Effect of discharge current and discharge duration on the discharge channel behavior and early flame formation

Abstract

In recent years, advanced combustion technologies, such as highly dilute and highly boosted technologies were employed in the internal combustion engine to improve the fuel economy and reduce exhaust emissions. However, there are still many challenges in these advanced combustion technologies for the purpose of ignition control. Developing a next-generation spark ignition system is strongly required for the spark-ignition engine. In this study, three types of ignition coils were used to understand the impact of different ignition strategies on discharge channel stretching and shortening behaviors. A high-speed infrared imaging and a high-speed direct photography method were used to capture the images simultaneously to investigate the influence of discharge channel behaviors on the initial flame formation. Results show that the discharge current is the main factor affecting the discharge channel stretching as compared with the discharge duration. Short-cut and restrike are two kinds of discharge channel shortening behaviors that affect early flame overlap and growth, short-cut shortening behavior is better than restrike shortening behavior for the flame development and enlarges the early flame during the discharge duration.

Keywords

• discharge characteristic
• simultaneous visualization
• discharge behavior
• early flame formation