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Development and Validation Procedure of a 1D Predictive Model for Simulation of a Common Rail Fuel Injection System Controlled with a Fuel Metering Valve

Journal Article
03-11-04-0027
ISSN: 1946-3936, e-ISSN: 1946-3944
Published July 10, 2018 by SAE International in United States
Development and Validation Procedure of a 1D Predictive Model for
                    Simulation of a Common Rail Fuel Injection System Controlled with a Fuel
                    Metering Valve
Sector:
Citation: Ferrari, A., Pizzo, P., and Vitali, R., "Development and Validation Procedure of a 1D Predictive Model for Simulation of a Common Rail Fuel Injection System Controlled with a Fuel Metering Valve," SAE Int. J. Engines 11(4):401-422, 2018, https://doi.org/10.4271/03-11-04-0027.
Language: English

Abstract:

A fully predictive one-dimensional model of a Common Rail injection apparatus for diesel passenger cars is presented and discussed. The apparatus includes high-pressure pump, high-pressure pipes, injectors, rail and a fuel-metering valve that is used to control the rail pressure level.
A methodology for separately assessing the accuracy of the single submodels of the components is developed and proposed. The complete model of the injection system is finally validated by means of a comparison with experimental high-pressure and injected flow-rate time histories.
The predictive model is applied to examine the fluid dynamics of the injection system during either steady-state or transient operations. The influence of the pump delivered flow-rate on the rail-pressure time history and on the injection performance is analysed for different energizing times and nominal rail pressure values.
A comparison between fuel metering valve and pressure-control-valve strategies is also carried out in terms of rail pressure and pump delivered flow-rate time histories. The advantages and the weak points of each strategy are highlighted: the fuel metering valve control is more efficient, due to the absence of a throttling of high-pressure fuel, but leads to poorer dynamic response during nominal rail pressure transients.
Even though the injection performance is the same under steady-state working conditions, significant differences between the two strategies can occur during engine transients.