Browse Topic: Brake torque

Items (339)

Brake Judder Resolution through Experimental Testing

2026-26-0587To be published on 01/16/2026

Brake judder is a critical concern in modern automotive systems, impacting both vehicle performance and passenger comfort. This phenomenon manifests as undesirable vibrations during braking, often caused by various factors such as vehicle architecture, different wheelbase, brake design considerations, load distribution, suspension characteristics etc. These vibrations not only compromise braking efficiency but also affect the overall driving experience, making it a priority issue for automotive engineers and researchers. This paper investigates the root causes of brake judder in a M3 Bus category vehicle having pneumatic brake system, focusing on its mechanical aspects and operational dynamics. By employing a combination of experimental testing and analytical evaluations, the study delves into the influence of brake torque generation and its consumption during vehicle deceleration for different wheelbase vehicles having similar brake system, revealing discrepancies that contribute to

Mundkar, Rameshwar, Shete, Rahul, Nayak, Nihar, Gavade, Sarjerao

Optimizing Brake Pedal Feel and Driver Comfort in Buses with Pneumatic Braking Systems

2026-26-0536To be published on 01/16/2026

Brakes are a critical safety component in vehicles, and every parameter of the braking system plays a vital role in vehicle operation. Among these, brake pedal feel and driver confidence are key factors, in addition to achieving the required brake force, deceleration, and stopping distance. These aspects depend on the system-generated torque, available pneumatic pressure, lining material properties, and Electronic Braking System (EBS) parameters. This paper focuses on the factors influencing brake pedal feel while maintaining a balance between driver comfort and confidence during bus operation. Under optimal braking conditions, brake pedal response and brake torque gradient must align with the driver’s deceleration demands. The braking system must respond promptly, completing the application in the shortest possible duration. The brake torque gradient values specified in the EBS file should neither be too low nor too high, and the brake pedal feel must remain consistent throughout the

Pujari, Sachin, Salunkhe, Swapnil, Ali, Tauqeer

HELICOPTER TURBOSHAFT ENGINE IDLE POWER SCHEDULING

AIR4121 (Current)

11/26/2025

The purpose of this AIR (Aerospace Information Report) is to provide aircraft and engine designers with a better understanding of helicopter turboshaft engine idle power characteristics and objectives to be considered in the design process. Idle is the lowest steady state power setting. At this setting, the engine typically does not produce enough power to obtain governed output shaft speed (i.e. the shaft speed is determined by the load imposed by the aircraft). In the aircraft, the engine is typically stabilized at this power setting after starting, prior to taxi and for some period of time after rotor shutdown for cool down prior to engine shutoff. Traditionally, the aircraft designer wants idle power scheduled as low as possible and of course, does not want any resulting aircraft operational difficulties such as overcoming the rotor brake. The engine designer, however, desires a higher scheduled power because of the reduced probability of engine operational problems. The attributes

S-12 Powered Lift Propulsion Committee

A Study on Effect of Regenerative Braking on Vehicle Range and Axle Life.

2024-26-024001/16/2024

During braking condition in EVs, the braking energy is split between the friction braking & regenerative braking. The friction brake fraction will be lost as heat & regenerative brake fraction is converted into electrical energy. In regeneration mode the amount of energy harnessed depends on the regenerative torque available & the rate at which that torque is achieved. If the regenerative torque is higher and if the rate of achieving that torque is higher, energy harnessed will be higher. But higher regenerative torque & higher rate of torque affect the life of the axle components like bevel gear, crown wheel pinion, spider gear & bearing etc & causes gear failure like gear pitting on coast side if proper regeneration torque maps are not defined. This paper gives an outline on effect of different regenerative braking torque values and their rate on the vehicle range and reliability, failure & life of the axle components. Initially an ideal situation with 100% regeneration torque

S, Srivatsa, Pethkar, Shivanand, Ghosh, Sandeep

Calibration of an Inertial Measurement Unit and its Impact on Antilock Braking System Performance

2024-26-001401/16/2024

An Inertial Measurement Unit (IMU) provides vehicle acceleration that can be used in Active Vehicle Safety Systems (AVSSs). However, the signal output from an IMU is affected by changes in its position in the vehicle and alignment, which may lead to degradation in AVSS performance. Investigators have employed physics and data-based models for countering the impact of sensor misalignment, and the effects of gravity on acceleration measurements. While physics-based methods utilize parameters varying dynamically with vehicle motion, data-based methods require an extensive number of parameters making them computationally expensive. These factors make the above-explored methods practically challenging to implement on production vehicles. This study considers a 6-axis IMU and evaluates its impact on Antilock Braking System (ABS) performance by considering the IMU signal obtained with different mounting orientations, and positions on a Heavy Commercial Road Vehicle (HCRV). It then develops a

Dixit, Chitrartha, Gaurkar, Pavel, Ramakrishnan, Rajesh, Shankar Ram, C S, Vivekanandan, Gunasekaran, Sivaram, Sriram

Enhancing Meta Model of the Brake Pad Friction Coefficient using the Explainable Machine Learning

