Browse Topic: Transmission gears

Items (1,276)

Reduction of Gearbox noise by optimizing Gear micro geometry

2024-26-023401/16/2024

Vehicle noise level has to be maintained within the limit specified by Pass By Noise (PBN) standards to meet the regulatory requirements. Gearboxes and engines are the main sources of noise in a vehicle, owing to the mechanical and physical processes involved. The noise problem in transmission system is characterized by high amplitude acoustic signals, and the gear mesh noise can be indirectly estimated using the Transmission error parameter. Transmission error is defined as the difference between the actual position of the output gear and the position it would occupy if the gear drive were perfect, which can be attributed to various factors such as tooth profile errors, misalignment, and tooth deflections. A six-speed manual transmission commercial vehicle is observed to exhibit higher noise levels during the vehicle PBN test. The gearbox is modelled in Romax gearbox simulation software and the transmission error value is identified to be high. The micro geometry parameters lead

G R, Santosh Kumar, Ks, Dhianeshwar, Basim, K Mohammed

Investigation of Synchronizer Ring Failure in a Commercial Vehicle Transmission

2024-26-038301/16/2024

The commercial vehicles market is dominated with manual transmission, due to less ownership cost. Generally, the commercial vehicles are used in large numbers by the fleet owners. The transmission endurance life is very important to a vehicle owner. On the other hand, the driver fatigue can be reduced with smooth change process. The gear change process in a manual transmission is carried out with the help of the synchronizer pack. The crucial function of synchronizer pack in an automotive transmission is to match the speed of the target gear for smooth gear shifting. In a transmission the loose and the weakest part is the synchronizer ring. The failure of synchronizer affects smooth gear shifting and it also affects the endurance life of the transmission. The synchronizer ring can fail due to poor structural strength, synchronizer liner wear, synchronizer liner burning etc. The synchronizer liner burning is very difficult to analyze since the liner wear pattern are very uneven and the

Jamadade, Gajanan, K, Barathi Raja, Chatterjee, Soumik

Lubrication Effectiveness Determination for Wet-Sump Transmissions using Multiphase Computational Fluid Dynamics Modeling

2024-26-029801/16/2024

Wet-sump transmissions are widely used in heavy duty and medium duty vehicles. As these transmissions do not have a dedicated forced lubrication system, it is important that the gear train, shafts, and enclosure are designed appropriately so that enough oil splashes to critical locations to ensure sufficient lubrication. The lubrication effectiveness of such transmissions can be studied through detailed tests or numerical simulations. Often, the vehicle, and therefore the transmission, encounters some severe operating conditions, such as climbing on an incline, driving downhill, etc. Studying these conditions through tests is an expensive process and this imposes the need for an analysis first approach. In this paper, 3D multiphase Volume of Fluid (VOF) method is used to examine two such extreme cases: an 8-degree tilted installation of transmission in a vehicle, and an inclined condition of transmission during 10-degree uphill climb. By studying the oil volume fraction on gears and

r, Shamini, Sachdeva, Aniket, Handa, Joji, Sena, Carlos, Marson, Luigi

CAE Based Benchmarking of Shaft Deflection for Transmission Gear Rattle Noise

2024-26-024501/16/2024

Vehicle transmission gear rattle is one of the most critical NVH irritants for refined vehicles. It is perceived more dominantly in lower gears of vehicle running. It depends on various design parameters like Input torque amplitude & fluctuations, driveline torsional vibrations, gear micro & macro geometry, shaft flexibility, etc. Establishing exact contribution of each of these parameters to transmission rattle, thru experimental or simulation technique, is very challenging. Current paper explains the NVH CAE benchmark approach deployed to understand difference in rattle behavior of two transmission designs. Subjective and objective evaluation shows that one is better than the other for rattle noise. Paper focuses on simulation and comparison transmission shaft deflection as a measure of transmission rattle. FEA based nonlinear static simulations are carried out by applying torque induced forces at each of the gear contacts for all the gear engaged conditions. Simulated shaft

Bijwe, Vilas B., Kulkarni, Shriram, Vaidya, Rohit, Shah, Bhartendra

Integrated testing at lab from road by doing conversion and correlation between Subjective to objective assessment on ride comfort parameter of gear shifting quality in Two- wheeler.

