An injection system for an internal combustion engine

Described herein is a fuel-injection system (1,1',1",1"') for an internal-combustion engine (2), of the type provided with: a tank (3) for collection of the fuel; compressor means (4) for drawing in said fuel from said tank (3) and making it available at high pressure to a storage volume (7); at least one injector (8,8',8''') fluidically connected to said storage volume (7) for taking in said fuel at a high pressure from said storage volume (7) and injecting it into a respective combustion chamber (12) of said engine (2); a fluid line (17) connecting said storage volume to said tank; and pressure-regulator means (19) in said storage volume (7) set along said fluid line (17); said pressure-regulator means (19) are set fluidically downstream of said storage volume (7) so as to enable a continuous flow of fuel through the storage volume (7) itself.