The SAE MOBILUS platform will continue to be accessible and populated with high quality technical content during the coronavirus (COVID-19) pandemic. x

Your Selections

Shen, Ye
Show Only


File Formats

Content Types








   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Theoretical and Experimental Investigation on Power Loss of Vehicle Transmission Synchronizers with Spray Lubrication

SAE International Journal of Advances and Current Practices in Mobility

TU Darmstadt-Zhihong Liu, Ye Shen, Stephan Rinderknecht
  • Journal Article
  • 2019-01-0028
Published 2019-01-15 by SAE International in United States
Besides optimal engine systems, high-efficiency vehicle transmissions are generally also required to improve fuel economy in automotive applications. For the energy loss analysis in transmissions, most research focused on the major mechanical components, such as gears, bearings and seals, while the other mechanical losses, like synchronizer losses, were usually not considered. With increasing number of synchronizers in modern transmissions, a recent study indicates that the power loss analysis of synchronizers should also be developed and appended for a more accurate investigation on overall power losses in transmissions. The function of synchronizer is to equalize the different rotational speeds of shafts and gear wheels by frictional torques, for which the synchronizer must be cooled and lubricated in order to enhance the service life. With the supplement of lubricants, fluid friction is generated due to the differential speed, when the synchronizer is in neutral position. This fluid friction can be principally regarded as load-independent synchronizer power loss. In this paper, fluid states and fluid dynamics in synchronizers with spray lubrication are analyzed analogously to multiple-plate clutches. Based…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Modelling of Power Losses of Transmission Synchronizers in Neutral Position

IMS,Technische Universität Darmstadt-Ye Shen, Zhihong Liu
TU Darmstadt-Stephan Rinderknecht
Published 2018-04-03 by SAE International in United States
Developing an energy-efficient powertrain system is a solution for environment-friendly vehicles. Furthermore, it also enhances the performance of vehicles. In powertrain system, transmission plays an important role in terms of vehicle dynamic performance and energy consumption. Therefore, a lot of researches have been conducted on modelling power losses inside the transmission. Basically, the power losses in transmission consist of bearing losses, drag torque losses on gear blank that is immersed in the oil and gear mesh losses due to the sliding frictional force on gear flank. According to some experiments in the latest literatures, power losses of synchronizers cannot be neglected, when its shift sleeve is in neutral position. Principally, power losses of synchronizers in neutral position mainly come from load independent drag torque. The drag torque is generated by the shear torque of lubrication in the gap (or gaps) between synchronizer ring and synchronizer cone, which are rotating at different speed. In this paper, a drag torque model of synchronizer units in neutral position is built up based on mechanism of tribology lubrication. Several…
This content contains downloadable datasets
Annotation ability available