Infiniti QX50 Concept mid-size SUV revealed ahead of Detroit

Infinity will unveil the missing link in its SUV range at Detroit's motor show next week, complete with future-proof autonomous technology and the industry's first variable-compression engine.

The QX50 will be shown in concept form, a step up from the QX Sport Inspiration that was displayed at the Beijing and Paris motor shows in 2016 to gauge pubic opinion.

The new SUV, slated for production later this year in the US, fills in the range that now starts with the baby QX30 and expands through the QX70 to the Patrol-based QX80.

It also becomes the second generation of QX50 in the US after its predecessor, the EX37, though will share no dimensions or components.

The Detroit QX50 Concept highlights the manufacturer's moves into autonomous operation and will spearhead Infiniti's moves in this direction. However the company has pulled back from classing the SUV as having fully-autonomous capabilities.

Infiniti said it its ProPilot system would have "autonomous drive support" technologies designed to work with the driver and capable of being turned on and off at the driver's direction.

In a statement, Infiniti said ProPilot would act as a "co-pilot" and assist in functions including navigating in low-speed traffic conditions by following the vehicle ahead.

Infiniti will display its innovative variable-compression ratio engine at Detroit, loosely implying that this engine could make its first production appearance in the QX50.

It is not known when the production QX50 could be made available in Australia.

Announced in August, Infiniti claims to have found the "holy grail" of engine development by developing one capable of automatically changing its combustion process to switch between high fuel efficiency and high performance, replicating the benefits of a diesel and a petrol engine respectively.

It is able to adjust the compression ratio to suit driver demand and driving conditions, varying it between 8:1 for high-performance driving and up to 14:1 for more economical cruising.

Infiniti said the VC-Turbo 2.0-litre turbocharged petrol engine, which is claimed to produce up to 200kW and yet is 27 per cent more fuel efficient than a V6 engine of comparable power, is production ready.

The QX50 Concept shows few body changes compared with the QX Sport Inspiration version shown at the 2016 Beijing show and updated at the Paris motor show.

Externally, its headlights, grille and profile are virtually unchanged from its concept show cars.

Infiniti global president Roland Krueger said in a statement that the QX50 Concept would help give the brand a presence in the lucrative mid-size SUV segment.

"With the unveiling of the QX Sport Inspiration at the 2016 Beijing Auto Show, we showed the future of Infiniti QX models," he said.

"The new QX50 Concept evolves this concept further and shows how Infiniti could develop its future presence in the fastest-growing vehicle segment globally."

It is not known when the production QX50 could be made available in Australia.

When it does, possible engine configurations could debut the new VC-Turbo unit and those current on duty in the Infiniti range, including the 125kW/400Nm 2.2-litre turbo-diesel four-cylinder, a 235kW/360Nm 3.7-litre V6 and a 175kW/550Nm 3.0-litre diesel six.

Is variable compression technology the next big thing for engine development? Tell us what you think in the comments below.