<p>Since measurements in engine test cells are closely coupled with high costs it is of interest to use physically interpretable engine models instead of engine maps. Such engine models can also be used to do off-line tests of how new or altered components affects engine performance.</p><p>In the thesis an existing mean value engine model will be extended with a model of a compressor bypass valve. A controller for that valve will also be developed. The purpose with that controller is to save torque and boost pressure but at the same time avoid having the compressor entering surge during fast closing transients in the throttle position.</p><p>Both the extension and controller is successfully developed and implemented. The extension lowers the pressure after the compressor and increases the pressure before the compressor when the bypass valve is being opened and the controller shows better results in simulations than the controller used in the research lab. By using the proposed controller, as much as 5 percent higher torque can be achieved in simulations.</p><p>Finally there is a discussion on wastegate control alternatives and the use of TOMOC for optimization of wastegate control.</p>

Since measurements in engine test cells are closely coupled with high costs it is of interest to use physically interpretable engine models instead of engine maps. Such engine models can also be used to do off-line tests of how new or altered components affects engine performance. In the thesis an existing mean value engine model will be extended with a model of a compressor bypass valve. A controller for that valve will also be developed. The purpose with that controller is to save torque and boost pressure but at the same time avoid having the compressor entering surge during fast closing transients in the throttle position. Both the extension and controller is successfully developed and implemented. The extension lowers the pressure after the compressor and increases the pressure before the compressor when the bypass valve is being opened and the controller shows better results in simulations than the controller used in the research lab. By using the proposed controller, as much as 5 percent higher torque can be achieved in simulations. Finally there is a discussion on wastegate control alternatives and the use of TOMOC for optimization of wastegate control.

Properly inerting a fuel cell is an essential function for the safety and durability of the product. DAM designs and produces a bypass valve to effectively inert the fuel cell while maintaining the oxidant gas flow in the compressor. The system provides a short closing and opening response time less than 100 ms, while consuming very little energy. In addition to cutting off the oxidant gas supply, the valve can be used to drain the fuel cell, optimize the shutdown and startup cycles, and even optimize the inerting of the fuel cell through the hydrogen circuit. DAM has already produced valve prototypes in diameters 16 mm and 50 mm which are currently in the test phase with first successful results, and whose functions can be extended with a position sensor or heating system. / Die geeignete Inertisierung einer Brennstoffzelle ist eine wesentliche Funktion für die Sicherheit und Lebensdauer des Produkts. DAM entwickelt und produziert ein Bypass-Ventil, das die Brennstoffzelle effektiv inertisiert und gleichzeitig den Oxidationsmittel-Gasstrom im Kompressor aufrechterhält. Das System bietet eine kurze Schließ- und Öffnungszeit von weniger als 100 ms und verbraucht dabei sehr wenig Energie. Neben der Unterbrechung der Oxidationsgaszufuhr kann das Ventil auch zum Entleeren der Brennstoffzelle, zur Optimierung der Abschalt- und Anfahrzyklen und sogar zur Optimierung der Inertisierung der Brennstoffzelle durch den Wasserstoffkreislauf eingesetzt werden. DAM hat bereits Ventilprototypen in den Durchmessern 16 mm und 50 mm hergestellt, die sich derzeit mit ersten Erfolgen in der Testphase befinden und deren Funktionen durch einen Positionssensor oder ein Heizsystem erweitert werden können.