# US 9,435,251 B2 · Method for estimating charge air cooler condensation storage and/or release with an intake oxygen sensor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,435,251 B2 - Document ID: US9435251B2 - Status: Granted - Kind: B2 - Application number: 13/967,968 - Filed: 2013-08-15 - Published: 2015-02-19 - Granted: 2016-09-06 - Earliest claimed: 2013-08-15 - Assignees: Ford Global Technologies, LLC - Applicants: Ford Global Technologies, LLC - Inventors: Gopichandra Surnilla; Dan A. Makled; Richard E. Soltis - Web page: https://patentgrep.com/patent/US9435251B2 ## CPC - F02D 41/1456: {with sensor output signal being linear or quasi-linear with the concentration of oxygen} - F02B 29/04: Cooling of air intake supply - F02B 29/0468: {Water separation or drainage means} - F02D 41/0007: {for control of turbo-charged or super-charged engines (control of the pumps per se F02B37/12)} - F02D 41/222: {relating to the failure of sensors or parameter detection devices} - F02M 35/10393: {for characterising a multi-component mixture, e.g. for the composition such as humidity, density or viscosity} - F02P 5/1502: {using one central computing unit} - F02D 2200/0418: Air humidity - Y02T 10/12: Improving ICE efficiencies - F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W) - F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G) - F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF - F02P: IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES ({anti-pollution means for internal-combustion engines F02B17/00}; specially adapted for rotary-piston or oscillating-piston engines F02B53/12; {ignition of gas turbine plants F02C7/26; ignition of jet propulsion plants F02K9/95; starting of combustion engines F02N9/00}; ignition of combustion apparatus in general, glowing plugs F23Q; measuring of physical variables in general G01; controlling in general G05; data processing in general G06; electrical components in general see Section H; {ignition coils H01F38/12}; sparking plugs H01T13/00) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract Methods and systems are provided for estimating water storage in a charge air cooler (CAC). In one example, an amount of water in charge air exiting the CAC may be based on an output of an oxygen sensor positioned downstream of the CAC. Further, engine actuators may be adjusted to increase combustion stability and/or reduce condensate formation based on the amount of water exiting the CAC. ## Claims ### Claim 1 An engine method, comprising: determining an estimated amount of water in charge air exiting a charge air cooler based on an output of an oxygen sensor positioned downstream of the charge air cooler; and adjusting engine actuators based on the estimated amount of water. ### Claim 2 (depends on 1) The method of claim 1, wherein the oxygen sensor is positioned at an outlet of the charge air cooler and wherein the oxygen sensor and charge air cooler are positioned in an intake passage upstream of engine cylinders. ### Claim 3 (depends on 1) The method of claim 1, further comprising operating the oxygen sensor in a variable voltage mode responsive to an exhaust gas recirculation flow being at or greater than a threshold. ### Claim 4 (depends on 3) The method of claim 3, wherein the threshold is based on a maximum exhaust gas recirculation flow rate for which water is a major diluent in the charge air. ### Claim 5 (depends on 3) The method of claim 3, wherein operating the oxygen sensor in the variable voltage mode includes increasing a reference voltage of the oxygen sensor from a base, first voltage to a second voltage, the second voltage higher than the first voltage. ### Claim 6 (depends on 5) The method of claim 5, wherein the estimated amount of water is estimated based on a difference in pumping current when increasing the reference voltage from the first voltage to the second voltage and wherein the estimated amount of water is further based on a saturation water value at an outlet temperature condition of the charge air cooler. ### Claim 7 (depends on 1) The method of claim 1, further comprising operating the oxygen sensor in one or more of a base mode and a variable voltage mode responsive to an exhaust gas recirculation flow being less than a threshold. ### Claim 8 (depends on 1) The method of claim 1, wherein adjusting engine actuators based on the estimated amount of water includes one or more of adjusting spark timing and/or limiting an increase in engine airflow in response to the estimated amount of water in the charge air exiting the charge air cooler being greater than a threshold. ### Claim 9 (depends on 1) The method of claim 1, wherein the estimated amount of water in the charge air exiting the charge air cooler is further based on a second output of a second oxygen sensor positioned upstream of the charge air cooler. ### Claim 10 (depends on 9) The method of claim 9, further comprising adjusting engine actuators based on charge air cooler water storage parameters, the water storage parameters including one or more of a water release amount from the charge air cooler, a water release rate from the charge air cooler, a water storage amount in the charge air cooler, and a water storage rate in the charge air cooler, the water storage parameters based on the output of the oxygen sensor positioned downstream of the charge air cooler and the second output of the second oxygen sensor positioned upstream of the charge air cooler. ### Claim 11 An engine method, comprising: operating a first oxygen sensor positioned at an outlet of a charge air cooler in one or more of a base mode and a variable voltage mode responsive to an exhaust gas recirculation flow relative to a threshold; and adjusting engine actuators based on water storage parameters at the charge air cooler, the water storage parameters estimated based on an output of the first oxygen sensor. ### Claim 12 (depends on 11) The method of claim 11, wherein the water storage parameters include an amount of water in charge air exiting the charge air cooler and wherein adjusting engine actuators includes one or more of adjusting spark timing and limiting engine airflow responsive to the amount of water in the charge air exiting the charge air cooler increasing above a threshold amount. ### Claim 13 (depends on 12) The method of claim 12, wherein the amount of water is estimated based on a pumping current of the first oxygen sensor and a saturation water value at an outlet temperature condition of the charge air cooler. ### Claim 14 (depends on 12) The method of claim 12, wherein adjusting spark timing includes advancing spark timing when a pedal position is increasing and retarding spark timing when the pedal position is below a threshold position. ### Claim 15 (depends on 11) The method of claim 11, wherein the water storage parameters further include a water release rate from the charge air cooler, a water storage rate at the charge air cooler, and a water storage amount at the charge air cooler, wherein the exhaust gas recirculation flow is an estimated flow of exhaust gas flowing from an exhaust passage to an intake passage via an exhaust gas recirculation passage, where the exhaust gas recirculation passage is coupled to the intake passage upstream of the charge air cooler, and wherein the charge air cooler and first oxygen sensor are positioned in the intake passage upstream of engine cylinders. ### Claim 16 (depends on 15) The method of claim 15, wherein the water release rate, the water storage rate, and the water storage amount are based on the output of the first oxygen sensor and an output of a second oxygen sensor positioned at an inlet of the charge air cooler. ### Claim 17 (depends on 16) The method of claim 16, wherein adjusting engine actuators includes one or more of adjusting spark timing and mass air flow in response to the water release rate increasing above a threshold rate. ### Claim 18 (depends on 16) The method of claim 16, wherein adjusting engine actuators includes one or more of adjusting vehicle grille shutters, engine cooling fans, and a charge air cooler coolant pump to decrease a cooling efficiency of the charge air cooler in response to the water storage rate increasing above a threshold rate and wherein adjusting engine actuators includes increasing engine airflow to purge condensate from the charge air cooler in response to the water storage amount increasing above a threshold amount. ### Claim 19 An engine system, comprising: an intake manifold; a charge air cooler positioned upstream of the intake manifold; a first oxygen sensor positioned at an outlet of the charge air cooler; and a controller with computer readable instructions for adjusting engine actuators based on an amount of water in charge air exiting the charge air cooler, the amount of water estimated based on an output of the first oxygen sensor. ### Claim 20 (depends on 19) The system of claim 19, further comprising a second oxygen sensor positioned at an inlet of the charge air cooler and wherein engine actuators are further adjusted based on water storage at the charge air cooler, the water storage estimated based on the output of the first oxygen sensor and an output of the second oxygen sensor.