Comparison of Heavy Truck Foundation Brake Performance Measured with an Inertia Brake Dynamometer and Analyses of Brake Output Responses to Dynamic Pressure Inputs

Hoover, Richard L.; Zagorski, Scott B.

doi:10.4271/2005-01-3611

Cited by 3 publications

(1 citation statement)

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“…In Figure 7, the brake torque is modeled as a linear piecewise function of the brake chamber pressure [5,9,28], which is derived using four test data (red dots). The first dot is the pop-out pressure (P 0 ) that is typically set at 7 psi [5,9,28,29], below which there is no brake torque since there is no or negligible contact between the brake shoes and drum. One can think of this as the minimum pressure to overcome the force of the return spring.…”

Section: Brake Torque Modelingmentioning

confidence: 99%

Detailed Modeling of Pneumatic Braking in Long Combination Vehicles

Zhang¹,

Sun²,

Chen³

et al. 2021

SAE Int. J. Commer. Veh.

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A detailed model for pneumatic S-cam drum brake systems is developed and integrated into a multibody dynamic model for a 33-ft A-double long combination vehicle (LCV). The model, developed in TruckSim ® , is used to study the dynamics of LCVs during straight-line braking at various speeds. It includes the response delay in braking that occurs from the time of application to when the brakes are applied at the drum for all axles. Additionally, the model incorporates an accurate characterization of brake torque versus chamber pressure at different speeds, along with the antilock brake system (ABS) dynamics, to yield an accurate prediction of the vehicle's deceleration during braking. The modeling results are compared with test results at speeds ranging from 20 mph to 65 mph on dry pavement. A close match between the model's prediction and test results is observed. The model is then used to perform a parametric study that evaluates braking distance and time for different pavement coefficients of friction (μ p ) at various speeds. The results indicate a distinct nonlinear relationship between μ p and braking dynamics. At various μ p , stopping time increases linearly with speed, as perhaps expected. Stopping distance, however, increases nonlinearly for a larger μ p and linearly for a smaller μ p versus speed. At a given speed, stopping time increases nonlinearly with a reduced μ p , whereas stopping distance increases relatively linearly with a reduced μ p .

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