Browse Topic: Air brakes
Brake failures in the vehicles can cause hazardous accidents so having a better monitoring and emergency braking system is very important. So, this project consists of an autonomous brake failure detector integrated with Automatic Braking using Electromagnetic coil braking which detects the braking failure at the time and applied the combinations of the brakes, to overcome this kind of accidents. So, here the system comprises of IR sensor circuit, control unit and electromagnetic braking system. How it works: The IR sensor monitors the brake wire, and if the wire is broken, the control unit activates the electromagnetic brakes, stopping the vehicle in a safe manner. This system enhances vehicle safety by ensuring immediate braking action without driver intervention. Key advantages include real-time brake monitoring, reduced mechanical wear, quick response time, and an automatic failsafe mechanism. The system’s minimal reliance on hydraulic components also makes it suitable for harsh or variable conditions. The proposed system can be widely implemented in automobiles, especially those using drum brakes, as well as railway systems to prevent accidents due to brake failure. Future advancements in predictive maintenance, machine learning, and AI integration could further improve the reliability, adaptability, and overall efficiency of this advanced braking system.
This SAE Standard is intended to establish uniform performance criteria and methods of testing push-to-connect tube fittings, with SAE J844 air brake tubing as used in vehicular air brake systems. The specific tests and performance criteria applicable to the tubing are set forth in SAE J844. The test values contained in this performance standard are for test purposes only. For environmental and usage limitations, refer to SAE J844.
This SAE Standard covers complete general and dimensional data for the manufacture of, T6061-T6 Aluminum cavities designed to receive Push To Connect threadless fittings known as “cartridges“, for air brake applications. This document is not intended to specify or recommend any style or manufacture of such cartridges but to establish uniform cavity dimensions for interchangeability purposes.
In an air brake system, compressed air is used as an energy medium for braking applications, ensuring a good seal between the components is critical. The sealing performance of gaskets are significant for the product with joint features as it affects functionality and can cause a breakdown of the entire system; hence, finite element simulation of the sealing performance of gaskets is important for any product development. To simulate fluid interacting with gasket, a fluid-structure interaction (FSI) simulation is necessary by co-simulating a computation fluid dynamics (CFD) and finite element analysis (FEA) solvers to capture complex behavior of seal deformation under dynamic conditions during leakage, but it is a time-consuming process. In this article, the sealing performance of gaskets is studied in detail only till the start of leakage. It is not necessary to simulate the dynamic behavior of the seal beyond leakage to validate the sealing performance; hence, static nonlinear analysis is performed in FEA to capture the seal behavior. But instead of simulating the interaction of fluid as a normal pressure load, a new technique called pressure penetration load is applied. This new technique can not only simulate the normal pressure on the seal and body but also simulate the penetration of fluid through the seal. The intensity of penetration depends on the contact pressure and exists at the interface between the seal and body, due to bolt torque. If the contact pressure is less, the fluid pressure can penetrate and open the contact. This method can predict the possibility of leakage efficiently, and the computation cost is less compared to FSI simulations involving two solvers. The contact pressure developed during the assembly process is simulated and confirmed with the Fuji film test—a pressure-indicating sensor film. Using pressure penetration load, the sealing performance is analyzed to ensure no leakage during extreme conditions. With this methodology, the gasket groove volume, number of bolts, bolt torque, and bolt locations can be optimized. This paper also discusses the sensitivity of various FEA parameters like element size, element type, and dependence of bolt modelling for the current simulation to reduce computation time. This methodology can be applied to validate various products with face-sealing gaskets. A design optimization study is done using this method to convert a metal cover into plastic material with topology optimization to save weight and overall cost of the product.
This Recommended Practice provides a road test procedure for trucks and buses, to evaluate their compliance with Federal Motor Vehicle Safety Standard (FMVSS) 121; Air Brake Systems. Units of measure are English in lieu of metric to be consistent with FMVSS 121.
This SAE Recommended Practice provides a road test procedure for truck-tractors, to evaluate their compliance with Federal Motor Vehicle Safety Standard (FMVSS) 121. Units of measure are English in lieu of metric to be consistent with FMVSS 121.
This SAE Recommended Practice is intended for qualification testing for brake drums used on highway commercial vehicles with air brakes using an inertia-dynamometer procedure. This document consists of two distinct tests: Part A, durability and speed maintenance test, and Part B, heat check drag sequence test. Each test can be considered to be an independent evaluation of the brake drum which tests different properties.
This SAE Recommended Practice is intended for measuring the static brake torque performance of a pnuematically actuated brake assembly, friction material, and drum/disc combination on an inertia brake dynamometer.
This SAE Information Report lists common port connection types used in truck, bus, truck-trailer, converter dolly, and multi-purpose vehicles with air brake systems at the time of publication. The purpose of the document is to give system designers and users a starting point for connector selection and a reference to the standards that govern these connector types. Also included are notes on common practices associated with these ports. CAUTION: Consult the relevant standard for the connector before making a decision on suitability for use in a specific application.
This SAE Recommended Practice applies to S-CAM, wedge, and disc air brake actuators where the stroke can be measured without disassembly from the brake.
