Automotive Braking Research Articles

AlSi-SiC Composites for Automotive Brake Rotor

This manuscript investigates the Fabrication and Microstructure of Automotive Brake Rotor Made of AlSi-SiC Composites. This work is oriented toward fabrication of automotive brake rotors from Al-9Si and Al-12Si reinforced with 10 and 20% SiC particles using stir-casting method. The brake rotors were subjected to heat treatment. Aging behavior showed that hardness increased with the addition of SiC reinforcements by 104%, comparing to solution treatment condition. Also, the addition of SiC particles accelerates formation of precipitates. Microstructure of brake rotors made of composite revealed uniform distribution of SiC particles, primary phase (⍺-Al) and modified eutectic Si. EDX analysis showed the presence of Al, Mg and O at the interface between matrix and SiC particles.

Thermomechanical analysis of hybrid friction composite material and its correlation with friction braking performance

In the present research work, organic hybrid friction composite materials based on synergistic binary and ternary fibrous combination of ceramic–organic fibers were designed and fabricated especially for automotive braking applications. It encompasses masterbatch of straight phenolic resin, barite, and graphite reinforced with aramid pulp, potassium titanate whiskers and aluminosilicate ceramic fiber amounting to 100% by weight. Fabrication was carried as per formulation design and as per standard industrial procedure using hot molding compression machine followed by post-curing and polishing of pad surface. Thereafter, specimens were characterized for their physical, thermal, mechanical and friction braking performance. The performance parameters (viz. frictional response, friction–fade, friction–recovery, wear, etc.) were evaluated on the Krauss friction testing machine following European Commission for Energy Regulation-90 (ECE R-90) regulations and (pulse velocity wave) PVW-3212 standard test protocol. In this work, thermal characteristics (i.e. DMA and TGA/DTG) of the investigated composites are discussed in details and an attempt has been made to correlate various thermophysical–mechanical characteristics and their possible influence on the braking tribology and wear performance.

Electrothermomechanical Friction of Wet Elements of Automotive Disc-shoe Brakes

Electrothermomechanical Friction of Wet Elements of Automotive Disc-shoe Brakes

LabVIEW-based performance improvement of servo vacuum booster using programmable logic control

The issue of safety is very paramount in any automotive system, especially in automotive braking systems. Nowadays this safety is being somewhat overlooked as the efficient testing is not being performed on the braking systems. Nowadays it is one of the challenging tasks and keeps interest among researchers. In recent days, the researchers focused on designing the braking system which is dependent on servo vacuum booster. In this paper, we intend to aid a model to monitor the servo vacuum booster performance and also to improve the performance of the system. The virtual environment LabVIEW is the tool used to calibrate the system under test. The input stroke which is the replicant of the pedalling motion will be given through the servo motor at the rate required which is helpful to control the Programmable Logic Control (PLC). The parameters under measurement such as performance, jump in and threshold which are required for efficient braking system can be set by PLC programming in RS Logix 5000 software. Meeting the requirements while testing the servo vacuum booster will be considered as effective with no flaws and can be further processed.

A Methodology for the Optimization of Mechanical Properties of Automotive Iron-Casting Brakes using Artificial Neural Networks

In the foundry process of automotive brakes, specialists use a simulation followed by a trial and error method to obtain desired mechanical properties of gray iron casting products. The difficulty of this problem increases due to the numerous process variables. Also, the accuracy of the prediction of mechanical properties using available solidification simulators is limited, which forbids a simulation-driven approach. The current strategy requires then a large amount of trial experiments, which raises the cost of the whole optimization process. In this paper, we present a compound strategy using Artificial Neural Networks (ANN) along with Optimization Engineering to predict the mechanical properties of iron-casted products using a minimum number of physical experiments. A case study evaluates the proposed methodology to accurately predict the mechanical properties of an automotive iron-casting brake component using a minimum amount of physical experimental data.

