scholarly journals Assessment of the functional functionality of passenger car brake systems by changing the braking distance during operation

2021 ◽  
Vol 13 (1) ◽  
pp. 78-86
Author(s):  
Alexander Nazarov ◽  
◽  
Vitalii Kashkanov ◽  
Ivan Nazarov ◽  
Yevhen Ivanchenko ◽  
...  
Keyword(s):  
Operating Conditions ◽  
Passenger Cars ◽  
Passenger Car ◽  
Emergency Braking ◽  
Braking System ◽  
Braking Distance ◽  
Braking Force ◽  
Braking Process ◽  
Relative Change

The article discusses a methodology for assessing the functional suitability of brake systems to change the braking path of passenger cars, taking into account various operating conditions. The goal is achieved by using the method of mathematical modeling of the emergency braking process, taking into account the possible operating conditions of cars performing emergency braking at certain initial speeds, in particular, exceeding 100 km / h. Based on the analysis of scientific sources, it has been established that the determination of the braking efficiency of a vehicle classically occurs on the verge of blocking all wheels with known methods of distributing braking forces between the axles of the vehicle. In this case, the standards set the maximum value of the minimum deceleration and braking distance. In addition, the jump in the maximum possible value of the braking force between the wheels of each axle makes it possible to compare it with the requirements of DSTU 3649: 2010, and the assessment of the magnitude of this jump for each braking of the car is to establish its functional suitability. As a result, according to the magnitude of the jump in the maximum possible value of the braking distance, the change in the maximum allowable braking force of the car sets, and according to the magnitude of its jump, it is possible to assess the functional suitability of its braking system. As a result, the use of expert information on the value of jumps in the maximum possible value of the braking force of a car, affecting the braking torques and braking coefficient, can reduce the amount of experimental research and significantly reduce the time to reach an objective decision on the functional suitability of the brake systems of operated cars. The paper presents the results of theoretical studies of passenger cars Chevrolet Aveo, Lada Priora and Forza with different loads, performing emergency braking at an initial speed of 40-150 km / h on a road with dry asphalt concrete. The boundaries of the coefficient of the relative change in the braking distance of the tested passenger car, at which it is possible to make a conclusion about the functional suitability of its braking system, have been established.

scholarly journals Comparative assessment of braking properties of operated passenger cars, according to brake wear

2021 ◽  
Vol 12 (2) ◽  
pp. 76-84
Author(s):  
Alexander Nazarov ◽  
◽  
Ivan Nazarov ◽  
Yevhen Shpinda ◽  
Sergiy Shablenko ◽  
...  
Keyword(s):  
Comparative Assessment ◽  
Operating Conditions ◽  
Passenger Cars ◽  
Passenger Car ◽  
Adhesion Properties ◽  
The Road ◽  
Braking System ◽  
Brake Force ◽  
Output Characteristics ◽  
Braking Process

The article proposes a method for assessing the change in the braking properties of passenger cars during operation following a change in the main characteristic of the brake system - the coefficient of distribution of braking forces between the axles of vehicles, both equipped and not equipped with tracking systems for the braking process by installing brake force regulators in the brake circuits, working according to different laws of changing the drive pressure. The aim of the work is a comparative assessment of the braking efficiency of passenger cars using the example of Lanos cars, the braking systems of which are equipped with various devices for changing the coefficient of distribution of braking forces between the axles, under changing operating conditions. It is known that braking efficiency is an indicator characterizing the braking properties and the ability of a car to maintain a given law of motion during braking, which is determined both by the nature of the adhesion properties of the wheels to the road and the capabilities of the braking system itself to implement these properties. Since the operating conditions of passenger cars significantly affect the braking properties, in order to ensure the required braking efficiency, it is necessary to take into account the change in the primary distribution coefficient of the braking forces generated by the braking mechanisms and the change in their implementation during the operation period. In order to assess the change in the braking properties in the general case of the operation of a passenger car, the dependence of the actual coefficient of distribution of braking forces between the axles on the braking coefficient was proposed. Moreover, the value of the coefficient of distribution of braking forces between the axles depends both on the type of laws of regulation of braking forces and on the residual values of the parameters of braking systems that determine these laws. These dependences on the parameters of the braking systems and the parameters of the passenger car in operation are a function of the goal for determining the residual output characteristics of its braking system.

