Контрольная работа №4 вариант 4

I. Translate the text into Russian.

Cycles of operation

The cycle may be defined as the complete sequence of events that occur in the cylinder of an engine for each power stroke or impulse delivered to the crankshaft. Those events always occur in the same order each time the cycle is repeated.

Each cycle of operation is closely related to piston position and movement in the cylinder. Regardless of the number of piston strokes involved in a cycle, there are four definite events or phases that must occur in the cylinders.

1. Either air or a mixture of air and fuel must be taken into the cylinder and compressed.

2. The fuel and air mixture must be ignited, or fuel must be injected into the hot compressed air to cause ignition.

3. The heat and expansion of gases resulting from combustion must perform work on the piston to produce motion.

4. The residual or exhaust gases must be discharged from the cylinder when expansion work is completed.

In the 4-stroke diesel cycle, the piston makes four strokes to complete the cycle. There is one power stroke or power impulse for every four piston strokes, or two complete revolutions of the crankshaft.

In 2-stroke diesel cycle the piston makes two strokes to complete the cycle. There is one power stroke for every two piston strokes or for each revolution of the crankshaft.

II. Fill in what application(s) of the various types of engines are and compare the engines with regard to their advantage(s) and disadvantage(s).

Types of engines	Application(s)	Advantage(s)	Disadvantage(s)
Slow-speed engine
Medium-speed engine
High-speed engine
V-engine
In-line engine

III. The words of these sentences are mixed up. Write the sentences correctly.

Example: Placed ports are exhaust the cylinder on side.

Answer: Exhaust ports are placed on the cylinder side.

1. Is, this force, transferred, via, the crank shaft, to, the piston pin, and, the rod, connecting, the crank.

2. The stroke, upward, during, exhaust, the exhaust gases, of, the cylinder, are, most, from, expelled.

3. Are, the gases, residual, by, via, removed, the air, scavenging, the valves, exhaust.

4. The cycle, four, stroke, characterized, is, the fact, by, that, cycle, one, combustion, completed, is, revolutions, two, in, the crankshaft, of.

5. The forces, in, engines, crosshead, moving, the pistons, transferred, to, the crosshead, are, a piston rod, the piston, via, to, is, that, fixed.

IV. Read the following definitions and find the corresponding terms, which they explain. Translate completed sentences into Russian.

The gas exchange process	is a container used to store scavenging air and stabilize the air pressure
Scavenging	are the ports through which the air is forced into the cylinder.
Charging	is the air forced into the cylinder.
Marine diesel engine scavenging air box	is the removal of exhaust gases by blowing in fresh air.
Scavenge air	is the supply of fresh air and removal of exhaust gases.
The scavenge ports	is the filling of the engine cylinder with a supply or charge of fresh air ready for compression.

V. Translate from Russian into English.

1. Рабочий цикл четырёхтактного двигателя состоит из четырёх основных этапов — тактов и осуществляется на протяжении 4-х ходов поршня, т.е. за два обо­рота коленчатого вала.

2. ПЕРВЫЙ ТАКТ - ВПУСК: Поршень движется от ВМТ к НМТ, клапан впуска открывается, и топливная смесь поступает в цилиндр. Когда поршень достигает нижнего положения, клапан впуска закрывается.

3. ВТОРОЙ ТАКТ - СЖАТИЕ: Поршень идет вверх, топливная смесь сжимается. Когда поршень находится в нескольких миллиметрах от верхней мертвой точки (ВМТ), топливо, сжатое поршнем, воспламеняется.

4. ТРЕТИЙ ТАКТ - РАБОЧИЙ ХОД (РАСШИРЕНИЕ): После воспламенения горючего оно сгорает, горячие газы быстро расширяются, толкая поршень вниз (оба клапана закрыты).

5. ЧЕТВЁРТЫЙ ТАКТ - ВЫПУСК: По инерции коленвал продолжает свое вращение, поршень идет наверх. Одновременно открывается выпускной клапан, и отработавшие газы выходят в выхлопную трубу. При достижении поршнем ВМТ, выпускной клапан закрывается.