Instantaneous Braking Research Articles

Combinatorial Effects of Clay-Type Silicate and MgO on Friction Braking Performance of Hybrid Phenolic Composites

Abstract Halloysite (tubular), montmorillonite (platy), and wollastonite (acicular) type clay silicate morphologies-based magnesium oxide (MgO) filled compression-molded hybrid friction composites were fabricated followed by their mechanical (compressive), thermal (onset of degradation), thermo-mechanical (loss modulus), and tribological performance (CoF, fade, recovery, wear) evaluation. The friction-fade and friction-recovery due to braking-induced heating and cooling cycles vis-a-vis the instantaneous braking performances were evaluated following SAEJ661, on a chase-type friction tester. The combination of halloysite–MgO in the friction composite led to minimum fade (∼2.2%), whereas that of wollastonite–MgO showed a maximum friction coefficient (∼0.47) with enhanced rotor friendliness as indicated from optical surface profilometry. Montmorillonite–MgO-based composites showed a maximum wear resistance along with a greater extent of friction stabilization as supported by ID/IG data from Raman spectra. The performance attributes remained governed by the compressive stiffness of the friction composites, hardness, thermal stability, and morphological aspects of the clay-type silicates, and their induced contact dynamics as evident from scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM–EDX) studies. The heat dissipation mechanism, the disc temperature rise, and friction coefficient under instantaneous braking condition were found to be controlled by MgO in the composites. The study demonstrates that clay-type silicate morphologies in combination with MgO as a mild abrasive may lead to synergistic fade–recovery performance without compromising the compressive stiffness response of the braking surface, enabling increased wear resistance.

Modelling of elastoplastic, multi-scale and multi-contact problems: application to worm gears

A nonconventional application of worm gears exploits the irreversibility of these power transmission devices in order to realize fast emergency braking. This application can be used to secure lifting devices. A limiting factor in the design of these instantaneous braking systems is the residual deformations of the worm/wheel contacting teeth, due to the impact between them at each emergency stop. The prediction of these residual displacements requires solving of an elastic–plastic, multi-scale and multi-contact problem. Original numerical tools were developed in this study to solve the problem at global and local scales. The method has been validated by comparing the obtained results with 3D measurements on new and deformed worm/wheel pairs. In order to predict the issue of the worm gear after an impact, a criterion based on kinematic errors is proposed. Applying this criterion gives the maximal admissible torque for the braking system to be operational after the impact.

Impact of regenerative braking torque blend-out characteristics on electrified heavy road vehicle braking performance

Electric and hybrid vehicles use a co-operative brake system that consists of regenerative brake and friction brake with different dynamic characteristics to obtain adequate deceleration during braking. Hence, the mechanism of braking blend-out (that is the mechanism of switching off regenerative braking) may affect the vehicle braking performance. This work focusses on the development of various co-operative braking strategies (series and parallel) for electrified heavy road vehicles by considering instantaneous braking blend-out and ramp down braking blend-out characteristics. The developed co-operative braking strategies were evaluated in a Hardware-in-Loop experimental setup equipped with TruckMaker® software. The results showed that instantaneous braking blend-out has more impact on vehicle braking performance in terms of momentary magnitude change in the longitudinal deceleration, pitch angle and suspension deflection for a laden vehicle compared with an unladen vehicle on both dry and icy road surfaces. Ramp down braking blend-out reduced these momentary magnitude changes and thereby improved vehicle’s braking performance in terms of stopping distance and ride comfort. The results of this study indicate that ramp down braking blend-out is expected to improve the vehicle dynamic performance during active braking control due to the smooth transition between friction braking torque and regenerative braking torque.

Static structural and thermal analysis of brake disc with different cut patterns

Power transmission plays an important role in automobiles. Since the concern regarding safety in automobiles has been considered as a top priority, it is very much important to have a complete control over vehicle to make it stop. Brakes are the power interruption devices which absorb the kinetic energy of vehicle and bring it to the rest condition. Once the brakes are actuated, heat is generated due to the friction between pads and rotating disc. This heat generated is responsible for high temperature of the disc. As brakes convert friction into heat, it must be dissipated through it in order to have limited temperature range of the entire system. Under this consideration drums brakes have been replaced by disc brakes as they are more efficient under steady and instantaneous braking conditions. In this paper, models were designed by using CATIA-V5 and then imported to ANSYS 16.2 for static structural and thermal analysis. The designing of discs was carried out considering its application for a two wheeler of 200-250 cc engine capacity. The aim of this paper is to study the heat distribution and the overall deformation of the discs having different cut patterns. Further an extension to this work, an attempt has been made to investigate different aspects like deformation and temperature distribution by varying the alloy materials for discs. This analysis has helped us a lot to understand the behavior of different materials under realistic conditions. The paper is then concluded with the best material and cut patterns in terms of strength, factor of safety and heat dissipation.

Static structural and thermal analysis of brake disc with different cut patterns

Power transmission plays an important role in automobiles. Since the concern regarding safety in automobiles has been considered as a top priority, it is very much important to have a complete control over vehicle to make it stop. Brakes are the power interruption devices which absorb the kinetic energy of vehicle and bring it to the rest condition. Once the brakes are actuated, heat is generated due to the friction between pads and rotating disc. This heat generated is responsible for high temperature of the disc. As brakes convert friction into heat, it must be dissipated through it in order to have limited temperature range of the entire system. Under this consideration drums brakes have been replaced by disc brakes as they are more efficient under steady and instantaneous braking conditions. In this paper, models were designed by using CATIA-V5 and then imported to ANSYS 16.2 for static structural and thermal analysis. The designing of discs was carried out considering its application for a two wheeler of 200-250 cc engine capacity. The aim of this paper is to study the heat distribution and the overall deformation of the discs having different cut patterns. Further an extension to this work, an attempt has been made to investigate different aspects like deformation and temperature distribution by varying the alloy materials for discs. This analysis has helped us a lot to understand the behavior of different materials under realistic conditions. The paper is then concluded with the best material and cut patterns in terms of strength, factor of safety and heat dissipation.

