1 前言随着汽车、拖拉机和工程机械制造工业的发展,内燃机朝着结构日趋紧凑、升功率日益增大、单位面积承受载荷不断增强、热负荷不断提高等方向发展。由此带来内燃机各种运动部件的摩擦、磨损增加和润滑油温度升高等问题,使润滑条件更加苛刻。故润滑已成为提高内燃机可靠性和耐久性的一个非常关键的问题。润滑不良的发动机,其摩擦损失和零部件的磨损都会增大,并可能造成操作事故。而摩擦副的良好润滑对减少摩擦损失、提高机械效率、保证发动机经济、可靠地 1 Foreword With the development of automobile, tractor and engineering machinery manufacturing industry, internal combustion engines are developing in the direction of increasingly compact structure, rising power, unit load carrying capacity and increasing heat load. As a result, friction, wear, and temperature increase of various moving parts of the internal combustion engine lead to more severe lubrication conditions. Therefore, lubrication has become a very crucial issue for improving the reliability and durability of internal combustion engines. Poor lubrication of the engine, the friction loss and wear and tear components will increase, and may cause operational accidents. The friction pair of good lubrication to reduce friction loss, improve mechanical efficiency, to ensure that the engine economy, reliable