System and method of controlling air-charge in direct injection lean-burn engines
First Claim
1. A method of controlling air charge in a direct-injection, spark-ignition engine having an exhaust gas recirculation (EGR) valve connecting the exhaust manifold and intake manifold of the engine, and an electronically controlled throttle (ETC) valve controlling air flow from the atmosphere to the intake manifold of said engine, comprising a sequence of the following steps:
- generating an intake manifold pressure value which is indicative of measured intake manifold pressure;
determining a desired intake manifold pressure value;
determining a desired EGR valve position;
determining a desired ETC valve position;
adjusting said ETC valve position in accordance with said desired ETC valve position; and
adjusting EGR valve position by an amount that is proportional to the error and the time integral of the error between said actual intake pressure value and said desired intake pressure value.
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Abstract
A method and system for controlling the air charge in a direct injection spark ignition engine that provides proportional plus integral control in positioning an electronic throttle control valve and an exhaust gas recirculating valve in order to compensate for uncertainties in the EGR valve flow area. An adaptation algorithm is used to improve the estimate of in-cylinder flow and throttle open-loop control.
49 Citations
20 Claims
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1. A method of controlling air charge in a direct-injection, spark-ignition engine having an exhaust gas recirculation (EGR) valve connecting the exhaust manifold and intake manifold of the engine, and an electronically controlled throttle (ETC) valve controlling air flow from the atmosphere to the intake manifold of said engine, comprising a sequence of the following steps:
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generating an intake manifold pressure value which is indicative of measured intake manifold pressure;
determining a desired intake manifold pressure value;
determining a desired EGR valve position;
determining a desired ETC valve position;
adjusting said ETC valve position in accordance with said desired ETC valve position; and
adjusting EGR valve position by an amount that is proportional to the error and the time integral of the error between said actual intake pressure value and said desired intake pressure value. - View Dependent Claims (2, 3, 4)
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4. The method as set forth in claim 1 wherein the EGR and ETC valve positions are determined in accordance with the following equations:
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5. A method of controlling air charge in a direct-injection, spark-ignition engine having an exhaust gas recirculation (EGR) valve connecting the exhaust manifold and intake manifold of the engine, and an electronically controlled throttle (ETC) valve controlling air flow from the atmosphere to the intake manifold of said engine, comprising a sequence of the following steps:
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generating a pressure value which is indicative of actual intake manifold pressure;
generating a mass air flow value which is indicative of the actual mass air flow through said ECT valve;
generating a temperature value which is indicative of actual intake manifold temperature;
estimating the total mass flow rate into a cylinder;
estimating the mass flow rate through said EGR valve as a function of said pressure value, mass air flow through said ECT valve, and estimated total mass flow rate into said cylinder; and
adjusting said EGR valve position by an amount that is proportional to the error and the time integral of the error between said desired flow rate through said EGR valve and the estimated mass flow rate through said EGR valve. - View Dependent Claims (6, 7, 8, 9, 10, 11)
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8. The method as set forth in claim 7 wherein the step of adjusting said ETC valve position is governed by the following equation:
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9. The method as set forth in claim 8 including the additional step of adjusting the estimated total mass flow into a cylinder and the estimated total flow through the throttle to compensate for component variation and uncertainty.
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10. The method as set forth in claim 9 wherein the adjusting step is performed when the EGR valve is closed.
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11. The method as set forth in claim 10 wherein the total mass flow into the cylinder is estimated from the time rate of change of the intake manifold pressure and the estimated mass flow is adjusted using a prediction error based algorithm.
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12. A system for controlling the air charge in a direct injection spark ignition engine comprising:
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an exhaust gas recirculating (EGR) valve connecting an intake manifold and an exhaust manifold of the engine;
an electronically controlled throttle (ETC) valve controlling air flow from the atmosphere to the intake manifold of said engine;
a manifold absolute pressure (MAP) sensor for sensing the actual intake manifold pressure;
a mass air flow (MAF) sensor for sensing actual mass air flow through said ECT valve;
a temperature sensor for sensing intake manifold temperature;
a proportional plus integral controller for positioning said ETC valve as a function of a desired ETC valve position, the pressure difference between an actual and desired intake manifold pressure, and the integral of said pressure difference and for positioning said EGR valve as a function of a desired EGR valve position, the flow rate difference between an estimated EGR flow rate and a desired EGR flow rate, and the integral of said flow rate difference. - View Dependent Claims (13, 14, 15, 18, 19, 20)
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15. The system of claim 14 wherein said controller adjusts the estimate of mass flow rate into a cylinder and the estimate of the intake manifold temperature.
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18. The system of claim 15 wherein said controller adjusts the estimate of mass flow rate into a cylinder.
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19. The system of claim 18 wherein the total mass flow into the cylinder is adapted using the time rate of change of the intake manifold pressure and a prediction error based algorithm.
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20. The system of claim 18 wherein the total mass flow into the cylinder is adapted on the basis of the difference between the estimated pressure and the measured pressure.
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16. A system for controlling the air charge in a direct injection spark ignition engine comprising:
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an exhaust gas recirculating (EGR) valve connecting the intake manifold and exhaust manifold of the engine;
an electronically controlled throttle (ETC) valve controlling air flow from the atmosphere to the intake manifold of said engine;
a manifold absolute pressure (MAP) sensor for sensing the actual intake manifold pressure;
a mass air flow (MAF) sensor for sensing actual mass air flow through said ECT valve;
a temperature sensor for sensing intake manifold temperature;
a nonlinear proportional plus integral controller responsive to the outputs of said sensors for positioning said ETC valve and said EGR valve in accordance with the following equations;
- View Dependent Claims (17)
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Specification