Daimler-benz Ag

Other

Daimler Chrysler Ag

Helmut Lorenz

Josef Sonntag

Karl-Ernst Noreikat

Gerald Hornburg

Wolfram Fleck

Thomas Klaiber

Andreas Gaulhofer

Andreas Schell

Klaus Keilhofer

Ludwig Vollmer

In a method for operating a load-dependent power-generating system which supplies electric energy to at least one electric drive motor in a vehicle, a performance setpoint value is determined for the electric drive motor from an accelerator pedal position, and a power request is made to the power-generating system before a torque request to the drive motor. Dynamic movement parameters of the accelerator pedal are also used to calculate the performance setpoint value.

Method for operating a load-dependent power-generating system in a vehicle

A DC/DC converter which can be operated alternately as a step-up converter in a first direction of energy flow and as a step-down converter in a second direction of energy flow is disclosed. Potential isolation between the low-voltage side and the high-voltage side of the converter is achieved by a magnetic compound unit, which has not only a transformer function but also an energy store function. The converter operates as a push-pull converter in both directions of energy flow. The DC/DC converter can be used for example in motor vehicles with an electric drive fed by fuel cells.

Bidirectional DC/DC converter with a step-up mode in one direction and a step-down mode in the other direction

An apparatus and method for starting a vehicle which is driven by an electric drive unit supplied with electrical energy from a fuel cell. A compressor is arranged in the feed line of the fuel cell for the oxidant mass flow and is driven by an electric motor supplied with voltage from the fuel cell itself. For the purpose of starting the fuel cell, a starter motor is provided for driving the compressor which is fed from a 12 V starter battery. In addition, a safety interrogation is initiated before starting the vehicle. The fuel cell is not run up to a prescribed no-load power with the aid of the starter motor until successful termination of the safety interrogation. The drive unit is then released after this no-load power has been reached.

Apparatus and method for starting a fuel cell vehicle

The invention provides a process for dynamically adjusting the power of an electric driving unit of a vehicle which is supplied with electric energy by a fuel cell, the power of the fuel cell or the provided fuel cell current being controlled by means of the supplied air volume flow. The air volume flow is adjusted by the rotational speed of a compressor, a desired rotational speed value being predetermined for the compressor based on an accelerator pedal demand. Simultaneously, based on the measured air flow volume, the actually available fuel cell current is determined and therefrom a corrected accelerator pedal demand is determined. During the starting operation, the accelerator pedal demand is supplied directly to the driving unit, whereas, at higher rotational speeds, it is limited by the corrected accelerator pedal demand.

Process for dynamically adjusting the power for a vehicle having a fuel

A method and an apparatus are provided for controlling the power of an electric drive unit in a vehicle. The drive unit is supplied with electrical energy by a fuel cell in the vehicle. On the basis of a power request which is determined from the accelerator pedal position, the air flow rate required to provide the set power from the fuel cell is calculated and set by controlling rotational speed of a compressor arranged in the air intake line to the fuel cell. To prevent the fuel cell from producing more electrical power than the drive unit can absorb, the drive unit acts limits the power request by emitting appropriate error messages. The set value for the power is fed to the drive unit and can be corrected such that the drive unit never demands more power than the amount of power instantaneously produced by the fuel cell to prevent fuel cell collapse.

Growing community of inventors

Unterensingen, Germany

Helmut Lorenz