Abstract: An electrically-actuated liquid spraying system for controlling the volumetric flow through pressure-atomization spray nozzles is disclosed. Each nozzle is attached to a direct acting, in-line solenoid valve which is connected to a liquid supply at constant pressure. The valve is excited by square wave pulses of variable frequency and duty cycle to reciprocate between its fully open and closed positions and thereby control the flowrate over a range without changing droplet size and spray pattern. The frequency and duty cycle of the square wave pulses are varied and controlled by feedback data of relative target movement, size, shape and other factors as well as by gated sampling of the dynamic pressure in a region between the valve seat and nozzle orifice.