Most small engine manufacturers are looking to introduce fuel control technology to reduce engine out emissions, however most available conventional fuel injectors consume high levels of power to achieve controlled injection and suitable atomisation of the fuel. Typical fuel injection pressures of 300kPa are required to achieve pulsed injection and up to 10MPa to achieve full atomisation. The addition of an extra air delivery system at pressures of 600kPa can also be employed to atomise the fuel. These methods require many 100's of Watt's of power making them unsuitable for the vast majority of small engine applications.
This paper presents experimental data from a novel electrostatic atomiser designed specifically for application to small engines, with very low power requirements and excellent fuel atomisation.
The process of electrostatic atomisation introduces a controlled electrical charge directly into the fuel and uses this charge to overcome surface tension forces to achieve fuel atomisation with very lower power requirements, typical electrical power consumption figures of ⪡1W and very low fuel delivery pressures are all that is required to achieve atomisation levels of <30μmSMD.
Unlike most conventional electrostatic atomisers [2, 3] which use a single point high voltage electrode aligned concentrically with a single orifice, the novel design presented in this paper uses a planar facetted electrode that is situated above an array of orifices to produce a multi-hole injector which is not limited in its flow rate, but still achieves excellent atomisation.