Browse Topic: Clutch components

Items (703)

Impact of torsional vibrations on the strength of clutch dampers.

2025-01-009905/05/2023

The clutch is a mechanical device that engages and disengages power transmission from the engine to the wheels. The damper mechanism integrated into the clutch disc is designed to attenuate the torsional vibrations from the engine. This study investigates the impact of torsional vibrations on the structural durability of a clutch disc damper of the intermediate and light commercial vehicle. The baseline clutch damper's springs experienced excessive deflection angles due to driveline resonance experienced in operation, resulting in the springs hitting the contact surface. This caused the springs to fail due to the high stresses created during operation. A 1D simulation model is utilized to predict the torsional vibration behavior of the vehicle. The driveline's 1D model is created using Amesim software, and the simulated results demonstrate a strong correlation with the actual torsional measurements taken at the vehicle level for the baseline clutch damper. A new clutch damper design

Jagtap, Amol Shivaji, Chollangi, Damodar, PACHPANDE, PRASHANT

Pseudo Transient Torque Converter Clutch Engagement Process Using Fluid-Structure Interaction Simulation

2022-01-078103/29/2022

This investigation utilizes a correlated fluid-structure interaction (FSI) model of the torque converter and clutch assembly to perform a pseudo transient clutch engagement at steady state operating conditions. The pseudo transient condition consists of a series of nine steady state simulations that transition the torque converter clutch from fully released to near full lockup at a constant input torque and output speed representative of a highway cruising speed. The flow and pressured field of the torque converter torus and clutch are solved using a CFD model and then passed along to a transient structural model to determine the torque capacity of the lockup clutch. Bulk property assumptions regarding the friction material, deformation of the clutch plate and deflection of supporting structures were made to simplify the model setup, run time and solution convergence. Telemetry pressure measurements acquired in an operating torque converter under similar operating conditions on a

Beldar, Aniket, Robinette, Darrell, Blough, Jason

Improving the design of automotive air conditioning compressors by predicting the minimum engagement voltage of electromagnetic clutches

2022-01-020603/29/2022

In order to insure passengers comfort, automotive air conditioning compressors are designed to be operational in case of low battery voltage. However, the “minimum engagement voltage” of compressors is mostly driven by designers’ know-how and rely extensively on laboratory tests, which can lead to two issues: Costly design modifications if problems are detected too late in the validation phase and the necessity to perform several design iterations before reaching the desired target. This paper presents the benefit of predicting the minimum engagement voltage where both of these drawbacks can be avoided, leading to a more robust design process. The method was tested on an electromagnetic clutch whose purpose is to engage the compressor when the air conditioning is turned on by passengers. The magnetic field generated by the clutch was estimated using an electromagnetic simulation software. Coil design parameters, materials magnetic properties, clutch assembly geometry and air gaps were

PLUY, Nicolas, Ohk, Changheon

A Time Efficient Thermal and Hydrodynamic Model for Multi Disc Wet Clutches

2022-01-078603/29/2022

Wet Clutches are used in automotive powertrains to enable compact designs and efficient gear shifting. During the slip phase of engagement, significant flash temperatures arise at the friction disc to separator interface as a result of dissipative frictional losses. An important aspect of the design process is to ensure the interface temperature does not exceed the material temperature threshold at which accelerated wear behaviour and/or thermal degradation occurs. During early stages of a design process, it is advantageous to evaluate numerous system and component design iterations exposed to plethora of possible drive cycles. A simulation tool is needed which can determine what are the critical operating conditions that need to be validated for the system performance and durability to be assured. This paper describes a time-efficient multiphysics model developed to predict clutch disc temperatures with a runtime of minutes. It consists of a simplified 1D numerical model of heat

Morris, Samuel Adam, Morris, Nicholas John, Leighton PhD, Michael

Simulation of Dynamic and Thermal stresses on clutch assembly and Study of their effect on clutch pedal effort characteristics

2022-01-031103/29/2022

Single plate dry clutch has to sustain higher thermal stresses combined with different dynamic operating conditions during vehicle usage. With growing population of traffic in cities, temperature sustainability of clutch is affected which is evident from the rise in complaints on clutch from metropolitan cities. Child parts of the clutch cover assembly such as diaphragm spring, straps, etc. should be able to sustain the higher operating temperature without much deterioration in the assembly functional parameters such as release load, clamp load, pressure plate lift. Further, different operating speeds of the engine induces different dynamic stresses in the clutch components, adding into the thermal effect. The effect of critical performance attributes of clutch system is on clutch pedal effort characteristics. The deterioration in the release load of the clutch directly affects the clutch pedal effort characteristics and clutch pedal feel for the driver. The clutch release system

Katarki, Shrirang Sharad, Mohire, Sujit, Tendulkar, Vishveshvar, Deokar, Kiran, Sontakke, Swapnil

Optimum Solution for Reduction of Clutch Pedal Vibration and Groan Noise Observed During Clutch Pedal Actuation

2021-28-016910/01/2021

Abstract In emerging markets like India, manual transmission vehicles are still most preferred & contributes to 85% of passenger vehicle sales due to its cost benefit. However, customer expects good NVH behavior for comfortable driving experience in the vehicle to maneuver effortlessly in the highly congested traffic conditions in India. Clutch & its hydraulic release system in manual transmission of IC engines are the significant components which affects the NVH behavior & maneuverability of the vehicle and the driver comfort significantly. This paper focuses on the clutch pedal vibration & groan noise concern observed during clutch pedal actuation in high power density SUV vehicle developed for Indian market. The vehicle had highly efficient & light weight engine which has high engine axial vibrations. Axial vibrations are caused due to engine firing impulses & crankshaft bending causes flywheel axial movement. This movement in turn leads to vibrations in clutch cover diaphragm

