Investigation on the flame characteristics in a PCCI engine using endoscope system with micro-cassegrain

Diesel engines are most frequently used in vehicles because of their high efficiency and durability. However, nitrogen oxide (NOx) and particulate matter (PM) from diesel engines are became problem. Recently, the premixed charged compression ignition (PCCI) technique has been studied specifically to reduce NOx and PM emissions simultaneously. While the PCCI engine has the advantage of reducing NOx and PM emissions, control of the combustion phase is difficult. Therefore, it is very important to understand the flame developing process and heat release pattern in a real PCCI engine. However, most research into the characteristics of PCCI combustion has used an optical access engine. This paper describes the combustion characteristics obtained using a micro-Cassegrain sensor and discusses how the sensor can be used to directly detect the flame characteristics for future control of PCCI combustion. From this research, the differences of flame characteristics between PCCI engine and conventional diesel engine were clarified.