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Viewing 1 to 30 of 2674
2015-01-14
Technical Paper
2015-26-0032
Raimund Ellinger, Edoardo Morra, Steffen Daum, Johannes Schauer, Gebhard Woentner
Best fuel efficiency is one of the core requirements for commercial vehicles in India. Due to the high Diesel prices this requirement is beside reliability and durability very important for end customers when deciding for a new truck or bus. Consequently it is a central challenge for commercial vehicle OEMs to optimize the whole powertrain, hence match the engine, transmission and rear axle specifications best to the defined application. The consequent high number of possible commercial powertrain combinations of engine, transmission and rear axle specifications requests for an efficient and effective development methodology based on system simulations. With this, the most suitable powertrain specifications, meeting all end customer requirements can be ensured.
2015-01-14
Technical Paper
2015-26-0130
Pradeep Kumar Singh
Gear noise and vibration in automobile transmissions is a phenomenon of great concern. Noise generated at the gearbox, due to gear meshing, also known as gear whine, gets transferred from the engine cabin to the passenger cabin via various transfer paths and is perceived as air borne noise to the passengers in the vehicle. This noise due to its tonal nature can be very uncomfortable to the passengers. Optimizing micro-geometry of a gear pair can help in improving the stress distribution on tooth flank and reducing the sound level of the tonal noise generated during the running of the gearbox when that gear pair is engaged. This technical paper contains the study of variation in noise level in passenger cabin and contact on tooth flank with change in micro-geometry parameters (involute slope and lead slope) of a particular gear pair. Further scope of study has been discussed at the end of the paper.
2015-01-14
Technical Paper
2015-26-0187
Venu Ganti, Yogesh Dewangan, Saurabh Arvariya, Shyamsananth Madhavan
Abstract Scuffing is an instantaneous failure which occurs when the meshed gear flanks undergo adhesive wear under extreme operating temperatures at medium- or high-speed conditions. It is one of the common failures in transmission gears, which tend to operate under long-duty cycle hours. The tip and the root regions often experience higher contact pressures because of the loading and surface curvature. These higher pressures, coupled with higher sliding velocities and heat generation, make the tip and root regions in the gear susceptible to scuffing. Gear geometry, material composition and lubricant properties influence scuffing. A balanced gear tooth design with lower sliding velocities is often chosen as an approach to avoid scuffing. However, in the current scenarios of transmissions with high power density requirements, achieving a balanced gear tooth design is rare. Lubricants with higher viscosity avoid scuffing, but have adverse effects on the transmission efficiency.
2014-11-11
Technical Paper
2014-32-0047
Mohamed El Morsy, Gabriela Achtenova
Abstract Using the PULSE platform for vibration analysis, which has been developed as an advanced solution for vibration measurements, the Robust Diagnostic Concept (RDC) was elaborated. The PULSE setup is designed to aid in fault diagnosis of a vehicle gearbox - the main part of a vehicle powertrain. Time Domain, Continuous Wavelet Transformation Technique (CWT), FFT and order analysis measurements are used for detection of an artificial pitting defect in a gear by tracking the gearbox response at accelerated speed and different loads. The test stand is equipped with three dynamometers; the input dynamometer serves as the internal combustion engine, the output dynamometers introduce the load on the flanges of the output joint shafts. The pitting defect is manufactured on the tooth side of the fifth speed gear on the intermediate shaft. The effect of temperature on the vibration measurements was also investigated to study its impact on the fault diagnosis.
2014-10-13
Technical Paper
2014-01-2891
Fuyuan Yang, Lei Du, Changsheng Yao, Jiaen Du, Ping Yu
Abstract This paper discusses whether it is possible to improve the motor efficiency by a two-speed transmission in an electric bus, and if so, to what extent. Based on the China Bus Urban Cycle, an 8-meter electric bus was studied via simulation in Matlab/Simulink. The comparison of motor efficiency between two different configurations was made: direct drive and drive through a two-speed transmission. In the first part of the simulation, the speed ratios of the two-speed transmission were chosen as 1.5 and 3.5. The motor efficiency was improved by 1.22% for driving and 1.66% for generation. To find out the maximum improvement and corresponding optimal speed ratio combination, scanning experiment of the lower ratio and upper ratio was conducted in the second part. As much as 1.66% improvement of driving efficiency and 2.20% of regenerating efficiency was achieved.
