History of Hydraulics - Part One - Motorsport Tech Sessions |
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Grant Loc
March 20, 2014
Hello, race season has arrived and it is time to get your foot on the gas pedal.....
Today I am starting a two part series on the Hydraulic brake system.
The two parts will be:
Part One: The History of Hydraulics and Brake System Hydraulics Part Two: Hydraulic System Performance and Pedal and Hydraulic Ratios.
Lets get started.
Part One: History of Hydraulics and Brake System Hydraulics
History of Hydraulics: The term Hydraulics comes from two separate Greek words referring to water and pipe. As far back as the 6th century BC, the behavior of water and its flow through pipes has been studied.
The father of modern Hydraulics is French mathematician Blaise Pascal (1623 - 1662). Pascal established Pascal's Law and is the namesake of the SI unit for pressure, the Pascal (Pa).
Pascal's law states 'a change in pressure at any point in an enclosed fluid at rest is transmitted undiminished to all points in the fluid.' In Pascal's 1646 barrel experiment, he fitted the top of a barrel with a long vertical pipe. While this barrel would have no problem containing the pressure of the fluid it would take to fill it, the additional pressure from the weight of the fluid in the tube attached to the barrel would cause it to eventually leak due to the increase in pressure.
Mathematically, Pascal found the amount of pressure resulting from this column of fluid would be a function of the height of the column and the density of the fluid. Later experiments with U-tubes filled with water with varying size pistons and tube diameter's led to the invention of the Hydraulic press.
Brake System Hydraulics: The hydraulic brake system on a vehicle starts at the master cylinder and ends at the calipers. The master cylinder is responsible for establishing the amount of pressure in the brake lines and calipers. A mechanical lever, known as the brake pedal, accepts a mechanical force input from the driver's foot.
The force causes a pushrod to push the piston assembly within the master cylinder. In turn, the master cylinder increases the pressure in the hydraulic brake system. This increase in pressure exerts additional force on the calipers to squeeze the brake pads to the rotors.
Any portion of the brake system that carries the hydraulic brake fluid is part of brakes hydraulic system. This includes master cylinders, hard brake lines, proportional valve, flexible brake lines, pedal box and calipers.
Thank you reading the article.