Hybrid cars may be high tech, but after hitting an apex in theand , the technology stagnated. But now a new generation of hybrid drive system is revitalizing the market. Using lithium ion batteries, these systems operate under electric mode over a greater range of speeds, delivering more efficiency. Such is the case with the 2012 Infiniti M35h, one of the first of the new generation of hybrid vehicle.
The M35h boasts EPA fuel economy of 27 mpg city and 32 mpg highway, an impressive achievement for a luxury sedan that also generates 360 horsepower. The car accelerates quickly, using both the 258 pound-feet of torque from the gas engine and the 199 pound-feet from the electric motor to press you back into the seat when the accelerator is mashed. And this same power train slips into EV mode for long stretches, even when traveling above 60 mph on the freeway.
Infiniti packaged this all-new hybrid power train in its top-of-the-line sedan, the M, a car that has never quite garnered the prestige of executive sedans such as the Mercedes-Benz S-class, the BMW 7-series, or the Lexus LS. The smaller M sedan isn't the kind of car for which you would hire a chauffeur. But it tries to compete with those other cars by offering similar levels of technology, and pushes driver assistance features to an extreme.
The M35h is one among a growing list of luxury hybrids.
Interestingly, the M35h is not alone as an executive-class hybrid. Last year, BMW released its, and Mercedes-Benz previously launched the . But of these cars, Infiniti really has the best hybrid system. It not only features idle stop, but it also is able to propel the car under electric power alone, and it gets the best mileage of its competition. It doesn't hurt that the M35h is the cheapest of the lot, either.
Gas and electric power
The M35h relies on Nissan's tried and true VQ-series engine, a 3.5-liter variable valve-timed V-6 as its gasoline-powered component. This engine, though landing on the Ward's 10 best engines list repeatedly over the years, is not very advanced by current standards, and was even knocked off Ward's 2011 list by Nissan's own electric motor powering the .
The trunk space is shallow because of the battery pack, but Infiniti says it still fits four golf bags.
However, the research Nissan did for the Leaf also paid off for the Infiniti M35h, as both cars use lithium ion battery packs. The M35h gets a 50-kilowatt pack mounted just behind the rear seats, compromising the trunk space. This battery powers a 67-horsepower electric motor capable of driving the car. A regenerative braking system, similar to that used in most hybrids, charges up the battery. Although this is a new-generation hybrid, there is no plug-in capability.
A gentle touch on the accelerator makes the car move forward in EV mode, indicated by a green light on the tachometer. With that same gentle push, the car will continue to accelerate under electric power, the engine remaining off. But so as not to cause a traffic jam and also to get the most out of the car, it works better to push off harder, spooling the engine up to cruising speed, after which it will shut down, only coming on as needed.
Switching the dial to Sport mode affects the throttle and transmission.
To maximize EV time, the car features an Eco mode, accessible with a dial on the console. Eco mode detunes throttle response to a sometimes frustrating degree. Forget about any sort of satisfying acceleration, the M35h will barely get out of its own way.
But the console dial has two other modes, Snow and Sport. Snow reduces torque to the wheels, and is meant to keep the car from losing traction on slippery roads. Sport mode generally keeps the engine speed above 3,000rpm, making for ready power. But even in Sport mode the car will switch to electric drive when conditions call for it.
Sport mode also affects the transmission, which explains why there is no separate sport setting on the shifter. With its seven gears, this automatic transmission helps the car's fuel economy mission. A manual mode lets the driver shift through the gears sequentially, and allows more aggressive driving than the Sport mode.
This animation shows the mix of power from the battery and engine.
Further putting the M35h in the efficient luxury camp more than sport luxury is the suspension, which is sprung soft. Infiniti also doesn't take the M35h's tech so far as to offer an active suspension. Sway bars keep the car reasonably stable under hard cornering, but as a fixed suspension, Infiniti had to find a compromise setting between rigid and soft.
Infiniti fits the M35h with an electrohydraulic power-steering unit, essential for times when the engine shuts down. At speed, it is difficult to tell that it is not a conventional hydraulic power-steering unit, attesting to Infiniti's tuning job. But it is also not exceedingly sharp, showing the kind of understeer present on average cars. Again, the M35h is more luxury than sport.
Almost drives itself
The climate control system in the M35h is also unaffected by engine shutdown, so it must rely on electric components. Climate control offers Infiniti's Forest Air feature, which causes air flow from the vents to fluctuate, the idea being to simulate a natural breeze. It is a subtle effect, and can be turned off with a button on the dashboard.