Frequent Braking Research Articles

On-line junction temperature identification of converter power devices

Abstract Traction converters often fail or age due to long operation hours, complex conditions, and frequent braking, mainly caused by overheating or temperature fluctuations. Monitoring the temperature at the junction of power device is crucial for system reliability. To achieve this, the electric-heat coupling models of IGBT are studied. Models for IGBT’s switching and conduction processes were created using its data sheet, yielding a power loss model linked to junction temperature. A Foster thermal network model for IGBT was then established, deriving the equation for temperature change when losses act as heat sources. Combining these models, an electric-heat coupling model was built on the SIMULINK platform, applied to predict and simulate junction temperature in a two-level inverter, generating a temperature-time image. Finally, an experimental test platform for a two-level SVPWM-modulated inverter was set up, using an infrared sensor to measure IGBT’s steady-state junction temperature. This was compared with simulation results to verify the model’s accuracy.

Enhancing Estimating the Charge Level in Electric Vehicles: Leveraging Force Fluctuation and Regenerative Braking Data

Accurate determination of the state of charge is vital to optimize the performance and lifespan of electric vehicle batteries. Traditional methods which rely on battery models and direct measurements can be error-prone due to fluctuating operating conditions and battery degradation over time. Regenerative braking systems are crucial in electric and hybrid vehicles for improving energy efficiency by transforming kinetic energy into electrical energy during braking. However, force fluctuation is a challenge that can affect the performance and comfort of regenerative braking. It is known to us that electric motors and generators used in regenerative braking have non- linear torque characteristics, especially at low speeds, leading to inconsistent braking force. Variations in road conditions, such as wet or uneven surfaces, can affect the grip of the tires, leading to fluctuations in deceleration. Interactions of regenerative braking system with conventional friction brakes can cause force fluctuations, especially during the transition between the two systems. This study introduces an improved state of charge estimation technique based on force fluctuation and a regenerative braking system. This research shows that this approach significantly enhances state of charge accuracy compared to traditional methods, especially in urban driving conditions with frequent braking. The findings underscore the potential of using regenerative braking as well as force fluctuation condition data as a valuable input for state of charge estimation, ultimately leading to better battery management and an extended electric vehicle range.

Design Optimization of Underground Mining Vehicles Based on Regenerative Braking Energy Recovery

This article addresses the issue of energy waste resulting from frequent braking of underground mine cars and proposes an optimization design to address this. The proposed solution involves the installation of a regenerative braking device within the mine cars to capture and reuse the energy wasted during braking. This implementation improves the endurance capabilities of the underground mine cars. The article begins by analyzing the working characteristics of underground mine cars and proposing a design optimization method based on regenerative braking energy. Subsequently, a regenerative braking device specifically designed for underground mine cars is introduced. Finally, through physical modeling, a comparison is made between the energy consumption of the underground mine cars before and after the installation of the energy recovery system, allowing for an estimation of the actual benefits of energy recovery. The results demonstrate that the regenerative braking system successfully recovers approximately 60% of the braking energy during operation, resulting in an improvement of around 20% in the endurance capabilities of the underground mine cars. This significant enhancement contributes to the improved energy utilization efficiency of coal mine electric cars, reducing system energy consumption and lowering CO2 emissions.

Thermal and mechanical analysis of wheel rim in Formula 1 vehicles

The wheel rim is a metal or alloy component that holds the tire and connects it to the vehicle. The wheel rims of Formula 1 cars are exposed to thermal stresses during the race and frequent braking at high speeds. In addition to thermal resistance, wheel rims must possess high mechanical durability. Therefore, material selection is crucial, along with the designs of the wheel rims. In the production of wheel rims for Formula 1 vehicles, magnesium, aluminium, and carbon fibre wheel rims are commonly used. Each of these materials has its advantages and limitations. Optimization processes in Formula 1 technology aim to reduce mass while increasing mechanical and thermal properties. Therefore, alloys used in wheel rim production are continuously evolving. In this study, deformation, stress, and temperature values were investigated using the Computational Fluid Dynamics (CFD) method by exposing Mg AZ80, Al 6061-T6, and carbon fibre to conditions of 300?C temperature, 1 MPa pressure, and 300 km/s speed. Turbulence modelling was carried out using the k-? method in numerical analyses, which utilized a mesh file consisting of approximately 2 million grids. As a result, the highest deformation in mechanical pressure analyses was obtained using Mg AZ80 material. In contrast, carbon fibre achieved the lowest deformation value in the analysis. Regarding thermal results, the lowest temperature value of 282.75?C was obtained from the wheel rim made of carbon fibre, whereas with the use of Mg AZ80 material, this value reached up to 292.03?C. Considering these values, it was concluded that carbon fibre is the most suitable wheel rim material for Formula 1 race cars.