2024-26-032701/16/2024

The evaluations of ride comfort in gear shifting have been known as one of the dominant factors for vehicle quality assessment. However, those factors have not been assessed and analyzed objectively in-depth in conjunction and integration with general ride and handling parameters. In recent, the criteria set by customer have changed on account of heightened expectations, resulting in a growing demand for enhanced ride comfort. the quality of gear shifting experienced by a customer is evaluated subjectively on road leads to difficulty in arriving inferences and taking decisions due to variation in responses of people on the same situation. This study is involved the process of conversion from subjective to objective assessment on gear shifting quality by identifying the objective parameters for contributing the quality of gear shifting feel. Measuring and analyzing those parameters like lever travel, lever effort, and noise while shifting during dynamic condition at vehicle level on

Manoranjan, R., K S, Sreekanth

Experimental Evaluation of Metro Rail Bogie Frame through Bench Testing

2024-26-032501/16/2024

Bogie frame is a main skeleton and structural member in railway system which is carrying all the loads such as Suspensions, Axles, wheels, car body, Motor, Gear box etc. The frame is subjected the exceptional and service stresses in Vertical, Longitudinal, Lateral and twist directions throughout the service life which should be withstand for a life span of 30 years without failure. The objective of this work is to estimate the structural integrity of the Metro rail bogie frame .This paper is the outcome of bench testing of metro rail bogie frame with the application of multiaxial loading in static and dynamic campaign through which stress data is collected with strain gauge sensors and correlated with the FEA results at design stage. This helps to verify and evaluate the design and validate the quality of metro rail frame as per the requirement specified in EN13749 European standard in early design stages.

Tormal, Uday Bapurao

Gearshift Simulator – Perceive Gearshift Feel at Early Development Stage

2024-26-029201/16/2024

One of the very first customer touchpoint in a vehicle is quality of gear shifting. Gearshift quality is perceived as a symbol of refinement, robustness of a vehicle. Globally, lot of efforts are taken to refine the gearshift quality. Design improvements in internal components of transmission, cable and shifter assembly, knob design iterations are carried out to arrive at optimum gearshift quality at the vehicle level. Current practice for this activity includes processes such as design modification, manufacturing of proto components, assembly of components and fitment in the vehicle. This vehicle is then instrumented with sensors and data acquisition units to capture the parameters which determine the gearshift quality. This is an iterative process which goes on until necessary refinement/improvement is achieved. This process requires investment of lot of time, efforts and the budget. This paper describes a virtual approach to arrive at optimum design of components. This paper gives

Tongaonkar, Yogesh Manohar, Patel, Hiral, Thambala, Prashanth, halingale, Amol

Analysis of Dynamic Characteristics and Load Sharing Performance of Electric Driven Planetary Gear System Based on Electromechanical Coupling Model

2023-01-701110/30/2023

Due to the multi-gear configuration and high integration of electric drive systems in electric vehicles, it is necessary to investigate the influence of drive motor torque fluctuation on the dynamic characteristics and load sharing performance of planetary gear transmission systems. Considering both motor torque fluctuation and internal excitations of the transmission system, a dynamic model of the electromechanical coupled system is established by combining the Maxwell motor electromagnetic model with the planetary gear dynamics model. Based on the proposed model, the dynamic characteristics, dynamic load performance and load sharing performance of the system considering motor torque fluctuation are analyzed, and the improvement of system load sharing performance due to sun gear floating is discussed. The results show that motor torque fluctuation leads to more complex dynamic response and causes the vibration displacement amplitude to more than doubled. Furthermore, the system

Guo, Fang, Li, Chen, Su, Jinzhan, Liu, Chao

Research on the control strategy of active gear shifting sound quality in the vehicle

2025-01-001905/05/2023

The active sound synthesis system of electric vehicles plays an important role in improving the sound perception and transmission of working condition information inside the vehicle. Nowadays, the active sound synthesis system inside the vehicle has become standard in electric vehicles of major Major automobile manufacturing plants to meet the user groups' demand for driving and riding experience. Starting from the existing in-vehicle active sound synthesis algorithm, this paper designs a gear shift control strategy suitable for all working conditions. During acceleration, in order to achieve the gear shifting effect, the motor speed signal is obtained to bias the speed at the shift point. During deceleration, in order to prevent a sudden increase at the shift point, the speed of the deceleration condition is linearly interpolated to make the shifting process of the deceleration condition smoother. During acceleration after deceleration, in order to avoid the uneven sound jump at the

xilong, zhou, Liu, Zhien, Xie, Liping, Lu, Chihua, Yu, Shangbo, GAO, XIANG, yongsheng, wang

