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Dual mass flywheel (DMF) is an excellent solution to improve the noise, vibration and harshness (NVH) characteristic of any vehicle by isolating the driveline from the engine torsional vibrations. For the same reason, DMFs are widely used in high power-density diesel and gasoline engines. However, the real-world usage conditions pose a lot of challenges to the structural robustness of the DMF. In the present work, a new methodology is developed to evaluate the robustness of a DMF fitted in a compact sports utility vehicle (SUV) with rear-wheel drive architecture.The abuse conditions (mis-gear, sudden braking, etc) in the real-world usage could lead to a sudden engine stall leading to an abnormally high angular deceleration of the driveline components. The higher rate of deceleration coupled with the higher rotational moment of inertia of the systems might end up in introducing a significantly high impact torque on the DMF. Hence, prolonged usage of the vehicle in abuse conditions could lead to a structural failure of the DMF which needs to be assessed during the development stage of a vehicle. In the present work, the authors propose a unique methodology to assess the structural robustness of any DMF. The methodology is a combination of multiple mis-gear shifts and abuse maneuvers creating a high impact torque. The impact torque throughout the testing was measured to establish a correlation with real-world failures. The effectiveness of the methodology is confirmed by comparing the results of the tested DMFs with the long duration high mileage durability DMFs. Moreover, the duration of the methodology is designed to be extremely short that any DMF could be validated within 2 days.In the present work, based on the results of this proposed methodology, the robustness of the DMF could be improved by modifying the internal child parts of the DMF. The paper explains the typical robustness measures needed inside the DMF to avoid real-world structural failures.

© 2018 SAE International. All Rights Reserved. Gear oscillations are one of the most common sources of Noise, Vibration and Harshness (NVH) issues manifested in automotive powertrains. These oscillations are generated mainly due to impacts of the meshing gear teeth over a broad frequency range. To mitigate NVH phenomena, automotive manufacturers traditionally couple linear tuned vibration absorbers to the driveline. Common palliatives used are clutch dampers and dual mass flywheels, which generally suppress vibrations effectively only over narrow frequency bands. Nonlinear Energy Sinks (NESs) are a class of vibration absorbers with essentially nonlinear characteristics that are designed for dissipating vibration energy over broad frequency ranges (due to the employed nonlinearity). The NES does not have a preferential natural frequency; this is rather characterized by the nonlinear stiffness. An NES functions on the principle of transferring energy between the primary system (e.g. driveline) and the absorber in two ways: (i) the NES induces a unidirectional transfer of the vibration energy excess from the primary system to the absorber and (ii) the NES induces a redistribution of the vibration energy excess in the modes of the primary structure, enhancing the energy dissipation capabilities of the primary structure. This paper presents a study on the use of NESs for reducing oscillations on gear pairs operating at low engine operating speeds. Numerical simulations were performed using a gear pair model equipped with an absorber with essentially cubic nonlinear stiffness, attached to the gear wheel. The stiffness and inertia properties of the absorber were varied with the objective of obtaining the parameter combination that induces significant attenuation of the oscillatory motion of the gear wheel. The occurring motion of the system using different sets of parameters is studied and presented.

Clutches are commonly utilised in passenger type and off-road heavy-duty vehicles to disconnect the engine from the driveline and other parasitic loads. In off-road heavy-duty vehicles, along with fuel efficiency start-up functionality at extended ambient conditions, such as low temperature and intake absolute pressure are crucial. Off-road vehicle manufacturers can overcome the parasitic loads in these conditions by oversizing the engine. Caterpillar Inc. as the pioneer in off-road technology has developed a novel clutch design to allow for engine downsizing while vehicle’s performance is not affected. The tribological behaviour of the clutch will be crucial to start engagement promptly and reach the maximum clutch capacity in the shortest possible time and smoothest way in terms of dynamics. A multi-body dynamics model of the clutch system is developed in MSC ADAMS. The flywheel is introducing the same speed and torque as the engine (represents the engine input to the clutch). The hydraulic pressure is applied behind the piston to initiate the engagement. The angular motion of the plates is supported by friction torque between the plates and friction linings. The conjunctions between paper-based linings and steel plates are designed to be dry. Friction (the most significant tribological feature of the linings in torque transmission) is measured in a pin-on-disc tribometer and mapped into the dynamics model in MSC ADAMS. The pin-on-disc tribometer is able to capture the variation of friction coefficient with contact pressure and sliding velocity. The surface topography is obtained experimentally to examine the consistency of surface properties. The normal pressure and tribology of the contacting components determines the engagement time, clutch capacity and dynamic behaviour of the clutch.

