100mpg Hybrid-Electric Car You build from plansFeatured on the Cover of Mechanix Illustrated Magazine and in the Movie "Total Recall". Plans show gas and electric versions and include twelve 17 x 22 inch drawings, plus an expanded 60-pg photo-illustrated manual.
The idea of a hybrid-electric car naturally evolves from the basic attractiveness of the electric car itself, which, unfortunately, is limited by a shortfall in battery technology. Town Car is based on a VW Beetle chassis, which has been switched to electric power and fitted with an on-board generator powered by a 3 kW, single-cylinder, industrial engine. A 72 volt, 6 kW Baldor dc motor mounts directly to the VW transaxle using an adaptor plate. All gears, including reverse, are operable.
The motor is controlled by an off-the-shelf 600 amp chopper controller. In order to leave room for passengers at the center of the platform, most of the car’s 12, 6-volt lead/acid batteries are located at the ends – six in front, four in the rear, and two between the rear passengers. The body is made of FRP/urethane foam composite.
Town Car’s platform offers opportunities for upgrading, depending upon the user’s needs and the level of sophistication one is willing to build into the vehicle. To evaluate the options, it helps to first understand the conceptual underpinnings of a hybrid vehicle. Initially, the hybrid was envisioned as essentially a battery-electric vehicle with an on-board heat-engine-powered generator (genset) to extend the range. This implied that the genset would be of minimal output in order to bias the system toward battery-electric power and thereby gain the efficiency of using wall-plug electricity.
Today’s thinking runs more toward a systems approach in which battery power and heat-engine power are designed as an integral system that continuously modulates the bias between the two power systems according to the driving schedule. The battery pack serves more as an energy reservoir, similar to a capacitor, to account for peak demands. The genset is typically configured for higher output, usually equaling or nearly equaling the average power required to drive the vehicle over a particular driving schedule. This approach results in a smaller battery pack consisting of batteries designed for maximum specific power, rather than maximum specific energy. The result is a more energy-efficient and cleaner vehicle (compared to conventional vehicles), and better overall performance and range (compared to battery-electric vehicles).
As shown in the plans, Town Car’s power system is configured as a battery-electric urban vehicle with range augmentation from the genset, which is the most straightforward and simple approach. A builder could, however, change battery, motor, and genset ratings, and install an integrated control system, and thereby change the vehicle’s performance profile. Built according to the plans, Town Car has a top speed of 55 mph, a battery-only range of 60 miles, and a genset-assisted range of 100 miles. With the genset operating (it is switched on manually), fuel economy at 35 mph is 100 mpg. By changing battery, motor, and genset ratings/specifications, Town Car’s maximum speed, range, and fuel consumption characteristics can be manipulated to suite different requirements. Town Car’s system is similar to the system in the new Volt.
Town Car was featured on the cover of Mechanix Illustrated magazine, and it was used as a background vehicle in the movie Total Recall.
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