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Viewing 1 to 30 of 4774
2017-10-08
Technical Paper
2017-01-2358
Michael P Gahagan
Abstract The automotive vehicle market has seen an increase in the number of hybrid electric vehicles (HEVs), and forecasts predict additional growth. In HEVs, the hybrid drivetrain hardware can combine electric motor, clutches, gearbox, electro-hydraulics and the control unit. In HEV hardware the transmission fluid can be designed to be in contact with an integrated electric motor. One transmission type well-suited to such hybridization is the increasingly utilized dual clutch transmission (DCT), where a lubricating fluid is in contact with the complete motor assembly as well as the DCT driveline architecture. This includes its electrical components and therefore raises questions around the suitability of standard transmission fluids in such an application. This in turn drives the need for further understanding of fluid electrical properties in addition to the more usually studied engineering hardware electrical properties.
2017-10-08
Technical Paper
2017-01-2355
Yungwan Kwak, Christopher Cleveland
Abstract Due to its simplicity and fuel economy benefit, continuously variable transmission (CVT) technology has gained a lot of attention in recent years. Market penetration of CVT technology is increasing rapidly compared to step-type automatic transmission technology. OEMs, Tier 1 suppliers, and lubricant suppliers are working to further improve the fuel economy benefit of CVTs. As a lubricant supplier, we want to understand the effects of fluid properties on CVT fuel economy (FE). We have formulated fluids that had KV100 ranges from 2-4 cSt to 7-9 cSt with various types and viscosities of base oils. Wide ranges of viscosity indexes, steel-on-steel friction, and other properties were tested. Full vehicle fuel economy tests were performed in a temperature controlled environment with a robotic driver. The test revealed that there was more than 3% overall FE variation compared to a reference fluid.
2017-10-08
Technical Paper
2017-01-2205
Velmurugan M A, MahendraMohan Rajagopal
Abstract Agricultural tractors are often subjected to various applications like front end loading work, cultivation work, where frequent forward and reverse gears are needed. Most of Indian agricultural tractors are equipped with mechanical transmission system which demands repeated clutching and de-clutching operation for such applications resulting in increased operator fatigue and lesser productivity. Also need of electronics in Indian agricultural industry for better farm mechanization is growing high. This research work depicts development of electronic bi-directional shifting (power shuttle) control design and calibration for farm vehicle fitted with wet clutch transmission. This research also reduces operator fatigue via frequent directional shift through electronic transmission. The control system is designed without any electronic interfacing with engine and also provides clutch-less gear shifting and auto-launch which offers ease to drive even for novice driver.
2017-10-08
Technical Paper
2017-01-2462
Ruipeng Zhang, Kaichuang Meng
Abstract Due to the increase of mining production and rising labor costs, manufacturers of construction and mining equipment are engaged in developing large tonnage mining truck with good dynamic performance and high transport efficiency. This paper focuses on the improvement of the dynamic performance of a 52t off-highway dump truck. According to the characteristics of its operating cycle, electric auxiliary drive system is installed in the front axle aiming at improving the utilization rate of ground adhesion. The new all-wheel drive hybrid electric system makes it possible for dump truck transports at a higher velocity. Both the conventional dump truck model and the new all-wheel drive hybrid truck model are built based on the AVL-Cruise platform. Meanwhile, under the premise of enough dynamic performance, fuel consumption can be minimized by collaborative optimization in Isight.
2017-10-08
Technical Paper
2017-01-2460
Wenbin Liu, Qiang Song, Yiting Li, Wanbang Zhao
Abstract In this paper, a novel driver model is proposed to track vehicle speed in MIL (Model-in-the-Loop) test system, which has structural consistency with HIL (Hardware-in-the-Loop) test system. First, the MIL test system which contains models of driver, vehicle and test bench is established. Second, according to the connections of the established models in Matlab/Simulink environment, the vehicle speed is calculated in vehicle model. Emphatically, through the deviation between driving cycle speed and calculated vehicle speed, PI controller in driver model adjusts the vehicle speed to ideal point through sending the torque command to drive motor, the ILC (Iterative Learning Control) controller modifies and stores P value of PI controller. Then, in order to obtain the better modification of PI controller, iterative learning control algorithm is deeply researched in term of types and parameters.
