The Total braking force acting at front wheels (when brakes are applied to front wheels only) formula is defined as the measure of braking power of...
The Total braking force acting at front wheels (when brakes are applied to front wheels only) formula is defined as the measure of braking power of...
In this formula, Braking force uses Mass of vehicle, Retardation of vehicle, Acceleration Due To Gravity & Angle of inclination of plane to horizon...
This means that, when force is applied to this fluid, it can’t become denser. Instead, it has to move from one place to another. In the case of brakes, this fluid is a special kind of oil that won’t boil at high temperatures or thicken at low ones.
As a result, your braking system needs to multiply the force that you put into the system, so that a greater force will be produced at the braking device. This is accomplished through the application of leverage and hydraulic force multiplication .
In this system, the distance from brake pedal to the pivot is four times the distance from the piston head to the pivot. (Note that both “outputs” can be on the same side of the pivot, which allows you to have your input and output forces going in the same direction.) This increases the input force by a factor of four.
In a car’s braking system, the lever attached to the brake pedal multiplies the force produced by your foot before transmitting this force to the hydraulic system, where the force undergoes further multiplication. A hydraulic system, such as the one that powers your brakes, uses an incompressible fluid.
In a hydraulic system, pressurized fluid passes through tubes, cylinders, and the like to transmit force from one place (the pedal) to another (the brake device.) Cars use different kinds of brakes: drum, disc, and power brakes. Many cars use a combination of brakes, with drum brakes on the rear wheels and disc brakes on the front.
Essentially, the hydraulics in your brakes work a bit like a giant syringe: when you apply pressure to a piston at one end, the fluid transmits the same pressure to a piston at the other end. (See Figure 3)
However, braking systems are elegant, ingenious, and complicated systems. With the help of a few basic principles of physics, the smallest exertion on your part can be magnified into enough force to stop a car. Like so many systems in your car, your brakes run on a hydraulic system. In a hydraulic system, pressurized fluid passes through tubes, ...
Seventy pounds of force on a brake pedal can result in 556 psi of brake fluid heading to the calipers. So how does this pressure stop a car?
To keep things simple, let’s return to our manual brake example. The rod coming from the firewall has 434 pounds of output force. When the force is applied to the back of the master cylinder, the force is transferred into the brake fluid.
Pedal ratio is the overall pedal length or distance from the pedal pivot to the center of the pedal pad, divided by the distance from to the pivot point to where the push rod connects.
A lower ratio can give shortened pedal travel and better modulation. Most vacuum-boosted vehicles will have a 3.2:1 to 4:1 mechanical pedal ratio.
A lower ratio can give shortened pedal travel and better modulation. Most vacuum-boosted vehicles will have a 3.2:1 to 4:1 mechanical pedal ratio. The size of the booster’s diaphragm and amount of vacuum generated by the engine will determine how much force can be generated.
Let’s start with the driver. In a sitting position, the average driver can comfortably generate 70 pounds of force on the rubber pad at the end of the brake pedal. The brake pedal is nothing more than a mechanical lever that amplifies the force of the driver. This is where the pedal ratio comes into play.
Most engines will generate around -8 psi of vacuum (do not confuse with inches of Hg, or mercury). If a hypothetical booster with a 7-inch diaphragm is subjected to -8 psi of engine vacuum, it will produce more than 300 pounds of additional force. Here is the math: