Cylinder air charge estimation system and method for internal combustion engine including exhaust gas recirculation
First Claim
1. A method for determining a mass of charged air in a cylinder of an internal combustion engine, said engine having an intake manifold communicating with an engine cylinder, said method comprising the steps of:
- determining a temperature of a combination of charged air and recirculated exhaust gas inducted into said cylinder of said engine;
determining a total mass flow rate responsive to a pressure in said intake manifold and said temperature, said total mass flow rate including a mass flow rate of said charged air and a mass flow rate of said recirculated exhaust gas; and
, calculating said mass of charged air from said total mass flow rate.
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Accused Products
Abstract
A system (12) and method for determining the charged air mass in a cylinder (14) of an internal combustion engine (10) are provided. The system (12) includes an electronic control unit (ECU) (58) configured to determine a temperature of the combination of charged air and recirculated exhaust gas inducted into the cylinder (14). The ECU (58) is further configured to determine a total mass flow rate of the combination of inducted air and recirculated exhaust gas based on a pressure in an intake manifold (22) of the engine (10) and the previously determined temperature. Finally, the ECU (58) is configured to determine the mass of charged air in the cylinder (14) from the total mass flow rate.
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Citations
30 Claims
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1. A method for determining a mass of charged air in a cylinder of an internal combustion engine, said engine having an intake manifold communicating with an engine cylinder, said method comprising the steps of:
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determining a temperature of a combination of charged air and recirculated exhaust gas inducted into said cylinder of said engine;
determining a total mass flow rate responsive to a pressure in said intake manifold and said temperature, said total mass flow rate including a mass flow rate of said charged air and a mass flow rate of said recirculated exhaust gas; and
,calculating said mass of charged air from said total mass flow rate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
determining a temperature of said charged air;
determining a temperature of said recirculated exhaust gas;
determining said mass flow rate of said recirculated exhaust gas; and
,calculating said temperature of said combination responsive to said charged air temperature, said recirculated exhaust gas temperature, said recirculated exhaust gas mass flow rate and a previously estimated charged air mass flow rate.
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3. The method of claim 2 wherein said substep of determining said mass flow rate of recirculated exhaust gas includes the substeps of:
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measuring a first pressure on a first side of an orifice disposed in a flow path of said recirculated exhaust gas;
measuring a second pressure on a second side of said orifice; and
,calculating said mass flow rate of recirculated exhaust gas responsive to said first and second pressures.
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4. The method of claim 3 wherein said second pressure comprises an absolute pressure in said intake manifold.
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5. The method of claim 1 wherein said step of determining a total mass flow rate includes the substeps of:
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determining a volumetric efficiency of said engine; and
,solving the ideal gas law for said total mass flow rate using said volumetric efficiency, said pressure in said intake manifold, a speed of said engine, and said temperature of said combination of charged air and recirculated exhaust gas.
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6. The method of claim 5 wherein said substep of determining a volumetric efficiency includes the substeps of:
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determining a speed of said engine and an absolute pressure in said intake manifold; and
,obtaining said volumetric efficiency responsive to said speed and said absolute pressure.
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7. The method of claim 6 wherein said step of obtaining said volumetric efficiency includes the substep of accessing a memory responsive to said speed and said absolute pressure.
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8. The method of claim 7 wherein said step of obtaining said volumetric efficiency further includes the substep of interpolating between a plurality of values retrieved from said memory responsive to said speed and said absolute pressure.
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9. The method of claim 1 wherein said step of calculating said mass of charged air from said total mass flow rate includes the substeps of:
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subtracting said mass flow rate of recirculated exhaust gas from said total mass flow rate to obtain said mass flow rate of said charged air; and
,calculating said mass of charged air responsive to said mass flow rate of said charged air.
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10. A system for determining a mass of charged air in a cylinder of an internal combustion engine, said engine having an intake manifold communicating with an engine cylinder, said system comprising:
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an electronic control unit configured to determine a temperature of a combination of charged air and recirculated exhaust gas inducted into said cylinder of said engine, to determine a total mass flow rate responsive to a pressure in said intake manifold and said temperature, said total mass flow rate including a mass flow rate of said charged air and a mass flow rate of said recirculated exhaust gas, and to calculate said mass of charged air from said total mass flow rate. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
a first pressure sensor disposed on a first side of an orifice disposed in a flow path of said recirculated engine gas; and
,a second pressure sensor disposed on a second side of said orifice wherein said electronic control unit is further configured, in determining said mass flow rate of recirculated engine gas, to calculate said mass flow rate of recirculated engine gas responsive to said first and second pressures.
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13. The system of claim 12 wherein said second pressure comprises an absolute pressure in said intake manifold.
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14. The system of claim 10 wherein said electronic control unit is further configured, in determining said total mass flow rate, to determine a volumetric efficiency of said engine, and to solve the ideal gas law for said total mass flow rate using said volumetric efficiency, said pressure in said intake manifold, a speed of said engine, and said temperature of said combination of charged air and recirculated exhaust gas.
