Detroit Motor Show - This is the Infiniti Q Inspiration concept, to our eyes the prettiest shape of the new year so far but, as gorgeous as it is, and as strikingly minimalist as the interior tries to be, it's the VC-Turbo engine, which recently went into production in the QX-50, that's still getting me really revved up.
When I was at engineering college in the 1970s a fellow student came up with the idea of variable cam timing and duration as a way to increase the efficiency of an internal combustion engine. The advantages were obvious - but we couldn’t figure out how to do it. Today, of course, variable valve technology is commonplace.
As the owner of a motorcycle with a compression ratio so high that it required petrol of at least 100 octane to avoid engine damage, I would have preferred to be able to adjust the compression ratio to suit whatever fuel was available, but never said anything because I really thought it was impossible on an overhead camshaft engine, although the Waukesha Motor Company got it right on a pushrod single in 1928; the principle is still used to measure the octane rating of petrol samples.
But now, 40 years later, Infiniti has done it; the VC-Turbo engine - first seen in the Infiniti QX-50 - is a straightforward two-litre DOHC turbopetrol four, but instead of conventional con-rods it has a multi-link system that seamlessly varies the distance between the crank and the gudgeon pin, adjusting the engine’s compression ratio to suit the needs of the moment.
Note that the stroke of the piston remains the same and the capacity of the engine doesn’t vary, but because the piston is closer to the cylinder head at its highest point, compression is increased.
The VC-Turbo engine varies its compression between 8:1 (for maximum power and torque at the expense of high fuel consumption) and 14:1 (for optimum efficiency at lean fuel mixtures and the lowest possible fuel consumption) while the single-scroll turbo is mounted directly to the cylinder head for immediate response at any speed or compression ratio.
Although the system is complicated and expensive, it can provide the power output of a conventional 3.5-litre V6 at the fuel-consumption level of a two-litre turbodiesel four, and Infiniti sees it as a low-emission alternative for markets where infrastructure for widespread electrification is lacking.
In the Q Inspiration concept, the VC-Turbo powers an intelligent all-wheel drive-train that defaults to efficient front-wheel drive, but can send torque to individual rear wheels as needed.
Because the VC-Turbo is a lot more compact than an equivalent V6, the cabin of the concept has been extended, moving the A pillars further forward than in most medium-sized sedans, and making possible a dramatically sweeping roofline that meets a rising waistline at the trailing edge of the body, accentuated by a narrow, full width tail-light across the rear of the car.
The bonnet is short, over a tall, deeply chiselled air intake that Infiniti says previews future production, while the glassed boolid is long, opening like a crocodile’s mouth for convenient access to the cargo bay. Rear-hinged back doors obviate the need for B pillars, and the extended floorline gives the concept interior volume more akin to larger luxury sedans, with individual luxury seating for four.
Each seat has a floating touchscreen, positioned to allow you to cross your legs in comfort, while thin-frame ‘zero gravity’ seats, a low-mounted rear driveshaft and a floating centre console maximise leg room.
Driver and passengers can call up a ‘meditation-regeneration’ mode that minimises the level of information displayed, and offers guided meditation to help you leave your stresses stress behind when you start a journey. The car can also monitor passenger biometrics.
The dashboard is trimmed in kabazakura wood, a member of the birch family, with an traditional Japanese finish that leaves the grain still detectable to the touch, while the soft surfaces are finished in dot-quilted white leather with coral orange highlights. The floor and the area between the dashboard and the base of the windshield are trimmed with black leather.
Infiniti insists that its ProPilot autonomous driving support plan is committed to keeping the driver in control, while using cameras and radar to plot the road ahead, and monitor surrounding traffic, so you can delegate mundane, boring tasks such as freeway driving, intersection auto-navigation and stop-go city traffic.