W
hen the engine works, cylinder head bears relatively high thermal load and mechanical load. In order to ensure supe-
rior combustion and reliable work, cylinder head must optimize combustion chamber, intake duct, exhaust duct and cooling
water chamber should be arranged rationally. It should have relatively high heat transmissibility, sufficient strength and
rigidity, in addition, it should also feature light weight and compact structure.
Structural characteristics of cylinder head:
1. Adopts cast aluminum alloy: 439mm long, 116mm high and 10kg in weight.
2. Combustion chamber is pent-roof shape. Spark plug is in the middle part.
3. The angle between intake valve and exhaust valve is 22º, angle of intake duct to horizontal plane is 38º-40º and exhaust
duct is arranged horizontally. Intake duct has smooth wall and small resistance. Admission tends to form rotational flow. It
also features good exhaust and purge effect.
4. The structure is relatively complicated; there are four combustion chambers, 16 valves, double camshaft, ten bearing
holes, 16 tappet holes, water chambers with different shapes, jet holes, oil passage, gear chamber, eight intake/exhaust
ducts, many bolt holes, a lot of spacer plates and reinforced ribs. Valve stem guide and valve seat that are made of alloy
cast iron and refractory steel are pressed into cylinder head by means of shrinking (Fig. 71).
Chapter 3 Cylinder Head Assembly
Section 1 Structural Characteristics of Cylinder Head
1. In the process of removing sub-assy. of cylinder head, use special repair tools in the sequence shown in Fig. 33, loosen
and remove cylinder head bolts in several equal operations. Incorrect sequence of bolts removing might cause warping or
breaking of cylinder head. At the same time, prevent distortion and damage of fasteners caused by removal of cylinder
I. Detach
Section 2 Detach, Assembly and Repair of Cylinder Head
Fig. 71 Cylinder head view
45
Содержание JL481Q
Страница 1: ......
Страница 9: ...5 Fig 3 Components Assembly Drawing of MR479Q MR479QA Engine ...
Страница 10: ...6 Fig 4 MR479Q MR479QA Engine and Its Power System ...
Страница 11: ...7 Fig 5 Assembly Drawing of Engine and Its Auxiliaries MR479Q MR479QA ...
Страница 12: ...8 Fig 6 Electronic Control Fuel Injection System in Engine MR479Q MR479QA ...
Страница 13: ...9 Fig 7 Front view of Engine JL481Q MR481QA ...
Страница 14: ...10 Fig 8 Sectional elevation of Engine JL481Q MR481QA ...
Страница 15: ...11 Fig 9 Electronic Control Fuel Injection System in Engine JL481Q MR481QA ...
Страница 21: ...17 Fig 13 Exterior Feature of JL481Q Engine Power Me N m Torque Pe Kw ge g kwh Fuel Consumption Ratio ...