Video Imaging and Analysis of Common Rail Sprays in an Optical Engine Using Shadowgraphy Technique 2000-01-1255
Common Rail fuel injection equipment offers to diesel combustion a flexible choice of injection timing, injection pressure and fuel quantity with one or more injection events. This paper explores the spray characteristics for rail pressures of 200 to 1600 bar. A novel technique has been developed to capture shadowgraphs of sprays on video from consecutive injections at pseudo framing rates of 25000 frames/sec.
Pulse laser illuminated shadowgraphy was employed to illuminate and display the diesel sprays in an experimental engine with optical access. Spray images were recorded on video at different time intervals from a number of consecutive injections from the start of injection using an electronic auto incrementing sequencer. The sprays formed by a 5 hole and a single hole VCO nozzle were recorded to quantify the influence of rail pressures and fuelling on spray characteristics.
A number of new techniques have been developed and used to characterize the sprays from Lucas Diesel Common Rail (LDCR) injectors. Results are presented on evolution of sprays with time, spray tip and liquid core penetrations, cyclic variations and cone angles. The spray image results show good shot-to-shot consistency from the LDCR injector used in the study. The new techniques are being used to maximize the benefits from the LDCR system in future HSDI engines.