КОНТРОЛЬНАЯ РАБОТА № 1 - Вариант № 1
1. Прочитайте и устно переведите весь текст. Перепишите и письменно переведите 1, 2, и 3 абзацы текста.
SCAVENGING
1. In the two-stroke cycle engine the scavenging air is admitted through scavenging ports located at the bottom of the cylinder.
2. In the scavenging arrangement we describe, the exhaust ports are placed on one side of the cylinder and on the opposite side are scavenging ports. The exhaust ports are slightly higher than the scavenging ports so that the piston uncovers the exhaust ports first, thus allowing the pressure in the cylinder to fail before the scavenging ports are opened. By the time the scavenging ports are uncovered the pressure in the cylinder has fallen to atmospheric and the scavenging air rushes in. By inclining the scavenging ports and shaping the piston head, the entering air is deflected upward and sweeps the burned gases out of the upper part of the cylinder and out through the exhaust ports. When the piston covers the ports on its up stroke, the air is trapped in the cylinder and then is compressed. This arrangement of scavenging does away with the necessity for the scavenging valves in the cylinder head. The only cylinder head valves then required are the spray valve and starting air valve. This simplifies the head, makes cooling easier and reduces the liability to crack.
3. There are a number of different systems in use for admitting scavenging air.
4. In 2-stroke Diesel engines the following three methods are used for the scavenging of the cylinder: cross scavenging system (Sulzer), loop scavenging (M.A.N.) and uniflow scavenging system (B. & W.).
5. Uniflow scavenging is of greater advantage when compared to the two other systems. It ensures better removal of all residues of the combustion products.
6. By giving the scavenging port an inclined shape, a rotary motion of the scavenging air is obtained, which means that the air ascends through the cylinder without mixing with the combustion gases, consequently, the latter are forced out of the cylinder, no residue being left.
7. As a consequence of the advantageous flow conditions, this system requires less surplus air and less scavenging work, too.
8. The rotary motion of the scavenging air ensures a very even mixture of air and oil, and this in its turn will ensure an unusually good combustion of the oil.
2. Ответьте на вопросы по тексту.
1). Where are the exhaust and the scavenging ports placed?
2). What happens with the scavenging air by the time the scavenging ports are uncovered?
3). There are a number of different system in use admitting scavenge air, aren’t there?
4). What methods are used for the scavenging of the cylinder in 2-stroke Diesel engines?
3. Переведите следующие выражения на английский язык:
1) двухтактный двигатель;
2) нижняя часть цилиндра;
3) клапан пускового воздуха;
4) продувочное окно;
5) головка поршня;
6) поперечная система продувки;
7) продукты сгорания;
8) прямоточно-клапанная система продувки;
9) избыточный;
10) вращательное движение.
4. Найдите в предложениях подлежащее и сказуемое, подчеркните одной и двумя чертами соответственно, определите время и залог. Переведите.
1). The scavenging air is admitted through scavenging ports located at the bottom of the cylinder.
2). This simplifies the head, makes cooling easier and reduces the liability to crack.
3). The exhaust ports are slightly higher than the scavenging ports.
4). The following three methods are used for the scavenging of the cylinder in 2-stroke Diesel engines.
5). It ensures better removal of all residues of the combustion products.
5. Образуйте от глаголов, данных ниже, Причастие I и Причастие II. Переведите.
- to arrange - to reduce
- to fail - to compare
- to sweep - to obtain
- to compress - to require
- to show - to make
6. Напишите резюме.