2017-10-08
Technical Paper
2017-01-2435
Jian Ji, BoZhou He, Lei Yuan
Abstract It is well-known that, compared with automatic transmissions (ATs), continuously variable transmission (CVT) shows advantages in fuel saving due to its continuous shift manner, since this feature enables the engine to operate in the efficiency-optimized region. However, as the AT gear number increases and the ratio gap narrows, this advantage of CVT is challenged. In this paper, a comparative study on fuel economy for a CVT based vehicle and a 9-speed automatic transmission (AT) based vehicle is proposed. The features of CVT and AT are analyzed and ratio control strategies for both the CVT and 9-speed AT based vehicles are designed from the view point of vehicle fuel economy, respectively. For the 9-speed AT, an optimal gear shift map is constructed. With this gear shift map, the optimal gear is selected as vehicle velocity and driving condition vary.
2017-10-08
Technical Paper
2017-01-2437
Renjith S, Vinod Kumar Srinivasa, Umesh Venkateshaiah
Abstract The jet lubrication method is extensively used in the constant mesh high performance transmission system operating at range of speeds though it affects mechanical efficiency through spin power loss. The lubrication jet has a key role to maintain the meshing gears at non-fatal thermal equilibrium by effectively dissipating the heat generated to the surrounding. Heat transfer coefficient (HTC) is the indicator of the thermal behavior of the system, which provides great insight of efficient lubrication system that needs to be employed for prescribed type of transmission. In this study, a segment of the transmission unit which constitutes a gear pair is used for the simulation. Parametric study is carried out by considering the critical parameters affecting the thermal performance such as lubrication jet flow rate and rotational motions of the gears with speeds and temperatures.
2017-10-08
Technical Paper
2017-01-2439
Srinivasan Paulraj, Saravanan Muthiah
Abstract Poor clutch life is a major issue for some light commercial vehicle models. Clutch overheating is the primary cause for clutch failure. Some of the reasons include inappropriate gear selection by the driver, poor low-end dynamic torque availability from an engine, heavy stop and go traffic, vehicle overloading resulting in excessive clutch slippage especially in gradients, riding of the clutch pedal by the customer etc. These situations lead to a high thermal energy dissipation at the clutch, increasing clutch wear and in extreme conditions leading to not only poor shift quality but also eventual clutch failure. Unfortunately, it is not practical to monitor clutch temperature in a production vehicle due to high costs or technical challenges involved. This paper describes 1-D thermal modeling of single plate dry clutch typically used in passenger car/truck and bus applications.
2017-10-08
Technical Paper
2017-01-2441
Zhao Ding, Li Chen, Chengliang Yin, Jian Yao, Chunhao Lee, Farzad Samie
Abstract Rotating clutches play an important role in automatic transmissions (AT), dual-clutch transmissions (DCT) and hybrid transmissions. It is very important to continually improve the transmission systems in the areas such as simplifying actuator designs, reducing cost and increasing controllability. A new concept of electrical motor driven actuation using a wedge mechanism, a wedge clutch, demonstrates potential benefits. This wedge clutch has the characteristics of good mechanical advantage, self-reinforcement, and faster and more precise controllability using electrical motor. In this paper, a new rotating wedge clutch is proposed. It presents a challenge since the motor actuator has to be stationary while the clutch piston is rotating. A new mechanism to connect the motor to the wedge piston, including dual-plane bearings and two mechanical ramp linkages, is studied. The design and verification of the physical structure of the actuator are discussed in detail in the paper.
2017-10-08
Technical Paper
2017-01-2442
Bingqing Xiao, Wei Wu, Jibin Hu, Shihua Yuan, Chenhui Hu
Abstract The prediction of temperature distribution and variation of oil-cooled sliding disk pair is essential for the design of wet clutches and brakes in a vehicle transmission system. A two-phase coupled heat transfer model is established in the study and some fluid-solid coupled heat transfer simulations are performed to investigate the thermal behaviors of wet clutch during sliding by CFD method. Both cooling liquid and grooved solid disks are contained in the heat transfer model and the heat convection due to the cooling liquid in the radial grooves is also considered by fluid-solid coupled transient heat transfer simulations. The temperature distribution and variation of the grooved disk are discussed and analyzed in detail. The results indicate that the temperature distribution on the grooved disk is nonuniform. The temperature within the middle radius area is higher than that in the inner and outer radius area.