VARUN KUMAR, D, Sathish, PB, Vellandi, Vikraman, M, Sudhan, Vijayarangan, Deepak

A Unique Methodology to Evaluate the Metallic noise concern of a Dual-Mass Flywheel Under Real-World Usage Conditions

2021-28-024910/01/2021

Dual mass flywheel (DMF) is an excellent solution to improve the noise, vibration and harshness (NVH) characteristic of any vehicle by isolating the driveline from the engine torsional vibrations. For the same reason, DMFs are widely used in high power-density diesel and gasoline engines. However, the real-world usage conditions pose a lot of challenges to the robustness of the DMF. In the present work, a new methodology is developed to evaluate the robustness of a DMF capturing the RWUP conditions fitted in a Sports utility vehicle (SUV) with front-wheel drive architecture. During engagement of clutch system, enormous amount of energy is dissipated. To sustain the operating temperature of the clutch system, generated energy is dissipated through conduction & convection. If the temperature of the clutch friction material is not retained, clutch burning & burst failures happens. Ventilation holes are provided on clutch housing to improve convective heat transfer. During rainy season in

S, Kesavprasad, M, Sudhan, Vijayarangan, Deepak, Rai, Vikas

An experimental approach to monitor the clutch thermal condition to increase the clutch life

2021-28-028110/01/2021

One of the top problems that every Indian automobile manufacturer struggles to manage is the clutch early failure less than 30000 Km. This is mainly due to the extreme heating of the friction lining due to the real-world user profile in the Indian market and users inappropriate driving behaviors like Overloading the goods more than the manufacturer’s recommendation, Non recommended attachments and increased wheel size, Thick traffic leading to high level of clutch modulation and Clutch riding while running and launching the vehicle at higher gears. Although many simulation and testing are done during the development phase, above listed real world user profile and customer driving habits are inevitable by any automobile manufacturer. Hence the prime goal of this experimental research is to indicate or alert the user on the clutch thermal condition due to the driving habit and to encourage the user on right driving habits. This objective is met through an stand alone electronic system

M, Sudhan, B, Vasanthan

Necessity of damper for Hydrostatic Transmission (HST) Tractors

2021-26-027809/22/2021

In a modern world, the tractor customer demands are increasing for more comfortable, new technology, fuel efficient and quieter vehicle. The customer’s expectation for NVH refinement often challenges the limitations for tractor designs. For smaller tractors Hydrostatic Transmission (HST) is need due to higher demand for fuel efficiency, lightweight powertrain, and the operation will become easy in the field. With the Hydrostatic Transmission (HST) tractor without damper, there is a technical challenge like withstanding of the sudden impacts from the implements which are connected to PTO during field operations. The NVH behavior in driveline is critical phenomena which can cause the discomfort to end users and structural failure of driveline parts. During gear engagement due to sudden variation in torque the driveline parts are tends to clash each other because of lashes which will create high level of angular acceleration and noise. Practical measurement study has been done to identify

Rajendran, Ashok Kumar, Bagadekar, Vijaykumar, Alavilli, Satya Pavan

Improving the clutch design robustness by Virtual validation to Predict Clutch Energy Dissipation and Temperature in Clutch Housing

2021-26-032909/22/2021

Clutch is a very important component of any vehicle equipped with the manual transmission (MT), automated manual transmission (AMT) or dual-clutch transmission (DCT). During launch of a vehicle(moving from “0” speed), clutch is being slowly engaged by the Driver or TCU(for AMT vehicle) for smooth torque transfer between engine and transmission. The clutch is design to transfer max engine torque with min heat generation. During the clutch engagement, the difference in the input (engine flywheel) and output shaft (clutch disc) speed of clutch called the clutch slipping phase which then leads to a huge amount of energy being dissipated in terms heat due to friction. As a result, clutch surface temperature increase consistently, when the surface temperature cross the threshold limit, the clutch wear out quickly or burns spontaneously. Hence it is crucial to predict the energy dissipation and temperature variation in various components of clutch assembly through virtual simulation. During

Ganesh, Mohan Selvakumar, Chopra, Ujjwal, Kanagaraj, Pothiraj, M, Sudhan

On the Effect of Clutch Dynamic Properties on Noise, Vibration and Harshness Phenomena

2020-01-151009/30/2020

Noise, vibration and harshness (NVH) phenomena can manifest themselves during the engagement and disengagement of dry friction clutch systems. Such phenomena can have a negative impact on cabin occupants’ driving experience as well as on others in the immediate vicinity of the vehicle. Typically, unwanted NVH phenomena that pertain to the clutch system include Judder, Chatter, Squeal and Eek. These are recognized by the quality of the radiated noise, as well as the dynamics occurring during clutch actuation. The aim of the current study is to utilize a numerical clutch system model (fully coupling the main motions of the clutch components) to predict clutch dynamics during engagement manoeuvres. The model will be used to assess the effect of various clutch design parameters on mitigating system instability. The clutch model utilizes measured coefficient of friction data from a rotary tribometer at representative slip speeds and friction surface contact pressures. The paper highlights

Minas, Ilias, Morris, Nicholas, Theodossiades, Stephanos, O'Mahony, Martin, Voveris, Jeronimas

Engine Flywheel Housing and Mating Transmission Housing Flanges

J617_202009-TEST-REC (Historical)09/29/2020

This SAE Standard specifies the major dimensions and tolerances for Engine Flywheel Housings and the Mating Transmission Housing Flanges. It also locates the crankshaft flange face or the transmission pilot bore (or pilot bearing bore) stop face in relation to housing SAE flange face. This document is not intended to cover the design of the flywheel housing face mating with the engine crankcase rear face or the design of housing walls and ribs. Housing strength analysis and the selection of housing materials are also excluded. This document applies to any internal combustion engine which can utilize SAE No. 6 through SAE No. 00 size flywheel housing for mounting a transmission.

