with the primary flow alone and with the primary flow and secondary flow respectively the injector in fig1 and 2 comprises a cylindrical outer bushing 1 which is hollowed out in places between its two end faces it contains at the upstream end a strainer type fuel filter 2 and opens via a fuel inlet orifice 3 the fuel filter 2 bears against a diaphragm 4 with a central orifice 5 which is designed to regulate the flow of fuel in the face of size variations produced during manufacture according to the teaching of french patent 2 832 492 already cited at the start of this text a bearing seat 6 for a primary valve 7 extends further downstream in the outer bushing 1 a weak spring 28 biases the primary valve 7 against the seat 6 towards the upstream end of the injector when the force of the spring 8 is overcome by the pressure of the fuel the primary valve 7 moves downstream and allows the fuel to pass around it the outer bushing 1 also comprises an inner body 8 with a piercing 9 in which there slides a secondary valve 10 which is biased by a spring 11 towards the upstream end as far as a stop position which can be produced by a collar 12 of the secondary valve 10 which is located at the downstream end.