*Hydraulic System Simulation Block Library*

This simulation tool is based on the *MATLAB/Simulink* platform, therefore it comes with the familiar *Simulink* graphical user interface for the assembly of system models from already available and verified library blocks. Each block typically represents a hydraulic system component, and each block typically has a piece of computer code associated with it (code developed at *TSC*). With this tool, simulation models of generic hydraulic systems can be built quickly and efficiently. The basic numerical formulation is a one-dimensional finite volume modeling, meaning that length-wise distribution of flow properties is modeled for components in which such variation exists. Therefore, pressure wave dynamics in the hydraulic lines are accounted for. The energy equation is not incorporated, therefore temperature is not calculated in the blocks. However, temperature can be set for each individual block to account for property variations across the system due to temperature variations. The pressure of the working fluid is looked up from the density and the temperature, using detailed property tables. The onset of cavitation and the size of the cavitation bubble can be predicted. Hydraulic system components that can be modeled include hydraulic lines, volumes, orifices, actuators, dampers, accumulators, etc. Blocks for simulating the effects of annular sleeve or other leakages, various pressure losses, and squeeze film damping are also available. A detailed one-dimensional mechanical subset of the block library ensures that complex hydro-mechanical systems like diesel fuel injectors can be accurately modeled. To that goal, the compression of the mechanical parts (important in high pressure diesel injectors) and the bouncing of the mechanical parts on each other after collisions are also accounted for. Finally, magnetic forces in electromagnetic control valves can be modeled in detail using lookup tables for magnetic force and inductance, which tables are determined with finite element analysis of the magnetic circuit.

Examples of components/systems whose design and development can be supported with the *Hydraulic System Simulation Block Library*

1. High pressure diesel injection system such as common rail or hydraulically intensified injection systems

2. Gasoline injection systems

3. Hydraulic valve actuation systems for internal combustion engines

4. Hydraulic hybrid engine systems

5. Engine lube and cooling systems

6. Hydraulic control valves and servo valves

7. Hydraulic brake systems