Automatic Transmission and Transaxle Committee

Engine Flywheel Housing and Mating Transmission Housing Flanges

J617_202009 (Current)

09/29/2020

Automatic Transmission and Transaxle Committee

Thermal Analysis of Clutch Assembly Using Co-Simulation Approach

2020-28-002408/18/2020

Automotive clutches are rotary components which transmits the torque from the engine to the transmission. During the engagement, due to the difference in speed of the shafts the friction lining initially slips until it makes a complete engagement. Enormous amount of heat is generated due to the slippage of the friction lining, leading to poor shift quality and clutch failure. Depending on the road & traffic conditions, and frequency of engagement and disengagement of the clutch, it generates transient heating and cooling cycles. Hill fade test with maximum GVW conditions being the worst case scenario for the clutch. A test was conducted to understand the performance of the clutch, in which clutch burning was observed. The clutch lining got blackened and burning smell was perceived. The friction coefficient drops sharply to a point until it cannot transmit the torque required to encounter the slope. This further worsen clutch slippage and lead to more severe temperature rise. The major

Santra, Tanmay Sushant, Gopinathan, Nagarajan, Raju, Kumar, Sugumar, Ganesh, Paradarami, Udaya, Vellandi, Vikraman

A Comprehensive Study on the Challenges of Dual Mass Flywheel in Real-World Operating Conditions of the Indian Market

2020-01-101404/14/2020

The present work is focussed on the real-world challenges of a dual mass flywheel (DMF) equipped vehicle in the Indian market. DMFs are widely used to isolate the drivetrain from the high torsional vibrations induced by the engine. While DMFs can significantly improve noise, vibration and harshness (NVH) characteristics of a vehicle, there are multiple challenges experienced in real-world operating conditions when compared with the single mass flywheel (SMF). The present work explains the challenges of using a DMF in a high power-density diesel powertrain for a multi-purpose vehicle (MPV) application in the Indian market. Measurements on the flat-road operating conditions revealed that the DMF vehicle is very sensitive for launch behaviour and requires a higher clutch modulation. Vibration measurements at the driver’s seat confirm that the SMF vehicle could be launched more comfortably at the engine idle speed of 850 RPM. However, the DMF vehicle needs a "launch assist" of an

Vellandi, Vikraman, Somarajan, Suresh Kumar, Ganesh, Mohan Selvakumar

Development of a Component Level Test Methodology to Validate the Transmission Bush of a Manual Gear Box

2020-01-140904/14/2020

In the era of fierce competition, launching a defect free product on time would be the key to success. In a modern automobile, the transmission system is designed with utmost care in order to transfer the maximum power from engine to driveline smoothly and efficiently. Optimized design of all the transmission components is necessary in order to meet the power requirement with the least possible weight. This optimization may require gear designs with different internal diameters. The assembly of these gears may not be possible on a solid transmission shaft. To facilitate assembling while retaining optimum design of transmission parts, a separate bush is designed to overcome this limitation. Some bushes may require a flange to restrict any free play of the mounted gear in its axial direction. During complete system level testing of one newly developed manual transmission, bush failure was observed. Bushes are generally press fitted on the transmission shafts, on which the needle roller

Kathrecha, Devanshu, Chakraborty, Abhirup, Sirur, Avinash, Sebastian, Jobin, Savla, Jinesh

Characterization and Modeling of Wet Clutch Actuator for High-Fidelity Propulsion System Simulations

2020-01-141404/14/2020

Innovations in mobility are built upon a management of complex interactions between sub-systems and components. A need for CAE tools that are capable of system simulations is well recognized, as evidenced by a growing number of commercial packages. However impressive they are, the predictability of such simulations still rests on the representation of the base components. Among them, a wet clutch actuator continues to play a critical role in the next generation propulsion systems. It converts hydraulic pressure to mechanical force to control torque transmitted through a clutch pack. The actuator is typically modeled as a hydraulic piston opposed by a mechanical spring. Because the piston slides over a seal, some models have a framework to account for seal friction. However, there are few contributions to the literature that describe the effects of seals on clutch actuator behaviors. In a routine simulation, a spring constant is commonly tuned to match vehicle data, assuming that it

Haria, Hiral, McCallum, James, Fujii, Yuji, Tsuchiya, Takahiro, Miyagawa, Masatoshi, Nakamura, Shinji, Wendel, Matthew, Katopodes, Nikolaos

Active and Passive Control of Torsional Vibration in Vehicle Hybrid Powertrain System

2020-01-040804/14/2020

The vibration characteristics of hybrid vehicles are very different from that of traditional fuel vehicles. In this paper, the active and passive control schemes are used to inhibit the vibration issues in vehicle hybrid powertrain system. Firstly the torsional vibration mechanical model including engine, motor and planetary gear subsystems is established. Then the transient vibration responses of typical working condition are analyzed through power control strategy. Consequently the active and passive control of torsional vibration in hybrid powertrain system is proposed. The active control of the motor and generator torque is designed and the vehicle longitudinal vibration is reduced. The vibration of the planetary gear system is ameliorated with passive control method by adding torsional vibration absorbers to power units. The vibration characteristics in vehicle hybrid powertrain system are effectively improved through the active and passive control.

