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Training / Education

Fundamentals of GD&T for Inspectors - Foundational Level

2022-06-09
This 2-day foundational-level course builds on geometric dimensioning and tolerancing fundamentals and teaches an introduction of how to inspect GD&T requirements.  The course offers an explanation of the geometric symbols, rules, and concepts, the datum system, and how to inspect GD&T requirements using tools from the four categories of inspection tools (CMM; comparison instruments and fixed gages; hand tools and open set up; and production gaging systems).
Training / Education

Introduction to Car Hacking with CANbus

2021-12-07
Vehicle cybersecurity vulnerabilities could impact a vehicle's safe operation. Therefore, engineers should ensure that systems are designed free of unreasonable risks to motor vehicle safety, including those that may result due to existence of potential cybersecurity vulnerabilities. The automotive industry is making vehicle cybersecurity an organizational priority.
Training / Education

High Voltage Vehicle Safety Systems and PPE

2021-10-18
High voltage vehicle safety is a primary concern for every technician or engineer involved in developing, diagnosing or repairing hybrid or electric vehicles. Engineers/technicians working in this field should complete safety training before they interface with hybrid, plug-in or electric vehicles.
Technical Paper

An Investigation of Property Changes of Copper-Free Brake Pads During Wear Testing: Pressure and Temperature Dependence of Pad Modulus, and the Correlation Between Modulus and Friction Coefficient

2021-10-11
2021-01-1276
Earlier publications have demonstrated that pad and disc properties change during storage and also during the SAE J2522 Brake Effectiveness Test Procedure. The current investigation was undertaken to find out how the properties change under milder braking conditions, using the SAE J2707 Wear Test Procedure. A copper-free formulation was selected for the investigation and tested on an inertia dynamometer using a front caliper designed for a passenger car. The pad dynamic modulus changed up or down throughout the test, depending on the test conditions. The pad dynamic modulus, the pad natural frequencies and the disc natural frequencies all decreased by the end of the test. Under high-speed, high-deceleration and high-temperature braking conditions, the pad surface region permanently expands, which results in reduced dynamic modulus and also leads to reduced pad thickness loss as compared with pad weight loss.
Technical Paper

Dynamic Brake Test Stand

2021-10-11
2021-01-1274
Today, inertia dynamometers or roller dynamometers are used for the development and testing of vehicle brakes. However, these testing methods are either entirely unable to simulate dynamical conditions, close to real driving maneuvers, or they can do so approximately only at very high costs. This means that brakes, braking systems and brake-related assistance systems such as the ESC system can ultimately only be tested in a full prototype of the car or before that on hardware-in-the-loop test stands. In the case of the ESC, these test stands have to simulate the behavior of the brake and the surrounding vehicle in real time, then stimulate the interfaces of the ESC sensors accordingly, and finally evaluate the reaction of the ESC system in different situations. The problem here, however, is that the braking system can only be approximated by simulations.
Technical Paper

Chemistry of the Brake Emissions: Influence of the Test Cycle

2021-10-11
2021-01-1300
The reliable chemical characterization of non-exhaust emissions generated by brakes is of fundamental importance in order to provide correct information for source apportionment studies as well as for their toxicological and environmental assessment.[1,2,3] Nowadays, the best option to obtain samples of PM10 emissions composed only by material worn from the tribological interface, i.e. the braking disc (BD) and friction material (FM) rubbing surfaces, is to sample them on suitable collection filters at a dedicated dyno-bench, during a standard braking test cycle.
Technical Paper

Measurement of Particle Dynamics on the Real Vehicle in Different Driving Scenarios with Swarm Sensors

2021-10-11
2021-01-1299
Due to the increase in public attention to non-exhaust emission sources and their impact on human health extensive measurements have been performed in recent years with the aim to establish a consistent and comparable test standard. In particular, the consideration of tyre and brake abrasion is key because of the small and hazardous particle size and because the increasing ratio of electric vehicles only has these non-exhaust emissions. Measurements under controlled and laboratory-like environments, for example with a brake on a dynamometers, lead to attempts of a uniform test standard according to the WLTP. However, a transfer to the real driving environment is not yet feasible because of many external variables, such as wheel housing or atmospheric influences. Typical reference measurement sensors in the vehicle are only suitable to a limited extent for mobile operation due to their size and the necessary measurement infrastructure.
Technical Paper

Investigations on the deposition behaviour of brake wear particles on the wheel surface.

