Overview: Infiniti M30d & M35h

We have described the Renault-Nissan-Infiniti V9X three-litre diesel elsewhere on these pages. It is intended for use in a variety of the group’s products. In the interest of rigidity, the block is cast from compacted graphite iron (CGI) and features an unusual 65° V angle. A single turbocharger is incorporated inside the V.

The M-series Infiniti is a marketed as sporting saloon in the mould of BMW’s Fünfer. Like the Bavarian, the engine is mounted in a front-mid position. Comparative figures for the two cars are given in the data table below.

M35h

This is Infiniti’s first hybrid. A 3.5-litre V6 petrol engine is combined with a 68PS electric motor that’s built in to the seven-speed automatic transmission. Infiniti calls its hybrid drivetrain Infiniti Direct Response Hybrid.

The M35 hybrid uses the same front-engine rear-drive layout seen on conventional M-series cars. In the hybrid, two clutches are used: one, a dry-plate unit, is between the petrol engine and the transmission (which incorporates the electric motor); the second — wet-plate — clutch is downstream of the transmission. This is a part of the transmission assembly and clearly disengages drive completely, allowing the M35h to operate without a torque-converter for its automatic gearbox.

At very light loads, when the petrol engine is out of use, the first clutch (engine-to-transmission) is disengaged; drive is from the electric motor to the rear wheels, obviously with the rear clutch engaged. Similarly on overrun at higher speeds, the petrol engine can be shut off, the front clutch disengaged and the car’s kinetic energy fed straight into the motor in its capacity as a generator. Under higher loads, both clutches are engaged — except during gearchanges.