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Equipping low cost two-wheelers with engine management systems (EMS) enables not only a reduction of emissions but also an improvement in fuel consumption and system robustness. These benefits are accompanied by initially higher system costs compared to carburetor systems. Therefore, intelligent software solutions are developed by Bosch, which enable a reduction of the necessary sensors for a port fuel injection system (PFI) and furthermore provide new possibilities for combustion control. One example for these intelligent software solutions is a model based evaluation of the engine speed. By use of the information contained in the engine speed signal, characteristic features like air charge, indicated mean effective pressure (imep) and combustion phasing are derivable. The present paper illustrates how these features could be used to reduce the system costs and to improve fuel consumption and system robustness.

Based on the fuel consumption analysis methods published on last year's SETC [1], we compared fuel economies of a typical 125cc production motorcycle equipped with either electronic (port) fuel injection (EFI/PFI) engine management system (EMS) or constant vacuum carburetor (Carb). In addition to earlier discussed PFI results, stationary engine map measurements of fuel consumption on an engine dynamometer (dyno) were conducted for the Carb engine. The powerful development tool of fuel consumption test cycle simulation uses these stationary engine dyno results to calculate fuel consumption of real transient vehicle operation. Here it was employed to assess economy of both fuel system configurations under different driving conditions. Besides the Indian Driving Cycle (IDC) and the World Motorcycle Test Cycle (WMTC), we investigated real world drive patterns typical for emerging markets in terms of a Bangalore urban cycle and a Malaysian suburban cycle.