2022-01-117509/19/2022

As increasing system complexity and various customer demands result in the need for highly efficient vehicle development processes. Once the brake torque is predicted accurately during the driving scenario in the earlier stage, it will be able to prevent the changing the vehicle or brake system design to satisfy the legal regulation and customer requirement. As brake torque performance target allocate brake pad friction coefficient level and characteristic, the accurate friction coefficient prediction should be preceded for accurate prediction for brake torque. Generally, the friction coefficient of the brake pad is known to vary nonlinearly depending on the physical properties of the disc and the pad, as well as the rotational speed of the brake disc, the disc temperature, and the hydraulic pressure. Furthermore, it varies depending on the driving scenario even the same condition. Therefore, there was a need for a new method : machine learning to solve this problem. A Mixed Effect

Cho, Sunghyun, Bang, Sunghoon, Jang, Jiwoo, Kim, Youngjae

V4-002 FK test

SAE-PP-0095504/26/2022

Heavy vehicles are essential for the modern economy, delivering critical food, supplies, and freight throughout the world. Connected heavy vehicles are also driven by embedded computers that utilize internal communication using common standards. However, some implementations of the standards leave an opening for a malicious actor to abuse the system. One such abuse case is a cyber-attack known as the “Address Claim Attack.” Proposed in 2018, this attack uses a single network message to disable all communication to and from a target electronic control unit, which may have a detrimental effect on operating the vehicle. This article demonstrates the viability of the attack and then describes the implementation of a solution to prevent this attack in real time without requiring any intervention from the manufacturer of the target devices. The defense technique uses a bit-banged Controller Area Network (CAN) filter to detect the attack. Once an attack is discovered, the defender induces a

Mutagaana, Festo

Increasing the Effective AKI of Fuels Using Port Water Injection (Part II)

2022-01-052303/29/2022

This is part II of the paper on ‘Increasing the Effective AKI of Fuels Using Port Water Injection’ In the United States, the metric used to quantify the anti-knock performance of fuels is Anti Knock Index (AKI), which is the average of Research Octane Number (RON) and Motor Octane Number (MON). Fuels with higher AKI are expected to have a better knock mitigating properties, which enables the engine to be run closer to Maximum Brake Torque (MBT) spark timing in the knock limited region. The work done in part I of the study quantified the amount of water required (as a ratio with fuel and absolute) to increase the performance of low AKI fuels in order to match their performance to that of a higher AKI reference fuel, thus increasing their ‘effective AKI’. This paper builds upon the work done in part I of the study by repeating a part of the test matrix with Primary Reference Fuels (PRFs), with iso-octane (PRF100) as the reference fuel and lower PRFs used to match its performance with the

Gopujkar, Siddharth, Worm, Jeremy, Barros, Sam, Bonfochi Vinhaes, Vinicius, Hansley, William

Systems of Automatic Brake Torque Reduction on the Wheels of One Axle of the Car

2021-01-126610/11/2021

Braking mechanisms have the most variation in performance of all of the elements of the braking system. Instability of braking torques on the wheels of one axle of the vehicle leads to the appearance of the braking forces unevenness, and then- to the vehicle skidding during braking. At one time, the appearance of open-type disc brakes made it possible to reduce the unevenness of the braking forces on the sides of the car due to their higher characteristics of energy intensity and stability. However, the lack of feedback between the left and right disc brakes mounted on the same axle of the vehicle does not allow reducing the unevenness of the braking forces to an acceptable minimum. The authors of the work studied and proposed several systems for automatic reduction of the braking torques unevenness for braking mechanisms mounted on the wheels of one axle.

Podrigalo, Mikhail, Kholodov, Mykhailo, Stepanov, Victor, Soloviov, Oleh, Aleksandrov, Yevgeniy, Volontsevych, Dmytro, Morozov, Oleksandr

Investigation and Mitigation of Brake Squeal Noise in Medium Commercial Vehicle

2020-01-160710/05/2020

The braking systems for modern day commercial vehicles with GVWs ranging above 7.5 metric tons use the typical s-cam drum brake system, where pressurized air is the actuating medium. The s-cam drum brake systems are popular today even after the advent and penetration of air disc brake systems, the main reasons being, cost-effectiveness, robustness, satisfactory performance and good component life. However, the brake systems of commercial vehicles (both M and N category) are frequently grappled with NVH issues particularly in the form of brake squeal noise (low frequency and high frequency). The noise with frequency more than 500 Hz can be generally defined as brake squeal. There has been a lot of work done and is being continued, at theoretical level, analytical level and experimental level to tackle with this issue. But the underlying physical phenomena causing the brake squeal are quite dynamic in nature and have a probabilistic chance of occurrence, which makes it difficult to give

Kadam, Rohit, Chandel, Abnish, Umbare, Deepak, Babel, Prashant

Air Brake Performance and Wear Test Code Commercial Vehicle Inertia Dynamometer

J2115_202008 (Current)

08/20/2020

This SAE Standard provides test procedures for air and air-over-hydraulic disc or drum brakes used for on-highway commercial vehicles over 4536 kg (10000 pounds) GVWR. This recommended practice includes the pass/fail criteria of Federal Motor Vehicle Safety Standard No. TP-121D-01.

Truck and Bus Foundation Brake Committee