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Technical Paper
2014-04-01
Jeremie Dernotte, John Dec, Chunsheng Ji
This article presents an investigation of the sources combustion-generated noise and its measurement in HCCI engines. Two cylinder-pressure derived parameters, the Combustion Noise Level (CNL) and the Ringing Intensity (RI), that are commonly used to establish limits of acceptable operation are compared along with spectral analyses of the pressure traces. This study focuses on explaining the differences between these two parameters and on investigating the sensitivity of the CNL to the ringing/knock phenomenon, to which the human ear is quite sensitive. Then, the effects of independently varying engine operating conditions such as fueling rate, boost pressure, and speed on both the CNL and RI are studied. Results show that the CNL is not significantly affected by the high-frequency components related to the ringing/knock phenomenon. In contrast, CNL is found to be sensitive to increasing energy in the 0.4 to 2.0 kHz frequency range generated by the combustion-induced uniform pressure rise.
Technical Paper
2014-04-01
Hiroki Yamaura, Masao Ishihama, Kazuhide Togai
Engine torque profile shaping strategies have been proposed to reduce noise & vibration for passenger cars. However, it has not been sufficiently studied that feasible torque profile for vibration suppression is dependent on engine speed and target torque shape. On the other hand, combustion pressure profile shaping strategies have been proposed to reduce noise. However, there is almost no research of the quantitative evaluation of contribution of combustion pressure profile. First, the torque profile shaping was studied. Pre-compensated torque and 2-step torque were selected as typical target torque profiles. An effectiveness of vibration suppression by two torque profiles was evaluated by both drivetrain vibration model and engine torque profile model which have been established well. As a result of studying the torque profile shaping, timing of torque rise by the 2-step torque generation is delayed or advanced. Torque profile by the pre-compensation is deformed in steep change part.
Technical Paper
2014-04-01
Joe Serrano, Geoff Routledge, Norman Lo, Mark Shost, Vijay Srinivasan, Biswa Ghosh
Cylinder deactivation is a technology seeing increased automotive deployment in light of more demanding fuel economy and emissions requirements. Examples of current production systems include GM's Active Fuel Management and Chrysler's Multi-Displacement System, both of which provide one fixed level of deactivation. Dynamic Skip Fire (DSF), in which the number of fired cylinders is continuously varied to match the torque demand, offers significantly increased fuel savings over a wider operating range than the current production systems. One of the biggest challenges in implementing cylinder deactivation is developing strategies to provide acceptable Noise, Vibration and Harshness (NVH); this paper discusses those challenges and the methodologies developed. This work covers theoretical root causes; proposed metrics to quantify the NVH level; algorithmic and physical mitigation methods; and both subjective and objective evaluation results.
Technical Paper
2014-04-01
Kenji Torii
A technique was created to separate the contributions of combustion noise and mechanical noise to engine noise in the time domain in order to achieve efficient measures for enhancing the sound quality of combustion noise. There is an existing technique based on 1/3 octave band analysis that is known as a method for separating the contributions to engine radiation noise, but this technique cannot provide time-domain data. Therefore, the author has proposed a technique that separates engine radiation noise into combustion noise and mechanical noise in the time domain by finding the combustion noise for each cylinder and calculating its structural response function by considering its real and imaginary components. Results of analysis of actual engine radiation noise with this technique confirmed that combustion noise, which is characterized by strong pulsation, and irregular mechanical noise can be separated in the time domain with good precision. Moreover, the structural response function, combustion noise, and mechanical noise characteristics showed a valid changing trend in response to changes in cylinder pressure and structural specifications.
Technical Paper
2014-04-01
Sung Young Shin, Sang Dong Lee, Bong Chul Go
Abstract In terms of the responsive quality of cars, reducing the vibration of car seats is very important, as this vibration is transmitted directly to the driver. Here, a sensitivity analysis method was used to reasonably reduce the vibration of car seats at minimal cost. A laboratory test was conducted under two excitation conditions: first, vibration in idle state; second, random vibration not exceeding 100 Hz. To determine the reliability of the laboratory test, the actual vibration in idle state was simulated in a multi-axial simulation table for the idle excitation environment of cars that are sensitive to even the smallest changes in the environment. The frequencies of interest were selected by adding the sums of frequency response functions measured at the 24 nodal points of interest under the two excitation conditions. Sensitivity factors were derived at the 24 nodal points of interest and a design modification plan with relatively large sensitivity factors was suggested to reinforce the overall rigidity of the part modules containing the points of interest.