Analisis Pola Keausan Brake Shoe pada Kereta Mass Rapid Transit Jakarta

Brake shoe is one of the components on train that has an important role in braking process, to perform braking brake shoe rubs against the wheel. Friction between the brake shoe and wheel continuously can cause wear on brake shoe. The purpose of this study is to determine the wear rate and service life of brake shoe and main cause of brake shoe wear faster. The research method used in this research is descriptive quantitative method. Based on the results of the study, at a distance of about 7000 km to 10000 km the brake shoe on trailer car experienced wear of about 4 mm to 8 mm while brake shoe on motor car was about 1 mm to 3 mm. The service life of brake shoe on trailer car when mileage reaches 40000 km to 50000 km while on the motor car it can reach 70000 km to 90000 km and the main cause of brake shoe wear is faster due to the large braking force generated due to the frequent braking of the train so that the friction on the brake shoe and the wheel is more frequent and can cause hot temperatures which make wear occur faster.

Mathematical Modeling the Performance of an Electric Vehicle Considering Various Driving Cycles

Currently, the estimated range of an electric vehicle is a variable value. The assessment of this power reserve is possible by various methods, and the results of the assessment by these methods will be quite different. Thus, building a model based on these cycles is an extremely important task for manufacturers of electric vehicles. In this paper, a simulation model was developed to determine the range of an electric vehicle by cycles of movement. A mathematical model was created to study the power reserve of an electric vehicle, taking into account four driving cycles, in which the lengths of cycles and the forces acting on the electric vehicle are determined; the calculation of the forces of resistance to movement was carried out taking into account the efficiency of the electric motor; thus, the energy consumption of an electric vehicle is determined. The modeling of the study of motion cycles on the presented model was carried out. The mathematical evaluation of battery life was based on simulation results. Simulation modeling of an electric vehicle in the MATLAB Simulink software environment was performed. An assessment of the power reserve of the developed electric vehicle was completed. The power reserve was estimated using the four most common driving cycles—NEDC, WLTC, JC08, US06. Studies have shown that the highest speed of the presented US06 cycle provides the shortest range of an electric vehicle. The JC08 and NEDC cycles have similar developed speeds in urban conditions, while in NEDC there is a phase of out-of-town traffic; therefore, due to the higher speed, the electric vehicle covers a greater distance in equal time compared to JC08. At the same time, the NEDC cycle is the least dynamic and the acceleration values do not exceed 1 m/s2. Low dynamics allow for a longer range of an electric vehicle; however, the actual urban operation of an electric vehicle requires more dynamics. The cycles of movement presented in the article provide a sufficient variety and variability of the load of an electric vehicle and its battery over a wide range, which made it possible to conduct effective studies of the energy consumed, taking into account the recovery of electricity to the battery in a wide range of loads. It was determined that frequent braking, taking into account operation including in urban traffic, provides a significant return of electricity to the battery.

Study on the influence of running parameters on the temperature field of disc brake on long downhill road

The braking system of the vehicle is liable to fail due to the high temperature of frequent braking in the downhill road. This paper analyzes the influence of the main operating parameters of the vehicle on the maximum temperature of the brake disc surface. Firstly, the mechanical characteristics of the vehicle on the long downhill road are analysed, and the Finite Element Model of the brake disc/friction plate is established; Secondly, the effects of gradient, vehicle weight, brake speed threshold and brake pressure on the braking cycle and disc brake temperature field on long downhill roads are studied. The results show that when the gradient increases from 3° to 9°, the maximum temperature of the brake disc increases by 41.6%, while when the vehicle weight increases from 4 to 7 tons, the brake disc temperature only increases by 16.7%. For the braking speed threshold and braking force that the driver can control, selecting a smaller braking force and a lower braking speed threshold can better inhibit the temperature rise of the brake disc. Finally, the effectiveness of the simulation method is verified by the real vehicle test. It is found that the average measured temperature is 9.2%–11.8% lower than the simulated average temperature. It is considered that the modified temperature value can be obtained by reducing the maximum temperature of the simulation model by 5%–6%.

