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Thermally sprayed engine bores require surface preparation prior to coating to ensure adequate adhesion. Mechanical roughening methods produce repeatable surfaces with high adhesion strength and are attractive for high volume production. The currently available mechanical roughening methods are finish boring based processes which require diameter-specific tooling and significant clearance at the bottom of the bore for tool overtravel and retraction. This paper describes a new mechanical roughening method based on circular interpolation. This method uses two tools: a peripheral milling tool, which cuts a series of concentric grooves in the bore wall through interpolation, and a second rotary tool which deforms the grooves to produce an undercut. This method produces equivalent or higher bond strength than current surface preparation methods, and does not require diameter-specific tooling or bottom clearance for tool retraction.

This paper focuses on finding and analyzing the relevant parameters affecting traffic flow when autonomous vehicles are introduced for ride hailing applications and autonomous shuttles are introduced for circulator applications in geo-fenced urban areas. For this purpose, different scenarios have been created in traffic simulation software that model the different levels of autonomy, traffic density, routes, and other traffic elements. Similarly, software that specializes in vehicle dynamics, physical limitations, and vehicle control has been used to closely simulate realistic autonomous vehicle behavior under such scenarios. Different simulation tools for realistic autonomous vehicle simulation and traffic simulation have been merged together in this paper, creating a realistic simulator with Hardware-in-the-Loop (HiL), Traffic-in-the-Loop (TiL), and Software in-the-Loop (SiL) simulation capabilities.

Autonomous Vehicles (AVs) operate based on image information and 3D maps generated by sensors like cameras, LIDARs and RADARs. This information is processed by the on-board processing units to provide the right actuation signals to drive the vehicle. For safe operation, these sensors should provide continuous high quality data to the processing units without interruption in all driving conditions like dust, rain, snow and any other adverse driving conditions. Any contamination on the sensor surface/lens due to rain droplets, snow, and other debris would result in adverse impact to the quality of data provided for sensor fusion and this could result in error states for autonomous driving. In particular, snow is a common contamination condition during driving that might block a sensor surface or camera lens. Predicting and preventing snow accumulation over the sensor surface of an AV is important to overcome this challenge.

The transportation sector is facing three revolutions: shared mobility, electrification, and autonomous driving. To inform decision making and guide smart transportation system development at the city-level, it is critical to model and evaluate how travelers will behave in these systems. Two key components in such models are (1) individual travel demands with high spatial and temporal resolutions, and (2) travelers’ sociodemographic information and trip purposes. These components impact one’s acceptance of autonomous vehicles, adoption of electric vehicles, and participation in shared mobility. Existing methods of travel demand generation either lack travelers’ demographics and trip purposes, or only generate trips at a zonal level. Higher resolution demand and sociodemographic data can enable analysis of trips’ shareability for car sharing and ride pooling and evaluation of electric vehicles’ charging needs.

Autonomous vehicle operation is dependent upon accurate position estimation and thus a major concern of implementing the autonomous navigation is obtaining robust and accurate data from sensors. This is especially true, in case of Inertial Measurement Unit (IMU) sensor data. The IMU consists of a 3-axis gyro, 3-axis accelerometer, and 3-axis magnetometer. The IMU provides vehicle orientation in 3D space in terms of yaw, roll and pitch. Out of which, yaw is a major parameter to control the ground vehicle’s lateral position during navigation. The accelerometer is responsible for attitude (roll-pitch) estimates and magnetometer is responsible for yaw estimates. However, the magnetometer is prone to environmental magnetic disturbances which induce errors in the measurement.

Autonomous ground vehicles can use a variety of techniques to navigate the environment and deduce their motion and location from sensory inputs. Visual Odometry can provide a means for an autonomous vehicle to gain orientation and position information from camera images recording frames as the vehicle moves. This is especially useful when global positioning system (GPS) information is unavailable, or wheel encoder measurements are unreliable. Feature-based visual odometry algorithms extract corner points from image frames, thus detecting patterns of feature point movement over time. From this information, it is possible to estimate the camera, i.e., the vehicle’s motion. Visual odometry has its own set of challenges, such as detecting an insufficient number of points, poor camera setup, and fast passing objects interrupting the scene. This paper investigates the effects of various disturbances on visual odometry.