The paper presents a mixed theoretical and experimental evaluation of the improvements in fuel economy that follow the introduction of a mechanical Kinetic Energy Recovery System (KERS) on a full size passenger car. This system, made up of a high speed storage flywheel and a Constant Variable Transmission (CVT), has a full regenerative cycle overall efficiency about twice the efficiency of battery-based hybrids. With reference to the baseline configuration having a 4L gasoline engine, adoption of a KERS may reduce the fuel consumption covering the NEDC by 25% without downsizing, and by 33% downsizing the engine to 3.3L.

In order to increase overall energy efficiency of road vehicles, new systems that are able to recover vehicle’s kinetic energy usually lost in dissipating process of frictional braking are being developed. This study was done to look at the effects of integrating Mechanical Flywheel-based Kinetic Energy Recovery System (KERS) into an automotive vehicle. Possible system architectures, due to different connection point of the KERS into the vehicle driveline, were proposed and investigated. Interaction of the system main components (IC engine, vehicle Gearbox, KERS subsystems) was analyzed and explained. In particular, three plots are proposed to introduce a graphical representation that can help the project manager to understand the effect of different parameter values related to the main system components on the overall system behavior during energy transfer from the vehicle to KERS and back.

Ultra-low energy consumption and ultra-low emission vehicle technologies have been developed by combining petroleum-alternative clean energy with a hybrid electric vehicle (HEV) system. Their component technologies cover a wide range of vehicle types, such as passenger cars, delivery trucks, and city buses, adsorbed natural gas (ANG), compressed natural gas (CNG), and dimethyl ether (DME) as fuels, series (S-HEV) and series/parallel (SP-HEV) for hybrid types, and as energy storage systems (ESSs), flywheel batteries (FWBs), capacitors, and lithium-ion (Li-ion) batteries. Evaluation tests confirmed that the energy consumption of the developed vehicles is 1/2 of that of conventional diesel vehicles, and the exhaust emission levels are comparable to Japan's ultra-low emission vehicle (J-ULEV) level. In the analysis of energy consumption improvement factors, it was found that a heavy-duty (HD)-HEV benefits from the effect of regenerative braking to a greater extent than a light-duty (LD)-HEV.

The University of Texas at Austin Center for Electromechanics has designed and integrated a 40,000 rpm, 150 kW, 1.93 kWh flywheel energy storage system into a hybrid electric transit bus as a demonstration of the technology. The flywheel stores energy recovered during braking and returns it to the power train during acceleration, reducing the peak power requirements and size for the prime power unit. Additionally, the system provides a longer life energy storage alternative to the more traditional chemical battery bank. While the flywheel system was demonstrated on a transit bus, similar improvements are possible on other terrestrial or marine mobile applications. This paper presents the results and information learned during several multi-thousand-cycle duration tests, composite flywheel tests, terrain-simulating shaker tests, and on-bus road tests.

