2012 Jaguar XF engineering: did you know?
Jaguar did not just reveal the science behind the styling of the 2012 XF when I visited Whitley a few weeks back: it also provided a tech briefing, too.
It’s this that the Jaguar engineer who took me out on the test run was so proud of. Styling is great, but to engineers, it’s below the surface where you see the real nitty-gritty.
Needless to say, they’ve been as busy as their colleagues wearing the designer jeans and Paul Smith tops. With a tweak of the engineering-spec shirt and tie, XF project engineering manager Paul Alcock took us through what makes the 2012 XF one of HIS most significant facelifts, too.
V6D benchmark for 2.2D
‘From the beginning, we wanted refinement comparable to the V6D. This was the bar that we set at the befitting of the project.’
ZF adds ability
With so many ratios from the 8-speed ZF gearbox, the new XF could potentially be perpetually shifting gear (7th and 8th are both overdrives). Good job there’s a multiple downshift facility, allowing it to switch from 8th to 2nd if necessary. ‘Shifts are faster, there’s a larger ratio spread and the torque convertor locks up at a lower speed.’
The torque convertor disengages when stationary, to improve efficiency. This allows the stop-start function to operate in D, not N.
More than 50 parameters are checked by the stop-start – feeds are taken from the cooling system, climate control, brake pedal pressure and so forth. There are no ‘chimes’, just an ‘ECO’ light in the rev counter – ‘to reassure drivers they haven’t stalled’.
The engine is also used in the Range Rover Evoque, but here, it’s rotated 90deg to a north-south layout – ‘giving challenges in itself’. It’s not the same as in the Range Rover, though: details stretch to a new (shallower) sump, which provides the necessary ground clearance for a Jaguar. ‘It’s made from a new material to reduce radiated noise.’
Reduced cabin noise
A twin-layer bulkhead reduces interior noise levels by up to 3dB. CFD has been used to optimise exterior components – ‘best in class wind noise’ comes from developments to the door mirrors that channel airflow away from the side glass.
Jaguar has a ‘target form noise’ test, which is what the driver’s outer ear picks up at 160km/h: in this, the Jaguar S-Type produced 31.0dB. The 2010 Jaguar XF was rated at 29.2dB, the 2011 model at 29.0dB – and the 2012 Jaguar XF? 27.6dB: a huge decrease on the logarithmic decibel scale.
Attention to detail beneath the 2012 Jaguar XF has seen castellated underfloor spoilers introduced, to stop airflow being ‘snagged’ by mechanical obstructions.
XFR budgeted for
Alcock was the man responsible for signing off the separate budget for XFR chassis development. He allowed the engineers to toil around the Jaguar test track at Gaydon in the search for the nuances that, he hopes, will make it a class-leader. Good man.
Adaptive damper availability has been stretched down the range: it was just offered on the XF 3.0D S… now, it can be had on 3.0D and 2.2D models. This pleases Alcock – more revenue for the firm.
Suppliers help add equipment
Jaguar worked with its supplier base to introduce new technologies: auto high beam assist, adaptive lighting, auto hazard lights under heavy braking, and adaptive cruise control with emergency braking.
The 7-inch touchscreen now has more shortcuts and more technical integration – iPhone has been introduced, for example. Jaguar has also tidied up the screen graphics and made it much easier to use: it’s a big customer touchpoint so greater usability here is always desirable.
Bonnet vents not all hot air
In the XFR, the bonnet louvres have grown. They ARE functional, too, releasing heat from the exhaust headers. ‘One of my favourite views is sitting at lights on a hot day and watching the heat haze shimmer waft out of them,’ said Jaguar design chief Wayne Burgess. I’m with you there…
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