# US 8,149,004 B2 · Corrosion sensor for monitoring and controlling lubricant acidity > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,149,004 B2 - Document ID: US8149004B2 - Status: Granted - Kind: B2 - Application number: 11/655,271 - Filed: 2007-01-19 - Published: 2008-07-24 - Granted: 2012-04-03 - Earliest claimed: 2007-01-19 - Assignees: Honeywell International Inc. - Inventors: Raghurama A. Raju; Sanjeeb Tripathy; Jicang Zhou - Web page: https://patentgrep.com/patent/US8149004B2 ## CPC - G01N 17/02: Electrochemical measuring systems for weathering, corrosion or corrosion-protection measurement - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract A corrosion sensor having a corrodible element that is corrodible in a lubricant or hydraulic oil, wherein the corrosion sensor is adapted to monitor degradation of the lubricant or hydraulic oil is disclosed. ## Claims ### Claim 1 An apparatus comprising: a corrosion sensor comprising a metal-containing corrodible element which is corrodible in a lubricant having an acidity level, wherein the acidity level is a measure of lubricant degradation and the corrosion sensor is configured to measure lubricant degradation in real time, wherein, in response to increasing corrosion, the metal-containing corrodible element is configured to release metal ions into the lubricant to control the acidity level, further wherein the increasing corrosion is associated with increasing resistance of the metal-containing corrodible element, wherein the corrosion sensor further comprises a reference corrodible element having a corrosion level of substantially zero; and an output device coupled to the corrosion sensor to display information related to the acidity level, the information based on the increasing resistance of the metal-containing corrodible element. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the metal-containing corrodible element comprises a metal plate, metal foil, a metal wire, or a metal oxide film. ### Claim 3 (depends on 2) The apparatus of claim 2, wherein the metal plate, metal foil, metal wire, or metal oxide film comprises an element selected from K, Na, Ba, Mg, Al, Zn, Fe, Ni, Sn, Pb, Cu, Ag and combinations thereof. ### Claim 4 (depends on 2) The apparatus of claim 2, wherein the metal is a metal alloy and the wire has a thickness and diameter in a range of about 1 nm to about 1 mm. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the reference corrodible element is located in a vacuum airlock chamber or a small hermetically sealed non-metallic enclosure. ### Claim 6 (depends on 1) The apparatus of claim 1 wherein the corrosion sensor is located in an engine containing the lubricant. ### Claim 7 (depends on 6) The apparatus of claim 6 wherein the engine is located in a vehicle and the information includes a recommendation to replace the lubricant. ### Claim 8 (depends on 1) The apparatus of claim 1 wherein the corrosion sensor is a one-time use corrosion sensor. ### Claim 9 (depends on 1) The apparatus of claim 1 wherein the corrosion sensor is a conformable corrosion sensor. ### Claim 10 A system comprising: a corrosion sensor comprising a metal-containing corrodible element which is corrodible in a lubricant having an acidity level, wherein the acidity level is a measure of lubricant degradation and the corrosion sensor is configured to measure lubricant degradation in real time, wherein, in response to increasing corrosion, the metal-containing corrodible element is configured to release metal ions into the lubricant to control the acidity level, further wherein the increasing corrosion is associated with increasing resistance of the metal-containing corrodible element, wherein the corrosion sensor further comprises a reference corrodible element having a corrosion level of substantially zero; an electronic module connected to the corrosion sensor for receiving and analyzing data from the corrosion sensor, including data about the acidity level; and an output device coupled to the electronic module to display information related to the acidity level, the information based on the increasing resistance of the metal-containing corrodible element. ### Claim 11 (depends on 10) The system of claim 10, wherein the corrosion sensor is located in an engine containing the lubricant. ### Claim 12 (depends on 10) The system of claim 10, wherein the metal-containing corrodible element comprises a metal plate, metal foil, a metal wire, or a metal oxide film. ### Claim 13 (depends on 12) The system of claim 12, wherein the metal plate, metal foil, metal wire, or metal oxide film comprises an element selected from K, Na, Ba, Mg, Al, Zn, Fe, Ni, Sn, Pb, Cu, Ag and combinations thereof. ### Claim 14 (depends on 10) The system of claim 10, wherein the corrodible element comprises Cu. ### Claim 15 (depends on 10) The system of claim 10, wherein the reference corrodible element is located in a vacuum airlock chamber or a small hermetically sealed non-metallic enclosure. ### Claim 16 (depends on 15) The system of claim 15, further comprising wherein the reference corrodible element provides automatic temperature compensation of the metal-containing corrodible element. ### Claim 17 (depends on 10) The system of claim 10, wherein the reference corrodible element is a sealed reference corrodible element located in a hermetically sealed non-metallic enclosure, and the electronic module is capable of comparing an amount of corrosion of the metal-containing corrodible element with respect to the sealed corrodible element. ### Claim 18 (depends on 10) The system of claim 10 wherein the corrosion sensor is located in an engine containing the lubricant. ### Claim 19 (depends on 18) The system of claim 18 wherein the engine is located in a vehicle. ### Claim 20 (depends on 10) The system of claim 10 wherein the acidity level is a maximum acidity level. ### Claim 21 A method comprising: with a corrosion sensor having a metal-containing corrodible element, sensing data pertaining to acidity of a lubricant, wherein the acidity level is a measure of lubricant degradation and the corrosion sensor is configured to measure lubricant degradation in real time; allowing the corrodible element to corrode, wherein, in response to increasing corrosion, the metal-containing corrodible element releases metal ions into the lubricant to control the acidity level, wherein the increasing corrosion is associated with increasing resistance of the metal-containing corrodible element; comparing an amount of corrosion with a reference corrodible element in communication with the corrosion sensor and having a corrosion level of substantially zero; determining an acidity level with the corrosion sensor; and providing acidity level data sensed by the corrosion sensor to an electronic module, the data based on the increasing resistance of the metal-containing corrodible element. ### Claim 22 (depends on 21) The method of claim 21, further comprising determining a rate at which the corrodible element is corroded. ### Claim 23 (depends on 22) The method of claim 22, wherein the step is performed by applying a voltage difference between two locations of the corrodible element. ### Claim 24 (depends on 22) The method of claim 22, wherein the determining step comprises measuring a potential which corresponds to a polarization of the corrodible element and measuring a current flowing through the corrodible element, wherein the polarization and the measured current output together indicate an amount of corrosion of the corrodible element. ### Claim 25 (depends on 22) The method of claim 22, wherein the reference corrodible element is a sealed reference corrodible element which located in a hermetically sealed non-metallic enclosure, wherein corrosion of the reference corrodible element is substantially zero. ### Claim 26 (depends on 22) The method of claim 22, wherein the determining step is performed by optical microscopy. ### Claim 27 (depends on 21) The method of claim 21, wherein the determining step is performed by electrochemical impedance spectroscopy. ### Claim 28 (depends on 21) The method of claim 21 wherein the acidity level is a maximum acidity level. ### Claim 29 (depends on 21) The method of claim 21 wherein the metal-containing corrodible element undergoes a polarization change from a level near substantially zero corrosion to values approaching a maximum potential.