Development of brake activity measurement method for heavy-duty vehicles

ABSTRACT Tailpipe PM (particulate matter) emissions have been reduced due to decades of tightening regulations, however non-tailpipe PM emissions are not regulated and are expected to become a significant source of traffic-related PM emissions. Previous studies have focused on emission measurement from laboratory and track tests. Their findings suggest brake wear PM emission rates are dependent on brake activity. Therefore, it is important to characterize brake emissions by first understanding the real-world brake activity from many different vehicle vocations and driving conditions. The goal of the current study is to establish a test method and analysis for brake activity measurements of heavy-duty vehicles. In this study, brake fluid pressure and brake pad temperature were measured for a heavy-duty vehicle during chassis and on-road driving tests. The chassis tests consisted of the Central Business District (CBD) cycle representative of a repetitive stop-and-go driving pattern of a bus, and the Urban Dynamometer Driving Schedule (UDDS) cycle representative of urban driving conditions of heavy-duty vehicles. The on-road tests consisted of a local Riverside City route focused on urban roads at low vehicle speeds with frequent braking, while the second route from Riverside City to Victorville focused on highway driving and downhill braking. The brake pad temperature of the triplicate CBD cycle gradually increased linearly with a slope of 2.3°C/min and the temperature per kinetic energy lost during braking increased by 2.3 × 10−5°C/J for the CBD cycle. The UDDS cycles had the largest kinetic energy loss between 3.2 × 103 to 3.0 × 105 J in the histogram. The local Riverside city route brake temperature increased by 2.0°C/min. The kinetic energy loss for the on-road tests were one order of magnitude larger than that of the dynamometer tests due to brake events occurring under higher speeds. Implications: The non-tailpipe source contributions to traffic related particulate matter (PM) emissions have surpassed that of tailpipe emissions. The results of this work provide a measurement method to obtain brake activity information for a heavy-duty vehicle, which is critical estimating emission inventory accurately.

Energy-Efficient Optimization Method of Urban Rail Train Based on Following Consistency

Because of the short distance between stations in urban rail transit, frequent braking of urban rail trains during operation will generate a large amount of regenerative braking energy. Urban rail trains can reduce their actual traction energy consumption using regenerative braking energy. Therefore, an energy-efficient optimization method for urban rail trains is proposed. By taking the punctuality of trains as the premise, the weighted acceleration of trains is taken as the synergetic variable, the synergetic coefficient is introduced to construct the following consistency model, and its convergence is proved. By analyzing the influencing factors of the following consistency coordination time, an adaptive parameter adjustment strategy is designed to solve the latest secondary traction time and the corresponding maximum speed of the primary traction. In order to save communication resources, the event trigger function is used to construct trigger conditions, and the consistency algorithm is used to update the cooperative controller. The simulation results show that the weighted acceleration of the follower train achieves the following consistency on the premise of ensuring punctuality, and the actual traction energy consumption of the follower train is reduced by 5.73%. The proposed method provides a new strategy for the energy-efficient operation of urban rail trains.

Dynamics analysis of train-track-bridge coupled system considering spatial flexibility of high piers and system longitudinal vibrations

High-pier railway bridges are mostly applied in mountainous areas. Due to the large spatial flexibility of the high piers under train dynamic loads, especially under braking conditions, the wheel-rail (WR) dynamic interaction may become more intense in the longitudinal direction, which could induce larger deformation and impact on the train-track-bridge (TTB) coupled system. To investigate the dynamic characteristics of such complex and large system during train braking condition, a 3D train-slab track-high pier bridge (TTHPB) coupled dynamics model is established and verified by considering the system longitudinal vibrations and the spatial flexibility of high piers. In this work, the influence of concerned bridge height from 60 to 160 m on the dynamic performances of the TTHPB system under train braking condition is studied. Results indicate that the operation speed has a significant effect on carbody acceleration and WR force. The longitudinal carbody acceleration due to its high-frequency vibration, as well as its noticeable amplitude induced by the long-time frequent braking, should be carefully considered in the evaluation of riding comfort index. The longitudinal dynamic behaviour of the high pier bridge is considerable and should be paid full attention to in bridge design compared with the other two directions.

