Given that the traditional four-stroke Otto-cycle engine piston engine only has a thermal efficiency of 25-30 percent, there is clearly still plenty of room for improvement. While most of the green automobile attention in recent years has been focused on electrification, liquid fuels still have about 100 times the energy density of today's best lithium-ion batteries, a difference that probably won't change significantly any time in the near future.
2010 Audi A5 – click above for high-res image gallery
Curve Control on the 2011 Ford Explorer – Click above for high-res image gallery
When the 2011 Honda CR-Z hits the streets this Fall, it will feature the latest iteration of the company's Integrated Motor Assist (IMA) mild hybrid system. The basic concept of IMA hasn't changed since the original Insight debuted in 1999, but it has been refined to improve performance and efficiency while reducing overall cost.
2011 GM HD Trucks - Click above for high-res image gallery
2011 GM HD Truck New Technology – Click above for high-res image gallery
2010 Acura ZDX – Click above for high-res image gallery
2010 Mercedes-Benz S400 Hybrid – Click above for high-res image gallery
2010 Acura TL SH-AWD 6MT - Click above for high-res image gallery