2. Experimental development of DI diesel engines

2.1 Wind tunnel characterization of cylinder heads

We have seen [3] that mixing the fuel, injected into the bowl through several holes, and the air, requires the air to rotate. This rotation is generated as the piston descends, thanks to the position and shape of the intake duct(s) in the cylinder head, and then amplified during compression inside the bowl (conservation of angular momentum).

To find the optimum swirl for combustion, it is therefore necessary to quantify it by means of a wind tunnel measurement, which we will describe below.

On the other hand, the aim is to introduce as much air as possible into the chamber, and to do this we need a cylinder head that is as permeable as possible; this permeability will also be characterized...