At the same time it is possible to optimise the volumetric efficiency of the engine over the whole operating range, exploiting the degrees of freedom offered by variable valve timing: this means a very favourable torque curve, with 90% of peak torque available from 1800 rpm (290 Nm) and maintained over a broad range (from 1800 rpm to 6250 rpm). The valves are controlled by a roller finger system, with low mechanical dissipation, and hydraulic uptake of tappet play.

Another peculiar feature is the camshaft drive system which uses a primary chain that transmits the drive to the heads via two secondary chains. Tension is provided by automatic hydraulic tensioners which need no maintenance at all during the life of the engine.

The high pressure fuel pump of the direct injection system is mounted on the cylinder head, driven by a camshaft, maintaining the pressure of the injected fuel at 120 bar by a built-in pressure regulator.

The inlet ports and combustion chamber assembly are designed to optimise the air-fuel mixture, to achieve the correct turbulence of the inlet air, forming a homogeneous mixture, for stable, complete combustion that produces fewer pollutants. The four valves per cylinder with diameters of 33.4 mm on the inlet and 28.4 mm on the exhaust guarantee suitable permeability to enhance engine performance.

The volumes and port geometry of the aluminium inlet casing have also been adapted to the high air delivery of the high revs to enhance performance. The electronic throttle assembly with a 72 mm throttle valve is mounted on this casing. And finally, the compression ratio of 11.25:1 guarantees excellent engine performance even with regular 95 octane fuel.

Briefly, the main technical features that distinguish the new 3.2 V6 engine from the previous V6 engine are:

• twin overhead camshaft with low friction drive;

• direct petrol injection;

• double continuous variable valve timing on the inlet and exhaust;

• cylinder head in light aluminium alloy;

• hydraulic tappets with automatic play uptake;

• crankcase in light aluminium alloy;

• maintenance-free timing gear drive chain;

• Poly V automatic tensioner belt to drive the engine accessories;

• throttle valve with electronic drive-by-wire activation;

• single ignition coils;

• low specific consumption and emissions;

• EOBD;

• 4 lambda probes to control emissions;

• double knock sensor to improve knock sensitivity and to optimise peak performance;

• high performance exhaust manifold with built-in pre-catalysts;

• minimum maintenance;

• Euro 4 emissions.

The 3.2 V6 Q4 engine features an exhaust system that envisages a first group of catalysing elements relatively close to the cylinder heads to reduce the emissions level at the start of operation. Two catalysts under the floorpan and four lambda probes complete the system, so that the engine respects Euro 4 limits without adopting special systems such as secondary air or electric heating.

Another feature of the 3.2 V6 Q4 engine is the direct injection system (the fuel is supplied directly to the combustion chamber) whose main advantage is that it improves evaporation and this increases the engine's volumetric efficiency. As a result, the supply of air and petrol is both denser and colder, which allows the compression ratio to be increased to 11.25, even if Euro Super petrol is used, with an octane index of 95 RON; a high compression ratio is useful because it makes it possible to increase both the performance and the energy efficiency of the engine.

And ignition is provided by a single sparkplug per cylinder. Direct injection combined with 4-valve-per-cylinder geometry creates a mix that tends to be more concentrated at the centre of the combustion chamber. The ignition system envisages a single ignition coil per cylinder.

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