Global Vehicle Vibration Enhancement Using Circular Force Technology

2025-01-001505/05/2023

In addition to safety advantages, sound and vibration are being utilized to enhance the driver experience in Electric Vehicles (EVs). Significant interest and investment continue to grow in utilizing interior and exterior sound for pedestrian safety and driver awareness of vehicle state, as well as enabling a unique personal EV audio experience for brand recognition both inside and external to the vehicle. Several automakers are also using audio to simulate virtual gear shifting and as well as manual transmissions in EVs. According to several automotive industry articles and market research, the audio enhancements alone, without the vibration that drivers are accustomed to in combustion engine vehicles, are not sufficient to meet the engagement, excitement, and emotion that driving enthusiasts expect. In this paper, we introduce the use of new automotive high-force compact light-weight circular force generators for globally shaking vehicles. The technology was developed originally for

Norris, Mark A., Orzechowski, JEFFREY, Sanderson, Brad, Swanson, Douglas, vantimmeren, Andrew

Comparison of sensing modes for stray-field-immune magnetic angle sensors

2022-01-075703/29/2022

Magnetic angle sensors play a major role in engine control, steering, and numerous other automotive applications like pedal, wipers and gear shift position sensing. With vehicle electrification, these sensors are increasingly exposed to parasitic magnetic stray fields. When shielding is not an option, a differential scheme is an alternative, where the sensor responds to magnetic field gradients. Two such schemes were previously introduced to reject stray fields to some degree. For these two modes, there are engineering trade-offs between the key performance parameters (noise, thermal drift, angular range). Often, these trade-offs are misunderstood by sensor users. This paper investigates these trade-offs by comparing the two stray-field-immune magnetic sensing modes. We use a single programmable integrated sensor supporting both modes for a direct comparison. The integrated sensor is designed for safety critical automotive applications. Two independent dies are integrated in the same

Lefebvre, Christopher, Mazzilli, Francesco, Laville, Arnaud, Bidaux, Yves, Close, Gael

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

Development of vehicle virtual test rig for powertrain dynamics characterization

2022-01-078303/29/2022

Simulating driveline NVH is a prominent and critical factor during new vehicle development. Driveline performance depends on accuracy of loads consideration and boundary condition of the vehicle systems. The evaluation of transient and steady state behavior of driveline system depends on participation from vehicle subsystems such as suspension, tire, body in combination with the driveline components like powertrain, flywheel, clutch, propeller shaft, differential and driveshaft. This work describes the development of a test rig in the virtual dynamic’s environment, consisting of virtual transmission and driveline assembled with full vehicle model. Roller rigs are developed and incorporated at the front and rear wheel ground integration points for excitation mechanism, it also accounts for tire slip factors and contact forces. A RWD ( rear wheel drive) vehicle model is considered for capturing major driveline transient and vibration event such as tip in/ tip out, gear shifting and

BHATTACHARYYA, INDRANIL

Experimental evaluation and VECTO simulations of a hybrid electric bus

2022-01-080703/29/2022

New heavy-duty vehicles are simulated with the Vehicle Energy Consumption Calculation Tool (VECTO) to certify their fuel consumption and CO2 emissions in the European Union. VECTO is planned to be utilized also for the certification of vehicles with hybrid electric powertrains, in all topological configurations spanning from P0 to P4 parallel systems as well as series hybrids. A development version of VECTO able to simulate these configurations is already available and was used for this study. In this work we have collected available measurement data from a specific P2 hybrid bus which was run in WHVC on the dyno as well as on the road and a vehicle model was created in VECTO. The VECTO Hybrid Controller was evaluated by comparing the measured and simulated decisions on utilizing the available power sources (fuel/stored electric energy), on regenerating braking and on gear shifting, on a step by step base as well as on a cycle average CO2 emissions result. The results show a good fit

Bitsanis, Evangelos, Broekaert, Stijn, Tansini, Alessandro, Fontaras, Georgios

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

Shift fork design using finite element simulations

2021-28-024410/01/2021

Shift fork and shift fork are key shifting element in manual and dual clutch transmission for smooth operations of gear shifting. One of the main criteria for robust design of shift fork and shift swing is stiffness symmetry. Stiffness symmetry ensures straight movement of sleeve onto hub and thus helps in achieving good shift quality. Stiffness symmetry also ensures equal load distribution across two or three pads of shift fork while operation. In this paper we intend to demonstrate finite element simulation driven design process to improve stiffness symmetry of shift fork and shift swing. Various parameter affecting stiffness symmetry are analyzed through design of experiment and selected best range for optimum design of shift fork and shift swing. Output of this study will be useful for improving any design of shift fork to meet different targets of stiffness symmetry for all automobile suppliers and manufactures.

