A Novel Transient Drop Sizing Technique for Investigating the Role of Gasoline Injector Sprays in Fuel Mixture Preparation

A novel measurement technique to evaluate the transient nature of the pulsing sprays from gasoline fuel injectors is created by combining and synchronizing established laser diffraction and high-speed imaging measurements. Both laser diffraction measurements and high-speed images are synchronized, enabling a maximum of two thousand measurements per second to be acquired. By combining the time-resolved drop size measurements with the synchronized spray images, the transient nature of the spray characteristics in relation to injector logic signal timing, injection frequency, and measurement location can be revealed. In addition, the drop size and optical concentration (or obscuration) trends of the spray can be correlated. This paper presents experimental results using this technique on a production dual spray port fuel injector spray. The effects of spray interaction with co-flow air and in the presence of complex intake port geometry are also examined in order to reveal the robustness of this technique. With improved knowledge of the spray characteristics provided by this novel technique, fuel injector designers can choose specific attributes of fuel injectors to concentrate efforts for further improvement and to aid the combustion development processes.