Fuel pump system

A fuel pump system for injecting a fuel into a combustion chamber of an internal combustion engine has a pump (12) that can be actuated by a pump drive, which conveys fuel as a first injection fluid in a first fluid branch in the form of a fuel branch (14) from a first low-pressure connection (16) to a first high-pressure connection (18). The pump (12) is coupled with a displacement unit (20) that is fluidly connected to a second fluid branch (25), so that the pump (12) conveys a second injection fluid from a second low-pressure connection (42) to a second high-pressure connection (44) in the second fluid branch (25) via the displacement unit (20).