PRAYAGA, GIRIDHAR KRISHNA, sahu, Deepak Kumar

Vibration analysis of Gear defects using Machine learning approach

2021-28-018210/01/2021

Gear drives are considered as the most effective transmission method in automobiles as well as in various industries because of its high efficiency, reliability and high velocity ratio. As a result, from its trustful usage, failure in any part may lead to a large and unpredictable production loss along with massive service cost and safety concerns. Periodic maintenance and condition monitoring are the only solution to avoid the above scenario. Vibration analysis are most sounded term in the fault detection due to its runtime condition monitoring and low cost. Nowadays, vibration analysis was off set to machine learning methods, which is a modern technique enable us the automation such that the system can learn from the input data and make decision with a nominal human interface were as conventional methods are highly operator dependent. Here in this study, the effectiveness of a machine learning based gear fault diagnosis system is studied. Gear defects like surface pitting

prasad SR, Vishnu, Poulose, Jasmine, Sadique, Anwar

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

Methodology To Derive RLD Based Durability Test Schedule For Gearbox Oil Seals

2021-26-046109/22/2021

Oil seal leakage is one of the major failure mode in gearbox / transaxle. Oil seal failures can be due to various reasons like high temperature, insufficient lubrication, failure due to external environment, incorrect fitment etc. Major reason for oil seal failure is insufficient oil flow inside gearbox when vehicle is running on gradient for long duration. When vehicle is running in hilly region, transmission will get incline leading to oil deficiency at one half of the transmission. Oil seal in this location will not get sufficient lubrication and will run dry. Also, there will be rise in local temperature at seal lip to shaft interface leading to failure of oil seal lip. Subsequently, oil leakage from transmission will start from this location when vehicle is running in different terrain. Due to continuous seepage, oil quantity in the transmission will get reduced and may lead to gear failure or seizure of bearing. Some OEM use transmission with transparent housing for lubrication

Uttamani, Rahul, Tendulkar, Vishveshvar, Navale, Pradeep, Kumar, Ravi, bhavikatti, Gururaj

Development of Closed Loop Power Recirculating Type Test Rig - Higher Torque Ranges

2021-26-049109/22/2021

In the past decades, many impressive progress has been made in the rig development for the gear validation. But, the challenges are to test the entire gear box for the improvement in the single gear alone to ascertain material quality or process improvement, that too with the higher torque range gear boxes, which requires huge investment and power consumption due to high capacity test rig / dynamometer. This paper deals with an experimental validation of the dynamic model for a gear pair test system, representative of a closed loop power recirculating type test rig. Being a closed loop, this system has its own uniqueness, that, it uses the low capacity prime mover, which considers the initial starting loop torque only, to cater the high power requirement in an efficient manner. The key intend of the development of this rig is to reduce the testing from system level to sub component level with low cost operation and more competence for the gears of high torque application. This also

Rajaraman, Manikandan, Srinivasan, Sriraman, Muthu kumar, Pandurangan, N, Gopi Kannan

Simulation based approach to study the effect of hypoid gear manufacturing variability on In-cabin noise

2021-26-027009/22/2021

With increase in demand for quieter product and reduction in masking noise, axle whine management plays a crucial role in the early product development process. Whine is tonal in nature and humans are more sensitive to tonal memory, hence this makes user to experience a very unpleasant ride which in turn results in bad product credibility. Dynamic mesh force excitation is the cause of the axle whine noise. Critical factors in consideration are micro-geometry design, operating loads and associated misalignment's, operating temperature & bearing pre-load, and the structural response that transfers mesh force excitation to the occupant's ear. Consideration of gear micro-geometry variability influence on driver ear noise is one of the most crucial aspect of robust axle whine management plan. This work demonstrates influence of gear manufacturing variability on hypoid gear transmission error, dynamic mesh force, pinion nose vibration and resulting axle whine noise in driver ear. This

Kolla, Kalyan Deepak, Paua, Ketan, Bhagate, Rajkumar, Vellandi, Vikraman, Jain, Saurabh Kumar

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

Ford engineered 2022 Bronco to give Jeep the willies

21AUTP08_0908/01/2021

Ford engineers refused to utter a single bad word about Jeep Wrangler during the course of the week-long 2022 Bronco media drive event in Austin, Texas. In fact, some among that gracious bunch admitted, ahem, that they may have owned and modified a Wrangler or two in their lifetimes. Jeep's profit-spinning 4x4 icon has that effect on competitors and fans alike. And it “has had this space to itself for decades,” noted Eric Loeffler, chief program engineer for U725, Ford's code for the new Bronco. About five years ago, Ford decided to unseat the Jeep's monopoly. The result is a modern take on another historic nameplate that finally brings Wrangler a truly serious competitor - and beats it in at least three key areas.

