Internal combustion engine with a fuel supply system

The engine (12) has a fuel supply device with fuel pump (34), fuel pressure damper (36) and injection valve (26). The pressure damper has damper membrane (54) that separates the damper chamber (53) and damper back chamber (56) from each other. The damper back chamber is loaded with first reference pressure. The pressure of fuel supplied by the fuel pump to injection valve is regulated by fuel pressure regulator (35) based on the second reference pressure of pressure regulator. The first reference pressure and second reference pressure are adjusted relative to each other.