Fuel Injection Control

1 . A method for setting injection timing for injection of a fuel into a combustion chamber of a cylinder of an internal combustion engine, the method comprising:

determining a torque of the internal combustion engine;

determining a speed of the internal combustion engine;

determining a cylinder wall temperature of the cylinder;

selecting the injection timing based at least on the cylinder wall temperature, the torque, and the speed; and

controlling an injection of fuel into the combustion chamber using the selected injection timing.

2 . The method as claimed in claim 1 , further comprising:

determining

a piston crown temperature of the cylinder; and

adapting the selected injection timing based on the piston crown temperature.

3 . The method as claimed in claim 1 , wherein:

selecting the injection timing includes referring to a first characteristic map provided for the internal combustion engine in a first operating mode to identify

a first value of the first characteristic map based on the torque and the speed;

applying a weighting factor to the first value based on the cylinder wall temperature; and

using the weighted first value to select the injection timing.

4 . The method as claimed in claim 3 , wherein:

selecting the injection timing includes referring to a second characteristic map provided for the internal combustion engine in a second operating mode which differs from the first operating mode;

determining a second value of the second characteristic map based on the torque and the speed;

applying a second weighted factor to the second value based on the cylinder wall temperature; and

using the weighted second value to select the injection timing.

5 . The method as claimed in claim 4 , wherein:

the first characteristic map corresponds to a normal operating mode; and

the second characteristic map corresponds to a load alteration of the internal combustion engine.

6 . The method as claimed in claim 1 , wherein determining the cylinder wall temperature using a predefined cylinder wall temperature model.

7 . The method as claimed in claim 6 , wherein the cylinder wall temperature model comprises a thermodynamic temperature model.

8 . The method as claimed in claim 6 , wherein the cylinder wall temperature represents dynamic cylinder wall temperature depending on a steady-state cylinder wall temperature.

9 . The method as claimed in claim 6 , wherein determining the cylinder wall temperature depends on an ascertained cylinder pressure, an ascertained swept volume of the cylinder, an ascertained air mass, and an ascertained indicated engine torque.

10 . The method as claimed in claim 6 , wherein determining the cylinder wall temperature depends on an ascertained exhaust-gas temperature.

11 . The method as claimed in claim 6 , wherein the cylinder wall temperature model depends on modular intermediate variables including: mean gas temperature in the cylinder chamber, indicated mean pressure of the cylinder, heat transfer coefficient in the combustion chamber, and steady-state cylinder wall temperature.

12 . An apparatus for controlling an internal combustion engine, the apparatus comprising:

a processing unit;

a program;

a data memory; and

a communication interface;

wherein the program, when executed by the processing unit, selects an injection time for a fuel injector based on a torque of the internal combustion engine, a speed of the internal combustion engine, a cylinder wall temperature of the cylinder; and

controls an injection of fuel into the combustion chamber using the selected injection timing.