Development and Demonstration of a Production-Intent Transient Plasma Ignition System for High Efficiency Natural Gas Engines

Increasing efficiency of heavy-duty natural gas engines with non-thermal plasma ignition

Transient Plasma Systems, Inc.


Torrance, CA

Recipient Location


Senate District


Assembly District



Amount Spent



Project Status

Project Result

The researchers improved on their initial design by increasing the frequency of pulses from 20 kHz to 100 kHz. The multi cylinder prototype underwent system level testing before being sent to Argonne National Laboratory. Unexpected issues due to electromagnetic interference were resolved with redesigns using custom electronics instead of off-the-shelf components. Without updating the engine fuel maps, the testing at Argonne National Lab on the ISX12N demonstrated stable operation at 22 percent EGR, greater than 2 percent improved brake thermal efficiency, 10 percent reduction of carbon monoxide emissions, and 30 percent reduction of NOx emissions. Further optimization of the fuel maps would enable additional efficiency gains. Test results were shared with engine manufacturers and Tier 1 suppliers. The final report is published on the CEC website.

View Final Report

The Issue

Spark-ignited natural gas engines are a promising alternative transportation technology to diesel engines for heavy-duty vehicles. Natural gas engines have the potential to achieve ultra-low NOx emissions, but current models are 10 percent less efficient than diesel engines. Natural gas engines can both lower emissions and increase efficiency by operating at higher exhaust gas recirculation dilution and boost pressure, but these conditions make it more difficult to consistently ignite natural gas using conventional spark ignition. Advanced ignition systems are potential enabling technologies for improving the efficiency of natural gas engines and their overall competitiveness against diesel.

Project Innovation

This project developed a production intent prototype of a non-thermal plasma ignition system that can reduce maintenance requirements, improve engine efficiency, and reduce emissions of heavy-duty on-road natural gas engines. The project builds on previous research work that validated the benefits of this technology in single cylinder test engines by focusing on developing a multi-cylinder system. The prototype was tested at Argonne National Laboratory across the operating range of a commercially available low NOx emission natural gas engine: the Cummins Westport ISX12N. The researchers evaluated the test results to determine immediate benefits as well as further opportunities to optimize the engine using the transient plasma ignition system.

Project Benefits

The non-thermal plasma ignition system uses multiple nanosecond-duration pulses of energy to ignite natural gas in an internal combustion engine. Unlike traditional spark plugs, this technology does not rely on a sustained high energy spark to ignite the fuel. The transient plasma ignition system has the potential to improve fuel efficiency, reduce NOx emissions, and increase spark plug lifetime compared to a conventional energy arc-spark system. The ignition system is intended as a drop-in replacement for standard ignition coil modules, allowing for simple engine integration and greater opportunities for near-term commercialization.

Greater Reliability


Transient plasma ignition does not rely on high-energy thermal ignition, reducing the impact of erosion and maintenance needs compared to conventional spark plugs.

Environmental & Public Health

Environmental Sustainability

The engine testing showed a 30 percent reduction in NOx emissions, 10 percent reduction and CO emissions, and 2 percent improvement in engine efficiency. Additional CO2 emission reductions are possible with fuel map optimization.

Key Project Members

Project Member

Dan Singleton



Argonne National Laboratory


Cummins Westport, Inc.


Match Partners


Southern California Gas Company (SoCalGas)


Cummins Westport, Inc.


Transient Plasma Systems, Inc.


Contact the Team