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Optimum Design of an Assist Mechanism for a Motorcycle Multi-Plate Clutch

EXEDY Corporation-Misaki Minoha, Koji Yoneyama, Ryoichi Imai, Hidenori Kitazawa, Osamu Mano, Shinya Miyagawa
  • Technical Paper
  • 2019-32-0523
To be published on 2020-01-24 by Society of Automotive Engineers of Japan in Japan
In recent years, the popularity of leisure-motivated large motorcycles has increased as the demand for high-added value motorcycles is growing. Therefore, large motorcycle engines have become more powerful. Due to this trend, the capacity of the clutch is also required to increase. Contrary to the demand for high engine power and high clutch capacity, reductions in weight, space, operational load, and shock at deceleration are permanent issues of motorcycle development. The consideration of all these issues are required during development of a clutch for large motorcycles. Considering the above issues, a clutch with an assist cam and slipper cam mechanism is effective for cost and performance. The assist cam mechanism allows the clutch to have a larger transmittable torque without an increase of the clutch lever load. The slipper cam mechanism can automatically reduce the transmitted torque when shock from sudden engine braking happens during downshifting. Therefore, the installation of the clutch with cam mechanism on large motorcycles is becoming standard in the motorcycle industry. Regarding smaller motorcycles, the reduction of the number of clutch…
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Optimized Wet Clutch Design

Endurance Technologies Ltd., India-Nitin Bhone, Sachin Thakare, Ashutosh Jahagirdar
  • Technical Paper
  • 2019-32-0553
To be published on 2020-01-24 by Society of Automotive Engineers of Japan in Japan
Multi-plate wet clutches used in motorbikes transmit the torque by friction under pressure between driving and driven Plates. The life & performance of the clutch for the friction material used, depends on amount of energy generated during clutch slip, amount & uniformity of heat dissipation amongst the plates and surface texture of mating surfaces.Above parameters if not properly considered during design stage may lead to higher temperature of rubbing surfaces. Higher temperature further reduces the friction coefficient and increases the wear rate of friction material leading ultimately to lower torque capacity of clutch. The temperature rise in a wet clutch is the balance between amount of heat generated and the amount of heat dissipated by oil flowing through clutch. The maximum amount of oil is limited by the requirement of clutch drag torque, Which decides the quality of neutral finding and gear shift feel on vehicle.Further, if roughness of rubbing surfaces is not controlled in mass production, it leads to fast wear of friction material during initial operating cycles. The rate of wear is faster…
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A methodology for a thermal-displacement simulation applied on clutches by finite element analysis

Schaeffler Brasil Ltda.-Joed Henrique Paes, Gustavo dos Santos Gioria
  • Technical Paper
  • 2019-36-0129
Published 2020-01-13 by SAE International in United States
Clutches are mechanisms used for coupling between shafts in order to transmit torque from one to the other. This coupling is made mechanically by friction between the parts with a high friction intermediate material. In this process, the slippage between the parts becomes a source of heat that makes the system temperature to raise up to high values. Under high temperature, the capacity of torque transmission of the clutch can be reduced by the variation of the effective contact diameter, once the contact region of friction change as the temperature is rising. This is caused by the thermal-displacement effect induced by the friction. The torque capacity also can be affected by the friction coefficient that varies with the temperature. Therefore, in order to design an optimized system, it is necessary an analysis of the parts and materials under the influence of temperature changing. This work proposes a simulation methodology for the evaluation of tensions and deformations influenced by the friction heat generation through a test of 15 uniform load cycles of energy by 30 kJ…
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Prediction of Friction Durability in Off-Road Applications Based on Mechanistic Understanding of the Effects of Fluids and Surfaces on Clutch Friction