Understanding the Interactions Between Driving Behavior and Well-being in Daily Driving: Causal Analysis of a Field Study.

BackgroundInvestigating ways to improve well-being in everyday situations as a means of fostering mental health has gained substantial interest in recent years. For many people, the daily commute by car is a particularly straining situation of the day, and thus researchers have already designed various in-vehicle well-being interventions for a better commuting experience. Current research has validated such interventions but is limited to isolating effects in controlled experiments that are generally not representative of real-world driving conditions.ObjectiveThe aim of the study is to identify cause–effect relationships between driving behavior and well-being in a real-world setting. This knowledge should contribute to a better understanding of when to trigger interventions.MethodsWe conducted a field study in which we provided a demographically diverse sample of 10 commuters with a car for daily driving over a period of 4 months. Before and after each trip, the drivers had to fill out a questionnaire about their state of well-being, which was operationalized as arousal and valence. We equipped the cars with sensors that recorded driving behavior, such as sudden braking. We also captured trip-dependent factors, such as the length of the drive, and predetermined factors, such as the weather. We conducted a causal analysis based on a causal directed acyclic graph (DAG) to examine cause–effect relationships from the observational data and to isolate the causal chains between the examined variables. We did so by applying the backdoor criterion to the data-based graphical model. The hereby compiled adjustment set was used in a multiple regression to estimate the causal effects between the variables.ResultsThe causal analysis showed that a higher level of arousal before driving influences driving behavior. Higher arousal reduced the frequency of sudden events (P=.04) as well as the average speed (P=.001), while fostering active steering (P<.001). In turn, more frequent braking (P<.001) increased arousal after the drive, while a longer trip (P<.001) with a higher average speed (P<.001) reduced arousal. The prevalence of sunshine (P<.001) increased arousal and of occupants (P<.001) increased valence (P<.001) before and after driving.ConclusionsThe examination of cause–effect relationships unveiled significant interactions between well-being and driving. A low level of predriving arousal impairs driving behavior, which manifests itself in more frequent sudden events and less anticipatory driving. Driving has a stronger effect on arousal than on valence. In particular, monotonous driving situations at high speeds with low cognitive demand increase the risk of the driver becoming tired (low arousal), thus impairing driving behavior. By combining the identified causal chains, states of vulnerability can be inferred that may form the basis for timely delivered interventions to improve well-being while driving.

Study on Speed Planning of Signalized Intersections with Autonomous Vehicles Considering Regenerative Braking

In order to reduce the energy consumption caused by the frequent braking of vehicles at signalized intersections, an optimized speed trajectory control method is proposed, based on braking energy recovery efficiency (BERE) in connection with an automated system for vehicle real-time interaction with roadside facilities and regional central control. Our objectives were as follows; firstly, to establish the simulation model of the hybrid energy regenerative braking system (HERBS) and to verify it by bench test. Secondly, to build up the genetic algorithm (GA) optimization model for the deceleration stopping of the HERBS. Then, to obtain signal light status and timing information to be the constraints; the BERE is to be the optimized objective, resulting in optimization for the speed trajectory under the deceleration stopping condition of a single signalized intersection. Finally, vehicle simulations in ADVISOR software are utilized to validate the optimization results. The results show that the BERE during deceleration stopping at a single signalized intersection after the speed trajectory optimization is 36.21% higher than that of inexperienced drivers, and 7.82% higher than that of experienced drivers.

