Browse Topic: Clutches

Items (1,631)

Clutch Torque Optimization for Heavy-Duty Vehicles Starting Based on Intelligent Identification of Driver’s Starting Intention, Vehicle Mass, and Road Grade

02-17-03-001810/08/2024

For heavy-duty vehicles equipped with automated mechanical transmission (AMT), the control of automatic clutch torque is crucial during the start-up process. However, the difficulty of controlling clutch torque is exacerbated by differences in driver’s starting intentions, changes in vehicle mass, and road gradient. Therefore, this article proposes the clutch starting torque optimization strategy based on intelligent recognition of driver’s starting intention, vehicle mass, and road gradient. First, an intelligent recognition strategy is proposed based on the combination of data-driven and onboard transmission control unit (TCU) algorithms, which improves the accuracy of recognizing the driver’s intention to start as well as the vehicle mass and road gradient. Based on the vehicle’s historical state data information, the predictive model is trained offline using a long–short-term memory (LSTM) network to obtain predicted parameter identification results, which are then used to

Geng, Xiaohu, Liu, Weidong, Lei, Yulong, Fu, Yao, Xue, Maohan

Development of Transmission adaptor for diesel engine application

2024-26-033601/16/2024

Transmission adapter is solid, located on cylinder block , on which sits the transmission housing. The function of a flexplate is to provide a mounting point for a torque converter which is used to couple the engine and transmission together when an automatic transmission is used. Transmission adapter provide access for torque convertor and flexplate assembly and protect the flexplate from external environment. Transmission adapter is also support and locate the starter. This study deals with different alloy grade material use, improvement in process to reduce porosity. Porosity observed in first samples of the proposed grade material. The study represents investigation of Transmission adaptor porosity root cause. This also included visual observation, radiography -X ray testing , analysis,3D scan, dimensional inspection, chemical analysis and comparison, tensile testing, truck testing validation tasks. Make sure critical parameter of the clearance meet between flexplate and

Karale, Pranjali

A Study on Reduction of Gear Rattle Noise through Clutch Hysteresis Stabilization

2025-01-010005/05/2023

Reducing gear rattle noise within the passenger cabin is a crucial objective in vehicle development due to its direct impact on customer comfort and driving experience. Gear rattle occurs when free gears collide during meshing, primarily driven by high torsional vibrations generated by engine fluctuations. These vibrations are transmitted through the clutch system to the transmission, amplifying noise inside the cabin. To address this issue, this study focuses on optimizing the clutch by stabilizing its hysteresis, which helps in minimizing the torsional vibrations transferred to the transmission input shaft, thereby reducing gear rattle. The investigation centers on a case where significant gear rattle was observed at high vehicle speeds, particularly under high engine torque conditions. A thorough root cause analysis identified that the primary contributor to the noise was a drop in the clutch hysteresis value at elevated engine torques. This drop increased torsional vibrations in

Awasthi, Mradul, Dhankhar, Dinesh Singh, Khare, Devendra Kumar, Rana, Deepak, pandey, Anant

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

Reduction of Lubrication System Pressure Pulsation due to Oil Foaming in a Double Clutch Transmission

2022-28-048711/18/2022

Foaming of Oil is accumulation of air bubbles on the surface. The source of air can be environmental or dissolved air or both. Foaming of Lubricant Oil is an undesired effect which has various reasons to occur- sudden decrease of pressure, contamination, reservoir design, etc. The effects can be pressure pulsation in pump discharge which results in abnormal Noise and Vibration, Cavitation, etc. This paper will describe the mechanical design changes done in a gearbox to guide the Oil flow to a less turbulent passage and to the reservoir. This will allow oil to degas while its flow to the reservoir, largely losing its foamability characteristic. By introducing circular enclosing structure around the rotating Clutch pack, the centrifugally escaping oil is guided and escapes into a collection tray via single point opening. The Oil tray will route the oil back to the reservoir. The enclosing structure around the Clutch pack is a carefully designed two-parts structure with close and

Balasubramani, Prathap, Kaushik, Nikhil

Normally Locked Torque Converter as an Alternative Mutli-speed Transmission for Electric Vehicles

