Английский язык. Писарева Л.П. - 14 стр.

                                    ВАРИАНТ IV

GMT in the field of four-stoke engines.
   The four-stoke medium-speed formerly built by FIAT and now by GMT are the
types B300, C420 and 550. The latest development in the field is represented by the
550 engine.
  This engine has been designed by FIAT and developed by GMT to meet the
requirements of marine propulsion for high cylinder output and limited weight and
overall dimensions along with ease and simplicity of installation. The engines are also
designed for easy maintenance and economy of operation on heavy fuel oil.
  The 550SS engine has a bore of 550 mm by a stoke of 590 mm and develops a
maximum continuous output of 1200 bhp/ cylinder at 430 rev/ min , with a bmep of
17,9 kg /cm2 . The 550 engines a power range from 7200 to 24000 bhp per unit.
  The 550SS engine has a performance and characteristics based on extensive research,
design and development, among which are:
    • Evaluation and reduction of temperatures and thermal and mechanical stresses
       in the cylinder head, liner and piston.
    • Further investigation into the crankshaft bearings.
    • Study of the flow dynamics within the air ducts and exhaust ducts to improve
       the volumetric efficiency and utilization of the exhaust gases.
    • Study of the dynamics of the valve gear to reduce stresses and wear due to
       vibration.
  The low stoke/ bore ratio of 1:07 of the 550SS engine makes the engine compact.
The stoke reduction in relation to the bore permits an increase of overlap between main
journals and crankpins and thus reduces stresses.
  The cast iron bedplate and main engine frame are kept in compression by tie-rods to
avoid tensile stresses which are water-cooled cages for heavy fuel operation and ease of
maintenance.
  The camshaft is housed in a chamber separate from the crankcase so, that gas
escaping along valve guides and the cylinder head cannot accumulate in the crankcase.
Camshaft bearings are split in two to allow both the camshaft and bearings to be
removed sideways.

                     Words and expressions to be remembered:
To design                              Конструировать
To develop                             Разрабатывать
To meet the requirements               Отвечать требованиям
Cylinder                               Цилиндр
Output                                 Выходная мощность
Installation                           Установка
Maintenance                            Обслуживание, эксплуатация
Heavy fuel oil                         Тяжелое топливо
Bore                                   Внутренний диаметр цилиндра
Stoke                                  Ход поршня
Range                                  В пределах
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