Patent ID: 7444977

Claim:
A method of reducing fuel consumption in a diesel engine the method comprising the steps of: obtaining system oil from said diesel engine when said diesel engine is operating at less than full power, said obtained system oil having a first viscosity parameter and a first temperature; passing at least some amount of the obtained system oil to a viscosity regulating device; bypassing a remaining amount of obtained system oil to an oil cooler; wherein the step of bypassing is done on the basis of at least one parameter representing an actual load of the engine and the first viscosity parameter of the obtained system oil; combining the bypassed system oil and the passed system oil to thereby create modified system oil, said modified system oil having a second viscosity parameter and a second temperature, wherein said second viscosity parameter is less than said first viscosity parameter and said second temperature is higher than said first temperature; and providing said modified system oil to said diesel engine.