Theoretical and experimental investigation of non-asbestos friction lining material applied in automotive drum brake

Automotive brakes are the important machine element which provides an artificial frictional resistance to control the speed of an automobile. In the present work, theoretical models for the coefficient of friction between brake drum and friction liner are generated and simulated using MATLAB Simulink. A test set up designed and manufactured according to the brake lining quality test procedure (SAE J661) is used to investigate tribological properties of a non-asbestos friction lining material having 11 different constituents, which is manufactured from one of the brake liner manufacturer. An experiment is designed using response surface methodology (RSM) with vehicle speed, braking force, and sliding distance as the input parameters, whereas coefficient of friction and wear as an output. It is found that vehicle speed is the most significant parameter among the three. Fade and recovery behavior of the friction lining material is also studied and it is found that the developed friction lining material satisfies the criteria specified in SAE J661. Scanning electron microscope (SEM) and energy dispersive spectoscopy (EDS) have revealed the significant surface phenomenon.

A review paper on aluminium-alumina arrangement of composite materials in automotive brakes

Abstract The two level composite of co perpetual aluminium-alumina arrangement is to circumvent SiC particle which provides thermal conductivity. The Wear of CuSiCpMMC material is analysed by utilizing scam electron as well as optical microscopy of wear cicatrices. The tribological inadequacies of the single phase material and categorical function of sundry type of additives were outlined. The results of test withal show is that a friction material with the steel fiber is not well-matched with the Al-MMC disk because of astringent materials as well as erratic friction comportment through descending at elevated temperature.

Characterization of Automotive Brake Discs with Laser-Machined Surfaces

In the automotive and transport industry, braking noise and vibrations are persisting issues and difficult to control. Automotive engineers and researchers are putting considerable effort into overcoming these problems, and significant breakthroughs have been made in this area. In this study, M-shaped grooves were bionically designed and manufactured on the frictional surfaces of four automotive brake discs using a laser machine. Various tests were conducted to characterize the physical and mechanical performance of the modified discs along with their noise and vibration responses. The experimental results demonstrate that discs with laser-machined grooved surfaces have better surface hardness and residual stress reduction than discs with un-grooved surfaces. Significant improvement in the braking performance was observed in terms of disc thickness variation, friction and wear, noise, and vibration reduction. It is concluded that the reduction in braking noise and vibrations is mainly caused by the reduction in the coefficient of friction and wear, increase in damping ratio, and improvement of disc thickness variation of the brake disc by laser surface grooving.

Design of a frictional–electromagnetic compound disk brake for automotives

According to the disadvantages of serious wear and heat fade of friction pad in frequent and high speed braking of friction brakes, and the insufficient power of electromagnetic brakes in low speed braking, a novel frictional-electromagnetic compound disk brake which combines both of these two brake principles is proposed for automotives in this paper. The excitation coils are designed based on the Zhang Yicheng theory model, and the compound brake prototype is manufactured based on the self-made magnetic brake pads and existing automotive brakes. The magnetic field and dynamic of the brake are simulated by using COMSOL Multiphysics software. The frictional–electromagnetic compound brake tests are implemented on the reconstructive disk brake simulation test bench. The experimental results show that the friction braking torque accounts for more than 90% of the compound braking torque in the process of compound braking, and the trend of the change is the same as that of the compound braking torque. When the initial braking speed exceeds 75 km/h, the electromagnetic braking torque does not increase with the increase in speed, instead, it decreases slightly because of demagnetization. The designed frictional–electromagnetic compound disk brake has good braking performance.