Zhang, Lijun, Zhang, Shijuan, Meng, Dejian, Xu, Jie

A Study on the Development of the CPA (Centrifugal Pendulum Absorber) Reducing the Rattle & Booming Noise in the Manual Transmission Vehicle

2020-01-039704/14/2020

In recent years, the automotive engine strategies are forced on downsizing and down speeding to enhance fuel economy and reduce the emission. These make torque increase significantly in order to improve the vehicle performance, especially in diesel engines. At this time, the torsional damper performs the most important role in the driveline NVH of the manual transmission system. The clutch disk with torsional dampers is not easy to be applicable to the high torque of low speed RPM range. And* DMF with sufficient isolation of vibrations of driving system includes disadvantages of the expensive cost, delayed response, and engine NVH aspect deteriorated due to increase of angular acceleration of engine. This paper presents that the Centrifugal Pendulum Absorber (CPA) is applied to maximize the isolation and to compensate for the disadvantages of DMF and SMF system. Furthermore, CPA was developed for the first time in the world on SMF clutch discs in manual transmission.

Kim, Ukjin

Development of GM Allison 10-Speed Heavy Duty Transmission

2020-01-043804/14/2020

This paper describes the development of the GM Allison 10-Speed Heavy Duty (HD) Transmission. The trend of increased towing capacity and engine horsepower in the automotive heavy-duty truck segment has been steadily climbing for the past 10 years. The development of 10-Speed HD Transmission is designed to be best in class in for towing performance in the 2500/3500 series segment while optimizing fuel economy. The 10-Speed HD Transmission also gives the customers the option to order an integrated power take-off (PTO) unit that benefits downstream installation of utility accessories such as hydraulic pumps, generators, etc.

Lee, Chi Teck, Ames, David, Caldwell, Brett, Knoth, Matthew, Reinhart, Timothy, Kelly, Jeffrey, Kannan, Rajesh, Tanasi, German

An Iterative Method to Determine Clutch Clearances in Torque Converters by Integrating the Fluid and Structure Analyses

2020-01-093604/14/2020

Determining an amount of clutch clearance for the lockup device in a torque converter is important for its being operating precisely in the intended mode. Challenges may exist for the torque converters whose nominal clearances are on purpose very small. Any potential changes in the clutch lockup system (e.g., due to the deformation of components) may make such a small clearance instantaneously diminish during the mode of open-clutch, thus leading to unwanted drag in the clutch and unnecessary loss of energy. In the open-clutch mode, the actual clutch clearance may be different from the nominal clearance anticipated, primarily because of deformation caused by the internal load acting on clutch members. It has been found that the pressure distribution in a clutch chamber also depends on the very clutch gap through which the fluid flows. This interdependence between the fluid pressure load and structural deformation is typical of two-way coupling in simulation. As an alternative approach

Yang, Zane, Jeyabalan, Subramanian, Khajamohideen, Abdur-Rasik, Solaimalai, Maheshkannan, Rajendhran, Dhashnakumar

A Study of Mechanism of Engine Idling Rattle Noise in Hybrid Transaxles

2020-01-042104/14/2020

Quietness is one of the most important characteristics for Hybrid Electric Vehicle quality. Reduction of the rattle noise caused by the torque fluctuation of an internal combustion engine can contribute to get a customer satisfaction. Toyota Hybrid System(THS) also has same requirement. Especially, the rattle noise during idling may happen discontinuously despite of periodical engine combustion excitation. It is necessary to study the mechanism and reduce the rattle noise. At lower engine torque range, decreasing the torsional damper’s stiffness can improve this condition as the manual transaxle done. However, the rattle noise can occur easily in conditions of relatively large torque spike inputs to the torsional system, such as the engine start/stop function of THS using the motor/generator in the transaxle. It is necessary to analyze the dynamics of all related components in lower engine torque range and need to find the new technique satisfying in both the idling and engine start

Takeuchi, Tomoya, Miyasaka, Kenji, Ito, Masatoshi, Nakamura, Shingo

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

2019-32-052301/24/2020

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

Minoha, Misaki, Yoneyama, Koji, Imai, Ryoichi, Kitazawa, Hidenori, Mano, Osamu, Miyagawa, Shinya

Optimized Wet Clutch Design

2019-32-055301/24/2020

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

Bhone, Nitin, Thakare, Sachin, Jahagirdar, Ashutosh

Advanced Bench Test Methodology for Generating Wet Clutch Torque Transfer Functions for Enhanced Drivability Simulations

2019-01-234012/19/2019

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

Haria, Hiral, Fujii, Yuji, Pietron, Gregory M., Sun, Anna, Tsuchiya, Takahiro, Miyagawa, Masatoshi, Nakamura, Shinji, Wendel, Matthew, Miyoshi, Hiroya, Wang, Pengchuan, Katopodes, Nikolaos

Torque and Pressure CFD Correlation of a Torque Converter

06-12-03-001208/22/2019

A torque converter was instrumented with 29 pressure transducers inside five cavities under study (impeller, turbine, stator, clutch cavity between the pressure plate and the turbine shell). A computer model was created to establish correlation with measured torque and pressure. Torque errors between test and simulation were within 5% and K-Factor and torque ratio errors within 2%. Turbulence intensity on the computer model was used to simulate test conditions representing transmission low and high line pressure settings. When turbulence intensity was set to 5%, pressure simulation root mean square errors were within 11%-15% for the high line pressure setting and up to 34% for low line pressure setting. When turbulence intensity was increased to 50% for the low line pressure settings, a 6% reduced root mean square error in the pressure simulations was seen. For all pressure settings, cavities closer to the converter inlet required a 5% turbulence intensity while the cavities inside or

De Jesus Rivera, Edward, Woodland, Mark, Robinette, Darrell, Blough, Jason, Anderson, Carl, Frait, Steve, Devendran, Ram

Dual Clutch Transmission Vibrations during Gear Shift: A Simulation-Based Approach for Clunking Noise Assessment

