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Journal Article

Direct Aeroacoustic Simulation of Flow Impingement Noise in an Exhaust Opening

2011-05-17
2011-01-1517
Unusual noises during vehicle acceleration often reflect poorly on customer perception of product quality and must be removed in the product development process. Flow simulation can be a valuable tool in identifying root causes of exhaust noises created due to tailpipe openings surrounded by fascia structure. This paper describes a case study where an unsteady Computational Fluid Dynamics (CFD) simulation of the combined flow and acoustic radiation from an exhaust opening through fascia components provided valuable insight into the cause of an annoying flow noise. Simulation results from a coupled thermal/acoustic analysis of detailed tailpipe opening geometry were first validated with off-axis microphone spectra under wide open throttle acceleration. After studying the visualizations of unsteady flow velocity and pressure from the CFD, a problem that had proved difficult to solve by traditional “cut and try” methods was corrected rapidly.
Technical Paper

Design of Rotorcraft Gearbox Foundation for Reduced Vibration and Increased Crashworthiness Characteristics

2011-05-17
2011-01-1704
Vehicle design is a complex process requiring interactions and exchange of information among multiple disciplines such as fatigue, strength, noise, safety, etc. Simulation models are employed for assessing and potentially improving a vehicle's performance in individual technical areas. Challenges arise when designing a vehicle for improving mutually competing objectives, satisfying constraints from multiple engineering disciplines, and determining a single set of values for the vehicle's characteristics. It is of interest to engage simulation models from the various engineering disciplines in an organized and coordinated manner for determining a design configuration that provides the best possible performance in all disciplines. The multi-discipline design process becomes streamlined when the simulation methods integrate well with finite element or computer aided design models.
Journal Article

Forward Collision Mitigation Systems: A Safety Benefits Analysis for Commercial Vehicles via Hardware-in- the-loop Simulation

2011-09-13
2011-01-2259
Forward collision mitigation systems (FCMS) are becoming standard in passenger car vehicles with the current trend of safety technologies development. Currently, safety systems are on the road towards widespread acceptance in the commercial vehicle industry. Whereas the full Electronic Stability Control (ESC) system attempts to sense the states of the vehicle to assist the driver to maintain directional control of the vehicle, current FCMS attempts to sense the environment around the front of the vehicle and either warns the driver to react or intervenes by slowing down the vehicle autonomously. Some of the latest developments in FCMS for commercial vehicles will be discussed, together with an outlook of future systems. This study will also examine some of the common scenarios that forward collision mitigation systems can be beneficial in, especially for commercial vehicles. The scenarios will be investigated using Hardware-in-loop-simulation, and the results discussed.
Technical Paper

Multi Layered Maps for Enhanced Environmental Perception

2011-09-13
2011-01-2244
Traditionally, an in-vehicle map consists of only one type of data, tailored for a single user function. For example, the navigation maps contain spatial information about the roads. On the other hand, a map built for adaptive cruise control use consists of the detected vehicles and their properties. In autonomous vehicle research, the maps are often built up as an occupancy grid where areas are classified as passable or impassable. Using these kinds of maps separately, however, is not enough to support the traffic safety enhancing and advanced driver assistance systems of today and tomorrow. Instead of using separate systems to handle individual safety or planning tasks, information could be stored in one shared map containing several correlated layers of information. Map information can be collected by any number of different sensor devices, and fusion algorithms can be used to enhance the quality of the information.
Journal Article

Field Demonstration of Heavy Vehicle Camera/Video Imaging Systems

2011-09-13
2011-01-2245
To help drivers monitor the road and to reduce blind spots, Camera/Video Imaging Systems (C/VISs) display live video from cameras mounted on the truck's exterior to drivers using displays inside the truck cabin. This study investigated drivers' performance with C/VISs in a real-world trucking operation. Twelve commercial drivers' performance with and without a C/VIS was continuously recorded while they each drove for four months. Half of the drivers used a commercially available C/VIS that had a side-view camera on each fender. The other drivers used an advanced C/VIS (A-C/VIS) that had side-view cameras, a rear-view camera, and night-vision capabilities. This paper presents the study's final results and expands on the preliminary results that were previously reported. Detailed analyses of drivers' involvement in Safety-Critical Events (SCEs), their lane change performance, and their opinions of the C/VISs are presented.
Technical Paper

