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Given the fast changing market demands, the growing complexity of features, the shorter time to market, and the design/development constraints, the need for efficient and effective verification and validation methods are becoming critical for vehicle manufacturers and suppliers. One such example is fault-tree analysis. While fault-tree analysis is an important hazard analysis/verification activity, the current process of translating design details (e.g., system level and software level) is manual. Current experience indicates that fault tree analysis involves both creative deductive thinking and more mechanical steps, which typically involve instantiating gates and events in fault trees following fixed patterns. Specifically for software fault tree analysis, a number of the development steps typically involve instantiating fixed patterns of gates and events based upon the structure of the code. In this work, we investigate a methodology to translate software programs to fault trees.

Can you become a visionary or are you born one? How does a visionary capture an opportunity and makes it a successful business? Are engineers more qualified to solve technical problems or run companies? SAE's "The Visionary's Take" addresses these and many other questions, by talking directly with those who have dared to tackle difficult engineering problems, and create real-life products out of their experience. In these short episodes, Sanjiv Singh and Lyle Chamberlain, respectively CEO and Chief Engineer from Near Earth Autonomy, talk about their experience in creating a brand-new company in the UAV world. Founded in 2011, Near Earth Autonomy brought together a group of engineers and roboticists, looking for unconventional solutions to very hard logistics problems, presenting danger to human life. The answers were developed by pushing technology to a higher level, testing quickly and often, and keeping an open mind to alternative ways of framing engineering challenges.

Can you become a visionary or are you born one? How does a visionary capture an opportunity and makes it a successful business? Are engineers more qualified to solve technical problems or run companies? SAE's "The Visionary's Take" addresses these and many other questions, by talking directly with those who have dared to tackle difficult engineering problems, and create real-life products out of their experience. In these short episodes, Sanjiv Singh and Lyle Chamberlain, respectively CEO and Chief Engineer from Near Earth Autonomy, talk about their experience in creating a brand-new company in the UAV world. Founded in 2011, Near Earth Autonomy brought together a group of engineers and roboticists, looking for unconventional solutions to very hard logistics problems, presenting danger to human life. The answers were developed by pushing technology to a higher level, testing quickly and often, and keeping an open mind to alternative ways of framing engineering challenges.

This technical paper collection contains 53 technical papers. Topics covered include engine exhaust aftertreatment and integration; hybrid vehicle integration and optimization; powertrain and drivetrain NVH; advanced transmission and driveline component design; diesel engine system design; fuel economy; alternative fuels; and advanced engine component design.

With the introduction of advanced digital road maps, which include information on the slope and curve radius of the highways, predictive control for standard and hybrid commercial vehicles, based on these maps, is about to be released by the vehicle manufacturers. For example, intelligent predictive cruise control has been announced for introduction in 2012 by Scania and Daimler. In addition, hybrid commercial city buses like MAN's Lion's City Hybrid have already been implemented. But the question remains about the type of vehicle suitable for the implementation of predictive intelligent concepts, due to the high investment cost compared to the sometimes relatively low operating cost savings.

Catalysts and filters continue to be applied widely to meet particulate matter regulations across new and retrofit diesel engines. Soot management of the filter continues to be enhanced, including regeneration methodologies. Concerns regarding in-cylinder post-injection of fuel for active regeneration increases interests in directly injecting this fuel into the exhaust. Performance of secondary fuel injection layouts is discussed, and sensitivities on thermal uniformity are measured and analyzed, providing insight to packaging challenges and methods to characterize and improve application designs. Influences of end cone geometries, mixers, and injector mounting positions are quantified via thermal distribution at each substrate's outlet. A flow laboratory is applied for steady state characterization, repeated on an engine dynamometer, which also provides transient results across the NRTC.

This manuscript provides a review of different types and categorization of the chassis dynamometer systems. The review classifies the chassis dynamometers based on the configuration, type of rollers and the application type. Additionally the manuscript discusses several application examples of the chassis dynamometer including: performance and endurance mileage accumulation tests, fuel efficiency and exhaust emissions, noise, vibration and harshness testing (NVH). Different types of the vehicle attachment system in the dynamometer cell and its influences on the driving force characteristics and the vehicle acoustic signature is also discussed. The text also highlights the impact of the use of the chassis dynamometer as a development platform and its impact on the development process. Examples of using chassis dynamometer as a development platform using Vehicle Hardware In-the-Loop (VHiL) approach including drivability assessment and transmission calibrations are presented.

