Refine Your Search

Topic

Author

Affiliation

Search Results

Standard

Communication for Plug-in Vehicles as a Distributed Energy Source

2023-11-06
CURRENT
J2847/3_202311
This SAE Recommended Practice applies to a plug-in electric vehicle (PEV) which is equipped with an onboard inverter and communicates using IEEE 2030.5-2018. It is a supplement to the SEP2 standard, which supports the use cases defined by SAE J2836/3. It provides guidance for the use of the SEP2 distributed energy resource function set with a PEV. It also provides guidance for the use of the SEP2 flow reservation function set, when used for discharging. It is not intended to be a comprehensive guide to the use of SEP2 in a PEV. Note that in this document, SEP2 is used interchangeably with IEEE 2030.5-2018.
Standard

Contacts, Electrical Connector, General Specification For

2023-11-06
WIP
AS39029F
This specification covers the general requirements for removable crimp, solderless wrap, and solder type electrical contacts for use in connectors and other electric and electronic components (see 6.1) with stranded conductor wire. The contacts shall be capable of operating within the temperature range as specified (see 3.1).
Article

‘Zonal’ for the win

2023-11-06
With zonal E/E platforms, standardization and modularization of electronic systems promise cost and weight reductions — and more-advanced vehicle features.
Technical Paper

A Renewed Look at Centralized vs. Decentralized Actuation for Braking Systems

2023-11-05
2023-01-1865
De-centralized brake actuation – that is, brake systems that incorporate individual actuators at each wheel brake location to both provide the apply energy and the modulation of braking force – is not a new area of study. Typically realized in the form of electro-mechanical brake calipers or drum brakes, or as “single corner” hydraulic actuators, de-centralized actuation in braking systems has already been deployed in production on General Motor EV1 Electric Vehicle (1997) in the form of electric drum brakes and has been studied continually by the automotive industry since then. It is frequently confused with “brake by wire,” and indeed practical implementations of de-centralized actuation are a form of brake by wire technology. However, with millions of vehicles on the road already with “brake by wire” systems - the vast majority of which have centralized brake actuation – the future of “brake by wire” is arguable settled.
Technical Paper

Optimization of Insulating Material Selection for Effective Squeal Noise Damping

2023-11-05
2023-01-1870
Squeal noise phenomenon in disc brakes is a complicated dynamic challenge which brake manufacturers have confronted for decades. The most prevalent technique apprehended by the brake manufactures is to simulate the braking conditions using a noise dynamometer. This is a well-established, expensive technique which is time-consuming. The objective of this paper is to understand the phenomenon of brake squeal, modal coupling and publish an analytical approach to predict a suitable damping material and thereby to optimize the dynamometer tests and time. As the temperature increases the stiffness of the component decreases thereby the resonance frequency tends to decrease. Compressing the pad increases its stiffness and thereby its resonance frequency. Compressibility being inversely proportional to stiffness has direct influence over the frequency response function of the brake components.
Technical Paper

Mitigating of Low Frequency Squeal Noise by Optimize the Pressure Pattern with Shim Geometry in Noise Dynamometer and Corelating to FEA

2023-11-05
2023-01-1871
Despite efforts to reduce disc brake noise occurrence, it remains a significant concern in the automotive industry, particularly in the current era of electric vehicles, where it can be an intermittent issue. There is no standard solution available for every noise frequency, as it depends on various conditions and parameters that need to be experimentally identified and addressed. This paper specifically focuses on addressing low-frequency noise. During dynamic conditions, the contact pressure becomes uneven, leading to uneven pad wear and making the disc brake system susceptible to noise. In noise rigs, the paper selects the most suitable shim and pad geometry based on trials that analyze the interaction between the shim and pad. In conventional practice, shim modification was performed using computer-aided engineering, but obtaining accurate pressure patterns in dynamic conditions with CAE is challenging due to certain assumptions.
Technical Paper