Fuzzy Sliding Mode Wheel Slip Ratio Control for Smart Vehicle Anti-Lock Braking System

With the development of in-wheel technology (IWT), the design of the electric vehicles (EV) is getting much improved. The anti-lock braking system (ABS), which is a safety benchmark for automotive braking, is particularly important. Installing the braking motor at each fixed position of the wheel improves the intelligent control of each wheel. The nonlinear ABS with robustness performance is highly needed during the vehicle’s braking. The anti-lock braking controller (CAB) designed in this paper considered the well-known adhesion force, the resistance force from air and the wheel rolling friction force, which bring the vehicle model closer to the real situation. A sliding mode wheel slip ratio controller (SMWSC) is proposed to yield anti-lock control of wheels with an adaptive sliding surface. The vehicle dynamics model is established and simulated with consideration of different initial braking velocities, different vehicle masses and different road conditions. By comparing the braking effects with various CAB parameters, including stop distance, braking torque and wheel slip ratio, the SMWSC proposed in this paper has superior fast convergence and stability characteristics. Moreover, this SMWSC also has an added road-detection module, which makes the proposed braking controller more intelligent. In addition, the important brain of this proposed ABS controller is the control algorithm, which can be used in all vehicles’ ABS controller design.

Superior heat conduction and viscous effect in FeNi complex nanofluids under external stimulus

Magnetic nanofluids have immense potential to increase heat transport and viscous effect under magnetic field. In the present work, bimetallic FeNi nanoparticles are dispersed in two types of conventional fluids, namely, heat transfer oil (HTO) and ethylene glycol (EG), to formulate the nanofluids. The inducement of a magnetic field on thermal conductivity and viscous effect has been reported. Experimental findings reveal the augmented thermal transport by conduction and viscous effect in the presence of an externally applied magnetic field for the formulated nanofluids. Thermal conductivity is found to be enhanced up to a critical magnetic field; beyond the critical magnetic field, a gradual drop is observed. The highest magnitude of thermal conductivity is found to be ∼0.49 W/m K and the respective enhancement of 222% with respect to the base fluid at the critical magnetic field of ∼700 G at 7 vol. % for the sample of FeNi/HTO. The maximum dynamic yield stress and viscosity values achieved are ∼11 kPa and ∼2238 Pa s, respectively, at 7 vol. % and 12 000 G magnetic field for the sample of FeNi/HTO. Thus, a strong influence of magnetic field on the tendency of chain formation in magnetic nanofluids is observed. This leads to amplify the thermal transport and viscous effect in the fluidic system enormously. The findings of the present work are expected to greatly benefit the fields of thermal conduction and viscous behavior and contribute to future smart fluid applications for automotive components such as automotive brakes, clutches, and dampers.

Controlling Friction With External Electric or Magnetic Fields: 25 Examples

Studies of the fundamental origins of friction have undergone rapid progress in recent years, providing valuable information on the relative contributions of electronic, magnetic, electrostatic and phononic dissipative mechanisms. They are now evolving into methods that allow active control of nano and/or meso scale friction through tuning of magnetic and electric fields external to the contact. These methods constitute an area of rapidly growing interest, as they address one of tribology’s present day grand challenges: achieving in situ control of friction levels without removing and replacing lubricant materials situated within inaccessible confines of a contact. In this minireview, 25 examples of electromagnetic tuning of friction are overviewed, with examples spanning atomic to macro scale systems to demonstrate the variety and versatility of approaches that have been reported in the literature. Applications include, but are not limited to triboelectric generators, geological drilling, automotive braking and efficiency, spacecraft systems, biological systems and magnetic spintronics. Experimental methods for measuring the impact of electric or magnetic fields on friction include AFM, SFA, QCM, pin-on-disk, hard disk head- substrate, MEMS and NEMS based tribometers, and optical spectroscopies. Computational and theoretical approaches include analytic, equilibrium and nonequilbrium Monte Carlo simulations.

Research on Control Unit of Motor Drive Brake Actuator

It can be said that the core of car safety is the car brake and its control system. Along with the development of the car, the car brake and its control system has undergone many changes, from rubber friction braking solely relying on manpower to the later pneumatic brake system, hydraulic brake system and so on. Among them, the hydraulic brake system is the most widely used. With the continuous advancement of technology, electric drive machines are widely used in vehicles. Research on electric power assisted hydraulic brake systems has become a hot research topic in recent years, as autonomous driving and driverless. Essential and key components are the inevitable trend and the best solution for the next generation of automotive braking systems. This study describes a control unit for a motor-driven brake actuator that analyzes its role, structure, and advantages in an electric-assisted hydraulic brake system.