With the rapid development of artificial intelligence, the autonomous vehicles (AV) have attracted considerable attention in the automotive industry. However, different factors negatively impact the adoption of the AVs, delaying their successful commercialization. Accretion of atmospheric icing, especially wet snow, on AV sensors causes blockage on their lenses, making them prone to lose their sight, in turn, increasing potential chances of accidents. In this study, two different designs are proposed in order to prevent snow accretion on the lenses of AVs via air flow across the lens surface. In both designs, lenses made of plain glass and superhydrophobic coated glass surfaces are tested. While some researchers have shown promise of water repellency on superhydrophobic surfaces, more snow accretion is observed on the superhydrophobic surfaces, when compared to the plain glass lenses.

The brake pedal is the brake system component that the driver fundamentally has contact and through its action wait the response of the whole system. Each OEM defines during vehicle conceptualization the behavior of brake pedal that characterizes the pedal feel that in general reflects not only the characteristic from that vehicle but also from the entire brand. Technically, the term known as Pedal Feel means the relation between the force applied on the pedal, the pedal travel and the deceleration achieved by the vehicle. Such relation curves are also analyzed in conjunction with objective analysis sheets where the vehicle brake behavior is analyzed in test track considering different deceleration conditions, force and pedal travel. On technical literature, it is possible to find some data and studies considering the hydraulic brakes behavior.

Deformation of the hub, rotor, and the wheel results in lateral run-out of the rotor. The effect of contact surface variations and bolt forces on the deformation is investigated. It is analytically shown that the run-out due to deformation is caused primarily due to the radial and circumferential moments generated in the hub and the rotor due to bolt tightening. Case studies illustrate the interaction between hub, rotor, and the wheel for various surface conditions. Design guidelines are provided to reduce rotor run-out.

Vehicle sensitivity to brake induced vehicle vibration has been one of the key factors impacting overall vehicle quality. This directly affects long term customer satisfaction. The objective of this investigation is to understand the sensitivities of a given suspension, and steering system with respect to brake induced vehicle vibration, and develop possible solutions to this problem. Design of experiment methods have been used for this chassis system sensitivity study. The advantage of applying the design of experiment methodology is that it facilitates an understanding of the interactions between the hardware components and the sensitivity of the system due to the component change. The results of this investigation have indicated that the friction of suspension joints may affect vehicle system response significantly.

High mileage NVH performance is one of the major concerns in vehicle design for long term customer satisfaction. Elastomeric bushings and brake rotors are key chassis components which tend to degrade as vehicle mileage accumulates with time. The degradation of these components normally causes the overall degradation of vehicle NVH performance. In the current paper two categories of problems are addressed respectively: road-induced vibration due to bushing degradation, and brake roughness due to rotor wear. A system integration approach is used to derive the design strategies that can potentially make the vehicle more robust in these two NVH attributes. The approach links together bushing degradation characteristics, brake rotor wear characteristics, the design of experiment (DOE) method, and CAE modeling in a systematic fashion. The concept and method are demonstrated using a production vehicle.

As part of determining the circumstances of a crash, sometimes components or component assemblies are evaluated to identify if they were damaged as a result of the crash or if they lost function prior to the crash. What role the loss of function may have contributed to the crash is useful in determining if they lost function prior to the crash. The causes and conditions for a brake rotor hub separation from the spindle of a vehicle with tapered roller bearing designs are analyzed through both component level testing and full vehicle testing. Laboratory tests were performed on component assemblies where loads were applied to the wheel assembly and the residual damage to the components was documented. In addition, full vehicle testing was conducted to evaluate the effects of a hub and rotor separation on vehicle control and to document evidence on the components. Real world case studies of hub and rotor separations are presented.

One-dimensional single-zone and two-zone analyses have been exercised to calculate the mass fraction burned in an engine operating on ethanol/gasoline-blended fuels using the cylinder pressure and volume data. The analyses include heat transfer and crevice volume effects on the calculated mass fraction burned. A comparison between the two methods is performed starting from the derivation of conservation of energy and the method to solve the mass fraction burned rates through the results including detailed explanation of the observed differences and trends. The apparent heat release method is used as a point of reference in the comparison process. Both models are solved using the LU matrix factorization and first-order Euler integration.