2022-01-077503/29/2022

An emerging trend in electric vehicle (EV) propulsion system engineering is the proposal of a wide range of two-speed transmission to improve performance, energy consumption and potentially alter electric motor characteristics. This paper proposes the design and integration of a torque converter and clutch-damper assembly that is normally locked as an alternative means of achieving a two-speed transmission for EV drive units. The layout of the drive unit with the torque converter is included along with an overview of the hydraulic system and control strategy to minimize energy consumption. The performance attributes required to match the torque converter to an electric motor verse an internal combustion engine are reviewed in the context of achieve comparable performance to a two speed transmission tractive effort. Dynamometer testing of a torque converter in both rotational directions is provided to highlight the preferred method of operation during reverse operation of the drive unit

Robinette, Darrell

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

Vehicle surge reduction technology during towing in parallel HEV pickup trucks

2022-01-073303/29/2022

In order to ensure the comfort of the parallel HEV pickup truck, this report proposes a vehicle surge reduction technology during towing that utilizes a motor and shifting. Hybridization is one of the approaches to reduce fuel consumption toward the realization of carbon neutrality. The parallel HEV is more advantageous to high-load operation such as towing and loading, which are often used in pickup trucks than the series parallel HEV represented by the Toyota Hybrid System. Since the parallel HEV has an engine, motor, torque converter, and transmission connected in series, a vehicle surge may occur when engaging the lockup clutch due to fuel efficiency and drivability needs, as with conventional powertrains. Vehicle surge is a low-frequency vibration phenomenon. In general, the applied force is the torque fluctuation caused by the engine and tires, and the amplification is the driveline torsional first-order resonance, suspension resonance, and cabin resonance. The vibration is more

Okaya, Shingo, Kokaji, Jun, Quinteros, Luis, Hasegawa, Yoshio, Masunaga, Seiji

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

Optimization of Gaussian Process Regression Model for Characterization of In-Vehicle Wet Clutch Behaviors

2022-01-025303/29/2022

The advancement of Machine-learning (ML) methodology enables a data-driven creation of Reduced Order Model (ROM) for automotive components and systems. In recent years Gaussian Process Regression (GPR) has emerged as a powerful tool for building a static ROM as an alternative to a conventional parametric method. It provides a mathematical framework for probabilistically representing complex non-linear behaviors. Today GPR is available in various programing tools and commercial CAE packages. However, its application requires a careful design consideration such as a selection of input features and a specification of kernel functions, depending on the characteristics of a target system. The GPR design optimization is also driven by application requirements. For example, a moving window size must be tuned to balance performance and computational efficiency for tracking changing system behaviors. In this paper, a detailed design evaluation of GPR is conducted for the characterization of an

Shui, Huanyi, Zhang, Yijing, Yi, Elbert, Bichkar, Akshay, McCallum, James, Upadhyay, Devesh, Miller, Justin, Hopka, Michael, Fujii, Yuji

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

Uncertainty Quantification of Wet Clutch Actuator Behaviors in P2 Hybrid Engine Restart Process

2022-01-079103/29/2022

Advanced features in automotive systems often necessitate the management of complex interactions between system components. To accomplish this task, closed-loop feedback is commonly used for effective real-time controls. Alternatively, open-loop schemes with adaptive parameters can be applied when real-time feedback is infeasible. Although these strategies possess certain levels of robustness, their performance can deteriorate in the presence of significant uncertainties, resulting in undesirable system behaviors. This limitation is often further amplified in systems with complex nonlinear dynamics. A hydro-mechanical clutch actuator is among those systems whose behaviors are highly sensitive to variations in sub-component characteristics and operating environment. In a P2 hybrid system, a wet clutch is utilized for cranking the engine during EV-HEV mode switching. It is critical that a controller is capable of stroking hydro-mechanical clutch actuator as quickly and as consistently as

Yang, Hang, Fujii, Yuji, Zhang, Yijing, Haria, Hiral, Devendran, Ram Sudarsan, Saini, Ankit, Gorodetsky, Alex, Wang, Kon-Well

