the option of plug-in electric all-wheel drive using the British company's latest electric axle drive (eAxle) technology.
The eAxle is an evolution of systems developed for hybrid supercars employing electric all-wheel drive to boost performance and efficiency.
With GKN having secured orders for a major global platform it was only to be expected others would not be long before they followed suit.
GKN Driveline chief executive Phil Swash confirms the close ties GKN has been able to establish with BMW.
“From the i8 to the 2 Series Active Tourer, GKN’s work with BMW reflects our position as the development partner of choice for the coming wave of plug-in hybrids with eAWD,” said Swash.
“Our total focus on driveline innovation, our unmatched expertise in all-wheel drive and our 14 years of production experience in eAxles are now making eAWD viable in smaller, more affordable vehicles,” claimed Swash. “GKN Driveline continues to bring the future of eMobility into the here and now.”
GKN says its new electric axle drive has been “optimized” for compact car applications. The lightweight single-speed design has a transmission ratio of 12.5:1, reducing the electric motor speed in two stages.
The system can generate up to 2,000Nm and 70kW of additional torque and power – adequate for a vehicle’s pure electric mode to achieve speeds of up to 125km/h.
It can provide an all-wheel drive (AWD) mode that can accelerate a vehicle “considerably faster” than conventional mechanical AWD systems, according to GKN.
The complete unit weighs 20.2kg and has a length of 457mm, a width of 229mm and a height of 259mm, assisting packaging and installation in confined spaces.
When hybrid operation is not required, the e-machine can be disconnected from the driveline by an integrated disconnect device, which uses an electromechanically actuated dog clutch. This minimizes rotating losses at higher vehicle speeds when disengaged.
GKN says it has “optimized” gear and bearing arrangements for efficiency, NVH and durability, no doubt driven also by BMW’s demanding requirements.
Consequently, precision engineering throughout, including a low backlash, high performance transmission differential and case ensures transitions between pure electric, hybrid and ICE modes appear “transparent” to the driver.
The latest generation of GKN eAxles offer a step forward in terms of performance, size and cost. For many front wheel drive vehicle platforms, it is now more simple effective to electrify the rear axle than to bolt on a hybrid module to the main transmission.
GKN Automotive president of engineering Peter Moelgg, claims GKN’s eAxle technology is “passing a key milestone” in its evolution at a time when “demand for all-wheel drive and plug-in hybrids is strengthening”.
He further claims the latest system “advances the business case” for electric all-wheel drive capability in hybrids.
“A number of automakers are introducing our technology on their premium models and starting to transfer eAxle hybrid versions of higher-volume models,” he adds.
eAxles can transmit electric torque directly to the vehicle’s wheels, providing more immediate response and dynamic acceleration. Input speeds of 14,000rev/min are now possible and are expected to exceed 20,000rev/min in the next few years – far higher than is possible with hybrid transmissions – as demand for smaller systems emerge.
GKN launched its first eAxle applications in 2002. The company was awarded Official Porsche Technology Partner status for its contribution to the plug-in hybrid Porsche 918 Spyder program. It launched the world’s first two-speed eAxle in the plug-in hybrid BMW i8 and also supplies the eAxle on the Volvo XC90 T8 Twin Engine PHEV program.