Thursday, 25 September 2014

Jaguar's XE diesel: its most efficient yet

Jaguar claims the USP of its new Ingenium diesel engine makes the rear-wheel drive XE the most fuel-efficient Jaguar yet, with CO2 emissions from just 99g/km.

The Ingenium range is produced at the new £500 million, 100,000 square metres UK Engine Manufacturing Centre in the West Midlands.

Jaguar also claims the plant will allow will come off the fully flexible lines at rates of up to one every 36s.

With a clean sheet approach, Jaguar’s powertrain engineers claim their aim was to make the Ingenium engines as light and efficient as possible, and deliver the blend of power, torque and smoothness customers expect. These state-of-the-art engines were proven over 2 million miles of real-world testing.

“The new generation of Ingenium diesel engines are wholly designed and manufactured in-house. No opportunity has been missed in ensuring their design is right on the cutting edge of technical advancement,” notes Ron Lee, Jaguar’s group chief powertrain engineer.

Engineers claim the low-friction, all-aluminium units have stiff cylinder blocks. Interestingly, there are twin-balancer shafts for low levels of vibration.

Twin-balancer shafts are expensive items to smother unwanted vibrations but nonetheless are necessary to achieve the levels of NVH sought for this class of vehicle, especially when higher powers and torques are required from the engine

Certainly, further down the road and to meet competition head on, the company will want to offer diesel engines with well over 100bhp/litre, possibly using variable geometry twin turbochargers.

For example, the Euro 6, SCR 2-litre TDI BiTurbo engine in the Volkswagen Passat develops 240PS (237bhp. 177kW) and 500Nm (396lbft) of torque. The block is designed to cope with 200bar firing pressure and a piezo fuelling system running at 2,500bar. For this vehicle, VW claims to have cut weight by 85kg based on the MQB structure. It claims to have shed 40kg (88lb) in the engine alone. How did it do that?

For such powers and torques, and when Jaguar wants to increase swept volume (for example, by increasing the bore), twin-balancer shafts could come into their own. However, there is the issue of how much the added complexity of twin-balancer shafts, which run at twice crankshaft speed, cost the engine in terms of power consumption; and the true cost-benefit. Jaguar’s engineers will be aware of all these figures.

Among OEMs which have used the device since Dr. Frederick Lanchester first came up with the idea include most notably Mitsubishi Motors; others include Alfa Romeo, Nissan, Porsche, Toyota and Volkswagen.


Other details include an acoustic sump cover, decoupled injectors, and an 0.5mm ovality on the injection pump drive sprocket, all of which are reputed to contribute to the Ingenium’s quietness. The ovality must have been introduced to quell some particular issue affecting NVH.

According to Jaguar, the new XE will feature two versions of the 2-litre Ingenium diesel. The first, rated at an output of 163PS and 380Nm torque, delivers benchmark efficiency figures of 75mile/gal and 99g/km CO2 “without any compromise” to launch performance or mid-range acceleration.

The 180PS/430Nm variant has “one of the highest torque outputs” in the class.

According to Jaguar, Ingenium diesels meet Euro 6 and are “as clean as they are efficient”. Variable exhaust valve timing shortens the catalyst light-off phase and also improves diesel particulate filter (DPF) regeneration. The cooled low-pressure exhaust gas recirculation (EGR) system reduces combustion chamber temperatures, inhibiting NOx formation. Selective catalytic reduction (SCR) technology cuts NOx emissions to low levels and the new XE has been engineered to meet the most stringent global regulations.

Jaguar notes that Ingenium diesels will be joined at launch by “powerful, efficient”, direct-injection gasoline engines in four-cylinder 2-litre turbocharged form as well as the well-known supercharged 3-litre V6.

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