Optimization of Drum Brake System in HCVs Using Two-Way Coupled CFD Approach

2023-11-05
2023-01-1874
The brake systems are given top priority by automotive OEMs in the development of medium and heavy commercial trucks and buses, which can carry increased loads. When trucks and buses are travelling at high speeds or crossing downhill, during braking operations, the friction faces (brake drum and liner) experience a significant rise in temperature due to the conversion of kinetic energy into heat energy within seconds. This lowers the friction coefficient at the interface, resulting in distortions, thermal cracks, hub grease burning, and overheating. Drum brake system designs must be improved and optimized to dissipate more heat from the brake drum assembly and prevent brake failure. Nowadays advance transient numerical simulations assist in the design, development and optimization of the brake system to visualize 3D flow physics and temperature variations throughout the brake duty cycles. In the current study, different Cases of drum brakes to improve cooling efficiency are evaluated.
Technical Paper

Standalone Hill Drive Away Assist

2023-11-05
2023-01-1867
This paper describes a patented, standalone, intelligent Hill Drive Away Assist (HDAA) system, comprising of an electro-mechanical unit, to overcome the hurdles faced by the driver while starting the vehicle on a gradient. This system can be added as an additional feature in vehicles which have Manual or Automatic Transmission and are equipped with or without ABS (Antilock Braking System). The developed system is available as Hill Start Assist (HSA) feature in vehicles with Electronic Stability Control (ESC). This HSA functionality is achieved through Drive Away Release (DAR) feature in vehicles equipped with Electric Park Brake (EPB). In ABS only vehicles, this feature cannot be achieved with the existing hardware and software. This HDAA can be implemented as a stand-alone system in vehicles without ESC / EPB, thereby reducing the cost of the vehicle while providing the Hill Start feature.
Technical Paper

Sound Source Identification of In-Plane Squeal of Disc Brakes Using Array Microphones and Its Verification by Acoustic Simulation

2023-11-05
2023-01-1869
As the vehicle electrification progresses and the demand for acoustic comfort increases, the NVH performance of brakes becomes more important theme. In-plane squeal of disc brake is one of phenomena that is difficult to countermeasure. In this study, we used array microphones to search for sound sources of in-plane squeal in order to elucidate the mechanism. The Microphones were set in the out-of-plane direction and the lateral direction of a disc in brake components on a full-sized dynamometer. In the vibration mode in which in-plane stretch vibration was dominant, the sparse and dense parts showed high sound pressure. 3D laser vibrometer was used to check displacements of the disc, and the result indicated a possibility that the sparse and dense parts could vibrate in the out-of-plane direction and generate the sound. Then, complex eigenvalue analysis (CEA) and acoustic simulation were conducted to validate the experimental results.
Technical Paper

Gripper to Defend Bolts in Magnetic Track Brake System

2023-11-05
2023-01-1872
Carbide-tipped gripper dowel secures the bolted joints and plays a significant role in the safety and reliability of the magnetic track brake system. With mainline trains speeds over 250 km/hr the magnetic track brake is automatically activated in case of the emergency brake. As the train passes over switches, crossings, and narrow curves with track distortion, it creates an exceptional lateral and longitudinal force on the bolted joints. The introduction of a gripper between several bolts reduces the shear force of the bolt to a large extent. This solution has the added benefit of facilitating maintenance. The paper presents the application of the gripper in the magnetic track brake and the validation of the gripper using analytical and experimental tests. This study may be applied to a wide range of bolted joints. The experimental results demonstrate the ability of gripper and maximize the durability of the bolt to prevent bolt joint failures.
Technical Paper

IMU Based Velocity Estimation Impact on Stopping Distance for Heavy-Duty Class 8 Truck Air Brake Systems with ABS

2023-11-05
2023-01-1873
An accurate estimate of vehicle speed is essential for optimal anti-lock braking system (ABS) calculations. Currently, most vehicles including heavy-duty class 8 trucks mainly rely on wheel speed sensors (WSS) to estimate velocity. However, as soon as braking is applied, WSS become inaccurate for determining the velocity due to the longitudinal slip developed in the tires. Using the inertial measurement unit (IMU) to estimate vehicle speed allows for its use in conjunction with the WSS to accurately calculate the slip ratio at each tire. These slip ratio values can then be used as the main control variable in the ABS algorithm to utilize the grip available more fully at each tire, to improve stopping distance and controllability. A steady state braking analysis model is developed and validated against Federal Motor Vehicle Safety Standards (FMVSS) 121 60-0 mph stopping distance data for a loaded class 8 tractor semi-trailer combination.
Technical Paper

