【作者】 张世锋；

【导师】 徐久军；

【作者基本信息】 大连海事大学 ， 轮机工程， 2016， 博士

【摘要】 摩擦副不同的润滑状态必然导致不同的摩擦功耗和磨损,如要保证内燃机的可靠性与动力性,则首先要确保其摩擦副处于最佳的润滑状态,研究润滑状态及转化特性的关键问题之一是实现润滑状态的实时测量,其中确定由流体润滑向混合润滑和边界润滑转化的特征尤其重要。针对这一目标,首先进行了测试方法的选择,然后对摩擦状态的特性进行了分析,最后对缸套-活塞环摩擦状态转化进行了实时测量与验证。接触电阻法在定性分析润滑状态时是一种行之有效的测试方法,而且电路简单不需要昂贵的测试设备,但在定量地反映膜厚上存在困难。为了克服这一缺陷,利用自制的旋转式点接触摩擦磨损实验机,通过实验与理论分析相结合的方法,建立了点接触膜厚比与接触电阻之间明确的对应关系,这样就利用实时测得的电阻值确定了点接触的润滑状态。缸套-活塞环在压缩、燃烧、膨胀和排气各冲程中,会经历流体动压润滑、混合润滑、边界润滑等多种摩擦状态。为了确定缸套-活塞环的实时润滑状态,基于点接触膜厚比与接触电阻之间的对应关系,开展了电阻测量方法的缸套-活塞环润滑状态测试实验研究。该部分实验是在自制的缸套-活塞环往复式实验台上完成的,通过温度、载荷分级实验验证了接触电阻法判定缸套-活塞环摩擦副润滑状态的实用性与可靠性。传统的观点是把润滑状态分为流体动压润滑、弹流润滑、混合润滑、边界润滑及干摩擦等几个状态。近年来,有些学者提出在弹流润滑和边界润滑之间还存在着薄膜润滑,薄膜润滑和弹流润滑是两种不同的润滑状态,其润滑机理不同,所采用的理论基础也相应的差异较大,为了确定薄膜润滑状态的特性,在弹流计算的基础上,采用整体平均的等效黏度的修正公式,建立了运算速度快、结果更准确的计算模型,用于描述摩擦副的薄膜润滑状态,从而确定其润滑特性。综合考虑润滑表面综合粗糙度、缸套圆周方向的形变、润滑油的粘度等因素,使用整体平均的等效黏度的修正公式综合分析缸套-活塞环润滑系统润滑的性能,计算最小油膜厚度、压力分布情况、摩擦力等,建立缸套-活塞环三维瞬态润滑数学模型,从而为缸套-活塞环的摩擦状态分析提供了依据。更多还原

【Abstract】 The different lubrication state of friction pair will inevitably lead to different friction power consumption and wear. To ensure the reliability and power of the internal combustion engine, it is first to ensure that the friction pair in the best lubrication state. A key problem of lubrication state and transformation characteristics is to achieve real-time measurement of lubrication state. Especially, determining the transformation features from fluid lubrication state to mix lubrication state and boundary state is important.For this aim, the selection of the test method is firstly carried out, and then the characteristics of the friction state are analyzed. Finally, the friction state of cylinder liner piston ring is measured and verified in real time.The contact resistance method is an effective test method at the lubrication state analysis, the circuit is simple and it does not require expensive test equipment, but there are difficulties in reflect the film thickness quantitatively. By using self-made rotating point contact friction and wear tester, with combined experimental and theoretical analysis method, the relation between the contact point film thickness ratio and the contact resistance is established, so as to determine the lubrication state of point contact.Friction power loss caused by cylinder -piston ring is an important part of internal combustion engine friction power loss; it is a key component which effected internal combustion engine reliability, economy and power. In compression, combustion, expansion and exhaust strokes, Cylinder-piston ring friction pair will experience hydrodynamic lubrication, mixed lubrication, boundary lubrication friction and other states. In order to investigate the real-time lubricant state of Cylinder-piston ring, experimental study was carried out based on resistance measurement test method. This part of the experiment is completed with homemade reciprocating cylinder-piston ring experimental table. The practicability and reliability of contact resistance method determined the cylinder -piston ring lubrication states are verified through the temperature, load classification experiments.According to the traditional view, the lubrication state divided into fluid dynamic pressure lubrication, elastohydro-dynamic lubrication, the mixed lubrication and boundary lubrication. In recent years, some scholars believe that there is a separate lubricate state between elastohydro-dynamic lubrication and boundary lubrication, which is thin film lubrication.EHL lubrication and thin film lubrication are two different lubrication states. Lubrication mechanism is different and the adopted theoretical basis is also quite different. To determine the thin film lubricant state characteristics, on the basis of the EHL calculation, adapted the modified formula for the overall average equivalent viscosity, a faster and more accurate computational model is established to simulate thin film lubrication state of friction pair.Considered comprehensive lubricating surface roughness, the deformation in the circumferential direction of the liner, the viscosity of lubricating oil and other factors, a three-dimensional transient lubrication mathematical model for the cylinder-piston ring is established. The performance of cylinder-piston ring lubrication system is comprehensive studied, the minimum film thickness, the distribution of pressure, friction, etc., are calculated, which provides a basis for engineering design of cylinder liner and piston ring friction state.更多还原