While SAE double inverted flares have been in use for decades, leaking joints continue to be a problem for OEMs in production settings consuming time and energy to detect and correct them before releasing vehicles from the assembly plant. It should be noted that this issue is limited to first-time vehicle assembly; once a flared brake tube joint is sealed at the assembly plant it remains sealed during normal customer usage. From their inception through the late 1980s most brake tubes have been 3/16″ nominal diameter. With the advent of higher flow requirements of Traction Control and Yaw/Stability control systems, larger tubes of 1/4″ and 5/16″ size have also been introduced. While it was known that the first-time sealing capability of the 3/16″ joint was not 100%, leakers were generally containable in the production environment and the joint was regarded as robust.

Compressibility is a common quality metric for friction materials. In addition, it is typically used as an engineering parameter for brake system design and performance. Compressibility (or elastic properties) of the friction material can effect brake roughness, pedal feel, and noise performance. A characterization technique is presented to determine the cyclic compressibility (over ± 1 kN) as a function of preload, temperature, frequency and time. The initial motivation was related to modeling of brake roughness, but applications to pedal feel and brake noise are also explored. For a given semi-metallic material, changing the temperature from 20 to 300°C or the preload from 8 to 4 kN both halve the cyclic compressibility. Less significantly, a change in frequency from 20 to 1 Hz reduces the cyclic compressibility by 10%. Differences between linings are also considered.

Since the technology applied to vehicles is constant increasing, new systems are being developed to improve performance, comfort and safety. The main way to improve safety is to keep the driver informed about unsafe traffic. In this paper we propose the development of an algorithm that works with an Antilock Brake System, in order to keep the driver informed about the distance between the vehicle equipped with this system and another one in front of it, by this way there is more time to make a safe breaking. The interaction between the driver and this method is given by a visual alert system.

Brake system development and testing is spread over vehicle manufacturers, system and component suppliers. Test equipment from different sources, even resulting from different technology generations, different data analysis and report tools - comprising different and sometimes undocumented algorithms - lead to a difficult exchange and analysis of test results and, at the same time, contributes to unwanted test variability. Other studies regarding the test variability brought up that only a unified and unambiguous data format will allow a meaningful and comparative evaluation of these data and only standardization will reveal the actual reasons of test variability. The text at hand illustrates that a substantial part of test variability is caused by a misinterpretation of data and/or by the application of different algorithms.

Successful demonstrations of fully autonomous vehicle operation in controlled situations are leading to increased research investment and activity. This has already resulted in significant advancements in the underlying technologies necessary to make it a practical reality someday. Not only are these idealized events sparking imaginations with the potential benefits for safety, convenience, fuel economy and emissions, they also embolden some to make somewhat surprising and sometimes astonishing projections for their appearance on public roads in the near future. Are we now ready for a giant leap forward to the self-driving car with all its complexity and inter-dependencies? Humans will need to grow with and adapt to the technological advancements of the machine and we'll deeply challenge our social and political paradigms before we're done. Even if we as engineers are ready, is the driving public ready?

Noise source identification has been a subject well studied in the past few years. Automobile manufactures along with specialized supplies have been developed some methods in this matter. The importance of such subject is quite obvious, especially in the auto industry: identify potential problems and point out solutions for NVH. There are several methods of noise source identification widely used. Among them, one can mention "Hotspot Search," which consists of noise intensity measurement, mapping and ranking the relative contribution of each substructure of one body. Another method used, one can point out is the STSF (Spatial Transformation of Sound Fields). It consists of a measurement over a scan plane using a set of microphone array. In this way, a 2D sound field can be transformed in a 3D description and source direction can be identified.

From the brake system point of view the world can be split into comfort and performance markets. This market split evolved historically and reflects local legal requirements, driving style and the customer expectations. Noise, cold judder and brake dust play the dominant role in the perception of the customer on the comfort market. The performance markets call for high friction level and good fade performance. Currently these customer needs can only be satisfied by usage of different pad materials: NAO and Semi Met materials for comfort markets and generally Low Met materials for performance markets. Due to the differences mentioned above, additional brake system development and testing is done (different testing locations for the same brake attribute). Harmonizing testing, usage of the same test location and same test method could save not only the human resources but also decrease the number of prototypes used in the development phases.