SEATTLE – With automakers needing to improve fuel economy and cut emissions due to pending CAFE regulations…probably…maybe…more light trucks are getting the hybrid treatment.

The Acura MDX Sport Hybrid, on sale this month in the U.S., is the latest in a small-but-growing string of luxury hybrid CUVs. Included in the group is the Lexus RX 450h, Infiniti QX60 and plug-in hybrid versions of BMW’s X5, Mercedes’ GLE and Volvo’s XC90 in the U.S. market. None are super sellers (the RX, with 8,561 deliveries, did best in 2016), but they all improve mileage over their non-hybrid counterparts, especially city fuel economy that can be dreadful in big CUVs.

Like the GLE and XC90, Acura’s effort leans more sport than hybrid, given the MDX’s brawny 321 total system horsepower but relatively weak 27 mpg (8.7 L/100) combined fuel-efficiency rating. For comparison, the RX 450h hits 308 total system hp but returns 30 mpg (7.8 L/100 km) combined. The GLE and XC90 have at least 400 hp total, but fuel economy in the mid and low 20-mpg (11.8-L/100 km) range.

In back-to-back drives with the RX here, the MDX is the more athletic and less obvious hybrid.

Thanks to Acura’s torque-vectoring all-wheel drive, made possible via its twin-motor unit in the rear, the MDX corners fast and flat, while the RX tips and tilts under hard acceleration in turns.

The transitions from gas to electric and back also are more obvious in the RX, as are transitions from mechanical to regenerative braking.

The MDX Sport Hybrid shares its platform with the non-hybrid MDX, which was redesigned in 2013 for ’14. Both bodies boast 59% high-strength-steel content, up from 25% in the second-gen MDX, and include a hot-stamped 1-piece door ring for improved structural rigidity in the event of a collision.

To bolster the MDX hybrid’s floor and protect the hybrid componentry, including the 1.3-kWh lithium-ion battery pack, Acura engineers added three cross members in the center of the chassis. The beefed-up structure also serves to boost ride comfort and lessen noise, vibration and harshness, Acura says.

All MDX exterior dimensions remain the same for the hybrid, as do all interior dimensions including cargo space. Because Acura planned the hybrid variant from the start of the current-gen MDX’s development, all hybrid components, including the Li-ion pack, fit neatly under the vehicle’s floor.

The CUV uses Acura’s 3-motor hybrid system first launched in the RLX Hybrid sedan and now in the NSX supercar. The three motors, a larger one in front integrated into a 7-speed DCT and two smaller motors in the rear, pair up to a 257-hp 3.0L SOHC port-injected V-6. The front motor provides supplemental power and torque to the engine as well as converts engine power into electricity for the battery, while the rear motors provide AWD capability, able to shift up to 100% of torque between back wheels. They also provide regenerative braking power to the battery.

Because of reserve power available in the batteries, torque vectoring between rear wheels is available anytime in the MDX hybrid, even when a driver is off the throttle. Reaction time of 90 milliseconds is more than twice as fast as with a purely mechanical torque-vectoring system, Acura says.

The CUV’s propulsion system operates covertly. Watching the behind-the-sheet-metal machinations via a power-flow graphic on the center-stack screen is in our experience here the only way to know what’s going on. The DCT is especially clandestine in its operation, a nice change from the shift-busy 9-speed automatic Acura uses in some models.

The MDX hybrid’s power-control unit marks the first time Honda has installed a (waterproof, breathable) PCU on the outside of the vehicle. The packaging of the PCU, the Li-ion battery pack (dubbed the “intelligent power unit”) and twin-motor unit is 39% more efficient than in the RLX hybrid, Acura says.

Yaw and dampening are improved with the placement of those components middle-low in the vehicle, and drop the MDX’s center of gravity by 1 in. (26 mm).

Like many new luxury models, the MDX hybrid has a variety of driver-selectable modes that adjust steering, dampers, the degree of active sound canceling and throttle response, as well as the amount of electric assist. Of the four modes, comfort, normal, sport and sport+, the latter is the only one that allows the engine to run constantly for a vigorous, go-go character. It also is the only mode truly obvious from behind the wheel with clearly more aggressive throttle tip-in and firmer steering.

The MDX hybrid uses active dampers with more rebound performance and more compression than those in the non-hybrid MDX for better handling and ride comfort. The same algorithm from the NSX is used in the MDX to control dampers, Acura says.

For fuel-economy purposes, we spend most of our time in comfort mode. However, it is during our afternoon leg, when we use sport and sport+ modes more often while zipping back into town on an open freeway, that we return a day’s-best 28.3 mpg (8.3 L/100 km). The morning leg, with stop-and-go freeway traffic and 2-lane country roads, gets us just 23.6 mpg (10.0 L/100 km).

The MDX Sport Hybrid’s interior design and materials compare nicely to the RX and QX in that it has plentiful soft-touch materials, contrast stitching and wood trim. The MDX stands out with its matte-finish open-pore wood vs. the heavily glossed trim in the Lexus and Infiniti CUVs. Both trim types are attractive, but the open-pore wood reads more modern.

The MDX’s seats are comfortable and supportive in the first and second rows. Its third row remains a space best-suited to very flexible adults and/or small children. Climbing in and out is a chore, and legroom and headroom are tight.

The updates bestowed upon the non-hybrid MDX last year flow into the hybrid model, including second-row captain’s chairs in the upper grade with a generously sized center console in between. That feature plus a front console with a large storage box gives the CUV ample space for stuff.

The worst part of the MDX is its HMI. The CUV’s two small center-stack screens still are a head-scratching puzzle as we try to figure out what info is supposed to appear where. They also present dated graphics and have little flexibility in information presentation.

In this tech-obsessed age, interior screen size seems to be the new version of horsepower wars. The European luxury brands and Lexus trounce Acura and Infiniti on this mark. The RX’s optional 12.3-in. (31-cm)-wide display screen tested here has crisp and clear graphics and fonts.

Acura last year presented an interior concept with much-improved displays, but their integration in production models still is a few years out.

While the MDX’s navigation maps are dated, the turn-by-turn arrows look modern and come in handy when driving in an unfamiliar city.

Voice recognition, part of the upper grade’s advance package, takes a full 30 seconds to tune to a different SiriusXM channel. Ugh.

As with most Honda-built vehicles, there are few fit-and-finish foibles. Door-pocket flashing and exposed grab-bar pins are the most obvious flaws.

For those who care about such things, cupholders are of excellent quality, with sturdy plastic retractable nubs, and the circular-knit headliner is wrapped, not cut, at the windshield.

While its combined fuel economy isn’t as high as you may expect for a hybrid, it’s pricing is lower, making the MDX Sport Hybrid an intriguing business case for Acura.

The CUV starts at $51,960 for its base grade, which includes Acura’s technology package (navigation, premium audio, blindspot detection) as standard equipment. An AWD non-hybrid MDX with the tech package is $46,050; an RX 450h will set you back at least $53,000, and the European plug-in models at least $62,000.

Given the Euro group’s pricing, the MDX Sport Hybrid with Acura’s advance package (perforated Milano leather with contrast stitching, second-row captain’s chairs) still is a good deal. Between the two grades, Acura easily should be able to meet its goal of selling 5% of all MDXs with a hybrid powertrain.

cschweinsberg@wardsauto.com