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Technical Paper

Lining Property Characterizations for an Improved Integration Cascade

2021-10-11
2021-01-1272
New technologies, such as electrified powertrain and autonomous driving solutions, are transforming the automotive industry in such a way that achieving vehicle level performance requirements demands an increasingly intensive and detailed system integration exercise. Validation of the braking system, critical to any vehicle level project, must evolve so that the ever-increasing requirements cascade is answered in a way that ensures the highest level of safety and performance as the industry moves toward a new frontier of features. To support this evolution of integration methodology, critical-to-performance components, such as brake pads, must undergo a transformation in how performance metrics are characterized, communicated, and documented.
Technical Paper

Designing a Next Generation Trailer Braking System

2021-10-11
2021-01-1268
Passenger vehicles have made astounding technological leaps in recent years. Unfortunately, little of that progress has trickled down to other segments of the transportation industry leaving opportunities for massive gains in safety and performance. In particular, the electric drum brakes on most consumer trailers differ little from those on trailers over 70 years ago. Careful examination of current production passenger vehicle hardware and trailering provided the opportunity to produce a design and test vehicle for a plausible, practical, and performant trailer braking system for the future. This study equips the trailer with high control frequency antilock braking and dynamic torque distribution through use of passenger vehicle grade apply hardware.
Technical Paper

Research on Locked Wheel Protection Function of Aircraft Brake System

2021-10-11
2021-01-1269
Locked wheel protection is an important part of antiskid control for aircraft brake control system. Locked wheel protection compares the wheel speed of two or more wheels, if one of the wheels is too slow, locked wheel protection releases the brake pressure on the slow wheel. This work aims to study the control logic for locked wheel protection. Locked wheel protection control logic consists of 3 key factors: paired wheels, active threshold and inhibit velocity. Focus on comparison different options of these 3 factors, all aspects of control logic for locked wheel protection had been expounded in this study. Simulation and calculation analysis is applied for different locked wheel strategies to evaluate the effect. One conclusion is that the greatest wheel speed of the wheel under control shall be set as a reference speed for locked wheel protection. This study provide the basis to design a proper locked wheel protection function of aircraft brake control system.
Technical Paper

Application of Brake System Failed State Performance and Reliability Requirements to Brake System Architecting

2021-10-11
2021-01-1267
The modern braking system in the field today may be controlled by over a million lines of computer code and may feature several hundred moving parts. Although modern brake systems generally deliver performance, even with partial failures present in the system, that is well above regulatory minimums, they also have a level of complexity that extends well beyond what the authors of existing regulations had envisioned. Complexity in the braking system is poised for significant increases as advanced technologies such as self-driving vehicles are introduced, and as multiple systems are linked together to provide vehicle-level “features” to the driver such as deceleration (which can invoke service braking, regenerative braking, use of the parking brake, and engine braking). Rigorous safety-case analysis is critical to bring a new brake system concept to market but may be too tedious and rely on too many assumptions to be useful in the early architecting stages of new vehicle development.
Technical Paper

In-Depth Considerations for Electric Vehicle Braking Systems Operation with Steep Elevation Changes and Trailering

2021-10-11
2021-01-1263
As the automotive industry prepares to roll out an unprecedented range of fully electric propulsion vehicle models over the next few years - it really brings to a head for folks responsible for brakes what used to be the subject of hypothetical musings and are now pivotal questions for system design. How do we really go about designing brakes for electric vehicles, in particular, for the well-known limit condition of descending a steep grade? What is really an “optimal’ design for brakes considering the imperatives for the entire vehicle? What are the real “limit conditions” for usage that drive the fundamental design? Are there really electric charging stations planned for or even already existing in high elevations that can affect regenerative brake capacity on the way down? What should be communicated to drivers (if anything) about driving habits for electric vehicles in routes with significant elevation change?
Technical Paper

Development of an Optimized Rotary Screw Air Compressor for the Electrical Vehicle Air Brake Systems/Suspension Systems on Trucks and Buses

2021-10-11
2021-01-1281
Air brake systems and their reciprocating air compressors are incumbent, legislated, and mature technologies integral to commercial trucks and especially the Class 8 Diesel Semi-Truck industry. The introduction of the Class 8 Electric-Semi Truck (electric-semi) will displace diesel driven trucks over time. The air brake systems and the requirement for an air compressor will not be displaced for the foreseeable future and the requirements will be inherited by the new electric-semi industry. The industry shall have to work hard to optimize the air compressor for this new electric platform that demands high energy density, high efficiency, low mass, excellent NVH management, small space claim, high levels of durability and reliability, low and easy maintenance over a life of 20 years.
Technical Paper

