Degree Type


Date of Award


Degree Name

Master of Science


Agricultural and Biosystems Engineering

First Advisor

Brian L. Steward


Tier 4 legislation and rising fuel prices have increased the attention dedicated to increasing efficiency by designers of off highway vehicles and their components. This paper discusses a methodology for comparing flow loss models of closed circuit axial piston pumps, which are common on off-highway vehicle propulsion systems. Having the best mathematical representation of the flow losses in the pump will aid the designers in understanding the impacts of loss on their vehicle's efficiency. Five flow loss models were compared including the: 1) Wilson, 2) Schlösser, 3) Zarotti and Nevegna 4) Ivantysyn and Ivantysynova and 5) Jeong models. The methodology consists of four steps for the comparison of flow losses: 1) calibration of complete models, 2) parameter reduction through stepwise regression, 3) parameter reduction by reducing multicollinearity and 4) a leave one out cross validation (LOOCV). Of all five, the Ivantysyn and Ivantysynova model clearly calibrated to the measured data set the closest with an root mean squared error of 0.305 L/min. However, in performing cross validation, there does not appear to be a significant difference between the Zarotti and Nevegna, Ivantysyn and Ivantysynova and the Jeong models in their capability to estimate measured flow losses.


Copyright Owner

Samuel Jason Hall



File Format


File Size

114 pages