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One-dimensional (1D) engine simulation packages are limited in modeling flows through an adverse pressure gradient where boundary layer separation is more likely to occur, as in the case of the diffuser part of the restrictor. The restrictor modeling difficulty usually manifests itself as an engine model that consumes a lot of effort (both computational and from the user) in the modeling of the restrictor. The approach sought in this work was to provide a flow vs pressure drop dependency to the code such that it does not consume too much effort in the analysis of the restrictor. This approach is similar to that used for the valve flow, where a look up table is typically provided for determining the flow. Experimentally determined flow measurements on a thin-plate orifice, a short restrictor and a long restrictor are presented and discussed. The developed model gave excellent results in an acyclic steady-state simulation and is being integrated in the full engine model.

The Formula SAE® rules require the use of a 20mm intake restrictor. The presence of the restrictor necessitates the design or retuning of fuel and spark strategies that, in turn require the use of a programmable engine control unit (ECU). This paper describes a process used to establish the fuel and spark strategies for a standard production motorcycle engine operating with a restricted air intake. Honda 600cc engines were controlled by three different ECUs: a Haltech, DTA and an “in-house” ECU. Simple calculations of injection duration are suggested to provide a baseline fuel map from which the engine could be started, and then fuel maps are tuned by experiment. Similar baseline numbers for ignition timing are given.

Motivated by experiences in the Formula SAE® competition, an engine control unit (ECU) was designed, developed and tested at Oakland University. A systems approach was taken in which the designs of the electronic architecture and software were driven by the mechanical requirements and operational needs of the engine, and by the need for dynamometer testing and tuning functions. An ECU, powered by a 68HC12 microcontroller was developed, including a four-layer circuit board designed for EMC. A GUI was written with Visual C++® for communication with a personal computer (PC). The ECU was systematically tested with an engine simulator, a 2L Ford engine and a 600cc Honda engine, and finally in Oakland's 2004 FSAE vehicle.