Technical Paper
Development of a Heavy Duty Nozzle Coking Test
2013-10-14
2013-01-2674
The diesel engine is still one of the most common and most efficient mobile energy converters. Nevertheless, it is troubled by many problems, one of them being nozzle coking. This is not a new problem; however, due to the introduction of more advanced injection systems and a more diverse fuel matrix, including biofuels, the problem has become more complex. The nozzle holes are also much narrower today than when the problem first appeared and are therefore more sensitive to coking. Two CEC sanctioned coking tests exist for diesel engines, but no universally accepted test for heavy duty engines. In this paper, tests have been performed with B10 doped with 1 ppm zinc on a single cylinder engine, based on a heavy duty engine, with the purpose to develop a simple accelerated coking test. To have relevance to real usage, the test was based on real engine load points from a high power Euro V engine calibration. The coking propensity was studied in an engine speed sweep at max load.
