From the outside, the 2012 Infiniti M35h hybrid looks just like any other model of the large luxury sport sedan. Only some subtle badges--one on each front fender, one on the trunk lid--denote its hybrid powertrain. It's the first hybrid for Infiniti, that gives the M35h the title of "fastest hybrid sedan" sold this year. Infiniti is proud of pointing out that it's the only car sold that has both 350 horsepower and a highway gas-mileage rating of more than 30 mpg.
The M35h pairs a 302-horsepower 3.5-liter V-6 with a 50-kilowatt (67-horsepower) electric motor sandwiched between the engine and a version of the company's seven-speed automatic transmission modified to maintain pressure even with the engine switched off. The maximum combined output of the entire powertrain is 360 hp. The motor can power the car alone, drawing energy from a 1.3-kilowatt-hour lithium-ion battery pack in the trunk, and it can contribute torque along with the engine to power the car. It also recharges the battery pack either through regenerative braking or using engine power. But unlike the dual-motor systems from Toyota and Ford, it can't both power and charge at the same time.
The EPA rates the 2012 Infiniti M35h at 27 mpg city, 32 mpg highway, for a combined rating of 29 mpg. That's impressive for a sedan this large and heavy that performs this fast. But keeping the fuel economy near those numbers may require using Eco mode, which not only reduces maximum power output but also stiffens the accelerator pedal to push back if the driver accelerates too aggressively. Drivers can override the feedback in emergency situations, but it's a clever and subtle way to encourage more fuel-efficient driving.
Knowing that U.S. drivers spend as much as half their time at speeds of 50 mph or more, Infiniti has tuned the system to deliver good fuel economy at highway speeds as well as in stop-and-go urban traffic. The M35h switches to electric-only mode quite a lot both around town and under light loads on the highway. Depending on your duty cycle, Infiniti says it can spend as much as 50 percent of the time in EV mode.
On the road, the hybrid system adds an extra burst of power when needed, both off the line and when passing at highway speeds. There's a slight delay as added power comes in from the motor, and the engine can sound rough at times, but there's a lot of acceleration on tap. Drivers can select from among four modes--Standard, Eco, Sport, and Snow--to change the personality of this large, luxurious sedan at the flick of a switch.
Another technology designed to maximize efficiency is Infiniti's electrohydraulic steering, which only switches on the electric motor that delivers power to the hydraulic-assist pump if the steering wheel is turned. The result is a steering system that offers good feedback to the driver through the wheel, while only using power when needed.
The 2012 Infiniti M lineup achieves a five-star crash rating, including the M35h hybrid model. And it's at the high end of the M range, with lots of standard luxury features on the base model, which has a sticker price of $47,400. That said, a technology package, a deluxe touring package, and a premium package can all quickly add $10,150 to the price for such safety features as forward collision warning and lane-departure correction.
For more details, see the full review of the 2012 Infiniti M35h on our sister site, TheCarConnection.