Cooling and starting preheating system motor grader DZ-98B

The cooling and starting preheating system serves for forced heat transfer from the diesel engine and compressor, for preheating the cooling liquid and oil during the diesel engine start-up at ambient temperatures below zero, for feeding the warmed-up liquid to the cab heater. The cooling system of the engine is of a closed liquid type with forced circulation of the cooling liquid.
The cooling and preheating system of the YAMZ-8482.10-01 engine consists of the following main units: the water pump 10, the radiator 4, the expansion tank 1, the thermostat box 19, the fan with hydromechanical drive, the PJD-30 starting preheater.

The fan hydromechanical drive maintains an automatical change of the fan rotation frequency which is attached to the driven shaft of the hydraulic coupling according to the temperature change of the cooling liquid. The rotation frequency of the driven shaft hydraulic coupling depends on oil consum-ption through it, which changes with the cooling liquid temperature change. The thermostats allow a liquid flow circulation at the cooling liquid temperatu-re below 70 0C not passing through the radiator.
Simultaneous automatic work of the fan and the thermostats maintain the optimal thermal operating conditions of the engine and its fast warming-up at starting. In this case at ambient temperatures below zero the engine bonnet should be kept closed with the warming hood and the radiator should be kept closed with the shutter (if it is available).
At ambient temperatures below zero the grader should operate with antifreezing solution used as the cooling liquid.
The thermal condition of the engine is checked by instruments, which record the temperature of the cooling liquid in the cooling system and the oil in the lubrication system.
Warmed liquid for operation of cab heater is supplied by means of heater cock which is arranged above the engine. In the warm season the heater cock should be closed.
Filling of the cooling and preheating system is executed through a filler neck of the expansion tank. The liquid is drained, when the cocks 9,14,18 are opened.
The cooling and starting preheating system of the Y1D6-TK-C5 engine can be made wit-hout the expansion tank using the radiator, which has the filler neck and is equipped with a shutter.

Filling this system is performed through the radiator filler neck. The liquid is drained when the cocks of the engine water pump and the oil feed pump are open.
The cooling and starting preheating system of the YAMZ-240G engine is different from the system of the YAMZ-8482.10-01 engine only by a placement of the component parts and pipelines as well by absence of the thermostat box.
The cooling and preheating system of the YAMZ-238HD3 and YAMZ-238HD2 engines has the following features.
1). The fan drive hydraulic coupling is absent.
2). The cooling liquid is supplied into the radiator via two pipes with a thermostat in each of them.
3). The cock for switching on the warmed-up water circulation through the cab heater is placed near to the engine tray from the right in direction of motor grader travel, closed to the end of hose, which removes the liguid from the preheater.
4). Three drain cocks are provided in the system in order to drain the liquid and if necessary there are the drain plugs on the boiler and the heater pump unit.
The radiator 4 is of a tubular-band, four-row type without the filler neck.
The radiator is attached on four supports by the rubber shock absorbers to two pillars placed on the motor grader frame. The cooling liquid is delivered into the radiator upper manifold while the same liquid is discharged from the lower manifold by means of the water pump. The radiator upper manifold is connected with the expasion tank by hose.
The expasion tank 1 stands duty as a reservoir for the cooling liquid expanded in heating and serves for filling the cooling liquid in the engine cooling and starting preheating system in the cooling and preheating system. The surplus liquid and steam from the radiator enter the expasion tank, while in case of rarefaction in the system a certain amount of liquid flows back into radiator and prevents formation of the air plugs.