Brooke, Lindsay

Driver Classification of Shifting Strategies Using Machine Learning Algorithms

2020-01-224109/15/2020

The adequate dimensioning of drive train components such as gearbox, clutch and driveshaft presents a major technical task. The one of manual transmissions represents a special significance due to the customer’s ability of inducing high force, torque and thermic energy into the powertrain through direct mechanical interconnection of gearstick, clutch pedal and gearbox. Out of this, the question about how to capture behavior and strain of the components during real operation, as well as their objective evaluation evolves. Furthermore, the gained insights must be considered for designing and development. As a basis for the examination, measuring data from imposing driving tests are adduced. Therefore, a trial study has been conducted, using a representative circular course in the metropolitan area of Stuttgart, showing the average German car traffic. The more than 40 chosen drivers constitute the average driver in Germany with respect to age, gender and annual mileage. The used vehicle

Trost, Daniel, Ebel, André, Brosch, Erwin, Reuss, Hans-Christian

Test Procedure for Parking Stability of Motorcycles

J1101_202009 (Current)

09/09/2020

Side stands and center stands are designed to support stationary two-wheel motorcycles. This SAE Standard establishes procedures for determining parking surface loading and stability limits as follows: a The footprint pressure exerted on a horizontal parking surface by the stand. b The tilt angle of the parking surface at which tip-over occurs. c The tilt angle of the parking surface at which roll-off occurs.

Motorcycle Technical Steering Committee

The In-Depth PHEV Driveline Torsional Vibration Induced Vehicle NVH Response Study by Integrated CAE/Testing Methodology

2020-01-150706/03/2020

In this paper,an amesim 1-d refined driveline model, including detailed engine, damper, dual clutch, transmission, differential, motor, halfshaft, wheel, body, suspension, powertrain mounting and powertrain rigid body, was built up, off a p2.5 topology phev,to predict torsional vibration induced vehicle NVH response addressing differing driving scenarios,like WOT rampup,parking engine start/stop,ev driving to tipnin(engine start) then to tipout(engine stop).firstly,the torsional vibration modes were predicted,addressing differing transmission gear steps of hev/ev driving mode,and the critical modes could be detected,as such, caveats/measures could be applied to setup the modal alignment chart/warn other engineering section from the very start of vehicle development; secondly,secondly,the holistic operational testing,which defined plenty measurement points including rpm fluctuation at differing location of engine/transmission,spark angle,crank position,injection angle,valve timing,MAP

zhao, Qian, zhang, Li, jia, Jianning, WU, LIE, zhuang, Huimin, Yu, Hongzhi, lu, Shouwei, zhao, honghui, poduturu, Anil, jain, Swejal, carter, Steven

Analytical Rotordynamic Study of a High-Speed Gear Transmission System for Race Applications

2020-01-150206/03/2020

In motorsport power transmission systems, high-speed operation can be associated with significant rotordynamic effects. Changes in the natural frequencies of lateral (bending) vibrational modes as a function of spin speed are brought about by gyroscopic action linked to flexible shafts and mounted gear components. In the investigation of high-speed systems, it is important that these effects are included in the analysis in order to accurately predict the critical speeds encountered due to the action of the gear mesh and other sources of excitation. The rotordynamic behaviour of the system can interact with crucial physical parameters of the transmission, such as the stiffnesses of the gear mesh and rolling element-to-raceway contact in the bearings. In addition, the presence of the gear mesh acts to couple the lateral and torsional vibration modes of a dual-shaft transmission through which a torque flows. The relative interactions and effects of bearing and gear components can be

Friskney, Brett, Theodossiades, Stephanos, Mohammadpour, Mahdi, Friskney, Brett, Theodossiades, Stephanos, Mohammadpour, Mahdi

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

Parameter Optimization of Two-Speed AMT Electric Vehicle Transmission System

2020-01-043504/14/2020

At present, many electric vehicles are often equipped with only a single-stage final drive. Although the single-stage speed ratio can meet the general driving requirements of electric vehicles, if the requirements of the maximum speed and the requirements for starting acceleration or climbing are met at the same time, the power demand of the drive motor is relatively large, and the efficient area of the drive motor may be far away from the operating area corresponding to daily driving. If the two-speed automatic transmission is adopted, the vehicle can meet the requirements of maximum speed, starting acceleration and climbing at the same time, reduce the power demand of the driving motor, and improve the economy under certain power performance. This is especially important for medium and large vehicles. Therefore, this paper considers that the working torque and speed of the motor can be changed by optimizing the speed ratio of the transmission and changing the gear position so that

