With customers demanding it — and the feds mandating it — car makers are doing anything and everything to squeeze more miles from a gallon of fuel. Hybrids, plug-in hybrids, diesels, turbos, low-rolling resistance tires, moonbeams, pixie dust, you name it and car makers are trying it.

Like everyone else, Mazda, too, is full bore into the efficiency game. But unlike a lot of the other guys, Mazda figures there's still life in the good old internal-combustion gasoline engine. So, for 2012, the company has come up with what it calls Skyactiv Technology, which it has introduced in its Mazda3 sedan and five-door hatchback.

With Skyactiv, Mazda engineers, in essence, have put every aspect of the gasoline engine under the microscope, identified inherent inefficiencies, and then massaged it here, tweaked it there, improved it over there and re-engineered it down there to wring out every iota of mileage possible without resorting to complex hybrid hardware, handling-compromising low-rolling-resistance tires or performance-sapping CVT transmissions.

Instead, Skyactiv employs lighter engine blocks, high compression, direct fuel injection, variable-valve timing, exotic exhaust plumbing and low-friction moving parts in both the engine and in the Mazda3 Skyactiv's lighter six-speed transmissions, both manual and automatic.

The result is a 155-hp, 2.0-liter Skyactiv four-banger whose EPA numbers are roughly 18 percent better than the company's old 148-hp 2.0-liter four, which, by the way, remains available on the Mazda3, as does a 167-hp, 2.5-liter I-4.

The official EPA ratings for Mazda3 Skyactiv models are:

Automatic sedan: 28 city/40 hwy

Manual sedan: 27 city/39 hwy

Automatic hatchback: 28 city/39 hwy

Manual hatchback: 27 city/38 hwy

With our Skyactiv hatchback, equipped with the six-speed manual, we averaged 34 mpg over a total of 330 miles. That included a 120-mile round-trip on the interstate to Ste. Genevieve, Mo., during which we got just what the EPA promised: 38 mpg.

Even with such lofty numbers — including the magic 40 mpg for the automatic sedan — Mazda3 embraces the company's zoom-zoom philosophy. Skyactiv's 155 hp is better than average for the segment while the 3's tautly sprung suspension, quick steering and urgent four-wheel-disc braking provide a satisfying driving experience.

With Skyactiv, you don't give up a lot in driving satisfaction to get high mpg, as frequently is the case with hybrids.

Beyond that, the Skyactiv Mazda3 has all the virtues and peccadilloes of every other Mazda3. Leg room is only OK in front, downright tight in back; wind noise is notable at highway speed; the five-door's liftgate is awkward to use due to a thumb button over the finger grip; and the front-end styling shows a Bozo grin that makes the car look too happy to have good sense.

But the driving is fun, the fuel economy is lofty, the five-door offers all the convenience of a small wagon and the price is right: $19,745 to start for the Skyactiv five-door, about a grand less for the sedan.