Chapter 22. -DIESEL AND GASOLINE ENGINES 



4 CENTRIFUGAL VALVES 



ROTATING RESERVOIR 



PRIMARY ROTOR (IMPELLER: 

 COLLECTOR RING 



SECONDARY ROTOR (RUNNER) 



LUBE OIL FROM ENGINE 3 GPM - 10 PSI 



LUB OIL RETURN TO ENGINE 

 (GRAVITY) 



SCOOP TUBE 



PISTON VALVE CONTROL TUBE 



4 QUICK-EMPTYING PISTON VALVES 



Figure 22-44.— Scoop control hydraulic coupling. 



75.262 



interrupted and the oil in the control tubes will 

 be discharged through the orifice in the outer 

 end of the piston housing. This releases the 

 pressure on the piston and allows it to move 

 outward, thus opening the port for rapid dis- 

 charge of oil. Resumption of oil flow from the 

 scoop tube will fill the control tubes; and the 

 pressure will move the piston to the closed 

 position. 



When the engine is started and the coupling 

 is filled with oil, the primary rotor turns with 

 the engine crankshaft. As the primary rotor 

 turns, the oil in its radial passages flows out- 

 ward, under centrifugal force. (See arrows in 

 fig. 22-42.) This forces oil across the gap at 

 the outer edge of the rotor and into the radial 

 passages of the secondary rotor, where the oil 

 flows inward. The oil in the primary rotor is 

 not only flowing outward, but is also rotating. 

 As the oil flows over and into the secondary 

 rotor, it strikes the radial blades in the rotor. 



The secondary rotor soon begins to rotate 

 and pick up speed, but it will always rotate 

 more slowly than the primary rotor because of 



drag on the secondary shaft. Therefore, the 

 centrifugal force of the oil in the primary rotor 

 will always be greater than that of the oil in the 

 secondary rotor. This causes a constant flow 

 from the primary rotor to the secondary rotor 

 at the outer ends of the radial passages, and 

 from the secondary rotor to the primary rotor 

 at the inner ends. 



The power loss in the hydraulic clutch is 

 small (3 percent) and is caused by friction in 

 the fluid itself. This means that approximately 

 97 percent of the power delivered to the pri- 

 mary rotor is transmitted to the reduction gear. 

 The loss power is transformed into heat that is 

 absorbed by the oil— which is the reason for 

 sending part of the oil through a cooler at all 

 times. 



MAINTENANCE 



Keeping an internal combustion engine (diesel 

 or gasoline) in good operating condition demands 

 a well-planned procedure of periodic inspection. 



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