High Energy Dual Coil Ignition System for Gasoline Engines with EGR or lean combustion

Improved fuel economy and reduced emissions are driven by legislation as well as by customer demands. In order to achieve higher engine efficiency and enhanced combustion, different approaches as downsizing, turbo charging, direct injection, exhaust gas recirculation or higher air-fuel ratio are applied. All these approaches require higher ignition voltage and ignition energy. A Dual Coil Ignition System (DCI) can overcome the restrictions of a single spark system, since a DCI achieves a continuous, long-lasting spark with higher total energy by subsequently charging and discharging two ignition coils inside a single housing. In a first step, the DCI is used to analyze the behavior of the spark duration and the spark deflection in a pressure chamber depending on electrical set point, pressure and flow rate. In a second step, the benefits of the DCI compared to a standard transistor coil ignition system are shown by measurements on a 1.4L DI engine with 90kW and 200Nm on a test bench at different engine operation points. For a given engine running smoothness, the DCI achieves a higher EGR-rate and enables a leaner combustion with an increased air-fuel ratio. In summary, the DCI helps the combustion process to be more efficient with lower emissions.