2014-10-13
Technical Paper
2014-01-2888
Abdelmajid Ait Taleb, Ali Chaaba, Mohamed Sallaou
Abstract The present paper aims at developing and implementing a systematic and simple algorithm for calculating the mechanical efficiency of the epicyclic gear trains operating as differential mechanism or speed reducer/multiplier. In this analysis, we consider the mechanical efficiency of the epicyclic gear train as a function of the configuration, speed in its three input / output shafts, and also with respect to the power-flow type. Results are compared to those obtained from other methods, available in the literature.
2014-10-13
Technical Paper
2014-01-2861
Shahnawaz Ahmed Khan, Snehal Dhongde
Abstract A small single cylinder 4 stroke gasoline engine varying capacity from 100cc to 500cc generally used for two wheelers has a wide range of load conditions. Such variation in load on engine demands variation in Transmission ratio at different vehicle speeds for optimum performance, drivability and Economy. A scooter has continuously variable transmission called as CVT which is generally centrifugally controlled with respect to engine speed as against that of series of manual gears used in motor cycle. The work aims at creating a mathematical model for controlling variation in transmission ratio of CVT by converting the generally centrifugally controlled CVT by electronic control. The objective is to implement the mathematical model with a novel electronic controlled CVT in a two wheeler engine for the improvement in performance. The mathematical model done through geometric calculations and modeling is discussed in details.
2014-10-13
Technical Paper
2014-01-2595
N. Karthikeyan, Anish Gokhale, Narendra Bansode
Abstract In scooters, the Continuously Variable Transmission (CVT) is used to transmit the power from the engine to the wheels. The CVT transmission consists of a two pulleys connected to each other through a belt. The change in the transmission ratio is achieved due to the change in the pulley diameters. A centrifugal clutch is attached to the rear pulley to transmit the power to wheels once the engaging engine speed is reached. The heat is generated due to the belt slippage and the engagement of the centrifugal clutch. Excessive heating may damage the belt, clutch and deteriorate its performance. The cooling of the belt, pulleys and the clutch is thus important for its safe operation. The cooling is achieved by the centrifugal cooling fan which forces the air over the belt, pulley and clutch. A clear understanding of the cooling system is important in designing the air flow path for clutch cooling of CVT housing.
2014-10-01
Journal Article
2014-01-9029
Uday Nayak, S Aravind, Sunil Aundhekar
Abstract The present competitive market scenario and customer requirements demand for improved NVH quality and to meet statutory norms without increased cost. When gears are used for power transmission, gear noise is of particular concern. The noise may be created due to harmonics of the rotating and meshing internal components. This has a significant effect on the overall vehicle sound quality. Various factors contribute to gearbox noise. Some of them include shaft misalignments, gear geometry, lubrication, bearings and loose mountings. Hence it is essential to study which factors contribute to the gearbox noise and to develop countermeasures for the same. Although a number of factors may contribute to gear noise as mentioned, the scope of this paper is limited to the effect of gear geometry alone on the gearbox noise.
2014-09-30
Technical Paper
2014-01-2399
Michael Sprengel, Monika Ivantysynova
Abstract A novel Blended Hydraulic Hybrid transmission architecture is presented in this paper with benefits over conventional designs. This novel configuration combines elements of a hydrostatic transmission, a parallel hybrid, and a selectively connectable high pressure accumulator using passive and actively controlled logic elements. Losses are reduced compared to existing series hybrid transmissions by enabling the units to operate efficiently at pressures below the current high pressure accumulator's pressure. A selective connection to the high pressure accumulator also allows for higher system precharge which increases regenerative braking torque and energy capture with little determent to system efficiency. Finally operating as a hydrostatic transmission increases transmission stiffness (i.e. driver response) and may improve driver feel in certain situations when compared to a conventional series hybrid transmission.