2019-01-155306/05/2019

A novel methodology, for the assessment of Dual Clutch Transmission vibrations during gear shifts, is proposed in this paper. It is based on the capability to predict through numerical simulation a typical dynamic quantity used to objectively evaluate the vibrational behavior of a gearbox during experimental tests, i.e. the acceleration of a point on the external surface of the gearbox housing. To achieve this result, a two-step approach is proposed: an accurate simulation of the internal transmission dynamics and an offline uncoupled computation of the gearbox housing acceleration from the output of the simulation. The first step required the definition of a suitable nonlinear lumped parameter model of the car equipped with a DCT that was implemented in Amesim software. The second step, developed as a post processing tool in Matlab, is based on the knowledge of the inertance Frequency Response Functions (FRFs) between a single component of force applied in a bearing and a single

Galvagno, Enrico, Dimauro, Luca, Mari, Gianluca, Velardocchia, Mauro, Vella, Angelo Domenico

A New Analytical Model for Clutch System Modeling and Design Optimization

2019-01-084004/02/2019

In manual transmission vehicles, Clutch has direct interaction with the driver and plays a significant role in defining the drivability and NVH of a vehicle. These key performance factors depend on the interaction of diaphragm and cushion springs of a clutch. For an automobile manufacturer, it’s essential to optimize the characteristics of these springs based vehicle performance requirements. A state of the art analytical model has been developed by modeling the diaphragm and cushion spring with exponential equations. Based on these models, response functions for release load, torque build-up, and pressure plate lift have been derived. Results achieved from these response functions are correlated with test data. Key contributing factors for peak clutch pedal load, vehicle launch acceleration, and disengagement point have been identified by sensitivity analysis. Multi-objective optimization is performed to select optimized parameters for vehicle performance improvement

Shandilya, Rahul, Rawla, Vikas

Analytical Estimation of Clutch Life for Manual Transmission

2019-01-033504/02/2019

The clutch is the connecting link between engine and the power train. It connects and disconnects the engine to the gearbox as per the wish of the driver. Clutch has a friction disc which acts like a fuse wire which wears in the process of the connection. This paper tries to calculate the clutch life analytically (In terms of Kms. run by vehicle), of automotive vehicles having manual transmission. As the clutch engages and disengages the engine to the gearbox, during this time due to slippage, energy is dissipated which results in the wear of the clutch disc. It calculates life based on the volumetric wear of the clutch disc and wear allowance available. The work done by other people in this domain include the empirical estimation of clutch life based on the past data, effect of the surface topography on the friction characteristics of the wet clutches, modeling of clutch housing and facing temperature for the estimation of the clutch life of a manual transmission etc. The present work

Mishra, Anurag, Chollangi, Damodar

Application of Empirical Asperity Contact Model to High Fidelity Wet Clutch System Simulations

2019-01-130104/02/2019

Wet clutches are complex hydrodynamic devices used in both conventional and electrified drivetrain systems. They couple or de-couple powertrain components for applications such as automatic shifting, engine disconnect and torque vectoring. Clutch engagement behaviors vary greatly, depending on design parameters and operating conditions. Because of their direct impact on vehicle drivability and fuel economy, a predictive CAE model is desired for enabling analytical design verification processes. During engagement, a wet clutch transmits torque through viscous shear and asperity contact. A conventional Coulomb’s model, which is routinely utilized in shift simulations, is inadequate to capture non-linear hydrodynamic effects for higher fidelity analysis. Extensive research has been conducted over the years to derive hydrodynamic torque transfer models based on 1D squeeze film or 3D CFD. They are typically coupled with an elastic asperity contact model for mechanical torque transfer

Haria, Hiral, Fujii, Yuji, Pietron, Gregory M., Wang, Pengchuan, Katopodes, Nikolaos, Miyagawa, Masatoshi, Tsuchiya, Takahiro, Nakamura, Shinji, Wendel, Matthew, Miyoshi, Hiroya

Coordinated Mode Transition Control for a Novel Compound Power-Split Hybrid Electric Vehicle

2019-01-130604/02/2019

Because of the direct connection between the compound power split hybrid transmission (CPSHT) and the engine in hybrid electric vehicle (HEV), engine ripple torque (ERT) can lead to obvious jerks when the mode transition from electric driving mode to hybrid driving mode occurs. In order to enhance the riding comfort, two additional wet clutches are mounted in this novel CPSHT and the relevant coordinated control strategy is developed. Firstly, after the description of the mechanical and hydraulic parts of the novel CPSHT, the dynamic plant model including driveline model, engine ripple torque and clutch torque is deduced. Secondly, the mode transition process in the original and current designs are compared and analyzed with the equivalent level diagram and the encountered problems are stated. Thirdly, a coordinated control strategy is designed to determine the target motor torque, clutch torque, engine torque, and the moment of fuel injection based on the second-order sliding mode

Shen, Dengfeng, Guehmann, Clemens, Zhang, Tong

Modeling and Analysis of Clutch Engagement Judder in Commercial Vehicle Powertrain Systems

2019-01-078404/02/2019

Transient events in a vehicle driveline such as tip in tip out, clutch engagement-disengagement, engine start, etc. are very important considering NVH characteristics and hence comfort of a vehicle system overall. Clutch engagement (especially during vehicle launch from a rest condition) is one of the most important transient events in commercial vehicles utilizing automated manual transmissions (AMTs). This paper presents common NVH issues observed during vehicle launch in a commercial heavy duty truck. One of the most important NVH issues is clutch engagement judder. Judder is seen when torque fluctuations are generated in a slipping clutch which induce undesired driveline vibrations. This paper concentrates on friction judder as well as geometric judder. Different friction materials are compared for their performance against friction judder. Performance of friction materials with respect to slip speed, temperature, and pressure is also studied. Geometric judder and how cushion discs

Paygude, Tejas, Joshi, Rohit Ravindra

Selection of Rational Parameters of Automated System of Robotic Transmission Clutch Control on the Basis of Simulation Modelling

