The main objective of this article is to analyse the flow characteristics of a proportional flow control valve and to improve its characteristics by means of geometrical modifications of the valve spool. As the first step, a geometrical model of the valve was built in a CAD system and flow analyses were carried out using CFD methods. Two types of openings in the spool were tested: a round and a triangular one. Simulations were conducted with various values of throttle gap width, flow rate and input pressure. Based on the obtained results, the jet angle was determined as a function of throttle gap width for both types of openings. Then, a mathematical model of the valve was formulated. Based on the mathematical model, a simulation model was built in Matlab/Simulink. The results of the simulation results showed that the use of triangular openings in a throttle valve spool instead of standard round openings increased the proportional operating range of the valve by approximately 40%. The obtained simulation results were verified experimentally on a test bench. (C) 2016 Elsevier Ltd. All rights reserved.