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

Author(s):  
Balasakthivel Kamaraj ◽  
Shankar C Subramanian ◽  
Baskaran Rakkiappan

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.

2020 ◽  
pp. 146808742092603
Author(s):  
Wonmo Kang ◽  
Sukang Pyo ◽  
Hongsuk Kim

Diesel particulate filter regeneration using intake and exhaust throttling is technically simple and economically efficient compared to other methods. The purpose of this study is to investigate not only the reasons for the increase in exhaust temperature during intake or exhaust throttling but also their feasibility as a diesel particulate filter regeneration technology. In this study, a non-road diesel engine having a mechanical fuel injection pump was used for experiments. The changes in exhaust temperatures were measured during intake and exhaust throttling for the no-load maximum revolutions per minute engine condition. The experimental results exhibited that both intake and exhaust throttling reduced the intake air mass flow rate and increased piston pumping, which then increased fuel consumption. These effects were the primary reasons for increasing the temperature of exhaust gases. In particular, intake throttling was more effective than exhaust throttling in terms of reducing the intake air mass flow rate. However, exhaust throttling caused larger pumping losses, resulting in higher fuel consumption. Furthermore, in case of exhaust throttling, engine combustion was possible even at high equivalence ratios because of the larger amounts of residual gases in the combustion chamber. In summary, exhaust throttling is more effective for regenerating a diesel particulate filter at a high temperature than intake throttling. In addition, this study verified the feasibility of diesel particulate filter regeneration using exhaust throttling through analyses of diesel particulate filter regeneration efficiency, fuel consumption, and exhaust concentration when regenerating the diesel particulate filter by increasing the exhaust temperature through exhaust throttling.


Author(s):  
L. F. Martyn ◽  
T. M. B. Silcock

The torsional vibrations which occur on the fuel injection pump of an automotive diesel engine were investigated. Calculations and tests showed that as well as vibrations transmitted from the crankshaft, the fuel pump could vibrate at the natural frequency of the torsional system consisting of the pump and the drive coupling against an infinite mass. This was excited by harmonic torques produced by the pump. Calculations were made to show the effect of variables on the natural frequency of the pump system including the instance when a crankshaft natural frequency coincided with a pump natural frequency. Calculations were also made of the effect of the engine harmonic torques on the pump vibrations. The results were verified by experiments.


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