Investigation of the Drag Losses of Wet Clutches at Dip Lubrication

2022-01-078803/29/2022

Wet running multi-plate clutches and brakes are important components of modern automotive and industrial powertrains. In the open stage, drag losses occur due to fluid shearing. This subsequently can lead to a perceptible reduction in the overall drivetrain efficiency. Depending on the application and requirements, injection or dip lubrication is used. For the first one there is already a deep fundamental understanding existing, whereas the latter was not extensively investigated so far. This contribution gives a detailed insight in the experimental research of the drag losses of wet running multi-plate clutches at dip lubrication. In a base study the flow conditions and origins of the drag torque generation were investigated. Built on this, the effects of operating and geometry parameters such as oil viscosity and level, clearance, groove design, disk size and number of gaps on the drag loss characteristic were determined based on a full-factorial testing. The paper further explains

Pointner-Gabriel, Lukas, Forleo, Cosimo, Voelkel, Katharina, Pflaum, Hermann, Stahl, Karsten

Innovative Experimental Approach towards Gear Rattle Investigation

2022-01-078403/29/2022

Today’s customers are very thoughtful towards a new vehicle purchase. Along with the vehicle performance, overall vehicle NVH quality is also one of the most important factor which affects their buying decision. During any new product development, gearbox rattle noise is a fundamental NVH problem which requires to be addressed and solved in the early stages. Gear rattle is an annoying noise phenomenon of the automotive transmission, which is mainly induced by torsional fluctuation of engine. This fluctuation is passed from clutch system to the transmission. The torsional vibration causes the free gears inside the transmission to impact each other, which generates so-called the gear rattle noise. The noise source of the gear rattle in the manual transmission is due to the impact of gears oscillating through their gear backlash and the noise will transfer into the vehicle cabin through the transmission case via shafts, bearings and vehicle structures. This paper describes an experimental

Vaishya, Abhishek Lakhanlal

Wheel Torque-based Control: Transmission Input Torque Determination and Inertia Compensation

2022-01-089703/29/2022

Traditionally, production vehicles have interpreted the driver pedal request as a transmission input torque demand. However, with the advent of electrified vehicles, where actuators are located at different positions in the drivetrain, and of autonomous vehicles, which are self-driving, there is a requirement to interpret the demand (either human or virtual) in the vehicle acceleration domain. To address this requirement, we develop a Wheel Torque-based longitudinal Control (WTC) framework, wherein the desired vehicle acceleration is first expressed as a wheel torque demand and then transformed into each actuator’s torque domain. For powertrains with a step-ratio transmission and a torque converter (TC), a key challenge of the WTC framework is the determination of the torque request in the transmission input domain, especially during open or slipping TC operation. This determination needs to take into account the Inertia Compensation Torque (ICT), i.e., the torque required to spin up

Roy, Judhajit, Ravichandran, Maruthi, Meyer, Jason, Zhao, Yanan

Toyota’s New Hybrid Unit “L4A0”

2022-01-079503/29/2022

Toyota developed a new hybrid unit “L4A0” for the new Tundra, which creates both good drivability and environmental performance. To ensure off-road, towing performance and typically truck driving characteristics, the unit is based on a transmission with a torque converter and multi-plate lock up clutch, and installing a motor and K0 clutch between the engine and transmission. The motor and K0 clutch are built into a module, making it possible to create new hybrid units by combining the module with various transmissions. The unit features many different motor controls. For example, in the case of step-in acceleration input, typically to achieve the desired output torque, a kick-down shift is necessary; however, utilizing “L4A0” both high response and high power output is realized without a kick-down shift. This is accomplished by assisting the engine with the motor during engine torque delay at low engine revolutions. Simultaneously, this contributed to better fuel economy by allowing

Tan, Guodong, Ikemura, Masashi, Hasegawa, Yoshio, Ohki, Takao, Baba, Masayuki, Nakamura, Atsuro, Herring, Craig, Niinomi, Atsushi, Hamano, Makoto, Mizoguchi, Yasuhiro

Adaptive control strategy for complex starting conditions of vehicles with dry dual clutch transmission

2022-01-033003/29/2022

For vehicles equipped with the dry dual clutch transmission, due to the diversity of starting conditions, it is a nontrivial task for control strategy to meet the requirements of all kinds of complex starting conditions, which is easy to cause large starting shock and serious clutch wear. Therefore, it is proposed in this paper an adaptive control strategy for complex starting conditions by adjusting two clutches to participate in the starting process at the same time. Based on establishing the transmission system model and clutch model, the starting conditions are identified in terms of starting speed, road adhesion, and driver's intention, in which the driver's intention is identified by fuzzy reasoning model. Based on the identification of starting conditions and considering the safety principle, it is selected the appropriate starting gear and clutch combination mode, and adjusted the combination speed of the two clutches to carry out an adaptive control strategy. The Simulink

