2. Translate the sentences. Pay attention to the words in italics.

1. The heart has four chambers.

2. How do you measure the volume of a gas?

3. A spark ignites the fuel in a car engine.

4. He gradually accumulated an impressive collection of paintings.

5. A dipstick is used to measure how much oil is left in an engine.

6. Highway is a broad main road which often leads from one town to another.

7. Cooled air is circulated throughout the car.

8. The car’s performance on corners needs to be improved.

9. Flywheel keeps a machine working at an even speed.

10. Speed depends on the transport stream.

11. The valves of the heart and blood vessels allow the blood to pass in one direction only.

12. There is a substance used in antifreeze for car engines.

13. “Afterburner” can be translated as “дожигатель”.

14. He had to drive slowly over the uneven surface of the road.

15. He pushed the box very hard down the slope, but friction gradually caused it to slow down and stop.

16. The term “dipper” has different meanings but in automobile engineering it means an oil pump.

Part I

3. Read text a carefully paying attention to the words in bold type.

А. Four-Stroke Cycle Engine

Most automotive engines are four-stroke cycle engines. Each up and each down movement of the piston is a stroke. Four strokes are needed to complete one cycle. The strokes of the cycle are the intake, compression, power, and exhaust strokes.

An important characteristic of engine operation is the compression ratio. This is the relation of the size of the piston chamber when the piston is at its lowest position to its size when the piston is in the top position. If the total volume of a cylinder is, for example, 35 cubic inches (574 cubic centimetres) and the piston at the top of the stroke leaves a space of 5 cubic inches (82 cubic centimetres), the air-fuel mixture has been compacted to one seventh of its original volume, and the compression ratio is seven to one.

The ability of gasoline to operate at a specified compression ratio is measured in octane ratings. Gasoline rated too low for a specified engine may ignite prematurely and produce a pinging sound, called knock.

Another cause of engine knock is accumulation of soot (carbon) as a hard deposit inside the cylinder. Pieces of carbon become red-hot and act like a spark to cause premature ignition. Occasionally running the engine at high speed or driving the car at maximum highway speeds does much to avoid or clean out this accumulation of carbon. Missing is a term used to describe failure of the air-fuel mixture to ignite. It may be caused by a cold engine. The compression ratio is a good indication of engine performance. The greater the ratio of an engine, the more power it delivers per unit of fuel. An automobile's horsepower rating is also usually given. One horsepower is the force needed to move 33,000 pounds (15,000 kilograms) one foot (30 centimetres) in one minute.

The cylinders of the engine are moulded into a cylinder block, a heavy block of metal. The cylinder head is a separate casting that is bolted to the block. Most cylinder blocks and heads are made of cast iron, though some are made of aluminium. The pistons turn the crankshaft by means of connecting rods. Attached to the crankshaft is a heavy flywheel, which helps keep engine speed steady.

Cooling System. Water from the radiator is circulated through the water jacket, or passages around the cylinders, to cool the engine. A centrifugal water pump generally is used in automobiles. The water, entering at the centre, is caught by the vanes of the pump and is thrown to the outside by centrifugal force. The pressure imparted to the water carries it to the pipe leading to the water jacket. A thermostatic valve prevents water from circulating through the radiator until the temperature has reached a degree suitable for efficient engine operation.

Some engines depend on a flow of air over the engine and have no liquid coolant.

Comprehension Check - 1