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 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 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.

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.

TESTING BRAKE FLUID WEAR PROCESSES IN COMPLEX CONSTRAINED CONDITIONS

Tribologia ◽  
2017 ◽  
Vol 273 (3) ◽  
pp. 21-27
Author(s):  
Henryk BĄKOWSKI ◽  
Zbigniew STANIK ◽  
Andrzej KUBIK
Keyword(s):  
Boiling Point ◽  
Operating Conditions ◽  
Brake Fluid ◽  
Braking System ◽  
Brake Discs ◽  
Safety And Reliability ◽  
Braking Distance ◽  
Set Up ◽  
Constrained Conditions ◽  
The Impact

The study determined the effect of increased water content in a brake fluid by measuring its hydration and boiling temperature and examining the impact of brake fluid wear on the safety and reliability of a braking system. Within the scope of work, the temperature of the brake discs was determined according to the braking distance. An experimental bench was set up to determine the boiling point of the hydrated brake fluid. The position is designed to reflect the operating conditions of intense braking and lead to the boiling of the brake fluid. A summary of all laboratory and operating tests of the brake fluid tested allowed the minimum braking distance to be determined after which the brake fluid of varying degrees of hydration (over various operating periods) could boil beyond the permitted boiling point.

scholarly journals Method of calculating the design parameters of a modulator anti-lock braking system with a high flow of working fluid

2021 ◽  
Vol 110 ◽  
pp. 199-210
Author(s):  
Mikhail ZHILEVICH ◽  
Sergey ERMILOV ◽  
Denis KAPSKI ◽  
Yuriy VOVK ◽  
Oleg LYASHUK ◽  
...  
Keyword(s):  
Flow Rate ◽  
Pressure Difference ◽  
Maximum Flow ◽  
Brake System ◽  
Design Parameters ◽  
Working Fluid ◽  
Main Stage ◽  
Emergency Braking ◽  
Braking System ◽  
Braking Process

The design dimensions of the executive hydraulic cylinders of the brake system of heavy-duty mining dump trucks cause high fluid flow during the braking process. Therefore, dimensions of the anti-blocking system modulator spool pair require unique electromagnets or hydraulic amplifiers to control. These solutions do not allow the required modulator performance. Thus, a modulator scheme with a division of the flow of fluid from the source to the brake cylinders was developed. This scheme allows during emergency braking passing, an additional amount of fluid to cylinders through the valve, installed parallel to the main valve upon pressure increase phase and controlled by the pressure difference. The task is to develop a method for calculating the main structural dimensions of a modulator. The calculation of the valve of the second cascade, installed in parallel to the main stage, is carried out for the emergency braking mode with the maximum flow rate to ensure the required performance of the braking system. The balance of fluid flows equations is compiled at the key points. The flow rate of the fluid through each of the valves is determined by the Torricelli formula, and the pressure difference across the valves is assuned equal. The obtained relations allows building a family of Q-p curves, which can be used to select the diameter and stroke of the additional valve depending on the flow rate in the brake system.

scholarly journals FEATURES OF ADAPTIVE BRAKE CONTROL OF THE SECONDARY BRAKE SYSTEM OF A MULTI-AXLE VEHICLE

2021 ◽  
pp. 27-37
Author(s):  
Viktor Bogomolov ◽  
Valeriy Klimenko ◽  
Dmytro Leontiev ◽  
Oleksandr Kuripka ◽  
Andrii Frolov ◽  
...  
Keyword(s):  
Simulation Model ◽  
Road Safety ◽  
Road Surface ◽  
Brake System ◽  
Technical Literature ◽  
Adhesion Properties ◽  
The Road ◽  
Emergency Braking ◽  
Braking System ◽  
Braking Process

