EXHAUST GAS RECIRCULATION CONTROL SYSTEMS AND METHODS FOR LOW ENGINE DELTA PRESSURE CONDITIONS

• US 20130268176A1
• Filed: 04/05/2012
• Published: 10/10/2013
• Est. Priority Date: 04/05/2012
• Status: Abandoned Application

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Song, B. Jerry, York, Gregory J., Wasberg, Jon C., Hall, Eric M.
• Application Number:
  US13/440,570
• Publication Number:
  US 20130268176A1
• Time in Patent Office: Days
• US Class Current: 701/102
• CPC Class Codes: F02D 21/08 the other gas being the exhaust gas of engine
• CPC Class Codes: F02D 2200/0402 the parameter being determined by using a model of the engine intake or its components
• CPC Class Codes: F02D 2200/0406 Intake manifold pressure
• CPC Class Codes: F02D 41/0072 Estimating, calculating or determining the EGR rate, amount or flow sensors in EGR systems F02M26/45
• CPC Class Codes: F02D 41/144 Sensor in intake manifold
• CPC Class Codes: F02D 41/1441 Plural sensors
• CPC Class Codes: F02D 41/1454 the characteristics being an oxygen content or concentration or the air-fuel ratio
• CPC Class Codes: F02M 26/25 with coolers having bypasses
• CPC Class Codes: F02M 26/46 for determining the characteristics of gases, e.g. composition
• CPC Class Codes: F02M 35/10393 for characterising a multi-component mixture, e.g. for the composition such as humidity, density or viscosity
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A partial pressure determination module: determines a first partial pressure of oxygen in an intake manifold of an engine based on an output of a first oxygen sensor measuring oxygen in the intake manifold; and determines a second partial pressure of oxygen in an exhaust system based on an output of a second oxygen sensor measuring oxygen in the exhaust system. A concentration determination module: determines a concentration of oxygen in the intake manifold based on the first partial pressure and an intake manifold; and determines a concentration of oxygen in the exhaust system based on the second partial pressure. A flowrate determination module determines a mass flowrate of exhaust gas recirculation (EGR) based on the concentration of oxygen in the intake manifold and the concentration of oxygen in the exhaust system. An actuator control module controls an engine operating parameter based on the mass flowrate of EGR.

Claims

1. An engine control system for a vehicle, comprising:

a partial pressure determination module that;

determines a first partial pressure of oxygen in an intake manifold of an engine based on an output of a first oxygen sensor measuring oxygen in the intake manifold; and

determines a second partial pressure of oxygen in an exhaust system based on an output of a second oxygen sensor measuring oxygen in the exhaust system;

a concentration determination module that;

determines a concentration of oxygen in the intake manifold based on the first partial pressure and an intake manifold; and

determines a concentration of oxygen in the exhaust system based on the second partial pressure;

a flowrate determination module that determines a mass flowrate of exhaust gas recirculation (EGR) based on the concentration of oxygen in the intake manifold and the concentration of oxygen in the exhaust system; and

an actuator control module that controls an engine operating parameter based on the mass flowrate of EGR.

2. The engine control system of claim 1 wherein the concentration determination module determines the concentration of oxygen in the exhaust system further based on a pressure at the second oxygen sensor.

3. The engine control system of claim 1 wherein the concentration determination module determines the concentration of oxygen in the intake manifold using one of a function and a mapping that relates the first partial pressure and the intake manifold pressure to the concentration of oxygen in the intake manifold.

4. The engine control system of claim 1 further comprising a fraction determination module that determines an EGR fraction based on the concentration of oxygen in the intake manifold, the concentration of oxygen in the exhaust system, and a concentration of oxygen in ambient air,

wherein the flowrate determination module determines the mass flowrate of EGR based on the EGR fraction.

5. The engine control system of claim 4 wherein the fraction determination module sets the EGR fraction equal to a first value divided by a second value,

wherein the first value is equal to the concentration of oxygen in ambient air minus the concentration of oxygen in the intake manifold, and

wherein the second value is equal to the concentration of oxygen in ambient air minus the concentration of oxygen in the exhaust system.

6. The engine control system of claim 4 wherein the flowrate determination module determines the mass flowrate of EGR further based on a mass flowrate of air into the engine.

7. The engine control system of claim 6 wherein the flowrate determination module sets the mass flowrate of EGR equal to a third value divided by a fourth value,

wherein the third value is equal to a product of the EGR fraction and the mass flowrate of air into the engine, and

wherein the fourth value is equal to one minus the EGR fraction.

8. The engine control system of claim 1 further comprising a torque estimation module that estimates a torque output of the engine based on the mass flowrate of EGR,

wherein the actuator control module selectively adjusts opening of a throttle valve based on the torque output of the engine.

9. The engine control system of claim 1 wherein the actuator control module selectively adjusts a spark timing based on the mass flowrate of EGR.

10. The engine control system of claim 1 wherein the actuator control module selectively adjusts opening of an EGR valve based on the mass flowrate of EGR.

11. An engine control method for a vehicle, comprising:

determining a first partial pressure of oxygen in an intake manifold of an engine based on an output of a first oxygen sensor measuring oxygen in the intake manifold;

determining a second partial pressure of oxygen in an exhaust system based on an output of a second oxygen sensor measuring oxygen in the exhaust system;

determining a concentration of oxygen in the intake manifold based on the first partial pressure and an intake manifold;

determining a concentration of oxygen in the exhaust system based on the second partial pressure;

determining a mass flowrate of exhaust gas recirculation (EGR) based on the concentration of oxygen in the intake manifold and the concentration of oxygen in the exhaust system; and

controlling an engine operating parameter based on the mass flowrate of EGR.

12. The engine control method of claim 11 further comprising determining the concentration of oxygen in the exhaust system further based on a pressure at the second oxygen sensor.

13. The engine control method of claim 11 further comprising determining the concentration of oxygen in the intake manifold using one of a function and a mapping that relates the first partial pressure and the intake manifold pressure to the concentration of oxygen in the intake manifold.

14. The engine control method of claim 11 further comprising:

determining an EGR fraction based on the concentration of oxygen in the intake manifold, the concentration of oxygen in the exhaust system, and a concentration of oxygen in ambient air; and

determining the mass flowrate of EGR based on the EGR fraction.

15. The engine control method of claim 14 further comprising setting the EGR fraction equal to a first value divided by a second value,

wherein the first value is equal to the concentration of oxygen in ambient air minus the concentration of oxygen in the intake manifold, and

wherein the second value is equal to the concentration of oxygen in ambient air minus the concentration of oxygen in the exhaust system.

16. The engine control method of claim 14 further comprising determining the mass flowrate of EGR further based on a mass flowrate of air into the engine.

17. The engine control method of claim 16 further comprising setting the mass flowrate of EGR equal to a third value divided by a fourth value,

wherein the third value is equal to a product of the EGR fraction and the mass flowrate of air into the engine, and

wherein the fourth value is equal to one minus the EGR fraction.

18. The engine control method of claim 11 further comprising:

estimating a torque output of the engine based on the mass flowrate of EGR; and

selectively adjusting opening of a throttle valve based on the torque output of the engine.

19. The engine control method of claim 11 further comprising selectively adjusting a spark timing based on the mass flowrate of EGR.

20. The engine control method of claim 11 further comprising selectively adjusting opening of an EGR valve based on the mass flowrate of EGR.