Implementation of Advanced Fuels and Combustion for Internal Combustion Engines

Track II: Transportation and BiofuelsIncludes audio file (19 min.)Advanced engine designs for transportation has shown significant reduction in engine-out emissions while simultaneously achieving gains in fuel efficiency by using Low Temperature Combustion (LTC) modes and feedback control of the combustion processes. The work of this group has considered the difficulties encountered in using these combustion modes through implementation of advanced control methodologies, novel sensor techniques as well as expanding usage of fuels such as bio-fuels and hydrogen. The methods used to obtain the lower combustion temperatures include lean mixtures and high levels of exhaust gas recirculation. For example, LTC modes such as Homogeneous Charge Compression Ignition (HCCI) and Partially Premixed Compression Ignition (PCCI) engines show real gains in reduced engine out emissions with improved efficiency. However, implementation of these advanced combustion modes presents combustion timing and stability issues due to stronger dependence of these advanced combustion modes on the physical and chemical properties of the fuel, inlet temperature, and inlet composition than traditional diffusion burning (“diesel” type) modes. Progress in these advanced combustion modes requires a “smart” engine capable of sensing heat release patterns and adjusting combustion system parameters. Hence collaborative work between several researchers at Missouri S&T are considering the required combustion analysis, nonlinear control, sensor development and fuel property issues surrounding the implementation of several LTC modes. Analysis methods currently considered are based on surface accelerations for use on both conventional and premixed auto-ignited combustion types that can robustly indicate combustion characteristics. Surface mount accelerometers are being used to indicate combustion characteristics needed for closed loop engine control but which have minimal structural influence. Acceleration frequency bands are being identified where the structural characteristics has the most influence (i.e. structure resonant modes), thereby allowing indication of other surface acceleration frequency bands which are minimally affected by the structure and more indicative of the combustion behavior. Active control necessitates an advanced control strategy such as adaptive neural networks which we have shown can function satisfactorily even when the dynamics of the engine combustion process are unknown. A near optimal nonlinear adaptive controller using Approximate Dynamic Programming (ADP), based on a phenomenological LTC engine model is being developed. The conceived controller would reduce cyclic variability in start-of-combustion, limit pressure rise rates and control to maximize efficiency through control of heat release pattern phasing. With advanced control algorithms, low-cost sensor technologies need to be developed before robust control of auto-ignited combustion can be achieved on a production scale. Interferometer based sensors packaged in small fiber optics are being developed for the high temperature and pressure combustion chamber environment with response times on the order of microseconds. Finally, advancing the application of advanced LTC modes to enable the use of bio-fuels or hydrogen has become increasingly important for energy security. Consequently, the distinct characteristics of hydrogen combustion in engines are being investigated using advanced simulation techniques to examine more efficient and cleaner operating strategies (e.g., dual-fuel operation)

Hydrogen Safety in Accidental Release Scenarios [abstract]

Only abstract of poster available.Track II: Transportation and BiofuelsWith the intensified energy and environmental concerns, hydrogen is considered to be one of the viable solutions to the increasing demands for clean and secure energy. The transition from fossil fuels to such technologies involves challenges that must be overcome for widespread public use/acceptance. Safety issues need to be fully addressed by developing proper codes and standards that are critical for the design and operation of hydrogen-powered systems. Fire safety of hydrogen applications is generally provided by experience from other traditional fuels whose properties are drastically different from those of hydrogen. As part of a broader project to establish the first hydrogen fueling station and hydrogen-powered commuter service in the state of Missouri, the transient behavior of hydrogen mixing and the associated flammability limits in air are investigated to support the fire safety and prevention guidelines. Advanced computer simulations are developed and utilized to gain a comprehensive understanding of the unsteady mixing, leakage, and flammability of hydrogen under simple and practical conditions. Different hydrogen accidental release scenarios were studied and compared with that of traditional fuels like methane and ethane. The observed complex temporal and spatial distributions of hydrogen demonstrate the fast formation of flammable zones. These results have implications in the safe and efficient use of hydrogen in various applications (e.g., fuel cells) as well as the ventilation of hydrogen accidental leakage in closed and partially closed environments (e.g., parking garage, storage facilities, road tunnel) and other supplementary infrastructure

Fuel Cell Policy Recommendations [abstract]

Only abstract of poster available.Track III: Energy InfrastructureIn its review of the Department of Energy's Research Development and Demonstration Plan for hydrogen, the National Academies recommended a study of lessons learned from technologies developed for stationary power systems. Thus, the motivation for this project is a study to identify the lessons learned from prior stationary power programs, including the most significant obstacles, how these obstacles have been approached, outcomes of the programs, and how this information can be used to meet objectives for distributed stationary power systems. To understand how to prepare for this future technology, this study is conducting a thorough investigation of past alternative stationary power projects to assess the opportunities for future stationary power efforts. Though the focus in on stationary (and portable) applications, the strategy considers the various trade-offs and opportunities by systematically incorporating considerations of both transportation and stationary sectors. Additionally, the strategy considers the integration of renewable systems with the existing power systems. This poster provides preliminary results and recommendations for early market transformation strategies for fuel cells, primarily related to hydrogen pathway technologies (production, delivery, and storage) and implementation of fuel cell technologies for distributed stationary power. Further, the lessons learned address environmental and safety concerns, including codes and standards, and education of key stakeholders