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Viewing 1 to 30 of 2667
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. The efficiency of the cooling system depends on the quantity and direction of flow.
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. The mathematical model is compared with the actual testing data to validate the calculations and results.
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. Moreover, two 3-D maps (drive and regenerate) were derived, in which X-axle and Y-axle represented upper gear ratio and lower gear ratio respectively and Z-axle for the improvement of efficiency.
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.
2014-10-01
Technical Paper
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. This paper offers an experimental investigation of reducing the noise levels in Ashok Leyland gearbox by modifying the gear tooth profile on one of the gear trains in order to meet the futuristic noise statutory norms.
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.
2014-09-30
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. The new design ensures that the change in back taper angle position does not compromise its function of avoiding the “Gear jump out”.
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
2014-01-2399
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. To explore the novel blended hybrid architecture six transmissions were modeled and simulated.
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. In addition, when combined with different vehicle and driving parameters such as vehicle weight and driver desired cruise set speed, the fuel consumption reduction of eCoast is always there, but becomes a more complicated function.
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). The procedure is based on a modal approach developed in the frequency domain, particularly efficient to analyze systems having many degrees of freedom.
2014-05-09
Technical Paper
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. The novelty of the work is the development of a high fidelity leakage fault detection as low as 0.128 lit/min.
2014-05-09
Technical Paper
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. The proposed FDIA scheme has been validated experimentally using an electro-hydraulic test rig and the gearshift simulation model, including the non-linear hydraulic actuator dynamics.
2014-05-09
Technical Paper
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). After each event, participants were asked to complete the rating of the four descriptive terms as well as a comprehensive rating on the gear-shifting event.
2014-05-05
Technical Paper
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. The HTUF Regional Delivery drive cycles fill an important gap in understanding and describing the full range of Class 8 truck tractor operations.
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
2014-01-1166
Yao Fu, Yulong Lei, Sun Shaohua, Huabing Zeng, Ke Liu, Yuanxia Zhang
Abstract After the analysis of shift quality evaluation methods of stepped automatic transmission, the evaluation indexes of shift quality have been established based on power-on up-shift of DCT (dual clutch transmission). Shift quality objective evaluation method of DCT based on TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) model is proposed. Taking the ideal shift process as reference, the shift quality evaluation model based on absolute ideal solution is developed. A comparison with the subjective evaluations shows that the proposed method is in good agreement with the traditional subjective evaluation method. The TOPSIS model provides a new shift quality evaluation approach and thinking for stepped automatic transmission.
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. Dynamic and Static testing techniques were used to measure GSQ parameters like efforts during gear shift/select, feel of different phases of gear engagement /selection, gate definitions and lever travels; this helped in formulating objective metrics that can be used to create a definition of GSQ in a vehicle segment and an objective methodology to assess the same.
2014-04-01
Technical Paper
2014-01-0407
Hiroyuki Kitajima, Takanori Ide, Juan Leiva, Brian Watson, Shrinivas Lankalapalli
Abstract A design process to improve the structural performance under contact conditions of automatic transmission of vehicles is presented. The proposed process uses newly developed nonlinear contact optimization techniques. Additionally, useful structural optimization techniques such as 3D topography and the beta method are described. As a demonstrative problem, we consider the improvement of a 6- speed AISIN FWD automatic transmission which is subjected to static loadings and nonlinear contact conditions.
2014-04-01
Technical Paper
2014-01-0674
Byungchan Lee, Dohoy Jung, John Myers, Jae-Hoon Kang, Young-Ho Jung, Kwang-Yeon Kim
Abstract A numerical study is conducted to investigate the effect of changing engine oil and automatic transmission fluid (ATF) temperatures on the fuel economy during warm-up period. The study also evaluates several fuel economy improving devices that reduce the warm-up period by utilizing recycled exhaust heat or an electric heater. A computer simulation model has been developed using a multi-domain 1-D commercial software and calibrated using test data from a passenger vehicle equipped with a 2.4 / 4-cylinder engine and a 6-speed automatic transmission. The model consists of sub-models for driver, vehicle, engine, automatic transmission, cooling system, engine oil circuit, ATF circuit, and electrical system. The model has demonstrated sufficient sensitivity to the changing engine oil and ATF temperatures during the cold start portion of the Federal Test Procedure (FTP) driving cycle that is used for the fuel economy evaluation. The results from the study indicate that the potential fuel economy improvement during the driving cycle is 7.3 % at 24°C ambient temperature, and 20.1 % at −6.7°C.
2014-04-01
Technical Paper
2014-01-0660
V. Sundaram, Tharunnarayanan Arthanari, Sathish Kumar S
Abstract The performance of the Transmission Oil Cooler (TOC) is influenced significantly by the TOC plumbing lines which transmit the oil from transmission system to the oil cooler and back. Designing the optimum TOC plumbing line with lesser pressure drop is the need of the hour considering the complex nature of the vehicle packaging. Reducing the pressure drop increases the oil flow rate through the transmission which results in optimum performance. Improved transmission efficiency in turn shall improve the engine efficiency and performance. The improvements obtained from increased transmission and engine efficiency shall result in an overall increase in vehicle fuel economy. Optimization solutions are required in the early product development cycle where the components are not readily available and/or are prohibitively expensive to do testing. In such scenarios, one-dimensional (1D) simulations shall be employed to compute the pressure drop for faster and economical solutions. In this paper, the approach of creating a modeling tool for TOC plumbing line pressure drop is discussed.
