Research on the Wet Clutch Engagement Torque

2014 ◽  
Author(s):  
Yingying Zhang ◽  
Changle Xiang
Keyword(s):  
Rough Surface ◽  
Automatic Transmission ◽  
Squeeze Film ◽  
Real Contact Area ◽  
Asperity Contact ◽  
Time Flow ◽  
Clutch Engagement ◽  
Wet Clutch ◽  
Lubrication Oil ◽  
Engagement Process

The driving performance of the vehicle with automatic transmission is influenced by the performance of the wet clutch directly. But at present it is still a challenge to build a reliable predictable model for the torque of the engagement process of the wet clutch. Focusing on the wet clutch of vehicle, this paper starts from mechanism analysis, and a modified Reynolds equation with the consideration of the centrifugal force of the squeeze-film is established. In the model, we can consider the speeds of the friction and separator plates independently. At the same time, flow factors have been used to research the impacts of rough surface on the flow of the lubrication oil. In the three-dimensional solution domain, the circumferential pressure gradient of lubrication oil is considered. The model is solved with the finite volume method. The simulation of the torque of the asperity contact calculates the real contact area changed with the engagement process, and the microscopic texture direction of rough surface is considered. Subsequently, the squeeze-film flow model is combined with the asperity contact model to create an integrated clutch engagement model. Finally, the influence of applied force, viscosity of lubrication oil, friction material, the depth of grooves and the width of the grooves are investigated. Based on the comparison with the experimental data, the performance of the proposed model is found satisfactory. Because in this model more detail properties of material and geometric features of the friction plate are include, the wet clutch model developed in this research can become a baseline model for the prediction of the engagement behavior of a real wet clutch. The present model may become an efficient alternative to laboratory testing and lead to designs that can not be envisioned by other approaches.

Modeling and experimental research on engaging characteristics of wet clutch

2019 ◽  
Vol 71 (1) ◽  
pp. 94-101 ◽  
Author(s):  
Yanzhong Wang ◽  
Yuan Li ◽  
Yang Liu ◽  
Wei Zhang
Keyword(s):  
Contact Surface ◽  
Hydrodynamic Lubrication ◽  
Load Capacity ◽  
Lubricating Oil ◽  
Centrifugal Effect ◽  
Element Analysis ◽  
Content Type ◽  
Clutch Engagement ◽  
Wet Clutch ◽  
Engagement Process

PurposeTo gain in-depth understandings of engaging characteristics, the purpose of this paper is to improve the model of wet clutches to predict the transmitted torque during the engagement process.Design/methodology/approachThe model of wet clutch during the engagement process took main factors into account, such as the centrifugal effect of lubricant, permeability of friction material, slippage factor of lubricant on contact surface and roughness of contact surface. Reynolds’ equation was derived to describe the hydrodynamic lubrication characteristics of lubricant film between the friction plate and the separated plate, and an elastic-plastic model of the rough surfaces contact based on the finite element analysis was used to indicate the loading force and friction torque of the contact surface.FindingsThe dynamic characteristics of wet clutch engagement time, relative speed, hydrodynamic lubrication of lubricating oil, rough surface contact load capacity and transfer torque can be obtained by the wet clutch engagement model. And the influence of the groove shape and depth on the engaging characteristics is also analyzed.Originality/valueThe mathematical model of the wet clutch during the engagement process can be used to predict the engaging characteristics of the wet clutch which could be useful to the design of the wet clutch.

scholarly journals Influence of the Lubrication Oil Temperature on the Disengaging Dynamic Characteristics of a Cu-Based Wet Multi-Disc Clutch

2021 ◽  
Vol 11 (23) ◽  
pp. 11299
Author(s):  
Liangjie Zheng ◽  
Biao Ma ◽  
Man Chen ◽  
Liang Yu ◽  
Qian Wang
Keyword(s):  
Dynamic Characteristics ◽  
Hydrodynamic Lubrication ◽  
Friction Pair ◽  
Automatic Transmission ◽  
Friction Torque ◽  
Asperity Contact ◽  
Uniformity Coefficient ◽  
Lubrication Oil ◽  
The Impact ◽  
First Time

Clutch disengaging dynamic characteristics, including the disengaging duration and the variations of friction pair gaps and friction torque, are crucial to the shifting control of an automatic transmission. In the present paper, the influence of lubrication oil (ATF) temperature on disengaging dynamic characteristics is investigated through a comprehensive numerical model for the clutch disengaging process, which considers the hydrodynamic lubrication, the asperity contact, the heat transfer, the spline resistance, and the impact between the piston and clutch hub. Moreover, the non-uniformity coefficient (NUC) is proposed to characterize the disengaging uniformity of friction pairs. As the ATF temperature increases from 60 °C to 140 °C, the clutch disengaging duration shortens remarkably (shortened by 55.1%); besides, the NUC sees a decreasing trend before a slight increase. When the ATF temperature is 80 °C, the distribution of friction pair gaps is most uniform. During the disengaging process, the increase of ATF temperature not only accelerates the change of the lubrication status between friction pairs but also contributes to the decrease of contact torque and hydrodynamic torque. This research demonstrates for the first time, evidence for clutch disengaging dynamic characteristics with the consideration of ATF temperature.

