Prof. Dr. Ataur Rahman, Mr Mohammad Amysar,
Volume 8, Issue 2 (6-2018)
Abstract
ABSTRACT: Deceleration or stopping the vehicle without any diving and lateral acceleration is essential to develop an effective braking system. The hydraulic braking system with intelligent braking called Antilock Braking system (ABS) and Electronic Stability Control (ESC) has been introduced. However, due to the insufficient human effort, the ABS and ESC to some extent, not function well. This has been emphasised to develop a DC motor assist hydraulic braking system by associating the wheel speed and engine fuel flow sensor to stop the vehicle in required braking distance without any diving and lateral movement. This study investigates theoretically by Solid work simulation model and experimentally by product development. The simulation model has shown that a full load passenger car needs 15.7Mpa of braking pressure to stop 50km/h vehicle in 10m. The experimental results of the model show that the pressure develops when the pedal fully applied without and with aids of the DC motor is 910 kPa and 1130 kPa respectively, which contribute to 23.3% of pressure increase.
KEYWORDS: DC motor assist hydraulic braking system; Digital Control System; Braking efficiency.
Mahdi Ajami, Hossein Jannat, Masoud Masih-Tehrani,
Volume 10, Issue 4 (12-2020)
Abstract
Braking test is one of the most important tests of a mechanized technical inspection line. In this study, the effect of tire pressure changes on the accuracy of the braking test results is investigated at technical inspection centers. This study is conducted in three stages. In the first step, the braking efficiency at different tire pressures is examined using a roller brake tester. In the second step, the tests at different pressures and velocities on the road are done. These tests are carried out in terms of stopping distance, to ensure the accuracy and reliability of the first step test results. The results of the first and second steps showed that the effect of tire pressure changes on the braking efficiency is significant. In the third step, the braking test results of a thousand vehicles that received technical inspection certificate are studied. Analysis of these results, considering the results of the first and second steps cleared that about 16% of vehicles that received technical inspection certificate have lower braking efficiency than the minimum acceptable efficiency. The obtained results specified the necessity of adjusting the pressure of tires before the braking test at vehicle technical inspection centers in Iran.
