
2. Valve seat insert
As shown in fig. 201, valve seat insert is used to
seal the cylinder by the close contact of its
internal conic surface with the valve conic
surface. Valve seat insert applies the powder
metallurgy steel, which has good cutting perfor-
mance and small thermal deformation. Valve seat
face is pressed into the cylinder head seat
through contraction. Its seal cone is processed
together with valve guide hole.
3. Valve tappet
Engine valve tappet adopts a short-cup form. It features good rigidity, light weight, large cam contact area, good lubrication
and reliability. Meanwhile, it facilitates the adjustment of the valve clearance. The material used for tappet is low-carbon
alloy steel.
4. Valve spring
Engine uses a single spring, cylindrical helical spring. The spring is 3.2mm in diameter with a central diameter of
21±0.1mm, and coiling wraparound ratio C = 6.56. The precompression quantity of intake valve spring is 7.8mm and that
of exhaust valve spring 7.5mm. To keep the spring in straight position under pressure, the two ends of the spring are
leveled in a range of 288 . It has 4.8 effective circles. The spring steel wire is made of 60SiCrVA, with good temperature
flexibility. The spring is processed with shot blast. In a free state, the total height of the spring is 39±0.3mm.
Fig. 201Seat Insert of Intake and Exhaust Valve
Fig. 200 Intake and Exhaust Valve
88
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 ...