Patent ID: 7954477

Claim:
Diesel cycle internal combustion engine to be operated with a variety of fuels having different boiling points and different viscosity-temperature characteristic curves, with a fuel circuit for circulating a predetermined fuel, the fuel circuit comprising a fuel tank, a fuel pump, a fuel line, a high-pressure pump, a primary fuel filter located between the fuel pump and the high-pressure pump and having a pressure relief valve that accuates at a predetermined pressure to divert fuel to an intake side of the fuel pump, an injection system and a return line to return fuel to the fuel tank, and further comprising a control valve in the return line for dividing a fuel flow of the predetermined fuel to the fuel tank and/or to the fuel pump, wherein the division is undertaken as a function of the viscosity of the predetermined fuel and wherein the control valve comprises a pressure relief valve to divert said predetermined fuel of a predetermined higher viscosity to the intake side of the fuel pump, and a throttling device to divert said predetermined fuel of a predetermined lower viscosity back to the fuel tank.