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6.Make a list of words characterizing the starting motor.
7.Find out a word or a word expression in the text or remember a similar meaning to the following:
the fluid |
enough |
to come in |
gear |
a cell |
a wheel |
to situate |
a way |
to work |
to pass |
the velocity |
movement |
8. Find the answers to the questions given below:
1)What is the liquid fuel mixed with?
2)Where is the liquid fuel vaporized?
3)Where is the fuel-air mixture ignited?
4)What mechanism is located at the engine?
5)What is the function of the generator?
6)What is the starting motor?
7)What happens to a driving pinion?
8)What is the highest position of the piston called?
9)What is the lowest position of the piston called?
10)What is “the combustion space”?
11)Where is the fuel-air mixture compressed?
12)What is the fuel-air mixture compressed by?
13)What is it ignited by?
9. Give synonyms to the following words:
to enter |
top |
to locate |
bottom |
speed |
the path |
to actuate |
to cover |
a driving pinion |
the motion |
to crank |
to ignite |
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10. Here are the answers to the questions. Write down the questions.
Answers: |
Questions: |
1)The liquid fuel is mixed with air.
2)The fuel-air mixture enters the cylinder.
3)The generator is located at the engine.
4)The highest position of the piston in the cylinder is called “top dead centre”.
5)The lowest position of the piston in the cylinder is called “bottom dead
centre”.
6)The fuel-air mixture is compressed
7)by the upward movement of the piston.
11.Look through the text again. Make a plan of the text.
12.Compose a short summary of the text using the following expressions:
The text informs/reports. . The text dwells upon ... .
The text runs/comments on ... .
In conclusion it should be noted ... .
Unit IV
The working method of a four-stroke cycle carburetor engine
Let us analyze the working method of a four-stroke cycle carburetor engine, as an example.
With All the carburetor engines, the fuel-air mixture is sucked into the cylinder by the downward movement of the piston. The fuel-air mixture is broken up and partially vaporized in the carburetor; then, it is ignited by an incorporated ignitionsupplying device, the spark plug.
In case of the four-stroke cycle engine, the path covered between top dead centre and bottom dead centre and vice versa is a stroke. Each stroke is accompanied by one-half of a crank-shaft evolution. The complete cycle requires the following four strokes.
Suction stroke: the piston moving downward takes in fuel-air mixture through the open intake valve, while the exhaust valve is closed. Immediately after the piston has reached the bottom dead centre, the intake valve is closed. The first stroke has
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been finished. The crankshaft has turned one-half of a revolution.
Compression stroke: with the valves closed the fuel-air mixture is compressed by the upward stroke of the piston toward top dead centre. The crankshaft has finished one full revolution.
Power stroke: before the piston has reached the upper dead centre, ignition is performed. The compressed fuel-air mixture burns, the gases expand due to the heat of combustion and force the piston go downward. The valves are still closed. The crankshaft has turned one and one half of a revolution.
Exhaust stroke: after it has been finished, the-piston moves upward to the top dead centre and pushes the burned gases out of the cylinder through the open exhaust valve. As soon as the piston has reached the top dead center, the exhaust valve is closed and the intake valve is opened. Now, the crankshaft has completed two revolutions. The next cycle can begin.
Tasks
1. Read and guess the meaning of the following words and phrases:
to analyze, the working method, cycle, fuel-air mixture, the path, top dead centre, bottom dead centre, one-half, revolution, ignition, the gases, force.
2. Give synonyms to the words:
to suck |
top |
intake valve |
combustion |
movement |
bottom |
exhaust valve |
to push |
to break up |
to accompany |
to finish |
burned gases |
|
|
||
the path |
complete |
perform |
|
|
|
|
3. Give opposites to the following words:
downward movement |
open |
partially |
upper |
top |
closed |
bottom |
to finish |
to take in |
|
4. Correct the statements which are wrong (use “false” or “true”).
1. The fuel-air mixture is sucked into the cylinder by the upward movement of the piston.
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2.Each stroke is accompanied by one-half of a crankshaft revolution.
3.The piston moving upward takes in a fuel-air mixture through the closed intake valve.
4.The exhaust valve is opened at this time.
5.During compression stroke the crankshaft has finished two full revolutions.
6.As soon as the piston has reached the top dead center, the exhaust valve is closed and the intake valve is opened.
5. Choose the right Voice of the verb.
1.The fuel-air mixture (sucks, is sucked) into the cylinder by the downward movement of the piston.
2.The fuel-air mixture (is broken, breaks).
3.The path covered between top dead center and bottom dead center (is called, calls) the piston stroke.
4.The complete cycle (is required, requires) the following four strokes.
5.The piston (takes, is taken, are taken) in the fuel-air mixture.
6.The exhaust valve (is closed, closes, closed).
7.The first stroke (has been finished, finishes, finished).
8.The crankshaft (has finished, has been finished).
6. Find the answers to the following questions:
1.Where is the fuel-air mixture sucked into?
2.What happens to the fuel-air mixture in the combustion chamber?
3.What is a stroke?
4.What is each stroke accompanied by?
5.How many strokes does the complete cycle require?
6.Is the exhaust valve closed during the suction stroke?
7.What is the fuel-air mixture compressed by?
8.When is ignition performed?
9.Why do the gases expand?
10.What forces the piston to go downward?
11.When can the next cycle begin?
7.Write out the verbs in Present Simple Active.
8.Write out the verbs in Present Simple Passive.
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9.Write out the verbs in Present Perfect Active.
10.Write out the verbs in Present Perfect Passive.
11.Find in the text the words and phrases with similar meaning:
downward motion |
in the direction to |
the way |
takes place |
the highest position of the piston |
push |
the lowest position |
to revolve |
inlet valve |
spent gases |
outlet valve |
as soon as |
full cycle |
|
12. Correct the mistakes in the sentences given below.
1.The fuel-air mixture is sucks into the cylinder.
2.The fuel-air mixture broken up.
3.Each stroke is accompany by one-half of a crankshaft revolution.
4.The piston moves downward takes in the fuel-air mixture.
5.The first stroke been finishing.
6.The fuel-air mixture be compress by the upward stroke of the piston.
13. Give a short summary of the text using the following phrases:
The text deals with ...
We learn from the text that ...
In conclusion it should be noted that ...
Unit V
Cylinders
Cylinders and cylinder heads of the engine are made either of grey cast iron or cast light metal. In general, the combustion chamber is located in the cylinder head to permit an objectionable and continuous machining of combustion space and working surface of the cylinder. In case of valve-in-head engines, the cylinder supports the valves and the valve operating mechanism. In addition, the cylinder head comprises the induction and exhaust ducts.