Method for adapting variations in cylinder-selective injection quantities of a direct injection system and method for cylinder-selectively controlling injection

1. A method for adapting variations in cylinder-selective injection quantities of a direct injection system of an internal combustion engine with a plurality of cylinders, comprising the following steps:

a. injecting a prespecified cylinder-specific fuel quantity as a single quantity into the cylinder in accordance with a prespecified Lambda value,

b. determining a cylinder-selective Lambda value resulting from the single quantity injection of the prespecified cylinder-specific fuel quantity,

c. comparing the prespecified Lambda value with the cylinder-selective Lambda value determined from the single quantity injection of the prespecified cylinder-specific fuel quantity,

d. if the cylinder-selective Lambda value does not match the prespecified Lambda value, determining a first adaptation value for adapting the prespecified cylinder-specific fuel quantity, so that the cylinder-selective Lambda value resulting from the adapted cylinder-specific fuel quantity is synchronized with the prespecified Lambda value,

e. injecting into the cylinder the adapted cylinder-specific fuel quantity in the form of a plurality of fuel quantities, and determining a resulting second cylinder-selective Lambda value,

f. comparing the prespecified Lambda value with the second cylinder-selective Lambda value determined from the plural quantity injection of the adapted cylinder-specific fuel quantity, and

g. if the second cylinder-selective Lambda value does not match the prespecified Lambda value, determining a second adaptation value for further adapting the adapted cylinder-specific fuel quantity, so that the cylinder-selective Lambda value resulting from the further adapted cylinder-specific fuel quantity is synchronized with the prespecified Lambda value.

2. The adaptation method according to claim 1 , wherein the first adaptation value is a factorial adaptation value and the second adaptation value is an additive adaptation value.

3. The adaptation method according to claim 1 , wherein the injection only takes place if the internal combustion engine is in a practically constant operating state, so that comparability between single and multiple injection is guaranteed.

4. The adaptation method according to claim 1 , wherein the plurality of injection quantities consists of a main quantity and at least one small quantity less than the main quantity.

5. The adaptation method according to claim 1 , wherein the first and the second adaptation values are determined in the average load range of the internal combustion engine.

6. The adaptation method according to claim 5 , wherein the second adaptation value is determined in the mid load range and then applied in the lower load range of the internal combustion engine on injection of a plurality of injection quantities.

7. A method for cylinder-selective injection control in an internal combustion engine with injection system, comprising the following steps:

a. determining a first adaptation value for adapting a prespecified cylinder-specific fuel quantity to inject into a cylinder in the form of a single quantity in order to achieve a prespecified Lambda value,

b. determining a second adaptation value for adapting the prespecified cylinder-specific fuel quantity to inject into the cylinder in the form of plural quantities in order to achieve the prespecified Lambda value,

c. adapting the prespecified cylinder-specific fuel quantity with both the first and second adaptation values, before the fuel quantity is injected in the form of a plurality of fuel quantities,

d. adapting the prespecified cylinder-specific fuel quantity with the second adaptation value, before the fuel quantity is injected in a lower load and speed range in the form of a single fuel quantity, and

e. adapting the prespecified cylinder-specific fuel quantity with the first adaptation value, but not the second adaptation value, before the fuel quantity is injected in a range other then the lower load and speed range in the form of a single fuel quantity.

8. A device for adapting variations in cylinder-selective injection quantities of a direct injection system of an internal combustion engine with a plurality of cylinders, comprising:

a. means for injecting a prespecified cylinder-specific fuel quantity as a single quantity into the cylinder in accordance with a prespecified Lambda value,

b. means for determining a cylinder-selective Lambda value resulting from the single quantity injection of the prespecified cylinder-specific fuel quantity,

c. means for comparing the prespecified Lambda value with the cylinder-selective Lambda value determined from the single quantity injection of the prespecified cylinder-specific fuel quantity,

d. means for, if the cylinder-selective Lambda value does not match the prespecified Lambda value, determining a first adaptation value for adapting the prespecified cylinder-specific fuel quantity, so that the cylinder-selective Lambda value resulting from the adapted cylinder-specific fuel quantity is synchronized with the prespecified Lambda value,

e. means for injecting into the cylinder the adapted cylinder-specific fuel quantity in the form of a plurality of fuel quantities and determining a resulting second cylinder-selective Lambda value,

f. means for comparing the prespecified Lambda value with the second cylinder-selective Lambda value determined from the plural quantity injection of the adapted cylinder-specific fuel quantity, and

g. means for determining, if the second cylinder-selective Lambda value does not match the prespecified Lambda value, a second adaptation value for further adapting the adapted cylinder-specific fuel quantity, so that the cylinder-selective Lambda value resulting from the further adapted cylinder-specific fuel quantity is synchronized with the prespecified Lambda value.

9. The device according to claim 8 , wherein the first adaptation value is a factorial adaptation value and the second adaptation value is an additive adaptation value.

10. The device according to claim 8 , wherein the injection only takes place if the internal combustion engine is in a practically constant operating state, so that comparability between single and multiple injection is guaranteed.

11. The device according to claim 8 , wherein the plurality of injection quantities consists of a main quantity and at least one small quantity less than the main quantity.

12. The device according to claim 8 , wherein the first and the second adaptation values are determined in the average load range of the internal combustion engine.

13. The device according to claim 12 , wherein the second adaptation value determined in the mid load range is applied in the lower load range of the internal combustion engine on injection of a plurality of injection quantities.