Method and device for controlling the exhaust gas recirculation in an internal-combustion engine based on the measurement of the oxygen concentration in the gaseous mixture taken in by the engine
First Claim
1. A device for controlling the exhaust gas recirculation in an internal-combustion engine, said engine being provided with an air-intake system, a gas-exhaust system, and an exhaust-gas-recirculation system;
- said device comprising measuring means for measuring the oxygen concentration in the air/recirculated-exhaust-gas mixture taken in by the engine; and
control means connected to said measuring means and to the exhaust-gas-recirculation system for controlling the exhaust gas recirculation on the basis of The oxygen concentration in the mixture taken in by the engine said control means comprisingmeans for calculating the concentration of recirculated exhaust gases (% EGR) in the mixture taken in by the engine as a function of the oxygen concentration in the mixture itself, in particular according to the following equation;
wherein % O2,air is the oxygen concentration in the air and % O2,air+EGR is the oxygen concentration in the mixture taken in;
and wherein said control means implements a closed-loop control of the exhaust gas recirculation based on the concentration of recirculated exhaust gases (% EGR) in the mixture taken in by the engine.
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Abstract
A method and a device for controlling the exhaust gas recirculation in an internal-combustion engine are described herein. The engine is provided with an air-intake system, a gas-exhaust system, and an exhaust-gas-recirculation system. A linear oxygen sensor is arranged along the air-intake system in a section traversed, in use, by the air/recirculated-exhaust-gas mixture, for measuring the oxygen concentration in the mixture itself An electronic control unit is connected to the oxygen sensor and to the exhaust-gas-recirculation system for controlling the flow rate of recirculated exhaust gases on the basis of the oxygen concentration in the mixture taken in by the engine. In particular, the oxygen sensor is a UHEGO probe.
62 Citations
38 Claims
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1. A device for controlling the exhaust gas recirculation in an internal-combustion engine, said engine being provided with an air-intake system, a gas-exhaust system, and an exhaust-gas-recirculation system;
- said device comprising measuring means for measuring the oxygen concentration in the air/recirculated-exhaust-gas mixture taken in by the engine; and
control means connected to said measuring means and to the exhaust-gas-recirculation system for controlling the exhaust gas recirculation on the basis of The oxygen concentration in the mixture taken in by the engine said control means comprisingmeans for calculating the concentration of recirculated exhaust gases (% EGR) in the mixture taken in by the engine as a function of the oxygen concentration in the mixture itself, in particular according to the following equation; wherein % O2,air is the oxygen concentration in the air and % O2,air+EGR is the oxygen concentration in the mixture taken in; and wherein said control means implements a closed-loop control of the exhaust gas recirculation based on the concentration of recirculated exhaust gases (% EGR) in the mixture taken in by the engine. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
in which η
vol is the volumetric efficiency, R is a constant characteristic of the gaseous mixture, rpm is the engine r.p.m. and Vcap is the engine capacity; andmeans for calculating the flow rate ({dot over (M)}fresh — air) of air taken in by the engine as a function of the flow rate ({dot over (M)}intake) of the mixture taken in by the engine and the concentration of recirculated exhaust gases (% EGR) in the mixture itself, in particular according to the following equation;
{dot over (M)}fresh— air=(1−
% EGR)·
{dot over (M)}intake
- said device comprising measuring means for measuring the oxygen concentration in the air/recirculated-exhaust-gas mixture taken in by the engine; and
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7. The device according to claim 1, further comprising means for measuring the oxygen concentration in the exhaust gases;
and wherein said control means further comprise; means for calculating the temperature (Tmanifold) of the mixture taken in by the engine as a function of the oxygen concentration in the exhaust gases and the concentration of recirculated exhaust gases (% EGR) in the mixture itself.
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8. The device according to claim 7, wherein said means for calculating the temperature (Tmanifold) of the mixture taken in by the engine comprise:
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means for calculating the flow rate ({dot over (M)}intake) of the mixture taken in by the engine as a function of the oxygen concentration in the exhaust gases and the concentration of recirculated exhaust gases (% EGR) in the mixture itself; and means for calculating the temperature (Tmanifold) of the mixture taken in by the engine as a function of the flow rate ({dot over (M)}intake) of the mixture taken in by the engine.
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9. The device according to claim 7, wherein said means for measuring the oxygen concentration in the exhaust gases comprise an oxygen sensor arranged in the gas-exhaust system.
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10. The device according to claim 9, wherein said oxygen sensor is a linear oxygen sensor.
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11. The device according to claim 9, wherein said oxygen sensor is a UHEGO probe.