2019-01-002901/15/2019

The article deals with the analysis of one of the methods of selecting rational parameters of automated clutch control system for robotic transmission. The objective is to select rational parameters of automated clutch control system for robotic transmission, equipped with electropneumatic actuating mechanism on the basis of mathematical simulation. The depicted mathematical simulation of the clutch control system is characterized by the possibility to coordinate the algorithm of control unit with the dynamic processes in the execution device. The new functional interrelations between the elements of the electro-pneumatic actuator are mathematically described. The way to the selection of rational parameters of an automated control system for clutch is recommended; the selection taking into account the features of the electro-pneumatic actuator. Using the mathematical modeling method, rational control parameters of the automated clutch control system are determined. Based on comparative

Mikhalevich, Mykola, Yarita, Alexandr, Leontiev, Dmitry, Gritsuk, Igor V., Bogomolov, Viktor, Klimenko, Valeriy, Saravas, Viktoriya

Energy Based Analytical Study of Effect of Engine Calibration, Clutch Modulation on the Life of Dry Clutch in View of City Traffic Using Road Load Data

2019-26-033101/09/2019

Single plate dry clutch is one of the most abuse components in the vehicle. With the growing population of traffic in cities, useful life of clutch is affected drastically which is evident from the rise in complaints on clutch from metropolitan cities. The governing design parameter, which affects the life of clutch, is the energy dissipated in clutch per unit area of friction lining of clutch disc. The life of clutch is affected by many factors like vehicle weight, engine torque, driveline ratios, friction lining, size of clutch, which are taken into consideration during design stage of the clutch. Apart from these factors, one more factor, engine calibration, affects the clutch life drastically. However, it is not taken into consideration during design stage owing to its inherent nature as it gets matured over the vehicle development program. Engine calibration, especially driven idle speed calibration of engine in 1st, 2nd and 3rd gear for a particular vehicle, governs the vehicle

Mohire, Sujit, Katarki, Shrirang, Chaskar, Mithun, Uttamani, Rahul, Tendulkar, Vishveshvar

Study of Clutch Judder Phenomenon in Manual Transmission Vehicle and Its Analysis Approach

2019-26-021501/09/2019

Clutch engagement judder is a phenomenon wherein the driver experiences vibrations on seat during the clutch engagement process for the vehicle launch. Clutch engagement judder is one of the critical vehicle attributes as a part of overall vehicle NHV. Torsional oscillations, specifically originating from clutch in the driveline during clutch engagement, are referred as clutch engagement judder. Judder is a phenomenon wherein friction induced torsional vibrations are generated in the driveline because of sliding contact between clutch and flywheel, during engagement. These resulting oscillations inherit the first resonance frequency of the driveline. The engagement judder not only affects the dynamics of transmission system but also the vehicle, because of excitations being transferred to body via suspensions and mounts. Passengers experience these oscillations as vibrations during vehicle launch. If excitation level is high then it may cause discomfort to passengers. In addition to

Mohire, Sujit, Kapse, Ravi, Tendulkar, Vishveshvar

Performance Optimization of Commercial Vehicle Clutch Actuation System

2019-26-033401/09/2019

Rapid changes in competitive automotive market trends and customer expectations have forced automobile manufacturers to offer better products with more distinctive features and improved comfort, all at a lower cost. Occupant comfort within the cabin compartment and easy operation of peripheral controls are some of the important factors under consideration while choosing the vehicle over its competition. In the clutch actuation system, the clutch pedal is the first key customer touch point between driver and vehicle transmission hence its performance is most significant to the overall quality perception and customer appeal. The effect of high clutch pedal effort of the clutch actuation system is felt by the driver during heavy traffic conditions, where frequent gear shifts are required, this becomes an annoyance to the driver decreasing his productivity. In order to afford superior comfort and a smooth clutch feel to the driver during day to day driving, there is a need to optimize the

Phapale, Sandip

Necessity of Advance Damper Technology for Future Agriculture Domain

2019-26-019301/09/2019

There is an increasing demand from end-users of tractors for longer clutch durability, reduction in driver fatigue and comfort during field operations. Tractor manufacturers are moving towards Wet Clutch Pack with torsion dampers to meet this emerging customer needs. However, in Conventional Torsion Dampers, there is a technical challenge to withstand harsh clutch engagement or high unexpected impacts of agri-implements, which are common in field operations. This is in addition to, torsional vibrations produced by the power-train. There are constraints, to further optimize a conventional damper without compromising important parameters like factor of safety, noise and durability issues. Hence the proposed next generation damper technology can meet all the new technical requirements and can ensure smooth and durable power shift transmission in tractors. This case study has been done with help of SCHAEFFLER’s tailor made “Tornado Instrument” and “Software” by acquiring real time data

Bagadekar, Vijaykumar Shankar, Alavilli, Satya Pavan, Kadhar Maideen, Salim Malik, Rajendran, Ashok Kumar, Radhakrishnan, Padmanaban, Soni, Sandeep

Method Development to Virtually Validate Farm Tractor Skid for Front End Loader Application

2019-26-008001/09/2019

In farm tractors, front end loaders are becoming popular attachments for primarily material handling such as loading, moving and unloading of woodchips, sand, gravels etc. It is also used for some severe load application such as tree uprooting and ripping operation which requires validation of loader frame and tractor as well. To validate the design, a standard pull-push test is carried out on tractor with loader in a laboratory. In this test front loader bucket is pushed against a rigidly clamped fixture with full engine throttle and maximum hydraulic cylinder pressure of loader. To avoid surprise failures during the test, a virtual simulation method needs to be developed and validated. In this paper, a method has been proposed by authors for the above objective. A multi-body dynamics model of tractor with loader is created in MSC ADAMS and actual event is simulated using test loads & boundary conditions. Forces and moments are extracted on all tractor skid attachments points from MBD

