Evaluating the Behavior of Carbureted Engines using a Fast Response Fuel Consumption Measurement Device with Minor Impact on Engine Characteristics

Meeting future legislative targets for SI engines by means of low cost technologies is a big challenge for engineers. Despite the use of simple and cost efficient components these engines have to fulfill customer requirements in terms of power and fuel economy, representing the most important selling arguments. Without the possibility of integrating modern technologies like fuel injection systems for mixture preparation instead of simple carburetors, it is very complex to find viable solutions that enable the achievement of these targets. A main key to improve emission behavior, fuel economy and performance on carbureted engines is to get an insight in the mixture preparation process, especially under transient conditions. Therefore, the Institute for Internal Combustion Engines and Thermodynamics of Graz University of Technology together with AVL Germany investigated possibilities to measure the fuel mass flow with a flexible, quick responding device that does not influence the carburetor itself. Comparisons of different fuel flow measurement tools on several engine applications were done to find out which one delivers the information required for advanced carburetor setup tasks in the best possible way. This should serve as a basis for future mixture preparation development on the test bench and especially for in-field optimization.