The Jaguar XF has undergone a thorough revamp, four years into its life, to help it face up to intense competition from the latest BMW 5-series and Audi A6.
The 2012 XF — which goes into production this July — has been given new front-end styling, tweaks to the rear, extra safety features and changes to the interior, including a new audio system.
Diesel XFs also get a new eight-speed automatic gearbox. But perhaps most important for the sales success of the XF is the arrival of a new four-cylinder diesel engine, which also gets a new stop-start system.
All versions of the new XF, including the XFR super-saloon, feature a new bonnet, wings, headlamps, grille and bumper, and modified rear lights. Adam Hatton, a Jaguar design manager, says the nose graphic of the XFR was intended to “turn up the visual volume and give a purposeful road presence”.
The most important technical aspect of the new XF is the new 2.2-litre AJ-i4D four-cylinder diesel engine, which is expected to account for around 60 per cent of future XF sales.
The i4D is adapted from the transversely mounted engine used in the Land Rover Freelander, but Jaguar says the unit has undergone significant changes and improvements in refinement.
With 188bhp and 332lb ft at just 2000rpm, the i4D unit has had changes to the block and sump, lower piston friction, a new camshaft, a water-cooled turbocharger and extra sound insulation. More sound deadening has been added around the bulkhead and behind the alternator, turbo and starter motor.
The upshot is a claimed 0-60mph time of 8.0sec, combined economy of 52.3mpg and CO2 emissions of 149g/km.
Sophisticated computational fluid dynamics calculations have been used to smooth the airflow under the car and around the door mirrors. The result, says Jaguar, is that the XF’s interior refinement is class-leading and as good as the current V6 diesel-engined XF.
Both the i4D and V6D engines are hooked up to a new eight-speed ZF auto ’box, which is fitted with a sophisticated stop-start system. Jaguar says the new transmission offers a much wider spread of ratios than the outgoing six-speed unit, as well as quicker shift times and the ability to engage on multiple downshifts, even from eighth to second.
The stop-start is triggered by the amount of pressure the driver uses on the brake pedal and is designed to restart the engine much more quickly than existing systems.
It uses a ‘tandem solenoid starter motor’ (which can spin itself up before engaging with the flywheel), a system to hold the fuel pressure in the fuel system and ‘hydraulic impulse storage’ in the gearbox, which ensures the oil pressure in the transmission is high enough for instant response in restarting.