Photos: Green cars at Media Days

In its fifth generation, the Toyota fuel cell research vehicle uses the Highlander platform. Engineers replaced steel with aluminum body panels to cut down on weight. The driving experience is very smooth, with the car moving silently forward.

The FCHV doesn't have an internal combustion engine--the wheels are turned by a 90 kilowatt electric motor that feels powerful under acceleration. The FCHV cover shown here protects the power-train brain, the computer which regulates the flow of hydrogen into the fuel cell.

Toyota adapted its Synergy hybrid system for the FCHV, swapping out the internal combustion engine for a fuel cell stack. The stack can send electricity to both the motor and the battery. The car's range is currently over 150 miles, but will almost double with new 10,000psi hydrogen tanks.

Nissan's fuel cell research vehicle uses the X-Trail platform, a car not sold in the U.S. The power-train configuration is similar to the Toyota FCHV, with a 90 kilowatt electric motor turning the wheels. This car also drives very well, and feels like a finished product.

The graphical display is a nice touch, but meant more for public relations than a useful vehicle diagnostic tool. This car can go more than 200 miles, but new high pressure hydrogen tanks will give it a range beyond 300 miles.

Daimler-Chrysler has been conducting its fuel cell research with its F-Cell vehicle, based on the Mercedes-Benz A-class. This car will soon be replaced by a next-generation research vehicle based on the B-class.

Daimler-Chrysler has also been conducting research into plug-in hybrid electric vehicles (PHEVs). This PHEV is based on the Dodge Sprinter van platform, a car generally used for commercial applications, such as cargo transport.

Plugging in the car recharges the batteries, decreasing the amount of time the engine has to crank up. This PHEV uses a special plug that can connect to any 220-volt AC source, charging a lithium-ion battery pack that weighs 352 pounds.

This Sprinter is set up as a shuttle bus, a job requiring frequent stops and well-suited for a PHEV. The PHEV system runs the car under electric power at low speeds, with the internal combustion engine only cranking up when the battery power is low or the speed gets above about 25mph. A compact flash slot is visible on the lower left of the dashboard. It's used to download test data from the PHEV.

As a research vehicle, this PHEV doesn't have a refined power display. Instead, status lights added to the instrument cluster show when it's running emission free, in electric mode, or when the battery is being charged. The Sprinter PHEV has a range of about 20 miles under electric power.