scholarly journals Simulation Study of the Process of Friction in the Working Elements of a Car Braking System at Different Degrees of Wear

2018 ◽  
Vol 12 (3) ◽  
pp. 221-226 ◽  
Author(s):  
Andrzej Borawski
Keyword(s):  
Simulation Study ◽  
Friction Pair ◽  
Experimental Studies ◽  
Real Life ◽  
Operating Conditions ◽  
Heating Process ◽  
Passenger Cars ◽  
The Road ◽  
Emergency Braking ◽  
Braking System

Abstract Among the many elements of a modern vehicle, the braking system is definitely among the most important ones. Health, and, frequently, life, may rest upon the design and reliability of brakes. The most common friction pair used in passenger cars today is a disc which rotates with the road wheel and a cooperating pair of brake pads. The composite material of the pad results in changing tribological properties as the pad wears, which was demonstrated in experimental studies. The change is also facilitated by the harsh operating conditions of brakes (high and rapid temperature changes, water, etc.). This paper looks into how changing tribology reflects on the heating process of disc and pads during braking. And so a simulation study was conducted, as this method makes it possible to measure temperature in any given point and at any time, which is either impossible or extremely difficult in real life conditions. Finite element method analyses were performed for emergency braking events at various initial speeds of the vehicle reflecting the current road speed limits.

Influence of Shock-Absorber Parameters on Vehicle Vibrations during Braking

2006 ◽  
Vol 113 ◽  
pp. 235-240 ◽  
Author(s):  
Robertas Pečeliūnas ◽  
Olegas Prentkovskis
Keyword(s):  
Mathematical Model ◽  
Shock Absorber ◽  
Research Results ◽  
Vehicle Suspensions ◽  
Emergency Braking ◽  
Vibration Theory ◽  
Braking Distance ◽  
Braking Process ◽  
Vehicle Movement

The main goals of the work are to define consistent patterns of impacts exercised by vibration of the vehicle in emergency braking on the vehicle’s movement mode and on the braking distance and to analyze the formation of oscillation. Besides, it is aimed to extend expert’s opportunities for modeling vehicle movement for investigation of accidents’ circumstances related to vehicle braking with the aid of the developed models. A mathematical model of impact exercised by bumper’s characteristics on the vehicle’s braking process has been designed, enabling the determination of coefficients of longitudinal relative forces of the vehicle’s front and rear axles, which depend on the road’s pavement and its condition. The obtained research results extend the vehicle vibration theory in transitional movement modes, which are used in the design and improvement of vehicle suspensions, as well as in traffic accident’s investigation and improvement of methodology of their expertise calculations.

scholarly journals Parameters of the car's brakes work in real operation condition

2018 ◽  
Vol 19 (12) ◽  
pp. 500-507
Author(s):  
Jerzy Kupiec ◽  
Zbigniew Pikosz ◽  
Grzegorz Ślaski
Keyword(s):  
Operating Conditions ◽  
Measuring System ◽  
Vehicle Speed ◽  
Operation Condition ◽  
Temperature Changes ◽  
Emergency Braking ◽  
Braking System ◽  
Brake Discs ◽  
Braking Process ◽  
Typical Temperature

The article presents the results of measurements and statistical analysis of the variables characterizing the braking process and the work of the car's braking system in diversified operating conditions. The introductory part presents a measuring system that allows measurements of brake system operation parameters during operation. Discussed are the methodology for measuring and determining such values as the temperature of the discs, unit pressures and the slip speed at the contact of the disc and brake pad, braking pressure, vehicle speed and its longitudinal acceleration. Operational working conditions included urban driving, extra-urban and motorway driving. Based on the measurements made, histograms of measured values were developed. On the basis of the obtained results, typical temperature gains during a single braking in individual conditions were determined and the course of temperature changes during cooling of the brake discs was analyzed. The ranges of typical values of the tested parameters for individual operating conditions were generalized and compared with the values characteristic for emergency braking, which can be considered as maximum values.