The braking capacity of reducing the speed or even keeping the vehicle stoped is extremely important in the design of any brake system, as more than meeting legislation requirements; it directly affects the safe operation of the vehicle and its users. A fundamental component, which requires notable attention, is the friction material, which is designed to establish a compromise between mechanical properties, friction coefficient, noise propensity, deformation, wear, among others. However, braking capacity is a combined response for several of these friction material properties, along with the performance of other brake system components, such as the brake chamber, disc and caliper. This work aims to analyze firstly the influence of the friction material deformation and secondly the brake system deformation on the total stroke of the brake chamber. To the first one, three different formulations of friction material, applied to commercial vehicles, were selected. For these materials, compressibility measurements were performed, according to ISO 6310, and also subjected to static test for measuring the total stroke of the brake chamber, in an inertial dynamometer. The static test performed consists of a pressure ramp application on the brake pad with the measurement of the total chamber stroke for each of the pressures. To the second one, static test was performed using steel pads (copying the brake pad shape), with thickness simulating new and end-of-life pads. The friction material and the brake system showed a significant pressure sensitivity, with a small contribution at low pressures, increasing its contribution with pressure increase. More than it, this work allowed to understand that the formulation, pad compressibility, material thickness, brake system stiffness, temperature and chamfered pads show a significant influence on the performance, fuel consumption and reduction of pollutants), there are also improvements to be made on braking performance and reduction of early wear. These improvements must also be applied to commercial vehicles such as trucks and buses, where the brake system is subjected to heavy loads and long routes. For this type of vehicle is very important to obtain maximum brake pad durability, in order to reach customer satisfaction. For commercial vehicles, the use of disc brakes has been increasing gradually, once it is already widely applied in Europe and there is a gradual growth in North American and Asian markets. Brazil tends to follow the same path as Europe, only slower, due to drum brakes costs, which are much lower than disc brake costs. Disc brake system has greater advantages compared to the drum brake system, such as: higher braking efficiency, even on higher application temperatures; greater dissipative energy capacity during braking and, finally, greater comfort during brake pedal actuation [2]. Pedal force and displacement are important factors for the driver to modulate, regarding safety and braking efficiency. It shows that soft pedal feeling is not only unsafe due to lack of vehicle control and accidental brake lock, but can also generate longer stopping distances [3]. Technically, the term known as Pedal Sensitivity means the relationship between the force applied to the pedal, the pedal travel and the deceleration achieved by the vehicle. Normally, the vehicle's brake capacity is evaluated on a field test, considering different conditions of deceleration, force and chamber stroke.
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. As with all systems on an electric-semi truck the benefits must be delivered with the best-in-class total cost of ownership to ensure fleet customers’ switching costs are low and their investment has a rapid payback. Reciprocating compressors traditionally used in this market are not optimized for these new requirements. Alternative compressor technologies will be adopted, such as rotary screw, scroll, rotary vane, or possibly other technologies may replace piston compressor technology completely as part of the electrification of semi-trucks. Successful compressors in the electric-semi market can be expected to deliver solutions to the electric bus markets too if they have the capability of being highly reliable at very high duty cycles. Each of the compressor technologies weak points must be addressed to the extent possible and must be designed specifically for the application by the technology specialists in order to compete in this market. “The Company” has 35 years’ experience developing, manufacturing, and supporting their rotary screw technology on mobile platforms globally. “The Company” has taken on the challenge of developing an EV screw compressor solution for the electric-semi and bus application. Based upon potential commercial electric-semi manufacturer demands the author analyzes the inherent advantages and disadvantages of different compressor technologies, their working boundary conditions and creates the basic technology specifications to meet the air deliver rate and discharge pressure requirements. Screw compressor technology has a reputation of high reliability, high energy efficiency and it is suited for extreme climatic conditions. It will be one potential candidate for electric-semi air brake systems. The primary design output requirements are considered to be 354 LPM (liter per minutes) or 12.5 CFM (cube feet per minutes) with discharge pressure range 1.02~1.36 MPa or 150~200 PSI. This broad air and pressure range is possible due to the characteristic of the screw compressor air deliver/RPM curve being flat. This paper describes the unique approach “THE COMPANY” has taken to optimize rotary screw compressor technology to deliver the performance required by electric-semi’s and electric buses. This development introduces a single stage rotary screw technology into the mini-compressor world for a high air pressure application. The product is currently being prepared for low - medium volume production with high volume production potential in 2022. The performance and unique technology features as they pertain to the electric-semi market are described in this paper. “THE COMPANY” has verified that dramatically decreasing the size of the rotary screw technology addresses the high efficiency, size, mass, space claim, and reliability for this new application.
This article describes the development of a low-cost rotary screw compressor technology to meet the requirements of a mini air compressor application for electric vehicle (EV) air brake and suspension systems. An existing rotor profile and size was initially used to build an “Alpha” compressor prototype. This was tested to provide data for analysis and numerical simulation to determine a smaller rotor size, rotor profile, and more efficient overall package for hybrid/EV air brake and suspension applications. From the “Alpha” prototype testing and analysis, the author identified the root causes of lower energy efficiency. To address these deficiencies and develop a foundation for an optimized solution for the intended application, the author developed a clean sheet design. A smaller diameter rotor set with high tip speed was developed using parameter calculations, working process simulation, and prototype test data analysis. By incorporating an innovative J-profile rotor screw lobe design, “VMAC” created a set of small rotary screw rotors that are optimized for a reduced air delivery rate, high-pressure ratio, and compact size while achieving a high energy efficiency target. Through testing, the compressor has proven to significantly save energy compared with the other compressor technologies. Endurance testing results prove that the developed compressor maintains the high-reliability advantage of the screw compressor technology. The compressor development has utility in electric buses and electric trucks due to its high-pressure capability that supplies high energy density to allow for smaller pressurized air tanks and a boost mode for rapid air recharge.
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