2014-09-30
Technical Paper
2014-01-2324
Antoine Delorme, Jason L. Robert, William Eli Hollowell, Andre M. Strobel, Jason T. Krajewski
Abstract In the recent years, Automated Manual Transmissions have become more popular for class 8 heavy trucks. Besides the benefits of smoother gear changes and reduced driver fatigue, AMTs can also greatly reduce fuel consumption by using optimized shifting strategies and advanced controls. The Detroit DT12 AMT demonstrated its ability to save fuel over a standard AMT, due in part to its eCoast feature. eCoast relies on intelligent and advanced electronic controls to safely allow the vehicle to coast on downgrades. While the engine is idling, the drag parasitic energy losses are decreased and the vehicle can fully use its momentum to travel further up and down hill. As one could expect, the type of route profile can greatly affect the fuel savings due to eCoast, since more hilly terrains might offer more opportunities to activate eCoast than flatter roads.
2014-09-30
Technical Paper
2014-01-2328
Jagjeet Singh, Gagandeep Singh
This paper introduces a new design for the synchromesh gear boxes, which serves dual purpose of economizing the production cost and time of the gears manufacturing and enhancing the shift experience by reducing the shift effort. This is achieved by making changes in the “Entry chamfers” which are the angles placed on the shift sleeve and gear dog teeth, and the “Back Taper Angle” also placed on the shift sleeve and gear dog teeth. In the new design the “Entry chamfer angles” is reduced from 120° (in the existing design) to 90° and is made “Un-symmetric” from “Symmetric”. This help in reducing the shift effort, hence enhancing the shift experience by making it smooth. Another change is the “Back Taper Angle”, which is eliminated from the sleeve and the gear dog teeth and is repositioned on the hub, keeping all other important design parameters like strut / insert design, gear cone angle, gear cone finish, number of cones, cone friction material the same.
2014-09-30
Technical Paper
2014-01-2335
Balakrishnan Natesan
Abstract Phosphorous is an important alloying element in powder metallurgy applications. It is used in Powder metal parts for effective Sintering, dimensional stability, improved machinability, corrosion resistance etc. However it does have some negative effects on properties of Powder metal parts. The purpose of the paper is to study the effect of phosphorous on Powder metal gear of Mix A and Mix B having identical composition differing only in phosphorous content. The samples were detailed on each stage, viz. sintering & Heat treatment. In addition two defective samples were studied to observe the extent to which phosphorous may deteriorate the Powder metal Gear.
2014-09-30
Technical Paper
2014-01-2371
Minghui Ren, Ying Wan, Hongyu Zheng
For city buses, especially hybrid electric buses, the requirements for the fuel economy and low noises are stricter, comparing with the momentum quality. Since hybrid electric buses sometimes run without the engine, the noises that the transmission makes become the major type. To get better fuel economy and lower noises, this paper focuses on optimizing the characteristics of the automatic mechanical transmission (AMT) in a hybrid electric city bus, and the studies are done as follows. Firstly, in order to reduce the fuel consumption, the transmission ratios are optimized by the co-simulation and optimization in CRUISE and MATLAB, with the limitation of the quality of driving momentum. Secondly, for the purpose of lightweight and lower transmission noise, multi-objective optimization based on reliability is applied in transmission geometric optimization design, the objective function are the smallest volume and the biggest transmission gear contact ratio of the transmission.
2014-06-30
Technical Paper
2014-01-2090
Joël Perret-Liaudet, Alexandre Carbonelli, Emmanuel Rigaud, Brice Nelain, Pascal Bouvet, C. Jacques Vialonga
Abstract The main source of excitation in gearboxes is generated by the meshing process, which generates vibration transmitted to the casings through shafts and bearings. Casing vibration generates leads to acoustic radiation (whining noise). It is usually assumed that the transmission error and variation of the gear mesh stiffness are the dominant excitation mechanisms. These excitations result from tooth deflection and tooth micro-geometries (voluntary profile modifications and manufacturing errors). For real cases, the prediction of noise induced by the Static Transmission Error (STE) remains a difficult problem. In this work, an original calculation procedure is implemented by using a finite element method and taking into account the parametric excitations and their coupling (Spectral Iterative Method, developed by the Ecole Centrale de Lyon).