Energy storage devices are needed for applications requiring very high power over short periods of time. Such devices have various military (rail guns, electromagnetic launchers, and DEW) and commercial applications, such as hybrid electric vehicles, vehicle starting (SLI), and utility peak shaving. The storage and delivery of high levels of burst power can be achieved with a capacitor, flywheel, or rechargeable battery. In order to reduce the weight and volume of many systems they must contain advanced state-of-the-art electrochemical or electromechanical power sources. There is an opportunity and a need to develop energy storage devices that have improved high power characteristics compared to existing ultra capacitors, flywheels or rechargeable batteries. Electro Energy, Inc. has been engaged in the development of bipolar nickel metal hydride batteries which may fulfill the requirements of some of these applications. This paper describes a module rated at 300 V (255 cells) / 6 Ah. The volume of the module is 23 L and the mass is 56 kg. The module is designed to deliver 50 kW pulses of 10 seconds duration at 50% state of charge. Details of the mechanical design of the module will be presented, along with the results of initial electrical characterization testing. Some discussion of the possibilities for design optimization is also included.

The objective of this paper is to present the development and the use of a numerical model to predict noise radiated from manual gearboxes due to gear rattle using Computer-Aided Engineering (CAE) technologies. This CAE process, as outlined in this paper, includes measured data, computational flexible multibody dynamics, and vibro-acoustic analysis. The measured data is used to identify and reproduce the input excitation which is primarily generated from engine combustion forces. The dynamic interaction of the gearbox components, including flywheel, input/output shafts, contacting gear-pairs, bearings, and flexible housing is modeled using flexible multibody techniques. The acoustic response to the vibration of the gearbox housing is then predicted using vibro-acoustic techniques. These different technologies are augmented together to produce a virtual gearbox that can be used in noise, vibration, and harshness (NVH) performance evaluations. The developed CAE model has a potential of different benefits of using it in the analysis and performance improvements of gearboxes. One major advantage of using such a CAE model is its promising capability in reducing physical prototypes by virtually testing different design modifications. Such reduction in physical prototypes will lead to a substantial reduction in cost and time.

As the need for energy storage increases on future hybrid electric vehicles, the desire for increased performance, energy/power densities, and component life increases proportionally. Flywheel batteries have demonstrated power density and life superiority over conventional chemical batteries; however, fears of unexpected and uncontained failures may prevent their widespread acceptance in the United States marketplace. The University of Texas at Austin Center for Electromechanics (UT-CEM) has designed, built, and tested a full-scale composite flywheel containment system for use in mobile applications. The flywheel containment system that will be described stems from an in-depth investigation into the type of faults that are most likely to occur in mobile applications. In all cases, the worst-case scenario results in a challenge to flywheel integrity; therefore, a comprehensive flywheel containment system is considered the “last line of defense” in protecting personnel and equipment. The containment system described is an energy absorption device used in parallel with a UT-CEM flywheel on the hybrid electric Advanced Technology Transit Bus (ATTB). The most important aspect of the containment device is the free-rotating composite liner intended to absorb the energy of a flywheel failure. The current containment design has been developed over a six-year period during the participation of UT-CEM in the DARPA/DOT Flywheel Containment Program. A comparison between a previous full scale containment test (November 1999) and the current configuration is made, illustrating how “lessons learned” from the previous test are integrated into the latest design. The test was conducted in August 2002 and a detailed description of the mounting configuration, test setup, and data acquisition is presented along with results. Of particular interest to the design team was torque on the aluminum containment housing, axial and hoop stresses in the housing, and acceleration. The test was successful in that the composite debris was contained and all metallic structures remained fully intact. INTRODUCTION In May 1996, Argonne National Laboratory (ANL) was contracted to perform a flywheel battery (FWB) safety assessment for a transit bus [1]. All of the key components of the UT-CEM flywheel battery (energy stored, composite flywheel, speed, magnetic bearings, etc.) had been determined and were used as input into the safety assessment model. ANL recommended a “defense in depth” approach to flywheel safety that included: • engineering to avoid accidental initiation of events • incorporating a safety system for the detection of problems • instituting a mitigation system to minimize the risk of low probability events that could result in a significant energy release In their study, ANL engineers identified the five most likely modes of failure: slow loss of vacuum (a leak), rapid loss of vacuum (a failed hose or pump), failure of magnetic bearings, inadvertent flywheel over speed, and startup without vacuum. In all five of the failure modes described above, the worst-case scenario would result in a challenge to the containment system. After a careful review of the report, UT-CEM made the decision to implement the threephase “defense in depth” approach to prevent the onset of flywheel failure initiators. The first step was to apply good engineering principles in the design phase of the project. Secondly, adequate instrumentation (vacuum, magnetic bearing displacement, and speed sensors) combined with a friendly user interface was designed so that a fault in the system would be indicated and easily recognized. As a third line of defense, a lightweight, rotatable composite liner was designed, tested, and built in the unlikely event of a flywheel burst. J.J. Zierer, J.H. Beno, R.J. Hayes, J.L. Strubhar, R.C. Thompson and T. Pak 2004-01-0005 THIS DOCUMENT IS PROTECTED BY U.S. AND INTERNATIONAL COPYRIGHT It may not be reproduced, stored in a retrieval system, distributed or transmitted, in whole or in part, in any form or by any means. Downloaded from SAE International by Brought to you by the University of Texas Libraries, Wednesday, October 02, 2013 11:06:59 AM

