Tokyo R&D IZA Electric Car
By Ron Cogan
Most of the high-profile news in the electric vehicle arena was made early on by the GM Impact prototype that debuted at the 1990 Los Angeles Auto Show. Even as the Impact was stealing headlines, others were picking up the pace in EV development. Most of the major automakers were involved, but other research and development activities outside of the auto manufacturers’ labs were also taking place. One that stood out at the time was the IZA electric vehicle prototype by Tokyo R&D, which was shown at the 1991 Tokyo Motor Show. This vehicle illustrated the international competitiveness that would manifest in the EV field over the coming years. Here, we reprint our report just as it ran in Green Car’s March 1992 issue.
TOKYO’S IMPACT ON ELECTRIC CARS
ORIGINALLY PUBLISHED MARCH 1992 Sleek and slippery like General Motor’s Impact prototype, the IZA easily garners attention from anyone in its vicinity. It did this consistently at the Tokyo Motor Show. Green Car editors found it to be among the most formidable EV research efforts showcased by Japanese interests.
The IZA is principally sponsored by Tokyo Electric Power Co. (TEPCO) as an “experimental study vehicle.” The company began with a clean slate in 1988, commissioning Tokyo R&D Ltd. To design the body and Meidensha Corp. to handle motor and inverter development. Technical guidance was provided by the EV Research Organization and Professor Yoichi Kaya of the University of Tokyo.
Some interesting comparisons can be drawn with GM’s Impact prototype. Both aerodynamic EVs achieve an impressive 0.19 coefficient of drag, each relying heavily on wind-tunnel design and high-tech construction techniques. The Impact uses a fiberglass-reinforced monocoque arrangement, while the IZA integrates a carbon fiber reinforced plastic body over an aluminum chassis. Height and width dimensions are nearly identical. Certain specifications vary widely since the Impact is a two-seater and the IZA a 2+2. The IZA’s body and wheelbase are longer (an additional 29 inches and 13 inches, respectively), and curb weight is heftier by 1268 pounds.
One of the most interesting features found on the IZA is its brand of motivation. Meidensha Corp. integrated a direct-drive system with each wheel connected to a DC brushless motor. Japan Storage Battery Co. installed 24 nickel-cadmium (NiCad) batteries to create a 288-volt, 28.8 kWh powerpack for the four-wheel drive powertrain. This battery system weighs in at a substantial 1170 pounds, one-third of the car’s overall weight. Bridgestone Ecology 205/50R17 low-rolling resistance radials were mounted to modulate road friction and unsprung weight. Endurance testing on Meidensha’s chassis dynamometer in October 1991 indicated a 343-mile range at a steady speed of 25 mph, and a 169-mile range at 62 mpg. Indicated top speed is 110 mph, the same as that of the Impact.
The car incorporates a variety of comfort and convenience features including power steering, power windows, and power-assisted brakes. An inverter-controlled heat pump air conditioning system is also used. Its interior is simple but stylish, with a smoothly-contoured dashboard placing all controls easily within reach. Minimal instrumentation is housed within a very small rounded cluster directly in front of the driver.
TEPCO sources advise Green Car that additional IZA models are not planned at this time. In the meantime, the company is conducting further tests and working to secure a license plate for highway operation.
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