• Open Center Systems 开芯式系统
– Main system 主要系统 – Pilot system 先导系统 – Implement valve function 工作阀功能 – Area curves 面积曲线 – Performance Characteristics 性能特性 – Math Modeling 数学建模 – Problems/Exercises 问题/练习
通过测量对SEM650的计算进行验证
• Specific objectives 特定目标
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Wheel Loader Power Flow
Fan, Alternator, Air Cleaner, Muffler (MEC, LEC) T = f (Engine Speed)
Brake pump, Pilot pump, Steering pump, Transmission pump (H&HS) T = Disp * Pressure/ Efficiency
• Caterpillar – most Cat engineers call this an open center valve
• Industry & Academia – open center valve
– In neutral – Pump to cylinder to tank all open
Hydraulic Schematics
Main Flow Lines Pilot Lines Pump
Gross Engine Lug Curve MEC & LEC
Rimpull
Torque Converter
Torque Ratio Primary Torque (ft-lb)
3.50 3.00 2.50 2.00 1.50 1.00 0.50 0.00
0.000
0.200
E4611 AAA IL Torque Converter Data
0.400
0.600 Speed Ratio
0.800
1.000
1400.0 1200.0 1000.0 800.0 600.0 400.0 200.0 0.0 1.200
Torque Ratio Primary Torque (ft-lb)
Converter Data TBU
F
y
F
x
Implement Pump H&HS
Tilt Force/Speed翻转力/速度
Steering Force Speed 转向力/速度
Brake Charging Pump 刹车辅助泵
Brake Force 刹车力
Implement Pilot Pump 工作先导泵
Transmission Pilot Pump 变速箱先导泵 Air Cleaner, Muffler, Alternator 空滤器，消音器，发电机
Implement Heat 工作热能
6%
Steering Heat 转向热能
1%
Fan Heat 2%
风扇热能
Pilot Heat 先导热能
Work 10%
2%
Xmsn Pump Heat 2%
变速箱泵热能
Power Train 传动热能
11%
Brake Heat 刹车热能
2%
Eng Stack Heat
• Closed Center Systems 闭芯式系统
– Variable Implement Pump Controls 可变的工作阀 控制
– Load Sensing Circuits 负载敏感回路 – Problems/Exercises 问题/练习
Terminology
• Industry & Academia – tandem center valve – Means that in neutral the flow path from – Pump to Cylinder - closed – Cylinder to Tank - closed – Pump to Tank – open
Hydraulics at Work
Hydraulics at Work
Hydraulics at Work
Hydraulics at Work
Website with video /watch?v=HO-wTO7ice8
Implement System 工作系统
发动机3排8%气热能
Wheel Slip Heat 车轮滑移热能
1%
Alt/AirCln/Muf Heat 空滤器，消音器，发电机热能
1%
Eng Cooled Heat 发动机冷却热能
24%
Focus Primary users of energy
焦点 能量的主要使用者
• Implement System 工作装置系统 • Powertrain System 传动系统
Bucket Force Speed 铲斗力/速度
Energy Distribution during
Truckloading 9XX 9XX 装车应用时的能量分配
9XX Energy Distribution 9XX 能量分配
32 sec Truck Loading Cycle 32 秒钟装车周期
Objectives 目标
• Understand & study 了解及学习
– Hydraulic systems 液压系统
• Open Center mponents 液压零件 • Basic Equations 基本公式 • Calculations • Validate calculation with measurements on
T = Disp * Press / Eff
Fuel 燃油
Power Flow 动力流动
Converter 变矩器
Rimpull 牵引力 Wheel Speed 轮速
Implement Pumps 工作泵
Lift Force/Speed 举升力/速度
Engine 发动机 Heat 热能
Cooling Pump 冷却泵 Steering Pump 转向泵