BGMod Documentation / v3
BGMod handbook

4/3 directional valve

Advanced component · equations, parameters and limits.

Valve43 — proportional 4/3 valve

Hydraulic power ports P/T/A/B; dimensionless signal input u in −1…1. Connect an external source from Dimensionless Signal.

G_PA = G_BT = max(u, 0) G_open
G_PB = G_AT = max(−u, 0) G_open
Qij = Gij (pi − pj); P_loss = Σ Gij (pi − pj)² ≥ 0

G_open > 0, default 10⁻¹¹ m³/(Pa·s). u = +1 extends, u = −1 retracts, u = 0 closes every passage. Intermediate magnitude scales conductance. Closed flow is exactly zero; open flow may reverse.

No spool dynamics, leakage or quadratic orifice law. Closing passages does not instantly stop a moving mass. Outputs include command and dissipation. The proportional example retains the existing cylinder circuit without adding MR.

Signal sources, schedules and v1/v2 migration

Classic bond graph

Classic bond graphFour common-pressure 0-junctions P, A, B, T joined by four paths PA, PB, BT, AT. Each path contains a series 1-junction with a one-port modulated resistance.0P0A0B0T1MR : PA1MR : BT1MR : PB1MR : ATG_PA = G_BT = max(u, 0) G_openG_PB = G_AT = max(−u, 0) G_open
Classic expansion of the four implemented resistive passages. Each passage is 1 + one-port MR; the four 0-junctions collect flows at the named pressure ports. The software’s internal view abbreviates each entire passage as an MR edge; that edge is not the standalone one-power-port MR block. Here each MR obeys Qij = Gij e_MR and e_MR = pi − pj. All four conductances use the same non-power input u as shown below the graph; u = 0 sets all flows to zero. No fluid storage is added by these junctions. Half-arrows set positive power references; dashed pink arrows carry signals only. Causal strokes are omitted because they depend on the connected model.