Numerical and experimental analysis of fluid–fluid interaction and flow through micro clearance to estimate leakages in a fuel injection pump

Abstract

It has been observed during the operation of the diesel engine fuel injection pump that the fuel and the lubrication oil leak through the working clearance between the piston and the cylinder bore and mix with each other. The leakage of lubrication oil to fuel (OtF) leads to injector nozzle coking and emission, which necessitates the automotive industry to design a robust fuel injection pump to meet stringent emission norms. Similarly, the leakage of fuel to lubrication oil leads to depreciation of lubrication property of the oil, thereby reducing the life of engine oil lubricated components. In this research, the leakage flow through this clearance gap was studied using the numerical simulation tool, Ansys CFX, to estimate the volume flow rate of lubrication oil to fuel and fuel to lubrication oil. Pressure and drag effects are two important mechanisms that drive the leakage process. The simulation was carried out for various design parameters such as clearance, clearance taper and speed, and experiments were performed to determine the lubrication oil to fuel and fuel to lubrication oil flow rates. The diluted samples collected from fuel and lubrication oil tanks were analyzed using ICP-AES (inductively coupled plasma – atomic emission spectrometry) for calcium and barium element tracing. Calibration was performed on the ICP bench to study the accuracy and repeatability of the test sample analysis method. The results of numerical simulations and experiments were compared for various design parameters. The proposed analysis could serve as a valuable aid in the fuel injection pump development process.

Keywords

Fuel injection pump fuel leakage lubrication oil leakage fuel and lubrication oil mixing leakage simulation experimental leakage flow flow through clearances

Get full access to this article

View all access options for this article.

References

Barker J, Richard P, Snape C and Meredith W. Diesel Injector Deposits – An Issue That Has Evolved with Engine Technology. SAE Technical Paper 2011-01-1923 2011. doi: 10.4271/2011-01-1923.

Sandro

Martin

Koni

. Contribution of unburned lubricating oil and diesel fuel to particulate emission from passenger cars. Atmos Environ 2005; 39: 6985–6994.

Bergada

Kumar

Davies

. A complete analysis of axial piston pump leakage and output flow ripples. Appl Math Model 2012; 36: 1731–1751.

Yang

. Fluid dynamics of axial piston seal. Indus Lubricat Tribol 2010; 62: 12–15.

Milani

. Designing hydraulic locking balancing grooves. Proc IMechE, Part I: J Systems and Control Engineering 2001; 215: 453–465.

Kumar

Bergada

. The effect of piston grooves performance in an axial piston pumps via CFD analysis. Int J Mech Sci 2013; 66: 168–179.

Kamaraj B, Subramanian SC and Rakkiappan B. Numerical analysis of fluid – fluid interaction and flow through micro clearance to estimate leakages in a fuel injection pump. In: ASME proceedings of the international mechanical engineering congress and exposition, Montreal, Canada, 14–20 November 2014, IMECE2014-37411.

Gaiser

. Measurement of exchange of lubricant and fuel in injection pump. Wear 1971; 17: 227–227.

ANSYS, ANSYS CFX User’s Guide, 2010, Release 13.0.

10.

ASTM D5185-13, Standard Test Method for Multielement Determination of Used and Unused Lubricating Oils and Base Oils by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES), ASTM International, West Conshohocken, PA, 2013, www.astm.org.

11.

ASTM D7111-11, Standard Test Method for Determination of Trace Elements in Middle Distillate Fuels by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES), ASTM International, West Conshohocken, PA, 2011, www.astm.org.