Method and system for identifying phase in an internal combustion engine

1. A method for identifying a phase in an internal combustion engine, the internal combustion engine comprising an even number of cylinders and fitted with at least one sensor, the method comprising:

measuring a state of the internal combustion engine using the at least one sensor;

calculating a deviation in the state from an expected set of values, wherein the expected set of values comprises a plurality of expected in-phase state values and a plurality of expected out-phase state values; and

determining the phase of the internal combustion engine based on the deviation.

2. The method according to claim 1 further comprising:

checking stability of the internal combustion engine based on at least one stability criterion.

3. The method according to claim 1 further comprising:

checking for outlier values of the state, the outlier values being values lying outside a pre-specified range.

4. The method according to claim 1 , wherein determining the phase comprises:

comparing an average in-phase deviation value with an average out-phase deviation value.

5. A method for identifying a phase in an internal combustion engine, the internal combustion engine comprising an even number of cylinders and fitted with at least one sensor, the method comprising:

measuring a state of the internal combustion engine using the at least one sensor;

calculating a deviation in the state from an expected set of values, wherein calculating the deviation comprises:

calculating at least one in-phase deviation value,

calculating at least one out-phase deviation value,

checking whether a number of the at least one in-phase deviation value and the at least one out-phase deviation value is more than a predetermined number,

calculating an average in-phase deviation value, and

calculating an average out-phase deviation value; and

determining the phase of the internal combustion engine based on the deviation.

6. The method according to claim 5 , wherein calculating the deviation further comprises:

storing the at least one in-phase deviation value and the at least one out-phase deviation value; and

storing the average in-phase deviation value and the average out-phase deviation value.

7. The method according to claim 5 , wherein calculating the deviation further comprises:

calculating a phase weight for the at least one in-phase deviation value and the at least one out-phase deviation value.

8. An automotive control system, the automotive control system controlling an internal combustion engine, the internal combustion engine comprising an even number of cylinders, the automotive control system comprising:

means for measuring a state of the internal combustion engine;

means for calculating a deviation in the state from an expected set of values, wherein the means for calculating the deviation comprises means for calculating at least one in-phase deviation value, at least one out-phase deviation value, an average in-phase deviation value, and an average out-phase deviation value; and

means for determining a phase of the internal combustion engine based on the deviation.

9. The system according to claim 8 , wherein the means for calculating the deviation further comprises:

means for checking whether a number of the at least one in-phase deviation value and the at least one out-phase deviation value is more than a predetermined number of values.

10. The system according to claim 8 , wherein the means for calculating the deviation further comprises:

means for storing the at least one in-phase deviation value and the at least one out-phase deviation value; and

means for storing the average in-phase deviation value and the average out-phase deviation value.

11. The system according to claim 8 , wherein the means for calculating the deviation further comprises:

means for calculating a phase weight for the at least one in-phase deviation value and the at least one out-phase deviation value.

12. An automotive control system, the automotive control system controlling an internal combustion engine, the internal combustion engine comprising an even number of cylinders, the automotive control system comprising:

means for measuring a state of the internal combustion engine;

means for calculating a deviation in the state from an expected set of values, wherein the expected set of values comprises a plurality of expected in-phase state values and a plurality of expected out-phase state values; and

means for determining a phase of the internal combustion engine based on the deviation.

13. The system according to claim 12 further comprising:

means for checking stability of the internal combustion engine based on at least one stability criterion.

14. The system according to claim 12 further comprising:

means for checking outlier values of the state, the outlier values being values lying outside a pre-specified range.

15. The system according to claim 12 , wherein the plurality of expected in-phase state values comprise at least one expected lean in-phase state value and at least one expected rich in-phase state value.

16. The system according to claim 12 , wherein the plurality of expected out-phase state values comprise at least one expected lean out-phase state value and at least one expected rich out-phase state value.

17. The system according to claim 12 , wherein the means for determining the phase comprises:

means for comparing an average in-phase deviation value and an average out-phase deviation value.

18. The system according to claim 12 , wherein the means for measuring the state comprises at least one of sensor.

19. The system according to claim 18 , wherein the at least one sensor comprises an oxygen sensor.