Modeljuvannja ta optymizacija rezhymiv ruhu vantazhopidjomnyh mashyn i mehanizmiv u procesi pusku/galmuvannja za kryterijem minimumu pytomoi energii. II

The model is substantiated and dynamic optimization of the modes of movement of load-lifting machines and mechanisms in the processes of their braking on the criterion of the minimum of specific energy is realized. The use of the standard method and the scheme of calculating the swinging fluctuations of the load on the ropes of the bridge crane on the model of a two-mass system allows us to establish, on the basis of the specified power-strength criterion, the basic parameters of the modes of movement of bridge cranes, which satisfy certain qualities (minimize their energy characteristics), as well as determine the duration of transients (inhibition cranes to their full stop) for optimal modes of operation of cranes of different design and purpose). The realized approach to dynamic optimization of the modes of movement of load-lifting machines and mechanisms can be further used in the design, construction and real operation of mechatronic control systems by these machines and mechanisms that can provide tracking of all kinematic as well as power-supply parameters of the mechanical system in the processes of its braking for specified a criterion that will inevitably lead to the possibility of functioning of such a system in the energy-saving mode. The results obtained in the work can be used to clarify and improve the existing engineering methods of calculating load-lifting machines and mechanisms which are functioning in the following typical modes: start, reversal, instantaneous braking (stops), both at the stages of their design, construction, and in energy-saving modes of real operation.

Power-based electric vehicle energy consumption model: Model development and validation

The limited drive range (The maximum distance that an EV can travel.) of Electric Vehicles (EVs) is one of the major challenges that EV manufacturers are attempting to overcome. To this end, a simple, accurate, and efficient energy consumption model is needed to develop real-time eco-driving and eco-routing systems that can enhance the energy efficiency of EVs and thus extend their travel range. Although numerous publications have focused on the modeling of EV energy consumption levels, these studies are limited to measuring energy consumption of an EV’s control algorithm, macro-project evaluations, or simplified well-to-wheels analyses. Consequently, this paper addresses this need by developing a simple EV energy model that computes an EV’s instantaneous energy consumption using second-by-second vehicle speed, acceleration and roadway grade data as input variables. In doing so, the model estimates the instantaneous braking energy regeneration. The proposed model can be easily implemented in the following applications: in-vehicle, Smartphone eco-driving, eco-routing and transportation simulation software to quantify the network-wide energy consumption levels for a fleet of EVs. One of the main advantages of EVs is their ability to recover energy while braking using a regenerative braking system. State-of-the-art vehicle energy consumption models consider an average constant regenerative braking energy efficiency or regenerative braking factors that are mainly dependent on the vehicle’s average speed. In an attempt to enhance EV energy consumption models, the proposed model computes the regenerative braking efficiency using the instantaneous vehicle operational variables. The proposed model accurately estimates the energy consumption, producing an average error of 5.9% relative to empirical data. The results also demonstrate that EVs can recover a higher amount of energy in an urban driving environment when compared to high speed highway driving using the proposed model. Moreover, the study also compared different electric vehicles and quantified the impact of auxiliary systems, including the air conditioning and heating systems, on vehicle energy consumption levels using the proposed energy model. The study demonstrated that the use of the heating and air conditioning system could significantly reduce the EV efficiency and travel range.

INFLUENCE OF THE BRAKING FORCE DISTRIBUTION ON THE DIRECTIONAL STABILITY OF COMMERCIAL VEHICLES

A commercial vehicle with good active safety is singled out for distinction, in that it remains stable during critical situations and that can be controlled and brought to a safe standstill by the driver. Previous investigations have shown that the instantaneous braking force distribution between the front and the rear axle of a commercial vehicle is the dominant factor in the stability of the vehicle while braking. In this paper, the influence of the braking force distribution on the driving performance is investigated for different commercial vehicles with the aid of a simulation system. The results indicate that disharmonization of the braking force distribution may lead to situations which are not controllable any more by the driver. When equipping the vehicle with an anti–lock system, driving safety can be essentially improved. But the performance of the anti–lock system is also distinctly influenced by the layout of the braking system.

Control System Modeling for Automotive Brake Test-Bench Based on Discrete Closed-Loop and Phase-Locked Loop

According to the law of rigid body around fixed axis rotation, established the mathematical model of motor drive current and instantaneous rotational speed. From the ideal situation of the simulation, according to the same discrete interval of time equal to the same increment of spindle angular velocity conditions, established the discrete closed-loop control system model. In allusion to the disadvantage of calculating corresponding braking current by the instantaneous speed and the instantaneous braking torque measured during the last interval, proposed the control method of calculating braking current by the instantaneous speed and the instantaneous braking torque measured all discrete intervals before current time. Discussed emphatically the computer controlled method based on the discrete closed-loop and phase-locked loop theory which can be used to design the braking current. Evaluated the advantages and disadvantages of the model, and proposed the improved direction.