The three-wheel, 225 mpg plug-in hybrid XR-3 kit car

Robert Q. Riley’s radical high-efficiency designs, concepts and kits have been public for a long time, and have often been viewed as non-mainstream and largely irrelevant by an American population with a highly distorted view of the real cost of cheap petrol. Now his fuel-efficient designs seem suddenly relevant – we desperately need new transportation alternatives that conserve energy and protect the planet’s ecosystem, Riley’s latest creation, the XR-3 plug-in hybrid, is a sleek two-passenger, three-wheel sports car that is expected to return 225 miles per gallon. Designed to be assembled by someone with average mechanical abilities and no prior experience, the all-wheel drive vehicle will be available as a kit or plans for complete do-it-yourself construction. The XR-3 Hybrid is currently under development and is scheduled to debut in June 2007.

“We’ve made a technology leap by designing a super-simple hybrid power system, but ‘technology’ itself was not the main thrust of the project,” said Robert Q. Riley, company president and author of “Alternative Cars in the 21st Century.” “We focused on the power of ‘design’ to define a new category of personal mobility products that are neither automobiles nor motorcycles.”

The XR-3 uses the latest hybrid power system technologies in the most simplified way possible. While the front wheels are powered by a three-cylinder diesel engine, a single rear wheel uses an electric motor run by a lithium-ion battery. The ground provides the connection between the two systems, eliminating the need for a complex electronic and mechanical interface.

Driving on power from its diesel engine, the XR-3 can achieve fuel economy of 125 miles per gallon. However, when the diesel and electric power systems are combined in a hybrid driving mode, fuel economy can exceed 200 miles per gallon over an 80-mile trip.

A simple three-position switch allows the driver to select between battery-only, diesel-only and hybrid driving modes. The diesel engine can remain off for local trips, since power from the advanced lithium-ion battery pack gives the car a battery-only range of up to 40 miles.