4. Decide whether the following statements are true or false.

1. Most automotive engines are five-stroke cycle engines.

2. There are four strokes in one cycle.

3. Failure of the air-fuel mixture to ignite may be caused by a hot engine.

4. The greater the ratio of an engine, the less power it delivers per unit of fuel.

5. Most cylinder blocks and heads are made of silver.

6. A flywheel keeps engine speed steady.

7. Water from the radiator is circulated through the water jacket to heat the engine.

8. A centrifugal water pump is never used in automobiles.

9. A thermostatic valve prevents water from circulating through the radiator.

10. Some engines have no liquid coolant.

5. Answer the following questions.

1. What is a four-stroke cycle engine?

2. What strokes does a cycle consist of?

3. Why is the compression ratio an important characteristic of engine operation?

4. What is measured in octane ratings?

5. What causes of engine knock do you know?

6. What may cause premature ignition?

7. What is a car horse rating?

8. How do the pistons turn the crankshaft?

9. What is attached to the crankshaft? What is it for?

10. How does water cool the engine?

11. What is a centrifugal water pump used for?

12. How long does a thermostatic valve prevent water from circulating through the radiator?

6. Match the terms with their definitions.

a) crankshaft, b) piston, c) complete, d) pump, e) liquid, f) valve, g) horse-power

1. To make sth. whole or perfect;

2. A metal rod in a vehicle that connects the engine to the wheels and helps turn the engine's power into movement;

3. A unit for measuring the power of an engine;

4. A part of an engine that consists of a short cylinder that fits inside a tube and moves up and down or backwards and forwards to make other parts of the engine move;

5. A machine that is used to force liquid, gas or air into or out of sth.;

6. Not a solid or a gas;

7. A device for controlling the flow of a liquid or gas, letting it more in one direction only.

7. Match the words with the synonyms.

1) need	5) space	a) function	e) although
2) steady	6) though	b) room	f) require
3) operate	7) heavy	c) regular	g)lessen
4)occasionally	8) lower	d) ponderous	h) sometimes

8. Match the words with the antonyms.

1) up	5) failure	a) solid	e) bottom
2) inside	6) cool	b) leave	f) heat
3) maximum	7) liquid	c) outside	g) down
4) top	8) enter	d) minimum	h) success

9. Fill in the correct prepositions.

1. The activities that take place ___ the engine cylinder can be divided ___ four strokes.

2. A power impulse is transmitted ___ the engine crankshaft ___ the connecting rod and crank.

3. This creates a fairly high pressure ___ the cylinder.

4. A flywheel is a heavy, steel wheel attached ___ the end ___ the crankshaft.

5. The mixture of gasoline and air is delivered ___ the cylinder ___ the fuel system.

6. Gasoline can operate ___ a specified compression ratio which is measured ___ octane ratings.

7. Ignition of the air-fuel mixture is caused ___ a warm engine.

8. What does the efficiency of the engine depend ___?