Section 1 Doppler Anemonmetry
Comparison of Injector Sprays for Gasoline Direct-injection Engines
J Allen, J Heath, G Pitcher, G K Hargrave, and G Wigley
The spray characteristics of a variety of injectors designed for use in gasoline direct injection engines have been measured using phase Doppler anemometry and high-speed digital imaging techniques in atmospheric and elevated pressure regimes. The interpretation of these results and their application to the design of a direct-injected spark-ignition engine are considered.
Spark ignition gasoline engines equipped with direct injection have already reached the market place, installed in mass produced passenger cars (1). This technology has the potential to deliver fuel economy and emissions benefits. Direct injection fuel systems are evolving along three paths.
- Single fluid – high fuel supply pressure injection.
- Dual fluid – low fuel pressure with air-assisted injection.
- Single fluid – low fuel supply pressure with solenoid assisted injection
As part of Lotus' gasoline direct injection research programme, examples of each of these three types of injectors were assessed using a range of complimentary optical diagnostic techniques. The results from this spray characterization have allowed comparison of the relative merits of these injectors and provided direction for suitable combustion chamber designs and fuelling strategies for each type tested.
1.2 Spray measurement techniques
In conjunction with the ...