The present competitive market scenario and customer requirements demand for improved NVH quality and to meet statutory norms without increased cost. When gears are used for power transmission, gear noise is of particular concern. The noise may be created due to harmonics of the rotating and meshing internal components. This has a significant effect on the overall vehicle sound quality. Various factors contribute to gearbox noise. Some of them include shaft misalignments, gear geometry, lubrication, bearings and loose mountings. Hence it is essential to study which factors contribute to the gearbox noise and to develop countermeasures for the same. Although a number of factors may contribute to gear noise as mentioned, the scope of this paper is limited to the effect of gear geometry alone on the gearbox noise.

Exhaust noise and note are key factors when deciding which high-performance vehicle to buy. Cadence and tone of the exhaust can determine whether a customer is willing to make a purchase. To make sure the exhaust note is desirable, manufacturers must make several prototypes with each subjected to extensive testing, tuning, and customer surveying. This process can be expensive and time consuming. However, even after such processes, the final design may not be well received by consumers. Utilizing computer aided engineering (CAE), specifically computational fluid dynamics (CFD) can provide a financially viable and technically sound solution to this issue. Recent developments in CAE software have allowed for capturing the effects of aeroacoustics in exhaust systems and reproducing the acoustic signatures as well as a physical exhaust note.

In tire development, the dynamic tire-road contact forces are an important indicator to assess structure-borne interior cabin noise. This type of noise is the dominant source in the frequency range from 50-450 Hz, especially when rolling with constant angular velocity on a rough road. The spatial force distribution is difficult or sometimes even impossible to simulate or measure in practice. So, the use of an inverse technique is proposed. This technique uses response measurements in combination with a digital twin simulation model to obtain the input forces in an inverse way. The responses and model properties are expressed in the time domain, since it is specifically aimed to trace back the impact locations from road surface texture indents on the tire. In order to do so, the transient responses of the travelling waves as a result of these impacts is used. The framework expresses responses as a convolution product of the unknown loads and impulse response measurements.

To improve overall customer experience, it is imperative to minimize the noise levels inside agricultural equipment cab. Up-front prediction of acoustic performance in product development is critical to implement the noise control strategies optimally. This paper discusses the methodology used for virtual modeling of a cab on agricultural equipment for prediction of interior noise. The Statistical Energy Analysis (SEA) approach is suitable to predict high frequency interior noise and sound quality parameters such as articulation index and loudness. The cab SEA model is developed using a commercial software. The structural and acoustic excitations are measured through physical testing in various operating conditions. The interior noise levels predicted by the virtual model are compared with the operator ear noise levels measured in the test unit. The resultant SPL spectrum from SEA correlates well with the test.

Noise & Vibration refinement of automotive vehicles is becoming important parameter due to its influence on environmental aspect and comfort perceived by occupants. NVH parameters are driving factors in current vehicle design strategy. Drivers comfort is extremely important, and driver’s expectations from commercial and heavy-duty trucks are as good as refined passenger cars. Other trends in commercial vehicle segment such as engine downsizing, weight, cost reduction and meeting stringent emission norms have influenced vehicle design dynamics. These parameters are critical and often contribute to vehicle NVH issues. Considering these new trends in commercial vehicle segment, it becomes challenging for an NVH engineer to provide optimized solutions. NVH issues could be related to the various subsystems such as driveline, axle, transmission steering wheel etc. in the vehicle and its resonant frequencies.

India contributed to 11% of the global road accidents and was ranked 1st among road deaths according to the latest World Health Organization (WHO) report 2018. Indian National Highways (NH) is a meagre 5% of the country’s road network but accounts for 55% of the road accidents and 61% of the road deaths. Majority of the freight traffic is ferried by Commercial Vehicles (CV) or trucks along these highways and this in turn increases the probability of them being involved in a road accident. The country’s economy is forecasted to thrive in the coming years and hence the requirement of CVs is aligned to international categorisation in the supply chain and shall play a pivotal role. In the year 2019, 13,532 road deaths were associated with CV occupants. The trucking industry is an unorganized sector wherein the illegal overloading of vehicles and over-the-limit driving hours pose a serious threat to road users.

