with series spool connection.Figure 20.13 Simplified open center architecture for excavators.21 Chapter 21Figure 21.1 Principle of load sensing control of multiple actuator.Figure 21.2 Energy plot for the LS system of Figure 21.1 assuming p U1 > p U2 ...Figure 21.3 Multi‐actuator LS system with LS pump and LS valve.Figure 21.4 LS system with four actuators: the shuttle network comprises thr...Figure 21.5 Simplified representation of the LSPC pre‐compensated concept.Figure 21.6 Energy plot for the pre‐compensated LS system of Figure 21.5, as...Figure 21.7 Detailed representation of the Power loss term for the pre‐compe...Figure 21.8 Multi‐actuator pre‐compensated PCLS system.Figure 21.9 Cross‐section and equivalent schematic of a pre‐compensated dire...Figure 21.10 Detailed view of the compensator.Figure 21.11 Simplified representation of the LSPC post compensated concept....Figure 21.12 Energy plot for the post compensated LS system of Figure 21.11,...Figure 21.13 Detailed representation of the Power loss term for the post-com...Figure 21.14 Schematic of a two section post compensated valve.Figure 21.15 Section view of a post‐compensated proportional directional con...Figure 21.16 Basic circuit for the pre‐compensated LSPC.Figure 21.17 Simplified representation of the LSPC post compensated concept....Figure 21.18 Post‐compensated LS independent metering system.Figure 21.19 Regenerative feature with independent metering circuit.
22 Chapter 22Figure 22.1 Example of typical open center steering system for on‐highway ap...Figure 22.2 Detailed view of the power steering actuator.Figure 22.3 Cross‐section (X‐X) of the hydraulic servo system controlling th...Figure 22.4 Cross‐section of the spool and sleeve in neutral position.Figure 22.5 Operational diagram of a hydrostatic linear steering unit.Figure 22.6 Equivalent schematic of an open center rotary steering unit.Figure 22.7 Simplified cross‐section of a hydrostatic steering unit.Figure 22.8 Hydrostatic steering unit in the operating position.Figure 22.9 Different types of hydrostatic steering units.Figure 22.10 Reactive and nonreactive steering units.Figure 22.11 Priority circuit for fixed displacement pump flow supply.Figure 22.12 Operating modes of the priority valve.Figure 22.13 Cross‐section of constant flow priority valve.Figure 22.14 Priority valve for LS circuit.Figure 22.15 LS priority valve cartridge style architecture.
23 Chapter 23Figure 23.1 Conceptual schematic for hydrostatic transmissions and hydrostat...Figure 23.2 Four quadrant operation for an HT or HA: closed circuit configur...Figure 23.3 Different methods for implementing primary flow regulation: (a) ...Figure 23.4 Different methods for implementing reversal of flow direction in...Figure 23.5 Over‐center variable displacement pump/motor: relationship betwe...Figure 23.6 Classification and nomenclature of the different types of primar...
24 Chapter 24Figure 24.1 Parameters describing a generic hydrostatic transmission.Figure 24.2 HT with variable displacement primary unit and fixed displacemen...Figure 24.3 Transmission ratios (a), torque and power (b) for a PVMF transmi...Figure 24.4 Torque, power, and efficiency curves for a PVMF transmission wit...Figure 24.5 HT with fixed displacement primary unit and variable displacemen...Figure 24.6 Transmission ratios (a), torque and power (b) for a PFMV transmi...Figure 24.7 HT with variable displacement primary unit and variable displace...Figure 24.8 Control strategy for PVMV transmission.Figure 24.9 Transmission ratios (a), torque and power (b) for a PVMV transmi...Figure 24.10 Characteristic diagram for a PVMV transmission considering real...Figure 24.11 HT with variable displacement pump and dual displacement motor ...Figure 24.12 Ratios for a PVM2 hydrostatic transmission.Figure 24.13 Basic schematic of an open circuit hydrostatic transmission.Figure 24.14 Operating modes for the basic circuit in Figure 24.13.Figure 24.15 Typical schematic of an open circuit hydrostatic transmission: ...Figure 24.16 Displacement regulator for open circuit piston pumps with inter...Figure 24.17 Displacement regulator for open circuit pumps with electric fee...Figure 24.18 Typical circuit for a hydrostatic fan drive based on a pressure...Figure 24.19 Quadratic relationship between fan speed and torque. The pressu...Figure 24.20 Engine and fan power considerations for mechanical and hydrauli...Figure 24.21 Conceptual representation of a closed circuit HT.Figure 24.22 Detailed schematic of a closed circuit HT.Figure 24.23 Case drain flows lost in a closed circuit.Figure 24.24 Charge circuit in a closed circuit HT.Figure 24.25 Charge pump circuit inclusive of filtration (Z1).Figure 24.26 Cross‐port relief valves (RV2 and RV3) in a closed circuit HT....Figure 24.27 Solution with integrated cross‐port relief valves and charge pu...Figure 24.28 Closed circuit HT inclusive of the flushing circuit and filtrat...Figure 24.29 Flushing valve symbol.Figure 24.30 The flushing flow can be used to cool the motor housing.Figure 24.31 Displacement regulator for a closed circuit primary unit based ...Figure 24.32 Conceptual schematic of the automotive control.Figure 24.33 Displacement (a) and flow rate (b) of the main pump vs. engine ...Figure 24.34 Implementation of automotive control in a closed circuit pump....Figure 24.35 Example of electrohydraulic displacement regulator for motors....Figure 24.36 Example of automatic pressure regulator for motors.Figure 24.37 Displacement vs. pressure chart for an automatic pressure regul...
