As the roads fill with the quiet, environmentally-friendly hybrids, most people are now aware of the premise. The electric half of the hybrid starts the vehicle going, then the gas half kicks in once it gets to a certain speed. While the basic concept is easy to understand, there’s a lot more to it than that.

This graphic by AutoMD breaks down the ins and outs of hybrids, giving us a glimpse of what really makes the engine go. Gas prices rising makes purchasing a hybrid a potentially valid option.

“We thought that the interest in the Prius had hit its peak last year, but it’s gone beyond anything we could have imagined,” said Glenn Boler at Maryland Toyota. “We can’t keep enough in stock.”

Unless there’s a turn in gas prices, the trend should continue indefinitely. Click the infographic to enlarge.