# US 2020/0400050 A1 · Crankcase ventilation system and diagnostic method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0400050 A1 - Document ID: US20200400050A1 - Status: Published application - Kind: A1 - Application number: 16/450,886 - Filed: 2019-06-24 - Published: 2020-12-24 - Earliest claimed: 2019-06-24 - Assignees: Ford Global Technologies, LLC - Applicants: Ford Global Technologies, LLC - Inventors: Robert Roy Jentz; Matthew Carpenter; Michael Stephen Sweppy - Web page: https://patentgrep.com/patent/US20200400050A1 ## CPC - F02M 25/06: adding lubricant vapours - F01M 1/10: Lubricating systems characterised by the provision therein of lubricant venting or purifying means, e.g. of filters - F01M 1/20: concerning lubricant pressure - F01M 13/00: Crankcase ventilating or breathing - F01M 13/0011: {Breather valves} - F01M 13/04: having means for purifying air before leaving crankcase, e.g. removing oil - G01M 3/025: {Details with respect to the testing of engines or engine parts} - F01M 2013/0083: {Crankcase pressure} - F01M 2250/00: Measuring - Y02T 10/12: Improving ICE efficiencies - F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF - 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 - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract Methods and systems are provided for diagnosing a positive crankcase ventilation (PCV) system. In one example, a PCV system diagnostic method is provided that includes a determining a fault condition in a positive crankcase ventilation (PCV) system by comparing a pressure sampled from a pressure sensor positioned on a clean side of an oil separator coupled to a crankcase with a modeled pressure representing an expected pressure on the clean side of the oil separator. ## Claims ### Claim 1 A method comprising: determining a fault condition in a positive crankcase ventilation (PCV) system by comparing a pressure sampled from a pressure sensor positioned on a clean side of an oil separator coupled to a crankcase with a modeled pressure representing an expected pressure on the clean side of the oil separator, where the clean side of the oil separator is coupled to an intake conduit of an engine upstream of an intake throttle via a ventilation line. ### Claim 2 (depends on 1) The method of claim 1, where the fault condition is a PCV ventilation line leak. ### Claim 3 (depends on 1) The method of claim 1, where the fault condition is a malfunction of the pressure sensor. ### Claim 4 (depends on 1) The method of claim 1, where determining the fault condition includes determining if the comparison between the sampled pressure and the modeled pressure is outside a dynamic tolerance band. ### Claim 5 (depends on 1) The method of claim 1, where the modeled pressure is determined based on a cylinder blow-by value and an airflow through a PCV valve into the crankcase from an intake manifold. ### Claim 6 (depends on 1) The method of claim 1, further comprising implementing a mitigating action in the PCV system in response to determining the fault condition. ### Claim 7 (depends on 1) The method of claim 1, further comprising setting a diagnostic code, and/or notifying a vehicle operator of the fault condition in response to determining the fault condition. ### Claim 8 A positive crankcase ventilation (PCV) system in an engine comprising: a crankcase including an interior chamber; an oil separator coupled to the crankcase; a PCV valve positioned in a PCV line coupled to the crankcase and an intake manifold in an intake system; a pressure sensor positioned on a clean side of the oil separator and spaced away from an end of a ventilation line, where the oil separator is coupled to the crankcase; and a controller including instructions stored in non-transitory memory that when executed cause the controller to: determine a fault condition in the PCV system by comparing a pressure sampled from the pressure sensor with a modeled pressure representing an expected pressure on the clean side of the oil separator. ### Claim 9 (depends on 8) The PCV system of claim 8, where the ventilation line is coupled to the oil separator and an intake conduit arranged upstream of a compressor and where the intake manifold is arranged downstream of the compressor. ### Claim 10 (depends on 9) The PCV system of claim 9, where the fault condition is a ventilation line leak and/or a pressure sensor malfunction. ### Claim 11 (depends on 9) The PCV system of claim 9, where determining the fault condition includes determining if the comparison between the sampled pressure and the modeled pressure is outside a tolerance band. ### Claim 12 (depends on 11) The PCV system of claim 11, where the tolerance band is dynamic and increases during engine transients and decrease during steady state conditions of the engine. ### Claim 13 (depends on 9) The PCV system of claim 9, where the modeled pressure is determined based on a cylinder blow-by value and an airflow through a PCV valve into the crankcase from the intake manifold. ### Claim 14 (depends on 9) The PCV system of claim 9, where the fault condition is determined responsive to an accumulated air flow through the intake system surpassing a threshold value. ### Claim 15 (depends on 9) The PCV system of claim 9, where the fault condition is determined responsive to the intake manifold pressure surpassing a threshold value indicating a boost condition. ### Claim 16 A method for operating a positive crankcase ventilation (PCV) system in an engine comprising: sampling a pressure sensor positioned on a clean side of an oil separator coupled to a crankcase to determine a measured pressure, the oil separator coupled to an intake passage of the engine via a ventilation line; generating a modeled pressure representing an expected pressure on the clean side of the oil separator; comparing the measured pressure with the modeled pressure; and determining a fault condition based on the comparison between the measured pressure and the modeled pressure. ### Claim 17 (depends on 16) The method of claim 16, where the fault condition is a ventilation line leak and/or a pressure sensor malfunction. ### Claim 18 (depends on 16) The method of claim 16, where the modeled pressure is determined based on a cylinder blow-by value and an airflow through a PCV valve into the crankcase from an intake manifold. ### Claim 19 (depends on 16) The method of claim 16, where determining the fault condition includes determining if the comparison between the sampled pressure and the modeled pressure is outside a tolerance band. ### Claim 20 (depends on 19) The method of claim 19, where the tolerance band is dynamic and increases during engine transients and decrease during steady state conditions of the engine.