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For most car manufacturers, aerodynamic noise is becoming the dominant high frequency noise source (> 500 Hz) at highway speeds. Design optimization and early detection of issues related to aeroacoustics remain mainly an experimental art implying high cost prototypes, expensive wind tunnel sessions, and potentially late design changes. To reduce the associated costs as well as development times, there is strong motivation for the development of a reliable numerical prediction capability. The goal of this paper is to present a computational approach developed to predict the greenhouse windnoise contribution to the interior noise heard by the vehicle passengers. This method is based on coupling an unsteady Computational Fluid Dynamics (CFD) solver for the windnoise excitation to a Statistical Energy Analysis (SEA) solver for the structural acoustic behavior.

An optical sensor for the detection of carbon dioxide concentrations and stable isotope ratios is described. Either a continuous wave, fiber-coupled distributed feedback laser or an external cavity laser is used to pump an optical cavity absorption cell in cw-Cavity Ringdown Spectroscopy (cw-CRDS). This technique exploits the sensitivity enhancements provided by the long effective pathlength from the optical cavity created between two highly reflective mirrors (R>0.9999). The inherently high precision of the technique combined with its rapid data throughput allows for reliable measurements of both concentration and the isotopic composition of the sampled carbon dioxide. Data collected using a prototype of this sensor could be useful for monitoring module occupancy, crew health (through breath tests), and plant growth chambers.

Engine air induction shell noise is a structure borne noise that radiates from the surface of the air induction system. The noise is driven by pulsating engine induction air and is perceived as annoying by vehicle passengers. The problem is aggravated by the vehicle design demands for low weight components packaged in an increasingly tight under hood environment. Shell noise problems are often not discovered until production intent parts are available and tested on the vehicle. Part changes are often necessary which threatens program timing. Shell noise should be analyzed in the air induction system design phase and a good shell noise analytical process and targets must be defined. Several air induction clean side ducts are selected for this study. The ducts shell noise is assessed in terms of material strength and structural stiffness. A measurement process is developed to evaluate shell noise of the air induction components. Noise levels are measured inside of the clean side ducts.

There are many noise sources from the vehicle fuel system to generate noise inside a vehicle. Among them, the pressure pulsation due to the rapid opening and closing of gasoline engine injectors can cause undesirable fuel pulse noise. As the pressure pulsation propagates in the fuel supply line toward to rear end of the vehicle, the pressure energy is transferred from fuel lines to the vehicle underbody through clips and into the passenger compartment. It is crucial to attenuate the pressure pulsation inside the fuel line to reduce the fuel pulse noise. In this paper, a case study on developing an effective countermeasure to reduce the objectionable fuel pulse noise of a V8 gasoline injection system at engine idle condition is presented. First, the interior noise of a prototype vehicle was tested and the objectionable fuel pulse noise is exhibited. The problem frequency ranges of the pulse noise were identified.

With its advantage on the economic and environmental reason the preference of vehicles with diesel engine is growing in the domestic market as well as European market. And automobile makers are enthusiastic in the development of diesel engine vehicles with more comfortable interior atmosphere in order to meet consumers' requirements. Generally, when compared with gasoline engine, diesel engine has much bigger vibratory input to the mounting structure and produces higher level in interior noise and body vibration. In this paper, the improvement of NVH quality at the idle state of an SUV car with DI diesel engine has been achieved through tuning engine mounts based on TPA (Transfer Path Analysis) for low frequency vibration and interior booming noise.

The serious highway accidents related to heavy-duty trucks were caused mainly by absent-minded conditions of drivers, according to an investigation of highway accidents in Japan. Thus, a collision avoidance warning system has been developed. A laser radar sensor detects the distance to a reflector of the target vehicle. Together with information of the own vehicle speed detected by a magnetic pick-up, a microcomputer assesses the risk of a rear-end collision and provides warning when a dangerous condition has developed. Warning suppresion is considered in unnecessary situations, such as driving in curves, driving at constant speed and distance, and driving at low speed. The system was installed on a heavy-duty truck, and a system evaluation test was carried out on proving grounds and highways. As the result, false alarms created by reflectable objects located adjacent to the road and unnecessary warning could be sufficiently suppressed, and the system was found to be useful.

