To control fuel injection, optimize combustion and reduce emissions for LPG (liquefied petroleum gas) engines, it is necessary and important to understand the characteristics of LPG sprays. The present work investigates the geometry of LPG sprays, including spray tip penetration, spray angle, projected spray area and spray volume, by using schlieren photography and digital image processing techniques. Two types of single nozzle injectors were studied, with the same nozzle diameter, but one with and one without a double-hole flow-split head. A code developed to analyse the results directly from the digitized images is shown to be more accurate and efficient than manual measurement and analysis. Test results show that a higher injection pressure produces a longer spray tip penetration, a larger projected spray area and spray volume, but a smaller spray cone angle. The injector with the double-hole split-head nozzle produces better atomization and shorter tip penetration at medium and late injection times, but longer tip penetration in the early stage.

No abstract

No abstract

SNCR (Selective Non Catalytic Reduction) system is proposed, with 40% methylamine aqueous solution as reducing agent to reduce NOx in diesel exhaust gas. The effect of injection position and volume on the reduction efficiency through the test bench is systematically researched. A three-dimensional model of a full-sized diesel SNCR system generated by CFD software FIRE is used to investigate the reduction efficiency under different temperatures. The simulated results have a good agreement with the test results, and it can be used to optimize SNCR system. The results can indicate the practical application of this technology.