US Patent 7481204 Internal combustion engine flow regulating valve

A flow regulating valve for a diesel engine in which a unitary valve element has three positions for controlling flow from a unit injector fuel injection system in response to valve inlet pressure. The valve has a first position wherein flow is blocked below about 10 psi, a second position between about 10 psi and 20 psi wherein flow is substantially unrestricted, and a third position above about 20 psi wherein flow is restricted to minimize return flow to a fuel supply and minimize fuel cooling requirements.