2017-10-08
Technical Paper
2017-01-2443
Ziwang Lu, Hongxu Chen, Lijun Wang, Guangyu Tian
Abstract During the engaging process of sleeve and teeth ring in mechanical transmissions, their rotational speed and position differences cause multiple engaging ways and trajectories, and casual impacts between them will delay the engaging process and cause a long power off time for a gear shift. In order to reveal the engaging mechanism of the sleeve and the teeth ring, it is essential to build a high-fidelity model to cover all of their engaging ways and capture their speed changes for an impact. In this work, our contribution is that their impact process is modeled as a precise, continuous and nonlinear damping model, and then a hybrid automaton model is built to connect the system dynamics in different mechanical coupling relationships.
2017-10-08
Journal Article
2017-01-2356
Hyun-Soo Hong, Christopher Engel, Brian Filippini, Sona Slocum, Farrukh Qureshi, Tomoya Higuchi
Abstract Improving vehicle fuel economy is a major consideration for original equipment manufacturers (OEMs) and their technology suppliers worldwide as government legislation increasingly limits carbon dioxide emissions. At the same time that automotive OEMs have been driving toward lower viscosity axle oils to improve fuel economy, OEMs have worked to improved durability over an extended drain interval. These challenges have driven the use of API group III and/or API group IV base oils in most factory fill axle oils. This paper details the development of a novel lower viscosity SAE 75W-85 axle technology based on group II base oil that rivals the performance of a PAO-based axle oil and challenges the conventional wisdom of not using group II base oils in fuel efficient axle oils.
2017-10-08
Journal Article
2017-01-2434
Srinivasan Paulraj, Saravanan Muthiah
Abstract Traditionally driveline ratios are selected based on trial and error method of proto vehicle testing. This consumes lot of time and increases overall vehicle development effort. Over last few decades, simulation-based design approach has been extensively used to alleviate this problem. This paper describes torque converter and final drive ratio (FDR) selection at concept phase for new Automatic Transmission (AT) vehicle development. Most of the critical data required for simulating vehicle performance and fuel economy (FE) targets were not available (e.g. shift map, clutch slip map, pedal map, dynamic torque, coast down, etc.) at an initial stage of the project. Hence, the risk for assuming right inputs and properly selecting FDR/Torque converter was particularly high. Therefore, a validated AVL Cruise simulation model based on an existing AT vehicle was used as a base for new AT vehicle development to mitigate the risk due to non-availability of inputs.
2017-10-08
Journal Article
2017-01-2445
Santosh Deshmane, Onkar P. Gurav, Vipul Sahu
Abstract Today’s automotive industry is facing cutthroat competition, especially in passenger vehicle business. Manufacturers around the globe are developing innovative and new products keeping focus on end customer; thus customer's opinion and perception about the product has become a factor of prime importance. Customer touch points such as gear shift lever, clutch, brakes, steering etc. are thus gaining more and more importance. Car companies are trying to induce more and more luxuries in these touch points so that they impress customer and create a positive opinion about the product. On the other hand manufacturers are also trying to manage profits. Companies thus need to find the best fit solution for improvising customer touch points with optimized costs. The performance of these touch points is driven by subsystems of mechanical components like mechanical linkage.
2017-10-08
Journal Article
2017-01-2436
Santosh Deshmane, Onkar Gangvekar, Samson Rajakumar
Abstract In today’s competitive automobile market, driver comfort is at utmost importance and the bar is being raised continuously. Gear Shifting is a crucial customer touch point. Any issue or inconvenience caused while shifting gear can result into customer dissatisfaction and will impact the brand image. While there are continual efforts being taken by most of the car manufactures, “Double Bump” in gearshift has remained as a pain area and impact severely on the shift feel. This is more prominent in North-South (N-S) transmissions. In this paper ‘Double Bump’ is a focus area and a mathematical / analytical approach is demonstrated by analyzing ‘impacting parameters’ and establishing their co-relation with double bump. Additionally, the results are also verified with a simulation model.
