Sensor based measurement and purge control of fuel vapors in internal combustion engines

1. A fuel control system for a vehicle, comprising:

a pressure compensation module that compensates an intake oxygen signal based on an intake pressure signal and that generates a compensated intake oxygen signal;

a blow-by estimation module that generates an estimated blow-by flow;

a purge flow estimation module that estimates the purge flow based on the compensated intake oxygen signal and the estimated blow-by flow; and

a fuel control estimation module that reduces fueling to injectors of an engine of the vehicle based on the purge flow.

2. The fuel control system of claim 1 , wherein the purge flow estimation module estimates a sum of blow-by flow and the purge flow based on the compensated intake oxygen signal.

3. The fuel control system of claim 2 , wherein the purge flow estimation module estimates the sum of the blow-by flow and the purge flow using a lookup table indexed by the compensated intake oxygen signal.

4. The fuel control system of claim 2 , wherein the purge flow estimation module includes a difference module that subtracts the estimated blow-by flow generated by the blow-by estimation module from the sum of the purge flow and the blow-by flow.

5. The fuel control system of claim 1 , wherein the blow-by estimation module estimates the blow-by flow based on intake manifold pressure.

6. The fuel control system of claim 1 , wherein the blow-by estimation module estimates the blow-by flow using a lookup table indexed by intake manifold pressure.

7. The fuel control system of claim 1 , wherein the blow-by estimation module estimates the estimated blow-by flow only when a purge valve is closed.

8. The fuel control system of claim 1 , wherein the purge flow estimation module estimates the purge flow only when a purge valve is open.

9. The fuel control system of claim 1 , wherein the blow-by estimation module and the purge flow estimation module are enabled only when an exhaust gas recirculation valve of the vehicle is closed.

10. The fuel control system of claim 1 , wherein the pressure compensation module compensates for static and dynamic pressure.

11. A method for controlling a fuel control system of a vehicle, comprising:

compensating an intake oxygen signal based on an intake pressure signal to generate a compensated intake oxygen signal;

generating an estimated blow-by flow;

estimating a purge flow based on the compensated intake oxygen signal and the estimated blow-by flow; and

reducing fueling to injectors of an engine of the vehicle based on the purge flow.

12. The method of claim 11 , further comprising estimating a sum of blow-by flow and the purge flow based on the compensated intake oxygen signal.

13. The method of claim 12 , further comprising estimating the sum of the blow-by flow and the purge flow using a lookup table indexed by the compensated intake oxygen signal.

14. The method of claim 12 , further comprising subtracting the estimated blow-by flow from the sum of the purge flow and the blow-by flow.

15. The method of claim 11 , further comprising estimating the blow-by flow based on intake manifold pressure.

16. The method of claim 11 , further comprising estimating the blow-by flow using a lookup table indexed by intake manifold pressure.

17. The method of claim 11 , further comprising estimating the estimated blow-by flow only when a purge valve is closed.

18. The method of claim 11 , further comprising estimating the purge flow only when a purge valve is open.

19. The method of claim 11 , further comprising enabling estimation of the blow-by flow and the purge flow only when an exhaust gas recirculation valve of the vehicle is closed.

20. The method of claim 11 , wherein the compensating the intake oxygen signal includes compensation for static and dynamic pressure.