The Infiniti M35 Hybrid, known in the Japan-market as the Nissan Fuga, is not Nissan’s first hybrid — that distinction goes to the Altima Hybrid. The M35 Hybrid is Nissan’s first hybrid developed in-house. The Altima hybrid uses a customized version of Toyota’s hybrid technology.
But unlike the Altima’s system, Nissan claims its new setup is more technologically advanced and less complex at the same time. For example, Nissan’s single electric motor arrangement is reportedly close to 70 pounds lighter than Toyota’s double-motor system.
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.
The car will operate with a one-motor, two-clutch system and a lithium-ion battery. This will allow the engine to idle more frequently when the car isn’t moving, Koichi Hayasaki, chief engineer of Nissan’s rear-wheel-drive hybrid system told Reuters.
“We’re aiming for an improvement of 60% to 90%,” in mileage Hayasaki, said. Testing showed that the engine is stopped around half the time during city driving, Hayasaki said.
Nissan’s hybrid system has a structure similar to that of Volkswagen’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.
By having fewer components, Hayasaki said, Nissan’s hybrid system was roughly 30 kg (66 lb) lighter than Toyota’s series parallel system, which mounts two electric motors and two inverters, which make up the bulk of a hybrid system’s cost.
Nissan’s engineers wanted a simple mechanical and electrical architecture that could later be used in front drive applications, too. Thus, they decided to use a single electric motor-generator rather than the usual two or more employed on most premium hybrids.
For conventional open-road driving, both clutches are closed and the V-6 engine – adapted to run on the Atkinson cycle to suit hybrid operation – drives directly through to the planetary transmission. The rear clutch, between the electric motor and the transmission, is a wet clutch allowing a degree of slip on take-up so as to smooth its operation. In this medium-speed condition, the motor can also operate as a generator to recharge the lithium ion battery.
Since the M35 hybrid is a 2012 model, no performance, economy, or CO2 emission figures have yet been issued.
As part of its drive to reduce carbon dioxide emissions from its cars, Nissan is planning to also launch fuel-efficient 3- and 4-cylinder gasoline engines and stop-and-start technology this business year.