Subbaiyan, Prasanna Balaji, Kumar, Abhay, Mayur, Jaju, Nizampatnam, Balaramakrishna, Bhanuprakash, S.A, Schneider, Dave

Optimization of the Lubrication Distribution in Multi Plate Wet-Clutches for HVT Transmissions: An Experimental - Numerical Approach

2018-01-182209/10/2018

The paper investigates the lubrication flow within multi plate wet-clutches for hydro-mechanical variable transmissions in order to optimize the oil distribution and to reduce the thermo-mechanical stresses on the plates. Since experimental measurements are very difficult to carry out on a real system, CFD numerical tools are used for predicting the flow distribution in a real geometry under actual operating conditions. A modular approach is adopted for the domain subdivision in order to represent accurately the three dimensional geometrical features, while the volume of fluid approach is used to model the multi-phase flow that characterizes the component. Poor lubrication is predicted where high thermal stresses were observed during tests. Furthermore, the numerical modeling is validated against measurements carried out on an ad-hoc designed test rig, which adopts transparent PMMA and 3D-printed inserts for the flow investigation. Fast imaging techniques are used to capture the

Terzi, Stefano, Manhartsgruber, Bernhard, Milani, Massimo, Montorsi, Luca

Influence of Clutch Tribodynamics on Drivetrain Noise, Vibration and Harshness, (NVH), Phenomena

2018-01-153706/13/2018

Limiting problematic Noise, Vibration and Harshness (NVH) phenomena in the modern automotive drivetrain is a task of critical importance. The result of such phenomena is the aggravation of the driver, which results in a reduced perception of vehicle quality. Each phenomenon can be characterized by a distinct frequency range. The aim of the current study is to assess the influence of the interfacial frictional behavior of the dry friction clutch components on the drivetrain dynamic behavior. The dynamics of the system (in terms of its stability) are studied. Surface data from the clutch components are critical to understanding the complex engagement process. The coefficient of friction was measured using a rotary tribometer at representative slip speeds and contact pressures. To aid the analysis infinite focus microscopy was used to measure the geometric properties of the constituent components of the drivetrain. The current approach allows for improved understanding of the drivetrain’s

Minas, Ilias, Morris, Nicholas, Theodossiades, Stephanos, O'Mahony, Martin

Interior Noise Refinement in an ICV Bus through Driveline Torsional Vibration Analysis

2018-01-147206/13/2018

With a push for urbanization across cities, there is an increased demand for mobility in public transportation especially buses which are provided through state transport undertakings. Hence, the expectations of this class of vehicles will be high in terms of quality and comfort to the passengers. The noise inside the passenger area of the bus becomes an important parameter, which sets apart a bus manufacturer from its competitors. The driveline of the bus is the system responsible for the transfer of power from engine to the wheels. The noise and vibration problems associated with it are detected only in the late stages of the design chain, when all its elements are tested together over a wide range of conditions. Since, calibration of engine and the selection of transmission is freezed in early stages, satisfying power and torque requirements, the only viable option left to address the problem is by optimizing the clutch parameters. Combustion in multi-cylinder four stroke diesel

Kamani, Keval, Kannan, P, P, Sivaraman

Virtual Simulation for Clutch Thermal Behavior Prediction

2018-37-002105/30/2018

The clutch is that mechanical part located in an internal combustion engine vehicle which allows the torque transmission from the shaft to the wheels, permitting at the same time gear shifting and supporting engine revolutions while the car is idling. This component exploits friction as working principle, therefore heat generation is in its own nature. The comprehension of all the critical issues related to thermal emission, and also of the principal physical parameters driving the phenomena are a must in design phases. The subject of this paper is the elaboration of an accurate, but also easy to use and easily replicable, methodology to simulate thermal behavior of a clutch operating inside its usual environment. The present methodology allows to prevent corrective actions in the last phase of the projects (real testing), such as changes in gear ratios, that likely worsen CO2 emissions, permitting to achieve the wished thermal performance of the clutch avoiding late changes. Using

Tosi, Fabio, Gautero, Matteo, Lorefice, Laura, Paola lng, Nicola

Conceptual Design Challenges and Solutions in Power Shuttle Transmission Development for Legacy Tractors

2018-01-039404/03/2018

Current developments in tractor transmission design has galloped to new heights with the introduction of CVT, Power shift, Power shuttle, hydrostatic etc besides the vastly available synchromesh and constant-mesh gearboxes. In contrary to the above existing facts of new powertrain development, there is a definite market need to revamp the heritage tractor models to be equipped with the modern transmission systems. This will help customers to have the advanced drivetrain features in the legacy tractors that have won many hearts. One such modernization was the development of new power shuttle transmission in legacy tractor models for TAFE tractors. Power shuttle primarily enables a tractor - in this case, to go forward and reverse by operating a wet clutch. A flick of lever, usually on the steering column changes the direction of the tractor at the same speed of the gear selected. This research work is on the various conceptual drivetrain challenges akin to ground speeds, base drivetrain

Rajagopal, MahendraMohan

Derivation of Test Schedule for Clutch Using Road Load Data Analysis and Energy Dissipation as Basis

2018-01-038904/03/2018

During every clutch engagement energy is dissipated in clutch assembly because of relative slippage of clutch disc w.r.t. flywheel and pressure plate. Energy dissipated in clutch is governed by many design parameters like driveline configuration of the vehicle vis-a-vis vehicle mass, and operational parameters like road conditions, traffic conditions. Clutch burning failure, which is the major failure mode of clutch assembly, is governed by energy dissipation phenomenon during clutch engagement. Clutch undergoes different duty cycles during usage in city traffic, highways or hilly regions during its lifetime. A test schedule was derived using energy dissipated during every clutch engagement event as a base and using road load data collected on the vehicle. Road load data was collected in different road mix conditions comprised of city traffic, highway, hilly region, rough road for few hundred kilometers. Using this data clutch energy was calculated in all the clutch engagement events