Experimental Study of Energy Balance for Air-Cooled DI Diesel Engines Operating in Hot Climates

2009-06-15
2009-01-1974
The effects of various loads and climatic conditions, as well as the engine’s characteristics on the thermal balance and a modification of the engine air-cooling system are presented. Thermal balance tests were conducted for engine thermal efficiency, heat loss through the exhaust gases, heat loss to the cooling air and unaccounted losses (i.e. heat lost by lubricating oil, radiation). While performance tests were in respect to the brake power, specific consumption was tested at different loads, and at ambient air temperature. The analysis of the statistics, and the experimental measurements, reveal interesting aspects of the engine heat transfers. A modification of the cooling system by adding fins at the engine inlet is carried out in order to reduce the thermal charge on the fourth cylinder.
Technical Paper

A High Performance Passive Muffler Valve

2009-05-19
2009-01-2039
A new passive muffler valve has been developed that offers the advantages of both the current passive and active valves without their major drawbacks. Like current passive valves this new valve provides high restriction at low to medium engine speeds for improved noise control. But with a near over-center spring action and unique flap shape, this high performance valve has minimal pressure drop at high engine speeds, closer to the active valve pressure drop performance. The in-line design of the valve makes it ideal for low restriction OE mufflers, resonators, and aftermarket performance mufflers. The new valve design is uncomplicated, with few components and has been tested extensively for durability utilizing both bench and vehicle level testing.
Technical Paper

Analysis of Road Traffic Accidents on NH 45 (Kanchipuram District)

2009-12-13
2009-28-0056
With the support and cooperation of the Kanchipuram district police and Tamil Nadu police, researchers conducted detailed investigations of accidents occurring on the National Highway 45 over a 60 km stretch. The primary objective was to collect and analyze India-based traffic crash data to begin to create a sound basis for decision making for improving safety on India's roadways. A secondary objective was to establish a standardized methodology using economical tools for collecting and analyzing crash data, specific to Indian roads. For the 45 day study period, an accident intimation network was established between researchers and all police stations/highway patrols in the study area. On occurrence of an accident, police called a 24-hour contact number and researchers responded to the scene. On site, researchers used standardized reporting forms, methodologies, and equipment to perform accident scene examinations, accident vehicle examination, and AIS injury coding.
Technical Paper

Design of the Occupant Protection System for Critical Side Impact requirements

2009-12-13
2009-28-0055
This paper describes the critical side impact requirements of overall global side regulations and the sensitivity of various side injury parameters on NCAP rating assessment. The federal side impact regulation FMVSS 214 made very stringent by adding oblique pole impact in addition to moving deformable barrier (MDB) test. Though the vehicle velocity is less in oblique pole test, the dynamic intrusions are more which causes severe injury for 5th and 50th %le occupants than MDB test. It was observed that typical injury parameter in side impact requirements is the thorax compression than other injuries, because it is very sensitive than Pelvic, Abdomen regions. To meet these critical injury requirements in side impact, the optimal side restraint system is mandatory in order to develop a safer vehicle with high NCAP score. The side restraint system includes side airbags (thorax and curtain), Hip pusher block/foam padding, door trim arm rest, seat belts and seats.
Technical Paper

UV-Curable Primer-cum-Paint System for Mild Steels based on Sol-Gel Coating Technology

2009-12-13
2009-28-0052
Sol-based coatings derived from organically modified silanes and metal alkoxides have been investigated for the past two decades for their applicability as barrier coatings for corrosion protection of stainless steels and mild steels. Colored sol-gel coatings can also be generated by the addition of pigments. Recently, lot of attention has been given to use of radiation (UV or NIR) curing for densification of protective coatings on metals/steels. In this context, investigations were carried out on the mechanical and corrosion protection properties of UV-curable transparent and colored sol-gel coatings on mild steels for comparison with a painted substrate.
Technical Paper

