A brake fluid pressure sensor senses the
brake fluid
Brake fluid is a type of hydraulic fluid used in hydraulic brake and hydraulic clutch applications in automobiles, motorcycles, light trucks, and some bicycles. It is used to transfer force into pressure, and to amplify braking force. It works ...
pressure in a
hydraulic
Hydraulics (from Greek: Υδραυλική) is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counter ...
braking system
A brake is a mechanical device that inhibits motion by absorbing energy from a moving system. It is used for slowing or stopping a moving vehicle, wheel, axle, or to prevent its motion, most often accomplished by means of friction.
Background ...
. The
sensor
A sensor is a device that produces an output signal for the purpose of sensing a physical phenomenon.
In the broadest definition, a sensor is a device, module, machine, or subsystem that detects events or changes in its environment and sends ...
is a type of
pressure switch
A pressure switch is a form of switch that operates an electrical contact when a certain set fluid pressure has been reached on its input. The switch may be designed to make contact either on pressure rise or on pressure fall. Pressure switches ar ...
that shows and alerts a fault in the braking system.
Brake problems
The fault could be lack of
hydraulic fluid
A hydraulic fluid or hydraulic liquid is the medium by which power is transferred in hydraulic machinery. Common hydraulic fluids are based on mineral oil or water. Examples of equipment that might use hydraulic fluids are excavators and backhoe ...
, low
brake fluid
Brake fluid is a type of hydraulic fluid used in hydraulic brake and hydraulic clutch applications in automobiles, motorcycles, light trucks, and some bicycles. It is used to transfer force into pressure, and to amplify braking force. It works ...
in the reservoir, a broken hydraulic line or a bad
master brake cylinder. The sensor is used to detect pressure differentials in the hydraulic system. If the car alerts a fault in the hydraulic system and the system checks out, the sensor itself may have failed.
Design
The sensor has an input port to measure the hydraulic braking pressure and an
electrical connector
Components of an electrical circuit are electrically connected if an electric current can run between them through an electrical conductor. An electrical connector is an electromechanical device used to create an electrical connection between ...
output for a
wire
Overhead power cabling. The conductor consists of seven strands of steel (centre, high tensile strength), surrounded by four outer layers of aluminium (high conductivity). Sample diameter 40 mm
A wire is a flexible strand of metal.
Wire is c ...
connection for feeding the
warning light. Some brake failures do not trip the sensor into a fault mode.
A brake fluid pressure sensor is used in
anti-lock braking system
An anti-lock braking system (ABS) is a safety anti-skid braking system used on aircraft and on land vehicles, such as cars, motorcycles, trucks, and buses. ABS operates by preventing the wheels from locking up during braking, thereby maintaini ...
(ABS). ABS fault lights come on with unexpected wheel lock from the ABS system, but could also include low fluid in the reservoir.
New
accident avoidance technologies system also use brake fluid pressure sensors.
DEVELOPMENT OF THE NISSAN ASV-2, Shinji Matsumoto, Toru Yasuda Takeshi Kimura, Taku Takahama, Hiromitsu Toyota, Nissan Motor Co., Ltd.,Japan,Paper Number: 382, accident avoidance technologies
/ref>
Many large heavy vehicles, like truck
A truck or lorry is a motor vehicle designed to transport cargo, carry specialized payloads, or perform other utilitarian work. Trucks vary greatly in size, power, and configuration, but the vast majority feature body-on-frame construction ...
s, particularly those having multiple trailers use air brakes that use air pressure sensors.
Examples
File:DS 4c.tif, Mechanical Pressure Switch with integrated connector
File:Mechanischer Druckschalter mit Steckverbindung.jpg, Mechanical Pressure Switch with Plug-in connector
See also
* Hydropneumatic
Hydropneumatic suspension is a type of motor vehicle suspension system, designed by Paul Magès, invented by Citroën, and fitted to Citroën cars, as well as being used under licence by other car manufacturers, notably Rolls-Royce ( Silver Shado ...
* Pascal's law
Pascal's law (also Pascal's principle or the principle of transmission of fluid-pressure) is a principle in fluid mechanics given by Blaise Pascal that states that a pressure change at any point in a confined incompressible fluid is transmitted ...
References
{{Powertrain
Vehicle braking technologies