Guo, Jun, Wu, Jinglai, Zhang, Yunqing

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

Assessing the effect of torque converter losses on the start emission and Engine stability in TGDI AT Vehicle

2021-28-018510/01/2021

The emission norms around the world are continuously changing and getting stringent with every revision. India is on its way to make its emission norms at par with that prevailing in the developed nations. The cold-start condition is an important factor affecting vehicle emissions from gasoline direct injection (GDI) and port fuel injection (PFI) engines. In this paper, the effects of change in torque converter losses on emissions are experimentally investigated in a TGDI AT vehicle. The instant engagement of the torque converter puts a sudden torque on the engine and thus affects its stability. Thus, to overcome the stability issue, Engine torque has to be simultaneously increased for smooth engagement. As a result, the likelihood of the slightly leaner air-fuel mixture in the cylinder, which results in higher Nox formation, is much greater in an AT vehicle than that of a similar MT vehicle. Additionally, the temporary ineffectiveness of motor vehicle emission controls at startup

RAI, ABHISHEK, SARAN KUMAR REDDY, KETHIREDDY, SOMANI, KAPIL

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 Improve the Clutch Pedal Characteristics of a Compact Sports Utility vehicle

2021-28-024310/01/2021

Clutch characteristics play a vital role in ensuring a smooth and comfortable customer experience of any vehicle. The expectation is to have an optimized clutch pedal effort, reduced pedal travel, adequate modulation zone and a smooth and quick pedal returnability. However, achieving all these customer requirements is extremely challenging in some cases. In the present work, the authors discuss on improving the clutch pedal characteristics of a compact sports utility vehicle (SUV by adapting a unique approach of combining a dual torsion spring (DTS) and a return spring (RS). DTS is widely used in the clutch pedal to improve the pre-load at zero travel (1.5 kg to 2.0 kg) to improve the pedal returnability in the free-play zone. Moreover, it is also quite helpful to reduce the peak pedal effort by giving a positive assistance. However, the introduction of DTS would also bring down the pedal effort (pedal holding force) at the end of the travel affecting the pedal returnability at the

Vellandi, Vikraman, Kanagaraj, Pothiraj

Optimization of Clutch pedal Vibration with hydraulic damper & influence on its position in resolving the vibration without compromising Efficiency of the system

2021-28-024710/01/2021

The clutch pedal in manual transmission plays a significant role in defining the comfort of driver as the component is one of the customer's touchpoint in the vehicle. Whenever driver operates the clutch pedal, comfort & NVH refinement should be felt over the complete pedal travel. The expectations of customer on NVH refinements, such as pedal vibration felt on foot during actuation, becomes the part of perceived Quality and hence addressing the concern is very crucial. Due to advancements of technology & down-sizing of engines, NVH becomes the challenging area where the clutch pedal vibrations need to be eliminated to improve the comfort. In this paper we are explaining the problem statement & NVH solution to eliminate the clutch pedal vibration observed during clutch pedal actuation. Pedal vibrations were very severe at 10% clutch pedal pressed condition, and the same tends to diminish till 50% clutch pedal pressed condition. From initial position (0% clutch pedal pressed condition

S, Kesavprasad, 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

Analytical methodology For the Prediction Of The Wear Of Damper Springs In Dry Friction Clutches

2021-26-038409/22/2021

Coil springs are crucial components of the clutch damper. Quantifying the stresses accumulated on them during operation is crucial in the prediction of remaining usable spring life. This paper demonstrates the use of a mathematical model based approach in predicting the behavior of localized stresses on the spring used in clutch dampers. An equivalent cantilever beam model for spring coils solved using the theory of elastic stability is utilized to predict the spring response in operation, a contact model that translates the spring response into localized stresses due to wear and iterative wear model that accounts for surface morphology and change in geometry due to wear is illustrated in this paper for the prediction of wear.

