T
he function of piston & connecting rod mechanism is to convert pressure of working substance in the cylinder into power
by rotation of the crankshaft and flywheel assy. Piston & connecting rod mechanism mainly consists of piston, piston rings,
piston pin, connecting rod body, connecting rod cap, connecting rod bolts, nuts and connecting rod bushing. The disas-
sembled piston & connecting rod mechanism of engine is illustrated in Fig. 173. The consolidation degree and power per
unit piston area of engine are high. The structures of canopy piston top, minus offset and semi-floating piston pin allow less
motor noise and more working flexibility.
Chapter 4 Piston & Connecting Rod Mechanism
Because short piston and low compression height helps to lighten piston weight and reduce reciprocating inertial force,
both of the compact engines can run at a higher speed.
Two gas rings and one oil ring is fitted on the piston head. The height of the first gas ring is 3mm and that of the secondary
one is 2.5mm. Eight oil feed-back holes of 2mm in diameter distribute symmetrically at the both sides of the pin hole on the
bottom of oil ring slot, and a piston pin lubricant track is designed on piston pin seat, which permits the continuous suction
of lubricant. To achieve fine thermal conductivity, heating surface on the piston top introduces the structure of smooth
transition, and a big transition circular is adopted to connect top plate and ring belt.
1. Structural Characteristics of Piston, Piston Pins and Piston Rings
1. Piston
The main functions of piston are to undergo high temperature and high pressure of working substance in cylinder, keep
airtightness of cylinder together with piston rings, and transfer heat to cylinder walls. The piston used in the engine is made
of cocrystallization aluminum-silicon alloy. Integral and tin-coated, it reduces the possibility of napping. Combustion cham-
ber, formed by piston top and cylinder cap, provides a large room for extruded gas. The projection of combustion chamber
offers a good shape for organizing whirl currents of extruded gas, and advances the features of high thermal efficiency,
small chill area and low knocking. The structure of piston is shown as Fig. 174.
Section 1 Construction of Piston & Connecting Rod Mechanism
1.First gas ring 2.Secondary gas ring 3.Combination oil ring 4.Piston pin 5.Piston
6.Connecting rod 7.Connecting rod bushing 8.Connecting rod cap 9.Connecting rod nut
Fig 173 Disassembled piston & connecting rod mechanism
Fig. 174 Structure of piston
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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 ...