Research on Braking Energy Recovery Strategy of Pure Electric Vehicle

2021-10-11
2021-01-1264
With the increasingly serious global environmental and energy problems, as well as the increasing number of vehicles, pure electric vehicles with its advantages of environmental protection, low noise and renewable energy, become an effective way to alleviate environmental pollution and energy crisis. Due to the current pure electric vehicle power battery technology is not perfect, the range of pure electric vehicle has a great limit. Through the braking energy recovery, the energy can be reused, the energy utilization rate can be improved, and the battery life of pure electric vehicles can be improved. In this paper, a pure electric vehicle is taken as the analysis object, and the whole vehicle analysis model is built. Through the comparative analysis, based on the driver's braking intention and vehicle running state, the braking energy recovery control strategy of double fuzzy control is proposed.
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

Divergence of Thickness Losses and Weight Losses of Disc Pads for Passenger Cars: High-Copper NAOs and Copper-Free Low Mets

2021-10-11
2021-01-1290
The current investigation was undertaken to find out if lighter-weight passenger car disc pads would exhibit wear behaviors similar to pickup truck pads and commercial heavy truck drum linings in terms of the permanent volume expansion of the friction material contact surface region. 2 high-copper NonAsbestos Organic formulations and 3 copper-free LowMet formulations were tested according to the SAE J2522 test procedure. In all cases, the measured pad thickness loss was found to be less than the thickness loss calculated from the weight loss, indicating pad volume expansion in the pad surface region, in full agreement with the results from the pickup truck and heavy trucks. The heataffected swollen/expanded layer ranges from 0.27 to 0.61 mm in thickness depending on the formula and test conditions. Due to the expansion, pad durability projections made from test results based on high temperature city traffic tests can result in underestimating the actual durability.
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.
Technical Paper

Research on Trajectory Planning and Tracking Strategy of Lane-changing and Overtaking based on PI-MPC Dual Controllers

2021-10-11
2021-01-1262
Aiming at the problem of poor robustness after the combination of lateral kinematics control and lateral dynamics control when an autonomous vehicle decelerates and changes lanes to overtake at a certain distance. This paper proposes a trajectory determination and tracking control method based on a PI-MPC dual algorithm controller. To describe the longitudinal deceleration that satisfies the lateral acceleration limit during a certain distance of lane change, firstly, a fifth-order polynomial and a uniform deceleration motion formula are established to express the lateral and longitudinal displacements, and a model prediction controller (MPC) is used to output the front wheel rotation angle. Through the dynamic formula and the speed proportional-integral (PI) controller to control and adjust the brake pressure.
Technical Paper

Energy Saving Speed Planning Prompting System for Commercial Vehicle Driving In Mountain Area

2021-10-11
2021-01-1279
The mountainous roads are very complex and changeable. When commercial vehicles are driving in mountain areas, the using of brakes can not only reduce the fuel economy, but also increase the brake wear. The aim of this system is utilizing the terrain changes of mountainous roads to guide the driver to control the accelerator pedal reasonably through the mutual transformation of kinetic energy and gravitational potential energy for reducing the energy loss caused by braking on downhill road. The theoretical control points of releasing the accelerator pedal on the uphill road are determined based on the road digital elevation model (DEM) information and the vehicle dynamic model.
Technical Paper

Predictive Maintenance of Commercial Vehicle Brakes using Acoustic Monitoring

2021-10-11
2021-01-1280
This study evaluated the performance of a new approach for detecting problems with commercial vehicle brakes based on the analysis of sounds emitted during braking. Commercial vehicle brakes emit ultrasonic energy inaudible to humans as part of the friction process, and the spectral distribution of these sounds is highly dependent on the mechanical condition of the brakes. Data collected from a commercial vehicle fleet found that the acoustic signature changes as friction linings wear. This conforms with the acoustic theory that the resonant frequency of an object increases with its decrease in mass. The use of this information to inform maintenance operations is promising in that the scheduling of visual brake inspections could be based on acoustic wear patterns rather than arbitrary time intervals and the observation of anomalous signals that might indicate more immediate concerns.
Technical Paper

Design and Analysis of a Pneumatically Actuated Drag Reduction System

2021-10-05
2021-01-5080
The main goal of race car aerodynamics is to generate a desired intensity of downforce for the least possible amount of drag. Nonetheless, the balance of the forces under all circumstances due to speed and acceleration is equally important. The modeling was performed using SolidWorks, and the analysis was done both analytically and by means of computational fluid dynamics (CFD) using a flow simulation with STAR-CCM+. The aerodynamics package, which includes the rear wing, front wing, and undertray that help in faster cornering, is analyzed in the full-car analysis. The full-car analysis is done for pitch and yaw. The increase in cornering ability can come from two major aspects: an increase in the aerodynamic downforce and a decrease in the aerodynamic drag of the vehicle. In order to implement the desired aerodynamics package, an airfoil with a predefined profile was selected. The main factor that limits the selection of an airfoil is its effectiveness at low velocities.
Technical Paper

Intelligent Control System of Magnetic-Impulse Parts Processing in Ship Repair Production

