A method to evaluate the effects of an improved engine thermal management system for a passenger car is proposed. A 'perfect' cooling system was simulated and its effects on the engine thermal status defined with a view to establishing a reference to which different cooling and control system concepts could be compared. A conventional cooling system was then compared to the 'perfect' cooling system to estimate the fuel economy that can be achieved through the adoption of thermal management in a passenger car run on standard driving cycles. Two different cases were hypothesized for the 'perfect' cooling system: a system that warms up the engine instantly and maintains its set point temperature constant, and a more realistic case where the engine is assumed to be adiabatic while warming up. When the temperature set point is reached the two cases converge, because the cooling system is again assumed to be able to maintain its set point temperature constant. The data required for the engine thermal modelling were obtained from a preliminary analysis using the AVL Boost program. Models for all the components of the power train and cooling system were developed and linked to simulate an upper-medium segment passenger car, which was then run on standard cycles. The use of a perfect system means that the simulated fuel consumption reductions constitute theoretical maxima for this car. The results showed that delays in reaching the fully warmed-up condition and/or imperfect control of the engine thermal status both influence fuel consumption. Greater advantages were found in the cycles simulating urban conditions, where engine loads are lowest. These are the conditions in which an improved thermal management system offers the greatest gains, whereas in a conventional cooling system the mean engine temperatures are well under fully warmed up values, oil temperature is excessively low, and friction is greater. Possible directions for research continuation include the collection of experimental data to verify the results of the simulation as well as result generalization by extending the data to different classes of cars.
Numerical method for assessing the potential of smart engine thermal management: Application to a medium-upper segment passenger car
Numerisches Verfahren für die Bewertung des Potenzials des Wärmemanagements eines intelligenten Motors: Anwendung auf einen Mittel- bis Oberklasse-PKW
Applied Thermal Engineering ; 31 , 16 ; 3559-3568
2011
10 Seiten, 14 Bilder, 2 Tabellen, 16 Quellen
Aufsatz (Zeitschrift)
Englisch
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