2017-10-08
Journal Article
2017-01-2446
Pengchuan Wang, Nikolaos Katopodes, Yuji Fujii
Abstract Wet clutch packs are the key component for gear shifting in the step-ratio automatic transmission system. The clutch plates are coupled or de-coupled to alter gear ratios based on the driver’s actions and vehicle operating conditions. The frictional interfaces between clutch plates are lubricated with automatic transmission fluid (ATF) for both thermal and friction management. In a 10-speed transmission, there may be as many as 6 clutch packs. Under typical driving conditions, 2 to 3 clutch packs are open, shearing ATF and contributing to energy loss. There is an opportunity to improve fuel economy by reducing the associated viscous drag. An important factor that directly affects clutch drag is the clearance between rotating plates. The axial position of clutch plates changes continuously during operation. It is known in practice that not only the total clearance, but also its distribution between the plates affects the viscous drag.
2017-09-23
Technical Paper
2017-01-1991
Adit Joshi
The automotive industry is heading towards the path of autonomy with the development of autonomous vehicles. An autonomous vehicle consists of two main components. The first is the software which is responsible for the decision-making capabilities of the system. The second is the hardware which encompasses all aspects of the physical vehicle which are responsible for vehicle motion such as the engine, brakes and steering subsystems along with their corresponding controls. This component forms the basis of the autonomous vehicle platform. For SAE Level 4 autonomous vehicles, where an automated driving system is responsible for all the dynamics driving tasks including the fallback driving performance in case of system faults, redundant mechanical systems and controls are required as part of the autonomous vehicle platform since the driver is completely out of the loop with respect to driving.
2017-09-19
Technical Paper
2017-01-2033
Minh-khoa. Lam, Christopher Buterhaugh, Luis Herrera, Bang Tsao
Abstract The amount of electrical power required for future aircraft is increasing significantly. In this paper, a comprehensive model of a drive shaft with multiple degrees of freedom was developed and integrated to detailed engine and electrical network models to study the impact of higher electrical loads. The overall system model is composed of the engine, shafts, gearbox, and the electric network. The Dynamic Dual Spool High Bypass JT9D engine was chosen for this study. The engine was modeled using NASA’s T-MATS (Toolbox for the Modeling and Analysis of Thermodynamic Systems) software. In the electrical side, one generator was connected to the Low Pressure (LP) shaft and the other to the High Pressure (HP) shaft. A modified model of the shafts between the engine and the accessory gearbox was created.
2017-09-19
Technical Paper
2017-01-2124
Violet Leavers
Abstract Within the aviation industry analysis of wear debris particles recovered from magnetic plugs and lubricating fluids is an essential condition monitoring tool. However, in large organisations, high staff turnover in remote work environments often leaves dangerous gaps in on-site support and background knowledge. The current work develops interactive software for wear debris particle classification, root cause diagnosis and serviceability prognostics. During the research several hundred wear debris particle images were collected, analysed and classified by a number of experts. At each stage of the analysis the experts were questioned about the knowledge and experience used to make their diagnoses and prognoses. The end result is an extensive knowledge base representing the combined expertise of a number of highly trained engineers, each with decades of hands-on experience.
2017-09-19
Technical Paper
2017-01-2123
Violet Leavers
Abstract The need to maintain aircraft in remote, harsh environments poses significant challenges. For example, in desert assignments or on-board carrier vessels where frequent rotation of staff with variable levels of skill and experience requires condition monitoring equipment that is not only robust and portable but also user friendly and requiring a minimum of training and skill to set up and use correctly. The mainstays of any on-site aircraft maintenance program are various fluid and particulate condition monitoring tests that convey information about the current mechanical state of the system. In the front line of these is the collection and analysis of wear debris particles retrieved from a component’s lubricating or power transmission fluid or from magnetic plugs. It is standard practice within the specialist laboratory environment to view and image wear debris using a microscope.
