2012 Jaguar XF spy photos, new diesel engine at New York

The camouflaged images reveal the updated XF luxury sedan will adopt front-end styling similar to the larger XJ, trading the bulbous headlights for a sleeker design.

The rear will also enjoy a refresh, again with finer lines and a more shapely bumper.

The 2.2-litre diesel engine to be unveiled at the New York International Auto Show on April 20 promises to be the most efficient engine ever fitted to a Jaguar vehicle.

Producing 140kW of power and 450Nm of torque, the four-cylinder single-turbocharged engine utilises ‘Intelligent Stop-Start’ to return combined cycle fuel consumption of 5.4 litres/100km and emit 149g/km CO₂.

The smart stop-start system aims to reduce the time spent in shutdown and start-up phase. The engine will continue to run at extremely low engine speeds in specific conditions rather than shutting down and restarting altogether, which expends extra energy and leads to delays in power delivery.

Jaguar predicts the new Intelligent Stop-Start system will increase overall efficiency by five to seven percent.

The 2.2-litre diesel will be teamed with an eight-speed ZF automatic transmission for optimised efficiency and performance. Acceleration from 0-100km/h will take 8.5 seconds.

Particular emphasis was placed on improving NVH (noise, vibration, harshness) levels, and a 3dB reduction in cabin noise has been achieved thanks to sound deadening around the engine and bulkhead, and active engine mounts to reduce vibration.

More details of the new 2012 Jaguar XF and the new diesel engine will be revealed at New York next month.