Ramped versus square injection rate experiments in a heavy-duty Diesel engine

Robbert C. Willems, Frank P.T. Willems, Tony Simpson, Bogdan A. Albrecht, Niels G. Deen, L.M.T. Somers

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CO 2 regulations on heavy-duty transport are introduced in essentially all markets within the next decade, in most cases in several phases of increasing stringency. To cope with these mandates, developers of engines and related equipment are aiming to break new ground in the fields of combustion, fuel and hardware technologies. In this work, a novel diesel fuel injector, Delphi's DFI7, is utilized to experimentally investigate and compare the performance of ramped injection rates versus traditional square fueling profiles. The aim is specifically to shift the efficiency and NO x tradeoff to a more favorable position. The design of experiments methodology is used in the tests, along with statistical techniques to analyze the data. Results show that ramped and square rates- A fter optimization of fueling parameters-produce comparable gross indicated efficiencies. Tests were carried out at 1200 and 1425 rpm; for the latter engine speed peak efficiency was attained at considerably lower NO x levels by applying a ramped injection rate. Particulate matter emissions, on the other hand, are generally lower with the use of square profiles. Heat release analysis further reveals that ignition delays in ramped rate operation are quite long, hinting at vastly different spray behavior. The relatively low loads applied in this work only sustain the delays further. Altogether, this causes the potential of the rate shaping capabilities to be underexploited, as direct control over the burn rate is limited with the combustion system used in this work. The results emphasize the need to carefully select ramp slopes for a particular engine geometry, load and speed point, and additional operating parameter settings.

Original languageEnglish
Title of host publicationSAE World Congress Experience (WCX 2020)
PublisherSociety of Automotive Engineers (SAE)
Number of pages15
Publication statusPublished - 14 Apr 2020

Publication series

NameSAE Technical Paper


This work was funded by the Dutch Technology Council (NWO), domain Applied and Engineering Sciences (TTW) (Heat2Control; project number 12678). The authors particularly wish to thank Dan Mellors for his assistance in setting up the injector controls, Nicholas More for providing the injection rate data and Theo de Groot for his help with preparing the engine setup.

FundersFunder number
Dutch Technology Council
Nederlandse Organisatie voor Wetenschappelijk Onderzoek12678


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