A Multi-cylinder Transient Plasma Ignition System for Increased Efficiency and Reduced Emissions in Gas Engines

California’s transportation sector accounted for 41 percent of the state’s greenhouse gas emissions at 418.2 million metric tons of carbon dioxide equivalent in 2019. Many vehicles — particularly those used in commerce, industry, and public transportation — are diesel fueled and cannot easily be modified to take advantage of the electrification option that avoids carbon dioxide emissions. Reducing greenhouse gas emissions from these vehicles is critical to achieving California’s climate change goals.

Gas engines, largely fueled by methane, emit significantly less carbon dioxide and almost no particulate matter for the same amount of energy output as diesel engines. Although some companies have developed ultra-low oxides of nitrogen emission gas engines for heavy-duty trucks, widespread adoption has not occurred.

Advanced ignition is a key enabler for the improved efficiency, maintenance, operational costs and reduced emissions necessary to compete with diesel alternatives and gain market acceptance. Transient Plasma Systems, Inc. (TPS) made significant progress in advanced ignition technology for heavy-duty gas engines. Combustion results from previous work have shown that this technology can improve brake thermal efficiency and reduce emissions by enabling stable operation at higher dilution levels. This project built on previous development work by focusing on electronics packaging, system integration with the main electronic control unit of the engine, operability improvements, and advancing the system toward commercialization. Specifically, custom device bonding, interconnect methods, and hermetic encapsulation were developed to increase performance, miniaturize size, and achieve a commercially viable form factor; closed-loop sense and control was developed to optimize energy draw and delivery to maximize plug durability; and improvements at the plug and cabling level were implemented to improve overall system performance. This project resulted in a compact multi-cylinder ignition system design based on receptively pulsed nanosecond discharges that is ready for commercial development with an engine technology supplier