Pneumatic Braking System Research Articles

The Intelligence Braking and the Pneumatic Automatic Braking System for Autonomous Vehicles

Autonomous driving is the main development direction of the automobile in the present and the future Intelligencebraking is the key assembly to realize autonomous driving The pneumatic brake system is the principle part of commercial vehicle to brake In order to meet the requirements of autonomous driving this paper proposed the concept of intelligent braking and pneumatic automatic braking and then a kind of pneumatic automatic braking circuit is designed The pressure change rate is used as a new index to evaluate automatic braking and control This study provides a new theoretical basis for design and application of the pneumatic braking system

A New Method for Analysing the Pressure Response Delay in a Pneumatic Brake System Caused by the Influence of Transmission Pipes

This study aims to propose an analysis method for resolving the pressure response of a pneumatic brake circuit considering the effect of a transmission pipe. Pneumatic brake systems (PBS) are widely used in commercial vehicles. The pressure response characteristic of the PBS is the key factor affecting braking performance. By using the thermodynamics of a variable-quality system, the pressure response model of the brake chamber is established, which includes the dynamic model of the pipe considering the unsteady friction and heat transfer. The partial-differential control equations of pipe are solved by introducing the constrained interpolation profile (CIP) method, and a virtual chamber model is proposed to set the boundary condition so as to solve the pressure response in the brake chamber simultaneously. Thus, the regularity of the brake pressure response is obtained by considering the influence of the pipe. Lastly, the model is verified experimentally. The present study indicates that the main factors that affect the pressure response delay are the pipe length and the combination forms of the sonic conductances of the orifices inlet and outlet. Furthermore, it helps to verify that the CIP method is an effective way of solving the pressure response of a brake circuit because of its high accuracy. The present study serves as a foundation for the design and analysis of a PBS.

Wheel slip dump valve for railway braking system

As we all know, pneumatic braking system plays an important role in the safety of the whole vehicle. In the anti slip braking system, the pressure of braking cylinder can be adjusted by the quick power response of wheel slip dump valve, so that the lock situation won’t occur during vehicle service. During the braking of railway vehicles, the braking force provided by braking disc reduces vehicle’s speed. But the locking slip will happen due to the oversize of braking force or the reduction of sticking coefficient between wheel and rail. It will cause not only the decline of braking performance but also the increase of braking distance. In the meanwhile, it will scratch the wheel and influence the stable running of vehicles. Now, the speed of passenger vehicle has been increased. In order to shorten the braking distance as far as possible, sticking stickiness must be fully applied. So the occurrence probability of wheel slip is increased.

An Experimental Study on Hysteresis Characteristics of a Pneumatic Braking System for a Multi-Axle Heavy Vehicle in Emergency Braking Situations

This study aims to investigate the hysteresis characteristics of a pneumatic braking system for multi-axle heavy vehicles (MHVs). Hysteresis affects emergency braking performance severely. The fact that MHVs have a large size and complex structure leads to more nonlinear coupling property of the pneumatic braking system compared to normal two-axle vehicles. Thus, theoretical analysis and simulation are not enough when studying hysteresis. In this article, the hysteresis of a pneumatic brake system for an eight-axle vehicle in an emergency braking situation is studied based on a novel test bench. A servo drive device is applied to simulate the driver’s braking intensions normally expressed by opening or moving speed of the brake pedal. With a reasonable arrangement of sensors and the NI LabVIEW platform, both the delay time of eight loops and the response time of each subassembly in a single loop are detected in real time. The outcomes of the experiment show that the delay time of each loop gets longer with the increase of pedal opening, and a quadratic relationship exists between them. Based on this, the pressure transient in the system is fitted to a first-order plus time delay model. Besides, the response time of treadle valve and controlling pipeline accounts for more than 80% of the loop’s total delay time, indicating that these two subassemblies are the main contributors to the hysteresis effect.

The process of gas-dynamic design of pneumatic braking system using the baseline compressor

The article presents the results of work on the design of the air brake for testing of industrial gas turbine engines with free turbine. Designing of the air brake was performed on the basis of existing units using the program CFD - simulation Numeca FineTurbo. During the design the air brake arrangement was determined, which allows to utilize the required power to the shaft of the free turbine, increases stall margin of the air brake by waisting of the meridional flow channel. It was also made designing of the outlet guide vane to remove the residual twist. Unified nozzle also was designed to provide the air brake work at necessary points on the characteristic.

