Method for internal combustion engine fuel injection computation based on fuel aging

Abstract

A method for the injection computation for an internal combustion engine, in particular for a gasoline range extender engine. This includes ascertaining an adaptation factor, which represents fuel aging, from a model of the fuel and a fuel outgassing via a tank vent and adaptation of a fuel injection quantity and/or a fuel injection time using the adaptation factor.

Claims

1. A method for fuel injection control for an internal combustion engine, comprising: ascertaining an adaptation factor, which represents an aging of fuel, from a model of the fuel and from fuel outgassing via a tank vent; and controlling, using the adaptation factor, at least one of a fuel injection quantity and a fuel injection time of injected fuel; wherein the model of the fuel aging uses as at least one input variable an influencing factor for taking into account ambient temperature fluctuation over time, and wherein the adaptation factor representing aging of fuel is determined additionally by multiplying factors representing a temperature of the internal combustion engine and a temperature of air drawn in through an intake manifold by the internal combustion engine, wherein a fuel aging is computed from an ambient temperature and a fuel mass released through a tank vent, wherein the model of fuel aging outputs a dimensionless factor of fuel aging which is multiplied by a dimensionless factor of an internal combustion engine temperature, which is ascertained from the temperature of the internal combustion engine, wherein a multiplication takes place by a dimensionless factor of intake air, which is ascertained from the temperature of air drawn in by the internal combustion engine through the intake manifold, wherein the adaptation factor has a value of 1 for unaged fuel, and increases with fuel age and outgassing through the tank vent, and wherein the engine is a range extender engine.

2. The method as recited in claim 1, wherein the model of the fuel uses as additional input variables a fuel tank filling level, a consumed fuel mass, a tanked fuel mass, and a tank filling time.

3. The method as recited in claim 1, wherein a fuel injection quantity of the range extender engine is adapted by multiplying it by the adaptation factor.

4. The method as recited in claim 1, wherein a fuel injection time is shifted to an earlier injection by an offset depending on the adaptation factor.

5. A non-transitory, computer readable medium storing a computer program, which is executable by a processor, comprising: a program code arrangement having program code for providing fuel injection control for an internal combustion engine, by performing the following: ascertaining an adaptation factor, which represents an aging of fuel, from a model of the fuel and from fuel outgassing via a tank vent; and controlling, using the adaptation factor, at least one of a fuel injection quantity and a fuel injection time of injected fuel; wherein the model of the fuel aging uses as at least one input variable an influencing factor for taking into account ambient temperature fluctuation over time, and wherein the adaptation factor representing aging of fuel is determined additionally by multiplying factors representing a temperature of the internal combustion engine and a temperature of air drawn in through an intake manifold by the internal combustion engine, wherein a fuel aging is computed from an ambient temperature and a fuel mass released through a tank vent, wherein the model of fuel aging outputs a dimensionless factor of fuel aging which is multiplied by a dimensionless factor of an internal combustion engine temperature, which is ascertained from the temperature of the internal combustion engine, wherein a multiplication takes place by a dimensionless factor of intake air, which is ascertained from the temperature of air drawn in by the internal combustion engine through the intake manifold, wherein the adaptation factor has a value of 1 for unaged fuel, and increases with fuel age and outgassing through the tank vent, and wherein the engine is a range extender engine.

6. The computer readable medium as recited in claim 5, wherein a fuel injection quantity of the range extender engine is adapted by multiplying it by the adaptation factor.

7. The computer readable medium as recited in claim 5, wherein a fuel injection time is shifted to an earlier injection by an offset depending on the adaptation factor.

8. A control unit to control a fuel injector of an internal combustion engine, comprising: an ascertaining arrangement to ascertain an adaptation factor, which represents aging of fuel, from a model of the fuel and from fuel outgassing via a tank vent; a controlling arrangement to control, using the adaptation factor, at least one of a fuel injection quantity and a fuel injection time of injected fuel; wherein the model of the fuel aging uses as at least one input variable an influencing factor for taking into account ambient temperature fluctuation over time, wherein the adaptation factor representing an aging of the fuel is determined by multiplying factors representing a temperature of the internal combustion engine and a temperature of air drawn in through an intake manifold by the internal combustion engine, wherein a fuel aging is computed from an ambient temperature and a fuel mass released through a tank vent, wherein the model of fuel aging outputs a dimensionless factor of fuel aging which is multiplied by a dimensionless factor of an internal combustion engine temperature, which is ascertained from the temperature of the internal combustion engine, wherein a multiplication takes place by a dimensionless factor of intake air, which is ascertained from the temperature of air drawn in by the internal combustion engine through the intake manifold, wherein the adaptation factor has a value of 1 for unaged fuel, and increases with fuel age and outgassing through the tank vent, and wherein the engine is a range extender engine.

9. The control unit as recited in claim 8, wherein a fuel injection quantity of the range extender engine is adapted by multiplying it by the adaptation factor.

10. The control unit as recited in claim 8, wherein a fuel injection time is shifted to an earlier injection by an offset depending on the adaptation factor.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) An exemplary embodiment of the present invention is illustrated in the FIGURE and explained in greater detail below.

(2) FIG. 1 shows a flow chart for ascertaining an adaptation factor in a method according to one specific embodiment of the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

(3) FIG. 1 schematically shows the sequence of a method for the injection computation for a gasoline range extender engine having an intake manifold gasoline injection according to one specific embodiment of the present invention. With the aid of a tank filling level sensor, a fuel tank filling level 11, a consumed fuel mass 12 and a tanked fuel mass 13 are ascertained. These variables are used together with a tank filling time 14 as input variables for a fuel model 2. An influencing factor 21 for taking into account a temperature fluctuation over time is ascertained from ambient temperature 15 and is used as an input variable for fuel model 2. Fuel model 2 and fuel outgassing 31 are used as input variables for a model for fuel aging 3. Fuel aging 3 is computed from ambient temperature 15 and a fuel mass 16 released through a tank vent. The model of fuel aging 3 outputs a dimensionless factor of fuel aging which is multiplied by a dimensionless factor of internal combustion engine temperature 41, which is ascertained from the temperature of internal combustion engine 17. In addition, a multiplication takes place by a dimensionless factor of intake air 42, which is ascertained from the temperature of air 18 drawn in by the internal combustion engine through an intake manifold. The multiplication by these three factors results in an adaptation factor 5. This adaptation factor 5 has a value of 1 for unaged fuel, and increases to a value of 1.1 with outgassing through the tank vent, for example.

(4) The fuel injection quantity of the range extender is adapted (represented by box 6 in FIG. 1) by multiplying it by this adaptation factor 5. Alternatively, the fuel injection time is shifted to an earlier injection by an offset depending on this adaptation factor 5. More reliable starting of the range extender engine may be ensured by the example method according to the present invention. Combustion misfiring or worsening of the exhaust gas values may be prevented by using this example method.