Design Methodology of Camshaft Driven Charge Valves for Pneumatic Engine Starts
Moser, Michael M. Voser, Christoph Onder, Christopher H. Guzzella, Lino
Design Methodology of Camshaft Driven Charge Valves for Pneumatic Engine Starts - ene./feb. 2015 - 15 p. ; 179-194
Transcripción del resumen del autor: Idling losses constitute a significant amount of the fuel consumption of internal combustion engines. Therefore, shutting down the engine during idling phases can improve its overall efficiency. For driver acceptance a fast restart of the engine must be guaranteed. A fast engine start can be performed using a powerful electric starter and an appropriate battery which are found in hybrid electric vehicles, for example. However, these devices involve additional cost and weight. An alternative method is to use a tank with pressurized air that can be injected directly into the cylinders to start the engine pneumatically. In this paper, pneumatic engine starts using camshaft driven charge valves are discussed. A general methodology for an air-optimal charge valve design is presented which can deal with various requirements. The proposed design methodology is based on a process model representing pneumatic engine operation. A design example for a two-cylinder engine is shown, and the resulting optimized pneumatic start is experimentally verified on a test bench engine. The engine’s idling speed of 1200 rpm can be reached within 350 ms for an initial pressure in the air tank of 10 bar. A detailed system analysis highlights the characteristics of the optimal design found.
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Design Methodology of Camshaft Driven Charge Valves for Pneumatic Engine Starts - ene./feb. 2015 - 15 p. ; 179-194
Transcripción del resumen del autor: Idling losses constitute a significant amount of the fuel consumption of internal combustion engines. Therefore, shutting down the engine during idling phases can improve its overall efficiency. For driver acceptance a fast restart of the engine must be guaranteed. A fast engine start can be performed using a powerful electric starter and an appropriate battery which are found in hybrid electric vehicles, for example. However, these devices involve additional cost and weight. An alternative method is to use a tank with pressurized air that can be injected directly into the cylinders to start the engine pneumatically. In this paper, pneumatic engine starts using camshaft driven charge valves are discussed. A general methodology for an air-optimal charge valve design is presented which can deal with various requirements. The proposed design methodology is based on a process model representing pneumatic engine operation. A design example for a two-cylinder engine is shown, and the resulting optimized pneumatic start is experimentally verified on a test bench engine. The engine’s idling speed of 1200 rpm can be reached within 350 ms for an initial pressure in the air tank of 10 bar. A detailed system analysis highlights the characteristics of the optimal design found.
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