WATER-COOLED ENGINES

The most common method to cool the engine is to circulate water, in a water jacket, round the cylinders. The water absorbs the heat and carries it away. The heated water is passed through a radiator in which it is cooled before being circulated again over the hot cylinders. The radiator is designed to expose a very large surface area to the air flow, maintained partly by the motion of the car and partly the action of the fan which belt is driven off the engine crankshaft.

The operation of the water-cooling system is controlled by the distance thermometer. The thermostat automatically maintains the required temperature of the engine.

Pressurised systems.

On modern cars the cooling system is " pressurised". The filler cap has a spring loaded valve in it to maintain the pressure in the radiator about 10 pounds per square inch above normal atmospheriс pressure. This increased pressure raises the boiling point of the water and increases the running temperature of the engine slightly. A second valve in the filler cap allows air into the system as the water cools and thus avoids the formation of a partial vacuum.

Задание 1. Изучите рис. 11 и подберите русские эквиваленты терминов, обозначающих элементы двигателя с водяным охлаждением. Проверьте себя по специальному словарю.

1) filler cap; 2) radiator; 3) water pump; 4) fan; 5) drain tap; 6) top hose; 7) thermostat; 8) water jacket; 9) bottom hose; 10) thermometer; 11) sensor; 12) cylinder; 13) oil radiator; 14) curtain.

Задание 2. Догадайтесь о значении следующих словосочетаний, используемых для описания работы двигателя c водяным охлаждением:

to cool the engine; to circulate water; round cylinders; absorb the heat; over the hot cylinders; to expose surface area; the air flow; the pressurised system; boiling point.

Задание 3. Расскажите об устройстве и работе двигателя с водяным охлаждением, дополнив следующие предложения.

1. In the...... engine water... heat.

2. Water circulates in...... round cylinders.

3. The heated water is passed through....

4. The radiator... a very large surface area to the.......

5. The cooled water... again over the hot....

6. … maintains the required temperature of the....

Vocabulary

Узлы и детали двигателя с водяным охлаждением:

water jacket, cylinders, radiator, thermostat, engine.

Глаголы, используемые для описания рабочих процессов в двигателе с водяным охлаждением:

to absorb, to expose, to circulate, to cool.

Рис. 11