Improved Engine Data Acquisition System and Interface to Enable Experimentation With Emerging Alternative Fuels in a Spark-Ignited CFR Engine

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Abstract Existing engine facilities often build upon legacy hardware and assumptions that were once state-of-the-art, but have since become less relevant or even outdated in the face of new research challenges facing the community today. Often, assumptions and simplifications to experimentation or analysis, once necessary to be made due to the computational limitations of the hardware at the time of initial development, are carried forward. These legacy elements can potentially limit the effectiveness of accurately describing key parameters or metrics before, during or post experimentation. The behavior of novel fuels is also not always fully understood, which highlights the need for tools to guide the design of the experimental matrix to avoid unexpected and potentially dangerous outcomes. Determining these key and critical experimentation parameters places additional strain on researchers during both the dry-lab (pre-experimentation), experimentation, and data post-processing phases, which in turn reduces the overall efficiency of the experimental process. With these factors in mind, this manuscript details the conversion of an existing spark-ignited single-cylinder Cooperative Fuel Research (CFR) engine, typically in-service at industrial plants for fuel octane testing or reserved for educational and light-duty research tasks, to a test cell equipped to handle a variety of different emerging alternative fuels. Specifically, modifications to the in-house LabVIEW program and data acquisition system are detailed, with emphasis on providing additional tools to aid in the expediency and more importantly assist in the safety during experiments. This includes the conversion of the existing CFR testing facility from a single liquid or single gaseous fuel capable system to a multi-fuel compatible system, complete with on-the-fly calculations of mass, energy, and volume fractions of existing fuel blends, increased low-speed sampling rates, and a calculating tool to determine scalar quantities required to command fuel flow set-points for a given blend at a particular equivalence ratio and airflow set-point (throttle). Additional factors, such as sensor selection and communication, are discussed with an emphasis on reducing experimental uncertainty. Overall, this work provides insights into possible adjustments and considerations when upgrading existing experimental setups to accommodate emerging alternative fuel use.