Ambient air temperature prediction
First Claim
1. A method for generating a Predicted Ambient Temperature (PAT) of air around a vehicle for controlling vehicle operation, based on vehicle Intake Air Temperature (IAT), vehicle speed (VSS), vehicle intake airflow (MAF), engine run time (ERT) and Last Predicted Ambient Temperature (LPAT), comprising the steps of:
- increasing a count value and generating the PAT based on IAT or LPAT when MAF and VSS are below respective thresholds and said count value has not yet reached a predetermined count value;
decreasing the count value and generating the PAT based on IAT or LPAT when at least one of MAF and VSS exceeds or is equal to its respective threshold and said count value has not yet reached the predetermined count value;
when said count value reaches the predetermined count value, determining whether ERT exceeds a corresponding threshold value; and
in response to said determining step, generating the PAT based on IAT or LPAT if said ERT does not exceed the corresponding threshold value, otherwise generating the PAT based on an offset temperature that is obtained by subtracting an offset value from IAT.
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Accused Products
Abstract
Methods and apparatus are provided for predicting ambient air temperature (PAT) around a vehicle (and partly controlling vehicle operation) based on Mass Air Flow (MAF), Vehicle Speed (VSS), Inlet Air Temperature (IAT), Engine Run Time (ERT) and the last PAT value (LPAT). If MAF,VSS are below thresholds C1, C2 and ERT is below threshold C4, then PAT is set equal to the smaller of IAT or LPAT. If MAF,VSS,ERT exceed C1, C2, C4, as for example, in steady run operation, then after an interval PAT approaches IAT−C5+/−C6 where C5 and C6 are stored parameters. An idle counter increments when MAF<C1, VSS<C2 is TRUE and decrements by parameter C3 when FALSE and must reach zero before the PAT steady run value is set. This improves prediction accuracy during transition from idle to steady state running. The PAT estimation process is repeated about every 10 seconds.
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Citations
18 Claims
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1. A method for generating a Predicted Ambient Temperature (PAT) of air around a vehicle for controlling vehicle operation, based on vehicle Intake Air Temperature (IAT), vehicle speed (VSS), vehicle intake airflow (MAF), engine run time (ERT) and Last Predicted Ambient Temperature (LPAT), comprising the steps of:
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increasing a count value and generating the PAT based on IAT or LPAT when MAF and VSS are below respective thresholds and said count value has not yet reached a predetermined count value; decreasing the count value and generating the PAT based on IAT or LPAT when at least one of MAF and VSS exceeds or is equal to its respective threshold and said count value has not yet reached the predetermined count value; when said count value reaches the predetermined count value, determining whether ERT exceeds a corresponding threshold value; and in response to said determining step, generating the PAT based on IAT or LPAT if said ERT does not exceed the corresponding threshold value, otherwise generating the PAT based on an offset temperature that is obtained by subtracting an offset value from IAT. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system for temperature prediction comprising:
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a) a program for obtaining a Predicting Ambient Temperature (PAT) of air surrounding a vehicle by; increasing a count value and generating the PAT based on IAT or LPAT when MAF and VSS are below respective thresholds and said count value has not yet reached a predetermined count value; decreasing the count value and generating the PAT based on IAT or LPAT when at least one of MAF and VSS exceeds or is equal to its respective threshold and said count value has not yet reached the predetermined count value; when said count value reaches the predetermined count value, determining whether ERT exceeds a corresponding threshold value; and in response to said determining, generating the PAT based on IAT or LPAT if said ERT does not exceed the corresponding threshold value, otherwise generating the PAT based on an offset temperature that is obtained by subtracting an offset value from IAT; and b) signal bearing media bearing said program. - View Dependent Claims (11, 12)
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13. A system for controlling in part operation of a vehicle using Predicted Ambient Temperature (PAT) value, comprising:
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a controller comprising a processor and a memory coupled to the processor; at least one interface unit coupled to the controller and configured to provide vehicle operating variables MAF, VSS, IAT, ERT and LPAT to the controller; and a prediction program residing in the memory and being executed by the processor for providing the PAT of air surrounding the vehicle, wherein the prediction program comprises computer-executable instructions configured; to increase a count value and to generate the PAT based on IAT or LPAT when MAF and VSS are below respective thresholds and said count value has not yet reached a predetermined count value; to decrease the count value and to generate the PAT based on IAT or LPAT when at least one of MAF and VSS exceeds or is equal to its respective threshold and said count value has not yet reached the predetermined count value; when said count value reaches the predetermined count value, to determine whether ERT exceeds a corresponding threshold value; and to generate, in response to said determination, the PAT based on IAT or LPAT if said ERT does not exceed the corresponding threshold value, otherwise to generate the PAT based on an offset temperature that is obtained by subtracting an offset value from IAT. - View Dependent Claims (14, 15, 16, 17, 18)
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Specification