2012 Infiniti M35h / M Hybrid – Prototype Drive

As the first in-house hybrid from Nissan/Infiniti, the M35h is pretty unassuming. Indeed, although the test cars we drove in Japan were covered with decals advertising their gasoline-electricness, small “hybrid” badges on the production models’ front fenders will be the biggest powertrain giveaway once the cars arrive stateside next spring.

Now, before you frothily remind us that Nissan already has a hybrid in the Altima, remember that it uses technology licensed from Toyota, a complicated system with two electric motors and a planetary CVT. The M hybrid takes a simpler, Nissan-engineered approach to integrating electric power. Like the latest hybrids from Hyundai, Porsche, and Volkswagen, the Infiniti’s single electric motor is located between the engine and automatic transmission, in place of a conventional torque converter. The 67-hp motor is connected to the crankshaft via a wet-plate clutch. This allows the M to use its 1.3-kWh, 340-volt lithium-ion battery pack for electric-only propulsion at speeds up to about 60 mph as long as the driver keeps throttle application below 20 percent. During deceleration, the system will turn the engine off and decouple it from the driveline at speeds as high as 81 mph, as opposed to simply shutting off the fuel supply, which means some amount of energy is still being spent.

Should you need more power than the electric motor can supply, the gas-powered engine will kick in, although a second, dry clutch in front of the rear differential slips when the car changes from electric to gas mode to help smooth out any potential jolts. Nissan uses the designation VQ35HR for the 3.5-liter V-6 in the M35h. Technically, it’s the same engine that’s used in the EX35 (as well as in the M35 and G35 in previous model years), but in this application, the output is 302 hp and 258 lb-ft of torque. Infiniti is short on details as to all the ways in which this engine differs, but we do know that the M35h’s V-6 has different cam timing and uses the late-intake-valve-closing Atkinson cycle for greater efficiency.

There’s always a catch with hybrids, of course, and that catch is weight. In the M35h, the penalty is 265 pounds compared with a conventional M37, which Infiniti claims is 66 fewer pounds than the toll exacted by the Lexus GS450h’s hybrid system. That means the M35h should weigh in around 4300 pounds. The extra low-end torque provided by the hybrid system should offset the extra heft; we predict a 0-to-60-mph time of 5.5 seconds, the same as that turned in by the M37 in a recent comparison test. Of course, as in most hybrid sedans, the M35h’s battery pack sits behind the rear seats, compromising trunk space.

Our brief drive of a right-hand-drive, Infiniti-badged Nissan Fuga (as the M is known in Japan) suggests that the M37’s solid handling has been preserved, especially in the braking and steering departments. The only herky-jerky event we encountered was from mashing the accelerator pedal at low speeds. A jolting downshift from the seven-speed automatic transmission was followed by a second surge as the electric boost was routed to the rear wheels. We experienced the aggressive engine shut-off, too, as we observed the revs drop to zero while humming along at 70 mph. It’s easy to stay in electric mode, although we’ll have to wait until a stateside drive of the production car to see if the M35h keeps up in traffic without using the gasoline engine.

Infiniti claims the M35h has fuel economy close to that of a 1.8-liter economy car. If the M hybrid can match the numbers of an automatic-transmissioned Nissan Versa (which, conveniently, is available with a 1.8-liter engine), it would achieve EPA figures of 24 mpg in the city and 32 mpg on the highway. That would be an improvement of 6 mpg over the M37 in both categories, which seems reasonable considering the Infiniti’s bias toward performance and the lofty mileage numbers achieved by the Ford Fusion and Hyundai Sonata hybrids.

Oh, and there’s another catch with hybrids, and that is price. Again, Infiniti is short on details, but we expect the M35h to sit between the M37 and M56 in the product lineup. We’re also guessing the base price will be closer to that of the M56 than its V-6 counterpart, or about $53,000. Lexus has had a hard time moving many copies of the slightly more expensive (and performance focused) GS450h, and we aren’t going to predict significant sales for the M hybrid just yet. But we can already tell this Infiniti will be more fun to drive than the Lexus.