Experimental Investigation on The Electromagnetic Clutch Water pump and Pneumatic Compressor for Improving the Efficiency of an Engine

Considering the fuel crises today many work and research were conducted to reduce the fuel consumption of the internal combustion engine. The fuel consumption of an internal combustion engine can be relatively reduced by use of the electromagnetic clutch water pump and pneumatic compressor. Normally in an engine, the water pump is driven by the crankshaft, with an aid of belt, for the circulation of the water for the cooling process. The circulation of coolant is resisted by the thermostat valve, while the temperature inside the coolant jacket of the engine is below 375K the thermostat is closed only above 375K it tends to open. But water pump run continuously even when thermostat is closed. In pneumatic braking system, pneumatic or air compressor purpose is to compress the air and stored into the storage tank for the brake operation. When the air pressure of the storage tanks gets increases above its storage capacity pressure is regulated by governor, by passing them to atmosphere. Such unnecessary work of this water pump and air compressor can be minimized by use of the electromagnetic clutch water pump and air compressor. The European Driving Cycle is used to evaluate the performance of this water pump and air compressor when used in an engine. The result shows that the fuel economy of the engine while using electromagnetic water pump and pneumatic compressor were improved by 8.0% compared with conventional types which already exist. The application of these electromagnetic water pump and pneumatic compressor are expected to contribute for the improvement of engine performance because of their effect in reduction of the rate of fuel consumption.

Extremum-seeking algorithms for the emergency braking of heavy goods vehicles

A pneumatic slip control braking system was demonstrated, which reduces the emergency stopping distances of heavy goods vehicles by up to 19%. Solutions are still required to set the optimal reference wheel slip for this system online, so that it can adapt to changing operating conditions. This paper considers whether the use of extremum-seeking algorithms is a feasible alternative approach to online tyre model fitting, the computational expense of which has, to date, inhibited real-time implementation. The convergence and the stability properties of a first-order sliding-mode extremum-seeking algorithm are discussed, and its tuneable parameters are recast as physically meaningful performance metrics. Computer simulations are conducted using a detailed braking system model, and hardware-in-the-loop simulations are conducted with prototype pneumatic slip control braking hardware for heavy goods vehicles. The extremum-seeking algorithm enables the braking system to achieve at least 95% of the maximum possible braking force for almost the entirety of an emergency stop. The robustness to parameter errors, the road roughness and the changing friction conditions are all explored.

Efficient coordinated control of regenerative braking with pneumatic anti-lock braking for hybrid electric vehicle

Urban bus has to start and stop frequently due to typical urban traffic conditions, which, however, can be put to good use by regenerative braking. Regenerative braking is a key technology which not only improves vehicle’s fuel economy in mild braking, but also ensures vehicle safety in emergency braking conditions. Because of the inherent limitations of traditional braking system in recycling energy, it is necessary to change its structure to decouple the brake pressure and the brake pedal force. To solve this problem, a compromise design combining traditional pneumatic braking system with brake-by-wire (BBW) system is adopted in this paper on parallel hybrid electric bus. With the transformed braking system, an efficient coordinated control strategy is proposed to solve the problem caused by the different response speeds of pneumatic braking and regenerative braking. The proposed control strategy is carried out, where the road condition varies and different control methods are adopted. Results show that the adopted braking system and the proposed coordinated control strategy are suitable for different roads, and effective in recovering energy and ensuring vehicle safety. At the same time, shorter braking distance and better control of slip ratio verify the performance of MPC compared with a logical threshold-based control. Therefore, this study may offer a useful theoretical reference to the choice of braking system and braking control strategy design in hybrid electric vehicle (HEV).

Dynamic coordinated control of a downhill safety assistance system for hybrid electric buses

When driving downhill, downhill safety assistance control can ensure a safe speed. A downhill safety assistance system was developed by our research group to help hybrid electric vehicles to maintain a stable speed when driving downhill. For hybrid electric buses, in addition to the pneumatic braking system, the motor can quickly provide an electrical braking torque, and the engine can be considered a mechanical brake. The downhill safety assistance system for hybrid electric buses maintains the desired downhill speed on different road slopes. However, when and how to activate or deactivate the downhill safety assistance system because of the driver’s operation or the road conditions was not discussed in combination with the energy management strategy for the vehicle. Additionally, there is currently no dynamic control strategy for the transition process when the braking modes of the downhill safety assistance system change, which can lead to instability. To address the limitations of previous studies, a dynamic coordinated control strategy of the downhill safety assistance system is proposed considering practical application, which focuses on the above two aspects to keep the entire system stable. To improve the ride comfort and the vehicle safety when the downhill safety assistance system works in conjunction with the energy management strategy for the vehicle, the proposed control strategy is developed to activate or deactivate the downhill safety assistance system based on the driver’s driving habits and operation and the road conditions in order to reduce the workload and to improve the driveability of the buses. To maintain the ride comfort during the transient process of shift in the braking mode and to maintain a stable speed over the overall course, the mode-shift coordinated control strategy of the downhill safety assistance system is presented, which combines the braking modes to ensure that the braking torque changes steadily without saltation. The experimental results validate the performance of the entire dynamic coordinated control strategy of the downhill safety assistance system with a high stability, and the statistics demonstrate that the downhill safety assistance system obviously improves the fuel economy and reduces the driver workload.

