New, more efficient engine for Jaguar XF

The 2.2-litre diesel unit emits just 149g/km of CO2 emissions and is capable of delivering 52.3mpg, making it the best performing engine the Big Cat has ever made based on environmental credentials.

Despite this, the four-cylinder unit delivers 190PS and 332 lbs ft of torque. This translates into a 0-62mph sprint time of 8.5 seconds and a maximum top speed of 140mph.

Aside from the performance figures, the engine also differs from the current engine line up in Jaguar’s executive XF because it is essentially turned 90 degrees under the bonnet, in a north-south configuration.

This creates more space for a water-cooled turbocharged and other technology designed to make the new Stop-Start system more efficient.

Seen as an integral part of most new models, Stop-Start turns the engine off when the car is stationary for short periods of time e.g. in heavy traffic, and instantly switches it back on again when the brake is released.

Jaguar estimates the technology will improve efficiency by up to seven per cent in the XF when matched to the new engine.

Jaguar believes the engine will have benefits for the driver too, with increased sound deadening in place to reduce cabin noise.

As an executive saloon, low cabin noise and on-the-road refinement is an important factor for buyers, and Jaguar is aiming the new engine at the likes of BMW’s EfficientDynamics models.

The engine, which is currently being tested in an Jaguar XF test mule, will be used in a full production version of XF, most likely later this year.

Full details and specifications of the new engine option will be announced at the New York Auto Show next month.