Applicability of Fuel Injection Techniques for Modern Diesel Engines

Diesel engines with powerful and economical fuel economy are increasingly popular. The development of electronic fuel injection is an essential milestone in increasing the power and performance of diesel engines. The electronic fuel injection system aims to optimize the process of fuel injection into cylinders with the injection time controlled by the ECU, allowing high-pressure fuel injection regardless of the speed of the engine. However, fuel injection modes of ECU are complex and diverse strategies, often not published but are considered as the secret of engine companies. Therefore, it is essential to study the fuel injection strategy in electronically controlled diesel engines to understand the fuel injection mode in modern diesel engines. Moreover, fuel injection mode is a concept covering the injection time and characteristics of fuel injection speed distribution. Fuel injection mode directly affects spray structure, mixing process. as well as physicochemical conditions in the combustion chamber. Therefore, the injectionregime is one of the keys to improving thermal efficiency and minimizing emissions for diesel engines. The injection regime depends on the injection strategies utilized in each type of diesel engine. With many advantages, the electronic fuel injection system has been developed, allowing the development of various injection strategies (pre-injection, main injection, post-injection, and split injection, ... ). In recent years, the optimization of injection regimes and the application of advanced injection strategies have significantly improved combustion efficiency and reduced emissions. This article aims to provide a comprehensive review of various fuel injection techniques utilized in electronically controlled diesel engines - to analyze the advantages and disadvantages of current injection strategies and to suggest research gaps to be-filed.