This simulator traces oil from a motor-driven power pack through a 4/3 directional valve into a cutaway tie-rod hydraulic cylinder. Adjust piston bore, rod diameter, stroke length, relief pressure setting, pump delivery, opposing load, seal friction and return pressure, then compare extension and retraction speed, load stalls and relief bypass in real time.
• A real-time 3D cutaway workbench of the tie-rod cylinder and working chambers, piston/rod/seal/load carriage, oil reservoir and motor-pump power pack, 4/3 directional spool valve, adjustable relief branch, return filter and lines, and a guided load/stroke reference fixture, with home view, focus-selected-part, show-full-enclosure, exploded view, auto-rotate, expand and show/hide labels controls. • Four action controls: extend cylinder, retract cylinder, center valve/block ports, and isolate supply/vent chambers. • Playback controls: pause/resume, 0.1 s and 1 s step advances, and five playback speeds (10× and 100× slow motion, real time, 10× faster, one minute per second). • A Curves & measurements tab with a live cap/rod chamber pressure comparison chart, a motion-and-energy history chart, the full model equations (areas, pressure force, extend/retract velocity, relief conditions, relief power) and snapshot measurement readouts covering position, velocity, chamber pressures, net force, effective areas, theoretical push/pull capacity, port flows, relief flow and supply power. • An Experiments tab with four guided fixtures (nominal extension, compare retraction, stall against excess load, raise return pressure) and a Model verification bench that runs independent deterministic checks against a fresh model without disturbing your live trial, plus a timestamped event log and a copyable trial report. • A Learn & assess tab with guided lessons, a knowledge-check quiz with reset, and a written model-scope statement with a technical reference link.
A hydraulic cylinder converts pump flow and pressure into linear force and motion. Force comes from pressure acting across the piston's effective area — the full bore area on the cap side, but only the smaller rod-side annulus (bore area minus rod area) on the retract side, since the rod itself occupies part of that chamber.
Because the annulus is smaller than the full piston area, retraction is faster than extension at the same pump flow, even though it produces less force. Travel speed is simply flow divided by the active area — doubling the pump's ideal delivery doubles travel speed at a fixed area.
This is a constant-flow-pump circuit: the pump does not force its maximum pressure at every instant. Pressure rises only as far as needed to overcome the opposing load, seal friction and return-side backpressure — until it reaches the relief valve's set pressure. At that point, or when the piston reaches its stroke stop, motion stops and the pump's full delivery bypasses through the relief branch, converting to heat (relief power = relief pressure × bypass flow).
The model is quasi-steady incompressible oil with an ideal constant-flow pump — it does not include acceleration, cavitation, internal leakage, pressure losses beyond the specified return pressure, relief-valve dynamics or a temperature solution, and the blocked-center hold assumes ideal trapped oil with no drift. Component geometry and flow-direction markers are representative and illustrative rather than a validated manufacturer design.
Retraction acts on the rod-side annulus, which is smaller than the full piston (cap-side) area because the rod occupies part of that chamber. Since travel speed equals flow divided by active area, the smaller annulus means retraction moves faster — but with less force capacity — than extension at the same delivered flow.
With a constant-flow pump and blocked motion, cylinder pressure rises until it reaches the relief valve's set pressure. From that point, the pump's entire delivery bypasses through the relief branch back to tank rather than continuing to build pressure, and that bypass flow becomes a calculated heat rate.
The simulator models a blocked-center hold as ideal trapped oil with no drift, which is a simplification. It does not model real leakage paths, thermal expansion or valve spool tolerances that could allow slow drift in an actual circuit.
No. It is a quasi-steady, incompressible-oil teaching model with idealized constant-flow supply — it omits pressure losses, cavitation, internal leakage, relief-valve dynamics and thermal effects. A proper hydraulic circuit design requires manufacturer catalog data and a full engineering analysis.