BELLEGARDE-SUR-VALSERINE, France – Three Dog Night had it right.

The psychedelic rockers once bleated that one is the loneliest number. And it certainly is when used to describe engine displacement.

Expectations are near zero for a 1.0L engine. Especially for consumers old enough to remember Three Dog Night, whose heyday spanned an era when there was “no replacement for displacement.”

But Ford’s 1.0L in-line 3-cyl. EcoBoost engine, launching now in the European-market Focus compact car and in North America two years from now, adds up. It delivers the requisite fuel-economy numbers without subtracting from performance.

The surprise and delight happens with the first push of the start button. The 123-hp engine’s tenor-range exhaust note is robust, not weak or whiny. Ease the car into gear and its tiny mill hooks up with a slightly stiff accelerator that affords welcome feedback on tip-in.

From a standing start, the hatchback launches with predictable but acceptable delay. However, when the 1.0L’s low-inertia turbocharger spools up, it jacks the engine’s peak torque from 125 lb.-ft (170 Nm) to 148 lb.-ft (200 Nm).

The resulting pull is unnatural, considering combustion is taking place in just three chambers.

Zipping through the winding back roads of the Rhone-Alps countryside in eastern France, the engine comes into its own. Despite its diminutive size – the 1.0L’s cast-iron block is so compact it can’t cover a legal pad – the engine churns quietly with engaging smoothness, a rare quality in such a package.

Ford says it achieves added refinement by offsetting the crank pulley from the flywheel so their combined motion mitigates the shaking inherent in 3-cyl. engines.

The fun quotient is realized when modulating the throttle at highway speeds. Temperate tip-ins are met with a pleasing rush, though passing and merging demand aggressive gearing. (Did I mention the shifter could be shorter and more precise?)

Then there is direct injection. EcoBoost is the product of X+Y, if ‘X’ is turbocharging and ‘Y’ is DI.

A byproduct of EcoBoost is formidable fuel economy. Maintaining a steady pace near 65 mph (104 km/h) on a route that spirals upward from the outskirts of Lake Geneva to the ski town of Chambery, the Focus delivers Ford’s promised 56 mpg (4.2 L/100 km).

But traffic slowdowns on the return loop to this sleepy Swiss-border town conspires against the little engine as its performance erodes to levels consistent with Ford’s more powerful 2.0L I-4 –38 mpg (6.2 L/100 km).

Overall, however, the 1.0L EcoBoost exceeds the sum of its parts. Such is the power of ‘1.’

emayne@wardsauto.com

  

1.0L Ford EcoBoost 3-cyl.
Power 123 hp
Torque 148 lb.-ft. (200 Nm)
Bore x stroke (mm) 71.9 x 82.0
Compression ratio 10.0:1
Transmission 6-speed manual
Fuel economy (combined city/highway) 56.5 mpg (5.0 L/100 km)
Vehicle Curb Weight (Ford Focus hatch) 2,820 lbs. (1,279 kg)