Sensitivity of a DI Diesel NOx Model to Changes in Common Rail Pressure, Injection Patterns and EGR

Author(s):  
Clíodhna M. Lyons ◽  
David J. Timoney
Author(s):  
Junfeng Zhao ◽  
Junmin Wang

This paper investigates the impact of fuel property variations on the common rail pressure fluctuation in high-pressure common rail (HPCR) system and explores the possibility of identifying the fuel types based on the measurement of rail pressure for internal combustion engines. Fluid transients, particularly the water hammer effect in a HPCR system, are discussed and the 1D governing equations are given. A typical HPCR system model is developed in GT-Suite with the injectors, three-plunger high-pressure pump, and pressure control valve being modeled in a relatively high level of detail. Four different fuels including gasoline, ethanol, diesel, and biodiesel are modeled and their properties including density, bulk modulus, and acoustic wave speed are validated against data in the literature. Simulation results are obtained under different conditions with variable rail pressures and engine speeds. To reduce the excessive rail pressure oscillation caused by multiple injections, only four main-injections are enabled in each engine revolution. The results show that the natural frequency of a common rail varies with the type of fuel filled in it. By applying the fast Fourier transform (FFT) to the pressure signal, the differences of fuel properties can be revealed in the frequency domain. The experiment validation is conducted on a medium-duty diesel engine, which is equipped with a typical HPCR system and piezo-electric injectors. Tests results are given for both pure No. 2 diesel and pure soybean biodiesel at different rail pressure levels and different engine speeds. This approach is proved to be potentially useful for fuel property identification of gasoline-ethanol or diesel-biodiesel blends on internal combustion engines.


2011 ◽  
Vol 347-353 ◽  
pp. 770-773 ◽  
Author(s):  
Zhan Cheng Wang ◽  
Hui Yong Du ◽  
Jian Xin Liu ◽  
Liang Han ◽  
Song Liu

In the middle and small scale diesel engine, the interaction between the spray wall-impingement and air motion plays a fundamental role on the mixture formation process, it also greatly influences the combustion process and the exhaust emissions. An experimental setup for spray impingement visualization has been made in this paper, the influences of common rail pressure and variable inclination angles on spray impingement are investigated. The experimental results show that the splashing volume increases according to the increasing common rail pressure, and the better atomization is achieved. As for variable inclination angle of spray, the upstream of impingement spray decreases and the downstream increases with the increase of inclination of the wall, the change of entrainment is hardly detected, but the overall splashing volume increases slightly.


2005 ◽  
Vol 122 (3) ◽  
pp. 22-31
Author(s):  
Roberto IMARISIO ◽  
Paolo GIARDINA-PAPA ◽  
Massimo SIRACUSA

After the start of mass production in April 2003 of a completely new Euro 4, 1.3 L, common rail Diesel engine, an upgraded variant has been recently developed, with power output increased from 70 to 90 PS and torque output increased from 180 to 200 N·m. To meet this target the combustion system has been deeply revised and common rail pressure increased from 1400 to 1600 bar, while maintaining the multiple injection feature already introduced on the 70 PS variant. Moreover, a variable geometry, small turbocharger has been specifically developed and the mechanical components upgraded to comply with an increased peak cylinder pressure from 140 to 160 bar. In order to comply with Euro 4 emission standards on critical applications with high load factors new control functions have been developed, in order to reduce the dispersion and the drift in durability, such as the lambda control based on an O2 sensor. In spite of Euro 4 emission compliance on most of the forecasted applications with conventional DOC after-treatment, a DPF version will be provided as well, adopting the maintenance free technology already applied on other engines with higher displacement. The 1.3 L SDE family is manufactured in Poland, in a plant located in Bielsko Biala, with an installed production capacity close to 700.000 engines per year.


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