Torque of the town

This combination eliminates the need for a torque converter and allows for the full decoupling of the V6 when there is adequate battery charge to drive the car using electricity alone. It also smooths things out during gear changes and when the V6 is being tuned in or out of proceedings.

The drivetrain architecture allows the M35h to run with either just the electric motor or the petrol engine, or a combination of the two. It also saves fuel by automatically switching off the engine when the car is stopped or stopping. In fact, as soon as you start to slow down the M35h usually drops into EV mode. Think stop/start but writ large.

The drivetrain

Being modular the IDRH system will eventually find itself in most if not all of Infiniti’s forthcoming models, including presumably the new premium compact that will go into production at Nissan’s Sunderland factory in 2015.

In the M35h, the electric motor serves a triple purpose: as a drive unit, a starter motor, and a generator to recover energy during deceleration and braking. On paper it’s one of the most compact and efficient hybrid system on the market and when it comes to energy recuperation it seems particularly efficient.

Even after deliberate attempts to drain the battery by maximising the EV-only range - the maximum electric-only range is quoted as 1.2 miles but I managed to get over two easily - the battery recovered to a full charge surprisingly quickly. Of course, part of the trick is the engine’s ability to charge the battery directly.

The compact size of the hybrid drive pays dividends when it comes to kerb weight. At 1830kg, the M35h is 95Kg lighter than a BMW ActivHybrid 5 and 80kg lighter than Lexus GS450h. That’s the equivalent of an extra passenger.

Energy flow 1: driving in EV mode

Once inside the M35h, you’ll search in vain for an ‘EV’ button. In fact, the only obvious e-car giveaways are the green EV light in the tachometer dial and the power/charge gauge.

But don’t assume this is hybrid-lite. You can travel under electric power at speeds up to 65mph, and in everyday motoring I was surprised to see how often the tacho needle would suddenly drop down to zero even when my foot was still on the throttle pedal.

Such is the refinement of the Infiniti that even with the stereo turned off it’s difficult to tell when the V6 has decided it’s not needed and metaphorically stepped outside for a fag.

On the emissions front, the Infinti screws the global pooch to the tune of 159g/km of CO2. By comparison, the Lexus GS450h returns 141g/km but the Lexus achieves this by using a CVT transmission, something that in my opinion has no place in a car with even vaguely sporting pretensions.

YEnergy flow 2: the V6 can charge the battery pack directly

The manufacturers’ economy figures as always err on the optimistic side. I covered over 350 miles in my week with the M35h and averaged 33.6mpg. That’s 16.8mpg less than the extra-urban best and 7.3mpg less than the on-paper average.

I should say in the car’s defence that most of the distance I covered was in a style best described as energetic and with the gearbox in Sport mode. You see, in addition to the manual gear selector, the M35h has four driving modes selected by a rotary knob on the centre console: Normal, ECO, Sport and, appositely given the recent weather, Snow.

Next page: Inside the Infiniti