Overview Somewhat somnolent styling masks a very sophisticated powertrain
Pros Power, fuel economy, sophistication
Cons Weight, rear trunk storage capacity, complicated AcuraLink infotainment system
Value for money Excellent
What would I change? Less complication to the AcuraLink system and, in an ideal world, build the entire car out of aluminum to reduce the weight penalty of the electric drive system
How I would spec it? Just the way it is
Acura’s new RLX Sport Hybrid may be the best car you’ll never test drive. Never mind the reasons — the somnolent styling or the disastrous name change from Legend to RL — for the drop off in what was once the most popular luxury car in North America (the Legend accounted for almost half of Acura’s sales at its peak), the Sport Hybrid version of the RLX is one of the most supremely sophisticated luxury automobiles money can buy. Indeed, not only is the electrified version of Acura’s Super Handling All-Wheel-Drive system the technological equal of Porsche’s million-dollar 918, but it also will provide the underpinning — albeit with the gas engine moved rearward and the electric motors forward — for Acura’s own supercar, the much-anticipated NSX.
Unfortunately, if the recent sales history of the RL is any indication (Acura has sold, on average, less than 150 RL/RLXs annually since 2008), precious few of you will ever find yourself behind the wheel of this gem. More’s the pity.
2015 Acura RLX Sport Hybrid SH-AWD
Handout, Acura
So, what makes this 2015 top-of-the-line Acura so noteworthy? For one thing, it sports no less than four separate motivators, one of them gasoline — Acura’s ubiquitous 3.5-litre V6, this version with 310 horsepower — and three electric motors, one 47-hp version mounted directly to the engine/transmission unit and two more 36-hp units individually powering the two rear wheels.
More importantly, the finesse with which they power the RLX is nothing short of astounding. Depending on the mode, one can have the gas engine alone driving the front wheels or, if all hands are needed on deck, all four simultaneously coming together for one (fairly rapid) 377-horsepower charge. Under more moderate demands, only the two electric motors are used when leaving a stoplight, their low-end torque providing at least modest acceleration. On fairly level ground, the hybrid RLX can also glide at speeds up to 80 kilometres an hour on electric power alone. And in slippery conditions, the combination of the gas engine powering the front wheels and the electric motors powering the rears provides the all-wheel-drive traction needed.
Were this all the trickery the Sport Hybrid had to offer, however, it would be a waste of complexity — far less sophisticated hybrids perform much the same feats. The last little trick in the RLX’s repertoire, the part that has me salivating at the prospect of this technology fully NSX-ed out, is that Acura uses those two, individually controlled, rear electric motors to torque-vector power distribution.
2015 Acura RLX Sport Hybrid SH-AWD
David Booth, Driving
For the uninitiated, torque vectoring is the fancy-schmancy buzzword for transferring differing amounts of power to the rear wheels to get sporty cars to better turn in. Essentially, what happens is a microcomputer slows the inside rear wheel while simultaneously speeding up the outside rear wheel, both actions encouraging a more rapid pivot. In traditional all-wheel-drive systems — like Acura’s own Super Handling All-Wheel-Drive system — this is accomplished by simply braking the inside wheel while sending more power to the outside.
The infinite controllability of the RLX’s electric motors, however, allows Acura to slow the inside rear wheel by reversing the polarity of its motor while sending more electrons to its opposing twin. Keen minds, especially the environmentally conscious, will recognize the inside wheel’s reversal of polarity as the regenerative braking credited for the superior fuel economy of their electrified cars. This means that while cornering hard, the RLX is actually recharging its battery. Many modern cars claim to marry the seemingly disparate capabilities of performance and economy. Only one — the RLX Sport Hybrid — can profess to do both simultaneously.
2015 Acura RLX Sport Hybrid SH-AWD
David Booth, Driving
That’s all fine and good, but how does Super Hybridization work in real life? Well, Acura says it offers the performance of a V8 with the fuel economy of a four-cylinder. Half of that claim is absolutely true, Acura’s specification of 377 horses seeming to underestimate the RLX’s acceleration. On the other hand, positing that it sips fuel like a four seems like a fairy tale too far, my 9.3 L/100 km average about 20% higher than the 7.7 L/100 km the RLX is rated for. NRCan’s 7.5 L/100 km highway rating seems pretty spot on, but claiming one can get by on just 8.0 L/100 km of city driving seems a tad optimistic. Nonetheless, a 9.3 L/100 km average in a mid-sized luxury sedan weighing 1,980 kilograms is none too shabby. Besides, the Sport Hybrid is, like other hybrids, somewhat temperature sensitive. In warmer temperatures, it switches, more immediately, into its EV mode and will also travel farther on electric power alone both of which should bolster the consumption a little.
Is the RLX all that a hybrid can be? Not yet. Had Honda been more daring, it might have constructed its topflight sedan — a la Audi and Jaguar — of lighter-than-steel aluminum. The weight savings might then have allowed a bigger battery than the minuscule 1.3 kW-h lithium-ion affair, offering perhaps even more power and certainly longer EV operation. The battery also takes up a fair amount of space in the trunk, limiting cargo capacity.