The California Air Resources Board (ARB) developed a Medium Heavy-Duty Truck (MHDT) schedule by selecting and joining microtrips from real-world MHDT. The MHDT consisted of three modes; namely, a Lower Speed Transient, aHigher Speed Transient, and a Cruise mode. The maximum speeds of these modes were 28.9, 58.2 and 66.0 mph, respectively. Each mode represented statistically selected truck behavior patterns in California. The MHDT is intended to be applied to emissions characterization of trucks (14,001 to 33,0001b gross vehicle weight) exercised on a chassis dynamometer. This paper presents the creation of the MHDT and an examination of repeatability of emissions data from MHDT driven through this schedule. Two trucks were procured to acquire data using the MHDT schedule. The first, a GMC truck with an 8.2-liter Isuzu engine and a standard transmission, was tested at laden weight (90% GVW, 17,5501b) and at unladen weight (50% GVW, 9,7501b). The second, a Freightliner with a 7.2-liter Caterpillar engine and an automatic transmission, was tested only at 13,000lb (50% GVW). The test runs were performed using the West Virginia University (WVU) medium-duty chassis dynamometer, located in Riverside, CA. Vehicle inertia was mimicked using a flywheel set, and tire and wind drag were mimicked using an eddy current power absorber. The truck exhaust was ducted to a full-scale dilution tunnel, with HEPA filtered dilution air, and a flow rate of approximately 1,500scfm. Particulate matter (PM) mass was found gravimetrically, using filtration, while carbon dioxide (CO 2 ), carbon monoxide (CO), oxides of nitrogen (NO x ) and hydrocarbons (HC) were measured using research grade analyzers. Data were computed in units of g/cycle, g/mile, g/ahp-hr, g/gallon and g/minute, and were examined most carefully in units of g/mile. Preliminary runs showed that the GMC truck did deviate from the target trace when tested at laden weight, and the completed distance for the MHDT Lower Speed Transient mode varied from 0.906 to 0.954 miles. Laden data from the GMC truck demonstrated that emissions were repeatable for all three modes of the MHDT schedule. Averaged GMC truck results for all laden runs of the Lower Speed Transient mode were 8.99g/mile NO x and 0.26g/mile PM results for the Higher Speed Transient mode were 6.50g/mile NO x and 0.20g/mile PM and for the Cruise mode were 4.73g/mile NO x and 0.09g/mile PM. Unladen data from the GMC truck also showed acceptable repeatability, with emissions of NO x that were about 87% of the laden values. The Freightliner, with an automatic transmission, produced 16.39g/mile NO x and 0.33g/mile PM on the Lower Speed Transient mode, 12.59g/mile NOX and 0.25g/mile PM on the Higher Speed Transient mode, 7.93g/mile NO x and 0.14g/mile PM on the Cruise mode and 7.57g/mile NO x and 0.19g/mile PM on the UDDS (Test D). when three runs of thee same mode were run back-to-back, the standard deviation of NO x values for six sequences of runs were under 4% of the average for all three modes on both the manual transmission truck at laden test weight and the automatic transmission truck at unladen weight. CO 2 variation was under 4% as well, except in one instance. In two of the six sequences PM variability exceeded 10%. The researchers concluded that the MHDT was suitable for characterizing the emissions from trucks in future inventory research. Data also showed that emissions from a mode were unaffected by whichever mode was run previously.

