Intake port shut-off for optimum air supply

The combustion air subsequently flows into the charge-air distributor module, which supplies air to each cylinder in a uniform manner. Built into the distributor module is an electrically controlled intake port shut-off which allows the cross-sectional area of each cylinder's intake port to be smoothly reduced in size. This alters the swirl of the combustion air in such a way as to guarantee that the charge movement in the cylinders is set for optimum combustion and exhaust emissions over the full spectrum of engine loads and rev speeds.

Rear-mounted camshaft drive

The list of the new four-cylinder diesel engine's principal innovations also includes the rear-mounted camshaft drive. This allows statutory pedestrian protection requirements to be fulfilled when the engine is installed lengthways with the bonnet rising towards the rear. The vibration stimuli originating from the crankshaft are furthermore lower on the rear face of the engine than at the front, which benefits the engine's exceptionally smooth running.

The valve timing mechanism is another new development and reduces friction at the 16 intake and exhaust valves, which are controlled by one overhead intake shaft and one overhead exhaust shaft acting via cam followers featuring hydraulic valve clearance compensation. The camshaft, Lanchester balancer as well as the ancillary assemblies are driven by a combination of gearwheels and just a very short chain drive. It was possible to reduce the increased noise levels usually associated with a gearwheel drive by carrying out painstakingly detailed refinement.