Technical Paper
2014-04-01
Se Jin Park, Seung Nam Min, Murali Subramaniyam, Heeran Lee, Dong Gyun Kim, Cheol Pyo Hong
Abstract Vibration is both a source of discomfort and a possible risk to human health. There have been numerous studies and knowledge exists regarding the vibrational behavior of vehicle seats on adult human occupants. Children are more and more becoming regular passengers in the vehicle. However, very little knowledge available regarding the vibrational behavior of child safety seats for children. Therefore, the objective of this study was to measure the vibrations in three different baby car seats and to compare these to the vibrations at the interface between the driver and the automobile seat. The test was performed on the National road at the average speed of 70 km/h and acceleration levels were recorded for about 350 Sec (5.83 min). One male driver considered as an adult occupant and a dummy having a mass of 9 kg was representing one year old baby. Four accelerometers were used to measure the vibration. All measured accelerations were relative to the vertical direction. Vibration Analysis Toolset (VATS) was used for time domain analysis.
Technical Paper
2014-04-01
Prasad Kumbhar, Ning Li, Peijun Xu, James Yang
In vehicle driving environment, the driver is subjected to the vibrations in horizontal, vertical, and fore-aft directions. The human body is very much sensitive to whole body vibration and this vibration transmission to the body depends upon various factors including road irregularities, vehicle suspension, vehicle dynamics, tires, seat design and the human body's properties. The seat design plays a vital role in the vibration isolation as it is directly in contact with human body. Vibration isolation properties of a seat depend upon its dynamic parameters which include spring stiffness and damping of seat suspension and cushion. In this paper, an optimization-based method is used to determine the optimal seat dynamic parameters for seat suspension, and cushion based on minimizing occupant's body fatigue (occupant body absorbed power). A 14-degree of freedom (DOF) multibody biodynamic human model in 2D is selected from literature to assess three types of seat arrangements. The human model has total mass of 71.32 kg with 5 body segments.
Collection
2014-04-01
This technical paper collection covers intake/exhaust/powertrain and chassis noise and vibration.
Collection
2014-04-01
This technical paper collection sets out to reflect the recent advances on the research, development and practices of Powertrain NVH treatment. The coverage includes: engine, engine subsystem and components noise and vibration; powertrain systems noise measurement and instrumentation; powertrain systems noise analysis.
Technical Paper
2014-04-01
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. The result of analysis shows that the dynamic torsional fluctuations of the drive shaft and rear drive module (RDM) vibration are the major contributors for the high levels of vibration and noise.
Technical Paper
2014-04-01
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. The torque control software calibration and the driveline elements were developed in order to reduce the noise and vibration critical frequency ranges.
WIP Standard
2014-03-25
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.
WIP Standard
2014-03-25
Various SAE vehicle sound level measurement procedures require use of a sound level meter which meets the Type 1 or Type 2 requirements of ANSI S1.4-1983 (see 2.1.1.1), or an alternative system which can be proved to provide equivalent test data. The purpose of this SAE Recommended Practice is to provide a procedure for determining if a sound data acquisition system (SDAS) has electro-acoustical performance equivalent to such a meter. By assuring equivalent performance of the test instrumentation, the equivalence of test data is assured. Two general configurations of sound data acquisition systems will be encompassed (see Figure 1). The first configuration consists of instrument sections which perform as a sound level meter. The second configuration is a system which records data for later processing. The intent of this document is to establish guidelines which permit the test engineer to insure equivalence of sound data acquisition systems to a sound level meter. It requires that the test engineer have a working knowledge of the characteristics of the sound data being measured.
Article
2014-03-24
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.
Technical Paper
2014-03-24
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. Forces predicted from MBD simulation at each engine mounts are applied to full vehicle FE model.
Article
2014-03-12
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.
Article
2014-03-12
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.
Article
2014-03-11
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.
Article
2014-03-10
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.
Article
2014-03-10
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.
Article
2014-03-10
Jesse Garant & Associates (JG&A) Metrology Center offers industrial CT scanning focused on 3-D internal part inspection services using industrial computed tomography equipment.
Article
2014-03-10
CD-adpaco fills the design testing void with multidisciplinary design exploration (MDX), a methodology for automatically testing designs from early in the concept stage.
Article
2014-03-10
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.
WIP Standard
2014-03-06
To provide a method that accounts for the attenuation due to line-of-sight blockage of aircraft noise by terrain features.
WIP Standard
2014-03-06
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."
Magazine
2014-03-04
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.
Article
2014-03-03
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.
Magazine
2014-03-01
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.
Article
2014-02-26
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.
Article
2014-02-17
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.
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