2014-05-09
Journal Article
2014-01-9022
John O. Manyala, Todd W. Fritz
Electro-hydraulic actuated systems are widely used in industrial applications due to high torque density, higher speeds and wide bandwidth operation. However, the complexities and the parametric uncertainties of the hydraulic actuated systems pose challenges in establishing analytical mathematical models. Unlike electro-mechanical and pneumatic systems, the nonlinear dynamics due to dead band, hysteresis, nonlinear pressure flow relations, leakages and friction affects the pressure sensitivity and flow gain by altering the system's transient response, which can introduce asymmetric oscillatory behavior and a lag in the system response. The parametric uncertainties make it imperative to have condition monitoring with in-built diagnostics capability. Timely faults detection and isolation can help mitigate catastrophic failures. This paper presents a signal-based fault diagnostic scheme for a gearbox hydraulic actuator leakage detection using the wavelet transform.
2014-05-09
Journal Article
2014-01-9025
John O. Manyala
The emergence of tougher environmental legislations and ever increasing demand for increased ride comfort, fuel efficiency, and low emissions have triggered exploration and advances towards more efficient vehicle gearbox technologies. The growing complexity and spatial distribution of such a mechatronic gearbox demands precise timing and coordination of the embedded electronics, integrated sensors and actuators as well as excellent overall reliability. The increased gearbox distributed systems have seen an increased dependence on sensors for feedback control, predominantly relying on hardware redundancy for faults diagnosis. However, the conventional hardware redundancy has disadvantages due to increased costs, weight, volume, power requirements and failure rates. This paper presents a virtual position sensor-based Fault Detection, Isolation and Accommodation (FDIA), which generates an analytical redundancy for comparison against the actual sensor output.
2014-05-09
Journal Article
2014-01-9125
Byeong wook Jeon, Sang-Hwan Kim
This study was conducted to develop and validate a multidimensional measure of shift quality as perceived by drivers during kick-down shift events for automatic transmission vehicles. As part of the first study, a survey was conducted among common drivers to identify primary factors used to describe subjective gear-shifting qualities. A factor analysis on the survey data revealed four semantic subdimensions. These subdimensions include responsiveness, smoothness, unperceivable, and strength. Based on the four descriptive terms, a measure with semantic scales on each subdimension was developed and used in an experiment as the second study. Twelve participants drove and evaluated five vehicles with different gear shifting patterns. Participants were asked to make kick-down events with two different driving intentions (mild vs. sporty) across three different speeds on actual roadway (local streets and highway).
2014-05-05
Journal Article
2014-01-9024
Jean-Baptiste Gallo
Several drive cycles have been developed to describe heavy-duty class 8 truck tractor operations. However, regional delivery operations, consisting of a mix of urban and over-the-road driving using highways to access several delivery/pick-up sites in dense urban areas, have not been well described. With funding from the U.S. Army National Automotive Center, the High-efficiency Truck Users Forum (HTUF) developed two drive cycles in an effort to better describe the full range of Class 8 truck tractor operations, which in total consumed about 30 billion gallons of diesel in the United States in 2010. This paper describes the rational for and the process to develop two regional delivery drive cycles: HTUF Regional Delivery #1 and HTUF Regional Delivery #2. These cycles were developed from more than eight months of cumulative data collected on six diesel Class 8 truck tractors operating across North America and representing several types of truck vocations.
