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.

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Infiniti M30d.

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.

Infiniti M35h hybrid.

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.

A small, lightweight 1.3kWh lithium-ion-manganese battery-pack is used, sacrificing electric range in the interest of mass-reduction. The M35h is no featherweight at 1885kg, but it’s not much heavier than its siblings. The battery-pack is Nissan’s laminated ‘coffee-bag’ type, favoured for its relative ease of thermal management.

The M35h’s transmission is a version of Infiniti’s seven-speed Adaptive Shift Control (ASC) automatic transmission; the significant difference over the ASC transmission used in other Infiniti models is the lack of a torque converter.

The car’s electric motor is rated at 68PS and 270Nm. Curiously, the torque rating is stated as peaking at 1000rpm, in sharp contrast to most electric motors which achieve their maximum torque at the first revolution. As is the case with all series-parallel hybrids, the motor can work by itself or to boost the combustion engine. It also acts as a generator during overrun.

Infiniti M35h hybrid power flow display.

The power steering set-up is electro-hydraulic, with on-demand assistance.

The brakes use the electric drive motor to operate the brake cylinders — a genuine novelty, so far as we know. The system is called Electric Driven Intelligent Brake: when the driver presses the brake pedal, the necessary braking force is maintained while the hydraulic pressure of the friction brake is controlled to help maximise the energy regeneration of the hybrid motor. Also worthy of note is that double-tube dampers are used. The power-steering, on the other hand, is rather old-hat, with electro-hydraulic assistance rather than a direct electric set-up.

Infiniti
M30d
BMW
530d
Cylinders 6V 6I
Valves 4 4
Bore/stroke 84.0/90.0 84.0/90.0
Swept volume 2993cc 2993cc
Compression
ratio
16.0:1 16.5:1
PS/rpm 238/3750 245/4000
Nm/rpm 550/1750 540/1750
0-100km/h 6.9 6.3
Maximum
speed
155 155
Urban MPG
(l/100km)
27.4
(10.3)
36.6 †
(7.7) †
Combined MPG
(l/100km)
37.7
(7.5)
46.3 †
(6.1) †
CO2 g/km 199 160
Emissions EU5 EU5 (1)
Transmission A7 M6 (A8) †
Driven wheels Rear Rear
Fuel tank 80l 70l
Kerb mass 1845 1715
PS/t 129 142
Nm/t 298 314
Length 4945 4899
Width 1845 1860
Height 1500 1464
Wheelbase 2900 2968
Track: front
Track: rear
1575
1570
1600
1627
Tyres 245/50R18W
245/40R20W *
225/55R17W
CdxA 0.27x2.38m² 0.28x2.35m²
† BMW fuel consumption figures for eight-speed automatic version.
(1) EU6 available.
Infiniti M30d M37 M35h
Cylinders 6V 6V 6V
Valves 4 4 4
Bore/stroke 84.0/90.0 TBA TBA
Swept volume 2993cc 3696cc TBA
Compression
ratio
16.0:1 TBA TBA
PS/rpm 238/3750 320/7000 306/TBA
Nm/rpm 550/1750 360/5200 350/5000
Motor PS 68
Motor Nm/rpm 270/1000
Battery: type
— capacity
Pb/H+
Pb/H+
Li-ion/Mn
1.3kWh
Maximum speed 155 155 155
Maximum speed
(electric power)
50
Electric range 1.2
0-100km/h 6.9 6.2 5.9
Urban MPG
(l/100km)
27.4
(10.3)
19.0
(14.9)
TBA
Combined MPG
(l/100km)
37.7
(7.5)
27.7
(10.2)
38.6
(7.3)
CO2 g/km 199 235 170
Emissions EU5
Transmission A7
Driven wheels Rear
Fuel tank 80l
Kerb mass 1845 1715 1885
PS/t 129 186 162 (1)
Nm/t 298 210 329 (2)
Length 4945
Width 1845
Height 1500
Wheelbase 2900
Track: front
Track: rear
1575
1570
Tyres 245/50R18W
245/40R20W *
CdxA 0.27x2.38m²
0.28x2.38m² *
* On S and S Premium grades.
(1) Petrol engine only (i.e., sustained).
(2) Petrol and electric power combined (i.e., transient).
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