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Viewing 271 to 300 of 8700
2014-04-01
Technical Paper
2014-01-1700
Xiaobing Liu, Paul Nahra, Anna Strehlau
Abstract Engine stop/start systems are one technology being developed to meet ever tightening fuel economy regulations. Several production vehicles in the market have adopted stop/start systems with 12 volt batteries and enhanced starters. During engine autostart events (restart after autostop), the engine/vehicle vibration may be objectionable to customers. In this paper, the impact of extended range retarded intake cam phasing on first cycle combustion and vehicle vibration during engine autostart is provided. The engine intake cam phasers of a production vehicle were modified so the effective compression during autostart could be set as low as 3.5. Achieving these autostart conditions while maintaining typical cam timing positions under cold start conditions is achievable with an innovative dual park phaser. NVH measurements and engine speed traces indicate that this approach reduced vibration during engine autostart by a measurable amount.
2014-04-01
Technical Paper
2014-01-1708
Xiaoxun Chen, Yu Zhang, Yunqing Zhang, Ming Jiang
Abstract In the present study, the research of the exhaust system is performed in three steps. In the first step, the average driving degree of freedom displacement (ADDOFD) is calculated by the free modal analysis of the exhaust system. It is easy to find the reasonable location of the hanger according to the value of the ADDOFD, since it represents the relative size of some DOF's response displacement at excitation state. The second of which is to analyse the vibration isolation performance of the exhaust system based on the first step. The dynamic analysis of the exhaust system together with the powertrain is studied, by which way the unit sinusoidal excitation is applied at the powertrain's mass centre, so that the response force at the hanger can be obtained. Finally, the relationship between the constrained model of the exhaust system and the stiffness of the hanger is investigated, which is significant in engineering.
2014-04-01
Technical Paper
2014-01-1874
Tae-il Yoo, Hanhee Park, Gubae Kang, Seongyeop Lim
Abstract Development of eco-friendly vehicles have risen in importance due to fossil fuel depletion and the strengthened globalized emission control regulatory requirements. A lot of automotive companies have already developed and launched various types of eco-friendly vehicles which include hybrid vehicles (HEVs) or electric vehicles (EVs) to reduce fuel consumption. To maximize fuel economy Hyundai-Kia Motor Company has introduced eco-friendly vehicles which have downsized or eliminated vibration damping components such as a torque converter. Comparing with Internal Combustion Engine(ICE) powered vehicles, one issue of the electric motor propulsion system with minimized vibration damping components is NVH (Noise, Vibration and Harshness). The NVH problem is caused by output torque fluctuation of the motor system, resulting in the degradation of ride comfort and drivability.
2014-04-01
Technical Paper
2014-01-1758
Zamir Zulkefli, Maurice Adams
Abstract Gears are used in numerous applications where mechanical power needs to be transmitted as in the powertrain of cars, buses and other vehicles. These gears can potentially be a significant source of high-frequency vibration and radiated noise in a vehicle, which can be both harmful and objectionable to any listeners in the vicinity. A proposed approach to addressing the gear mesh-frequency vibrations is to utilize the low pass filtering effect of a hydrostatic bearing in a gear mesh-frequency noise mitigation system. This paper describes an experimental investigation of the low pass filtering effect of a hydrostatic bearing using an experimental setup involving a widely available materials testing machine. By using the materials testing machine, appropriately sized hydrostatic bearing and externally pressurized fluid supply system, empirical data was collected that allowed the frequency response of the hydrostatic bearing to be determined.
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
2014-01-1756
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
2014-01-1974
Gaurav Gupta, Rituraj Gautam, Chetan Prakash Jain
Abstract Interior sound quality is one of the significant factors contributing to the comfort level of the occupants of a passenger car. One of the major reasons for the deterioration of interior sound quality is the booming noise. Booming noise is a low frequency (20Hz∼300Hz) structure borne noise which occurs mainly due to the powertrain excitations or road excitations. Several methods have been developed over time to identify and troubleshoot the causes of booming noise [1]. In this paper an attempt has been made to understand the booming noise by analyzing structural (panels) and acoustic (cavity) modes. Both the structural modes and the acoustic modes of the vehicle cabin were measured experimentally on a B-segment hatchback vehicle using a novel approach and the coupled modes were identified.