2014-04-01
Technical Paper
2014-01-1181
Md Abdul Quaiyum, Mohammed Ismail, Amir Fartaj
Abstract Channel diameter is one of the most important parameters of a heat exchanger especially for a highly viscous fluid-flow. Narrow channel heat exchangers are believed to have better energy efficiency due to elevated heat transfer characteristics. Heat transfer and Fluid-flow behaviors of Automatic Transmission Fluid (ATF) have been experimentally investigated in a closed loop integrated thermal wind tunnel test facility using wavy finned Minichannel Heat Exchanger (MICHX). The experiment was conducted by varying the ATF Reynolds number from 3 to 30. The flow friction factors in minichannel were evaluated. For a fully developed laminar flow the friction factors were evaluated considering fluid viscosity effects due to temperature variation. The flow correlated with a Poiseuille equation while friction factors were analyzed considering constant property ratio. However, it showed different correlation when considered variable property ratio.
2014-04-01
Technical Paper
2014-01-1082
Ayman Moawad, Aymeric Rousseau
Abstract Manufacturers have been considering various technology options to improve vehicle fuel economy. One of the most cost effective technology is related to advanced transmissions. To evaluate the benefits of transmission technologies and control to support the 2017-2025 CAFE regulations, a study was conducted to simulate many of the many types of transmissions: Automatic transmissions, Manual Transmission as well as Dual Clutch Transmissions including the most commonly used number of gears in each of the technologies (5-speeds, 6-speeds, and 8-speeds). Different vehicle classes were also analyzed in the study process: Compact, Midsize, Small SUV, Midsize SUV and Pickup. This paper will show the fuel displacement benefit of each advanced transmission across vehicle classes.
2014-04-01
Technical Paper
2014-01-0182
Raunak Santosh, Vijayakumar Chekuri
Abstract Rapid growth in the Indian economy has led to new market trends for commercial vehicles. Customers now expect high levels of comfort from all tactile points in a truck cabin; the gear lever knob is frequently used and its reactions greatly influence how a driver perceives Gear Shift Quality (GSQ) and thereby vehicle quality. The subjectivity of human perception is difficult to measure objectively; therefore this paper represents an objective methodology to correlate customer feedback of gearshift reactions. For the attribute evaluation of a set of intermediate commercial vehicles; detailed subjective appraisals were conducted by expert level assessors for GSQ sub-attributes, and a consecutive objective measurement was performed to investigate and substantiate these vehicle assessments.
2014-04-01
Technical Paper
2014-01-1717
Robert Lloyd
Abstract A hydro-mechanical transmission is described that approximates the “gearing” performance of a continuously variable transmission and incorporates all functions required for hydraulic regenerative braking. Other characteristics such as efficiency, noise, and responsiveness, match or exceed that of present day conventional automatic transmissions. Performance and physical sizing are shown for passenger vehicle, bus and truck transmissions.
2014-04-01
Technical Paper
2014-01-1718
Amit Sandooja
Abstract In a transmission for Automobiles, the driver's comfort of smooth shifting and selection of gears is a major concern for the transmission designer. To achieve this comfort, lot of work and improvement has been done in the past few years and still some more improvements are in continuation by the automobile manufacturer. Apart from the smooth shifting and selection of gears while driving, the safety of the driver is also a major concern for the vehicle manufacturer. This paper relates to a safety Interlock mechanism of vehicle gear shifter selector lever to a drive position, until a predetermined condition is satisfied. There are various gear shift pattern exists in the vehicles, which depends upon the number of gears in the gearbox. Generally, two types of gear shift pattern are commonly used in commercial vehicles. 1st-2nd, 3rd- 4th, 5th-6th, Rev and Rev-1st, 2nd-3rd, 4th-5th, 6th.
2014-04-01
Technical Paper
2014-01-1719
Abhijeet Pingale
Advancements in engine technology have increased overall torque rating of engine and demanded further improvement in transmissions to sustain higher input torque. Conventional brass synchronizers have proved inadequate for these torque and gear inertia. It becomes necessary to use advanced material science and enhanced technology to synchronizer capabilities. Multi-cone compact synchronizer with carbon composite friction material technology has been tested successfully for these more demanding applications. This paper will focus on some of the key challenges in modern synchronized transmission, and way forward to address those. Some of the key areas delivering highest impact are being discussed. A combination of various techniques has enabled a significant reduction in overall transmission length along with enhancement in shift effort, life and overall performance.
