Development Of Test System For Heat Transfer Parameters Of Cylinder Liner

Pure aluminum engines are widely used in the automotive industry for their light weight and thus reduced fuel consumption.However,the cylinder liner of the pure aluminum engine cannot be completely replaced by aluminum alloy,because the wear resistance and strength of aluminum are worse than that of cast iron,so a new technology has been developed.The cylinder bore of the pure aluminum engine is inlaid with cast iron cylinder liner,which not only reduces the weight of the car,but also meets the requirements of the wear resistance of the engine at high speed.One of the key points of this technology is to ensure the tight integration of cast iron and aluminum alloy cylinders.A common method to solve this problem is to form a "mushroom head" on the surface of the cylinder liner,thereby increasing the contact area between the aluminum liquid and the outer surface of the cylinder liner.The design of the "mushroom head" shape and the design of the cylinder liner thickness have different heat transfer characteristics.As one of the important performances of cylinder liners,heat transfer characteristics are generally measured by thermal conductivity,which is an important parameter for designing “mushroom head” type cylinder liners.This paper mainly studies the basic theoretical knowledge of material heat transfer,and reveals that the heat conduction of objects is generally divided into steady-state heat transfer and non-steady heat transfer.This paper introduces several commonly used thermal conductivity measurement methods and their principles,analyzes and compares their characteristics and adaptability range,and proposes a heat transfer model for measuring the thermal conductivity of cylinder liners.Based on this,a test system for heat transfer performance of cylinder liners is developed.The system includes experimental platform and fixture structure design,heating rod and heating power control circuit and temperature measurement system design.Finally,the system is tested and verified by standard test.The system can qualitatively measure the thermal conductivity of the cylinder liner,and provide reference for the design of the "mushroom head" shape and the thickness ratio of the cylinder sleeve.