scholarly journals Optimal control for jitter suppression of clutch engagement in upshift process of electric vehicles

2016 ◽  
Vol 8 (12) ◽  
pp. 168781401667484
Author(s):  
Junqiu Li ◽  
Yihe Wang ◽  
Yizheng Wang
Keyword(s):  
Optimal Control ◽  
Dynamic Model ◽  
Automatic Transmission ◽  
Friction Torque ◽  
Dynamic Responses ◽  
Lumped Mass ◽  
Virtual Displacement ◽  
Motor Torque ◽  
Clutch Engagement ◽  
Engagement Process

In the shift process of large-order automatic transmission, jitter phenomenon is common in clutch engagement process, which greatly affects the ride comfort of the vehicle. In this article, the jitter dynamic model of clutch engagement process was established with lumped mass method and virtual displacement principle. Specific to clutch engagement stage, the optimal control of the coordination between driving motor and wet clutch was studied. In accordance with the jitter dynamic model, the state–space equation with controlling variables of motor torque and clutch friction torque was established. In this optimization problem, the torsion angle, torsion angular velocity, and shift jerk are selected as optimization targets. Utilizing the linear quadratic optimal control theory, the optimal trajectory of motor torque and clutch friction torque was obtained. Aiming at the dynamic responses in clutch engagement process, the optimal control in different conditions of weight coefficients, initial torsion angles, and resistance torques was studied. Results showed that the optimal control strategy could obviously reduce the jitter; in addition, the weight coefficient should be determined according to actual situation reasonably.

Numerical Simulation of Engagement of Paper Based Wet Clutch Facing

1994 ◽  
Vol 116 (2) ◽  
pp. 232-237 ◽  
Author(s):  
Shinichi Natsumeda ◽  
Tatsuro Miyoshi
Keyword(s):  
Hydrodynamic Lubrication ◽  
Compressive Strain ◽  
Viscosity Reduction ◽  
Frictional Heat ◽  
Asperity Contact ◽  
Wet Clutch ◽  
Engagement Process ◽  
Torque Curve ◽  
The Many ◽  
Made In

Theoretical analysis was carried out on the engagement process of a paper based wet clutch. The annular multidisk clutch in a SAE#2 tester was chosen as an example. The average flow model on partial hydrodynamic lubrication proposed by Patir and Cheng was employed for the analysis of squeeze motion taking the permeability, the compressive strain, and the asperity contact of paper facing into account. Simultaneously, the equations of heat conduction were solved to calculate the viscosity reduction due to frictional heat generation. The theoretical torque curve agreed qualitatively with the experimental one in spite of the many assumptions made in this analysis.

Optimizing the Smoothness and Temperatures of a Wet Clutch Engagement Through Control of the Normal Force and Drive Torque

1999 ◽  
Vol 122 (1) ◽  
pp. 119-123 ◽  
Author(s):  
Mikael Holgerson
Keyword(s):  
Temperature Rise ◽  
Normal Force ◽  
Dynamic Performance ◽  
Automatic Transmission ◽  
Test Rig ◽  
Friction Characteristics ◽  
Drive Torque ◽  
Clutch Engagement ◽  
Wet Clutch ◽  
Transmission Gear

Automatic transmission gear shifts are handled by wet clutches, which determine the smoothness. The clutch face temperatures during the engagements are often an important parameter for the total clutch life. A wet clutch test rig has been used to evaluate how a wet clutch engagement can be improved in terms of smoothness and temperature. This was performed with control based upon knowledge about friction characteristics and dynamic performance. The parameters used for control were the drive torque and the normal force on the clutch. By drive torque shut-off and reduced normal force the torque variations were greatly reduced and the temperature rise was decreased by 37%. [S0742-4787(00)01601-5]

Hybrid Neural Network for Modeling Automotive Clutches

1999 ◽  
Author(s):  
V. Parvataneni ◽  
M. Cao ◽  
K. W. Wang ◽  
Y. Fujii ◽  
W. Tobler
Keyword(s):  
Neural Network ◽  
Hybrid Model ◽  
Hybrid Network ◽  
Hybrid Neural Network ◽  
Physical Knowledge ◽  
The Neural Network ◽  
Clutch Engagement ◽  
Wet Clutch ◽  
Engagement Process ◽  
Artificial Neural Network Ann

