System and method for determining oil quality

#The present invention relates to determining the quality of oil used in a machine or apparatus.

#Oil is used in numerous applications and is commonly used as a lubricant in engines. Due to the broad range of engines and operating environments, lubrication oil is available in a variety of different viscosities (formulations, weights, or grades). For example, lubrication oil could be a single viscosity oil, such as SAE 30 base oil, which has a viscosity of 30 at a set testing temperature or lubrication oil could be a multi-viscosity oil, such as 15W40, 0W30, or 10W30. With multi-viscosity oils, the first number indicates a first viscosity at a first temperature (a cold temp.) and the second number indicates the oil's second viscosity at a second temperature (a hot temp.) Multi-viscosity oils are beneficial in engine use to help handle the diverse operating environments, such as cold start.

#In some devices or engine systems, lubrication oil is also used as an actuation fluid for hydraulically actuated devices. For example, because lubrication oil is a common fluid source in engine systems, it is relatively easy to employ for hydraulic “muscle” in hydraulically actuated electronically controlled unit injectors or hydraulically actuated or partially actuated valves. By using hydraulic power, actuation events can be controlled independently of the engine speed (eliminating dependency on the cam shaft) and enhance engine performance. Specifically, in unit injectors, oil is pressurized to relatively high levels and is used in conjunction with an intensifier piston to pressurize fuel to injection pressure. With valves, the pressurized oil can be used to open intake or exhaust valves.

#FIG. 1 is a schematic illustration of a fuel system according to one embodiment of the present invention.

#FIG. 1 illustrates an embodiment of a hydraulically actuated electronically controlled fuel injection system 110 in an example configuration as adapted for a direct-injection diesel-cycle internal combustion engine 112. Fuel system 110 includes one or more hydraulically-actuated electronically-controlled fuel injectors 114, positioned in a respective cylinder head bore (not shown) of engine 112. Fuel system 110 includes a first source of pressurized fluid flow 116 for supply of actuating fluid to each injector 114, a second source of pressurized fluid flow 118 for supplying fuel to each injector, a computer 120 for electronically controlling the fuel injection system and an apparatus 122 for re-circulating actuation fluid leaving each of the injectors.

#The first fluid source 116 preferably includes an actuating fluid sump 124, a relatively low pressure actuating fluid transfer pump 126, an actuating fluid cooler 128, one or more actuation fluid filters 130, a high pressure pump 132 for generating relatively high pressure in the actuation fluid and at least one relatively high pressure actuation fluid manifold 136. A oil rail passage 138 is arranged in fluid communication with the outlet from the relatively high pressure actuation fluid pump 132. A rail branch passage 140 connects the actuation fluid inlet of each injector 114 to the high pressure oil rail passage 138.

#Actuation fluid leaving an actuation fluid drain of each injector 114 enters a re-circulation line 127 that carries the same to the actuation fluid re-circulating apparatus 122. A portion of the re-circulated actuation fluid is channeled to high pressure actuation fluid pump 132 and another portion is returned to actuation fluid sump 124 via re-circulation line 133.