Afton Chemical Corporation-Mark Devlin, Atanu Adhvaryu
Komatsu Ltd.-Shinpei Kariwa, Toshiharu Abekawa
  • Technical Paper
  • 2019-01-2339
Published 2019-12-19 by SAE International in United States
After new transmission lubricants are developed there is an extensive validation program where friction durability testing is performed on multiple clutch materials. Each durability test can run for long terms and the entire validation program can take much longer terms. A well designed lubricant and friction material will deliver the necessary friction control for construction equipment to operate at optimum level. A mechanistic construct has been evaluated to calculate friction durability in clutch systems based on fluid and surface tribological properties. Fluid properties include both boundary frictional and rheological effects. Surface properties include elastic modulus, surface roughness, asperity density and asperity tip radius. Using this mechanistic construct friction durability has been predicted. In the past, researchers in the field have often associated lubricant induced glazing of the friction material surface as the cause of the loss of friction control in clutch systems. In the current study, results show that wear is also a dominant cause of friction loss. In short clutch friction tests the rate of change in surface properties and fluid properties have been…
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Advanced Bench Test Methodology for Generating Wet Clutch Torque Transfer Functions for Enhanced Drivability Simulations

F.C.C. CO., LTD.-Takahiro Tsuchiya, Masatoshi Miyagawa, Shinji Nakamura, Matthew Wendel, Hiroya Miyoshi
Ford Motor Company-Hiral Haria, Yuji Fujii, Gregory M. Pietron, Anna Sun
  • Technical Paper
  • 2019-01-2340
Published 2019-12-19 by SAE International in United States
A wet clutch continues to play a critical role for step-ratio automatic transmissions and finds new utilities in hybrid and electrified propulsion systems. A torque transfer function is often employed in practice for sophisticated clutch slip controls. It provides a simple, yet practical framework to represent clutch torque as a function of actuator force. An accurate transfer function is also increasingly desired in today's vehicle design process to enable upfront assessment of clutch controls through simulations. The most common approach is based on Coulomb's linear friction model, where the coefficients are adaptively identified based on vehicle data. However, it is generally difficult to tune Coulomb's model for hydrodynamic behaviors even if the reference vehicle data are available. It also remains a challenge to produce in-vehicle clutch behaviors on a component test bench to determine realistic transfer function before prototype vehicles are built. SAE#2 test procedure is the industry standard for evaluating clutch frictional behaviors. It is a viable tool for durability assessment, but not designed to characterize hydrodynamic behaviors for clutch controls. This research focuses…
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Equivalent Radiated Power driven optimization for driveline housings using simulation tools to cut-down the project time

VE Commercial Vehicles, Ltd.-Suresh Kumar Kandreegula, Hemant Nishad, Dheeraj Singh, Kunal Kamal
  • Technical Paper
  • 2019-28-2533
Published 2019-11-21 by SAE International in United States
In the field of Automotive industry, being competitive makes you succeed. Industry is moving towards advancement day by day. New technologies to improve fuel efficiency, crash resistance, vehicle noise levels have been trending. At VECV, we have traditionally worked on CAE of driveline housings (clutch housing & transmission housing) based on static, dynamic and transient loadings. Currently, weight optimization technique depends on the structural and dynamic loading conditions, but do not consider acoustic concerns. Powertrain housings are highly prone to vibrations and leads to high level of noise. Noise has been constant issue in the casting components associated to driveline. There have been lot of research going on to reduce the level of noise and vibrations in the vehicle driveline, which ultimately leads to fuel efficiency and ergonomic benefits. Low noise generation can also lead to saving of lot of resources deployed to dampen the noises. In order to capture the acoustic responses of the system and to improve the design based on acoustic responses, a comprehensive analysis of newly developed driveline housings (clutch housing…
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Automatic Transmissions - Schematic Diagrams

