A critical review of cooling techniques in proton exchange membrane fuel cell stacks

Conversion of hydrocarbons and alcohols for fuel cells

Fuel conversion to hydrogen is an important part of most fuel cell systems. The paper describes the available technologies for conversion of hydrocarbons and alcohols. The endothermic steam reforming catalysts
 and processes as well as autothermal reforming are proven technologies. Recent developments include catalytic partial oxidation. The integration of the fuel processing with the fuel cell represents a task with requirements
 depending on each type of fuel cell and application. The automotive use of fuel cells is at present a special challenge. The optimum fuel for stationary plants
 is natural gas (if available), whereas light naphtha appears to be the choice for automotive use.

Since the beginning of railway electrification, power quality has been a main problem in railway networks because of their special characteristics. Many ways of power quality improvement have been investigated and applied to ac and dc traction systems through railway electrification history. This paper presents a perspective on power quality issues through railway electrification development and investigates the necessity of power quality and system requirements for appropriate power quality. Compensation strategies are classified and compared. This aims to provide a comprehensive perspective of the power quality issue in railway power/distribution networks for researchers and engineers working on railway electrification. Less than 100 research articles are referenced for researchers to obtain good background information.

Power Quality Issues in Railway Electrification: A Comprehensive Perspective

Review of methanol reforming-Cu-based catalysts, surface reaction mechanisms, and reaction schemes

A bipolar plate (2) for a high-temp. fuel cell stack includes at least two gas-carrying ducts (6) mutually separated from one another by means of a land (8). The land (8) is coated on its end-face (4) with a ceramic layer (10) which comprises an upper (14) and a lower (12) layer, in which the lower layer (12) has a greater bulk than the upper layer (14).

Bipolar plate arrangement for high-temp. fuel-cell stack

Force measurement arrangement comprises means (3) for applying a force and fixed counter means (4) that receive the applied force. A spring element (1) elastically transfers the force between the two parts, while a deflection sensor measures the movement of the force applying means. The spring element is mounted in a rotationally symmetric manner about the central axis of the force applying means and the deflection sensor is arranged radially within the spring means.

Force measurement arrangement, comprises a compact arrangement of force application bolt, force receiving base part, meander spring for force transfer between the two and a linear displacement sensor for the force application bolt

A method for controlling a piezoelectric actuator which displaces a control element of an injection valve includes the step of charging the actuator until a start voltage is reached. Subsequently, the actuator is discharged until a partial lifting voltage, which is maintained during a holding time, is reached. In the final step, the actuator is discharged until an off-load voltage is reached and a parameter which is dependent on the partial lifting voltage is used as a control variable. A desired value for the control variable is determined and the actuator is controlled in such a manner that the desired value of the control variable is maintained.

Method For Controlling A Piezoelectric Actuator And Control Unit For Controlling A Piezoelectric Actuator

Verfahren
zum Steuern eines piezoelektrischen Aktors, der ein Stellglied,
insbesondere eine Schaltnadel einer Pumpe-Duse-Einheit bewegt. Der Aktor wird
zuerst auf eine Startspannung aufgeladen. Anschliesend wird
der Aktor auf eine Teilhubspannung entladen, wobei die Teilhubspannung
eine Haltezeit gehalten wird. In einem letzten Schritt wird der
Aktor auf eine Ruhespannung entladen, wobei ein von der Teilhubspannung
abhangiger Parameter
als Steuergrose verwendet
wird. Es wird ein Sollwert fur
die Steuergrose festgelegt
und die Steuerung des Aktors in der Weise durchgefuhrt, dass
der Sollwert der Steuergrose eingehalten
wird.

Verfahren zum steuern eines piezoelektrischen aktors und steuereinheit zum steuern eines piezoelektrischen aktors

The arrangement distinguishes between frequency-modulated inductive sensor signals generated at a remote place and transmitted over signal conductors to an evaluation arrangement. The sensor signals are caused by eventual wheel influences, and are supplied to an input filter, by which they are prepared for the evaluation. A frequency-to-voltage converter (FSU1, FSU2) with at least one coupled trigger (T12, T22) is connected to the signal conductors (SK). The threshold of the trigger lies below or above a signal level which settles in when the sensor is not influenced and when no noise is present. The trigger responds to an under- or overstepping of the threshold value. The output signal of the trigger is combined by an AND function with the output signal of a further trigger (T13, T23) which is connected at least indirectly to the output of the input filter, and which responds when the value falls below its predetermined threshold.

Harald Schmidt

Papers

Bipolar plate arrangement for high-temp. fuel-cell stack

Force measurement arrangement, comprises a compact arrangement of force application bolt, force receiving base part, meander spring for force transfer between the two and a linear displacement sensor for the force application bolt

Method For Controlling A Piezoelectric Actuator And Control Unit For Controlling A Piezoelectric Actuator

Verfahren zum steuern eines piezoelektrischen aktors und steuereinheit zum steuern eines piezoelektrischen aktors

Axis counting arrangement for rail-bound vehicle