That said, the integration of said battery, 3.5L gas engine and three electric motors is the most comprehensively choreographed ballet of electrons and hydrocarbons yet. That all this sophistication costs but $69,990 is message worth trumpeting. The RLX is deserving of more attention than it will get.
Handling, interior also impress in the RLX
2015 Acura RLX Sport Hybrid SH-AWD
David Booth, Driving
Lost in all this talk of sophisticated high-techery, I hardly mentioned the RLX’s more salient points such as handling and interior comfort. As for the former, the Sport Hybrid handles more adeptly than its somnolent exterior styling would indicate. It’s no BMW, but neither is it a Lexus LS460. Combined with an engine that makes distinct vroom noises, there is a surprising sportiness to the top-line Acura.
The interior is everything you’d expect of an Acura. It’s refined, luxurious and loaded with tech. My only complaint would be this last. The AcuraLink system is unnecessarily complicated and relatively difficult to manipulate. Ordinary tasks like pairing of phones or managing the split screen simply take too much effort compared with other systems. And with three different screens — the traditional gauges, the radio/air conditioning interface and the AcuraLink screen, there’s just too much going on. The leather seats and the push-button transmission, on the other hand, are to die for.
A breakdown of the Acura RLX Super Hybrid’s Drive Modes
2015 Acura RLX Sport Hybrid SH-AWD
David Booth, Driving
The RLX Sport Hybrid SH-AWD system is a model of complexity and ingenuity, its V6 gas engine, front electric motor and twin rear-mounted electric motors all working together in complete harmony. Depending on the situation, the Sport Hybrid can work in the following modes:
EV Launch: Under light-to-moderate loads, the rear motors alone provide driving power, relying strictly on the battery. In EV Launch mode, on a fully charged battery, the RLX may be able to travel as long as 10 kilometres.
Engine Drive: Under gentle acceleration after launch, the front wheels pick up the load using engine power only, while the front motor reverses polarity into a generator pumping electrons back into the 1.3-kilowatt-hour lithium-ion battery.
EV Cruising: When cruising at speeds lower than about 80 km/h, the rear motors can power the rear wheels using only battery power.
Power Acceleration: Under hard acceleration, at speeds up to 120 km/h, all four wheels are driven through a combination of the gas engine driving the front wheels and the rear electric motors powering the rear wheels. The front motor only provides assist under acceleration from a standing start and doesn’t contribute any motivation at highway speeds.
2015 Acura RLX Sport Hybrid SH-AWD
David Booth, Driving
Engine Cruising: When cruising at higher speeds, Acura has determined that the best fuel economy is achieved by having the gas engine alone power the front wheels. The front motor-generator, meanwhile, charges the battery whenever possible, using excess engine power.
Deceleration: When braking, both the front and rear motors reverse polarity and pump electricity back into battery pack. In this regeneration mode, the engine is disconnected to eliminate engine friction and maximize the recharging.
AWD: Under slippery conditions, all four wheels are driven using the gas engine to power the front wheels and the twin electric motors for the rear wheels.
Cornering under Deceleration: The inside rear electric motor reverses polarity, providing negative torque to the inside rear wheel. Positive (driving) torque continues to be applied to the outside rear wheel, offering faster turn-in. The reversing of the polarity of the inside rear motor also provides regenerative braking, recharging the battery
Cornering under Partial Throttle: Optimization of front-to-rear and right-to-left torque distribution for improved cornering performance.
Cornering under Acceleration: On corner entry, the same torque split is used as cornering under deceleration, i.e., negative (regenerative braking) torque on the inside rear wheel while more power is transmitted to the outside tire. At corner exit, however, this positive torque is sent to both rear wheels to provide maximum acceleration.
2015 Acura RLX Sport Hybrid SH-AWD
David Booth, Driving
The Specs
Type of vehicle Rear-wheel-drive, luxury four-door sedan
Engine 3.5L DOHC V6
Power 377 hp; 341 lb.-ft. of torque
Transmission Seven-speed dual clutch manumatic
Brakes Four-wheel disc with ABS
Tires 245/40R19
Price (base/as tested) $69,900/$69,900
Destination charge $1,995
Natural Resources Canada fuel economy (L/100 km) 8.0 city, 7.5 highway
Standard features Power door locks, windows and mirrors, tri-zone climate control air conditioning, Krell ultra-premium14-speaker audio system with CD/AM/FM/XM/MP3/WMA, Sirius satellite radio, Acura navigation system with voice recognition, AcuraLinks infotainment system, 11-volt power outlet, rear back-up camera, tilt and telescoping steering wheel, heated and cooled front seats, leather seats, 12-way power adjustable front seats, power moonroof, adaptive cruise control, auto headlights, dual front air bags, dual front side air bags, front and rear side curtain air bag, driver knee air bag, rear back up camera, tire pressure monitoring system, Blind Spot Information system, Lane Keeping Assist system, Stabilitrak vehicle control system, electronic brake force distribution
