Scholarly record

AN ANALYSIS OF ENERGY AND FUNCTIONAL BEHAVIOR OF HYDROSTATIC TRANSMISSIONS

Teodor Costinel POPESCU, Ana-Maria Carla POPESCU, Alexandru-Daniel MARINESCU, Alina Iolanda POPESCU

Abstract

Hydrostatic transmissions create compliance between rigid functional parameters of a power-machine, e.g. an electric motor, and flexible functional parameters of the work machine, e.g. a crane hoist. Hydrostatic transmissions equip fixed or mobile machinery and guidance systems for: aviation, artillery, wind turbines, hydraulic turbine blades, etc. Any hydrostatic transmission includes at least two positive displacement machines: a pump, called transmission пїЅprimaryпїЅ and a motor, called transmission пїЅsecondaryпїЅ. Hydrostatic transmissions with fixed-displacement pumps and motors are ineffectual as regards energy consumption; primary control (pump displacement control), secondary control (motor displacement control) and mixed control (pump and motor displacement control) improve energy efficiency of hydrostatic transmissions. Mixed control is the most energy-efficient; it requires finding solutions to simultaneously achieve reduction of: - speed variation at the positive displacement motor in the secondary, depending on its load variation; - flow discharged through the safety valve of the pump in the primary, main cause for dissipation of hydraulic energy into heat. An experimental model of a hydrostatic transmission has been optimized as regards energy and functionality; it allowed for primary, secondary or mixed control, through the next two solutions: - for secondary control: the solution of introducing an electronic PID (Proportional Integrative Derivative) controller in the motor speed control loop; - for mixed control: the solution of equipping the pump with pressure regulator and introducing an electronic P (proportional) controller in the motor speed control loop. The analysis performed used as methods mathematical modeling and numerical simulation in AMESim. Results showed: - for secondary control: reduction of about 50% in hydraulic motor speed variation, depending on its load variation, when using the PID controller, against using the P controller; - for mixed control: cancellation of flow conveying through the pump safety valve, if the pump in the primary is equipped with pressure regulator, against transmission with secondary control. There has been achieved a case of hydrostatic transmission control with energy and functional optimal behavior, based on displacement control in both positive displacement machines: it was when the pump was equipped with pressure regulator and a P type electronic controller was introduced in the positive displacement motor speed control loop.

Publication Impact Profile

• Captures
• Mendeley - Readers: 5

PLUMX see details

DOI resolver: doi.org/10.5593/sgem2017/42/s17.006

Publication details

Back to publication list