Valves and Orifices

An in-line multi-element diesel injection system. It consists of a cam shaft, a lift pump, four in-line injection pumps, and four injectors.

A pressure-compensated 3-way flow control valve. This valve maintains constant flow rate through the main hydraulic motor, which is connected to the pressure-compensated outlet of the flow control valve. It acts as a priority valve, diverting the excess flow to the auxiliary hydraulic motor if the main hydraulic motor receives enough fluid to maintain a preset angular velocity. The auxiliary motor is shut off completely if there is insufficient flow to power the main hydraulic motor.

A flow rectifier circuit with four check valves and a flow control valve. It is used to allow a single flow control valve to control fluid flow in both directions. Similar to a Graetz circuit implemented with diodes, the check valves are arranged in such a way that flow always passes through the flow control valve in the same direction. In the Orifices subsystem, there are two more check valves that are used to select the orifice that the flow passes through depending on the flow direction.

Parameterize and test a 4-way 3-position valve with a test harness. A plot script is provided with the example for comparing output flow between the block and data to verify the test harness. A live script is also provided with this example to explain the parameterization and the test harness workflow in detail.

A simplified version of a lubrication system fed with the centrifugal pump. The system consists of five major units: Pump Unit, Scavenge Unit, Heat Exchanger Manifold, Nozzle Manifold, and Control Unit. Both the pump and the scavenge unit are built around the centrifugal pump. The Scavenge Unit collects fluid discharged by nozzles and pumps it back into the reservoir of the Pump Unit. The Control Unit generates commands to bypass either the heat exchanger, represented as a local resistance, or the nozzles block. In a real system, these commands are generated by temperature sensors installed in lubrication cavities.

Model, parameterize, and test a hydrostatic continuously variable transmission (CVT) with a swash angle shift command. When you run the plot function, it generates a comparison plot between the engine and the achieved rotational velocity in the hydraulic axial piston motor with respect to the time. Construction and agricultural equipment manufacturers use these transmissions.

A simplified version of a power-assisted steering mechanism. The hydraulic actuation system includes a double-acting hydraulic cylinder, 4-way valve, fixed-displacement pump, and a pressure-relief valve. The steering rack acts against a load modeled by a spring and damper.

Model, parameterize, and test a pressure control servo valve with a closed loop control. This example also generates a comparison plot between the commanded and the achieved pressure in the actuator with respect to the time. This valve provides a precise and fast control of the pressure in the actuator with a very small electrical signal to the torque motor. These valves are used in the aerospace industry and the automotive industry for the safety critical applications.

Model, parameterize, and test a pressure intensifier.

Model, parameterize, and test a hydraulic clutch system. The model is used to generate the plot of the engine and the transmission system speeds during a declutching and clutch re-engaging scenario.

Model, parameterize, and test a pressure control solenoid valve. This example also generates a plot of the relationship between applied solenoid force and the resulting actuator port pressure.

An actuator controlled by a 4-way directional valve and loaded with an overriding load, requiring the use of counterbalance valves to prevent the load from creeping when the directional valve is in the neutral position. In the neutral position, the directional valve connects ports A and B to the reservoir while blocking the pressure port P. The counterbalance valves block flow from returning to the reservoir, thus holding the actuator in place.

A flow rectifier circuit with four check valves and a flow control valve. It is used to allow a single flow control valve to control fluid flow in both directions. Similar to a Graetz circuit implemented with diodes, the check valves are arranged in such a way that flow always passes through the flow control valve in the same direction. In the Orifices subsystem, there are two more check valves that are used to select the orifice that the flow passes through depending on the flow direction.

A simplified version of an actuation system consisting of the lift and tilt cylinders. Each cylinder is controlled by an open center, 6-way, 3-position directional valve. The valves are connected in series through their unloading branch such that the system pump is unloaded when both command levers are in neutral position. If either tilt or lift command is applied, the unloading path is closed.

A test rig designed to investigate the interaction between an axial-piston pump and a typical control unit simultaneously performing the load-sensing and pressure-limiting functions. To increase the fidelity of the simulation, this example uses a detailed model of the pump that accounts for the interaction between the pistons, swash plate, and valve plate.

An actuator that drives a machine tool working unit performing a sequence of three technological operations: coarse drilling, fine drilling, and reaming. The actuator speed is controlled by one of three pressure-compensated flow control valves metering out return flow from the cylinder. The selection of an appropriate flow control is performed by directional valves that are activated by a control unit.

Models a hydraulic system with a direct operated, pressure reducing valve. This system helps to limit and maintain pressure in a hydraulic punching machine. Pressure reducing valves are common in hydraulic pressing, drilling, and stamping applications.

Compares the mechanical performance of various spool actuation configurations and model fidelity levels for a hydraulic 4-way 3-position directional valve. The directional valve controls a simple double-acting cylinder in a closed-loop application. This example allows you to choose among four different spool actuation designs: abstract actuator,

A simple way of modeling of the anti-lock braking system (ABS) and using it with the manual braking components. The model simulates for the open loop ABS and shows the response of the pressures achieved in the caliper disc brakes. This model can be utilized in sizing of the release valve, apply valve and accumulator for the hydraulic control unit of the ABS.

A simple way of modeling an ABS braking system. The model shows the velocity profile responses achieved for the vehicle CG and the wheels.