Shock absorbers use which kind of gas for better damping?

• A. Helium
• B. Argon
• C. Nitrogen
• D. Oxygen

Answer: (C)

Gas-charged shock absorbers rely on a pressurized gas to separate the hydraulic oil from the piston area, so the gas helps prevent foaming and keeps the damping force stable as the shock moves rapidly. Nitrogen is used because it’s inert, dry, and inexpensive, and it has low solubility in oil. This combination keeps a clean, stable gas layer under pressure, reducing cavitation and maintaining consistent damping across a range of speeds and temperatures.

Helium would leak more easily through seals and isn’t cost-effective. Argon, while inert, isn’t as practical for widespread automotive use. Oxygen would risk oxidation of oil and components and wouldn’t help prevent foaming as effectively as nitrogen.