Anna Jothikumar, Saravana Kumar, Datta, Sauradeep, McCutcheon, Steve, Venkataraman, Aarkesh

Bus NVH refinement: A Journey towards Comfortable Future

2021-26-027209/22/2021

The future of bus transit in new millennium is promising. This optimism is based on an anticipated long-term slowdown in growth of suburbs and revitalization of central cities. It reflects and escalates the public concern with traffic congestion, sprawl and pollution. This calls for double the use of public transport to address above issues. It calls for changing the mind-set of society towards public transports like buses, coaches etc. This could happen if bus design ensures right comfort, safety & TCO by ensuring refined bus transport. Hence, it is responsibility of OEMs to provide the new generation buses and coaches, which will ensure the public demands of comforts in terms of NVH refinement. This paper covers the innovative approach used to convert the existing bus NVH refinement to next level as a short-term solution and with the intention of articulating NVH strategies for new generation bus development. This work explains combined experimental and simulation approach deployed

Doshi, Sohin, Taware, Girish, Kalsule, Dhanaji, Bijwe, Vilas, Naidu, Sudhakara

Slip energy evaluation for a conventional friction clutch

2021-26-048009/22/2021

The importance of clutch in a vehicle’s performance is not new to the automotive, commercial or agricultural sectors. So is the importance of the clutch life when it comes to the durability of a vehicle. In process of making the machines more and more efficient, one can observe a steady reduction in the overall mass of the vehicle and the parts in it. While the parts were heavier, and the friction lining surfaces were more than adequate, the life of clutch has been the best. But with reduction of the overall masses, the energy has lesser amount of sink to dissipate and is being liberated in the form of heat, rising the overall temperatures. This leads to an early wear or even a burn in the clutch. In such scenario, it is necessary to estimate accurately the energy dissipation through a defined cycle to understand the clutch performance. Although different methods exist to evaluate energy, most cases include obtaining a high amount of sophisticated data. This paper discusses a simpler

Alavilli, Satya Pavan, KADHAR MAIDEEN, SALIM MALIK

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

Customized and market specific thermal robust clutch system solution

2021-01-123909/21/2021

The goal of reducing fuel consumption and CO2-Emission is leading to turbo-charged combustion engines that deliver high torque at low speeds (down speeding). To meet NVH requirements damper technologies such as DMF (Dual Mass Flywheel) are established, leading to reduced space for the clutch system. Specific measures need to be considered if switching over from SMF (Single Mass Flywheel) to DMF. It has an impact on thermal behavior of the clutch system for example due to reduced and different distribution of thermal masses and heat transfer to surroundings. Taking these trends into account, clutch systems within vehicle power-trains are facing challenges to meet requirements e.g. clutch life, cost targets and space limitation. Clutch development process must ensure to deliver a clutch system that meets requirements taking boundary conditions such as load cycles and driver behavior into account. Relevant load cycles are derived based on feedback & an analysis of driver behavior under

Kapse, Ravi Ramesh, Lakshminarayanan, Saravanan, Németh, Ákos, Thakare, Ankit, Bernhardt, Johannes

Torque Limiters 101: Benefits, Types, and Comparisons

TBMG-3783710/01/2020

Modern machines can be simple — a single element translating a rotary-to-linear motion. They can also be complex — a collection of interacting mechanisms operating in a multi-dimensional plane. The commonality of these mechanisms is the element of motion that is predictable with a known torque or force and velocity.

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

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

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

Coordination Control Strategy for Mode Switching of a Parallel Hybrid Electric System Based on Continuously Variable Transmission

08/11/2020

This study aims to solve the problem of impact in a parallel hybrid electric system based on the continuously variable transmission (CVT) during switching from pure electric mode to engine-driven, power-generating mode. Taking into account the torque response characteristics of the engine and motor and the dynamic characteristics of the wet clutch hydraulic control system, the mode switching process is divided into six stages, namely, pure electric mode, wet-clutch free travel, engine start-up, engine speed synchronization, clutch combination, and engine intervention drive. A coordination control strategy is developed based on the model predictive control algorithm to ensure smooth mode switching. The effectiveness of the control algorithm is verified using Matlab/Simulink and the AMESim co-simulation platform. Results show that with the mode switching coordination control strategy, the components of the system work harmoniously. The maximum impact is reduced by 52.0% at the speed

Zeng, Xiaohua, Li, Xiaojian, Dong, Bingbing

A Reverse Engineering Method for Powertrain Parameters Characterization Applied to a P2 Plug-In Hybrid Electric Vehicle with Automatic Transmission