The objective of this paper is to show the design and definition of a clean electric bus prototype for the urban transportation in the city of Zaragoza (Spain). For this aim we have used, as general initial data, the bodywork of the HABIT City Class from the bus maker company HISPANO and a double energy source (fuel cell as a primary energy source and flywheels as auxiliary one) which feeds two permanent magnet synchronous electric motors inserted and directly coupled with the rear wheels (hub electric motors). We have selected as well all necessary components that should be included in this prototype and we have integrated therp at the prototype bodywork.

This paper describes the DC bus regulation control algorithm for the NASA flywheel energy storage system during charge, charge reduction and discharge modes of operation. The algorithm was experimentally verified with results given in a previous paper. This paper presents the necessary models for simulation with detailed block diagrams of the controller algorithm. It is shown that the flywheel system and the controller can be modeled in three levels of detail depending on the type of analysis required. The three models are explained and then compared using simulation results.

Road vehicles can expend a significant amount of energy in undesirable vertical motions that are induced by road bumps, and much of that is dissipated in conventional shock absorbers as they dampen the vertical motions. Presented in this paper are some of the results of a study aimed at determining the effectiveness of efficiently transforming that energy into electrical power by using optimally designed regenerative electromagnetic shock absorbers. In turn, the electrical power can be used to recharge batteries or other efficient energy storage devices (e.g., flywheels) rather than be dissipated. The results of the study are encouraging - they suggest that a significant amount of the vertical motion energy can be recovered and stored.

Manufacturing readiness of composite rotors and certification of flywheels depend in part on the maturity of nondestructive evaluation (NDE) technology for process optimization and quality assurance, respectively. Capabilities and limitations of x-ray-computed tomography and radiography, as well as advanced ultrasonics were established on NDE ring and rotor standards with EDM notches and drilled holes. Also, intentionally seeded delamination, tow break, and insert of bagging material were introduced in hydroburst-rings to study the NDE detection capabilities of such anomalies and their effect on the damage tolerance and safe life margins of subscale rings and rotors. Examples of possible occurring flaws or anomalies in composite rings as detected by NDE and validated by destructive metallography are shown. The general NDE approach to ensure quality of composite rotors and to help in the certification of flywheels is briefly outlined.

Electric vehicles today clearly represent the only solution fulfilling the zero emission vehicles (ZEV) standard. However, they still are not an equivalent alternative to the gasoline driven cars due to the well known problems of today's batteries. The concept of a parallel hybrid drive line can be an optimal combination of both principles of propulsion in that the gasoline engine guarantees for a wide range operation, while the electric propulsion can be used within the restricted zero emission zones [19]. The parallel hybrid drive train described here has been realized at the Swiss Federal Institute of Technology (ETH), Zurich, Switzerland. The drive line consists of a spark ignited engine, an electric asynchronous machine, a flywheel, and a wide range continuously variable transmission. An overall control system has been developed for the drive train. This drive line has been integrated in a multi purpose van for real road testing. This paper describes the experimental results from various component testing, from a dynamic test bench and from a chassis dynamometer test bench. Fuel efficiency improvement of higher than 40% are achieved in the urban driving cycles.