Braking Systems (ABS) Flashcards
In an electronic stability control system, what sensor measures the “side to side” twist of the vehicle?
yaw rate sensor
What frequency does a magnetic pulse type wheel speed sensor produce?
varying AC frequency
How often can some antilock brake systems modulate pressure to the brakes?
20x per second
What fluid is recommended for most antilock brake systems?
DOT3
How are the channels of a 1 channel antilock brake system arranged?
none at the front wheels and both rear wheels together as one
How are the channels of a 3 channel antilock brake system arranged?
right front wheel, left front wheel and both rear wheels together
How are the channels of a 4 channel antilock brake system arranged?
at each of the 4 wheel separately
What is the gas filled pressure chamber that is part of the antilock braking system’s pump and motor assembly?
Accumulator
What occurs when the automatic traction control system is operating?
The brakes will be modulated on the spinning drive wheel
What must be performed before removing a high pressure accumulator equipped cylinder on an ABS equipped vehicle?
Pump the brake pedal 25-50 times with the key off
What tool should be used to measure a wheel speed sensor gap?
brass feeler gauge
Define an automatic traction control system.
Applies the brakes of a drive wheel when it attempts to spin and lose traction
Define an automatic stability control system.
Correct oversteer and understeer by applying one-wheel brake to bring the vehicle back under control
Define an integrated antilock braking system.
Combines all of the components necessary to provide conventional hydraulic brakes, power assist, and antilock control into one assembly
Define an nonintegrated antilock braking system.
The functions of conventional braking and power assist are provided by the conventional power brake components, while the function of antilock control is provided by the ABS
What are the proper steps and testing needed to accurately diagnose antilock braking systems?
1) pre-diagnostic inspections & test drive
2) warning light & symptom troubleshooting
3) on-board self-diagnostics & code retrieval
4) individual component testing & trouble-code-based troubleshooting
What is the formula for Slip Ratio?
(vehicle speed - wheel speed) / vehicle speed x 100%
What are the 4 main components of an ABS system?
- Wheel speed sensors
- Valves/modulator
- Pumps
- Computer/controller
What are 6 main control methods for ABS systems?
- Classic Control
- Optimal Control
- Nonlinear Control
- Robust Control
- Adaptive Control
- Intelligent Control
What does 0% to100% range for slip ratio mean?
0% vehicle speed and 100% completely locked
According to slip ratio, when does the best braking occur?
10% - 20%
What is the main benefit from ABS?
maintain steering ability while slowing down the vehicle
What is a Nonintegrated ABS system?
Master cylinder and control valve assembly are separate
What is an Integrated ABS system?
Master cylinder and control valve assembly are made together
Statistically, what percentage of accidents are due to skidding?
40%