Automatic Disc Braking System Experimental Investigation

The main objective of this project is for security system. If vehicle moves very near to the opposite vehicle then it applies brake automatically. It is used for avoiding accident over by racing in highways and parking or busy traffic areas through pneumatic braking. Pneumatic braking system works faster when compared to other devices. So we can achieve the high efficient operation by programming the microcontroller. The disc brake is a device for slowing or stopping the rotation of a wheel. Friction causes the disc and attached wheel to slow or stop. Brakes convert friction to heat, but if the brakes get too hot, they will cease to work because they cannot dissipate enough heat. This condition of failure is known as brake fade. Disc brakes are exposed to large thermal stresses during routine braking and extraordinary thermal stresses during hard braking.

Design and Analysis of a Glass Fibre Trolley

This project is based on design and analysis of a glass fibre trolley, for carrying engineering components, other materials at an engine manufacturing plant. Currently AISI 1020 mild steel trolleys are used for moving the goods around the stores or assembly area. These are simple in design but hefty, with four rollers but no braking mechanism. Use of glass fiber as a trolley material is advisable. Stress analysis has been performed for a typical load. This project will ensure weight reduction as well as an improved design, that makes use of electro pneumatic braking system.

Hardware-in-the-Loop Pneumatic Braking System for Heavy Truck Testing of Advanced Electronic Safety Interventions

The rapid innovation underway with vehicle brake safety systems leads to extensive evaluation and testing by system developers and regulatory agencies. The ability to evaluate complex heavy truck braking systems is potentially more rapid and economical through hardware-in-the-loop (HiL) simulation which employs the actual electronics and vehicle hardware. Though the initial HiL system development is time consuming and expensive, tests conducted on the completed system do not require track time, fuel, vehicle maintenance, or technician labor for driving or truck configuration changes. Truck and trailer configuration and loading as well as test scenarios can be rapidly adjusted within the vehicle dynamics simulation software to evaluate the performance of automated safety interventions (such as ESC) over a wide range of conditions. Hardware-in-the-loop simulation does not obviate the need for all track testing; vehicle models for simulation must be validated against track data for each truck platform. But HiL simulation can supplement and extend track data for tests at higher speeds, low friction surfaces, and alternate vehicle configurations. A HiL pneumatic braking system was developed for this purpose by the National Highway Traffic Safety Administration, with the goal of evaluating performance as it relates to safety. This paper describes the system in detail and includes some sample results of the testing. Language: en

Model predictive control-based efficient energy recovery control strategy for regenerative braking system of hybrid electric bus

As one of the main working modes, the energy recovered with regenerative braking system provides an effective approach so as to greatly improve fuel economy of hybrid electric bus. However, it is still a challenging issue to ensure braking stability while maximizing braking energy recovery. To solve this problem, an efficient energy recovery control strategy is proposed based on the modified nonlinear model predictive control method. Firstly, combined with the characteristics of the compound braking process of single-shaft parallel hybrid electric bus, a 7 degrees of freedom model of the vehicle longitudinal dynamics is built. Secondly, considering nonlinear characteristic of the vehicle model and the efficiency of regenerative braking system, the particle swarm optimization algorithm within the modified nonlinear model predictive control is adopted to optimize the torque distribution between regenerative braking system and pneumatic braking system at the wheels. So as to reduce the computational time of modified nonlinear model predictive control, a nearest point method is employed during the braking process. Finally, the simulation and hardware-in-loop test are carried out on road conditions with different tire–road adhesion coefficients, and the proposed control strategy is verified by comparing it with the conventional control method employed in the baseline vehicle controller. The simulation and hardware-in-loop test results show that the proposed strategy can ensure vehicle safety during emergency braking situation and improve the recovery energy almost 17% compared with the conventional rule-based strategy in the general braking situation. Therefore, the proposed control strategy might offer a theoretical reference for the design of the actual braking controller in engineering practice.

Full-scale testing of a novel slip control braking system for heavy vehicles

This paper summarises the measured emergency braking performance of a tri-axle heavy goods vehicle semitrailer fitted with a novel pneumatic slip control braking system developed by the Cambridge Vehicle Dynamics Consortium. Straight-line braking tests were carried out from 40 km/h in order to compare a commercially electro-pneumatic available anti-lock braking system and the Cambridge Vehicle Dynamics Consortium system, which has bi-stable valves coupled with a sliding-mode slip controller. On average, the Cambridge Vehicle Dynamics Consortium system reduced the stopping distance and the air use by 15% and 22% respectively compared with those for the conventional anti-lock braking system. The most significant improvements were seen on a wet basalt-tile surface (with similar friction properties to ice) where the stopping distance and the air use were improved by 17% and 30% respectively. A third performance metric, namely the mean absolute slip error, is introduced to quantify the ability of each braking system to track a wheel slip demand. Using this metric, the bi-stable valve system is shown to improve the wheel slip demand tracking by 62% compared with that of the conventional anti-lock braking system. This improvement potentially allows more accurate control of the wheel forces during extreme manoeuvres, providing scope for the future development of advanced stability control systems.

