Abstract
To date, Sliding Vane Pump (SVP) technology is one of the most attractive solution in different technical applications thanks to its reliability and compactness and capability to keep a high efficiency even when it is working far from rated condition. In particular, this feature makes the SVP suitable to be employed for the oil circulation (SVOP) in Internal Combustion Engine (ICE) which is characterized by a wide oil flow rates variation, delivered pressure and temperature variation which causes operating conditions of the pump far from the design point. Flow delivered changes in these machines are produced by varying the eccentricity for a mechanical connection with the engine - or by varying the speed of revolution. The mild hybridization of the powertrains calls for a strong development of electrically assisted engine auxiliaries which undoubtedly makes the flow variations easier to be done, but the presence of an electric motor requires some technological choices not fully assessed, a cost increase and a reliability decrease. The paper presents a mathematical model of a SVOP for oil circulation in ICE, suitably validated by a wide experimental activity. The model integrates a mono and zero-dimensional fluid-dynamic analysis and allows to represent the intimate behaviour of the machine. Moreover, it was employed as virtual platform to discuss pros and cons of different flow rate variation strategies and their effect on the efficiency of the SVOP.
Highlights
New regulations in homologation cycles related to CO2 emissions and to other pollutants fixed by the EURO directives have led the scientific research in finding new solutions to increase efficiency and fuel economy in internal combustion engines (ICE)
To date, Sliding Vane Pump (SVP) technology is one of the most attractive solution in different technical applications thanks to its reliability and compactness and capability to keep a high efficiency even when it is working far from rated condition. This feature makes the SVP suitable to be employed for the oil circulation (SVOP) in Internal Combustion Engine (ICE) which is characterized by a wide oil flow rates variation, delivered pressure and temperature variation which causes operating conditions of the pump far from the design point
A surplus of flowrate occurs at high speed and a pressure relief valve (PRV) is necessary in order to maintain oil pressure at a suitable value: this certainly represents a source of power lost
Summary
New regulations in homologation cycles related to CO2 emissions and to other pollutants fixed by the EURO directives have led the scientific research in finding new solutions to increase efficiency and fuel economy in internal combustion engines (ICE). A surplus of flowrate occurs at high speed and a pressure relief valve (PRV) is necessary in order to maintain oil pressure at a suitable value: this certainly represents a source of power lost This issue could be addressed through an electric actuation of the pump [1] which would lead to the downsizing of the pump adding a further degree of freedom. Sliding Vane Oil Pump (SVOP) allows to achieve a high flexibility rate in terms of flow rate variation obtained by varying speed of revolution and eccentricity: devices which improves the priming is achievable as well as the limitation of internal overpressures due to the oil compressibility which is quite variable as a function of operating temperature. The model is fully physically based and mixes a 1D approach during filling and emptying processes through ports and a lumped parameter model to reproduce properties inside closed vanes
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