Method for the correction of a fuel quantity injected by means of a fuel injection device during operation of an internal combustion engine
A method for correcting a fuel quantity injected by a fuel injection device during operation of an internal combustion engine, including: determining an air heat characteristic variable, on which an air heat stream fed to a combustion chamber of the engine functionally depends; determining an exhaust heat characteristic variable, on which an exhaust heat stream discharged from the combustion chamber functionally depends; determining a heat distribution factor, which specifies a fraction of the exhaust heat stream reduced by the air heat stream in relation to a heat stream fed with the injected fuel to the combustion chamber; calculating a fuel mass fed to the engine from the air heat characteristic variable, the exhaust heat characteristic variable and the heat distribution factor; calculating a comparison variable by comparing the calculated fuel mass with a fuel mass setpoint value and adapting actuation of the fuel injection device depending on the comparison variable.
1. A method for correcting a fuel quantity injected by a fuel injection device during operation of an internal combustion engine, comprising the steps of:
determining at least one characteristic air heat variable, on which an air heat flow supplied to at least one combustion chamber of the internal combustion engine functionally depends;
determining at least one characteristic exhaust heat variable, on which an exhaust gas heat flow discharged by the at least one combustion chamber functionally depends;
determining a heat distribution factor that represents the exhaust heat flow minus the air heat flow divided by heat flow supplied by a mass flow of the injected fuel to the at least one combustion chamber;
calculating a fuel mass supplied to the internal combustion engine from the at least one characteristic air heat variable, the at least one characteristic exhaust heat variable, and the heat distribution factor; and
calculating a comparison variable by comparing the calculated fuel mass with a desired fuel mass value and adjusting actuation of the fuel injection device as a function of a value of the comparison variable, including calculating a quotient as the comparison variable from the calculated fuel mass and the desired fuel mass value and adjusting the actuation of the fuel injection device only when the quotient has a value of greater than one.
2. The method according to claim 1 , including determining a first characteristic air heat variable by measuring combustion air temperature as a temperature of an air mass flow supplied to the at least one combustion chamber.
3. The method according to claim 2 , including determining a second characteristic air heat variable by measuring combustion air pressure as a pressure of the air mass flow supplied to the at least one combustion chamber.
4. The method according to claim 1 , including determining a characteristic exhaust heat variable by measuring exhaust gas temperature as a temperature of an exhaust mass flow being discharged from the at least one combustion chamber.
5. The method according to claim 3 , including calculating the air mass flow from the first and second characteristic air heat variables under consideration of a correction factor.
6. The method according to claim 1 , including calculating a quotient as the comparison variable from the calculated fuel mass and the desired fuel mass value.
7. The method according to claim 1 , including determining the desired fuel mass value as a function of current rotational speed and the current nominal torque of the internal combustion engine.
8. The method according to claim 7 , wherein the desired fuel mass is taken from an engine map.
9. The method according to claim 1 , including adjusting the desired fuel mass value a single time with respect to an operating altitude and/or an operating temperature of the internal combustion engine upon initialization of the method.
10. The method according to claim 5 , including determining the heat distribution factor and/or the correction factor as a function of the at least one characteristic air heat variable.
11. The method according to claim 1 , including carrying out the method at only one operating point of the internal combustion engine at which the internal combustion engine is delivering maximum torque.
12. The method according to claim 5 , including carrying out the method at least at a few different load points, wherein the heat distribution factor, the correction factor, and the desired fuel mass value are selected as a function of a current load point.
13. The method according to claim 12 , including carrying out the method over an entire operating range of the internal combustion engine.
14. The method according to claim 1 , including selecting the desired fuel mass value as a function of the at least one characteristic air heat variable and/or as a function of a current operating altitude of the internal combustion engine.