Patent ID: 7826960

Claim:
A method for controlling an internal combustion engine having an engine block having a cylinder, a crankshaft arranged in the block, a cylinder head arranged on the block opposite the crank shaft, a piston arranged in the cylinder and connected to the crankshaft, a combustion chamber defined in the cylinder of the block and between the piston and the cylinder head, an exhaust manifold in communication with the combustion chamber as a function of the position of a gas exhaust valve, and a cylinder pressure sensor that detects a pressure in the combustion chamber, the method comprising: determining a polytropic exponent as a function of a plurality of measured values of the pressure in the combustion chamber registered during a power stroke of the cylinder once an air and fuel mixture contained in the cylinder has been burned and before the gas exhaust valve opens; determining a first exhaust gas temperature that is characteristic of the temperature of the exhaust gas before the gas exhaust valve opens; determining a second exhaust gas temperature that is characteristic of the temperature of the exhaust gas remaining in the combustion chamber of the cylinder after the gas exhaust valve closes, wherein the second exhaust gas temperature is determined as a function of: the first exhaust gas temperature, a pressure in the combustion chamber associated with the first exhaust gas temperature, a pressure in the combustion chamber after the gas exhaust valve has closed, and the polytropic exponent; and generating an actuation signal for controlling an actuating member of the internal combustion engine as a function of the second exhaust gas temperature.