Sports car sound quality regularly has two conflicting targets, meeting customer's expectations for interior noise and enhancing the driving experience whilst complying with exterior noise legislation. To help with this balancing act acoustics engineers have an ever growing arsenal of tools to choose from. The conventional sound character development approach would typically involve the tuning of existing vehicle systems, primarily the air-intake and exhaust system. Increased flexibility to interior noise sound character tuning has been offered by the development of sound enhancement devices. The number of sound enhancement devices now commercially available has grown significantly in recent years but the systems can be broadly split into two main categories. Passive systems such as intake sound generators that aim to boost the levels of existing noise sources and more recently the advent of electronic sound enhancement through loud speakers and inertia shakers.

Light detection ranging (LiDAR) is commonly used to make high-resolution maps by using ultraviolet, visible, or near-infrared light to image objects. It can target a wide range of materials, with many applications, such as in surveying and accident reconstruction. LiDAR-like systems combine laser-focused imaging with the ability to calculate distances by measuring the time for a signal to return using various electronic sensors. LiDAR data capturing has been conducted and verified from many types of equipment manufacturers, however, little research has compared the FARO Terrestrial Laser Scanner and the LiDAR sensor of an iPad Pro. This study compares these two types of equipment addressing ease-of-use, effectiveness, and cost; where the Terrestrial Laser Scanner will be the control for this study. A statistical evaluation was performed of LiDAR data acquired from nine damaged vehicles and one undamaged vehicle.

Valve timing strategies aimed at producing internal exhaust gas re-circulation in a conventional spark ignition, SI, engine have recently demonstrated the ability to initiate controlled auto-ignition, CAI. Essentially the exhaust valves close early, to trap a quantity of hot exhaust gases in-cylinder, and the fresh air-fuel charge is induced late into the cylinder and then mixing takes place. As a logical first step to understanding the fluid mechanics, the effects of the standard and modified valve timings on the in-cylinder flow fields under motored conditions were investigated. Laser Doppler anemometry has been applied to an optical engine that replicates the engine geometry and different valve cam timings. The cycle averaged time history mean and RMS velocity profiles for the axial and radial velocity components in three axial planes were measured throughout the inlet and compression stroke.

The vast majority of products contain joints, therefore, joining technology is key to the strategic implementation of new materials. This paper considers three innovative solutions to industrial problems ClearWeld™ A recently developed technique for laser welding materials, creating a joint almost invisible to the human eye. AdhFAST™ This novel, three-in-one fastener, allows adhesive to be injected through the middle of the device whilst retaining the joint and controlling bondline thickness Vitresyn™ Transparent plastics such as polycarbonate and acrylic have the potential to replace glass in a number of applications, car headlamps and spectacle lenses for example. However, these plastics are relatively soft materials and need protection against abrasion and scuff damage. This recently developed system gives good protection at acceptable cost

For most car manufacturers, wind noise from the greenhouse region has become the dominant high frequency noise contributor at highway speeds. Addressing this wind noise issue using experimental procedures involves high cost prototypes, expensive wind tunnel sessions, and potentially late design changes. To reduce the associated costs as well as development times, there is strong motivation for the use of a reliable numerical prediction capability early in the vehicle design process. Previously, a computational approach that couples an unsteady computational fluid dynamics solver (based on a Lattice Boltzmann method) to a Statistical Energy Analysis (SEA) solver had been validated for predicting the noise contribution from the side mirrors. This paper presents the use of this computational approach to predict the vehicle interior noise from the windshield wipers, so that different wiper placement options can be evaluated early in the design process before the surface is frozen.

For most car manufacturers, aerodynamic noise is becoming the dominant high frequency noise source (≻500 Hz) at highway speeds. Design optimization and early detection of issues related to aeroacoustics remain an experimental art implying high cost prototypes, expensive wind tunnel sessions, and potentially late design changes. To reduce the associated costs as well as development times, there is strong motivation for the development of a reliable numerical prediction capability. This paper presents a computational approach that can be used to predict the vehicle interior noise from the greenhouse wind noise sources, during the early stages of the vehicle developmental process so that design changes can be made to improve the wind noise performance of the vehicle.