Unmanned Earth Mover For Hazardous Operations

2009-12-13
2009-28-0061
Personnel from Border Road Organisation, Military Engineers and the Public Works Department are actively engaged in earth removing operation in landslide prone areas and snow clearance tasks in mountainous areas in the North and Northeast of India. These tasks are to be carried out every year seasonally depending on the weather and terrain conditions. These operations are inherently hazardous and risky causing loss of human life. An innovative attempt has been made to modify an earth mover for unmanned operations to facilitate tele-operation from a safe distance. An existing earth mover has been converted to a drive-by-wire mode by providing different electrically powered actuators for the existing control levers. The design for drive-by-wire has been conceived allowing for quick conversion back to manual drive mode.
Technical Paper

Spectroscopic Measurements in Small Two-Stroke SI Engines

2009-11-03
2009-32-0030
This paper demonstrates the potential of optical sensors in the combustion chamber of a small two-stroke SI engine to detect conditions that hinder an optimal combustion process using emission bands and/or emission lines. The primary focus is on the spectroscopic examination of the combustion radiation emissions cycle-by-cycle. For this purpose, spark-ignition type combustion events, as well as the influence of both the air-fuel-ratio and the fuel type, are investigated on a crank angle resolved basis. Furthermore, an assessment of the radiation emissions of the OH, CH and C2 radicals is made. As a next step, the calculation of a temperature profile inside the combustion chamber is attempted by means of the line-emission-method regarding the thermally excited alkaline metals sodium and potassium. These data enable recognition of diffusion combustion and the detection of inadequate mixture quality.
Technical Paper

Numerical Studies on the Effect of Cooling Vent Setting and Solar Radiation on Air Flow and Temperature Distribution in a Passenger Car

2009-12-13
2009-28-0048
Owing to the dynamic life style, considerable time is spent in traveling. Consequently, the demand for thermal comfort of passengers in vehicles has increased. And, to provide thermal comfort, the vehicles are equipped with Heating, Ventilation and Air Conditioning (HVAC) systems. However, the tendency to use more glass in vehicle styling, fuel-economy constraints, environmentally safe refrigerants and reduced condenser air flow, particularly at idling conditions, hampers the goal of achieving the desired thermal comfort of passengers. Thus, it is imperative to evaluate the performance of the HVAC units and the effect of their delivery systems to predict the impact on the airflow, temperature distribution and thermal comfort of passengers. CFD simulations have gained importance for such evaluations, which include both steady state and transient calculations.
Technical Paper

Research and Development on the Modular Dummy Model

2009-01-21
2009-26-0056
The modular dummy model is a new concept to represent a crash dummy in computer simulation. The modular dummy model could be a solution with combination of acceptable responses and quick run times. The approach of the modular dummy model is to take an existing standard model and create rigid modules of all major dummy components (Head, Thorax, Pelvis, Femurs, Tibias, Feet, etc.), which are fully interchangeable between deformable and rigid modules. The special run time efficient component models for the neck and lumbar spine are also developed for the modular dummy. Mass and inertial properties of each rigid module are derived from the corresponding deformable part. The joint and connection definitions are shared between the rigid and deformable modules. The users only need to decide and select which modules should be used in order to achieve the best compromise between CPU time and accuracy for the specific application.
Technical Paper

Material Model Development of an Energy Absorbing Foam for Occupant Safety

2009-01-21
2009-26-0088
Different Original Equipment Manufacturers (OEMs) use different Finite Element (FE) codes to perform crash analyses. Primary explicit codes widely used are LS-DYNA, PAM-CRASH and RADIOSS. These codes help rapid evaluation of vehicle design in the preliminary phase, eliminating the need for cumbersome design changes post-physical validation trials. This is more so critical for crash and safety aspects of design. A variety of Energy Absorbing (EA) foams are offered to OEMs to meet the EA performance requirements. Also the FE codes offer a variety of standard material models to the analyst to choose from. The choice of material model is governed by factors such as type of foam under consideration, simplicity of modeling, available material test data, performance objectives, etc. The development of a validated material model is hence a complex task. This paper deals with development and validation of material models of IMPAXX for the FE codes RADIOSS and PAM-CRASH.
Technical Paper