Problem. A malfunction of the service braking system of a wheeled vehicle (CTS) significantly affects road safety, especially when operating multi-axle vehicles with large masses. One of the ways to increase the level of road safety of multi-axle vehicles, when braking them using a spare (emergency) braking system, is the introduction of automated adaptive braking systems into the design of the brake drive of vehicles. The definition of the limits of the use of the adaptive braking system on vehicles with many axles is almost not disclosed in the scientific and technical literature, therefore, the issue of using such a system on vehicles with a large number of axles requires additional research. Purpose. The purpose of this work is to develop a simulation model for adaptive control of the braking process of a multi-axle vehicle using a spare (emergency) braking system, taking into account the simulation of the dynamics of the drive and the variability of the adhesion properties between the tire of the vehicle wheel and the road surface. Methodology. To achieve this goal, it is necessary to develop a simulation model of the brake drive in an adaptive mode, implement a model of the interaction of the tire with the road surface, and implement a model of the braking dynamics of a multi-axle vehicle in the event of a malfunction of its service brake system. Originality. The proposed key criterion (Kr) for changing the throttle section in electro-pneumatic pressure modulators, which provide adaptive air inlet or outlet from the corresponding brake chambers of the drive, during simulation, made it possible to simulate the operation of the drive circuits in the adaptive mode. It has been established that, depending on the potential for the realization of the adhesion between the tires of automobile wheels and the road surface, the pressure in the electro-pneumatic brake drive with its adaptive regulation can be increased by no more than 0.04 MPa.

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 Study on Pressure Change Rate of the Automatic Pressure Regulating Valve in the Electronic-Controlled Pneumatic Braking System of Commercial Vehicle

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 938
Author(s):  
Hanwei Bao ◽  
Zaiyu Wang ◽  
Zihao Liu ◽  
Gangyan Li
Keyword(s):  
Control Method ◽  
Pressure Change ◽  
Autonomous Driving ◽  
Commercial Vehicles ◽  
Change Rate ◽  
Braking System ◽  
Theoretical Support ◽  
Automatic Pressure ◽  
Braking Process ◽  
Vehicle Dynamic Model

In contrast to the traditional pneumatic braking system, the electronic-controlled pneumatic braking system of commercial vehicles is a new system and can remedy the defects of the conventional braking system, such as long response time and low control accuracy. Additionally, it can adapt to the needs and development of autonomous driving. As the key pressure regulating component in electronic-controlled pneumatic braking system of commercial vehicles, automatic pressure regulating valves can quickly and accurately control the braking pressure in real time through an electronic control method. By aiming at improving driving comfort on the premise of ensuring braking security, this paper took the automatic pressure regulating valve as the research object and studied the pressure change rate during the braking process. First, the characteristics of the automatic pressure regulating valve and the concept of the pressure change rate were elaborated. Then, with the volume change of automatic pressure regulating valve in consideration, the mathematical model based on gas dynamics and the association model between pressure change rate and vehicle dynamic model was established in MATLAB/Simulink and analyzed. Next, through the experimental test of a sample product, the mathematical models have been verified. Finally, the key structure parameters affecting the pressure change rate of the automatic pressure regulating valve and the influence law have been identified; therefore, appropriate design advice and theoretical support have been provided to improve driving comfort.

New Method to Determine the a-Si:H Pin Diode Series Resistance by Noise Measurements

1998 ◽  
Vol 507 ◽  
Author(s):  
F. Blecher ◽  
K. Seibel ◽  
M. Hillebrand ◽  
M. Böhm
Keyword(s):  
Series Resistance ◽  
Partial Information ◽  
Low Noise ◽  
Operating Conditions ◽  
New Method ◽  
Measuring System ◽  
Pin Diode ◽  
Noise Current ◽  
Current Voltage ◽  
Noise Measurements

ABSTRACTThe series resistance limits the linearity of photodiodes and decreases the efficiency of solar cells. It is usually determined from IV-measurements for moderate and high forward current density. This method, however, provides only partial information about Rs, since the series resistance depends on the operating point. An alternative method is based on noise measurements. System noise of the measuring system with a low-noise current-voltage converter has been investigated. A new method for extraction of photodiode series resistance from noise measurements is suggested. Noise measurements are carried out for a-Si:H pin diodes. The series resistance of an amorphous pin diode has been extracted for different operating conditions using the new measurement method.

Sign in / Sign up

Export Citation Format

Share Document