2017-09-04
Technical Paper
2017-24-0172
Haijun Chen, Lin Li, Mark Schudeleit, Andreas Lange, Ferit Küçükay, Christian Stamme, Peter Eilts
Abstract In view of the rapidly increasing complexity of conventional as well as hybrid powertrains, a systematic composition platform seeking for the global optimum powertrain is presented in this paper. The platform can be mainly divided into three parts: the synthesis of the transmission, the synthesis of the internal combustion engine (ICE) and the optimization and evaluation of the entire powertrain. In regard to the synthesis of transmission concepts, a systematical and computer-aided tool suitable both for conventional und hybrid transmissions is developed. With this tool, all the potential transmission concepts, which can realize the desired driving modes or ratios, can be synthesized based on the vehicle data and requirements.
2017-09-04
Technical Paper
2017-24-0173
Jean-Charles Dabadie, Antonio Sciarretta, Gregory Font, Fabrice Le Berr
Abstract Due to more and more complex powertrain architectures and the necessity to optimize them on the whole driving conditions, simulation tools are becoming indisputable for car manufacturers and suppliers. Indeed, simulation is at the basis of any algorithm aimed at finding the best compromise between fuel consumption, emissions, drivability, and performance during the conception phase. For hybrid vehicles, the energy management strategy is a key driver to ensure the best fuel consumption and thus has to be optimized carefully as well. In this regard, the coupling of an offline hybrid strategy optimizer (called HOT) based on Pontryagin’s minimum principle (PMP) and an online equivalent-consumption-minimization strategy (ECMS) generator is presented. Additionally, methods to estimate the efficiency maps and other overall characteristics of the main powertrain components (thermal engine, electric motor(s), and battery) from a few design parameters are shown.
2017-09-04
Journal Article
2017-24-0160
Mario Marchetti, Riccardo Russo, Salvatore Strano, Mario Terzo
Abstract The activity described in this paper has been carried out in the framework of a funded project aimed at evaluating the feasibility of a controllable water pump based on an integrated magnetorheological fluid clutch. The advantages consist of an improvement of the overall vehicle performance and efficiency, in the possibility of disengaging the water pump when its action is not required, and in the control of the cooling fluid temperature. So, the design constraints have been defined with reference to the available space, required torque, and electrical power. After an iterative procedure, in which both mechanical design and magnetic field analyses have been considered, the most promising solution has been defined and a first physical prototype has been realized and tested. A preliminary experimental characterization of the developed prototype has been presented.
2017-07-10
Technical Paper
2017-28-1939
Maruti Patil, Penchaliah Ramkumar, Shankar Krishnapillai
Abstract Minimum weight and high-efficiency gearboxes with the maximum service life are the prime necessity of today’s high-performance power transmission systems such as automotive and aerospace. Therefore, the problem to optimize the gearboxes is subjected to a considerable amount of interest. To accomplish these objectives, in this paper, two generalized objective functions for two stage spur-gearbox are formulated; first objective function aims to minimize the volume of gearbox material, while the second aims to maximize the power transmitted by the gearbox. For the optimization purpose, regular mechanical and critical tribological constraints (scuffing and wear) are considered. These objective functions are optimized to obtain a Pareto front for the two-stage gearbox using a specially formulated discrete version of non-dominated sorting genetic algorithm (NSGA-II) code written MATLAB. Two cases are considered, in the first with the regular mechanical constraints.
2017-07-10
Technical Paper
2017-28-1961
Shishir Sirohi, Saurabh Yadav, B. Ashok, V Ramesh Babu, C Kavitha, K Nantha Gopal
Abstract The main objective of the study is to design and analyze casing and supports of a transmission system for an electric vehicle. The system comprises of motors as the power source, constant mesh gear box coupled with limited slip differential as the power transmitting source. The space occupied by the transmission system is a foremost constraint in designing the system. The wear and tear in the system is caused by the gear meshing process and transmission error which lead to failure of the transmission system. This internal excitation also produces a dynamic mesh force, which is transmitted to the casing and mounts through shafts and bearings. In order to overcome such issues in a transmission system, a gear box casing, differential mounts and motor mounts have been designed by the use of CAD-modeling software “SOLIDWORKS”. The designs were imported to FEA software “ANSYS” for carrying out static structural analysis.
