# US 8,739,746 B2 · Variable oil pump diagnostic > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,739,746 B2 - Document ID: US8739746B2 - Status: Granted - Kind: B2 - Application number: 13/362,908 - Filed: 2012-01-31 - Published: 2013-08-01 - Granted: 2014-06-03 - Earliest claimed: 2012-01-31 - Assignees: Ford Global Technologies, LLC - Applicants: David Karl Bidner; John Eric Rollinger; John Smiley; Ed Badillo - Inventors: David Karl Bidner; John Eric Rollinger; John Smiley; Ed Badillo - Web page: https://patentgrep.com/patent/US8739746B2 ## CPC - F01M 1/08: Lubricating systems characterised by the provision therein of lubricant jetting means - F01M 11/10: Indicating devices; Other safety devices - F01M 1/16: Controlling lubricant pressure or quantity (rendering machines or engines inoperative or idling on lubricant pressure failure F01M1/22) - G01M 15/09: by monitoring pressure in fluid ducts, e.g. in lubrication or cooling parts - F01M: LUBRICATING OF MACHINES OR ENGINES IN GENERAL; LUBRICATING INTERNAL COMBUSTION ENGINES; CRANKCASE VENTILATING - G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR ## Abstract Embodiments for indicating degradation of a piston-cooling jet system are provided. In one example, an engine method comprises indicating degradation of a piston-cooling jet system in response to a relationship between engine speed and oil pressure at maximum oil pump displacement conditions. In this way, engine operation may be adjusted in response to an indicated degradation. ## Claims ### Claim 1 An engine method, comprising: during a first condition, pumping engine oil at less-than-maximum oil pump displacement to one or more components of an engine; during a second condition including unregulated oil pressure where the oil pressure does not undergo a commanded change in oil pressure, pumping engine oil at maximum oil pump displacement to the one or more components of the engine; and indicating degradation of a piston-cooling jet system during the second condition in response to a relationship between engine speed and oil pressure at the maximum oil pump displacement, wherein the relationship includes a responsive curve inflection point of the oil pressure, and wherein the response curve inflection point is determined responsive to the engine oil being pumped at maximum oil pump displacement. ### Claim 2 (depends on 1) The engine method of claim 1, wherein the inflection point indicates the oil pressure at which a check valve upstream of the piston-cooling jet opens, and wherein the inflection point is determined by collecting multiple engine speed/oil pressure points across a range of engine speeds at maximum oil pump displacement. ### Claim 3 (depends on 1) The engine method of claim 1, wherein the first condition comprises engine temperature below a threshold temperature, and wherein the second condition comprises engine temperature above the threshold temperature. ### Claim 4 (depends on 1) The engine method of claim 1, wherein the relationship is determined when a change in variable camshaft timing is less than a threshold. ### Claim 5 (depends on 1) The engine method of claim 1, wherein indicating degradation of the piston-cooling jet system further comprises setting a diagnostic code for the piston-cooling jet degradation and notifying a vehicle operator. ### Claim 6 (depends on 1) The engine method of claim 1, further comprising, in response to the indication of degradation, lowering maximum available engine torque. ### Claim 7 (depends on 1) The engine method of claim 1, further comprising, in response to the indication of degradation, lowering an engine coolant temperature set point. ### Claim 8 An engine method, comprising: during a first condition, pumping engine oil at less-than-maximum oil pump displacement from a variable flow oil pump to one or more components of an engine; during a second condition, pumping engine oil at maximum oil pump displacement from the variable flow oil pump to the one or more components of the engine and determining an inflection point between engine speed and oil pressure representing an oil pressure at which a passive check valve of a piston-cooling jet system opens, the inflection point determined by collecting multiple engine speed/oil pressure points across a range of engine speeds from low engine speed to high engine speed; reducing engine oil output from the variable flow oil pump if the inflection point is below a first threshold, and increasing engine oil output from the variable flow oil pump if the inflection point is above a second threshold. ### Claim 9 (depends on 8) The engine method of claim 8, wherein the second condition comprises engine temperature being above a threshold, and wherein the first condition comprises engine temperature being below the threshold. ### Claim 10 (depends on 8) The engine method of claim 8, wherein the second condition comprises engine speed and load exceeding a threshold, and wherein the inflection point is not determined during the first condition. ### Claim 11 (depends on 8) The engine method of claim 8, further comprising, if the inflection point is above the second threshold and engine oil output is at maximum output, lowering maximum available engine torque and/or lowering a coolant temperature set point. ### Claim 12 An engine system, comprising: a variable flow oil pump; a piston cooling jet system including a passive preloaded spring check valve; and a controller including instructions to: when operating at less-than-maximum oil pump displacement, maintain desired oil pressure by feedback control of the oil pump; indicate degradation of the passive preloaded spring check valve in response to a change in an inflection point between engine speed and oil pressure at maximum oil pump displacement comprising unregulated oil pressure where the oil pressure does not undergo a commanded change, the inflection point determined by collecting multiple engine speed/oil pressure points across a range of engine speeds from low engine speed to high engine speed; and lower one or more of a maximum available engine torque and an engine coolant temperature set point in response to the indicated degradation. ### Claim 13 (depends on 12) The engine system of claim 12, wherein the change in the inflection point is determined during stable variable camshaft timing conditions. ### Claim 14 (depends on 12) The engine system of claim 12, wherein the change in the inflection point is determined during conditions where oil temperature is in a threshold range. ### Claim 15 (depends on 12) The engine system of claim 12, wherein a decrease in the inflection point indicates a decrease in a set point of the check valve, and in response to the decrease in the set point, decreasing oil pump output when engine temperature exceeds a threshold. ### Claim 16 (depends on 12) The engine system of claim 12, wherein an increase in the inflection point indicates an increase in a set point of the check valve, and in response to the increase in the set point, increasing oil pump output when engine temperature exceeds a threshold. ### Claim 17 (depends on 12) The engine system of claim 12, wherein the controller includes further instructions to, if a determined oil pressure at a given engine speed is lower than an expected oil pressure, indicate degradation of the variable flow oil pump.