The pressure relief valve is located between the fuel filter and the high pressure pump. It is located in the connecting line between the inlet line before the HPP and the return line after the HPP.
Tasks:
The pressure relief valve performs the same task as a pressure limiting valve. It limits the inlet pressure to the high pressure pump from 2.0 to between 2.0 and 3.0 bar. This relieves excess pressure by diverting fuel into the return line.
It protects the high pressure pump and the auxiliary delivery pump from overloads.
Effect in the case of fault:
• Excessive pressure reduces the service life of the auxiliary delivery pump
• The hydrodynamic noises in the HPP and the auxiliary delivery pump rise
• This could force the shaft seal out of the HPP
