Journal of Applied Sciences1812-56541812-5662Asian Network for Scientific Information10.3923/jas.2005.781.786MohtasebiS.S. A. Keyhani M. Rahimi 4200554In this study, the fuel pressure regulator for MPFI PAYKAN 1600 cc engine which is a diaphragm operated valve has been simulated, analyzed and tested. The fuel pressure regulator is usually mounted on the fuel rail to maintain a constant relative pressure (3.5 bar) between the fuel injector and the air intake manifold. The regulator is first described and analyzed based on its functionality. Then, the mathematical equations of various sections of the regulator are presented. After that and based on those equations, the mathematical model of whole system is derived. This model is solved and analyzed using MATLAB engineering software. The good agreement between simulation and experiment results provided confidence to use the mathematical model to find out the steady state and transient responses of the regulator at different operating conditions. Finally, to make the regulator less sensitive to parameter variations, the sensitivity analysis is also done.]]>Shin, Y.C.,1991133280288Handroos, H.M. and M.J. Vilenius,1992114707713Rahimi, M.,20022002Mohtasebi, S.S. and H. Hong,1999108766774Anonymous,1992Anonymous,1993Vilenius, M.J.,19831057782Nise, N.S.,1992