Cui, Jian, Tan, Gangfeng, Feng, Jia'ao, Tian, Zhongpeng, Agyeman, Philip

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

Research on Control Strategy Optimization for Shifting Process of Pure Electric Vehicle Based on Multi-Objective Genetic Algorithm

2020-01-097104/14/2020

With more and more countries proposing timetables for stopping selling of fuel vehicles, China has also issued a “dual-slope” policy. As electric vehicles are the most promising new energy vehicle, which is worth researching. The integration and control of the motor and gearbox have gradually become a hot research topic due to low cost with better performance. This paper takes an electric vehicle equipped with permanent magnet synchronous motor and two-gear automatic transmission without synchronizer and clutch as the research object. Through the action of the motor, gearbox and shift actuator in the shifting process, the whole vehicle dynamics is modeled in each stage of shifting, a method for determining a short-term driving style intensity factor for decision shifting is proposed, three evaluation indexes of the shift quality of electric vehicle are put forward, the control parameters affecting the shift quality are analyzed, and the mathematical relationship between the shift

Lei, Yulong, Zhang, Jingxu, Fu, Yao, Jia, Fuchun, Wang, Binyu

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

An FxLMS Controller for Active Control Engine Mount with Experimental Secondary Path Identification

2020-01-042404/14/2020

Active engine mounts (AEMs) notably contribute to ensuring superior performance of vehicle’s noise, vibration, and harshness. This paper incorporates a filtered-x-least-mean-squares (FxLMS) controller into the active control engine mount system to attenuate the transmitted force to the body. To avoid the error caused by substituting the load cell for acceleration transducer, the FIR model of the secondary path was obtained by experiment. Finally, a hardware-in-the-loop testing system is built to verify the performance of the active engine mount. It can be observed from the test results that the vibration is reduced notably after control, which demonstrates the effectiveness of the active engine mount and the controller in vibration attenuation.

Guo, Rong, Zhou, Ziwei, Chen, Hao

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

A Gear Shifting Indication Strategy of Eco-Driving Vehicle

2020-01-096604/14/2020

The current indication strategies of gear shifting indication system for manual transmission vehicles are developed based on the gear shifting strategies of the automatic transmission vehicles. In this paper, it is found that the gear shifting frequency of automatic transmission vehicles is significantly higher than that of manual transmission vehicles based on the collected driving data of several automatic transmission and manual transmission vehicles, which increases the fatigue of drivers. Aiming at this problem, this paper proposes an interval algorithm of gear shifting indication strategy based on the fuel consumption rate of engine, which uses genetic algorithm to process the data of fuel consumption rate to find the maximum and minimum values in the interval of torque and engine speed and adopts the interval algorithm to transform the search of least fuel consumption value into the seeking of optimal interval to avoid the shift busyness caused by the sudden change of fuel

He, Ren, Hu, Nannan, He, Ren, Hu, Nannan

Mathematical Analysis of Clutch Thermal Energy during Automatic Shifting Coupled with Input Torque Truncation

2020-01-096704/14/2020

A step-ratio automatic transmission alters torque paths for gearshifting through engagement and disengagement of clutches. It enables torque sources to run efficiently while meeting driver demand. Yet, clutch thermal energy during gearshifting is one of the contributors to the overall fuel loss. In order to optimize drivetrain control strategy, including the frequency of shifts, it is important to understand the cost of shift itself. In a power-on upshift, clutch thermal energy is primarily dissipated during inertia phase. The interaction between multiple clutches, coupled with input torque truncation, makes the decomposition of overall energy loss less obvious. This paper systematically presents the mathematical analysis of clutch thermal energy during the inertia phase of a typical single-transition gearshift. In practice, a quicker shift is generally favored, partly because the amount of energy loss is considered smaller. However, the analysis reveals that there is a critical input

Zhang, Yijing, Fujii, Yuji, Hippalgaonkar, Rohit, Cvok, Ivan, Ivanovic, Vladimir, Deur, Josko, Ranogajec, Vanja

