Application of Electrically Driven Coolant Pumps on a Heavy-Duty Diesel Engine 2019-01-0074
Regarding future GHG limits a reduction in CO2 emissions and consequently fuel consumption is necessary. With respect to the thermodynamic loss analysis of an internal combustion engine, it is recognizable that there is a gap between the indicated efficiency and the brake thermal efficiency. This share is caused by friction losses, where the focus of this research project lays on. In the course of this work the parasitic loss reduction potential of an alternative auxiliary architecture shall be discussed with regard to electrically driven cooling pumps. This is not a novel approach in light duty vehicles, whereas in commercial vehicles a rigid drive of all auxiliaries is standard. Taking into account an implementation of a 48-V power system in the short or medium term, an electrification of auxiliary components becomes feasible. Therefore, the application of electric water pumps (EWP) on a EU VIc certified 6-cylinder in-line heavy duty diesel engine regarding fuel economy in WHTC and real driving as well as aftercooling will be discussed. As the engine has two cooling circuits, one low temperature (LT) cycle for the charge air coolers and one high temperature (HT) cycle as main circuit, these are split in two separate cycles. This layout gives the opportunity to determine the charge air temperature level on demand, which may be lower NOx emissions or exhaust gas heating. Moreover, an operating strategy with respect to a minimum possible coolant flow rate is established and the advantages in the brake thermal efficiency are determined. However, the additional degree of freedom offers not only advantages in CO2 emissions, but can also affect other emission components when it comes to cold start emissions. Future emission tests will include real driving and cold start phases also for heavy duty application, where an optimized thermal management will play a key role.
Christina Granitz, Josef Ratzinger, Helmut Eichlseder, Alfonso Surace
FVT mbH, Graz University of Technology, Industrie Saleri Italo S.p.A
International Powertrains, Fuels & Lubricants Meeting