Due to the change of environmental conditions and operating conditions, the thermal state of the engine changes at all times.  Therefore, the cooling strength of the engine must be adjusted at any time.  For example, in the summer, the engine works at low speed and under high load, the temperature of the coolant is very high, the fan should rotate at high speed to increase the cooling air volume and enhance the cooling capacity;  And in the cold winter, the fan continues to work becomes meaningless when the coolant temperature is low.  Not only the engine power is consumed in vain, but also a lot of noise is produced.  

 In many parts of the north, under 10 degrees celsius for more than 100 days, the actual engine cooling fan does not work, and the fuel consumed will be a very serious waste.  This also explains why the clutch can not be locked.  

 Principle of silicon oil fan clutch

 Unlike the ordinary rigid fan, the silicone oil fan clutch, using silicone oil as the medium, uses the silicone oil shear adhesion to transfer torque.  

 The space between the front cover of the fan clutch and the moving plate is the oil storage cavity, and the high viscosity silicone oil is stored here.  

 The key sensing component is the spiral double metal plate temperature detector on the front lid, which generates a distortion to control the control valve piece to control the silicone oil into the working chamber engaging the drive shaft and the fan.  

 When the temperature is low, the control valve does not open, and the silicone oil stored in the oil storage cavity cannot flow into the working chamber at this time.  There is no silicone oil in the working cavity, the torque on the active plate cannot be transferred to the slave plate, and the clutch is separated.  

 When the load of the benchi accessories engine increases and the coolant temperature rises, the high temperature air flow is blown on the bimetallic temperature detector, so that the bimetallic strip is heated and deformed, and the drive pin of the valve plate and the control valve plate deflection angle.  After the air temperature exceeds a certain temperature, the oil inlet hole is opened, and the silicone oil in the oil storage cavity enters the working chamber through this hole.  The torque of the active plate is transmitted to the clutch housing through the shear stress of silicone oil, which drives the fan to rotate at high speed.  

 Frequent failure analysis

 1. the spiral double metal plate temperature sensor fracture, which causes the fan not to turn.  

 2. the fatigue failure of the spiral double metal plate temperature sensor, the high induction condition of the temperature causes the fan not to work in time to affect the engine performance.  

 3. the oil storage cavity and the working cavity seal are not strict, and the loss of silicone oil affects the torque transmission.  

 For the above problems, many kayou choose to lock the fan clutch to solve the high temperature of the engine.  Even kayou is directly welded to death, which is different from the ligation operation, it is all right, it can only be used temporarily on the road, not long – term use.  

 First, the locked fan clutch will lose a lot of power, and it is understood that the power required by the rigid connected cooling fan is 3 – 5 % of the engine power, and the fuel consumption is amazing.  

 Secondly, silicone oil can play a certain buffer, even in the joint state, the speed of the fan is smaller than the drive shaft, will cause a large impact on the connection, heavy truck fan diameter is very large, inertia also large, fans following the Baotou northern benchi accessories engine rotation, the engine start to stop very fast, the fan clutch connection will have a strong impact, long time under the inertial effect, the situation will cause the fan will fall, also may damage the water tank, should not be underestimated.  

 With the progress of science and technology, the fan design of the cooling system has experienced great changes from the earliest rigid fan to the benchi silicone oil clutch fan in the north of Baotou, and now the advanced electromagnetic clutch fan and the electronic silicone clutch fan.  

 1. rigid fan

 After the above description, compared to everyone has a certain understanding, the rigid connected fan is directly affected by the engine speed, the engine low speed operation, cooling system temperature is forced to heat, resulting in low engine temperature, winter engine heating difficulties.  

 It must have been seen that some of the older truck's engines are covered with quilts, on the one hand, in order to prevent the fan from forced cooling, to ensure the engine temperature to enable it to start.  

 2. silicone oil clutch fan

 Silicone oil fan, through silicone oil as the medium, using the high viscosity of silicone oil to transfer torque, through the double temperature metal deformation structure of the " coupler" to achieve the temperature control of the fan, fan speed is controlled by temperature, to avoid the low temperature operation.  But this is only analog operation, it is difficult to achieve accurate cooling system constant temperature, there is fluctuation.  

 3. electromagnetic clutch fan

 Electromagnetic clutch fans, through the control switch, intelligent control unit or engine ECU communication to accurately control the fan speed, to further control the cooling system temperature, to achieve the two-stage or three-level speed regulation, at present and Weichai engine products are selected to install this system.  

 4. electronic silicone oil clutch fan

 The electronic control type clutch of the electronic silicone oil clutch fans is different from the traditional double metal temperature sensing control mode, by directly reading the engine control module ECU signal, by the fan clutch internal electromagnetic valve, according to the information provided by the engine temperature sensor, control the cooling fan speed.  To achieve a more accurate and rapid response.  

 :: afterword

 Choose to drive a truck, must learn to operate, the engine is the core part of the truck, and the fan as cooling system, the engine work efficiency plays a vital role, do not lock it because of its damage.  

 With the current domestic engine manufacturers are selecting the electromagnetic clutch fan and the electronic control silicone fan, the effect of oil saving is more obvious, the final profit is still us, we should be more willing to accept this new technology.