the drawing shows a suction jet pump of the invention in section . the suction jet pump has a drive line 1 , which discharges via a jet outlet 2 into an intake chamber 3 . the jet outlet 2 is for instance embodied as narrowed in nozzlelike form . a mixing conduit 4 is disposed on the intake chamber 3 , in an imaginary extension of the jet outlet 2 , in such a way that a fluid stream emerging from the jet outlet 2 of the drive line 1 reaches the inside of the mixing conduit 4 in a straight line via the intake chamber 3 . the cross sections of the jet outlet 2 and mixing conduit 4 therefore overlap in projection . the mode of operation of a suction jet pump is well known , so that it will be described only briefly here : via the drive line 1 and its jet outlet 2 , a driving flow is introduced in streamlike form into the intake chamber 3 . the driving flow is an arbitrary liquid , but in principle it could also be a gas . the driving stream of the drive line 1 carries surrounding fluid from the intake chamber 3 along with it into the mixing conduit 4 . as a result , an underpressure is created in the intake chamber 3 , which causes replenishing fluid to flow out of the surroundings of the suction jet pump into the intake chamber 3 , via an intake opening 5 of the intake chamber 3 . a valve member 6 is provided at the intake opening 5 and cooperates with the intake opening 5 and with it forms a check valve . the valve member 6 in this embodiment is embodied in umbrella - like form but may also be embodied in arbitrary other ways , such as t - shaped , double - t - shaped , conical , spherical , disklike , or cylindrical . the valve member 6 may be embodied as elastic or rigid . according to the invention , it is provided that the drive line 1 has a bypass opening 10 , which discharges into the intake chamber 3 and is disposed such that its bypass flow acts indirectly or directly on the valve member 6 . the bypass flow acts on the valve member 6 in a closing manner , that is , counter to the opening direction of the check valve . for instance , the bypass opening 10 is aimed at the valve member 6 in such a way that the stream or flow of the bypass opening 10 strikes the valve member 6 . it is at least provided that the volumetric flow of the bypass opening 10 spills over the valve member 6 and in the process exerts flow forces thereon . the bypass opening 10 is designed and disposed such that its bypass flow exerts such a strong force on the valve member 6 that the valve member 6 is movable in the direction of its valve seat . the bypass opening 10 may be embodied such that the valve member 6 can be closed completely by means of the bypass flow of the bypass opening 10 . the diameter of the bypass opening 10 must be smaller than that of the jet outlet 2 of the drive line 1 . in this way , an additional flow resistance , directly dependent on the driving flow , is generated at the intake opening 5 and increasingly lessens the increase in suction power as the driving flow increases . as a result , the characteristic curve of the suction jet pump , representing the volumetric flow aspirated via the intake opening 5 as a function of the driving flow , has a shallower course than in the prior art . hence the suction jet pump can be designed such that its suction power in the desired driving flow region is above the minimum power and below the critical foam limit . as a result of the embodiment according to the invention , foaming downstream of the mixing conduit 4 from aspiration of air is avoided or at least reduced . a self - regulating suction jet pump is achieved . with a portion 1 . 1 , the drive line 1 extends into the intake chamber 3 , and the bypass opening 10 is located in the portion 1 . 1 . a portion 1 . 2 , angled relative to the portion 1 . 1 , is for instance embodied upstream of the portion 1 . 1 , and the bypass opening 10 is disposed for instance in the vicinity of the angle between the two portions . the bypass opening 10 is embodied for instance on the underside of the portion 1 . 1 , oriented toward the bottom 14 . the intake opening 5 is provided on the bottom 14 , in the region below the bypass opening 10 . the bypass opening 10 has an axis 10 . 1 , which is aligned parallel with the intake opening 5 and the valve member 6 and can extend either perpendicular or obliquely relative to the bottom 14 of the storage tank . the axis 10 . 1 may be aligned with the axis of the intake opening 5 . however , the intake opening 5 may also be offset from the bypass opening 10 , as depicted in fig1 . in the embodiment in fig1 , the suction jet pump is provided in a cup - shaped storage tank 11 , which is disposed in a fuel supply tank 12 . the intake chamber 3 of the suction jet pump is embodied as open on one end , for instance , and rests with the open end on a bottom 14 of the storage tank 11 , as a result of which the open end of the intake chamber 3 is closed . the intake opening 5 of the intake chamber 3 , in the exemplary embodiment , is provided on the bottom 14 of the storage tank 11 but could also be embodied on the housing of the suction jet pump . the check valve formed by the intake opening 5 and the valve member 6 prevents a return flow of liquid from the storage tank 11 back into the fuel supply tank 12 via the mixing conduit 4 and the intake chamber 3 . the mixing conduit 4 extends for instance horizontally in the direction of the bottom 14 of the storage tank 11 . in the suction jet pump of the invention , some of the driving flow flows via the jet outlet 2 , and a remaining portion of the driving flow via the bypass opening 10 into the intake chamber 3 . the portion flowing via the bypass opening 10 generates an additional flow resistance or pressure loss at the check valve , the value of which is dependent on the driving quantity . the greater the driving flow , the greater the pressure loss that is generated . in the intake chamber 3 , the bypass flow of the bypass opening 10 is aspirated and flows , like the aspirated flow that is aspirated via the intake opening 5 , along with the flow of the driving stream into the storage tank 11 via the mixing conduit 4 . the suction jet pump according to the invention shown in fig1 may be employed for instance in an apparatus for delivering fuel . this apparatus has for instance a delivery unit 16 , which aspirates fuel from the storage tank 11 and delivers it , at increased pressure , via a pressure line 17 to an internal combustion engine 18 . the drive line 1 branches off from the pressure line 17 , and a pressure - regulating valve 19 may be provided , which only beyond a predetermined pressure allows fuel to flow out of the pressure line 17 into the drive line 1 . the storage tank 11 keeps enough fuel in reserve for the delivery unit 16 that the delivery unit can aspirate fuel even at low levels in the fuel supply tank 12 and upon acceleration , braking , cornering , and / or climbing hills . by means of the suction jet pump of the invention , a partial evacuation of the storage tank 11 from aspiration of air and attendant foaming is avoided . the foregoing relates to the preferred exemplary embodiment of the invention , it being understood that other variants and embodiments thereof are possible within the spirit and scope of the invention , the latter being defined by the appended claims .