After a rather protracted PR campaign, the Jaguar XE - Britain's BMW 3-Series fighter - showed its face in a slightly OTT ceremony a couple of weeks ago.

But that's not it for the XE promotion extravaganza: today we've learned more about the clever diesel engines that will account for the vast majority of XE sales. And which Jaguar surely intends to kick the BMW 320d firmly in its nether regions.

Called 'Ingenium', the engine range may sound like the name of one of the teams being castigated by Lord Sugar on The Apprentice, but JLR's new four-cylinder arsenal aims to wipe the floor when it comes to emissions.

A choice of two 2.0-litre four-cylinder turbodiesels will be offered, a 161bhp/380Nm version scoring the headline 3.8l/100km and 99g/km CO2 figures, and likely accounting for the majority of sales.

For comparison, a 320d with the parsimonious Efficient Dynamics tech combines identical performance figures (wonder what Jag's big benchmark was?) with 69mpg and 109g/km green numbers.

As with the Beemer, those more concerned with performance can opt for a more potently tuned diesel, which offers 178bhp and 430Nm. Jag is yet to reveal how much thirstier and more polluting this iteration is.

The current 2.2-litre diesel engines in the XF are rather too minicab-esque in the aural department, and the Ingenium range aims to fix that with an acoustic sump cover among the exceedingly nerdy tech contributing to 'exceptional quietness'.

If you still associate diesel engines with long-distance haulage, then fret not, as there will be abundant petrol options too, beginning with a pair of 2.0-litre turbocharged four-cylinders and a 3.0-litre supercharged V6.

And if our fastidious finger-crossing pays off, a production version of this entirely-made-up V8 XE R-S will follow.

The XE will be fighting for attention at the Paris motor show next week, when yet more tech info - including firm details on those petrol engines - will drop.