In principle, it is the engine-block of the respective 1,6 litres Diesel engine with the same measurements for the bore and the stroke. What is unusual in a Diesel engine, is the square-engine principle as opposed to the long-stroke engine. The advantage is: Lower friction loss.
Only the cylinders 1 and 3 have counterweights and both outsides have greater dimensions. Herewith, one attempts to compensate for the 1st order mass-forces and -torques. Particularly the latter, are responsible for any tipping movement around the transverse axis. The drive-wheel for the chain to the offset shaft and the oil-pump are mounted up front, on the crankshaft.
In contrast to the engine block, the cylinder head is made of aluminium. The timing belt, coming up from below, drives the exhaust camshaft, which then, through gear-wheels which are without play, drives the inlets. The valve clearance offset at the pivot of the roller cam followers makes sure that there are only little masses to be moved.
The oil-pump and the offset shaft are summarised into one module below the crankshaft. This is driven by a hydraulically tensioned chain. With the crankshaft RPM, the offset shaft also reduces the 1st order mass-forces and the torque. The reduction of all the mass-forces, is so complicated in a three cylinder engine, that the reduction of one cylinder is no longer worthwhile.
Apart from driving the camshaft, the above mentioned timing belt also drives the cooling- and the high pressure pump.
In addition, another drive-belt for the generator and possibly also the air conditioners compressor, is also necessary. It's tension-pulley is spring loaded.
The oil filter, the oil cooler and the pressure regulating valve are summarised into one element, which is flanged onto the side of the engine block.
Apart from the normal cooling circuit, another one, with a lower temperature, is necessary to cool the recycled exhaust gasses. It has its own, electric, permanently running pump and takes it's coolant from the coldest area of the normal cooling circuit, during cold running, primarily directly from the unused radiator.
The cooling of the recirculated exhaust gas provides a higher recirculation rate, thus less nitrogen oxide in the exhaust gas. In the exhaust gas system there is a broadband sensor and in the intake system (see picture below), a regulating flap. Thus, the ideal recycling rate can be regulated.
For a Diesel engine, the intake-manifold is somewhat complicated, because here, there are swirl-flaps for each cylinder, which depending on the working condition, provide for an ideal swirling in the cylinder though a stepping motor.
The common rail system shows, with it's single-piston pump, it's magnetic injectors, the supply pressure of 5 bar and the injector pressure of between 230 and 1800 bar, nothing particularly special.
The turbocharger with a variable turbine-geometry and intercooler is also the technical standard in Diesel engines.
Indeed, one of its highlights is the knocking sensor. It is, the same as it would be in a petrol engine, bolted on near to the second cylinder, where it can pick up all the noises possibly created in the individual cylinders. In this case, it also announces any knocking, more precisely, any change in the noises, from which the engine control device can give out information concerning the combustion timing.
An interesting point is, how the control device manages to distinguish the combustion noises from other engine sounds. To do this, every now and then it records the noises coming from one particular cylinder when the piston is in the vicinity of TDC and when it's near to BDC. In a three cylinder engine, no two cylinders inject simultaneously at BDC. From this the control device learns, also when changes take place in an ageing engine, to distinguish the noises.
The control device can thus, correct the timing control of the respective magnetic valve and at the same time register the effects. It can even determine and store the time between the pre-injection and the main injection for the respective magnetic valve, just in case the knocking sensor breaks down. 07/14