Characterizing a Real-Driving Brake Emissions Sampling System on a Laboratory Test Bed

2023-11-05
2023-01-1875
Brake wear emissions gained significant relevance with the upcoming Euro7 type approval within the European Union for brake emission measurement on the test bed. While the controlled brake test bed approach provides consistent results, real-driving emission (RDE) measurements are needed to better understand actual emission behavior due to varying vehicle and environmental conditions. The EU has already announced its interest in RDE testing. Here we present the results of an RDE brake wear sampling system with minimal thermal impact, where particles are only sampled from one side of the brake disc, characterized on a laboratory sampling system. The investigations aim to validate symmetric particle release and to confirm that doubling the measured RDE results effectively represents the reference emissions on the test bed.
Technical Paper

Effect of Moisture Adsorption on Low-Speed and Moderate-Speed Braking: Effect on In-Stop Friction Coefficient and Low Frequency Noise

2023-11-05
2023-01-1862
Copper-free NAO disc pads of passenger cars were investigated for a combination of prior braking conditions and moisture adsorption influencing in-stop friction and noise during low-speed stops, and in-stop-friction during moderate-speed stops. Prior braking conditions and moisture adsorption strongly influence subsequent in-stop friction behavior and noise at room temperature. The low-speed in-stop friction behavior looks totally different from that of moderate-speed stops. The low-speed in-stop friction increasingly oscillates with increasing moisture adsorption and goes down towards the end of a stop, which is accompanied by increasing low-frequency noise. The moisture content needs to be quantified/specified to obtain repeatable/reproducible brake test results as the moisture is an unintended and uncontrolled ingredient of a friction material. As the disc surface roughness increases due to prior braking conditions, the friction coefficient of low-speed stops is found to decrease.
Technical Paper

Brake Control Allocation Employing Vehicle Motion Feedback for Four-Wheel-Independent-Drive Vehicle

2023-11-05
2023-01-1866
This paper uses the brake control allocation method for Electric Vehicles (EVs) based on system-level vehicle Reference Point (RP) motion feedback. The RP motion control is an alternative to the standard brake torque allocation methods and results in improved vehicle stability in both longitudinal and lateral directions without requiring additional measurements beyond what is available in EVs with ABS and ESP. The proposed control law simplifies the brake torque allocation algorithm, reduces overall development time and effort, and merges most of the braking systems into one. Additionally, the measured or estimated signals required are reduced compared to the standard approach. The system-level RP measurements and references are transformed into individual wheel coordinate systems, where tracking is ensured by actuating both friction torques and electric motor regenerative torques using a proposed brake torque blending mechanism.
Technical Paper

Brake Pad Moisture Adsorption and Its Effect on Brake Pad Compression Strain/Modulus and Friction Coefficient: Effect of Pad Cure Temperatures

2023-11-05
2023-01-1863
The moisture adsorption kinetics of copper-free brake pads was studied to confirm an earlier finding that the adsorption weight gain follows a logarithmic relationship with respect to the square root of humidity exposure time and the relationship is linear in the beginning. When the pad cure temperature was raised from 120 to 180 and 240 °C, the adsorption rate increased. The 180 °C cure produced the highest pad modulus. With increasing moisture adsorption, the pad compression modulus increased just like the pad dynamic modulus, meaning decreasing compression/compressibility while the ISO ‘compressibility’ determined after 3 compressions under 160 bars increased in contradiction. It is concluded that the ISO ‘compressibility’ is a destructive hardness measurement like the Gogan or Rockwell hardness: the key difference is the indenter covers the entire surface of the pad. The true compressibility must be determined as an inverse function of bulk modulus.
Technical Paper

