You've gotta hand it to automakers. However tight the noose of emissions regulations and MPG targets gets, the engineers always find a way to wriggle free with ever more impressive fuel economy figures.

Mitsubishi's way of meeting ever tighter targets is to update its MIVEC variable valve timing and lift system, and adding automatic stop-start technology in several current models.

The Outlander Sport compact SUV, Lancer sedan and Lancer Sportback are all set to receive the new 138-horsepower 1.8-liter gasoline engine which Mitsubishi claims brings about a 12 percent improvement in fuel efficiency, when measured on the Japanese 10-15 mode cycle.

This should equate to a 2-3 MPG increase over the Outlander Sport's current 25 MPG city, 31 MPG highway and the Lancer's 25 city, 33 highway rating.

MIVEC works by varying the valve lift, duration and timing according to what's being demanded of the engine, allowing it to operate at maximum efficiency whether you need quick pick-up in city driving or you're at a constant speed on the freeway. In principle, its very similar to Toyota's VVT or Honda's i-VTEC systems, among others used by other carmakers.

Stop-start is equally familiar though its effects on fuel efficiency are more difficult to show on the current EPA test cycle. Several manufacturers use the technology and claim large benefits particularly if you spend a lot of time in heavy traffic, but it makes little difference to EPA numbers.

The new system has been developed for use with continuously variable transmissions (CVT) and combined with the new MIVEC system, allows for less fuel to be used when the engine re-starts. Want to know more about stop-start systems? Here are five things you need to know.

The new engine is being launched in the Japanese market this week, and U.S. introduction should follow.

Gasoline engines? There's life in the old dog yet.


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