Method for control of a tank ventilation
View Patent ↗There is described a method for determination of an application time for a tank ventilation on an internal combustion engine. An excessive enrichment of the air/fuel mixture can be avoided by means of a timely application of injection correction as result of the tank ventilation. According to said method, a threshold value comparison is carried out for a modified lambda control deviation, made up of the lambda control deviation and a pseudo lambda control deviation, whereby the pseudo lambda control deviation depends on the deviation of the lambda values from a given lambda set value.
1. A method to control a tank ventilation of an internal combustion engine, comprising:
providing a tank system to feed gas via a ventilation valve from a tank container to an intake tract of the internal combustion engine;
providing a pseudo lambda control deviation based upon a deviation of a lambda actual value from a lambda set value and based upon an engine characteristic map;
providing a modified lambda control deviation based upon a lambda control deviation and the pseudo lambda control deviation; and
applying an injection correction based upon a quantity of fuel fed with a gas if the modified lambda control deviation exceeds a predetermined threshold value.
2. The method as claimed in claim 1 , wherein the tank container is an activated carbon filter of the tank system.
3. The method as claimed in claim 1 , wherein a multiplicative correction value is determined via the engine characteristics map from a difference of the lambda set value and the lambda actual value.
4. The method as claimed in claim 3 , wherein the multiplicative correction value is multiplied with a relative deviation of lambda actual value and lambda set value.
5. The method as claimed in claim 4 , wherein the pseudo lambda control deviation is determined based upon the multiplication.
6. The method as claimed in claim 5 , wherein the relative deviation of lambda actual value and lambda set value is calculated as follows:
Relative deviation=1−(lambda set value)/(lambda actual value).
7. The method as claimed in claim 1 , wherein the pseudo lambda control deviation is set to a start value, if a difference between the lambda actual value and the lambda set value falls below a first predetermined value.
8. The method as claimed in claim 7 , wherein the multiplicative correction value increases the difference between the lambda actual value and the lambda set value if the difference exceeds a second predetermined value.
9. The method as claimed in claim 8 , wherein the modified lambda control deviation is corrected by a zero value, wherein the zero value corresponds to the modified lambda control deviation before an opening of the ventilation valve.
10. The method as claimed in claim 1 , wherein the injection correction determines an actual concentration value of a proportion of fuel contained in the gas based upon the modified lambda control deviation.
11. The method as claimed in claim 10 , wherein the injection correction is based on the current concentration for the injection correction if the threshold value is exceeded.
12. The method as claimed in claim 11 , wherein the lambda actual value is temporally smoothed.