Method for controlling an internal combustion engine having a lambda regulation
The aim of the inventive method is to improve the emission values of an internal combustion engine during idling following a cold start. Said aim is achieved by inferring an adaptive value for the required fuel quantity from a characteristic curve in accordance with the temperature of the internal combustion engine and verifying during continuous lambda regulation whether predetermined adaptation conditions are met. If so, an adaptive value is determined from the parameters of the lambda regulator and the characteristic curve is adjusted according the newly determined adaptive value and the measured temperature of the internal combustion engine.
1. A method of controlling an internal combustion engine having a lambda control, the method comprising:
determining if predefined activation conditions are met upon starting the combustion engine by executing a first check procedure;
measuring an internal temperature of the combustion engine and determining an adaptive value using a characteristic curve for calculating a fuel mixture based on the measured internal temperature, if the first check procedure is positive, the characteristic curve including a progression of the adaptive value relative to a progression of the internal temperature;
determining if predefined adaptation conditions are met while the lambda control is in operation by executing a second check procedure; and
determining an updated adaptive value using at least one control parameter of the lambda control and adjusting the characteristic curve using the updated adaptive value and the measured internal temperature, if the second check procedure is positive, and maintaining the unadjusted characteristic curve, if the second check procedure is negative, wherein the updated adaptive value is weighted by a weighting parameter during each combustion cycle until the lambda control is in effect.
2. The method according to claim 1 , wherein the activation conditions include the conditions that the internal combustion engine has been started at a temperature below a predefined temperature, and that the internal combustion engine is idling.
3. The method according to claim 1 , wherein the adaptation conditions include the condition that the internal combustion engine is idling.
4. The method according to claim 1 , wherein the adaptive value is calculated using at least one robust control parameter of the lambda control.
5. The method according to claim 4 , wherein the robust control parameter is determined from at least one of a plurality of control parameters of the lambda control after a current value of the at least one control parameters has completed transient oscillation.
6. The method according to claim 4 , wherein the robust control parameter is determined from at least one of a plurality of control parameters of the lambda control after the lambda control has been operating for at least a predefined minimum operating period.
7. The method according to claims 3 , wherein the at least one control parameter of the lambda control is an integral portion included in the lambda control.
8. The method according to claim 4 , wherein determining the updated adaptive value is further based on at least one previously updated adaptive value.
9. The method according to claim 2 , wherein the weighting parameter is decreased during each combustion cycle following a preceding combustion cycle.