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An Analysis of a Pressure Compensated Control System of an Automotive Vane PumpRyan P Jenkins (6331784) 10 June 2019 (has links)
<div>Pressure compensated vane pump systems are an attractive solution in many automotive applications to supply hydraulic power required for cooling, lubrication, and actuation of control elements such as transmission clutches. These systems feature variable displacement vane pumps which offer reductions in parasitic loads on the engine and in wasted hydraulic energy at high engine speeds when compared to traditional fixed displacement supply pumps. However, oscillations in a currently available pressure compensation system limits the achievable performance and therefore the application of this solution.</div><div>This dissertation presents the development and experimental validation of a lumped parameter model in MATLAB/Simulink of a current pressure compensated vane pump system for an automatic transmission oil supply application. An analysis of the performance of this system using the validated pump model and a developed black box control system model reveals that the low cost solenoid valve present in the control circuit to set the regulation pressure limits the achievable bandwidth to 1.84Hz and causes a significant time delay in the response. To address this limitation, as well as eliminate a non-minimum phase zero introduced by the case study’s control circuit architecture, an actively controlled electrohydraulic pressure compensation system is proposed. This proposed system is explored both experimentally and in simulation making use of the accuracy of the presented variable displacement vane pump model. Significant improvements in the achievable system performance are shown with both a simple PI control law (47% reduction in the pressure response time) and an advanced cascaded model following controller based on feedback linearization (58% reduction in the pressure response time). An analysis of these results reveals that implementing the proposed control system with a 5(L/min)/bar proportional valve with a 20Hz at ±100% (60Hz at ±50%) amplitude bandwidth and a PI control law is an economical path to achieving the best performance improvements for this automotive application.</div>
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VALVE PLATE DESIGN MODEL FOCUSING ON NOISE REDUCTION IN AXIAL PISTON MACHINESAbhimanyu Baruah (5930537) 03 January 2019 (has links)
<p>The advantages of high efficiency,
reliability, flexibility and high power to weight ratio make axial piston pumps
popular for use in a wide variety of applications like construction and
agricultural machinery, off road vehicles and aerospace applications. However,
a major drawback which limits their extensive use in other commercial
applications is noise. One of the important components in axial piston machines
is the valve plate, which influences the transition of the suction and delivery
flows into and out of the displacement chamber. Appropriate design of the valve
plate can play a significant role in influencing the rate of compression and
expansion in the displacement chamber, and hence contribute towards the
abatement of noise in axial piston machines. Furthermore, the relief grooves in
valve plates makes them relatively less sensitive to operating conditions for
the operation of the pump. The high sensitivity of the valve plate design
towards the pressure build up in the displacement chamber and towards the noise
sources are big motivation factors towards rigorously exploring the design
space to find suitable designs to meet the objective of noise reduction. This
motivates the development of an advanced computational tool, colloquially
called 'MiNoS', where a powerful optimization algorithm has been combined
together with a novel parametrization scheme for valve plate design and a 1D
simulation model of swash plate type axial piston machines to find optimized
designs which can contribute towards noise reduction in swash plate type axial
piston machines. Furthermore, incorporation of the appropriate constraint also
helps in avoiding designs susceptible to the onset of cavitation in the
displacement chamber. A case study performed using the developed computational
tool has been shown later in this work.</p>
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