The result is a compact, architecturally stiff and refined unit that by itself delivers two of Infiniti’s design goals: high levels of refinement and no loss of chassis balance. In tests, Alliance engineers have determined that the V9X engine has the lowest 250 Hz and 500 Hz vibrations of all the benchmarked engines.
The main dimensions of the unit are:
Cylinder arrangement V, six cylinders
Displacement 2993cc
Bore x stroke 84 x 90 mm
Bore pitch 92 mm
Vee angle65 degrees
To ensure it fitted under the bonnet of both the EX and FX models, there are a number of significant differences between the Infiniti engine and its ancillaries and the version used in front-wheel drive applications. A number of changes also had to be made to the engine bays of the EX and FX.
As used in Infiniti models, the engine has a different cylinder block, a new design of crankshaft as well as new or revised intake manifold, fuel injection system, exhaust gas recirculation, turbocharger, oil sump and manifold catalyst. It is tuned differently, too, for more responsive performance and is ‘dressed’ differently, in keeping with the visual identity and design expression of the Infiniti brand.
Differences between petrol and diesel versions of the EX and FX models are equally far reaching and include a new front subframe, different front bumper designs to enhance air flow into the engine bay as well as redesigned sheet metal within the engine bay to house additional radiators needed for cooling.
The next phase of the engine’s development was to achieve the high levels of performance demanded by Infiniti owners. The result is a clean sheet design that takes current direct injection technology to a new level. Combustion chamber design has been optimised to improve the balance between emission levels and fuel efficiency and the compression ratio has been lowered to 16:1 to benefit not just economy and emissions but also noise, vibration and harshness (NVH).
The depth of the cone-shaped valve pockets have been reduced and a mini-sac seven-hole injector nozzle adopted while the bowl diameter has been widened and the spray angle adapted accordingly for a better swirl effect at the same time as reducing thermal losses. Internal engine friction is reduced by the use of ultra smooth components such as the micro-finished forged steel used for the crankshaft.
Class leading levels of torque and highly competitive specific power outputs are delivered thanks to the adoption of a comparatively large single turbocharger, which is mounted within the vee of the engine, an intercooler and the use of the latest generation of Bosch common-rail fuel injection. This system incorporates piezo injectors and operates at 1800 bar.
Power output is bang on target at 175 kW (238 PS) while the class-leading torque output of 550 Nm (for rear and four-wheel drive applications) is better than the target. Better still, peak torque is achieved from as low as 1,750 rpm and is available all the way to 2,500 rpm, while as much as 500 Nm is available from a mere 1,500 rpm. Idle speed is an exceptionally low 650 rpm with none of the NVH usually associated with a diesel.
The result is strong low-end performance with comfortably refined delivery. Throttle response is exemplary and although noise is kept to a minimum, special tuning of the exhaust note provides a pleasantly sporting note at about 2,500 rpm under hard acceleration.
Engine refinement is complemented by Infiniti’s smooth seven-speed automatic transmission, standard on both EX and FX, which has been tuned to take full advantage of the high levels of torque.
“Whether at idle or at 2,000rpm such is the refinement of the new diesel engine that the only way a driver will know what’s under the bonnet is by looking at the rev counter and seeing where the red line falls,” said Wright.
Performance and construction
Power238 PS/ 175 kW
Torque 550 Nm from 1,750-2,500 rpm
Intake system VN turbocharger and intercooler
Injection system Common rail, 1800 bar and piezo injectors
Compression ratio 16:1
Camshaft drive DOHC, chain and pinion with mechanical lash adjuster
Valve driveRoller finger follower and hydraulic lash adjuster
Valves per cylinder 4
Cylinder head/block Aluminium/CGI
photo:Nissan
The main dimensions of the unit are:
Cylinder arrangement V, six cylinders
Displacement 2993cc
Bore x stroke 84 x 90 mm
Bore pitch 92 mm
Vee angle65 degrees
To ensure it fitted under the bonnet of both the EX and FX models, there are a number of significant differences between the Infiniti engine and its ancillaries and the version used in front-wheel drive applications. A number of changes also had to be made to the engine bays of the EX and FX.
As used in Infiniti models, the engine has a different cylinder block, a new design of crankshaft as well as new or revised intake manifold, fuel injection system, exhaust gas recirculation, turbocharger, oil sump and manifold catalyst. It is tuned differently, too, for more responsive performance and is ‘dressed’ differently, in keeping with the visual identity and design expression of the Infiniti brand.
Differences between petrol and diesel versions of the EX and FX models are equally far reaching and include a new front subframe, different front bumper designs to enhance air flow into the engine bay as well as redesigned sheet metal within the engine bay to house additional radiators needed for cooling.
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The next phase of the engine’s development was to achieve the high levels of performance demanded by Infiniti owners. The result is a clean sheet design that takes current direct injection technology to a new level. Combustion chamber design has been optimised to improve the balance between emission levels and fuel efficiency and the compression ratio has been lowered to 16:1 to benefit not just economy and emissions but also noise, vibration and harshness (NVH).
The depth of the cone-shaped valve pockets have been reduced and a mini-sac seven-hole injector nozzle adopted while the bowl diameter has been widened and the spray angle adapted accordingly for a better swirl effect at the same time as reducing thermal losses. Internal engine friction is reduced by the use of ultra smooth components such as the micro-finished forged steel used for the crankshaft.
Class leading levels of torque and highly competitive specific power outputs are delivered thanks to the adoption of a comparatively large single turbocharger, which is mounted within the vee of the engine, an intercooler and the use of the latest generation of Bosch common-rail fuel injection. This system incorporates piezo injectors and operates at 1800 bar.
Power output is bang on target at 175 kW (238 PS) while the class-leading torque output of 550 Nm (for rear and four-wheel drive applications) is better than the target. Better still, peak torque is achieved from as low as 1,750 rpm and is available all the way to 2,500 rpm, while as much as 500 Nm is available from a mere 1,500 rpm. Idle speed is an exceptionally low 650 rpm with none of the NVH usually associated with a diesel.
The result is strong low-end performance with comfortably refined delivery. Throttle response is exemplary and although noise is kept to a minimum, special tuning of the exhaust note provides a pleasantly sporting note at about 2,500 rpm under hard acceleration.
Engine refinement is complemented by Infiniti’s smooth seven-speed automatic transmission, standard on both EX and FX, which has been tuned to take full advantage of the high levels of torque.
“Whether at idle or at 2,000rpm such is the refinement of the new diesel engine that the only way a driver will know what’s under the bonnet is by looking at the rev counter and seeing where the red line falls,” said Wright.
Performance and construction
Power238 PS/ 175 kW
Torque 550 Nm from 1,750-2,500 rpm
Intake system VN turbocharger and intercooler
Injection system Common rail, 1800 bar and piezo injectors
Compression ratio 16:1
Camshaft drive DOHC, chain and pinion with mechanical lash adjuster
Valve driveRoller finger follower and hydraulic lash adjuster
Valves per cylinder 4
Cylinder head/block Aluminium/CGI
photo:Nissan