2020-37-002106/23/2020

Over the next decade, CO2 legislation will be more demanding and the automotive industry has seen in vehicle electrification a possible solution. This has led to an increasing need for advanced powertrain systems and systematic model-based control approaches, along with additional complexity. This represents a serious challenge for all the OEMs. This paper describes a novel reverse engineering methodology developed to estimate relevant but unknown powertrain data required for fuel consumption-oriented hybrid electric vehicle modelling. The main estimated quantities include high-voltage battery internal resistance, electric motor and transmission efficiency maps, torque converter and lock-up clutch operating maps, internal combustion engine and electric motor mass moment of inertia, and finally front/rear brake torque distribution. This activity introduces a list of limited and dedicated experimental tests, carried out both on road and on a chassis dynamometer, aiming at powertrain

Galvagno, Enrico, Millo, Federico, DiPierro, Giuseppe, Velardocchia, Mauro, Perazzo, Alessandro, Mari, Gianluca

On Prediction of Automotive Clutch Torsional Vibrations

2020-01-150806/03/2020

Automotive clutches are prone to rigid body torsional vibrations during engagement, a phenomenon referred to as take-up judder. This is also accompanied by fore and aft vehicle motions. Aside from driver behaviour in sudden release of clutch pedal (resulting in loss of clamp load), and type and state of friction lining material, the interfacial slip speed and contact temperature can significantly affect the propensity of clutch to judder. The ability to accurately predict the judder phenomenon relies significantly on the determination of operational frictional characteristics of the clutch lining material. This is dependent upon contact pressure, temperature and interfacial slip speed. The current study investigates the ability to predict clutch judder vibration with the degree of complexity of the torsional dynamics model. For this purpose, the results from a four and nine degrees of freedom dynamics models are compared and discussed. Subsequently, the predictions are compared with

Gkinis PhD, Theofilos, Rahmani, Ramin, Rahnejat, Homer

WHAT WE'RE DRIVING

20AUTP06_0806/01/2020

Four regular-sized adults onboard, I'm estimating 575 lbs (261 kg). A steep but abrupt grade of maybe 1.5 miles. One-third of the way up, a passing lane is available and there's our chance to get past a dawdler. Pin the 2020 Honda CR-V Hybrid's accelerator and from somewhere centered ahead of the firewall comes a raucous grumble-blare not all that different from opening up a big outboard motor. The sheer volume and tortured tenor cause everyone in the cabin to look at one another: “What the hell?” The CR-V Hybrid's “two-motor” system (already used to good effect in the Accord) is comprised of an AC synchronous motor dedicated to propulsion and geared in tandem with the 2.0-L 4-cylinder, both clutched to the differential. Another AC motor-generator is geared directly with the differential and largely charges the small 1.4-kWh lithium-ion battery. The setup is meant to bias the propulsion job to the 181-hp propulsion motor, with the engine providing electricity to the traction motor and

An LQR Approach of Automatic Transmission Upshift Control Including Use of Off-Going Clutch within Inertia Phase

2020-01-097004/14/2020

This paper considers using linear quadratic regulation (LQR) for multi-input control of the Automatic Transmission (AT) upshift inertia phase. The considered control inputs include the transmission input/engine torque, oncoming clutch torque, and traditionally not used off-going clutch torque. Use of the off-going clutch has been motivated by discussed Control Trajectory Optimization (CTO) results demonstrating that employing the off-going clutch during the inertia phase along with the main, oncoming clutch can improve the upshift control performance in terms of the shift duration and/or comfort by trading off the transmission efficiency and control simplicity to some extent. The proposed LQR approach provides setting an optimal trade-off between the conflicting criteria related to driving comfort and clutches thermal energy loss. It ensures tracking a linear-like profile of oncoming clutch slip speed reference, which was found to be nearly optimal based on control trajectory

