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AD&P; > February 2014 > FEATURE > The Acura RLX Sport Hybrid: 6, 8 and 4 > Gary S. Vasilash > gsv@autofeldguide.com u In the front, there is a 35-kW motor that is integrated into a seven-speed dual clutch transmission (Acura's frst use of a dual clutch transmission with or without an integrated motor). In the back, there are two 27-kW motors and a 1.3-kWh lithium-ion battery pack. braking) to each wheel. And a clutch allows motor decoupling from the wheels. Asked about the big challenges that faced the team in developing this three-motor parallel hybrid setup, Aoki responds that it was making sure that they could coordinate the speed of the rear motors as required. It's one thing for the rear wheels to be at diferent speeds during cornering, but another entirely when simply propelling the car forward. The RLX Sport Hybrid can launch purely as an electric vehicle, using the rear motors. Then as there is more pedal depression, the engine takes over and the front motor acts as a generator to charge the li-ion battery u This is the Twin Motor Unit that's located in the rear of the car. It houses the back-to-back 27-kW motors, one to drive each of the rear wheels. 24 pack. Low-speed cruising is handled by the rear motors alone; the engine is not powering the wheels; high-speed cruising is accomplished via the engine. When there is hard acceleration from a stop, all three motors as well as the engine are brought into play; if it is a rolling hard acceleration the front motor isn't used to power the wheels. Engine power and rear motor power are used to provide AWD capability under slippery conditions. When the vehicle is decelerating, the front and rear motors supplement the hydraulic braking system; some brake energy is captured and put in the battery pack. (Speaking of the braking system: The car features an electric servo brake to provide a linear, stable braking feel during regenerative braking. And speaking of feel, there is a reactive force accelerator pedal with an electric mechanism in place of the typical spring mechanism that provides sensory feel through the pedal based on driving conditions (e.g., if the car is climbing a slippery hill, there is greater pedal resistance to encourage the driver to not get on the accelerator too much; if the forward collision warning system determines a crash is imminent, the pedal will push back even before there are visual and audible warnings.) Asked why they developed a threemotor hybrid system rather than a more-conventional two-motor system for the RLX Sport Hybrid, Hitoshi Aoki uses more than one word in his answer, although one word is certainly the most operative: "If we had one, it would be really, really boring."