 A previous-gen Honda Accord fitted with Precision All-Wheel Steer, which we'll see in the 2014 Acura RLX We have a pretty good idea what the new Acura RLX looks like based on the concept shown at this year's New York auto show. And now we've test-driven both versions of the RLX's powertrain at Honda's Tochigi, Japan, proving grounds. Our test cars were previous-generation Accords equipped with RLX running gear. The front-wheel-drive version debuts first next spring. It's powered by a direct-injection version of Honda's 3.5-liter V-6 making at least 310 hp and 265 lb-ft of torque, which is basically the same output as the 3.7-liter in the outgoing RL sedan with a claimed 10 percent increase in fuel economy. A six-speed auto manages the gear swaps. Key to the front-wheel-drive RLX is what Acura calls Precision All-Wheel Steer (yes, animal lovers, it spells PAWS). This system has two electric motors built into the rear toe link, and each link can act independently, a world first. Under braking, PAWS will increase toe-in for enhanced stability. In a lane-change maneuver, the rear wheels will steer in the same direction as the front wheels, whereas the rear wheels turn opposite of the front in tighter corners. The total adjustment is roughly two degrees in each direction, and a Honda engineer on hand said it acts in less than a second. It also works at all speeds. On our test drive, a few laps around a 0.8-mile handling course, the RLX exhibited much less understeer than we expected from a large front-wheel-drive sedan. Turn-in was especially sharp, and the car held the line particularly well in sweeping corners. When coming out of corners, we did notice a slight bobble as PAWS adjusted, not enough to upset the chassis but enough to tell that the system was working.  A Honda Accord fitted with Sport Hybrid SH-AWD, as will be seen on the 2014 Acura RLX The all-wheel-drive RLX forgoes the rear-wheel steering and instead employs what Acura calls Sport Hybrid Super Handling All-Wheel Drive. This new version of SH-AWD uses two 27-hp electric motors at the rear wheels instead of a driveshaft and clutch packs. The 3.5-liter V-6 still is present under the hood, but paired to a seven-speed dual-clutch automatic with an integrated 40-hp motor that also acts as a generator. Peak total system power is about 370 hp, but the car feels stronger thanks to the instantaneous torque of the electric motors, which assist propulsion up to 75 mph. The rear motors also provide torque vectoring in corners, putting resistance on the inside wheel (which generates electricity for instantaneous use, lessening the draw on the 6.7-kWh battery) and driving the outside wheel to minimize understeer. Track performance is impressive, with instantaneous turn-in and grip that seems to transcend the abilities of the Michelin Pilot Sport 3 tires. We didn't have the chance to mess around too much, but there is no power oversteer. Jam on the gas and the car simply follows exactly where you point it with a neutral attitude.
There are other benefits to the system, as well. Not counting the batteries, the rear motors weigh less than the driveshaft and clutches in the mechanical SH-AWD system. Those motors, which can provide silent EV-style propulsion at low speeds have the side benefit of smoothing out the engagement of the dual-clutch transmission when pulling away from a stop. And the hybrid system helps fuel economy—we estimate EPA figures of around 30 in both city and highway driving, a big jump from the current RL's 17/24 sticker. Our brief preview has us eager to drive the full-production RLX, even if we're not too excited to spend any time gazing at the, um, polarizing design. While the front-wheel-drive version offers interesting new technology with the all-wheel steering, we're enthusiastic about the Sport Hybrid SH-AWD, a far more revolutionary concept in terms of performance. Stay tuned. Read full story »from Car and Driver Blog http://blog.caranddriver.com | |||
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Monday, November 12, 2012
Sampling the 2014 Acura RLX’s Goodies: Precision All-Wheel Steer and Sport Hybrid SH-AWD
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