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12. A method for controlling the exhaust gas recirculation in an internal-combustion engine, said engine being provided with an air-intake system, a gas-exhaust system, and an exhaust-gas-recirculation system;
- said method being characterized by comprising the steps of;
measuring the oxygen concentration in the air/recirculated-exhaust-gas mixture taken in by the engine; and controlling the exhaust gas recirculation on the basis of the oxygen concentration in the mixture taken in by the engine which comprises the steps of; calculating the concentration of recirculated exhaust gases (% EGR) in the mixture taken in by the engine as a function of the oxygen concentration in the mixture itself, in particular according to the following equation; in which % O2,air is the oxygen concentration in the air and % O2,air+EGR is the oxygen concentration in the mixture; and controlling via a closed-loop control the exhaust gas recirculation on the basis of the concentration of recirculated exhaust gases (% EGR) in the mixture taken in by the engine. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
in which η
vol is the volumetric efficiency, R is a constant characteristic of the gaseous mixture, rpm is the engine r.p.m. and Vcap is the engine capacity; andcalculating the flow rate ({dot over (M)}fresh — air) of air taken in by the engine as a function of the flow rate ({dot over (M)}intake) of the mixture taken in by the engine and the concentration of recirculated exhaust gases (% EGR) in the mixture itself, in particular according to the following equation;
{dot over (M)}fresh— air=(1−
% EGR)·
{dot over (M)}intake
- said method being characterized by comprising the steps of;
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18. The method according to claim 17, further comprising the step of:
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measuring the oxygen concentration in the exhaust gases, and wherein said step of controlling the exhaust gas recirculation on the basis of the oxygen concentration in the mixture taken in by the engine further comprises the step of; calculating the temperature (Tmanifold) of the mixture taken in by the engine as a function of the oxygen concentration in the exhaust gases and the concentration of recirculated exhaust gases (% EGR) in the mixture itself.
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19. The method according to claim 18, wherein said step of calculating the temperature (Tmanifold) of the mixture taken in by the engine further comprises the steps of:
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calculating the flow rate ({dot over (M)}intake) of the mixture taken in by the engine as a function of the oxygen concentration in the exhaust gases and the concentration of recirculated exhaust gases (% EGR) in the mixture itself; and calculating the temperature (Tmanifold) of the mixture taken in by the engine as a function of the flow rate ({dot over (M)}intake) of the mixture taken in by the engine.
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20. A device for determining the flow rate of air taken into an internal-combustion engine, said engine being provided with an air-intake system, a gas-exhaust system, and an exhaust-gas-recirculation system, which comprises:
- measuring means for measuring the oxygen concentration in the air/recirculated-exhaust-gas mixture taken in by the engine; and
determining means for determining the flow rate ({dot over (M)}fresh— ) of air taken in by the engine connected to said measuring means for calculating the flow rate ({dot over (M)}fresh
air— air) of air taken in by the engine as a function of the oxygen concentration in the mixture taken in by the engine. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29)
- measuring means for measuring the oxygen concentration in the air/recirculated-exhaust-gas mixture taken in by the engine; and
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30. A method for determining the flow rate of air taken into an internal-combustion engine, said engine being provided with an air-intake system, a gas-exhaust system, and an exhaust-gas-recirculation system;
- which comprises the steps of;
measuring the oxygen concentration in the air/recirculated-exhaust-gas mixture taken in by the engine; and determining the flow rate ({dot over (M)}fresh — air) of air taken in by the engine as a function of the oxygen concentration in the mixture taken in by the engine. - View Dependent Claims (31, 32, 33, 34, 35, 36)
- which comprises the steps of;
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37. A device for controlling the exhaust gas recirculation in an internal-combustion engine, said engine being provided with an air-intake system, a gas-exhaust system, and an exhaust-gas-recirculation system;
- said device comprising measuring means for measuring the oxygen concentration in the air/recirculated-exhaust-gas mixture taken in by the engine; and
control means connected to said measuring means and to the exhaust-gas-recirculation system for controlling the exhaust gas recirculation on the basis of the oxygen concentration in the mixture taken in by the engine, said control means comprising;means for calculating the concentration of recirculated exhaust gases (% EGR) in the mixture taken in by the engine as a function of the oxygen concentration in the mixture itself wherein said control means implements a closed-loop control of the exhaust gas recirculation based on the concentration of recirculated exhaust gases (% EGR) in the mixture taken in by the engine, wherein said control means further comprises; means for calculating the flow rate ({dot over (M)}intake) of the mixture taken in by the engine as a function of the pressure (Pmanifold) and the temperature (Tmanifold) of the mixture itself; and means for calculating the flow rate ({dot over (M)}fresh — air) of air taken in by the engine as a function of the flow rate ({dot over (M)}intake) of the mixture taken in by the engine and the concentration of recirculated exhaust gases (% EGR) in the mixture itself.
- said device comprising measuring means for measuring the oxygen concentration in the air/recirculated-exhaust-gas mixture taken in by the engine; and
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38. A method for controlling the exhaust gas recirculation in an internal-combustion engine, said engine being provided with an air-intake system, a gas-exhaust system, and an exhaust-gas-recirculation system;
- said method comprising the steps of;
measuring the oxygen concentration in the ak/recirculated-exhaust-gas mixture taken in by the engine; and controlling the exhaust gas recirculation on the basis of the oxygen concentration in the mixture taken in by the engine which comprises the steps of; calculating the concentration of recirculated exhaust gases (% EGR) in the mixture taken in by the engine as a function of the oxygen concentration in the mixture itself and controlling via a closed-loop control the exhaust gas recirculation on the basis of the concentration of recirculated exhaust gases (% EGR) in the mixture taken by the engine wherein said step of controlling the exhaust gas recirculation on the basis of the oxygen concentration in the mixture taken in by the engine comprises the steps of; calculating the flow rate ({dot over (M)}intake) of the mixture taken in by the engine as a function of the pressure (Pmanifold) and the temperature (Tmanifold) of the mixture itself and calculating the flow rate ({dot over (M)}fresh — air) of air taken in by the engine as a function of the flow rate ({dot over (M)}intake) of the mixture taken in by the engine and the concentration of recirculated exhaust gases (% EGR) in the mixture itself.
- said method comprising the steps of;
Specification