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

2017 ◽  
Vol 231 (14) ◽  
pp. 1961-1977 ◽  
Author(s):  
Graeme Morrison ◽  
David Cebon
Keyword(s):  
Performance Metrics ◽  
Sliding Mode ◽  
Model Fitting ◽  
Operating Conditions ◽  
Extremum Seeking ◽  
Wheel Slip ◽  
Slip Control ◽  
Emergency Braking ◽  
Braking System ◽  
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.

Real-Time Detection of Unsealed Surfaces During Skidding

2003 ◽  
Vol 1819 (1) ◽  
pp. 237-243
Author(s):  
Kerry J. McManus ◽  
Aaron S. Blicblau ◽  
Christopher J. Broadhurst ◽  
Ashley M. S. Carter
Keyword(s):  
Significant Degree ◽  
Emergency Braking ◽  
Emergency Situations ◽  
Passenger Vehicles ◽  
Braking System ◽  
Antilock Braking System ◽  
Road Surfaces ◽  
Timely Response ◽  
Braking Distance ◽  
Abs Algorithm

The antilock braking system (ABS) fitted to modern passenger vehicles is intended to provide reliable and efficient braking under critical road conditions or in emergency situations. Thus, ABS-equipped vehicles should remain steerable and maintain directional stability in the event of emergency braking. The ABS on vehicles operates on the principle of detection of brake lockup and release of the lockup to prevent an uncontrollable skid developing on sealed roads. However, on gravel roads or snow-covered roads braking distances can be reduced if brake lockup occurs and a wedge of gravel or snow is allowed to form in front of the wheels. The intervention of ABS prevents the wedge from forming to any significant degree, thereby extending the braking distance. An investigation was carried out of a method of discriminating between sealed and unsealed road surfaces in which a signal can be developed so that an alternative ABS algorithm can be applied specifically for gravel-covered surfaces. An attempt was made to identify and measure the buildup of gravel in front of the wheel directly, using an infrared distance-measurement sensor. Initial tests have shown that the system can provide a signal to the ABS, which will allow a timely response to enable intervention in the activation of the algorithms in the ABS.

scholarly journals Testing the Impact of Braking Algorithm Parameters on Acceleration and Braking Distance for a Suspended Monorail with Regard to Acceptable Travel Speed in Hard Coal Mines

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7275
Author(s):  
Jerzy Świder ◽  
Kamil Szewerda ◽  
Krzysztof Herbuś ◽  
Jerzy Jura
Keyword(s):  
Numerical Simulations ◽  
Coal Mines ◽  
Travel Speed ◽  
Hard Coal ◽  
Speed Limit ◽  
Emergency Braking ◽  
Increased Risk ◽  
Braking Distance ◽  
Braking Force ◽  
The Impact

