Exercise 5. Read dialogues and reproduce them then make up your own dialogues based on topics given below.
A.: What are some of the causes of loss of injection air pressure?
В.: Leaky, broken or stuck compressor valves, injection air valve sticking open, leaky spray air valve stem packing, leaky joints in air piping, loss of cooling water.
A.: How can a start be held if there is no compressor available?
В.: Procure a bottle of CO2 gas and connect it to the starting air line. This gas is non-explosive and safe to use for this purpose.
A.: What are some of the causes of failure of an engine to start firing after it begins to turn on air?
В.: Fuel pumps not discharging oil, incorrect timing of fuel valves, low compression, injection air pressure too low and cylinders too cold.
A.: What are some of the causes of cracked cylinder heads?
В.: Unequal heating, due to poor design, air pockets in jacket, insufficient cooling water and overloading.
A.: How does wear on main bearings cause crank shaft to break?
В.: By throwing the shaft out of line and causing it to be bent in alternate directions twice in every revolution.
A.: Give the valve timing for the average and large 4-cycle engine.
В.: Injection valve opens 5 degrees before top center, injection valve closes 49 degrees past top center, exhaust valve opens 140 degrees past top center, air inlet valve opens 15 degrees before top center, exhaust valve closes 10 degrees past top center, and air inlet closes 214 degrees past top center. When in use, the air starting valve opens at top center and closes at 128 degrees past top center.
A.: What is the most important valve timing?
В.: The time of opening of the injection valve. A small change in this time may seriously affect the operation of the engine.
A.: When setting valves how to determine when the injection valve opens?
В.: Keep moving the cam roller with the fingers until it makes contact hard enough to bind, turn injection air into the valve and listen for the hiss of air through the indicator cock when the valve starts to open, or use a micrometer dial indicator to note when the valve stem starts to lift.
Comprehensive reading. Read, translate into Russian and discuss the following text
Burst of pipes
Burst of pipes in the water system is one of the most common plumbing problems both in the home and the public system. Several things can cause burst pipes, the main one is freezing conditions.
The most likely cause of a burst pipes will come from frozen temperatures and unprotected piping. A pipe bursts when frozen due to the expansion of the water as it becomes ice. This puts pressure on the pipe from the inside and something has to give. This almost always is the soft copper or plastic of the pipe. Sometimes these breaks can be at the weaker joints or in the middle of the pipe. As quite a lot of piping is hidden in flooring, roof spaces or walls, the damage caused can be devastating.
|
|
|
If a pipe freezes...1) Turn off the water supply at the stopcock. 2) Check to see if the pipe has burst. 3) Slowly thaw the pipe with hot water bottles or a towel soaked in hot water, starting at the end nearest the tap. 4) You can also use a hair-dryer (lowest setting) but NOT a naked flame or blowlamp.
Remember: don't leave taps dripping or running as the water may not drain down the plughole if the pipe below is frozen.
If a pipe bursts... 1) Turn off the water supply at the stopcock. 2) Open all taps to reduce flooding. 3) Soak up/block off escaping water with thick towels. 4) Call a qualified plumber. 5) Turn off taps once pipework is repaired to avoid further flooding.
Exercise 6. Discuss the following topics:
1) What is the main cause of burst of pipes?
2) Explain why pipes burst when frozen.
3) What kind of material in pipes can’t stand the pressure?
4) Why is the damage so devastating?
5) What is necessary to do when pipes got frozen or burst?
6) What other advice can you give?
Lesson 4. STARTING DIFFICULTIES
Exercise 1. Read and learn the following words and expressions.
Synonyms:
1. to refine / to purify / to clarify – очищать
2. thoroughly / fully / completely – полностью
3. probability / likelihood – вероятность
4. moisture / humidity / dampness – влажность
5. hazard / danger – угроза, опасность
6. distinct / definite / plain – явный, определенный
7. rare / uncommon / scarce – редкий
8. to impart / relate / disclose – сообщать, передавать
|
|
|
9. to rotate / revolve – вращаться
Vocabulary notes:
1. sulphuric acid – серная кислота
2. sodium sulphate – сернокислый натрий
3. Gulf Stream – Гольфстрим
4. gritty – зернистый
5. rivet – заклепка
6. misfire – пропуски зажигания
7. coincide – совпадать
8. to reciprocate – поступательно двигаться
9. deposit – отложение, осадок
10. RPM – обороты в минуту
11. a spoke – спица, рукоять
12. clog – препятствовать
13. elbow – изгиб трубы
14. oil cooler – маслорадиатор
15. pitch – наклон
16. aeration – вентиляция
Exercise 2. SCANTHE TEXT AND BE READY TO DISCUSS IT.
Failure of the engine to start on air may be due to one or more of the following causes: starting air pressure too low, incorrect timing of starting air valves, one or more starting air valves stuck, compression relief gear out of order, stop valve in air line closed, or, if starting after working on the engine, the jacking gear may still be engaged.
Дата добавления: 2019-09-13; просмотров: 217; Мы поможем в написании вашей работы! |
Мы поможем в написании ваших работ!