Evaluation of Tractor-Trailer Combination Braking Performance in Different Operating Conditions

Abstract

In the trials of the present work, a double-axle trailer with a carrying capacity of 6 tons and a hydraulically effective mechanical brake were used as a tractor towed car. There is a hydraulic brake system on each axle of the agricultural trailer. In order to separate the brake system on the axles from each other, a hydraulic mechanically controlled 2/2 directional control valve was mounted on both hydraulic brake system inlets. The study was carried out at constant speed (25 km h-1), on stabilized road conditions, with 4 different braking modes and 4 different trailer loads. On stabilized ground, the braking acceleration (deceleration) of the tractor (without trailer) is 5.51 m s-2. The braking acceleration of the combination is 2.15 m s-2 under the condition that the trailer's carrying capacity was 30% more loaded and without brakes, and the braking acceleration of the combination was 3.26 m s-2 when braking on both axles (4 wheels). The deceleration of the combination was above 3.5 m s-2 under the condition of braking on both axles at the rated load of the agricultural trailer, while it was below the standard value in other braking approaches.