2021-10-11
2021-01-1301
The deposition behavior of brake wear particles on the surface of a rim and the mechanisms involved have not been fully researched. Similarly, it has not yet been answered how high the proportion of particles deposited on the wheel surface is compared with the particles emitted by the brake and what influences this. This information is a prerequisite for evaluating measurements of particle number and particle mass on the inertia dynamometer and comparing them with real emission behavior. The aim of this study is to verify the deposition behavior of brake particles on the surface of wheels. For this purpose, the real deposition behavior is first determined by on-road tests. For particle sampling, collection pads are adapted at different positions of a front and rear axle wheel. In addition to an RDE-compliant test cycle, urban, rural and motorway sections are used to evaluate speed-dependent influences.
Technical Paper

Transfer Film Composition and Characteristics in Copper-Free NAO Brake Pads

2021-10-11
2021-01-1278
Copper-free non-asbestos-organic (NAO) brake pads have been developed to satisfy the copper content regulations in North America. Copper-free NAO brake pads are required to have a stable friction coefficient owing to the electrification of the control systems, as well as to exhibit improved wear resistance to reduce brake dust emissions. Our previous study indicated that the transfer film formed on the rotor surface affects both the friction coefficient stability and amount of wear. In this study, we investigated how different types of inorganic fillers affect the transfer film formation and its composition in a wear test controlled by temperature. It was confirmed that the main component of the transfer film was iron oxide derived from the rotor. Furthermore, the contained components changed according to the appearance of the rotor surface after each wear test.
Technical Paper

Development of a Modeling Approach to Numerically Predict Filtration Efficiencies of Brake Dust Particle Filters

2021-10-11
2021-01-1285
According to the European Environment Agency, air pollution is the biggest environmental health risk in Europe. Since traffic is one of the main contributors of fine dust, technical solutions are necessary to reduce the particulate emission footprint of vehicles. Also the Health Effects Institute hosted recently an international workshop on non-tailpipe emissions. Brake dust filtration concepts have proven to be a promising solution to significantly reduce fine dust emissions from brakes directly at the source. While CFD simulations for inner-ventilated brakes have become state-of-the-art, a holistic models from particle generation and emission to particle dynamics in the vicinity of the brake is not yet available. However, a good modeling approach of particle tracks is essential to predict filtration efficiencies of brake dust particle filters.
Technical Paper

Research on high-efficiency test method of vehicle AEB based on high-precision detection of radar turntable encoder

2021-10-11
2021-01-1273
With the increasingly complex traffic environment, the vehicle AEB system needs to go through a large number of testing process, in order to drive more safely on the road. In order to speed up the development process of AEB and solve the problems of long cycle, high cost and low efficiency in AEB testing, in this paper, a millimeter wave radar turntable is built, and a high-precision detection algorithm of turntable encoder is designed, at the same time, a test method of vehicle AEB based on the detection data of radar turntable encoder is designed. The verification results show that methods described in this paper can be used to develop the vehicle AEB test efficiently.
Technical Paper

Development of Application-tailored Friction Performance of Race Pad Compounds

2021-10-11
2021-01-1282
As a race driver hits the pedal to trigger the braking event, a dynamic load transfer takes place in the car. This is a similar kind of weight transfer experienced on the road while stopping any vehicle abruptly. Modern race cars such as FIA-regulated Grand Touring Car classes GT3 and LMGTE produce a significant aerodynamic downforce at a reasonably high efficiency level. In this type of high downforce race cars, load variations originated by aerodynamics are added onto the mass transfer. The combination of these effects provide a braking effect with this type of cars a highly transient character. At the same time, our customers are facing the challenge of strict technical regulations, usually forbidding brake control systems. In motorsport competition, car performance is of primary priority to help our customers win championships.
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