Jaguar boosts power/torque of XJ diesels

Eight out of 13 of the models of the revamped Jaguar XJ luxury saloon are powered by a more powerful 3-litre diesel engine.

The XJ – which dates to 1968 – is still regarded as Jaguar’s luxury car. In 2003 the car’s technology more forward radically with the introduction of the company’s “road map” and the introduction of its first all-aluminium body-in-white – the precursor of the latest thinking in Jaguar’s lighter-weight cars and their use of Henrob self-piercing rivets (SPRs).

Subtle changes have been made to the exterior design, accentuated by full LED headlights. Materials such as semi-aniline leather and inlay veneers enhance an interior already considered the most luxurious in the segment, culminating in the new Autobiography model.

Matching this traditional craftsmanship is state-of-the-art technology, including a new infotainment system. InControl Touch Pro offers features such as door-to-door navigation and 1,300W Meridian digital audio system.

The driving experience is improved as the Ford V6 diesel engine offers more power and torque and reduced fuel consumption and CO₂ emissions. The electric power-assisted steering system enhances Jaguar's reputation for unrivalled agility and responsiveness.

The 3-litre V6 diesel, with its compacted graphite iron (CGI) cylinder block has been enhanced to include new technologies designed to boost output and reduce emissions.

Now Euro 6 compliant, the engine develops 700Nm and can accelerate the XJ from 0-60 mile/h in just 5.9 seconds, yet returns 149g/km CO₂ on the European combined cycle.

The latest-generation V6 diesel has seen its power increase from 275PS to300PS – 100PS/litre. And torque has risen from 600NM to 700Nm. Earlier this year, JaguarLandRover announced the 2016 Range Rover Diesel and the Range Rover Sport Diesel powered by the 3-litre V6 diesel engine. However, the power and torque levels of 254bhp and 440lbft (596Nm) torque are below those of the power units for the latest XJ. This further serves to highlight the importance that Jaguar attaches to its XJ range as a premium product.

Jaguar claims the engine is “smoother and quieter than ever”, with the extra torque not only improving responsiveness but greater efficiency, helping to reduce emissions from 159g/km to 149g/km CO₂.

Jaguar also claims the 3-litre diesel gains from “even more sophisticated common rail and turbocharging systems” to boost power and torque. Ford makes the 3-litre V6 diesel at its Dagenham Engine Plant, UK.

The company claims new eight-hole piezo injectors ensure fuel is delivered with even greater precision and control, while increasing the maximum injection pressure to 2,000bar ensures even better mixture formation.

The innovative parallel-sequential boosting system receives more aerodynamically-efficient turbochargers, while the primary turbo now features “highly-advanced” ceramic ball bearing technology: the reduced friction means even better launch performance and transient response because torque builds up even more rapidly than before.

Although Jaguar does not name the turbo supplier, Honeywell claims it is the leader in this field.

Ceramic ball bearing technology originated in aerospace and has spread into motorsports and is now moving mainstream – commercially launched in both passenger car and commercial vehicle segments. Ceramic balls are lighter than steel balls and aid responsiveness.

Honeywell says it is “a pioneer in ball bearing technology and has solidified its leadership in the area through successful commercial launches in high-profile vehicles.”

In 2010, Honeywell ball bearing technology was adopted by Daimler AG for its 3-litre V6 diesel engine equipped on Mercedes-Benz E, C, S and R class series.

Turbonetics Inc of the US also makes ceramic ball bearing technology turbochargers.

Meanwhile, Jaguar’s 3-litre diesel also has a switchable coolant pump and dual-stage oil pump to ensure faster warm-up and reduced parasitic losses.

And, because the engine is now Euro 6 compliant, the exhaust gas recirculation (EGR) system now features a cooled low-pressure circuit in addition to the high-pressure circuit: this enables lower emissions of oxides of nitrogen (NOx) as well as reduced pumping losses across a wider range of the engine's operating map.

Complementing the improved EGR system is a selective catalytic reduction (SCR) system. Injecting a urea solution upstream of an SCR catalyst converts NOx into nitrogen and water to ensure the new XJ meets Euro 6 exhaust emissions regulations.

Meanwhile, in Dusseldorf, Germany this week at the GIFA world foundry trade fair, SinterCast demonstrated that an assembled 3-litre (Audi) V6 diesel engine with a CGI cylinder block is 125mm shorter and 15kg lighter than a (Mercedes-Benz) 3-litre V6 diesel engine with an aluminium cylinder block.