Comparative Study on the Macroscopic Characteristics of Gasoline and Ethanol Spray from a GDI Injector under Injection Pressures of 10 and 60 MPa

Abstract

To reduce particulate matter (PM) emissions from vehicles powered by gasoline direct injection (GDI) engines, increasing the fuel injection pressure has been one promising approach. However, a comparison of macroscopic characteristics between gasoline and ethanol from a GDI injector under an ultrahigh injection pressure of more than 50 MPa has not been reported. The experimental study presented in this paper can provide some new and valuable information about comparing and analyzing the macroscopic characteristics of gasoline and ethanol spray from a GDI injector in both front and side views under injection pressures of 10 and 60 MPa. The experimental results show that compared to ethanol, gasoline spray has a slight advantage in L S (penetration of whole spray), L C (penetration of core region of spray), θ S (spray cone angle), and R I (irregularity of spray boundary) under both P I (injection pressure) = 10 MPa and P I = 60 MPa, which would promote a more homogeneous mixture of air and fuel. Furthermore, the advantage of gasoline in θ S is more pronounced under P I = 60 MPa. At the end of injection, S S (area of whole spray) of gasoline is around 2% larger than ethanol, while its advantage in S C (area of core region of spray) can be around 5%. With the increase of P I from 10 to 60 MPa, a marked increase of R S (the ratio of S C to S S ) and R I indicates that atomization and air−fuel mixture homogeneity can be significantly improved for both gasoline and ethanol spray. Besides, a minor revision to the Dent model helps achieve a significant improvement in the prediction accuracy of L S for both gasoline and ethanol spray under injection pressures of 10 and 60 MPa.

Shadowgraph Tomography of a High Pressure GDI Spray

“…(Jenny et al 2012;Banerjee and Rutland 2015;Linne 2013;Bravo and Kweon 2014;Berni et al 2022). This region is characterized by strong droplet-gas fluid dynamic interactions, which promote air/fuel mixing and the onset and growth of turbulent structures in the gas phase (Mitroglou et al 2007;Ghasemi et al 2014;Lee and Park 2014;Li et al 2022). This would translate into the observed trend of the extinction coefficient.…”

“…Recent decades have seen the development and growing diffusion of gasoline direct injection (GDI) engines, by reason of improved fuel efficiency, power output, and reduced emissions (Zhao 2010;Van Basshuysen and Spicher 2009;Kalwar and Agarwal 2020;Duronio et al 2020). Their development and advancement, as with diesel, have relied significantly on the optimization of the fuel injection process (Hoffmann et al 2014;Pauer et al 2017;Hassdenteufel et al 2022;Li et al 2022;Lee et al 2020), driven by a strong synergy between experimental and numerical investigations (Drake and Haworth 2007;Shost et al 2014;Postrioti et al 2018;Shahangian et al 2020;Arienti et al 2021;Lien et al 2024), in which optical diagnostics played a fundamental role and still does (Drake and Haworth 2007;Hargrave et al 2000;Zhao 2012;Fansler and Parrish 2014;Linne 2013;Berrocal et al 2022). In this context, the usual high-speed imaging techniques for the characterization of the macroscopic parameters of sprays, based on line-of-sight optical extinction techniques, are increasingly applied in computed tomography investigations (Parrish et al 2010; Kristensson et al 2012;Weiss et al 2020;Hwang et al 2020;Lehnert et al2022;Hwang et al 2024;Oh et al 2022;Karathanassis et al 2021).…”

Investigation of a GDI injector with an innovative flowmeter for high-pressure transient flows

“…11 The currently available Coriolis flowmeters can be applied for the measurement of a flowrate characterized by a pressure of up to around 400 bar, 12 although modern diesel injection systems can reach pressure levels of up to 3000 bar, 13 while the 500 bar level is the target for next-generation GDI systems. 14 However, the invasiveness of this family of devices may represent a limit to their application. 15 In this context, a flowrate estimation, based on the measurement of instantaneous pressure traces, represents a very attractive opportunity, due to the characteristics of the pressure sensors, in terms of miniaturization and dynamic response.…”

“…The currently available Coriolis flowmeters can be applied for the measurement of a flowrate characterized by a pressure of up to around 400 bar, 12 although modern diesel injection systems can reach pressure levels of up to 3000 bar, 13 while the 500 bar level is the target for next-generation GDI systems. 14 However, the invasiveness of this family of devices may represent a limit to their application. 15…”

Instantaneous flowrate measurements in high-pressure liquid flows

“…Presently existing Coriolis flowmeters can detect flow rates with pressures up to roughly 400 bar [12], however, actual diesel injection systems can achieve pressure levels of up to 3000 bar [13], while the 500 bar target represents the objective of next generation GDI systems [14]. Besides this, the invasiveness of this class of devices may restrict its applicability [15].…”