Gear Shift Pattern Optimization for Best Fuel Economy, Performance and Emissions

2020-01-128004/14/2020

As the FTP-75 drive cycle does not have a prescribed gear shift pattern, automotive OEMs have the flexibility to design. Conventionally, gear shift pattern was formulated based on trial and error method, typically with 10 to 12 iterations on chassis dynamometer. It was a time consuming (i.e. ~ 3 to 4 months) and expensive process. This approach led to declaring poor fuel economy (FE). A simulation procedure was required to generate a gear shift pattern that gives optimal trade-off amongst conflicting objectives (FE, performance and emissions). As a result, a simulation tool was developed in MATLAB to generate an optimum gear shift pattern. Three different SUV/UV models were used as test vehicles in this study. Chassis dyno testing was conducted, and data was collected using the base and optimized gear shift patterns. Dyno test results with optimized gear shift pattern showed FE improvement of ~ 4 to 5% while retaining the NOx margin well above engineering targets. This labeling FE

Paulraj, Lemuel, Muthiah, Saravanan, S., Chidhanand

Feedback Control of Synchronizers for Reducing Impacts during Sleeve to Gear Engagement

2020-01-096004/14/2020

This paper presents a feedback control strategy aimed to reduce noise and wear during gearshifts in conventional and hybrid Dual Clutch Transmissions (DCT and DCTH) and Automated Manual Transmissions (AMT). The control strategy is based on a new dog teeth position sensor developed by China Euro Vehicle Technology AB and existing speed sensors in the transmission. During gear shifting, noise is generated by impacts between the sleeve teeth and the idler gear dog teeth after speed synchronization. Besides noise, these impacts are also responsible for delaying the completion of shift and contribute to wear in the dog teeth, hence reducing the lifespan of the transmission. The presented control strategy controls speed synchronization such that the impact between sleeve and idler gear dog teeth, before the start of torque ramp up, is avoided. Since drag torque is an important factor in speed synchronization, this paper also contains an algorithm to identify friction torque coefficient in

Piracha, Muddassar Zahid, Grauers, Anders, Hellsing, Johan

Sweating the details OF C8 DEVELOPMENT

20AUTP04_0304/01/2020

How GM's Corvette engineers tackled challenges in the move to a mid-engine architecture. Shifting 500 lb (227 kg) of engine mass rearward by 7.5 feet (2.3 m) and moving 300 lb (136 kg) of transmission components aft by almost three feet transformed the 2020 Chevrolet Corvette Stingray into a budding supercar. General Motors' motive behind adopting a mid-engine layout for the eighth-generation (C8) Corvette was to improve acceleration, braking and handling via substantially increased rear-tire loading. While numerous test-drive reviews and ‘Of the Year’ trophies mark that mission accomplished, there are lessons behind the hoopla: how GM engineers solved problems they encountered reinventing America's sports car. “Porsche was our primary benchmark, especially in reference to their PDK dual-clutch automatic transmission's overall dynamics,” revealed executive chief engineer Tadge Juechter, in an interview with SAE's Automotive Engineering. He said GM also purchased a Ferrari 458 for

WHAT WE'RE DRIVING

20AUTP04_0804/01/2020

For the Lincoln of my experience - and I'm not particularly young - I haven't been able to understand the “sell” of the brand. Low sales numbers and decades of declining prestige seemed to have long indicated a “cut your losses” argument for Ford to ditch its premium marque. But if the 2020 Aviator is the building block of things to come, there's hope. This all-new platform, sensibly shared with the volume-play Ford Explorer, returns Lincoln to the longitudinal engine/rear-drive layout that luxury vehicles are supposed to have. As a result, the Aviator is as responsive and athletic as you can expect a three-row, 16.5-foot-long crossover to be.

Nissan's 2020 Frontier gets new V6, 9-speed

20AUTP03_1503/01/2020

More transmission gears and greater engine horsepower should enliven the 2020 Nissan Frontier midsize pickup truck. “We're launching a new transmission and new engine in the current Frontier, and this powertrain will be the heart of the next-generation Frontier coming in 2021,” said Tiago Castro, Nissan North America's director of commercial business unit for pickup trucks, SUVs and vans. Castro spoke with Automotive Engineering during the 2020 Chicago Auto Show. Replacing the current standard 152-hp 2.5-L 4-cylinder and an optional 261-hp 4.0-L V6, the 3.8-L V6's first application is the 2020 Frontier. “We're getting 49 more horsepower with the new V6, which is best-in-class standard horsepower,” Castro said. The new 3.8-L engine's torque, rated at 281 lb-ft (381 Nm), matches the outgoing 4.0-L V.6.

