What does the accumulator in a hydraulic brake booster contain to provide back-up pressure?

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Multiple Choice

What does the accumulator in a hydraulic brake booster contain to provide back-up pressure?

The accumulator stores energy as a compressed gas to provide back-up hydraulic pressure. In a hydraulic brake booster, one side of the accumulator holds brake fluid and the other side holds a high-pressure gas—typically nitrogen—separated by a diaphragm or piston. This gas charge acts like a springy reservoir: when the brake system needs extra pressure, the gas expands and pushes fluid into the booster, maintaining assist even if the pump momentarily lags. That stored pressure is what gives the system a quick, reliable boost during heavy braking. Other options don’t fit because brake fluid alone can’t store extra energy, a steel rod isn’t a source of pressurized hydraulic energy, and a magnet has no role in supplying hydraulic back-up pressure.

The accumulator stores energy as a compressed gas to provide back-up hydraulic pressure. In a hydraulic brake booster, one side of the accumulator holds brake fluid and the other side holds a high-pressure gas—typically nitrogen—separated by a diaphragm or piston. This gas charge acts like a springy reservoir: when the brake system needs extra pressure, the gas expands and pushes fluid into the booster, maintaining assist even if the pump momentarily lags. That stored pressure is what gives the system a quick, reliable boost during heavy braking.

Other options don’t fit because brake fluid alone can’t store extra energy, a steel rod isn’t a source of pressurized hydraulic energy, and a magnet has no role in supplying hydraulic back-up pressure.

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