Electro-Hydraulic Composite Braking Control Optimization for Front-Wheel-Driven Electric Vehicles Equipped with Integrated Electro-Hydraulic Braking System

2023-11-05
2023-01-1864
With the development of brake-by-wire technology, electro-hydraulic composite braking technology came into being. This technology distributes the total braking force demand into motor regenerative braking force and hydraulic braking force, and can achieve a high energy recovery rate. The existing composite braking control belongs to single-channel control, i.e., the four wheel braking pressures are always the same, so the hydraulic braking force distribution relationship of the front and rear wheels does not change. For single-axle-driven electric vehicles, the additional regenerative braking force on the driven wheels will destroy the original braking force distribution relationship, resulting in reduced braking efficiency of the driven wheels, which are much easier to lock under poor road adhesion conditions.
Technical Paper

Brake Squeal – Digital Twinning of a Brake Dynamometer

2023-11-05
2023-01-1884
Brake squeal is a common phenomenon across all types of vehicles. It becomes prominent in the absence of other noise sources, as in the case of electric vehicles. Earlier simulation attempts date back to late nineties and early 2000s. Identification of unstable modes of the coupled system of brake rotor and pads, and occasionally some caliper components, was the primary goal. Simulating the rotation of the rotor along with squeezing of the pads was attempted in a multi-body dynamics tools with flexible representation of rotor and pads. Though this gave some insights into the dynamics of stopping mechanism, squeal required capturing the nonlinearities of the contact in a more rigorous sense. Also, efforts were made to capture noise from vibrations using boundary- and finite- element methods [1].
Technical Paper

Optimization of Brake System Parameters Using Genetic Algorithm

2023-11-05
2023-01-1881
The design of brake system specification is an iterative process, where repeated calculations need to be performed to achieve the target brake performance and finalize the system parameters. Hence there is a need for a methodology to arrive at a set of optimized brake system parameters which can in turn reduce the brake system definition time. In this paper, the brake system dynamics of a passenger/commercial vehicle is mathematically modelled (divided into two parts i) foundation brake model ii) brake apply system model) and uses genetic algorithm to optimize the system parameters. The objective function maximizes the vehicle deceleration and arrives at the target brake feel which includes brake pedal effort and brake pedal travel. When compared to conventional method of brake design which uses iterative approach, this method has the capability to arrive at the optimized results at a faster rate.
Technical Paper

Transfer Learning-Based Neural Network for Natural Frequency Prediction of Linear Dynamic Systems

2023-11-05
2023-01-1883
The prediction of natural frequencies is a crucial aspect of engineering design and analysis. Traditional methods involve finite element analysis (FEA) which is a standard method for calculating natural frequencies of dynamic systems. For each design variant, FEA calculation can be time-consuming and computationally expensive. In this study, we propose a novel method for predicting the natural frequencies of design variants using transfer learning and artificial neural networks (ANN). The proposed method involves the use of FEA to generate the stiffness and mass matrices of the brake disc, which are then used as inputs to the neural network. However, the prediction can become tedious when there is a change in the design. To address this, we employ transfer learning followed by linear regression using a design variant of the previous structure as test data. The neural network learns through transfer learning and fine-tunes its outputs using regression for final frequency prediction.
Technical Paper

Influence of Iron and Manganese on the Mechanical Properties and Microstructure of a Recycled EN AC-43200 Aluminium-Silicon Alloy

2023-11-05
2023-01-1880
The work investigates the effect of different Iron and Manganese contents in ad-hoc cast specimens made from recycled EN AC-43200 alloy. Tensile tests and metallographic analyses coupled with energy dispersive X-ray spectroscopy measurements are carried out to elucidate the interplay between the microstructure and the quasi-static properties of the Aluminium-Silicon alloy under investigation. A strong correlation between the composition and morphology of Fe/Mn -based intermetallic precipitates and tensile properties is demonstrated. Moreover, it is found that specific intermetallic phases are present only for certain, relative and/or absolute contents of Fe and Mn.
X