Analysis Of Thermal Characteristics Of Wet Dual Clutch Coupled Multi System

As an important part of modern intelligent automobile,wet dual clutch can realize the shift of gear without interrupting the output power,and it has a deep influence on the development of modern automobile industry.It has now become the focus of the major automobile manufacturers.In the shift pr?ess of wet dual clutch,the friction loss power of rough torque and drag torque will produce a lot of heat.If the lubricating oil can not take away the heat in time,the remaining heat will cause the temperature of the friction pair to be too high,resulting in the failure of the warpage and overheating of the friction pair.Therefore,in this paper,a new development wet dual clutch is taken as the research object,and the method combining theoretical analysis and numerical simulation is applied,and considering the dynamics coupled between the clutch and the vehicle system,the heat production and thermal characteristics of the clutch during the transient working process are simulated and analyzed.The main work and conclusions are as follows:(1)In view of the structural characteristics and working principle of a wet dual clutch,the friction calculation formula with hyperbolic tangent function and Reset integral formula are compared and analyzed.This paper expounds the calculation formula of the drag torque,and establishes the AMESim model to analyze the influence factors of the lubricating oil temperature,flow rate and the clearance of the friction pair on the drag torque.The formula for calculating the normal pressure drop is derived,and the attenuation of the internal and external friction pairs under different equivalent friction coefficients is analyzed.(2)According to the structural characteristics and lubrication mode of a wet dual clutch,the heat and heat transfer path of the clutch is drawn.Based on the lumped parameters and the theory of heat network,the clutch structure and the fluid field of the lubricating oil are discretized.The different heat transfer modes are solved by logical control,and the thermal resistance calculation method is determined according to the structure and heat transfer mode of the wet dual clutch.The heat transfer model is established and the package is integrated.(3)The heat flow distribution theory is introduced and the integrated package model is established,and the final heat and heat transfer model is coupled,and the accuracy of the simulation model is verified by experimental.The results show that the friction pair are the two cases of internal friction pair joint and external friction pair,The equilibrium temperature of friction pairs and lubricating oil is in good agreement with the experiment.(4)Based on the whole vehicle system,a thermal analysis model coupled muilty system for wet dual clutch is established.Under the climbing condition and starting speed and continuous gear shifting condition,The temperature variation trend of wet dual clutch is analyzed.And by normalizing and programming the results of simulation data,the temperature distribution diagram of wet dual clutch is obtained intuitively.The results show that:(1)According to the clutch engagement condition,the internal and external friction pairs produce heat alternately with the drag torque,and the sudden increase in heat generation occurs with the drag torque when the gear is engaged.(2)According to the clutch gear,the highest temperature region of wet dual clutch occurs alternately in the internal and external friction pairs,and the temperature rise of the friction pair during the shifting process is obviously greater than the back-shifting.(3)Due to the influence of normal pressure attenuation,the heat production of the internal and external friction pairs is attenuated in different proportions.When the attenuation is serious,the temperature of the internal steel discs 1 to the internal steel discs 3 decreases along the direction of attenuation.(4)When the vehicle continues to shift and climb uphill,the temperature of internal friction pair is higher than the external.The lubrication and cooling of the friction pair in the inner clutch should be strengthened.(5)When the vehicle is started and continuously up-shifted without a ramp,the temperature rise of the external friction in the 1 gear starts is greater than the 3 or 5 gear,and the temperature rise of the internal friction pair in the 2 gear is greater than the 4 gear.(6)Under the two operating conditions,the maximum average temperature of the friction pair does not reach the highest temperature that the material can bear,so the wet dual clutch can meet the requirements of use.