2014-04-01
Technical Paper
2014-01-1757
Marco Mammetti, Marina Roche Arroyos
Abstract Over recent years IDIADA has developed several prototype electric vehicles as well as testing a number of electric powertrain configurations. Generally the electric motor output shaft delivers the torque to the transmission under a considerable level of high-frequency load variation and with noticeable torque irregularities that must be smoothed out in order to fulfill general NVH targets. This paper deals with the development phase of a prototype vehicle in which a specific testing activity was carried out to improve the overall NVH behavior of the powertrain. For this purpose, the mechanism of energy transference from the current to the motor and from the motor to the downstream driveline components was deeply characterized. The activity was aimed at smoothing the abrupt change in torque delivery and limiting the transfer of torque irregularities from the motor to the transmission.
2014-04-01
Technical Paper
2014-01-1752
Ewan Pritchard, Richard Gould, Richard Johnson
Abstract The introduction of parallel post transmission hybrid electric vehicles has demonstrated a limitation of previous mathematical models of the hydraulic torque converter. Earlier models developed by Hrovat and Tobler (2) and Kotwicki (4) in the 1980's only covered the cases of the below coupled and coupled states without anticipating the need to analyze the converter in the overrunning case. This study develops the relations for the overrunning case, allowing the reader to establish accurate predictions or computer simulations of the flow, torque, and speeds that will be result in the case of a post transmission hybrid system. Without additional measures, these post transmission hybrid systems will generate large fluid losses in the torque converter.
2014-04-01
Technical Paper
2014-01-1756
Miguel De la Cruz, Stephanos Theodossiades
Abstract In this paper, a direct correlation between transmission gear rattle experiments and numerical models is presented, particularly focusing on the noise levels (dB) measured from a single gear pair test rig. The rig is placed in a semi-anechoic chamber environment to aid the noise measurements and instrumented with laser vibrometers, accelerometers and free field microphones. The input torsional velocity is provided by an electric motor, which is controlled by a signal generator, aiming to introduce an alternating component onto the otherwise nominal speed; thus, emulating the engine orders found in an internal combustion engine. These harmonic irregularities are conceived to be the triggering factor for gear rattle to occur. Hence, the rig is capable of running under rattling and non-rattling conditions. The numerical model used accounts for the gear pair's torsional dynamics, lubricated impacts between meshing teeth and bearing friction.
2014-04-01
Technical Paper
2014-01-1751
Daisuke Okamoto
Abstract 1 Recently, automatic transmissions (AT) have been developed to have more step numbers to improve their power transmitting efficiency for better fuel consumption. Due to the increased steps, the frequency of engaging and disengaging of wet clutches and brakes in an AT is getting higher. And then the required characteristics for a clutch is not only to make a smooth engagement but also to react smoothly in the process of disengagement, due to the clutch-to-clutch type shift strategy. Although there have been many researches on the engaging process, however, few have been done for the clutch behavior in the disengagement process so far. Regarding the process of disengagement of a clutch, a phenomenon described below has been observed and reported which leads to a kind of shock during a shift.
2014-04-01
Technical Paper
2014-01-1740
Jiageng Ruan, Paul Walker
Abstract Regenerative braking energy recovery bears significance in extending the driving mileage of electric vehicles (EVs) while fulfilling real-time braking demands. Braking energy strategy plays a significant role in improving the regenerative braking performance and ensuring braking safety. This paper presents a regenerative braking energy recovery strategy for an example EV with a two-speed Dual Clutch Transmission (DCT). The two-speed DCT, with simple structure, can effectively extend the active vehicle speed-range for regenerative braking. Meanwhile, a shifting strategy is proposed for the DCT, working with the presented braking energy recovery strategy, to optimize the brake force distribution between front and rear wheels, motor and friction brake force. The EVs' model with the proposed regenerative braking strategy and the optimal shifting schedule was established and implemented in Matlab/Simulink.
Viewing 1 to 30 of 2674