SAN FRANCISCO -- Acura has taken its RLX sedan, strapped to a three-motor hybrid system that gooses horsepower to 377 from 310 with the added benefit of all-wheel drive, and transformed its vanilla full-sized luxury sedan into a stronger competitor.
The basics: Under the hood of the RLX Sport Hybrid is the same 3.5-liter direct-injection V-6 as the base RLX, but it gets a seven-speed, dual-clutch transmission mated to an electric motor. When combined with the two hybrid motors linked to the rear wheels, it creates "the most powerful Acura ever built."
The electric motors in Acura's hybrid system are designed to do more than boost power and save fuel. During cornering, the motors also power a torque-vectoring system that sends positive torque to the outside rear wheel and braking torque to the inside rear wheel. In theory, this creates an "optimal yaw moment," or more precise turn-in.
The hybrid motors allow the car to cruise in "EV mode" at up to 50 mph, with the gasoline engine off and transmission uncoupled. At cruising speed when the engine is running, cylinder deactivation maximizes fuel economy.
Many hybrids kill the engine when the car is at a full stop, but the engine's restart can often be abrupt and jarring. The RLX has active engine mounts and a changed camshaft profile to reduce that shock. Under braking, the rear motors provide regenerative power to the lithium ion battery.
The hybrid system is similar to what will be installed on the NSX supercar that comes in 2015.