Subtopic: I.C. engine systems – fuel, cooling, lubrication, ignition, electrical, intake and exhaust
Question Statement:
A double acting hydraulic cylinder has a bore of 200 mm with a piston rod of 140 mm diameter. The extend speed of the piston is 80 mm s⁻¹. If the flow rate of oil during retraction is same as that of the extending, the retract speed of the piston in mm s⁻¹ is _____.
Official Answer Key:
156.5 to 157.5
Step-by-Step Solution & Explanation
During extension, the full piston area receives flow: A_full = (π/4)(0.2)² = 0.031416 m².
Flow rate Q = A_full × V_extend = 0.031416 × 0.08 = 2.513×10⁻³ m³/s.
During retraction, flow enters the annular (rod) side: A_annular = (π/4)(0.2²−0.14²) = (π/4)(0.0204) = 0.016022 m².
Retract speed V_retract = Q/A_annular = 2.513×10⁻³/0.016022 = 0.1569 m/s = 156.9 mm/s. This lies within the accepted range 156.5–157.5.
Section 4 — Soil and Water Conservation Engineering
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