2007 technology in review

AEI editors look back at some of the most significant engineering and innovation stories of the past year.

Plug-in hybrid vehicles, which travel much further than “conventional” hybrid vehicles on electric power and use an internal combustion engine or fuel cell primarily as a range extender, were big news in 2007. They headlined the North American International Auto Show in January, with General Motors (Chevrolet Volt) and Ford (Airstream) kicking the year off. The more commercially viable Volt (shown) previews a family of modular “plug-in” electric drive systems called E-flex, which GM aims to deploy across its global vehicle range as soon as battery technology is ready. The system will be capable of propelling the series-hybrid Volt up to 40 mi (64 km) on battery power alone and be recharged using a common 110-V electrical outlet. That compares to parallel hybrids such as the Toyota Prius and Ford Escape, which are limited to less than a 2-mi (3-km) range on battery power alone. Based on advanced lithium-ion chemistry that is still in development, E-flex as installed in the NAIAS Volt combines a 1.0-L gasoline engine and 53-kW generator to keep the 136-kW battery pack (with 16 kW-h storage capacity) in a high state of charge. The battery powers a 120-kW electric motor, a spin-off of GM's EV1 program, driving the car's wheels. Total range of a Volt-sized vehicle would be roughly 640 mi (1030 km), delivering the equivalent of 100 mpg or more in urban driving.