Advanced Plasma Ignition Systems for Class 3-8 Natural Gas Engines

Gas Technology Institute, Enerpulse, and Ricardo demonstrated that two advanced, high-energy ignition systems are capable of effectively and efficiently igniting homogeneous mixtures of natural gas fuel and air in a heavy-duty natural gas engine. The purpose of testing these ignition systems is to demonstrate pathways to improving natural gas engine dilution tolerance, fuel economy, and emissions without sacrificing gas engine reliability relative to diesel engines. The two ignition systems both build upon the existing, commercially available Enerpulse n-PAC® high-energy ignition spark plugs.

The project team developed an initial design concept for a High Frequency Discharge Ignition System, which produces between two and eight charge-discharge cycles in an engine cylinder to enhance the ignition process. Although bench testing of the prototype system showed promise, further research is needed beyond this project to address challenges related to instability, electrode wear effects, engine optimization, and turbulent effects. The project team developed a second advanced ignition system, the Enerpulse Nano-Plasma C2 Discharge Ignition System, which delivers a single megawatt-level nanosecond pulse to ionize the arc gap followed by a variable energy pulsed power plasma discharge. The engine control unit regulates the spark power and duration, which will allow the engine manufacturer to balance the electrode wear with emissions, power, and fuel consumption through engine calibration. While there were constraints due to the experimental test set up, the C2 system operating in low power mode showed promise of extending a natural gas engine’s dilution tolerance, which can improve fuel economy and reduce emissions.