The supercharged V8 gasoline engine has fuel economy gains of up to 11% with emissions reductions of more than 8%, while the naturally-aspirated V8 sees economy improvements of up to 8% with emissions down by more than 6%.

The engineering target in developing the 2013MY XF and XJ powertrain range was to optimise efficiency and enhance choice, while never compromising the effortless performance that is an inherent and vital characteristic in all our cars. Through intelligent use of forced induction, eight-speed transmissions and, where appropriate, Stop/Start technology, each derivative in the new XF and XJ ranges meets that enhanced efficiency goal while offering the performance thrill expected of a Jaguar.

—Ron Lee, Group Chief Engineer, Powertrains, Jaguar Cars

Eight-speed transmission. Following its introduction on the 2.2-liter i4 and 3.0-liter V6 Turbodiesel engines for 2012 XF saloons, the eight-speed ZF transmission is now extended across the entire XF and XJ ranges for the 2013MY offering better economy, reduced emissions and smoother acceleration compared to the previous six-speed equipped models.

For all installations the transmission’s operating software has been specifically tuned to ensure it perfectly matches the power delivery of the engines to which it is mated and offers the sporting feel, precision and smooth shifting.

With both a wider spread of ratios and more even spacing between them, the gearbox provides more seamless acceleration both from rest and when overtaking, while fuel consumption at high speeds is reduced. Gearshifts are executed in just 200 milliseconds while driver intervention is possible through the use of steering wheel-mounted paddles which allow multiple downshifts, allowing the desired gear to be selected almost instantaneously.

The use of lightweight, compact components including a rear differential with an aluminium casing means there is no weight or packaging penalty when compared with the outgoing six-speed models, while efficiency is improved through the use of an improved pump design and greater control of the gear elements.

Intelligent Stop/Start. Jaguar’s Intelligent Stop/Start system is able to shut down the engine in just 300 milliseconds after the car has come to a halt, allowing for fuel consumption improvements of around 5%.

Control algorithms govern when the Stop/Start should function according to a number of operational parameters including engine, ambient and cabin temperatures, whether the vehicle is fully at rest, vehicle power requirements and so on. A green ‘ECO’ symbol on the dashboard lights up when the engine is shut down by the system.

Having come to a halt and shut down the engine, the Intelligent Stop/Start system is able to restart smoothly in less time than it takes for the driver’s foot to release the brake pedal and depress the accelerator. It does so by utilizing a Twin Solenoid Starter (TSS) mechanism that features its own secondary battery to ensure that in-car systems requiring power are not affected. The unique advantage of the TSS system is that it is able to restart the engine even while it is still in its run-down phase, allowing for ‘change of mind’ functionality, for instance if the car is coming to a halt at a junction but then a gap in traffic appears.

2.0-liter i4 Turbocharged gasoline engine. With compact dimensions and low weight of 138 kg, the new all-aluminium four-cylinder 2.0 i4 Ti engine has a specific output of 120 PS/liter (118 hp, 88 kW per liter). It achieves this through a combination of technologies which results in peak power of 240 PS (237 hp, 177 kW) at 5500 rpm and 340 N·m (251 lb-ft) of torque available between 2000 and 4000 rpm.

The turbine housing for the low inertia turbocharger is integrated with the lightweight, thin-walled exhaust manifold, shortening the engine and catalyst warm up times and reducing emissions. Chain-driven variable timing of both exhaust and intake valves maximises the spread of torque and optimizes fuel consumption at part throttle while delivering maximum performance at high revs.

In the XF sports sedan this engine is capable of accelerating the car to 60 mph in 7.5 seconds and on to 150 mph (2241 km/h) while at the same time achieving 8.9 l/100km (26 mpg US) on the EU Combined cycle and CO₂ emissions of 207 g/km. In the all-aluminium XJ, this same engine accelerates the car to 60 mph in 7.0 seconds and on to a top speed of 150 mph while returning 9.3 l/100km (25 mpg US) and 216 g/km of CO₂.

3.0-liter V6 Supercharged gasoline engine. Jaguar’s latest supercharged gasoline engine, the 3.0 V6 S/C, features new combinations of technology allowing it to deliver 340 PS (335 hp, 250 kW) at 6500 rpm and 450 N·m (332 lb-ft) of torque between 3500 and 5000 rpm. Dual independent variable cam timing (DIVCT) and spray-guided direct injection (SGDI) is allied to new spark plug orientation that aligns the electrode for enhanced combustion efficiency. These features, combined with a compression ratio of 10.5:1, optimize power, torque and economy throughout the rev range.

The latest twin-vortex Roots-type supercharger is mounted in the ‘V’ of the engine and features electronically managed boost control which offers operating efficiencies of up to 20%. The engine features an system of counter-rotating front and rear balancer weights devised by Jaguar’s engineers in order to ensure its refinement matches that of the V8.

The 3.0 V6 S/C is capable of accelerating both the XF sports sedan and XJ limousine to 60 mph in 5.7 seconds and on to limited top speeds of 155 mph (249 km/h). Both cars also return identical fuel consumption figures of 9.4 l/100km (249 km/h) on the combined cycle and emit 224g/km of CO₂.

2.2-liter i4 Turbodiesel The 2.2 i4 Td launched in the 2012 model year XF is now available in two forms. The entry-level variant offers 163 PS (160 hp, 120 kW) and 400 N·m (295 lb-ft) of torque while the higher-powered version has been uprated from 190 PS to 200 PS (197 hp, 147 kW) with torque remaining at 450 N·m (332 lb-ft), with both versions also benefiting from engine management refinements. In the XF sedan this means emissions have been reduced to as low as 135 g/km CO₂, with combined fuel consumption now at 5.1 l/100km (46 mpg US).

Both 163PS and 200PS variants of the 2.2 i4 Td are also available in the new XF Sportbrake where, thanks to aerodynamics the match of the sedan, Jaguar’s most versatile model to date also offers the same emissions and combined fuel economy figures.