Answer: The correct adjustment of fan belt and air compressor belt directly affects the normal running of the car. The fan, crankshaft and generator of automotive diesel engine use a set of belts, which are collectively called fan belts. Too tight or too loose fan belt: If the fan belt is too tight, the radial clearance between the water pump bearing and the generator bearing will be reduced, resulting in premature damage or burning of the water pump bearing and the generator bearing. At the same time, because the belt is too tight, the friction and wear increase and the working temperature of the belt increases, which greatly reduces the service life of the belt. The fan belt is too loose, the generator speed is insufficient, and the power generation is reduced. At the same time, because the generator and the water pump use a set of belts coaxially, the circulating cooling water supply of the diesel engine will be insufficient because of the insufficient speed of the water pump. The fan speed will be too low, which will weaken the heat dissipation of the water tank and increase the working temperature of the diesel engine. Too tight or too loose belt of air compressor: too tight belt of air compressor will reduce the radial clearance of crankshaft of air compressor, and it is not easy to form lubricating oil film between crankshaft and bearing, which is easy to cause burning of crankshaft of air compressor. The belt of the air compressor is too loose, the speed of the air compressor is insufficient, and the displacement and working pressure can't meet the requirements, which leads to the difficulty of automobile braking (Dongfeng EQ 109OF2D vehicle diesel engine air compressor requires the displacement of 85Vmin and the working pressure of 784kPa). Adjustment of fan belt and air compressor belt of Dongfeng EQI09OF2D vehicle diesel engine: The adjustment of fan belt is realized by adjusting the relative position of the generator (loosen and tighten the fixing bolt of the adjusting arm of the generator, and pull the adjusting arm up or down to tighten the belt). Suitable belt tightness is: press the belt with a force of 30N-5ON. Its deflection is 10 mm- 15 mma. When adjusting the fan belt, you should also pay attention to check whether the front end faces of the three pulleys of crankshaft, water pump and generator are on the same plane and cannot be twisted back and forth. Belt deformation is mainly caused by looseness of fastening bolts between air compressor and air compressor bracket, generator and generator bracket, and fastening bolts between crankshaft and generator and air compressor. In case of this phenomenon, we should find out the original reason according to the fault situation and deal with it in time. To adjust the belt of the air compressor, loosen the three fastening bolts on the base bracket of the air compressor and turn the adjusting bolts clockwise to tighten the belt. Belt tightness: press the belt with a force of 30n-5on (3kg-5kg), and its deflection is 15mm-20mm.