Minimizing rattle noises is becoming increasingly important for hybrid and electrical vehicles as masking from the internal combustion engine is missing and in view of the functional requirements of the office-like interiors of next generation automated vehicles. Rattle shall therefore be considered in the design phase of component systems. One hurdle is the modelling of the excitation mechanisms and its experimental validation. In this work we focus on excitation by loose parts having functional clearances such as gear systems or ball sensors in safety belt retractors. These parts are excited by relatively large low frequency displacements such as road-induced movements of the car body or low order rigid body engine vibrations generating multiple impacts with broad band frequency content. Direct measurement of the impact forces is in many cases not possible.

Increasing demands for high fuel efficiency requires imperative light weighting of automotive structure, but this adversely affects the NVH performance since transfer path of noise sources like engine, road, wind to vehicle interior through the panels weakens. Also increasing customer centric approach drives the urge to provide world-class comfort which is cost-effective too. Sound Packaging helps us to optimize this transfer paths through the panel, and can effectively complement efforts of testing team, by reducing the redundant iterations required to conclude to most effective trims to be put on. statistical energy analysis based simulations is employed for carrying out these iterations at the virtual validation gateway itself.

Steering system is responsible for providing a precise directional control to the vehicle. The Hydraulic Power Assisted Steering (HPAS) system is commonly used in passenger cars and commercial vehicles due to low cost. Power steering pump develops and delivers required pressure to provide assistance while steering. It reduces the effort required to steer the vehicle. Steering pump (generally vane type) is a critical part providing hydraulic pressure assistance to rack and pinion or gear box. Basically the hydraulic pump noise can be classified as ‘Moan Noise’ and ‘Whine Noise’. The noise generated by power steering pump pressure pulsation is termed as ‘Moan’ and ‘Whine’ based on operational induce frequency. As power train becomes quieter, it becomes more perceivable at typical engine operating speed range and gives impression of poor refinement and quality.

There is a higher demand for quieter tractors in the agri-industry, as the continued exposure to noise levels have disastrous effects on operator’s health. To meet the world-wide regulatory norms and to be the global market leader, its mandatory to develop the comfortable tractor which meets homologation requirements and customer expectations. Typically, Operator Ear Level (OEL) noise has been evaluated in the test, after First Proto has been made. This approach increases cost associated with product development due to late changes of modifications and testing trails causing delay in time-to-market aspect. Hence, there is a need to develop the methodology for Predicting tractor OEL noise in virtual environment and propose changes at early stage of product development. At first, full vehicle comprising of skid, sheet metals and Intake-exhaust systems modelled has been built using Finite Element (FE) Preprocessor.

This paper focuses on partial encapsulation technique for reducing air-borne noise from the rocker cover of a commercial vehicle diesel engine. Due to increasing awareness, customers demand for improvised NVH (Noise Vibration and Harshness) performance in modern day vehicles. Better NVH performance implies better comfort for passengers as well as vehicle operator. This further increases the driver up time due to reduced driver fatigue. In order to improve NVH performance of existing vehicle and observe different noise and vibration zones, detailed noise and vibration mapping was carried out on one of our vehicle platform. It is observed that engine noise is one of the major contributors for interior noise, apart from road inputs etc.

Small commercial vehicles (SCVs) are the drivers of a major part of India’s indirect economy, providing the most efficient means of transport. With the introduction of BS-VI norms, some major overhauls have been done to the SCV models to meet BS VI norms in challenging timeline for early market entry. This forced to automotive designers towards challenge of cost competitiveness as well as refinement level to survive in this competitive market. This paper explains the systematic approach used to overcome challenges of higher tactile vibrations, higher in-cab noise because of BS VI requirement in 2 cycle engine required for small commercial vehicle. The solutions were need to be worked out without compromising the other performance attributes like total cost of ownership, fuel economy, ease of servicing and cost effectiveness.

In today’s automobile industry refined NVH performance is a key feature and of high importance governing occupant comfort and overall quality impression of vehicle. In this paper interior noise and vibration measurement is done on one of the light truck and few dominant low frequency noise booms were observed in operation range. Modal analysis was done for the cabin at virtual as well as experimental level and few modes were found close to these noise booms. Vibrations were measured across the cabin mounts and it was found that the isolation of front mounts is not effective at lower frequencies. Taking this as an input, the mount design was modified to shift the natural frequency and hence improve the isolation behavior at the lowest dominant frequency. This was followed by static and dynamic measurement of the mounts at test rig level to characterize the dynamic performance and stiffness conclusion.