Automatic Transmission and Transaxle Committee
  • Ground Vehicle Standard
  • J647_201911
  • Current
Published 2019-11-19 by SAE International in United States
The following schematic diagrams reflect various methods of illustrating automotive transmission arrangements. These have been developed to facilitate a clear understanding of the functional interrelations of the gearing, clutches, hydrodynamic drive unit, and other transmission components. Two variations of transmission diagrams are used: in neutral (clutches not applied), and in gear. For illustrative purposes, some typical transmissions are shown.
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Analysis of a Coordinated Engine-Start Control Strategy for P2 Hybrid Electric Vehicle

Tianjin University-Chen Zhao, Bingfeng Zu, Yuliang Xu, Zhen Wang, Lina Liu, Jianwei Zhou
Weichai Power Co Ltd-Guangxing Zhao
Published 2019-11-04 by SAE International in United States
P2 hybrid electric vehicle is the single-motor parallel configuration integrating with an engine disconnect clutch (EDC) between the engine and the motor. The key point with P2 hybrid electric vehicle is to start the engine utilizing the single driving motor while still propelling the vehicle, which requires an appropriate engine-start control strategy and a high mechanical performance of EDC. Since the space for EDC is limited, EDC torque response is difficult to follow the torque command, which complicates the issue of precisely controlling the clutch. Consequently, methods proposed in massive papers are inappropriate for current EDC of target vehicle. Considering that slip control of shifting clutch also contributes to reducing impact of engine start assisted by EDC, a detailed engine-start control strategy was proposed to simplify the control of EDC for being applied to actual target vehicle. Furthermore, the control strategy proposed in this paper was utilized to realize driving mode transformation from motor-only to engine-only. In this paper, a detailed hybrid electric vehicle simulation model was established with the consideration of dynamic characteristics of…
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Design of a Novel Electro-Pneumatic Gear Shift System for a Sequential Gearbox

Vellore Institute of Technology-Jeevesh Jain, Vaibhav Mittal, Dore Ranganath Srinivasa Raghuraman, Shivam Singh Rathore, Sumit Nilesh Vadodaria
Published 2019-10-11 by SAE International in United States
This paper describes the design of a novel pneumatic gear shifting system to replace the existing gear stick manual shifting system for ease of the driver while shifting gears. The aim of this work is to have a semi-automatic shifting (pneumatic shifting) removing the need for the driver clutch operation. The system consists of a solenoid valve, CO2 gas-pressurized cylinder, double-acting cylinder, and single-acting cylinder. On basis of the signal received the gear needs to be changed, the shifter opens or closes a magnetic valve assembly. The solenoid valve allows the compressed air into the piston that comes from a pressurized cylinder, in order to create the effect of shifting gears. The pedal shifter and buttons are used to shift the gears. The pedal shifter was designed by using a 3-D printing technique using PLA material. The microcontroller used is ATMEGA-328 in this system. There are three switches, one for upshift, downshift, and clutch respectively. An algorithm has been created in a microcontroller for a sequential gearbox of CBR 600RR. The system has been so…
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Fuel Efficiency Improvement in Automatic Transmissions by Lockup Slip Methodology

Mahindra & Mahindra, Ltd.-Arun Sukumar
Published 2019-10-11 by SAE International in United States
Increasing of automatic transmissions in passenger cars is based on pleasure of driving, smooth acceleration and easy operation makes the customer satisfaction. Challenges beyond 2020 is BS VI emission norms in India - a very tough goals on CO2& NOx reduction in Gasoline & Diesel vehicles. But its setback in lower fuel economy.To support & enhance fuel economy in Automatic transmissions as part of drivetrain technologies, this article discusses about the power losses in torque converters and experiments on the actual Automatic transmission (AT) vehicle on-road to understand the real city driving behavior in the aspects of gear utilization & gas pedal utilization throughout the entire traffic conditions. With that data research, slip area and slipping conditions is determined & clutch slip control is enabled at area in torque converter by ensuring that NVH parameters are not affected.The addition of the Lock-up Slip system add value in terms of “Joy of Driving” by providing a 2-3% improvement in fuel economy over the previous one.
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