(Tokyo, October 23, 2009) Nissan has finally publicly unveiled its first homegrown hybrid powertrain at the Tokyo Motor Show. The new modular rear wheel drive powertrain will have its first application in the Fuga sports sedan.

Nissan is following a similar path to other recently introduced hybrid systems by designing it to work with conventional automatic transmissions. Previous hybrid drives from Toyota, General Motors and Ford integrate the electric motor/generator(s) into an electronically variable transmission. The older approach is more expensive to build and more difficult to adapt to different vehicles.

The disc-shaped motor-generator is sandwiched between the engine and a seven speed automatic transmission. A pair of clutches are installed on either side of the motor to allow either the engine or motor to be de-coupled from the transmission.

The motor produces 50 kW and 270 Nm of torque. The engine is a 3.5-liter version of Nissan's highly regarded VQ V6 engine that is used in everything from the Altima to the 370Z sports car. For the hybrid application, the engine's variable valve timing has been adapted to allow the engine to operate on an Atkinson cycle.

The late intake valve closing of the Atkinson provides for a shorter effective compression stroke and a longer expansion stroke. The result is increased efficiency although torque output is reduced. The Atkinson is typically used on engines in hybrid applications because the electric motor provides torque to more than supplant what is lost during low speed operation. 

The Fuga hybrid won't go on sale in Japan until Autumn 2010 with the US launch coming some time in 2011 as a 2012. Because the car is still so far from launch, Nissan engineers are still doing calibration of the powertrain, so no final output figures are available at this time.

In non-hybrid applications the 3.5-liter V6 typically has an output of 260-280 hp with approximately 300 Nm of torque. In final form the combined maximum net torque (engine + motor) will probably be limited to approximately 400-450 Nm.

Nissan is taking advantage of the work already been done on lithium ion batteries for its electric vehicle programs by applying it to the hybrid. The capacity of the lithium ion battery pack has not been announced but it appears to use the same modules as the LEAF EV. The higher energy density of the lithium battery means that the pack can be both smaller and lighter than in other current hybrids.

According to Nissan the Fuga will be able to drive on electricity alone at speeds of up to 62 mph, considerably higher than what is available today. The system will also be able to operate in blended mode or internal combustion only as well as providing regenerative braking.

The Fuga will be badged as the Infiniti M35 hybrid when it comes to the US market.