For most car manufacturers, aerodynamic noise is becoming the dominant high frequency noise source (≻ 500 Hz) at highway speeds. Design optimization and early detection of issues related to aeroacoustics remain mainly an experimental art implying high cost prototypes, expensive wind tunnel sessions, and potentially late design changes. To reduce the associated costs as well as development times, there is strong motivation for the development of a reliable numerical prediction capability. This paper presents a computational approach that can be used to predict the vehicle interior noise from the greenhouse wind noise sources, during the early stages of the vehicle developmental process so that design changes can be made to improve the wind noise performance of the vehicle.

A computational process for early stage vehicle shape assessment for automotive front window buffeting and greenhouse wind noise is presented. It is a challenging problem in an experimental process as the vehicle geometry is not always finalized. For example, the buffeting behavior typically worsens during the vehicle development process as the vehicle gets tighter, leading to expensive late counter measures. We present a solution using previously validated CFD/CAA software based on the Lattice Boltzmann Method (LBM). A CAD model with realistic automotive geometry was chosen to simultaneously study the potential of different side mirror geometries to influence the front window buffeting and greenhouse wind noise phenomena. A glass mounted mirror and a door mounted mirror were used for this comparative study. Interior noise is investigated for the two phenomena studied. The unsteady flow is visualized and changes in the buffeting and wind noise behavior are explored.

The ability to assess noise transmitted through seals to cabin interiors early in the design process is very important for automotive manufacturers. When a seal design is inadequate, the noise transmitted can dominate the interior noise, making the wind noise performance of the vehicle unacceptable. This can cause launch delays, increasing costs and risking loss of sales. Designing seals using conventional experimental processes is challenging, since the location and strength of flow noise sources are not known when the seal design is planned. Making changes to the seal system after the tooling stage is expensive for manufacturers as tooling and redesign costs can be considerable. Deliberate overdesign by adding multiple layers of seals in a wide range of locations also can reduce profit by unnecessarily raising part and manufacturing costs.

Induction noise, which radiates from the open end of the engine air induction system, can be of significant importance in reducing vehicle interior noise and tuning the interior sound to meet customer expectations. This makes understanding the source noise critical to the development of the air induction system and the vehicle interior sound quality. Given the ever-decreasing development times, it is highly desirable to use computer-aided engineering (CAE) tools to accelerate this process. Many tools are available to simulate induction noise or, more generally, duct acoustics. The tools vary in degrees of complexity and inherent assumptions. Three-dimensional tools will account for the most general of geometries. However, it is also possible to model the duct acoustics with quasi-three-dimensional or one-dimensional tools, which may be faster as well.

Hot-wire anemometer and laser Doppler velocimeter measurements have been taken in a motored reciprocating engine and compared to assess the validity of hot-wire measurements. The procedure used to account for the sensitivity of the hot wire to changes in the gas temperature is extensively investigated. The results presented show that for the optimum conditions of known flow direction, low turbulence level, and low compression ratio, the hot-wire anemometer can provide useful mean velocity results. Accurate hot-wire turbulence intensity measurements appear to be possible only for the intake and exhaust strokes.

An in-vehicle study was conducted to understand how damping treatments on the floor of a vehicle affect the interior sound in the vehicle. Three differently formulated damping treatments were tested on three similar sport utility vehicles for this purpose. Numerous on-road sound and vibration data were collected under different operating conditions, and were reduced to understand the value of the damping treatment in controlling interior noise caused by powertrain and rolling-tire/road interaction. The paper discusses different data analysis procedures that were used in this study to understand whether there is a damping treatment that performs better than others in spite of variances in test vehicles, and still minimize the adverse influence of other variables that are related to the vehicle performance variation itself.

Contact and collision accidents of automobiles are spatial, and measurements of the path and its dispersion of the automobile and evaluation of operating performance from these measurements are important. There is residual path measuring equipment but there is a demand for more modern equipment. The author has developed equipment to automatically measure the position of an automobile by triangulation using laser beams and to process the data using a computer. This article will explain this equipment and give the results of some experiments in which this equipment was used to test automobile control as application examples.