FUEL PUMP

Fuel pump (10), in particular a high-pressure fuel pump of a common-rail fuel system, with a pump piston (13) guided in a pump cylinder (11), wherein in the region of a recess (12) of the pump cylinder (11), in which the pump piston (13) is guided, an upper inlet groove (17) coupled via at least one inlet bore (20) to a first pressure level and a lower outlet groove (19) coupled via at least one outlet bore (22) to a second pressure level for fuel serving lubrication and optionally cooling is formed, wherein in the region of the recess (12) of the pump cylinder (11) between the upper inlet groove (17) and the lower outlet groove (19) a further, middle inlet groove (18) is formed, which is coupled via at least one inlet bore (21) to the first pressure level, wherein between an upper edge (23) of the lower outlet groove (19) and a lower edge (24) of the middle inlet groove (18) a first guide land (25) for the pump piston (13) and between an upper edge (26) of the middle inlet groove (18) and a lower edge (27) of the upper inlet groove (17) a second guide land (28) for the pump piston (13) is formed.