The Design and Magnetic Field Analysis of a Double Rotor Permanent Magnet Braking Device

During long-term continuous braking, high-intensity braking, or frequent braking, the temperature of the brake disc or brake drum will increase significantly, resulting in a decrease in the friction coefficient, the aggravation of the wear degree, and the dangerous heat recession of partial or even total loss of braking efficiency. This paper focuses on an innovative double rotor permanent magnet braking device, which is located on the inner side of the wheel hub, to improve the heat decay resistance of the friction braking device. The structure and principle of the double rotor permanent magnet braking device were given, and its main structural parameters were designed, calculated, and optimized. The geometric model and finite element model of the double rotor permanent magnet braking device were established. The static and transient magnetic field analysis and the braking torque characteristic analysis of the double rotor permanent magnet braking device were carried out by using Maxwell electromagnetic analysis software. The results show that the magnetic flux density in the working area of the double rotor permanent magnet braking device increases with the increase in rotation speed, the braking torque changes with the change of rotation speed, and the maximum braking torque occurs in the low-speed area, which is consistent with the theoretical calculation results. This provides a theoretical basis for the follow-up prototype test of the double rotor permanent magnet braking device.

CFD Analysis of the Influence of the Front Wing Setup on a Time Attack Sports Car’s Aerodynamics

In time attack races, aerodynamics plays a vital role in achieving short track times. These races are characterized by frequent braking and acceleration supported by aerodynamic downforce. Usually, typical cars are modified for these races by amateurs. Adjusting the aerodynamic solutions to work with bodies developed for other flow conditions is difficult. This paper presents the results of a numerical analysis of the effects of installing a straight wing in front of or above the body on the modified vehicle system’s aerodynamic characteristics, particularly on the front wheels’ aerodynamic downforce values. The paper presents the methodology and results of calculations of the aerodynamic characteristics of a car with an additional wing placed in various positions in relation to the body. The numerical results are presented (Cd, Cl, Cm, Clf, Clr), as well as exemplary pressure distributions, pathlines, and visualizations of vortex structures. Strong interactions between the wing operation and body streamline structure are shown. An interesting and unexpected result of the analysis is that the possibility of obtaining aerodynamic downforce of the front wheels is identified, without an increase in aerodynamic drag, by means of a wing placed in a proper position in front of the body. A successful attempt to balance the additional downforce coming from the front wing on the front axle is made using a larger spoiler. However, for large angles of attack, periodically unsteady flow is captured with frequency oscillations of ca. 6–12 Hz at a car speed of 40 m/s, which may interfere with the sports car’s natural suspension frequency.

EXPERIMENTAL INVESTIGATION &amp; ANALYSIS OF HEA TRANSFER CHARACTERISTICS IN AUTOMOTIVE MMC DISC BRAKE UNDER STEADY STATE AND DYNAMIC CONDITIONS

During braking process, the kinetic energy of vehicle reduces and gets converted in thermal energy due to friction between disk and brake pads. The disk brake is used to retard the motion of vehicle by pressing brake pads against disk rotors. The frequent braking or panic braking results in overheating of brake disks which may result in brake fade. It is therefore essential to test newer materials which are more effective and possess better heat transfer characteristics than conventional cast iron material. The current research investigates the application of Al MMC material for ATV disk brake using experimental and numerical techniques. The numerical analysis is conducted on both conventional cast iron and Al MMC disk brake under steady state conditions and dynamic conditions. The dynamic condition testing involved testing of disk brake with externally flowing air at 2.5m/s and 5m/s using techniques of Computational Fluid Dynamics (CFD). The CAD model of ATV disk brake is developed in Creo design software and CFD analysis is conducted using ANSYS CFX. The turbulence model used for analysis is RNG k-epsilon. The temperature and heat flux are determined for disk brake under steady state and dynamic conditions. The results have shown that disk brake made from Al MMC possess better heat transfer characteristics as compared to conventional cast iron and cooling time also reduces with increase in external air speed.