Role of the friction layer formed on the brake lining surface in friction stabilization for automotive brakes

This study highlights the frictional behavior of the disc brake interfaces and microstructure of the friction layers (FL) and transferred materials (TM) on the tribopairs. The designed dynamometer was utilized to evaluate the frictional performance of the disc brake materials during dry sliding under different braking events (applied loads and speeds). The morphological properties of the brake lining and disc surfaces were examined by EPMA, FESEM, EDS, 3D surface profilometry and Raman spectroscopy to illustrate the FL, TM and wear mechanisms. The tribo-braking results exhibited that the friction coefficient (FC) increased with increasing the applied load. This is due to the fact that, at high applied loads, the actual contacting area of the friction pair is increased resulting in the growth of the secondary contact plateaus and flattening of primary contact plateaus that help the enrichment of the FL. Whilst, the initial stop-braking speeds did not hugely affect the FC. Eventually, the formation and destruction of the FL showed a significant role in controlling the brake friction behavior. The formation of the FL increases the frictional stabilization.

ANÁLISIS DEL CAUDAL EN UN DISCO DE FRENO AUTOMOTRIZ CON ÁLABES DE VENTILACIÓN TIPO NACA 66-209, UTILIZANDO VELOCIMETRÍA POR IMÁGENES DE PARTÍCULAS

The automotive braking system must meet a complex set of requirements, among which safety is the most important, which is based on the function of the geometric arrangement and the type of material. The objective of this work is to propose a new geometric arrangement for the optimization of the air flow in an automotive brake disc, considering ventilation pillars founded on aerodynamic profiles type NACA 66-209. To support this design proposal, a 1: 1 scale prototype was made by means of additive manufacturing and an installation was also designed, which allows the assembly of the disk to measure the velocity field generated in the suction and discharge zone through the use of the Velocimetry by Particle Images (VPI). Validation of the geometric arrangement was performed under five (5) angular velocity conditions: 541, 641, 741, 841 and 941 rpm. The results obtained from the optimization of air velocity in the discharge zone of 0.1151 and 0.2317 m/s at 35 rpm. The results show the importance of experimental designs with which the geometry of self-ventilated disc brakes can be improved, thus guaranteeing the efficiency and safety of the system.

Effect of Nano Solid Lubricant in Automotive Brake Lining

Automotive brake pads consist of components that form materials such as binders, friction modifiers, reinforcing materials, lubricants and fillers. Factors such as particle size, morphologies, chemical and structural properties of the materials that make up the brake lining composites affect the stability and performance of the lining. In this study, effect of nano-sized graphite used as solid lubricant among brake lining materials on tribological properties was investigated. Three different specimens containing 3, 6 and 9 wt.% nano-sized graphite produced by powder metallurgy method. The specific wear rates and friction coefficients of specimens were obtained by using pin-on-disc type tribometer. The results showed that usage of nanomaterials in brake lining composites improved braking performance significantly. Additionally, it was observed that amount of graphite affected wear and friction properties of brake linings.

Friction hysteresis and subsequent wear mechanism of clay-based phenolic composites under cyclic load