2014-04-01
Technical Paper
2014-01-0578
Karthikeyan N, Anish Gokhale, Narendra Bansode
Abstract The Continuous Variable Transmission (CVT) in scooters is used to transmit the power from the engine to the wheels. The CVT transmission consists of a drive pulley and a driven pulley connected to each other through a belt. The centrifugal clutch is attached to the rear pulley which transmits the power to the wheel. The engagement and disengagement of the clutch generates heat and friction heat is generated between the belt and pulley, thereby requiring continuous external cooling for its safe operation. A centrifugal fan is employed for cooling of the CVT belt. Since the cooling fan takes air from atmosphere, there is always a possibility of dust from the atmosphere entering the system, which might cause wear of pulley and belt, thereby decreasing the performance of the transmission system. The objective of the work is to analyze the dust ingress pattern in to CVT housing. The work aims at simulating the possible conditions for dust entry into the CVT housing for a complete scooter and the study of different design proposals to minimize the dust entry without compromising the cooling requirement of CVT.
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. A numerical analysis on friction factor for single serpentine MICHX did not follow the Poiseulle law for both cases of constant property ratio and variable property ratio.
2014-04-01
Technical Paper
2014-01-1799
Xingxing Zhou, Paul Walker, Nong Zhang, Bo Zhu, Jiageng Ruan
Abstract This paper mainly studies the power losses in a refined two-speed dual clutch transmission which is equipped in a electric vehicle test rig. Both numerical and experimental investigations are carried out. After theoretical analysis of the power losses original sources, the developed model is implemented into simulation code to predict the power losses. In order to validate the effectiveness of the proposed model, results from experimental test are used to compare the difference the simulation and test. The simulation and test result agree well with each other. Results show that the power losses in the two-speed are mainly generated by multi-plate wet clutch drag torque and gear churning loss.
2014-04-01
Technical Paper
2014-01-1793
Chen Wang, Zhiguo Zhao, Tong Zhang, Xianjun Dai, Xiyue Yuan
Abstract Several types of power-split hybrid transmissions are outlined and the strengths and weaknesses of typical compound power-split prototype designs are summarized in this paper. Based on an modified Ravigneaux gear set, a novel compound power-split hybrid transmission with compact mechanical structure is presented, its dynamic and kinematic characteristics in equations and operating modes are described, and then equivalent lever diagrams are used to investigate the proposed compound power-split device. Control strategies in different operating modes are discussed with the simplified combined lever diagram, and a global optimization method is implemented to find the optimum operation point for the hybrid powertrain. To evaluate the fuel economy of a hybrid car equipped with this hybrid transmission, a forward powertrain simulation model is developed and real vehicle performance tests are conducted in the chassis dynamometer. Simulations and test results show that the proposed hybrid transmission can improve the efficiency of the powertrain and demonstrate lower fuel consumptions than the corresponding conventional vehicle.
2014-04-01
Technical Paper
2014-01-1778
Namdoo Kim, Aymeric Rousseau, Henning Lohse-Busch
Abstract As a result of increasingly stringent regulations and higher customer expectations, auto manufacturers have been considering numerous technology options to improve vehicle fuel economy. Transmissions have been shown to be one of the most cost-effective technologies for improving fuel economy. Over the past couple of years, transmissions have significantly evolved and impacted both performance and fuel efficiency. This study validates the shifting control of advanced automatic transmission technologies in vehicle systems by using Argonne National Laboratory's model-based vehicle simulation tool, Autonomie. Different midsize vehicles, including several with automatic transmission (6-speeds, 7-speeds, and 8-speeds), were tested at Argonne's Advanced Powertrain Research Facility (APRF). For the vehicles, a novel process was used to import test data. In addition to importing measured test signals into the Autonomie environment, the process also calculated some of the critical missing signals, such as gear ratio and torque converter lockup.
2014-04-01
Technical Paper
2014-01-1772
Daiki Saegusa, Shinji Kawai
Abstract An analytic technology able to rapidly and accurately predict oil flows and churning torque in a transmission has been developed. The new method uses the finite difference method for analysis; with regard to wall boundaries it reproduces the shapes of physical objects by imparting boundary information to cells. This has made it a simple matter to treat the rotation and meshing of the gears, which form oil flows, and has also reduced the calculation cost. Tests of single-phase and multi-phase flows and churning torque were conducted in order to verify the accuracy of the new method. Calculation results for the flow velocity fields produced by rotating bodies, the trajectory of oil, and the behavior of the surface of the fluid displayed a good correlation with test results. Considering air entrainment in the oil, the ability of the method to reproduce these phenomena at high speeds of rotation was also increased. The method also displayed good reproduction of changes in churning torque produced by differences in the speed of rotation of the gears.
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. In the first type of gear shift pattern, neutral gear is placed in between 3rd-4th gear and reverse gear is separate.
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
2014-01-1727
James Gramling
Abstract It is very important to note that most present-day CVT's drive with a friction element. Unlike gears that can be produced with any size necessary for the torque load they must transfer, CVT's are limited in torque capacity and are only marginally suitable for small vehicle applications. A system is described using two variable-inertia flywheels to not only supply the heavy torque requirements during acceleration of a vehicle but also operate in reverse capturing the otherwise wasted decelerating torque (I.E. braking torque). This system (called Kinetic Energy Power Transmission System or KEPTS) provides all of the documented benefits of the use of an IVT for motor vehicle acceleration and also incorporates regenerative braking. The significance of the system is that besides providing a complete KERS (kinetic energy recovery and storage) system, all accelerating and braking torque is provided by the two variable-inertia flywheels, thus allowing the main motive engine (ICE, electric traction motor, gas turbine, etc.) to operate at a fixed angular velocity (rpm) isolated from large torque variances, and the CVT elements can be minimized in size (I.E. low-torque).
Viewing 1 to 30 of 2667