Abstract In this paper, artificial neural network (ANN) based models to capture the dynamic engagement torque of a wet clutch system are developed and analyzed. A two-layer recurrent ANN with output feedback is chosen as the baseline architecture since its simplicity allows easy implementation and efficient execution. Although this model exhibits good performance in capturing the overall mean level of the engagement torque as a function of time, it is unable to predict some of the important clutch dynamics behaviors. To improve the performance, additional neurons that represent the first principles of the clutch engagement process are incorporated into the neural network model. In other words, a hybrid model in which physical knowledge is implicitly embedded within the ANN architecture is derived. This hybrid model is trained and tested with experimental data. The results show that the performance of the hybrid network is much superior to that of the baseline ANN. It can successfully capture not only the trends, but also the detailed characteristics of the clutch engagement torque as a function of time.

Thermal and Dynamic Characterization of Wet Clutch Engagement With Provision for Drive Torque

2000 ◽  
Vol 123 (2) ◽  
pp. 313-323 ◽  
Author(s):  
M. Mansouri ◽  
M. Holgerson ◽  
M. M. Khonsari ◽  
W. Aung
Keyword(s):  
Thermal Stresses ◽  
Automatic Transmission ◽  
Thermal Characteristics ◽  
Element Model ◽  
Large Temperature ◽  
Drive Torque ◽  
Lubrication Regimes ◽  
Clutch Engagement ◽  
Wide Range ◽  
Wet Clutch

Wet clutches that handle the gearshifts in automatic transmission undergo severe thermal stresses due to the occurrence of large temperature gradients during engagement. To accurately design wet clutches, better models to simulate the engagement process are needed. This work presents a finite element model for simulating wet clutch engagements. The total friction coefficient was used to describe the different lubrication regimes that a wet clutch engagement undergoes. The model also includes provision for drive torque that realistically simulates the engine torque of a car. The results of the simulations are successfully verified by comparison with laboratory experiments on a testrig specially designed to accommodate the drive torque, covering a wide range of typical engagements. Excellent agreement between experiment and simulations is reported in terms of both the dynamics of the engagement and the thermal characteristics. The results are indicative of the utility of the model as a useful engineering tool.

Parametric analysis of wear factors of a wet clutch friction material with different groove patterns

2017 ◽  
Vol 231 (8) ◽  
pp. 1056-1067 ◽  
Author(s):  
M Li ◽  
MM Khonsari ◽  
DMC McCarthy ◽  
Joakim Lundin
Keyword(s):  
Temperature Field ◽  
Material Properties ◽  
Parametric Analysis ◽  
Wear Test ◽  
Friction Material ◽  
Asperity Contact ◽  
Wet Clutch ◽  
Engagement Process ◽  
Insight Into ◽  
Friction Lining

The experimentally observed, two-stage wear in the wet clutch friction material is directly related to temperature and engagement load. To gain insight into the durability of the friction lining, an extensive parametric analysis of the factors is performed that takes into account different groove patterns (waffle shape, radial, and spiral), internal structure and material properties. The temperature field is predicted using a thermohydrodynamic analysis with the consideration of the asperity contact stress during the engagement process. The results should be useful to facilitate the industrial design of friction lining by avoiding costly wear test.

scholarly journals Response Characteristics of Dynamic Torque for Wet Clutch Engagement: A Numerical and Experimental Study

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Zhigang Zhang ◽  
Ling Zou ◽  
Hang Liu ◽  
Jin Feng ◽  
Zhige Chen
Keyword(s):  
Elastic Modulus ◽  
Applied Pressure ◽  
Asperity Contact ◽  
Oil Film ◽  
Response Characteristics ◽  
Clutch Engagement ◽  
Torque Response ◽  
Wet Clutch ◽  
Friction Lining ◽  
Lubricant Viscosity

To determine the factors affecting the dynamic transmitted torque response characteristics of the wet clutch, the oil film pressure, the asperity contact pressure, the applied pressure, and the dynamic transmitted torque model were established, using the fourth-order Runge–Kutta numerical method to couple the oil film thickness and the speed difference to obtain the change curve of the joint pressure and the transmitted torque. The established model was used to study the influence of the pressure hysteresis time, lubricant viscosity, friction lining permeability, friction pair equivalent elastic modulus, and surface combined roughness RMS on the dynamic transmitted torque response during the wet clutch engagement. The results indicate that the longer the pressure hysteresis time, the smaller the permeability of the friction lining, the smaller the equivalent elastic modulus, the greater surface combined roughness RMS, the more delayed the response of the transmitted torque, and the smaller the level of jerk of the wet clutch engagement. Also, the lower the lubricant viscosity, the greater the permeability of the friction lining, and the smaller the equivalent elastic modulus is and the greater surface combined roughness RMS is, the more sensitive the transmitted torque response is to pressure response changes.

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