Daimler Chrysler Ag

Daimler-benz Ag

Roland Bischoff

Hermann Hiereth

Helmut Daudel

Guenter Fleckenstein

An exhaust gas turbocharger with a variable turbine geometry can be adjusted in the fired engine operation by an automatic turbine controller to a definable desired supercharging pressure in the intake port. In the braking operation, the turbocharger can be adjusted by an engine braking system with an automatic braking controller as a function of operating parameters of the internal-combustion engine into a ram position which increases the pressure in the exhaust gas system. A change-over element is provided for the change-over between the engine braking system and the automatic turbine controller. To make the exhaust gas turbocharger variable, the automatic turbine controller and the engine braking system each have a modular design and a separate construction. A manual braking signal to the engine braking system, can be generated in a manually adjustable brake operating device. A change-over element is provided for changing over between the automatic braking controller and the brake operating device.

Exhaust gas turbocharger with a variable turbine geometry

When an internal combustion engine supercharged by way of an exhaust-driven turbocharger is operated, compressed charge air is diverted as a function of the operating point of the internal combustion engine, by opening a shutoff valve in an overflow duct, out of a charge air duct leading to the internal combustion engine into an exhaust gas duct to the turbine of the exhaust-driven turbocharger in the presence of a driving pressure drop. In order to optimize supercharging performance over the entire operating characteristics diagram of the internal combustion engine, and decrease the exhaust emissions of the internal combustion engine, provision is made for the overflow duct to be enabled as necessary, for the recirculation of exhaust gas into the charge air duct, when a pressure drop driving toward the charge air duct is present.

Method for operating a supercharged internal combustion engine

In a method of controlling the charge air mass flow of an internal combustion engine having an exhaust gas turbocharger with adjustable turbine geometry and a control unit for controlling the operation of the turbocharger, the intake air and exhaust gas pressures are determined and a corresponding differential pressure value is generated which is compared with a desired differential pressure value for generating a control signal on the basis of which the turbine geometry is adjusted and, during instationary engine operation when an increased engine load is required, the turbine geometry adjustment is modified so as to reduce the turbine inlet flow cross-section to thereby increase the engine charge air pressure.

Method of controlling the charge air mass flow of a supercharged

A method for controlling a variable turbine geometry of an exhaust gas turbocharger which supercharges an internal combustion engine for driving a motor vehicle. The turbine geometry is set as a function of the operating load of the internal combustion engine between the opening position in idling and the closed position in full load operation. The turbine geometry is brought into an operating position predetermined for the prevailing load point. To improve the non-steady-state operating performance of the exhaust gas turbocharger and the internal combustion engine, in particular during long acceleration phases of the motor vehicle, the turbine geometry is guided during a switching pause for changing gear levels of the motor vehicle into a switching pause position which is independent of the operating load. In the switching pause position a reduced flow cross section of the turbine for the exhaust gas stream is set. This prevents a drop in supercharger rotation speed during the switching pause and the related delay in buildup of the torque and boost pressure of the internal combustion engine.

Method of controlling a VTG exhaust gas turbocharger

In a process for adjusting an exhaust gas turbocharger having a variable turbine geometry in the engine braking operation, engine operating parameters are measured for determining an actuating signal influencing the position of the turbine geometry. In order to provide a brake performance maximum for all rotational speed ranges of the engine, the charging pressure in the intake pipes and the exhaust gas counterpressure in the exhaust gas pipes are measured as engine operating parameters in front of the exhaust gas turbocharger, a total pressure is determined as the sum of the charging pressure and the exhaust gas counterpressure, and the turbine geometry is adjusted to such an extent that the total pressure corresponds to a maximal pressure.

Process and braking arrangement for an exhaust gas turbocharger having a

In a method of controlling the charge air mass flow of an internal combustion engine having an exhaust gas turbocharger with adjustable turbine inlet guide vanes during dynamic operation of the engine from one stationary operating state with a given engine power output to another stationary engine operating state with a greater engine power output, the flow guide vanes are first moved to a closing position providing a minimum flow cross-section and, after a certain engine operating parameter reaches a certain control value, the guide vanes are opened at a rate depending on the charge air pressure in the intake duct of the engine to a final opening position corresponding to the other stationary engine operating state.

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Pluederhausen, Germany

Roland Bischoff