Measuring tappet rotation in a valvetrain rig when lubricated in a fully formulated oil containing MoDTC-type friction modifier
Measuring tappet rotation in a valvetrain rig when lubricated in a fully formulated oil containing MoDTC-type friction modifier
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DOI：
10.1016/j.triboint.2018.01.061
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发表时间：
2018-05-01
影响因子：
6.2
通讯作者：
Neville, Anne
中科院分区：
文献类型：
--
作者：
Al-Jeboori, Yasir;Kosarieh, Shahriar;Neville, Anne
在直动式气门机构配置中，挺杆旋转在改善润滑、减少磨损和摩擦方面发挥着关键作用。然而，据作者所知，没有研究调查在不同涂层、挺杆厚度和二烷基二硫代氨基甲酸钼 (MoDTC) 配方的影响下挺杆的旋转情况，最近有报道称，二烷基二硫代氨基甲酸钼 (MoDTC) 不利于类金刚石碳 (DLC) 磨损。在这项工作中，开发了一种测量挺杆旋转的新技术。使用与分裂极铁氧体圆盘磁体耦合的巨磁阻（GMR）传感器。传感器安装在非常靠近挺杆/铲斗的位置，而磁铁安装在挺杆的下侧。使用涂有磷酸锰 (MnPO4) 和类金刚石碳 (DLC) 涂层的标准生产钢挺杆进行实验。一般来说，结果表明挺杆旋转很大程度上取决于油配方、间隙、速度/温度和涂层的表面粗糙度。 MoDTC 促进了两种涂层下挺杆的旋转。此外，与 MnPO4 刀片相比，DLC 刀片的挺杆旋转有所增加。然而，无论涂层类型如何，最厚的挺杆表现出最高的旋转。
In a direct acting valve train configuration, tappet rotation plays a key role in improving lubrication, reducing wear and friction. However, to the best of the authors' knowledge, no studies were found to investigate the rotation off tappet under the effect of different coatings, thicknesses of tappets and formulations with Molybdenum Dialkyl Dithiocarbamate (MoDTC) which has been recently reported to be detrimental to Diamond-Like Carbon (DLC) wear. In this work, a new technique of measuring tappet rotation has been developed. A giant magneto resistance (GMR) sensor coupled with a split pole ferrite disk magnet was used. The sensor was installed very close to the tappet/bucket while the magnet was mounted into the underside of the tappet. Experiments were performed using standard production steel tappets coated with Mn-phosphate (MnPO4) and diamond-like carbon (DLC) coatings. In general, results showed that the tappet rotation is strongly dependant on oil formulation, clearance, speed/temperature, and surface roughness of the coating. MoDTC promoted the rotation of the tappet under both coatings. In addition, DLC inserts showed an increase in tappet rotation as compared to MnPO4 inserts. Nevertheless, regardless of the type of coating, the thickest tappets showed the highest rotation.