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

Two-Speed Transmission Gear Shift Process Analysis and Optimization Using Genetic Algorithm

08-09-01-000101/16/2020

Electric Vehicle (EV) equipped with two-speed transmission has benefit in improving dynamic performance and saving battery consumption. However, during gear shift process, torque interruption and shift impact may lead to a bad shift quality. This work investigates gear shift process in an Automated Manual Transmission (AMT) configuration-based two-speed transmission. First of all, a typical gear shift process is analyzed. Parameters like motor speed, shift force, motor torque change rate, and speed difference between synchronizer and target engage gear are all included to find the relationships with shift duration. Then vehicle jerk is introduced as a criterion to evaluate shift impact. Besides, a comprehensive shift control strategy is developed. While keeping the output torque at wheels unchanged, the shift strategy also improved motor working efficiency after gear shift. Therefore, to determine an optimum shift strategy and achieve a balance among different parameters, Genetic

Cao, Zhan, Yang, Jiansen, Wang, Xinyu

Inside Tremec's SUPERCAR DCT

20AUTP02_0401/01/2020

To polish the 2020 mid-engine Corvette's driving prowess, GM and Tremec engineers joined forces to create a new and better automated transaxle. Explaining Corvette's move to one transmission for all buyers, global chief engineer Tadge Juechter notes, “Our customers began requesting a dual-clutch automatic transmission [DCT] several years ago. Following the introduction of the C7 Corvette in 2014, our take-rate for sticks [manual gearboxes] fell from 50 percent to less than 20 percent this year.” Searching the globe - read Europe - for a suitable DCT, Juechter's team found none with sufficient torque capacity to survive behind the lively LT2 6.2-L V8 planned for the all-new 2020 mid-engine edition of GM's reimagined sports car. To solve that dilemma, discussions began with Tremec, the Mexico City-based manufacturer which has supplied GM, Ford and FCA with manual transmissions for two decades. While Tremec had the expertise to make the mechanical components packed inside a dual-clutch

Understanding Base Oils and Lubricants for Electric Drivetrain Applications

2019-01-233712/19/2019

ABSTRACT The penetration of hybridization and electrification (HEV and EV) technology into automotive powertrain designs is an evolving trend resulting from global regulations intended to reduce transportation-related emissions of greenhouse gases and other pollutants and to improve vehicle fuel efficiency. In many HEV and EV hardware designs, drivetrain fluids have contact with the integrated electric motor (e-motor), which requires electrical and thermal properties to be considered in addition to traditional fluid properties. This paper discusses new insights gained around electrical and thermal properties of drivetrain fluids, with a specific emphasis on understanding the critical impacts of base oils (BOs). Electrical and thermal properties data as a function of temperature for a range of BOs as well as automatic transmission fluids are shared. We found that BOs and their viscosities play a critical role in cooling performance, while additives play a critical role in electrical

Kwak, Yungwan, Cleveland, Christopher, Adhvaryu, Atanu, Fang, Xinggao, Hurley, Susie, Adachi, Tsuneo

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

Automatic Transmissions - Schematic Diagrams

J647_201911 (Current)11/19/2019

The following schematic diagrams reflect various methods of illustrating automotive transmission arrangements. These have been developed to facilitate a clear understanding of the functional interrelations of the gearing, clutches, hydrodynamic drive unit, and other transmission components. Two variations of transmission diagrams are used: in neutral (clutches not applied), and in gear. For illustrative purposes, some typical transmissions are shown.

Automatic Transmission and Transaxle Committee

19AVEP11_0111/01/2019

After digesting some of the fascinating insights from surveys taken of automated-vehicle test riders - most of them first-timers - who participated in SAE International's Demo Days program (see pg. 31), you've got to conclude that the only thing predictable about the new-mobility landscape is its unpredictability. The year's not over yet and already it's been a wild ride.

Fuel Efficiency Improvement in Automatic Transmissions by Lockup Slip Methodology

2019-28-002910/11/2019

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

Performance Analysis of an Automated Manual Transmission Controller for Two-Wheeler

2019-28-012510/11/2019

This research paper presents controller development and its performance analysis for two wheeler. The comparison for different performance parameters is carried out with and without automated manual transmission (AMT) controller. The AMT considered in this case, includes a conventional manual transmission gear-box with conventional clutch pedal. It is equipped with clutch actuation with the help of linear actuator and the gear shifting using servo motor. The upshift and downshifting of the gears and the clutch actuation is done through the decisions of controller. The results generated during the engine dynamometer test are used as input creating two wheeler vehicle model using AVL cruise software. This vehicle model is used to predict vehicle performance. The vehicle performance results are validated with chassis dynamometer test data. The vehicle model is modified for generation of gear shifting plot. Also Gear shift program (GSP) is generated using the GSP generation module of AVL

Patil, Saurabh Sunil, Wani, Kiran Pralhad

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