Acura's Future Car Preview Drive

We Sample Three Potential Future Acura Drivetrains

Nobody in Honda's corporate management is satisfied with the Acura brand's current lineup, but fixes are on the way, coming sooner rather than later, that will bolster the brand's performance/fun factor and its green/tech cred. Starting at the top of the line, let's all stop pining for a V-8 right now, as it appears unlikely. Instead, Acura proposes an electrified riff on its venerable Super-Handling AWD that combines a 310-hp, 265-lb-ft direct-injected 3.5-liter V-6 with a 40-hp, 96-lb-ft electric motor and a seven-speed dual-clutch transmission at the front, abetted by a pair of 27-hp, 52-lb-ft electric motors driving the rear wheels. All output figures are estimated minimum levels and peak combined output figures weren't provided, but when you add them all up by mashing the go-pedal, the system delivers V-8 performance with (claimed) four-cylinder fuel consumption. At the other end of the spectrum are a pair of direct-injected engines -- a 2.4-liter gasoline four and a 1.6-liter turbodiesel.

 

We recently got a chance to sample each at Honda's Twin-Ring Motegi motorsports park northeast of Tokyo. The next-gen SH-AWD system features several novel elements. For one, the electric motor in front is not bolted directly to the engine, but rather to the opposite end of one of the gear shafts in the Honda-designed dual-wet-clutch transmission. This allows the electric motor to start the engine in auto start/stop mode while permitting the engine to be decoupled for electric-only propulsion. It also allows the electric motor much more authority to capture regenerative braking energy than is possible in other Honda IMA hybrid arrangements that lock the engine crankshaft and electric motor.

Relative to today's mechanical SH-AWD, which relies upon planetary gears to multiply torque to one rear wheel or the other when accelerative force is being applied, the rear-mounted electric motors can accelerate or slow either wheel independent of throttle position, so they can apply torque-vectoring under steady-state cruising and deceleration as well as acceleration. Engineers claim it can also apply power regenerated from an inside wheel to accelerate the outside wheel, though we suspect those electrons get routed through the battery. We only got one brief lap, but it was enough to suggest the V-8-performance claims have merit and that the electrified rear axle does indeed enhance handling over a much wider set of driving circumstances. It also feels really green to be able to arrive at and depart a stoplight (or a Hollywood red carpet) silently in EV mode. The rear motors handle this initial launch, and can coax the prototype Accord we were driving up to 24 mph if you're gentle with the throttle. It reverts to electric mode below 18 mph.

We also sampled a direct-injected version of the 2.4-liter engine in what we know as the TSX. Output figures weren't provided, but the torque diagram indicates a 10-percent boost in peak torque and a fatter torque curve, tapering down to an equivalent number at 7000 rpm (the current TSX's power peak), so let's guess power remains unchanged at 201 hp and torque climbs to 189. Acceleration felt noticeably lustier than the TSX I had driven just two weeks prior, and the engine note sounded somewhat more playful at full boil as well.

The tiny 1.6-liter TDI mill was the most impressive one, however. A new aluminum alloy used in the block permits an ultra-light open-deck design that helps this engine rank as the lightest of its size in the world, undercutting the weight of some gasoline engines. Output is rated at 118 hp and an incredibly strong 221 lb-ft of torque, and Honda claims it achieves best-in-class output and efficiency in the 1.6-liter class. Nobody who strapped in and blasted off in this TSX would believe the engine was under two liters. Redline is 4500 rpm, and in a car this size the gearing is short-ish, so you must row the manual six-speed a bit, but if this performance were married with real-world fuel economy of 40-plus mpg, it would likely prove as popular the VW Jetta's TDI option. Engineers say it would require a urea exhaust aftertreatment in a TSX-sized car, but probably not in a Civic weight-class vehicle like the forthcoming Civic-based Acura, so we're guessing that may be where it ends up.

Now if Acura can clean up its styling a bit -- and we expect big things from next month's supercar unveiling -- things should be looking up nicely for the caliper brand.