Fundamental Investigations on the Boost Pressure Control System of Charged Aircraft Engines in the Aviation Class ELA1 / Approved Systems Versus New Solutions 2012-32-0048
Aircraft engines in the (ELA1) category, with a maximum power of up to 100kW, are characterized by a verified state of the art technology. New developments of engine technologies and control methods are very slowly being introduced into this engine segment. This trend is based on the fact that new technologies implemented in aircraft engines must be thoroughly certified and validated in a very complex and documented procedure.
For this reason, most of the engines in this class are equipped with a carburetor as an air/fuel mixture preparation system. Moreover, naturally aspirated spark ignited engines are widely used in the aircraft category, with a take-off weight of up to 1000kg.
The adaptation to a fuel injection system with an additionally charged engine operation mode results on the one hand, in considerably higher complexity and operational/functional risk and, on the other hand, in a significant improvement of the air/fuel mixture rate as well as better engine operation when increasing altitude. In particular, the interaction between the air/fuel mixture preparation and air mass control via boost pressure may be critical, with respect to required components and software modules, as each additional and modified part, when deviating from the certified status, requires additional effort in complex documentation and certification.
The use of an electronic engine control unit (ECU) enables the integration of the function of the boost pressure control. This is state of the art in automotive applications. To accommodate the principle of redundancy of aircraft engines and to be able to use approved components, the layout of the boost pressure control module, as an external boost pressure control unit (TCU), is required.
This publication introduces fundamental investigations into controlling boost pressure and engine parameters of charged aircraft engines. Experimental investigations consist of stationary and transient test runs, focusing on the two-way influence of the control loops of ECU and TCU. The suitability of an external boost pressure control, in combination with an electronic engine control system, is finally discussed.
Citation: Stelzl, R., Kirchberger, R., Schmidt, S., Dopona, M. et al., "Fundamental Investigations on the Boost Pressure Control System of Charged Aircraft Engines in the Aviation Class ELA1 / Approved Systems Versus New Solutions," SAE Technical Paper 2012-32-0048, 2012, https://doi.org/10.4271/2012-32-0048. Download Citation
Reinhard Stelzl, Roland Kirchberger, Stephan Schmidt, Michael Dopona, Wolfgang Wukisiewitsch, Nigel Foxhall
Graz University of Technology, BRP-Powertrain GmbH & Co KG
2012 Small Engine Technology Conference & Exhibition