6. CONCLUDING REMARKS

　

The effects of injection rate shaping on fuel spray and spray combustion were examined using an electronically controlled fuel injection system. From the experiments and calculations on sprays with triangular injection rate shaping, it was pointed out that the rate of injection rate increase affected not only temporal spray evolution but also spatial fuel distribution in sprays. The fast increase in injection rate resulted in a relatively uniform fuel distribution and the slow increase resulted in a higher concentration of fuel around the spray tip, which greatly affected flame development.

From the experiments on spray with periodical fluctuation of injection rate, it was confirmed that the spray dispersion could be controlled by the amplitude of fluctuation. Also the spray with fluctuation was found to have shortened dense liquid core.

　

Figure 10 Effect of amplitude of injection rate fluctuation on maximum spray width (Average injection rate 4 g/s)

　

Figure 11 High speed cross-sectional images of spray under atmospheric condition (Average injection rate of 4 g/s)

　

7. ACKNOWLEDGMENTS

　

The authors would like to thank Mr. M. Shikama for his contribution in the experiments. The piezoelectric actuator and the injection nozzle used in this study were supplied by DENSO Corporation. This study was partially supported by the grant from the Fundamental Research Developing Association for Shipbuilding and Offshore.

　

8. REFERENCES

　

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