Don't hum the requiem for the gasoline engine just yet. MIT brainiacs say it's easier than imagined to flip a car between the usual gas-guzzling state to a low-pollution, ultra-efficient mode.

The researchers have tested a system that can run on a quarter less than the usual amount of gas without needing any fancy fuel. With the flick of a switch, the setup alternates between regular, spark-triggered combustion and experimental homogeneous charge compression ignition.

In the latter system, premixed fuel and air combust when compressed, spewing less soot and NOx from the engine. Volvo has explored the hybrid technology, but many kinks would need to untangle before you could get behind the wheel.

If car makers adopted such hybrid gasoline ignitions, the petroleum wouldn't get any cleaner, but less of it would be used, potentially adding a few miles per gallon of efficiency to a car. That might keep the grins up at oil companies and gas stations -- but in dreamland, only for a fleeting moment, as the world weans off of fossil fuels. Right?

This and other stopgap car-greening measures of now and the near future are giving people more driving options than ever. What's more interesting -- the novelty of this innovation, or that it's reaching the not-quite-there-yet phase of development more than a century after Daimler and Benz got props for the modern gas engine?