PUMP UNIT FOR FEEDING FUEL, PREFERABLY DIESEL FUEL, TO AN INTERNAL COMBUSTION ENGINE

The invention relates to a pump unit for feeding fuel, preferably diesel fuel, to an internal combustion engine, comprising at least one cylinder (), a piston () which is displaceably arranged in the cylinder (), and a pressure valve () for selectively controlling the supply of fuel to the internal combustion engine, wherein the pressure valve () has a closure part () provided with a cavity () that opens to the outside on an end surface () facing the piston () of the closure part ().