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52 mpg Jaguar XF

Jaguar XF with new 2.2-litre diesel engine

Jaguar has developed a new 2.2-litre diesel engine that is capable of returning 52.3 mpg on the combined cycle along with emissions of 149 g/km of CO2.

The new 2,179 cc four-cylinder 16-valve common rail diesel engine develops 190 PS and 332 lbs ft of torque, and is installed in a north-south configuration for the first time.

January 2012 Update: We road test the Jaguar XF 2.2. Diesel Premium Luxury – and it scores an impressive 9/10

The new engine features a water-cooled turbocharger with low-friction pistons, new injectors and a new crankshaft. The new configuration allowed Jaguar engineers to add a new oil pan and new electronic systems affecting the crankshaft to allow the new intelligent Stop-Start system to operate more efficiently.

Intelligent Stop-Start aims to reduce the prolonged time spent in the shutdown and start-up phase usually experienced in such systems. The Jaguar system overcomes this partly through the inclusion of the new crankshaft sensor and fuel rail pressure holding system meaning the engine needs less time to restore drive through an innovative engine restart capability. This is best demonstrated when approaching a busy roundabout – in situations where the driver briefly brings the vehicle to a stop only to move off again quickly. In conventional systems the engine needs to shutdown completely before restarting again, leading to often frustrating delays. The Jaguar system is able to restart the engine while it’s shifting down from as little as 400 rpm meaning it does not need to come to a stop – drive is therefore restored more efficiently.

The inclusion of the Stop-Start function is estimated to increase overall fuel efficiency between five and seven per cent.

Along with a new engine, the development vehicle debuts an advanced eight-speed ZF automatic gearbox. With the seventh and eight ratios effectively acting as overdrive gears, the new gearbox allows the 2.2-litre engine to be optimised to deliver swift responses when required and effortless motorway cruising ability to ensure the ideal balance between efficiency and performance. The sprint to 62 mph takes 8.5 seconds before achieving a maximum speed of 140 mph.

The high levels of refinement expected of modern Jaguars are retained with engineers putting particular emphasis on sound deadening around the engine and bulkhead as well as active engine mounts to reduce vibration. The result is a 3dB reduction in cabin noise to make the car one of the most refined vehicles in its class.

The new powertrain is making its debut on UK roads fitted to a prototype development vehicle, and will feature in a future XF production car with specifications and an estimated on-sale date being announced at the New York Auto Show.