Model-based method of estimating crankcase oil pressure in an internal combustion engine
First Claim
1. A method of estimating a pressure of oil in an internal combustion engine, comprising the steps of:
- determining a speed of the engine and a temperature of the oil; and
utilizing the determined engine speed and oil temperature to estimate the oil pressure as a sum of static and dynamic components, where the dynamic component includes a first portion that primarily accounts for flow-related effects on the oil pressure, and a second portion that primarily accounts for temperature-related effects on the oil pressure.
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Abstract
An improved method of estimating the oil pressure of an internal combustion engine utilizes a physical model that takes into account both engine speed and engine oil temperature. The oil pressure is estimated as the sum of static and dynamic components, where the dynamic component includes a first portion that primarily models flow-related effects, and a second portion that primarily models temperature-related effects. The constants and temperature-related variables of the physical model are combined to form one constant calibration value, and two temperature-dependent calibration values. The parameters of the physical model provide a starting point for the calibration values, and the calibration values are then tuned during a calibration procedure so that the estimated oil pressure tracks an accurate measure of the oil pressure during both steady-state and transient engine operating conditions.
8 Citations
5 Claims
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1. A method of estimating a pressure of oil in an internal combustion engine, comprising the steps of:
-
determining a speed of the engine and a temperature of the oil; and
utilizing the determined engine speed and oil temperature to estimate the oil pressure as a sum of static and dynamic components, where the dynamic component includes a first portion that primarily accounts for flow-related effects on the oil pressure, and a second portion that primarily accounts for temperature-related effects on the oil pressure. - View Dependent Claims (2, 3, 4, 5)
determining the first portion of the dynamic component according to a product (C2*ES½
), where C2 is a calibration term that varies as a function of the determined temperature of the oil, and ES is the determined speed of the engine.
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5. The method of claim 1, including the step of:
determining the second portion of the dynamic component according to a product (C3*OT*ES½
), where C3 is a calibration term that varies as a function of the determined temperature of the oil, OT is the determined temperature of the oil, and ES is the determined speed of the engine.
Specification