2014-04-01
Journal Article
2014-01-1976
Shuming Chen, Dengfeng Wang
In this paper, the relationship was investigated between objective psychoacoustic parameters, A-weighted sound pressure level (SPL) and the results of the subjective evaluation by using grey relational analysis (GRA). The sounds were recorded with eight different passenger cars at four different running conditions. The sound quality indices were calculated, including loudness, sharpness, roughness, fluctuation, and A-weighted SPL. Subjective evaluation was performed by thirty subjects using rating scale method. GRA was compared with traditional correlation analysis, and the comparison shows that some hidden information which could not be found in the traditional correlation analysis was revealed. In order to know the further relationship between fluctuation and subjective evaluation, another subjective evaluation was performed by the same 30 subjects. The result demonstrates that the relationship revealed from GRA is correct.
2014-04-01
Technical Paper
2014-01-1975
Manchi Venkateswara Rao, Jos Frank, Prasath Raghavendran
Abstract The customer demand for all wheel drive (AWD) vehicles is increasing over the period of time which also requires NVH performance on par with front wheel drive vehicles. AWD vehicles are equipped with power transfer unit, propeller shaft and independent rear differential assembly to achieve their functional requirement. The additional drive train components in AWD vehicles may amplify torsional fluctuations in the drive line. Hence achieving the NVH performance of AWD vehicles on par with FWD vehicles without any major change in the existing design is a major challenge. In this work, an AWD vehicle with severe body vibration and booming noise is studied. The operational measurements are taken throughout the drive train on all sub-systems from engine to the rear part of the body in the problematic operating condition. An operational deflection shape analysis is conducted to visualize the vibration behavior of the drive train.
2014-04-01
Journal Article
2014-01-1938
Pragadish Nandakumar
The fuel prices are increasing every day and so are the pollution caused by vehicles using fossil fuels. Moreover, in a car with an internal combustion engine, we get on average 25% efficiency, the other 75% is wasted, mostly through friction and heat. One important loss is the dissipation of vibration energy by shock absorbers in the vehicle suspension under the excitation of road irregularity and vehicle acceleration or deceleration. In this paper we design, manufacture and test a regenerative coil-over strut that is compact, simple in design and more economical. Since our strut is a modification of an existing strut design, it would be much more feasible to implement. We tested our prototype strut using a TATA Indica car under city road conditions. The damping characteristics and output voltage of the strut were recorded and compared with a normal coil over strut. Based on the test data, it was found that the strut was able to recover about 8-10 watts of electricity at 20kmph.
2014-04-01
Journal Article
2014-01-1981
Devadatta Mukutmoni, Robert Powell, L.A.Raghu Mutnuri
Flow generated acoustic sources are of significant import for automotive applications since perception of noise is a critical customer satisfaction issue. High temperature acoustic sources known as thermo-acoustics such as those occurring inside an exhaust system of a vehicle, an important subset of acoustic sources, is the subject of the investigation. In this article, we study a Rijke tube configuration that consists of a vertical and hollow cylindrical tube open at both ends where sound is generated by buoyancy driven flow as a result of a heated wire gauze placed in the bottom half of the tube. This configuration captures the essence of the thermo-acoustic phenomena and was investigated both numerically and experimentally and good agreement was observed between the two.
2014-03-25
WIP Standard
J1477
This SAE Recommended Practice establishes the test procedure, environment, instrumentation, and data analyses for comparing interior sound level of passenger cars, multipurpose vehicles, and light trucks having gross vehicle weight rating (GVWR) of 4540 kg (10 000 lb) or less. The test procedure is characterized by having fixed initial conditions (specified initial vehicle speed and gear selection at the starting point on the test site) to obtain vehicle interior sound measurement during road load operation over various road surfaces at specified constant speeds. The measurement data so derived is useful for vehicle engineering development and analysis.
2014-03-24
Article
Massachusetts will be the home, and MIT the beneficiary, of a new FAA-designated unmanned aircraft test site just an hour and a half from campus. MIT classes and researchers developing unmanned aerial vehicles and their associated systems will be able to take advantage of the facility located at Joint Base Cape Cod, according to MIT Professor Jonathan How of the Department of Aeronautics and Astronautics.
2014-03-24
Technical Paper
2014-01-2015
Ulhas Mohite, Prashant Bhavsar
Abstract In this paper the approach to predict vibrations in motorcycles is presented. It can be divided mainly in two parts: prediction of engine forces using multi body dynamics (MBD) simulation and prediction of vibration response using FEA. Dynamic forces predicted at each engine mount through MBD simulation are used as input to FE analysis for vibration prediction. Single cylinder SI engine having primary balancer shaft is considered to develop this methodology. Flexibilities of important parts are considered for MBD simulation. Crankshaft ball bearing which is used in almost all two wheeler engine is modeled with 6×6 stiffness matrix. It provides coupling between radial, axial and tilting deflections of bearing and it also allows moment transfer from crankshaft to casing. This helps to predict realistic forces at each bearing and engine mounts. Distribution of primary and secondary forces at crank bearings and at different engine mounts is studied.
