Nissan Motor Co said it aims to nearly double the mileage on its first hybrid car developed in-house compared with the gasoline engine version, while keeping costs down with a simple, single-motor system.
Japan's No.3 automaker is due to launch a gasoline-electric Infiniti M sedan, called Fuga in Japan, late this year, lagging rivals Toyota Motor and Honda Motor by more than a decade in offering a proprietary hybrid model.
While admitting to the late start, Nissan said its one-motor, two-clutch system would achieve far better fuel economy, at a much lower technical cost compared with hybrid leader Toyota's complex, two-motor "series parallel" system.
"Typically, carmakers say the fuel economy improvement on their cars using a 'strong' or 'full' hybrid system is roughly 30 percent, while for 'mild' hybrids (like Honda's), it's 15 percent," said Koichi Hayasaki, chief engineer of Nissan's rear-wheel-drive hybrid system.
"We're aiming for an improvement of 60 to 90 percent," he said, adding that the hybrid Infiniti M would have mileage comparable to that of a compact car.
Nissan's hybrid system has a structure similar to that of Volkswagen AG's, mounting an extra clutch that separates the electric motor from the engine to allow for driving using only electric power when the battery is charged.
But Hayasaki said Nissan's unique system enables it to better control the motor by using a lithium-ion battery instead of nickel-metal hydride, which is slower in capturing and discharging energy. Using a lithium-ion battery, he said, eliminates the need for a torque converter, which the Volkswagen group uses on its Touareg SUV, Porsche Cayenne and other hybrids.
"It was a technical hurdle that most hybrid engineers in the
industry believed could not be cleared," Hayasaki said, adding the system took about six years to develop.
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