Jaguar straight sixes to return

Jaguar looks set to return to its glory days of DOHC inline six-cylinder power.

That's one of the key take-outs from the technical briefings which accompanied the overnight unveiling of the British brand's all-new XE mid-size sedan.

Not that the six-cylinder XE S which starred at London's Earls Court early this morning featured the yet-to-be confirmed powerplant. That engine is a transplant of the supercharged 3.0-litre V6 from the F-TYPE and other existing Jaguar models.

Rather, the Ingenium range of four-cylinder engines that will power the rest of the XE line-up appears to be set to expand with inline six- (and three-) cylinder variants mooted.

The new Ingenium range of engines is based around a modular 500cc-per-cylinder structure with consistent bore centres and other shared architecture. Both petrol and diesel engines are included in the range, which will be built in a purpose-built greenfield $810m plant in the British Midlands.

Standout details of the designs include a rear-mounted cam drive, offset bores (to reduce friction) and the use of variable geometry turbochargers (at least on the diesel variants).

Details of the 2.0D low emission Ingenium turbo-diesel engine were announced at the XE's unveiling overnight. The 120kW/380Nm engine is expected to be joined by a higher output oiler and two petrol 2.0-litre engines at Paris motor show.

Jaguar will confirm more details on the wider Ingenium line-up at the October event.

But it's the return of an inline six to Jaguar that has caught the attention of most observers.

Ingenium engine range chief engineer, Paul Witworth, would not confirm the new inline six, but was adamant that the traditional Jaguar configuration held clear advantages over the V6s most manufacturers use.

“I'm not going to tell you whether we're going to do a V6 or an I6 [inline six]. But what I will say is an I6 has less moving parts for a start and when it comes to fuel economy and emission the less moving parts you've got the better you are,” Witworth told motoring.com.au.

“Straight-six cylinder gives some challenges for vehicle packaging — it's more difficult to [achieve good] crash [test results]. But the engine will be inherently more efficient. It'll be lighter and it'll be cheaper [to build],” he stated

“And when it comes to customer attributes everyone wants their performance, wants their drivability, wants their refinement, but they want their economy as well. So if you're trading friction inside an engine, an I6 becomes a nice option to have,” Witworth stated.

The suggestion of a return of a Jaguar six-cylinder echoes moves at Mercedes-Benz. The fact that the XE has been launched with a V6, however, tends to suggest that the timeline for the new engine's roll out is extended.

According to Witworth, Jaguar will roll out the full first-generation Ingenium line-up between now and mid-2017. The six is expected to appear in 2016 with the arrival of the all-new XF, itself based on the platform than underpins XE.

“Roughly every three to six months, we're [going to be] launching a new [Ingenium] engine throughout all of next year, all the year after and the half year after that. And then we're into the next iteration of development — because things don't stand still.”

The modular approach of the engine translates to a 4.0-litre V8 and temptingly, a 6.0-litre V12.

It's not clear whether the V8 and/or inline six will be offered in both atmo and forced induction versions. Nor is it clear whether Jaguar will continue to use supercharging in its larger capacity engines or move completely to turbo.

Witworth did, however, confirm that the company was seriously investigating hybridisation.

“We're looking at all hybrid options within JLR [Jaguar Land Rover]. And Ingenium will take them all — we'd be crazy to develop an engine family that wasn't hybrid-proof.

“Anything from mild hybrid to full plug-in [PHEV], Ingenium will support,” he stated.

Electrification aside, with the new XF expected to appear in 2016, we're tipping that will be the car that debuts the new Jaguar six.