A comprehensive investigation of injection strategies for improving diesel engine combustion under cold start development

Abstract

Starting at cold temperatures ranging from -30°C to 0°C has been a concern for all diesel engines, especially for future diesel engines that need to meet tighter carbon emission standards. Combustion instability and increasing smoke emissions are rising concerns during the cold start of diesel engines. Cold ambient conditions cause long cranking periods or complete misfire events in diesel engines; therefore, they produce a large proportion of pollutants within the cylinder due to incomplete combustion. In this study, a comprehensive investigation of multiple injection strategies was conducted under cold-start conditions to identify an optimal injection strategy that improves diesel combustion stability, cold-startup performance, and decreases white smoke emissions at cold ambient temperatures. This study found that cold start-up performance can be improved by eliminating misfire and lowering time to clean up white smoke with a three-injection strategy (two pilots and one main injection, simply named Pilot-Pilot-Main).