Cvok, Ivan, Deur, Josko, Ivanovic, Vladimir, Zhang, Yijing, Fujii, Yuji

Dynamics and Control of Gearshifts in Wet-Type Dual Clutch Transmission for BEVs

2020-01-076704/14/2020

The dual clutch transmission is one of the possible choices for electric vehicle drivelines. The basic principle and control mode of shifting of wet dual clutch transmission are introduced, and the dynamic process of shifting of wet double clutch transmission is studied. Combined with the dynamic model of the wet clutch engagement process, the difference between the dynamic characteristics of the dual clutch transmission modeling using the Coulomb friction model and the dual-clutch transmission model using the average flow model and the micro-convex contact theory is analyzed. The shift control strategy of the dual clutch transmission proposes a correction method to improve the shifting smoothness. Studies have shown that the torque response of the wet clutch has significant hysteresis, and the improved control algorithm can significantly improve the shifting smoothness of the wet dual clutch transmission. Based on the dynamic model of the wet clutch, the torque interruption of the

Lou, Zhenxiong, Duan, Yupeng, Zhang, Yunqing

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

Testing of a wet plate clutch system for anti-shudder performance

2020-01-056004/14/2020

The wet clutch system ( WCS ) is a complex combination of friction plates, separator plates and lubricant. The basic function of the WCS is to transfer torque under various operating conditions such as slipping, shifting, start/launch and/or torque converter clutch operation. During these conditions the slope of the coefficient of friction versus slip speed ( µ-V ) curve must be positive to prevent shudder of the WCS. A test procedure is needed to evaluate the WCS over a durability duty cycle to monitor the µ-V curve slope and shudder potential. The clutch plates and fluid must be tested together and remain together during the test to evaluate as a WCS. The objective of this paper is to describe this new test procedure which builds on the basics of the SAE J2964 - Low Speed Continuous Slip µ-PVT test procedure but a duty cycle is added to age the WCS. The test includes measurement of the µ-V slope at several intervals during the test ( before break in, after break in, and after each 12

Diemer, Larry, Bares, Jason, Greening, Brent, Ezanno, Philippe, Whitticar, David, Klotchikhine, Vladimir, Greening, Charles

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

Launch and Lock with Multi-input Multi-Output Converter Control

2020-01-026204/14/2020

A torque converter is a type of fluid coupling device used to transfer engine power to the gearbox and driveline. A bypass clutch equipped in a torque converter assembly is a friction element which when fully engaged, can directly connect the engine to the gearbox. The torque converter is an important launch device in an automatic transmission which decouples engine speed from gearbox input speed while provides torque multiplication to drive the vehicle. During partial pedal launch, it is desired to engage the bypass clutch early and reduce the converter slippage in order to reduce power loss and achieve better fuel economy. However, engaging the bypass clutch early and aggressively may disturb the wheel torque and cause an unpleasant driving experience. This paper describes a multi-input multi-output (MIMO) control method to coordinate both engine and converter bypass clutch to simultaneously deliver desired wheel torque and reduce converter slippage. This control method leverages a

Xu, Yang, Chen, Weitian, Ford, Stuart, Liu, Pinzhi, Dai, Edward, Keller, Bret, Jiang, Hong

Optimized Control of Dynamical Engine-Start Process in a Hybrid Electric Vehicle

2020-01-026804/14/2020

Engine start while driving is one of the most typical and frequent work conditions for hybrid vehicles. Engine start has very significant impact on the driving comfort. Engine start, especially a dynamical engine start, have high control requirements regarding control time, torque output and riding comfort. In some hybrid transmissions such as P2, engine is cranked and synchronized through wet clutch slipping. Because clutch pressure control has time-varying delay and estimation precision of engine torque by ECU (Engine Control Unit) is poor, conventional PID controller is unable to meet the high requirements of control quality. A new control algorithm is proposed in this paper to cope with all these challenges. The new control algorithm is based on LADRC (Linear Active Disturbance Rejection Controller) and is improved through combination with Smith predictor and Adaline network. LADRC is adopted to reduce negative effects of poor precision of engine torque. Smith predictor is

Gao, Ji, Lou, Diming, Zhang, Tong

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.

Quantifying Engine Braking for Various Common Street Motorcycles

2020-01-088004/14/2020

Motorcycle engine braking was measured in each forward gear for a cross-section of typical street motorcycles. Using GPS data acquisition and video, deceleration relative to speed was examined. Motorcycle characteristics included various engine displacements and types of motorcycle. The data acquired will give more insight into the extent which engine braking is a factor for deceleration, a topic which has not been addressed in a peer-reviewed journal article to this date.

Jansen, Henricus, LeBlanc, Beau, Wilhelm, Christopher, Shaw, Tyler, Lowi, Alvin

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