2021-10-04
2021-01-5096
Humanity has been interested in magnetism for over 300 years. Many authors have studied the use of applied magnetism to change the properties of products and expand the use of magnetic processing in ship repair production [1, 2]. Experience shows that magnetic pulse processing (MPP) is a simple and economical way to increase the durability of metal-cutting tools, increase the resource of the most worn parts of machines and mechanisms, and increase the durability of friction units, assembly units, and structures during their repair and manufacture. MPP has a number of advantages: simplicity of electromagnetic energy concentration on the product, its rapid accumulation by the material of the working elements of the part, and the efficiency of improving the operational characteristics (processing time is 0.3 ... 2.0 s with insignificant energy consumption).
Technical Paper

Aerodynamic Performance Assessment on Typical SUV Car Model by On-Road Surface Pressure Mapping Method

2021-10-01
2021-28-0188
Aerodynamics of on-road vehicles has come to the limelight in the recent years. Better aerodynamic design of vehicle would improve vehicle fuel efficiency with increased acceleration performance. To obtain best aerodynamic body, the series of design modifications and different testing methodologies must be involved in vehicle design and validation phase. Wind tunnel aerodynamic force measurement, road load determination and computational fluid dynamics were the common methods used to evaluate the aerodynamic behavior of the vehicle body. As a novel approach, the present work discusses about the on-road (Real time) testing methodology that is aimed to evaluate the aerodynamic performance of vehicle body using surface pressure mapping. A 64-Channel digital pressure scanner has been utilized in this work for mapping the pressure at different locations of the typical vehicle body.
Technical Paper

SCV Chassis Performance Optimization Through Parametric Beam Modelling & Simulation

2021-10-01
2021-28-0183
In automotive product development, design and development of the chassis plays an important role since all the internal and external loads pass through the vehicle chassis. Durability, NVH, Dynamics as well as overall vehicle performance is dependent on the chassis structure. Even though passenger vehicle chassis has a ladder frame or a monocoque construction, small commercial vehicle chassis is a hybrid chassis with the cabin welded to the ladder frame. As mileage is critical for sale of SCVs, making a light-weight chassis is also important. This creates a trade-off between the performance and weight which needs to be optimized. In this study, a parametric beam model of the ladder frame & the cabin of the vehicle is created in COMSOL Multiphysics. The structure has been parameterized into the long member & crossmember geometry & sections. The model calculates the first 12 natural frequencies, global stiffness, and weight.
Technical Paper

Optimization of Spring-Damper Orientation in Double-Wishbone Type Suspension Geometry Using Genetic Algorithm in Python

2021-10-01
2021-28-0256
Orientation of the spring-damper system in a suspension geometry is a critical but hidden factor in vehicle performance characteristics. Spring and damper mounting characteristics are the significant factors to ensure proper contact of the tire with the ground, maintaining ride height, minimizing forces on spring, smooth ride, and driver comfort. Determining the spring orientation is conventionally a long and iterative process that involves computational simulations and processing of analytical expressions, which should align with the practical vehicle constraints. Due to numerous possible orientations, the designer would randomly pick the orientation and do the simulation, which reduces the reliability of the solution and the better solutions remain unexplored. This paper proposes a new methodology to optimize spring damper orientation in a suspension geometry using a genetic algorithm in Python Programming Language.
Technical Paper

Weight Reduction of Double Wishbone-Arm Component in the Suspension System of an Automobile using Generative Design

2021-10-01
2021-28-0258
This work uses the Generative Design approach to achieve a weight reduction of the wishbone arm used in the vehicle suspension system. The suspension system of Haynes Roadster an open two-seater club racing car is taken for this study. Detailed calculations were done to understand the dynamic loads acting in the wishbone arm during acceleration, braking, and cornering. The above-calculated loads, material, domain, fabrication techniques are used as design parameters and weight reduction as the objective in the Generative design to obtain a final output. The various design iterations will be proposed by the algorithm based on the parameters and objectives defined. Generative design uses a machine learning approach which is time-saving and also eliminates the need for redoing and refining the initial designs by giving us optimum designs based on our usage as well as manufacturing requirement at the early stage.
Technical Paper

Experimental Study on SS 304 Sheet Metal for Bending Process Optimization using Response Surface Method

2021-10-01
2021-28-0268
Productivity plays a vital role in manufacturing processes as well as in service. Sheet metal bending process is a type of forming process that has been used by the wide range in industries. There are several tangible and intangible factors affecting the production rate during the bending process. Spring back is one of the severe factors which affects the production rate, especially in stainless steel material. The spring back is mostly affected by material properties, sheet thickness, bending radius, die sizes and component geometry. In this paper, the spring back is studied by the effect of various parameters such as rectangle/oblong slots with varying pitch distance and without slots and bending time in the stainless-steel material 304 grade in V-air bending machine. The experimental data are evaluated by means of the Response Surface Method (RSM). Finally, it was observed that explored results have the betterment of the production rate with connection to spring back.
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