Daimler Chrysler Ag

Christian Barba

Martin Dietz

Guenter Moll

Gunter Moll

Benjamin Müller

Joachim Zeger

In a method for limiting a boost pressure of an internal combustion engine which is supercharged by the compressor of an exhaust gas turbocharger including a control unit in which a desired boost pressure value is compared with a limiting value and when the desired boost pressure value exceeds the limiting value, the boost pressure is limited to the limiting value, and the limiting value is determined by a simulation model in the form of a group of a characteristic curves established as a function of an existing operating state of the internal combustion engine, a temperature, a pressure (p), and a air mass flow rate which occur upstream of a compressor of the exhaust gas turbocharger.

Method for limiting a boost pressure

In a method for determining the exhaust-gas recirculation quantity for an internal combustion engine having exhaust-gas recirculation, a basic quantity of a gas mixture inducted into the engine combustion chamber(s) is determined in advance, as well as a basic pressure and/or a basic temperature of the gas mixture for at least one predefinable basic state of the combustion engine at deactivated exhaust-gas recirculation is ascertained. With the engine running, pressure and/or temperature of the inducted gas mixture are/is then determined for the current engine state at activated exhaust-gas recirculation. The currently inducted gas-mixture quantity as the basic quantity is then corrected by at least the ratio of current pressure to basic pressure of the gas mixture and/or the ratio of basic temperature to current temperature of the gas mixture. Furthermore, a fresh-gas portion of the inducted gas mixture for the current engine state is ascertained, whereupon the current exhaust-gas recirculation quantity is determined on the basis of the difference between the ascertained current gas-mixture quantity and the ascertained fresh-gas portion. The method may used in connection with diesel engines of motor vehicles, for example.

Method for determining the exhaust-gas recirculation quantity

In a method for determination of a change in volumetric efficiency for an internal combustion engine, a reference volumetric efficiency is determined in advance. A first actual volumetric efficiency value which corresponds to a sensor error, is then determined at a first measurement point in a first rotational speed range in which a change in the flow losses in an intake tract has only a minor effect on the volumetric efficiency. A second actual volumetric efficiency value is determined at a second measurement point in a second rotational speed range that is greater than the first rotational speed range. The second actual volumetric efficiency value is corrected by means of the first actual volumetric efficiency value, and the change in volumetric efficiency is determined from the reference volumetric efficiency and the corrected second actual volumetric efficiency.

Method for determining a change in air consumption for a combustion engine

In a method of determining the quantity of exhaust gas recirculation for an internal combustion engine having exhaust gas recirculation, the exhaust gas recirculation quantity (r, m) is determined from an exhaust gas temperature (T), a fresh gas temperature (T), a fresh gas quantity (m) and/or a volumetric efficiency (&#x3b7;). The fresh gas temperature (T) is determined by a fresh gas temperature model () which is adaptively adjusted in response to influencing parameters relevant to the fresh gas temperature.

Method for determining an exhaust gas recirculation quantity for an internal combustion engine provided with exhaust gas recirculation

In a method for determining an exhaust gas recirculation amount for an internal combustion engine having a cylinder with an intake duct and an exhaust duct, wherein an outer exhaust recirculation amount is determined from an exhaust gas temperature, a fresh gas temperature, a fresh gas amount and an inner exhaust gas recirculation amount, and wherein the inner exhaust gas recirculation amount takes the combustion gas amount into consideration which during a charge change remains in the combustion chamber of the internal combustion engine.

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Fellbach, Germany

Christian Barba