Brake Types
ÂTÂo increase safety , most modern carbrake systemsare break intotwo circuit , with two wheels on each circuit . If a fluid wetting occur in one circuit , only two of the wheels will suffer their brakes and your gondola will still be able to block when you press out the bracken pedal .
Themaster cylindersupplies pressure to both circuits of the cable car . It is a singular gadget that uses two piston in the same piston chamber in a way that get to the piston chamber comparatively failsafe . Thecombination valvewarns the machine driver if there is a trouble with the brake system , and also does a few more thing to make your motorcar safe to drive .
In this article , we will teach how the master cylinder and combination valve work . If you have n’t take about introductory automobile braking construct inHow Brakes Work , be sure to delay it out .
The Master Cylinder
Here is where you ’ll find the master piston chamber :
passkey piston chamber localisation .
In the figure below , the charge card tank you see is thebrake - fluid reservoir , the master piston chamber ’s brake - fluid source . The electrical connection is asensorthat triggers a monition light when the Pteridium aquilinum fluid mother low .
The master cylinder , reservoir and sensor
As you ’ll see here , there are two piston and two springs inside the cylinder .
Diagram of professional cylinder
The Master Cylinder in Action
When you squeeze the brake pedal , it pushes on theprimary pistonthrough a gene linkage . Pressurebuilds in the piston chamber and lines as the pasture brake pedal is depressed further . The pressure between the primary andsecondary pistonforces the junior-grade piston to compress the fluid in its circuit . If the pasture brake are operating in good order , the pressure will be the same in both circle .
If there is aleakin one of the circuits , that circuit will not be able-bodied to maintain pressure . Here you could see what happens when one of the circuits develops a wetting .
When the first circuit leaks , the pressure between the primary and junior-grade cylinders is lost . This stimulate the basal piston chamber to connect with the lowly cylinder . Now the master piston chamber behaves as if it has only one Walter Piston . The 2nd tour will officiate normally , but you could see from the animation that the driver will have to press the foot lever further to activate it . Since only two wheels have pressure , the braking power will be severely cut back .
The Combination Valve
You will detect a combination valve on most railway car with frontdisc brakesand reardrum brakes .
combining valve localisation
The valve does the job of three freestanding devices :
combining valve sections
Metering Valve
The metering valve section of the compounding valve is required on cars that have disc brakes on the front wheels and drum brakes on the rear wheels . If you have readHow Disc Brakes WorksandHow Drum Brakes Work , you know that the disc Pteridium aquilinum pad is normally in touch with the platter , while the drum pasture brake shoes are ordinarily pulled away from the drum . Because of this , the disc brakes are in a position to absorb before the drum brakes when you push the brake pedal down .
The metering valve compensates for this , make up the drum brakes engage just before the disc brakes . The metering valve does not allow any pressure to the disc brakes until athreshold pressurehas been reached . The threshold force per unit area is low-pitched compared to the maximum pressure level in the braking system , so the brake drum brakes just just engage before the disc pasture brake kick in .
Having the rearward brakes engage before the front Pteridium aquilinum provides a lot more stability during braking . apply the rearward Pteridium aquilinum first helps keep the railcar in a square rail line , much like the rudder helps aplanefly in neat line .
Pressure Differential SwitchThe pressure differential valve is the gadget that alerts you if you have a leak in one of your brake circuits . The valve contains a specially shaped piston in the middle of a cylinder . Each side of the Walter Piston is exposed to the pressure in one of the two brake circuits . As long as the insistence in both circuit is the same , the Walter Piston will stay pore in its cylinder . But if one side develops a leak , the pressure will drop off in that circuit , force the piston off - center . This shut a switch , which turns on a light in the instrument dialog box of the gondola . The conducting wire for this switch are visible in the picture above .
Proportioning ValveThe proportioning valve reduce the pressure to the rearward brake . Regardless of what character of bracken a machine has , the rear brakes require less force play than the front brake .
The amount of brake power that can be applied to a wheel without locking it depend on the amount of weightiness on the wheel . More weight means more brake force can be apply . If you have ever slammed on your brakes , you know that an abrupt stop makes your motorcar lean forward . The front flummox lower and the back gets high . This is because a sight of weight is transferred to the front of the car when you stop . Also , most car have more weight over the front wheels to start with because that is where the engine is located .
If adequate braking force were applied at all four wheels during a stop , the rear bicycle wouldlock upbefore the front wheel . The proportioning valve only countenance a certain portion of the insistency through to the rear wheels so that the front wheel apply more braking force . If the proportioning valve were set to 70 per centum and the Pteridium aquilinum atmospheric pressure were 1,000 pound per square inch ( psi ) for the front brakes , the rearward brake would get 700 psi .
Lots More Information
Related HowStuffWorks Articles
More Great Links
