A record seven of this year’s Ward’s 10 Best Engines winners integrate state-of-the-art direct fuel injection, demonstrating the rapid pace of technology development as auto makers downsize their engines in anticipation of strict U.S. fuel-economy rules.

Direct injection gained popularity more than a decade ago with the arrival of modern clean turbodiesel engines, especially in Europe, and now high-pressure gasoline direct injection is sweeping across the industry in everything from entry-level compacts to luxury cars and fullsize pickups.

Direct injection, whether deployed in diesel or gasoline engines, has been proven to reduce fuel consumption and improve low-end torque, which makes for quicker acceleration.

This year’s winners and the applications tested:

  • 3.0L TFSI Supercharged DOHC V-6 (Audi A6)
  • 2.0L N20 Turbocharged DOHC I-4 (BMW Z4/528i)
  • 3.0L N55 Turbocharged DOHC I-6 (BMW 335i coupe)
  • 3.6L Pentastar DOHC V-6 (Chrysler 300S/Jeep Wrangler)
  • 2.0L EcoBoost DOHC I-4 (Ford Edge)
  • 5.0L DOHC V-8 (Ford Mustang Boss 302)
  • 2.0L Turbocharged DOHC I-4 (Buick Regal GS)
  • 1.6L DOHC I-4 (Hyundai Accent/Kia Soul)
  • 2.0L Skyactiv DOHC I-4 (Mazda3)
  • 3.5L DOHC V-6 HEV (Infiniti M35h)                     

Of those engines, the only ones using conventional multi-port injection rather than DI are the Infiniti hybrid, Chrysler Pentastar and Ford V-8.

The 2012 list also is populated with five 4-cyl. engines, compared with three last year. But five is not a record: In 2010, six 4-cyl. powerplants took Ward’s 10 Best Engines honors.

Forced induction also is well-represented, with four turbocharged and one supercharged powerplant on this year’s list. In each case, forced induction enables a smaller, more fuel-efficient engine to deliver outstanding performance.

“With so many engines featuring gasoline direct-injection and forced induction, we’re pleased to have a list that is rich in technology,” says Drew Winter, editor-in-chief of WardsAuto World magazine. “Plus, every engine reinforces the idea that even fuel-efficient vehicles must be fun to drive.”

Now in its 18th year, the Ward’s 10 Best Engines competition recognizes the latest powertrain technologies that are affordable to most consumers, boost horsepower and torque, sound appealing and integrate well with their respective vehicles.

Audi’s 3.0L supercharged V-6 has been on the list the past two years in the S4 sport sedan and returns for a third consecutive win in the higher-volume A6 sedan. With 310 hp and 325 lb.-ft. (441 Nm) of torque, the A6 can quicken any pulse with a blip of the throttle.

And it’s versatile, too, powering the new Audi A7 5-door sedan and Q7 cross/utility vehicle, as well as Porsche and Volkswagen hybrids.

BMW returns to the list for a second time with the N55 3.0L turbocharged 6-cyl. engine in the 335i coupe, an engine that perfectly illustrates the superior balance and refinement of inline engines and the Bavarian auto maker’s mastery of the architecture’s execution.

With 300 hp and 300 lb.-ft. (407 Nm) of torque, this engine manages better than 25 mpg (9.4 L/100 km) during heavy-footed evaluation by WardsAuto editors in October.

New to the winner’s circle is BMW’s 2.0L N20 turbocharged 4-cyl. engine that dazzles editors in both the Z4 sDrive 28i roadster and larger 528i sedan. With 258 lb.-ft. (350 Nm) of torque in the Z4 and 260 lb.-ft. (353 Nm) in the 5-Series, this stout, compact powertrain packs an impressive 120 hp/L, without sacrificing any of BMW’s stellar vehicle dynamics.

Repeating as a winner is the Chrysler Pentastar 3.6L V-6 that now forms a solid foundation for much of the auto maker’s vehicle portfolio, from the Chrysler 300S flagship sedan and Jeep Wrangler to the Chrysler Group minivans and Dodge Durango SUV.

Even without direct injection, the multipurpose Pentastar returns better fuel economy than a similarly sized V-6 with DI in the competition. Editors manage to get better than 25 mpg, while enjoying outstanding refinement and power.

Ford lands two Ward’s 10 Best Engines honors this year. The EcoBoost 2.0L turbocharged 4-cyl. gets a nod for its uncanny ability to motivate the Edge, a midsize 5-passenger CUV that normally would require 6-cyl. power but does quite fine without it. The same is true for the Explorer CUV, which also uses the 2.0L EcoBoost.

WardsAuto editors get 24 mpg (9.8 L/100 km) in the Edge, which deserves plaudits in this segment.

Ford’s 5.0L V-8 comes back for a second year on the list, this time in the Mustang Boss 302, a 444-hp beast that pays homage to muscle cars of old, but uses modern overhead cam and aluminum construction, as well as performance enhancements such as Twin-Independent Variable Camshaft Timing.

General Motors arrives with an outrageously high specific output of 135 hp/L in the Buick Regal GS, a car that puts to rest the old line about “your grandfather’s Buick.” The 2.0L turbo I-4 delivers exhilarating acceleration and astonishing refinement for such a power-dense engine.

Hyundai spent three years on the list with its excellent Tau 5.0L V-8, but 2012 brings evidence the auto maker can deliver world-class small engines as well.

The new 1.6L DI Gamma 4-cyl. is powering entry level vehicles such as the Hyundai Accent and Kia Rio and demonstrates its versatility in the Kia Soul boxy compact (with a fuel-saving stop/start system) and Hyundai Veloster 3-door coupe.

Mated with an excellent 6-speed manual transmission for our evaluation, this package makes the Accent an easy pick for B-class car shoppers. Priced a shade above $14,000, the Gamma-equipped Accent is an excellent value that will surprise and delight any first-time buyer.

We also were impressed by the engine’s efficiency mated with a 6-speed automatic in the heavier and less aerodynamic Kia Soul.

Another inexpensive and high-tech naturally aspirated 4-cyl. with DI is the Skyactiv 2.0L in the Mazda3 compact. Rated at 40 mpg (5.8 L/100 km) in highway driving with an automatic transmission, the Mazda3 returns better than 34 mpg (6.9 L/100 km) for some editors, despite a sound thrashing.

This engine is both efficient and highly engaging, eager to run in the upper reaches of the powerband. And the price is right: A well-equipped Mazda3 Touring sedan can be had for less than $20,000, including destination charges.

Last only alphabetically, Nissan’s Infiniti luxury brand raises the bar with a hybrid-electric vehicle that is equal parts luxury flagship, sport sedan, fuel sipper and technology showpiece.

The Infiniti Direct Response Hybrid system in the M35h replaces the torque converter in the 7-speed automatic transmission with a single 50-kW (67 hp) electric motor linked to a powerful lithium-ion battery pack that allows frequent decoupling of the engine so the vehicle can run in electric mode at speeds above 70 mph (113 km/h) and easily achieve 30 mpg (7.8 L/100 km), based on WardsAuto testing.

Although pricey, the M35h trumps German luxury hybrid sedans that cost much more.

WardsAutoeditors chose the winners after spending October and November driving 36 vehicles with 34 new or significantly upgraded engines in their routine daily commutes around metro Detroit.

Editors scored each engine based on power, technology, observed fuel economy and noise, vibration and harshness characteristics. There was no instrumented testing.

To be eligible, each engine must be available in a regular-production U.S.-specification model on sale no later than first-quarter 2012, in a vehicle with a base price below $55,000.

Winners from the 2011 competition automatically was eligible and evaluated against the new engines for 2012.

The awards will be presented at a Jan. 11 ceremony in Detroit during the North American International Auto Show.

Complete stories and a video package about the Ward’s 10 Best Engines will be featured Jan. 3 on WardsAuto.com and in upcoming issues of WardsAuto World digital magazine and Ward’s Engine & Vehicle Technology Update newsletter.

tmurphy@wardsauto.com