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SAE International

2021-10-18
SAE Brake Colloquium remains gathering place for leading industry experts gather share advancements innovations do business around brake systems friction materials

SAE International

2021-10-18
The ADAS to Automated Driving Digital Summit will address the recent advancements in connectivity, system engineering and machine learning systems that are transforming ADAS and automated vehicle systems research creating a new era of integrated and cooperative automated driving.
Technical Paper

Systems of Automatic Brake Torque Reduction on the Wheels of One Axle of the Car

2021-10-11
2021-01-1266
Braking mechanisms have the most variation in performance of all of the elements of the braking system. Instability of braking torques on the wheels of one axle of the vehicle leads to the appearance of the braking forces unevenness, and then- to the vehicle skidding during braking. At one time, the appearance of open-type disc brakes made it possible to reduce the unevenness of the braking forces on the sides of the car due to their higher characteristics of energy intensity and stability. However, the lack of feedback between the left and right disc brakes mounted on the same axle of the vehicle does not allow reducing the unevenness of the braking forces to an acceptable minimum. The authors of the work studied and proposed several systems for automatic reduction of the braking torques unevenness for braking mechanisms mounted on the wheels of one axle.
Technical Paper

Potential and Challenges for Application-Specific Friction Characteristics of Race Brake Pads

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.
Technical Paper

Analysis of the Effect of the Wedged Type Brake Caliper Piston on Brake Drag

2021-10-11
2021-01-1293
Recently, there’s a massive flow of change in the automotive industry with the coming era of electric vehicles and self-driving (autonomous) vehicles. The automotive braking system field is not an exception for the change and there are not only lots of new systems being developed but also demands for researches for optimizations of conventional brake systems fitting to the newly appeared systems such as E-Booster and Electric Motor Brake (EMB) Caliper. Taking the Electric Motor Brake Caliper for example, it is considered as a very important and useful system for autonomous vehicles because the motor actuator of the caliper is much easier to control with ECUs compared to the conventional hydraulic pressure system. However, easy of control is not the only thing that excites brake system engineers.
Journal Article

Detailed Modeling of Pneumatic Braking in Long Combination Vehicles

2021-08-23
Abstract A detailed model for pneumatic S-cam drum brake systems is developed and integrated into a multibody dynamic model for a 33-ft A-double long combination vehicle (LCV). The model, developed in TruckSim®, is used to study the dynamics of LCVs during straight-line braking at various speeds. It includes the response delay in braking that occurs from the time of application to when the brakes are applied at the drum for all axles. Additionally, the model incorporates an accurate characterization of brake torque versus chamber pressure at different speeds, along with the anti-lock brake system (ABS) dynamics, to yield an accurate prediction of the vehicle’s deceleration during braking. The modeling results are compared with test results at speeds ranging from 20 mph to 65 mph on dry pavement. A close match between the model’s prediction and test results is observed.
Standard

Dynamometer Global Brake Effectiveness

2021-08-02
WIP
J2522

This SAE Recommended Practice defines an Inertia Dynamometer Test procedure that assesses the effectiveness behavior of a friction material with regard to pressure, temperature and speed for motor vehicles fitted with hydraulic brake actuation.

The main purpose of SAE J2522 is to compare friction materials under the most equal conditions possible. To account for the cooling behavior of different test stands, the fade sections are temperature-controlled.

Technical Paper

Direct Yaw Control Based on Optimal Longitudinal Tire Forces for 8×8 Combat Vehicle

2021-04-06
2021-01-0261
This paper proposes an active chassis control strategy for an Eight-wheel drive/Four-wheel steering (8WD/4WS) combat vehicle, where only the first and second axles’ wheels are steerable, while the third and fourth axles’ wheels are non-steerable. Utilizing torque vectoring and differential braking control to improve its lateral dynamics at limit handling. Due to the non-linear characteristics of the tires and its friction limit, the vehicle may exhibit instable behavior during cornering maneuvers. It is well known that the tire longitudinal and lateral forces are shared, if longitudinal forces increased, slip ratio will increase and causing reduction in lateral forces that may cause the vehicle to drift out or spinning. Accordingly, the tires forces need to be optimally distributed based on vertical loads for each tire to prevent it from reaching the friction limit based on Friction Ellipse Theorem.
Technical Paper

Turbocompounding the Opposed-Piston 2-Stroke Engine

2021-04-06
2021-01-0636
This paper presents analytical research conducted into the level of fuel consumption improvement that can be expected from turbocompounding a medium-duty opposed-piston 2-stroke engine, which is part of a hybridized vehicle propulsion system. It draws on a successful earlier study which showed a non-compounded opposed-piston engine to be clearly superior to other forms of 2-stroke engine, such as the widely adopted uniflow-scavenged poppet valve configuration. Electrical power transmission is proposed as the method of providing the necessary variable-speed drive to transmit excess turbine power to the system energy storage medium. The work employs one-dimensional engine simulation on a single-cylinder basis, using brake specific fuel consumption (BSFC) as the reportable metric, coupled with positive or negative power flow to the engine from the compounder; this is a variation on an approach successfully used in earlier work.
Technical Paper

Thermal Improvement of Integrated Electromagnetic and Friction Braking System of Trailers

2021-04-06
2021-01-0341
In order to improve the driving safety, an integrated brake system of trailers is proposed, which can solve the problems of insufficient braking force and poor stability when braking. This system realizes the integration of the main braking system and the auxiliary braking system of articulated vehicles, thus avoiding the phenomenon of "folding" and "rollover" during braking. The integrated brake system developed in this paper is mainly composed of friction braking system and electromagnetic braking system. First, the design scheme for the integrated brake system was illustrated based on the system’s working principle and structures. After that, the mathematical model of electromagnetic braking system was derived based on electromagnetic theory. Then, the electromagnetic braking system was simulated by CAE technology, while the magnetic density distribution and braking torque value were studied.
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