25 Chapter 25Figure 25.1 A transmission is the intermediate system between the engine and...Figure 25.2 Hypothetical direct connection between the combustion engine and...Figure 25.3 Four gears can be used to approximate the ideal traction curve....Figure 25.4 Combining an engine with a transmission with a variable ratio.Figure 25.5 Hydrostatic transmission used for propulsion.Figure 25.6 Technologies for variable ratio transmission systems.Figure 25.7 Schematic representation of an automatic transmission.Figure 25.8 Schematic representation of a torque converter and realistic tra...Figure 25.9 Generic schematics for power‐split transmissions. (a) Input‐coup...Figure 25.10 Planetary gear train (PGT): elements and symbolic representatio...Figure 25.11 Linear dependence between the angular velocities of the element...Figure 25.12 Power split obtained with a PGT.Figure 25.13 PGT operation as power summation or power splitting.Figure 25.14 Hydromechanical power‐split transmissions. (a) Output‐coupled. ...Figure 25.15 Detailed schematic for an output‐coupled hydromechanical power‐...Figure 25.16 Simplified schematic for an output‐coupled hydromechanical powe...Figure 25.17 Sequential control of the primary and secondary units for an ou...Figure 25.18 Behavior of the output‐coupled hydromechanical power‐split tran...Figure 25.19 Behavior of the output‐coupled hydromechanical power‐split tran...Figure 25.20 Behavior of the output‐coupled hydromechanical power‐split tran...Figure 25.21 Behavior of the output‐coupled hydromechanical power‐split tran...Figure 25.22 Summary of the operation modes for an output‐coupled hydromecha...Figure 25.23 Qualitative transmission efficiencies for an HT and for an outp...Figure 25.24 Simplifiedschematic for an input‐coupled hydromechanical power‐...Figure 25.25 Sequential control for the HT for an input‐coupled power‐split ...Figure 25.26 Behavior of the input‐coupled hydromechanical power‐split trans...Figure 25.27 Behavior of the input‐coupled hydromechanical power‐split trans...Figure 25.28 Behavior of the input‐coupled hydromechanical power‐split trans...Figure 25.29 Behavior of the input‐coupled hydromechanical power‐split trans...Figure 25.30 Summary of the operation modes for an input‐coupled hydromechan...Figure 25.31 Qualitative transmission efficiencies for both input‐coupled an...Figure 25.32 Series hybrid vehicle. 1 and 2 indicate energy converters.Figure 25.33 Series hydraulic hybrid (simplified schematic).Figure 25.34 Series hydraulic hybrid (realistic circuit).Figure 25.35 Parallel hybrid vehicle.Figure 25.36 Parallel hydraulic hybrid (simplified schematic).Figure 25.37 Parallel hydraulic hybrid (realistic schematic).Figure 25.38 Simplified schematic of the Ford hydraulic launch assist system...Figure 25.39 Series‐parallel hybrid vehicle.Figure 25.40 Hydraulic power‐split hybrid system (output coupled).Figure 25.41 Force balance on the vehicle for calculating the tractive effor...Figure 25.42 HT corner power and prime move power.
26 Chapter 26Figure 26.1 Open circuit hydrostatic actuator using counterbalance valves.Figure 26.2 HA circuit with single acting cylinder.Figure 26.3 Primary control of a differential cylinder in closed circuit.Figure 26.4 System behavior for the case of cylinder extension with resistiv...Figure 26.5 System behavior for the case of cylinder extension with low resi...Figure 26.6 System pressures for the case of cylinder extension.Figure 26.7 System behavior for the case of cylinder retraction with assisti...Figure 26.8 System behavior for the case of cylinder retraction with resisti...Figure 26.9 System pressures for the case of cylinder retraction.Figure 26.10 Summary of the operating conditions for the hydrostatic actuato...Figure 26.11 Closed