2017-07-10
Technical Paper
2017-28-1976
Suresh Kumar Narayana Rao
Abstract The utility of tractors in India has grown and is growing. Other than in agricultural area, it finds use in non-agricultural and construction/ earthmoving applications like loaders, dozers, power source, etc. The tractors that are subjected to heavy duty cycles are mostly with conventional dry type clutches. These types of dry clutch when operated in heavy application generate large amount of heat within shorter period of time on the surface of friction discs. This increase in disc surface temperature weakens the friction material property & bonding element leading to deterioration and decreasing the life of clutch. This curtails the clutch life extensively and is a big challenge to farmers and tractor users. The frequent clutch failures not only increases the operating cost, but also the servicing of clutches in the tractor fitted with heavy attachments leads to a higher downtime and service cost.
2017-07-10
Technical Paper
2017-28-1943
Anil Kumar Jaswal, Rajasekhar Madhurakavi, Pradeep Chandrasekaran
Abstract This paper details about the approach and challenges in converting a conventional vehicle platform designed for diesel/gasoline powertrain into an electrified one. It is not always feasible to accommodate electric powertrain in conventional platforms based on the target requirements. Electrification of conventional vehicles will cut back dependence on fossil fuels, emission of greenhouse gases and emission of pollutants. Fossil fuel are going to be depleted in few decades. Moreover, the emission from traditional vehicle has raised a huge threat to the atmosphere. Auto OEM’s have recognized that electric drive vehicles are critical to the future of the industry. However, some difficulties exist to more noteworthy selection: the view of cost, EV range, access to charging, potential impacts, and absence of open mindfulness about the accessibility and common sense of these vehicles.
2017-06-29
Journal Article
2017-01-9000
Teresa Donateo, Antonio Ficarella
Abstract The design of a hybrid electric powertrain requires a complex optimization procedure because its performance will strongly depend on both the size of the components and the energy management strategy. The problem is particular critical in the aircraft field because of the strong constraints to be fulfilled (in particular in terms of weight and volume). The problem was addressed in the present investigation by linking an in-house simulation code for hybrid electric aircraft with a commercial many-objective optimization software. The design variables include the size of engine and electric motor, the specification of the battery (typology, nominal capacity, bus voltage), the cooling method of the motor and the battery management strategy. Several key performance indexes were suggested by the industrial partner. The four most important indexes were used as fitness functions: electric endurance, fuel consumption, take-off distance and powertrain volume.
2017-06-28
Journal Article
2017-01-9180
Johannes Wurm, Eetu Hurtig, Esa Väisänen, Joonas Mähönen, Christoph Hochenauer
Abstract The presented paper focuses on the computation of heat transfer related to continuously variable transmissions (CVTs). High temperatures are critical for the highly loaded rubber belts and reduce their lifetime significantly. Hence, a sufficient cooling system is inevitable. A numerical tool which is capable of predicting surface heat transfer and maximum temperatures is of high importance for concept design studies. Computational Fluid Dynamics (CFD) is a suitable method to carry out this task. In this work, a time efficient and accurate simulation strategy is developed to model the complexity of a CVT. The validity of the technique used is underlined by field measurements. Tests have been carried out on a snowmobile CVT, where component temperatures, air temperatures in the CVT vicinity and engine data have been monitored. A corresponding CAD model has been created and the boundary conditions were set according to the testing conditions.
2017-06-05
Technical Paper
2017-01-1769
Onkar Gangvekar, Santosh Deshmane
Abstract In today’s automobile market, most OEMs use manual transmission for cars. Gear Shifting is a crucial customer touch point. Any issue or inconvenience caused while shifting gears can result into customer dissatisfaction and will affect the brand image. Synchronizer is a vital subsystem for precise gear shifting mechanism. Based on vehicle application selection of synchronizer for given inertia and speed difference is a key factor which decides overall shift quality of gearbox. For more demanding driver abuse conditions like skip shifting, conventional brass synchronizers have proved inadequate for required speed difference and gear inertia, which eventually results into synchronizer crashing and affects driving performance. To increase synchronizer performance of multi-cone compact brass synchronizer, a ‘Grit blasting process’ has been added. These components tested with an accelerated test plan successfully.
Viewing 1 to 30 of 4774