Increasing the maximum speed limit of suspended monorails, which became a very popular means of auxiliary transport, is one of the aspects of improving the efficiency of work in underground coal mines. It is especially important to enable higher (than allowed by the law) travel speed, when moving the crew to and from the workplace, which is often very distant from the shaft, and can take more than one hour of travel. Increasing this speed will make it possible to extend the effective working time of miners, which should have a positive impact on the economics of the mine. However, driving at a higher speed is also associated with increased risk of a negative impact of dynamic overload to people, e.g., during emergency braking of the suspended monorail. The concept of sequential emergency braking was developed in order to avoid excessive deceleration affecting passengers and the operator of the monorail, as well as to minimize the dynamic loads acting on the rail suspensions and on the roadway support frames, which could cause serious accidents. The developed assumptions with regard to the new method of braking are innovative in the area related to hard coal mining, where there are currently no such solutions. According to the principles of the developed concept, the total braking force was divided into two stages. The activation of the second stage depends on the deceleration measured after the time delay from activation of the first stage of braking. We present the results of the numerical simulations, which aimed to analyze the impact of changing the parameters of the braking algorithm on the braking deceleration, the braking time, and the braking distance. The possibility of changing the braking force and downward emergency braking on a high inclination angle were also taken into account during the numerical simulations. Use of the developed emergency braking algorithm enables the optimization of this process at a higher speed than is currently used. This aspect is also very important in increasing the safety for people travelling at a higher speed limit. The numerical simulations provide knowledge for safety in terms of the dynamic overload during emergency braking, without injury risk to miners or damage to equipment.

Substantiation of the influence of changes in the coefficient of axle distribution of braking force on the handling of a passenger car

2022 ◽  
Vol 14 (2) ◽  
pp. 72-79
Author(s):  
Alexander Nazarov ◽  
◽  
Vitalii Kashkanov ◽  
Roman Gumenyuk ◽  
Evgenui Kotik ◽  
...  
Keyword(s):  
Center Of Mass ◽  
Longitudinal Axis ◽  
Physical Characteristics ◽  
Steering Wheel ◽  
Braking System ◽  
Braking Force ◽  
Instantaneous Center ◽  
Braking Process ◽  
Electronic Tracking ◽  
New Algorithms

The article considers the change of the radius of the instantaneous center of rotation of a car moving along a curved trajectory during braking, taking into account the lateral input of the wheels of both axles of cars, both equipped with electronic tracking systems and not equipped with such. A criterion for assessing the controllability of cars moving on a curved trajectory in a braked state, by comparing the ratio of the current speed of the car to the longitudinal base with the ratio of the coefficients of lateral tire input to the product of the longitudinal base of the car, mass and cosines. It is established that the radius of instantaneous rotation of the longitudinal axis of the car moving along a curved trajectory during braking depends on the speed of the center of mass of the car, the coefficient of axle distribution of braking force, physical characteristics of applied tires, steering wheel angle and design and weight parameters. As a result, it allows you to set controllability. The authors obtained dependences that will create new algorithms for the operation of modern electronic control systems for stabilizing the longitudinal axis of a braked car, taking into account the speed of the car, its design and weight characteristics, the main characteristics of its braking system (coefficient of axle braking force distribution), physical characteristics used tires on wheels and connect them to the angles of the steered wheels, controlling the deviation of the longitudinal axis, which allows the driver to maintain the possibility of quite sharp maneuvers directly in the braking process, moving along a curved trajectory.

Application of microwave Doppler displacement sensors in anti-lock braking system

2021 ◽  
pp. 43-48
Author(s):  
Dmitry V. Khablov
Keyword(s):  
Distribution System ◽  
Wheel Speed ◽  
Road Surface ◽  
The Road ◽  
Braking System ◽  
Speed Sensor ◽  
Displacement Sensors ◽  
Braking Distance ◽  
Braking Force

The issues of optimization of the vehicle anti-lock braking system are considered. To increase the reliability of the system, it is proposed to use a brake distribution system adaptive to the quality of the road surface for a quick stop of the vehicle while maintaining controllability. The system together with sensors angular wheel speed included a microwave Doppler displacement and speed sensor. The use of the specified Doppler sensor made it possible to achieve a more accurate coincidence of the dependence of the braking force on the degree of adhesion of the wheels to the road surface by monitoring the ratio between the angular and linear speeds of movement. In this way, it was possible to minimize the braking distance of the vehicle while maintaining controllability under various driving conditions.

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