Akademik Veri Yönetim Sistemi
JOURNAL OF APPLIED FLUID MECHANICS, cilt.19, sa.7, ss.1806-1823, 2026 (SCI-Expanded, Scopus)
The Central Tire Inflation System (CTIS) is increasingly adopted in buses, trucks, and military vehicles, as it enables adaptive tire pressure control under varying terrain conditions, thereby improving vehicle performance and safety. In defense applications, the use of electronic components within tire systems is prohibited, which necessitates fully mechanical valve designs operating on alternative physical principles. This study presents an experimental and numerical investigation of a dynamic-function vehicle tire air control valve developed by Altan Hydraulic. Experimental results show that the original valve configuration cannot reliably remain open at low airflow rates (<= 135 L/min). To overcome this limitation, a vacuum-assisted operating mechanism was investigated. Region A denotes the vacuum chamber, Region B the highpressure chamber generating the opening force on the spool, and Region C the main flow passage. The nozzle tip inclination angle was modified from its original value of alpha = 90 degrees in 10 degrees increments over a range of 40 degrees-180 degrees, and the & Oslash;0.2 mm orifice was repositioned to align with regions of maximum flow velocity, limiting the mass flow entering Region A. Flow dynamics and spool force balances were analyzed for Reynolds numbers between 33,874 and 112,913. The redesigned configuration generated a vacuum pressure of approximately-35 kPa in Region A at alpha = 120 degrees, enabling the valve to remain open at tire pressures as low as 30 kPa. The results demonstrate that pressurized air from the tire can be used to generate a self-induced vacuum, ensuring sustained valve opening without electronic components. The proposed fully mechanical design significantly enhances CTIS performance by providing a reliable and energy-efficient solution for military and off-road vehicles.