2014-03-12
Article
DGE Inc.'s HMIts, which simulates a user’s speech and touch and then validates the response of the infotainment system, enables OEMs and Tier suppliers to perform repetitive testing on any HMI/infotainment system in a controlled environment, ensuring accurate results and eliminating the need for time-consuming and labor-intensive manual test plans.
2014-03-12
Article
dSPACE’s latest solution for electric motor testing combines SCALEXIO hardware-in-the-loop (HIL) simulation technology with an DS2655 FPGA base module and a scalable electronic load to enable users to test electric motor control systems in a more realistic environment by emulating the real motor and generator currents.
2014-03-11
Article
The Miniscan IRXpert analyzer from AMETEK Petrolab Co. is a portable multi-fuel analyzer for gasoline, diesel, and biodiesel blends incorporating mid-IR and near-IR spectroscopy to achieve accuracy of fuel properties. It will be displayed a the SAE 2014 World Congress in Detroit April 8-10.
2014-03-10
Article
Billing itself as the "first-ever open-source race team," Perrinn myTeam is inviting students, professional engineers, and others to contribute and share data for development of a possible sports car entry at Le Mans in 2015.
2014-03-10
Article
Engineers at NASCAR's Research & Development Center in Concord, NC, recently performed three separate window net and window net mounting tests and used them to design an improved window net mounting system for the 2013 season.
2014-03-10
Article
Jesse Garant & Associates (JG&A) Metrology Center offers industrial CT scanning focused on 3-D internal part inspection services using industrial computed tomography equipment.
2014-03-10
Article
CD-adpaco fills the design testing void with multidisciplinary design exploration (MDX), a methodology for automatically testing designs from early in the concept stage.
2014-03-10
Article
NanoFocus’ μsurf cylinder tool, which will be displayed at the SAE 2014 World Congress April 8-10 in Detroit, provides a nondestructive technique for high-resolution 3-D measurements of the inside of cylinder bores and liners.
2014-03-06
WIP Standard
AIR6297
To provide a method for modeling the noise directivity behind start-of-takeoff roll based on empirical data from modern jet aircraft. This method would replace the method described in Section 3.3.1 of SAE-AIR-1845A "Procedure for the Calculation of Airplane Noise in the Vicinity of Airports."
2014-03-06
WIP Standard
AIR6501
To provide a method that accounts for the attenuation due to line-of-sight blockage of aircraft noise by terrain features.
2014-03-04
Magazine
What's New at ConExpo/IFPE More new products and technologies that companies plan to showcase at this year's ConExpo-Con/Agg, which is co-located with the IFPE fluid-power event in Las Vegas from March 4-8, are previewed. Gearshift actuator dynamics in a dual clutch transmission The emergence of tougher environmental and fuel efficient legislations have triggered exploration and advance toward new and better vehicle transmission technologies. Software makes solid impact Programs are helping hydraulic systems do more while reducing operator workloads. Damping out booming noise NVH improvement techniques are gaining traction with the goal to improve the quality perception of off-highway equipment performance and operator comfort.
2014-03-03
Article
One of the subject areas garnering the most attention at the SAE 2014 World Congress is aerodynamics because of its effect on vehicle efficiency through drag reduction and the potential for real-world fuel economy gains.
2014-03-01
Magazine
The future for electric and hybrid vehicles in India Technical and political challenges alike have held back the electric and hybrid market, but there are signs of hope. Flex-fuel snowmobile challenge results in improved efficiency and lower emissions Noise and exhaust emissions of recreational snowmobiles have come under increased scrutiny by the U.S. federal government. Students from Kettering University take on the design challenges of meeting or exceeding such regulations. Actuator dynamics in a dual clutch transmission The emergence of tougher environmental and fuel efficient legislations have triggered exploration and advance toward new and better vehicle transmission technologies.
2014-02-26
Article
Technical sessions focused on interiors at the SAE 2014 World Congress span the designated technology areas, including electronics, materials, and safety/testing. One example in the electronics area, to take place April 8 at 9:30 a.m., covers multi-media systems. As part of the discussion, Takata researchers will present new touchscreen concepts such as a smart display surface that could benefit steering-wheel design.
2014-02-17
Article
The four-year, $15 million development program with UW-Madison and Wayne State University aims to achieve diesel levels of efficiency and torque, with lower emissions and cost—in an advanced gasoline-fueled engine.
2014-02-12
Article
A new approach is presented for wind tunnel calibrations based on a limited number of dynamic pressure measurements and a predictive technique using Neural Network (NN).
Viewing 271 to 300 of 8700

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