Side System Optimisation with MADYMO and mode FRONTIER

2009-01-21
2009-26-0004
Across the world different regulations are applicable for side impact, each require a different restraint system approach. However it would be much more cost effective to develop one single restraint system suitable for all global requirements. An efficient methodology has been developed to optimize the restraint system for multiple load cases simultaneously, resulting in a restraint system specification that will ensure that global targets are met. The methodology combines the use of testing and efficient numerical simulation to find a solution in the most effective way.
Technical Paper

Performance Evaluation of Bus Structure in Rollover as Per ECE-R66 Using Validated Numerical Simulation

2009-01-21
2009-26-0002
A rollover event is one of the most crucial hazards for the safety of passengers and bus drivers. Deformation in bus body structure seriously threatens passengers' lives. European regulation “ECE-R66” is in force to prevent the catastrophic consequences of such rollover accidents from occurring and thereby ensuring passenger safety for buses and coaches. On similar lines, is bus code is also coming into force in India. These regulations establish the requirements for passenger survival space (residual space) after the rollover incident happens. According to said regulations, certification can be obtained either by full-scale vehicle testing, or by a validated numerical simulation. The numerical simulation for bus rollover can be carried out using the non-linear explicit dynamic code LS-DYNA and the deformed structure obtained from the simulation enables engineers to investigate whether there is any intrusion in the passenger survival space along the entire vehicle.
Technical Paper

Accident Data Collection Methodology for Building a Traffic Accident Database for Tamil Nadu (India)

2009-01-21
2009-26-0008
India is facing the challenge of reducing road accident fatalities, which claim close to 100,000 lives every year. Road infrastructure is slowly improving, but the number of vehicles on the road is rising fast and so is the number of road accidents, which continue to increase year after year. The data collected by law enforcement agencies is not detailed enough to identify causes and develop solutions. Traffic accidents need to be investigated in detail to include specifics concerning crash location, vehicle damage and injuries sustained by road users. The development of such a detailed database requires the co-operation of a number of government and private organizations associated with road traffic collisions. The foundation for data collection activities is a road traffic accident notification network that enables access to accident details, crashed vehicles, and injury reports in a timely manner.
Technical Paper

Frontal System Optimization with MADYMO and mode FRONTIER

2009-01-21
2009-26-0005
Across the world different regulations are applicable for frontal impact, each require a different restraint system approach. However it would be much more cost effective to develop one single restraint system suitable for all global requirements. Flexible and reliable development approach has to be used for quick evaluations of various safety system configurations and conditions. An efficient methodology has been developed to optimize the frontal restraint system for multiple load cases simultaneously, Resultant restraint system specification to specification to meet global targets. The methodology combines the use of testing and MADYMO modelling techniques in combination with advanced DoE (Design of Experiments) analysis to find a solution in the most effective way. An example will be given for a optimised restraint design to meet European and US requirements.
Technical Paper

Dashboard Stiffness Control for Reducing Knee Injury in Frontal Crashes

2009-01-21
2009-26-0006
In frontal crashes, one of the primary reasons for occupant injuries is hard contact with the vehicle interiors. While restraints like airbags, seat belt pre-tensioners etc. help in preventing direct contact of the upper body region; vehicle interiors play a critical role in controlling the lower body region injuries. Knee injuries can be controlled in various ways as follows: Avoiding contact with the dashboard by use of buckle pre-tensioners etc. Using restraints like knee airbags Optimizing the dashboard profile and stiffness at the contact locations All the above options have their own advantages and limitations. This paper explains the effect of dashboard stiffness tuning for controlling knee injuries in a frontal crash. The development methodology and some validation tools are discussed using a case study.
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