http://www.iaeme.com/IJMET/index.asp 1128 editor@iaeme.com International Journal of Mechanical Engineering and Technology (IJMET) Volume 9, Issue 13, December 2018, pp. 1128–1139, Article ID: IJMET_09_13_118 Available online at http://www.iaeme.com/ijmet/issues.asp?JType=IJMET&VType=9&IType=13 ISSN Print: 0976-6340 and ISSN Online: 0976-6359 © IAEME Publication Scopus Indexed PERFORMANCE ANALYSIS OF THE HYDRO- PNEUMATIC SUSPENSION SYSTEM OF HEAVY TRUCK Le Xuan Long Faculty of Automotive and Power Machinery Engineering, Thai Nguyen University of Technology, Thai Nguyen, Vietnam Tran Thi Hong Center of Excellence for Automation and Precision Mechanical Engineering, Nguyen Tat Thanh University, Ho Chi Minh City, Vietnam Le Van Quynh Faculty of Automotive and Power Machinery Engineering, Thai Nguyen University of Technology, Thai Nguyen, Vietnam Bui Van Cuong Faculty of Automotive and Power Machinery Engineering, Thai Nguyen University of Technology, Thai Nguyen, Vietnam *Corresponding Author E-mail: lequynhdl@yahoo.com ABSTRACT The purpose of this paper is to analyze the performance of the hydro-pneumatic suspension system of heavy truck on the ride quality of road surfaces. A full dynamic model of a heavy vehicle equipped with three different suspension systems is established to evaluate the effect of suspension characteristics on dynamic load coefficient (DLC). A Matlab Simulink model of fifteen degrees of freedom (DOF) full vehicle model is set up to solve the differential equations describing the vertical motion. The performance of the hydro-pneumatic suspension system compared to the rubber and air spring suspension systems is analyzed when vehicle operates under the different conditions such as road surface roughness, vehicle speeds, vehicle loads. The obtained results indicated that, for the hydro-pneumatic suspension system, the values of DLC at 3rd axle of vehicle are reduced by 388.9 %, 392.4 %, 381.2 %, 355.6 %, and 410.6%, respectively in comparison with the rubber suspension system with the different road conditions and significantly reduced by 313.9%, 550.1%, 381.8%, 369%, 407.3% and 427% at the vehicle speed conditions, which reduces more the negative impact on road surface in comparing to the rubber suspension system. Vehicle's stability and control of the steering system with the hydro-pneumatic suspension system are much better than the air suspension system and especially when vehicle operates under the off-road conditions.