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15. The system of claim 14 wherein said system includes:
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means for determining a speed of said engine; and
,a sensor for measuring an absolute pressure in said intake manifold wherein said electronic control unit is further configured, in determining said volumetric efficiency of said engine, to obtain said volumetric efficiency responsive to said speed and said absolute pressure.
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16. The system of claim 15, further comprising a memory and wherein said electronic control unit is further configured, in obtaining said volumetric efficiency of said engine, to access said memory responsive to said speed and said absolute pressure.
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17. The system of claim 16 wherein said electronic control unit is further configured, in obtaining said volumetric efficiency of said engine, to interpolate between a plurality of values retrieved from said memory responsive to said speed and said absolute pressure.
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18. The system of claim 10 wherein said electronic control unit is further configured, in determining said mass of charged air from said total mass flow rate, to subtract said mass flow rate of recirculated engine gas from said total mass flow rate to obtain said mass flow rate of said charged air and to calculate said mass of charged air responsive to said mass flow rate of said charged air.
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19. An article of manufacture, comprising:
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a computer storage medium having a computer program encoded therein for determining a mass of charged air in a cylinder of an internal combustion engine, said engine having an intake manifold communicating with an engine cylinder, said computer program including;
code for determining a temperature of a combination of charged air and recirculated exhaust gas inducted into said cylinder of said engine;
code for determining a total mass flow rate responsive to a pressure in said intake manifold and said temperature, said total mass flow rate including a mass flow rate of said charged air and a mass flow rate of said recirculated exhaust gas; and
,code for calculating said mass of charged air from said total mass flow rate. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27)
code for determining said mass flow rate of said recirculated exhaust gas; and
,code for calculating said temperature of said combination responsive to a temperature of said charged air, a temperature of said recirculated exhaust gas, said recirculated exhaust gas mass flow rate and a previously estimated charged air mass flow rate.
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21. The article of manufacture of claim 20 wherein said code for determining said mass flow rate of recirculated exhaust gas includes code for calculating said mass flow rate of recirculated exhaust gas responsive to a first pressure on a first side of an orifice disposed in a flow path of said recirculated exhaust gas and a second pressure on a second side of said orifice.
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22. The article of manufacture of claim 21 wherein said second pressure comprises an absolute pressure in said intake manifold.
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23. The article of manufacture of claim 19 wherein said code for determining a total mass flow rate includes:
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code for determining a volumetric efficiency of said engine; and
,code for solving the ideal gas law for said total mass flow rate using said volumetric efficiency, said pressure in said intake manifold, a speed of said engine, and said temperature of said combination of charged air and recirculated exhaust gas.
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24. The article of manufacture of claim 23 wherein said code for determining a volumetric efficiency includes code for obtaining said volumetric efficiency responsive to a speed of said engine and an absolute pressure in said intake manifold.
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25. The article of manufacture of claim 24 wherein said code for obtaining said volumetric efficiency includes code for accessing a memory responsive to said speed and said absolute pressure.
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26. The article of manufacture of claim 25 wherein said code for obtaining said volumetric efficiency further includes code for interpolating between a plurality of values retrieved from said memory responsive to said speed and said absolute pressure.
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27. The article of manufacture of claim 19 wherein said code for calculating said mass of charged air from said total mass flow rate further includes:
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code for subtracting said mass flow rate of recirculated exhaust gas from said total mass flow rate to obtain said mass flow rate of said charged air; and
,code for calculating said mass of charged air responsive to said mass flow rate of said charged air.
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28. A method for estimating a temperature in a cylinder of an internal combustion engine, comprising the steps of:
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determining a mass flow rate for charged air inducted into said cylinder;
determining a mass flow rate for recirculated exhaust gas inducted into said cylinder;
determining a temperature of said charged air;
determining a temperature of said recirculated exhaust gas; and
,calculating said temperature in said cylinder responsive to said mass flow rates of said charged air and said recirculated exhaust gas and said temperatures of said charged air and said recirculated exhaust gas.
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29. A system for estimating a temperature in a cylinder of an internal combustion engine, comprising:
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an electronic control unit configured to;
determine a mass flow rate for charged air inducted into said cylinder;
determine a mass flow rate for recirculated exhaust gas inducted into said cylinder;
determine a temperature of said charged air;
determine a temperature of said recirculated exhaust gas; and
,calculate said temperature in said cylinder responsive to said mass flow rates of said charged air and said recirculated exhaust gas and said temperatures of said charged air and said recirculated exhaust gas.
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30. An article of manufacture comprising:
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a computer storage medium having a computer program encoded therein for estimating a temperature in a cylinder of an internal combustion engine, said computer program including;
code for determining a mass flow rate for charged air inducted into said cylinder;
code for determining a mass flow rate for recirculated exhaust gas inducted into said cylinder;
code for determining a temperature of said charged air;
code for determining a temperature of said recirculated exhaust gas; and
,code for calculating said temperature in said cylinder responsive to said mass flow rates of said charged air and said recirculated exhaust gas and said temperatures of said charged air and said recirculated exhaust gas.
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Specification