scholarly journals Effects of pilot injection timing and EGR on a modern V6 common rail direct injection diesel engine

Author(s):  
Nik Rosli Abdullah ◽  
Rizalman Mamat ◽  
Miroslaw L Wyszynski ◽  
Anthanasios Tsolakis ◽  
Hongming Xu
2018 ◽  
Vol 234 ◽  
pp. 03007
Author(s):  
Plamen Punov ◽  
Tsvetomir Gechev ◽  
Svetoslav Mihalkov ◽  
Pierre Podevin ◽  
Dalibor Barta

The pilot injection strategy is a widely used approach for reducing the noise of the combustion process in direct injection diesel engines. In the last generation of automotive diesel engines up to several pilot injections could occur to better control the rate of heat release (ROHR) in the cylinder as well as the pollutant formation. However, determination of the timing and duration for each pilot injection needs to be precisely optimised. In this paper an experimental study of the pilot injection strategy was conducted on a direct injection diesel engine. Single and double pilot injection strategy was studied. The engine rated power is 100 kW at 4000 rpm while the rated torque is 320 Nm at 2000 rpm. An engine operating point determined by the rotation speed of 1400 rpm and torque of 100 Nm was chosen. The pilot and pre-injection timing was widely varied in order to study the influence on the combustion process as well as on the fuel consumption.


Author(s):  
Hyun Kyu Suh ◽  
Hyun Gu Rho ◽  
Chang Sik Lee

The aim of this work is to investigate the effect of mixing ratio and pilot injection on spray and combustion characteristics of biodiesel fuel and compared with those of diesel fuel in a direct injection common-rail diesel engine. In order to study the influence factors of biodiesel fuel on the spray and combustion characteristics, the experiments were conducted at various mixing ratios and injection conditions of the biodiesel and engine operating conditions. The macroscopic and microscopic characteristics such as injection rate, split injection effect, spray tip penetration, droplet diameter, and axial velocity distribution of biodiesel fuel were compared with the results of conventional diesel fuel by using spray visualization system composed of Ar-ion laser, ICCD camera and phase Doppler particle analyzer (PDPA) system. The combustion and exhaust emission characteristics of biodiesel fuel were studies using common-rail diesel engine with four cylinders. For the biodiesel blended fuel, it was revealed that higher injection pressure is needed to achieve the same injection rate at the higher mixing ratio. The spray tip penetration of biodiesel fuel was much the same with those of diesel. The atomization characteristics of biodiesel were inferior to conventional diesel fuel due to high viscosity and surface tension. The peak combustion pressures of both fuels were increased with advanced injection timing and the combustion pressure of biodiesel fuel is higher than that of diesel fuel. As the pilot injection timing is advanced to the TDC, the dissimilarities of both fuels combustion pressure are reduced. It can be also founded that the pilot injection can enhance the deteriorated spray and combustion characteristics of biodiesel fuel caused by physical fuel properties.


Author(s):  
Hyun Kyu Suh ◽  
Hyun Gu Roh ◽  
Chang Sik Lee

The aim of this work is to investigate the effect of the blending ratio and pilot injection on the spray and combustion characteristics of biodiesel fuel and compare these factors with those of diesel fuel in a direct injection common-rail diesel engine. In order to study the factors influencing the spray and combustion characteristics of biodiesel fuel, experiments involving exhaust emissions and engine performance were conducted at various biodiesel blending ratios and injection conditions for engine operating conditions. The macroscopic and microscopic spray characteristics of biodiesel fuel, such as injection rate, split injection effect, spray tip penetration, droplet diameter, and axial velocity distribution, were compared with the results from conventional diesel fuel. For biodiesel blended fuel, it was revealed that a higher injection pressure is needed to achieve the same injection rate at a higher blending ratio. The spray tip penetration of biodiesel fuel was similar to that of diesel. The atomization characteristics of biodiesel show that it has higher Sauter mean diameter and lower spray velocity than conventional diesel fuel due to high viscosity and surface tension. The peak combustion pressures of diesel and blending fuel increased with advanced injection timing and the combustion pressure of biodiesel fuel is higher than that of diesel fuel. As the pilot injection timing is retarded to 15deg of BTDC that is closed by the top dead center, the dissimilarities of diesel and blending fuels combustion pressure are reduced. It was found that the pilot injection enhanced the deteriorated spray and combustion characteristics of biodiesel fuel caused by different physical properties of the fuel.


2002 ◽  
Vol 125 (1) ◽  
pp. 351-357 ◽  
Author(s):  
Y. Kidoguchi ◽  
M. Sanda ◽  
K. Miwa

Effects of combustion chamber geometry and initial mixture distribution on the combustion process were investigated in a direct-injection diesel engine. In the engine experiment, a high squish combustion chamber with a squish lip could reduce both NOx and particulate emissions with retarded injection timing. According to the results of CFD computation and phenomenological modeling, the high squish combustion chamber with a central pip is effective to keep the combusting mixture under the squish lip until the end of combustion and the combustion region forms rich and highly turbulent atmosphere. This kind of mixture distribution tends to reduce initial burning, resulting in restraint of NOx emission while keeping low particulate emission.


1987 ◽  
Vol 109 (2) ◽  
pp. 187-192 ◽  
Author(s):  
A. C. Alkidas

The factors influencing premixed burning and the importance of premixed burning on the exhaust emissions from a small high-speed direct-injection diesel engine were investigated. The characteristics of premixed and diffusion burning were examined using a single-zone heat-release analysis. The mass of fuel burned in premixed combustion was found to be linearly related to the product of engine speed and ignition-delay time and to be essentially independent of the total amount of fuel injected. Accordingly, the premixed-burned fraction increased with increasing engine speed, with decreasing fuel-air ratio and with retarding injection timing. The hydrocarbon emissions did not correlate well with the premixed-burned fraction. In contrast, the oxides of nitrogen emissions were found to increase with decreasing premixed-burned fraction, indicating that diffusion burning, and not premixed burning, is the primary source of oxides of nitrogen emissions.


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