Simulation of the braking system of car under the control of ABS in MATLAB SIMULINK

It is developed a mathematical model of the braking system of a car equipped with ABS by means of MATLAB SIMULINK. The results, which allow visually explore the basic physical processes associated with the exploration and development of existing and new control algorithms of ABS, are received. The article deals with a pneumatic braking system under the control of ABS, which is most common and installed on buses and trucks. Its modeling is performed on a graphical interface of MATLAB SIMULINK, and is essentially a means of visual programming.This work allows us to estimate the correct approach to the study of the dynamic and technical parameters of the ABS and achieve clarity of the processes occurring during operation of the ABS.The study found that this model in the first approximation can be used as the primary outcome correct approach to mathematical modeling of the ABS.The obtained results are important for the further improvement of the primary model, namely, accounting for additional factors that affect the correct operation of the brakes of the car (road condition, accuracy of the sensors, dynamics of the car traffic, wheel drift during turn, etc.).

Dynamic Modeling and Experimental Verification of Bus Pneumatic Brake System

The dynamic characteristic of pneumatic brake system is very important, so the full-parameter model of the pneumatic brake system was established on the base of the technology of computer simulation. Its key brake components include brake valve, relay valve, diaphragm brake chamber and pneumatic circuit. AMESim was first introduced on the basis of mathematical derivation. So the multivariable complexity derivation, nonlinear mathematical relationship can be avoided. The model can be used for the bus brake system multi-parameter simulation and design. A pneumatic brake system test-bed was designed to verify the accuracy of the model. It can measure the dynamic characteristic and the output response coordination of each component. It was showed that the simulation results were fit to the experiment results. For the deviation, the explanation and analysis were also given. The response hysteresis of the brake system is mainly caused by the rubber diaphragm deformation in brake chamber. This research laid the foundation for the further structural optimization of brake components and fitness analysis of the pneumatic brake system.

Modeling, Experimentation and Sensitivity Analysis of a Pneumatic Brake System in Commercial Vehicles

Modeling, Experimentation and Sensitivity Analysis of a Pneumatic Brake System in Commercial Vehicles

Optimal Operation of Heavy-Haul Trains Equipped With Electronically Controlled Pneumatic Brake Systems Using Model Predictive Control Methodology

An optimal control methodology for heavy-haul trains with the objective to optimize the train's operation in terms of energy consumption, velocity tracking, and operation safety is introduced. Rather than optimize the operation of the train at a specific position, this approach tries to schedule the train during a long period of travel in a model predictive control (MPC) framework; therefore, an effort is made so that the operation strategy of the train is optimal during a track section rather than at a specific position, as is done in existing literature. With this purpose, the cascade mass point model of the train is first simplified and transformed to facilitate the controller design. Then, an optimal controller is presented taking advantage of the MPC concept with the future behavior of the train and all operational constraints considered. Simulations demonstrate the feasibility as well as the advantages of the proposed approach.

Braking energy regeneration control of a fuel cell hybrid electric bus

This paper presents the braking energy regeneration control of a fuel cell hybrid electric bus. The configuration of the regenerative braking system based on a pneumatic braking system was proposed. To recapture the braking energy and improve the fuel economy, a control strategy coordinating the regenerative brake and the pneumatic brake was designed and applied in the FCHB. Brake safety was also guaranteed by the control strategy when the bus encounters critical driving situations. Fuel economy tests were carried out under China city bus typical driving cycle. And hardware-in-the-loop tests of the brake safety of the FCHB under proposed control strategy were also accomplished. Test results indicate that the present approach provides an improvement in fuel economy of the fuel cell hybrid electric bus and guarantees the brake safety in the meantime.

Research on Simulation of Electronic-Controlled Pneumatic Regenerative Braking System

In order to improve braking stability and energy recovery ability of electric buses, a new-type electronic-controlled pneumatic regenerative braking system for electric buses was designed. The regenerative braking system controls pneumatic braking force of front and rear wheels by high-speed solenoid valves, which could coordinate mechanical and regenerative braking force effectively. A simulation model of electric bus braking process was established, as well as regenerative braking control strategy. Simulink and AMESim joint simulation analysis of braking process of electric bus was run. The results show that energy recovery of the new-type regenerative braking system is effective and braking control strategy is reasonable.