Abstract Friction composites based on different allumino-silicate (i.e. halloysite, montmorillonite and wollastonite) have been developed for automotive brakes to investigate the relative contribution of the clay-minerals as a replacement of MgO and BaSO4 separately. The effect of the cyclic load on friction-hysteresis and wear behavior of the composites are comparatively evaluated with clay free compositions (with and without MgO and BaSO4). The general characteristics of the friction hysteresis under cyclic load reveal three distinct phases i.e. μ build-up, μ-decay, and μ-unloading. It is found that halloysite being less effective in debris compaction manifests minimum friction hysteresis loss, whereas the montmorillonite based composites are characterised with maximum hysteresis loss due to the difference between μ-level during loading and unloading in presence of MgO as an abrasive. Wollastonite with the relatively minimum area to volume ratio manifests inefficient reinforcement in the tribo-film thus debris formation and subsequent third body abrasion demonstrates undulating μ-level with maximised μ-average. Worn surface morphology illustrates the presence of plastically deformed distorted surface with fiber dislodging and pit formation for composites containing halloysite, suggesting extensive abrasion. Soft regimes over the worn surface as a result of debris compaction and smooth morphology is the characteristics of montmorillonite based worn surfaces. Easy removal of the tribo-layer due to shear and heat accumulation results in discontinuous transfer film over the worn surface in presence of wollastinite, where MgO is effective in debris compaction. An almost similar level of volumetric wear for all the composites with circular and transverse cracks over the surface is due to the persistence of fatigue wear-mechanism under cyclic load.

Digital Twin of an Automotive Brake Pad for Predictive Maintenance

Abstract The traditional manufacturing industry is being challenged globally with the comprehensive growth in digital technologies and big data. Digital Twin (DT) technology is one such vision that refers to a comprehensive physical and functional description of a physical component, product or an entire system with all the operational data. The Digital Twin of a product establishes a physical-virtual connection that paves way to real time monitoring all through the entire life cycle of the related product. This paper describes the advance of a digital twin that supports in the predictive maintenance of an automobile brake system. As a proof of concept, brake pressure was measured at different vehicle speeds using ThingWorx Internet of Things (IoT) platform. The data captured using the platform was used to demonstrate the prediction of brake wear using the CAD model implemented in CREO Simulate.

High-Precision Modulation of a Safety-Critical Cyber-Physical System: Control Synthesis and Experimental Validation

As a typical safety-critical cyber-physical system (CPS), the brake-by-wire (BBW) system, which provides improved control and enhanced performance, shows promise as an automotive braking scheme. In addition, the BBW system can be incorporated into all types of vehicles, including conventional vehicle with an internal combustion engine, electrified vehicles, and intelligent vehicles. However, the high cost and complexity of existing BBW systems limit their usage. In this paper, we consider a novel BBW system that we have developed, which has the advantages of having a simple structure and low cost. To enhance control accuracy of hydraulic pressure modulation and reduce noise, two pressure modulation methods, namely, the hydraulic pump−based pressure modulation (HPBPM) and the closed-loop pressure-difference-limiting (CLPDL) modulation, were proposed. So as to demonstrate the performance of the proposed approach, hardware-in-the-loop (HiL) experiments were conducted. The experimental results indicated that the proposed BBW system, which incorporates the CLPDL control method, appears to be a promising system in terms of the overall performance, including control performance, noise reduction, and system simplification.

Nanocomposite Kaolin/TiO2 as a Possible Functional Filler in Automotive Brake Pads

An automotive friction brake pad is a complex system consisting of several components with unique and balanced properties related to operation conditions. There are efforts to develop brake pads with longer lifetime and better friction performance and wear properties. Those properties are related to composition of the pads, and therefore, new materials are being evolved. Tuning the friction and wear properties can be achieved with the selection of a functional filler and optimizing its amount in a formulation of friction brake pad. Laboratory-developed and laboratory-prepared nanocomposite material kaolin/TiO2 (KATI) has been introduced to formulation of the commercially available automotive low-steel brake pad. Kaolin was utilized as a matrix for anchoring TiO2 nanoparticles. New unused pads and pads after AK master, a standard dynamometer testing procedure of friction performance, were investigated using light and scanning electron microscopy providing information on the structure and its changes after the friction processes. Moreover, MTK wear test was used to compare wear rate of the newly developed pad with the reference low-steel pad. Improved durability of the brake pad formulation has been observed together with sufficient friction performance. Microscopic analysis shown homogenous distribution of the KATI nanocomposite in the friction layer. From the obtained results, it can be assumed that the new formulation is promising regarding to the life cycle of the pads and reduction of wear rate and thus potential production of wear particulate emissions.