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10.Read the text and the statements beneath it. Agree or disagree with them. Then answer the questions
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10. Read the text and the statements beneath it. Agree or disagree with them. Then answer the questions
Brakes
Brakes are used to slow or stop the car where it is necessary. It is one of the most important mechanisms of the car as upon its proper performance the safety of passengers depends. Car brakes can be divided into two types, namely: drum brakes and disc brakes. The drum type may be either a band brake or a shoe brake.
Depending on their functions, the automobile has foot brakes and hand brakes (parking brakes). According to their mode of operation, the brakes are classified as: mechanical brakes, hydraulic brakes, air brakes, electric brakes. Brakes are controlled by the brake pedal.
Most braking systems in use today are hydraulic. This system consists of a master cylinder mounted on the car frame and wheel cylinders. When the driver pushes down on the brake pedal, it forces the piston to move in the master cylinder and brake fluid is delivered from it to the wheel cylinders. The piston movement causes brake shoes to move and the brakes are applied (the brake shoes are pressed against the brake drums).
The air brake uses compressed air to apply the braking force to the brake shoes.
Electric brakes use electromagnets to provide the braking effort against the brake shoes.
Formerly brakes were applied only to the two rear wheels, but now all cars are equipped with all-wheels brakes. Today many improvements are being made in brakes.
Agree or disagree
1. Car brakes can be divided into three types, namely: drum brakes, plate brakes and disc brakes.
2. According to their mode of operation, the brakes are classified as: mechanical brakes, hydraulic brakes, water brakes, electric brakes.
3. When the driver pushes down on the brake pedal, it forces the piston to move in the master cylinder and brake fluid is delivered from it to the gearbox.
4. Electric brakes use electromagnets to provide the braking effort against the brake shoes.
Answer the questions
1. What are brakes used for?
2. What is one of the most important mechanisms of the car responsible for the safety of passengers?
3. What two types can car brakes be divided into?
4. What are brakes controlled by?
5. Most braking systems in use today are hydraulic, aren’t they?
6. Does the air brake use compressed air to apply the braking force to the brake shoes?
7. What do electric brakes use electromagnets for?
11. Read the text. Four sentences are incomplete. Choose the correct endings from A-E to complete each sentence (1-4). There is one extra ending which you do not need to use
Master and Slave Cylinders
A hydraulic brake circuit has fluid-filled master and slave cylinders connected by pipes. The master cylinder transmits hydraulic pressure to the slave cylinder 1________________________.
When you push the brake pedal it depresses a piston in the master cylinder, forcing fluid along the pipe. The fluid travels to slave cylinders at each wheel and fills them, forcing pistons out to apply the brakes. Fluid pressure distributes itself evenly around the system. The combined surface 'pushing' area of all the slave pistons is much greater 2_______________________. Consequently, the master piston has to travel several inches to move the slave pistons the fraction of an inch it takes to apply the brakes. This arrangement allows to apply great force to the brakes, in the same way that a long-handled lever can easily lift a heavy object a short distance.
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Most modern cars are equipped with dual (двойной) hydraulic circuits, with two master cylinders in tandem, in case one should fail.
Sometimes one circuit works the front brakes and one the rear brakes; or each circuit works both front brakes and one of the rear brakes; 3________________________.
Under heavy braking, so much weight may come off the rear wheels that they lock, possibly causing a dangerous skid. For this reason, the rear brakes are deliberately made less powerful 4___________________.
Most cars now also have a load-sensitive pressure-limiting valve. It closes when heavy braking raises hydraulic pressure to a level that might cause the rear brakes to lock, and prevents any further movement of fluid to them.
Advanced cars may even have complex anti-lock systems that sense in various ways how the car is decelerating and whether any wheels are locking. Such systems apply and release the brakes in rapid succession to stop them locking.
A. than the 'pushing' area of the piston in the master cylinder.
B. or one circuit works all four brakes and the other the front ones only.
C. than the front.
D. until the linings come into contact with the inside of the drum and force it to stop.
E. when the pedal is pressed.
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