СОВЕРШЕНСТВОВАНИЕ СИСТЕМЫ РЕКУПЕРАЦИИ ЭНЕРГИИ ЛЕСОВОЗНОГО ТЯГАЧА С ПРИЦЕПОМ-РОСПУСКОМ

The place of road transport in logging production has been considered. The main advantages of using timber tractors with timber drags in comparison with other layout schemes of timber road trains have been described. Conse-quences of dynamic loads acting on the pivot of the turning bunk of a timber-carrying area from frequent braking of a timber tractor with a timber drag have been given. Based on the analysis of scientific works of foreign scientists, the promising direction of research in the field of recuperation of various types of energy in road transport is substantiated, which makes it possible to reduce dynamic loads during braking in the pivot pin and at the same time accumulate, with subsequent useful use, energy unproductively dissipated into the surrounding space from the energy forces of the trailer with a pack of whips. The design of the main manufacturers of platforms for timber haulers with timber drags has been described. The requirements for timber haulers with timber drags operated on public roads have been considered. The main forces acting on the links of a timber tractor with a timber drag during braking have been analyzed. Diagrams of the mutual positions of a timber tractor with a timber drag when moving along a timber road on the rise, downhill and turn have been given. The analysis of the dependences of the forces arising in the pivot of the swivel bunk of a timber platform during the movement of a timber tractor with a timber drag on the turning radius and speed of movement has been carried out. A promising design of a recuperative bolster device for a timber haulage site has been proposed. It enables to accumulate hydraulic energy during frequent braking of a timber tractor with a timber drag, followed by its use in the process of loading and unloading timber by a hydraulic manipulator

A regenerative braking energy recuperation from elevator operation in building by active rectifier

Elevators- means of vertical transportation to carry people and goods are an indispensable part in offices, high-rise buildings, hospitals, commercial areas, hotels, car-parks when blooming urbanization develops worldwide. However, the level of energy consumption in elevator operation is significant, so energy saving solutions have been outlined and applied in practice. With frequent braking phases, regenerative braking energy is wasted on braking resistors. Therefore, this paper proposes regenerative braking energy recuperation method for elevator operation in building by active rectifiers enabling the braking energy to be fed back into utility grid. Simulation results conducted by MATLAB with data collected from OCT5B building-RESCO new urban area, Ha noi, Vietnam have verified saving energy of using active rectifiers replacing diode rectifiers up to 33%.

Decreasing Emissions of PM by Vehicles through Brake Energy Recovery

A significant contribution to the formation of PM 10 and PM 2.5 in the atmosphere of large cities is made by frequent braking by friction brake mechanisms. The author considers electrodynamic regenerative braking as one of the advantages of hybrid and electric vehicles, which can significantly reduce the formation of PM during braking. Using experimental studies, the author estimates the wear of the brake pads of the same vehicle during regenerative and mechanical braking. During the experiment, a series of acceleration and braking cycles was performed from a given speed to a complete stop, after which the friction brake pads were dismantled and their weight was measured. Then, during the calculation and comparison, the PM emission reduction is determined in a test with braking energy recovery.

Transient Thermal Analysis of Tungsten Carbide and Hafnium Carbide Disc Brake Rotor

Disc brakes are used in vehicles to slow down or stop the angular and linear velocity of the wheels that uses calipers to squish a set of two similar pads versus the disc. During this process, the disc or rotor gets heated up due to friction from the pads. Frequent braking will cause abundant heating of the disc or rotor. Therefore, it is crucial in quick dissipation of heat from the rotor disc. Keeping this in mind, a comparison between the different materials is modelled in Creo parametric and it is analyzed in ANSYS 2019 R3, in this paper transient analysis of Cast Iron,Tungsten carbide and Hafnium carbide is modelled and analyzed using Creo and ANSYS 2019 R3 respectively. The best among them is selected as a material for the disc rotor.

Research on Temperature and Braking Performance of Water-Cooled Eddy Current Retarder

Trucks have the problems of frequent braking and long-term braking during long-slope transportation. As the temperature of the traditional eddy current retarder is as high as 500 °C during braking, the braking torque of the retarder is seriously degraded. According to the principle of eddy current braking and current thermal effect, this paper proposes an eddy current retarder in which both the stator and the excitation coil are water-cooled. The multi-field coupling and bidirectional data transmission model of stator temperature field, coil temperature field and transient electromagnetic field are established. The relationship between the braking torque and the working time is analyzed under continuous braking conditions, considering the stator temperature and the temperature of the excitation coil. It provides theoretical support for the optimal design of the retarder. A test prototype of a water-cooled eddy current retarder was manufactured, and a bench drag test was carried out. The calculation results show that the numerical simulation method of coupling between the stator temperature field, the coil temperature field and the transient electromagnetic field is adopted, and the simulation values of the braking torque is in good agreement with the experimental values.