Mohire, Sujit, Chatterjee, Soumik, Bhandari, Kiran Kamlakar

Simulation to Estimate the Output Torque Characteristics and Temperature Rise of a Transmission Wet Clutch during the Engagement Process

2018-01-040204/03/2018

During a typical shift event, one or more clutches are brought to engagement while others are released in order to change the torque transmission path. A mismatch in torque level and handshake timing between the off-going and on-coming clutches affects the shift quality. In order to capture the dynamic behavior of the torque response and estimate the temperature rise at the friction disk and separator plate interfaces during the engagement process, several numerical models have been developed. The earliest of these models was presented by Berger et al. which was later modified and enhanced by Natsumeda et al. and Yang et al. However, these models cannot capture the dynamic behavior of grooved clutch disks. Hence, development of a wet clutch engagement simulation model using commercial CFD simulation tool, which can capture the dynamic behaviors of no groove and grooved disks, becomes a pressing need. In this paper, we have presented an engagement simulation model using Star CCM

Mahmud, Syeda Faria, Pahlovy, Shahjada A., Ogawa, Makoto

Derivation of Test Schedule for Clutch Using Road Load Data Analysis and Energy Dissipation as Basis

2018-01-040404/03/2018

Mohire, Sujit, Uttamani, Rahul, Tendulkar, Vishveshvar, Katarki, Shrirang, Patil, Shahaji

Development of an Analysis Program to Predict Efficiency of Automotive Power Transmission and Its Applications

2018-01-039804/03/2018

Prediction of power efficiency of gear boxes has become an increasingly important research topic since fuel economy requirements for passenger vehicles are more stringent, due to not only fuel cost but also environmental regulations. Under this circumstance, the automotive industry is dedicatedly focusing on developing a highly efficient gear box. Thus, the analysis of power efficiency of gear box should be performed to have a transmission that is highly efficient as much as possible at the beginning of design stage. In this study, a program is developed to analyze the efficiency of an entire gearbox, considering all components’ losses such as gear mesh, wet clutches, bearings, oil pump and so on. The analytical models are based on the formulations of each component power loss model which has been developed and published in many existing papers. The program includes power flow analysis of both a parallel gear-train and a planetary gear-train. The program is also implemented with the

Park, Kijong, Kang, Maru, Lee, Jihun, Son, Woo Churl, Harianto, Jonny, Kahraman, Ahmet

General Motors Hydra-Matic 9T50 Automatic Transaxle

2018-01-039104/03/2018

General Motors Global Propulsion Systems’ first nine-speed automatic transmission makes its debut in the 2017 Chevrolet Malibu, advancing a legacy of multispeed transmissions designed to optimize efficiency, performance and refinement. The Hydra-Matic 9T50 nine-speed is paired with a Ecotech 2.0L Turbo engine in the Malibu, contributing to an EPA estimated 33 mpg highway, a three-percent increase over the 2016 Malibu with an eight-speed automatic paired to the same engine. The 9T50 has a wider 7.6:1 overall ratio, which is the ratio between the first gear ratio and the top gear ratio, - compared to the six-speed’s 6.0:1 ratio. The 9T50 is fitted with a “deep” 4.69 first gear ratio for excellent off-the-line acceleration and a “tall” 0.62 top gear ratio for low-rpm highway cruising. That balance optimizes acceleration and fuel economy while reducing engine noise during cruising. With nine available forward ratios, the step size between the gears is reduced providing smooth, precise

Martin, Thomas, Hendrickson, James

Development of New Groove Design for Reduction of Drag Torque or Spin Loss of Disengaged Wet Clutches in the High Speed Region

2018-01-130004/03/2018

The typical graph of a drag torque or spin loss vs. speed of disengaged wet clutch of automotive transmission shows 4 types of trends. First one is increasing until a peak level, next decreasing to the lowest level, next saturating or being no change, and last again increasing. If the absolute value of drag torque at high speed (6000-20,000rpm) is high, the possibility of fluttering of friction disk, chipping, burning and delamination of friction materials will be high. Moreover, the efficiency of a transmission will be dropped and the life of it become shorter. Therefore, it is important to understand the physics behind the torque jump up at high speed. In our previous study, we investigated the possible reasons of torque jump up at high rotation speed. In this paper, we have extended our previous study and developed new groove design to reduce the drag toque in the high speed range. Result shows that a significant amount of drag torque in the high speed range can be reduced by a new

Pahlovy, Shahjada A., Mahmud, Syeda, Ogawa, Makoto

Dog Clutch Without Circular Backlash

2018-01-129904/03/2018

The paper is dedicated to design of a new dog-clutch gearshift mechanism for passenger car gearboxes with external synchronization. There are two main targets of presented work: 1 Replace the standard synchronizer with cheap and compact shift device, which will keep the internal architecture of classical manual transmission. 2 Keep all the other important functions of synchronizer: a minimal circular backlash to avoid clash during change of sense of the torque flow, b prevent unwanted disengagement, c guarantee the shift anytime, d determine neutral position (preferably). Czech Technical University in Prague is for several years active in the field of design and testing of shift mechanisms, as well as in design of new shift clutches. The currently presented clutch is 3rd generation of inventions of dog clutch systems. All clutches were fabricated as prototype and tested. All designs will be briefly described in the paper. To observe the real life function the prototype was assembled

Achtenova, Gabriela, Jasny, Michal, Pakosta, Jiri

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