Characterization of flow structures during continuous valve opening testing for Swirl Number evaluation in Diesel engine cylinder

As world trucks (busses and industrial diesel engines) producer, Scania AB needs to respect international regulation about pollution and to develop competitive products. To accomplish these goals the engines production needs to respect the design and the tolerances given by the development department. One of the main parameter to be controlled is the Swirl Number, the ratio between the angular momentum and the axial momentum of the flow inside the cylinder. Nowadays the Swirl evaluation test is performed on few sample cylinder heads with stationary test at the central laboratory at the Scania Technical Center in Sweden. Considering both the test mean time (25 min- utes) and the time required to bring the cylinder heads from the production sites to the laboratory, in case of error Scania will suffer large economic losses. The aim of this work was to reduce the test time needed to perform experimental test to evaluate the Swirl Number and the Flow Coefficient. The time reduction was obtained investigating a continuous way to perform the evaluation test. Experimental tests show that continuous tests to evaluate the Swirl Number are possible. With the set up used in this work the test time was 10 minutes, saving the 65% of the original time.