Improvement of Emissions From Diesel Engines

1988 ◽  
Vol 110 (3) ◽  
pp. 343-348 ◽  
Author(s):  
T. Morimatsu ◽  
T. Okazaki ◽  
T. Furuya ◽  
H. Furukawa
Keyword(s):  
Mass Transfer ◽  
Combustion Chamber ◽  
Diesel Engines ◽  
Fuel Injection ◽  
Injection Pressure ◽  
Air Entrainment ◽  
Injection Timing ◽  
Injection Pump ◽  
High Injection ◽  
High Injection Pressure

It is important to reduce emissions from diesel engines, which are used in the cogeneration systems. The mass transfer to the fuel spray plays various roles in fuel consumption rate and in trace species emission. High injection pressure and a re-entrant combustion chamber were used to make the mass transfer larger. The need for high injection pressure and controlled injection timing for NOx led the authors to use the new Komatsu fuel injection pump. This pump, which has a re-entrant combustion chamber, resulted in clean engine emissions and confirmed the importance of air entrainment to the spray.

Impact of Very High Injection Pressure on Soot Emissions of Medium Speed Large Diesel Engines

2014 ◽  
Author(s):  
Michael Engelmayer ◽  
Gert Taucher ◽  
Andreas Wimmer ◽  
Gernot Hirschl ◽  
Thomas Kammerdiener
Keyword(s):  
Soot Formation ◽  
Injection Pressure ◽  
Injection System ◽  
Nozzle Geometry ◽  
Injection Timing ◽  
High Injection ◽  
High Injection Pressure ◽  
Soot Emissions ◽  
The Impact ◽  
Very High

Measures exist to adjust tailpipe NOx emissions to assigned values, for example cooled exhaust gas recirculation (EGR) or a SCR catalyst in conjunction with urea. The situation is quite different with soot when use of a trap is not feasible for reasons of cost, space requirements and maintenance. Due to the highly complex soot formation and oxidation process, soot emissions can’t be targeted as easily as NOX. So how can soot be kept within the limits? In principle, soot can be controlled by allocating sufficient oxygen and establishing good mixing conditions with vaporized fuel. The most effective measures target the injection system, e.g. increasing injection pressure, applying multiple injections, optimizing nozzle geometry. To investigate the impact of very high injection pressure on soot, an advanced injection system with rail pressure capability up to 3000 bar and a Bosch injector was installed at the Large Engines Competence Center (LEC) in Graz. Full load and part load operating points at constant speed and in accordance with the propeller law were investigated at the test bed to quantify the impact of high injection pressure on soot emissions. Test runs were conducted with both SCR and EGR while varying injection timing and air-fuel ratios. Use of a statistical method, Design of Experiments (DOE), helped reduce the number of tests. Optical investigations of the spray and combustion were conducted. The goal was to obtain soot concentration history traces with the two color method in order to better understand how soot originates and to be able to calibrate 3D CFD FIRE spray models for use with injection pressures of up to 3000 bar. Very low soot emissions can be achieved using high pressure injection, even when EGR is applied. DOE results provide a clear picture of the relationships between the parameters and can be used to optimize set values for the whole speed and load range. A reliable spray break up model can be used in further 3D CFD simulation to investigate how to reduce soot emissions.

scholarly journals Visualization Investigation of the Influence of Chamber Profile and Injection Parameters on Fuel Spray Spreading in a Double-Layer Diverging Combustion Chamber for a DI Diesel Engine

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2343 ◽  
Author(s):  
Yao Fu ◽  
Liyan Feng ◽  
Hua Tian ◽  
Wuqiang Long ◽  
Dongsheng Dong ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Double Layer ◽  
Fuel Injection ◽  
Injection Pressure ◽  
Positive Influence ◽  
Fuel Spray ◽  
Distribution Area ◽  
Injection Timing ◽  
Injection Parameters ◽  
Spray Distribution

The double-layer diverging combustion chamber (DLDC chamber) aims to improve the fuel–air mixing formation and promote in-cylinder air utilization by changing fuel spray spreading characteristics. In order to investigate how the DLDC chamber profile and injection parameters affect the fuel spray spreading, visualization of fuel injection and impingement tests were carried out on two different DLDC chambers with different fuel injection parameters. The visualization test results showed that double-layer fuel spray spreading was obtained in the two DLDC chambers and the peripheral top clearance of each chamber was utilized efficiently. The DLDC chamber with a 50% upper layer volume provided a larger fuel spray distribution region after the start of injection. The DLDC chamber with a 70% upper layer volume obtained a larger fuel spray distribution region with better top clearance utilization at the later stage of injection. The injection parameters mentioned in this research showed significant effects on the fuel spray spreading in the DLDC chamber. Increasing the injection pressure provided a larger fuel spray distribution area at the beginning of injection. Decreasing the nozzle hole diameter had a positive influence on obtaining a larger fuel spray distribution. Advancing the injection timing enabled the enlarging of the fuel distribution region.

A Study on the Performance and Emissions Characteristics of a DI Compression Ignition Engine Operated With LPG and DTBP Blending Fuels

2011 ◽  
Author(s):  
Hoin Kang ◽  
Jerald A. Caton ◽  
Seangwock Lee ◽  
Seokhwan Lee ◽  
Seungmook Oh
Keyword(s):  
Combustion Chamber ◽  
Fuel Injection ◽  
Ambient Pressure ◽  
Injection Pressure ◽  
Chamber Pressure ◽  
Injection Timing ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Bench Tests ◽  
Fuel Injection Pressure

LPG (Liquefied Petroleum Gas) has been widely used as an alternative fuel for gasoline and diesel vehicles in light of clean fuel and diversity of energy resources. But conventional LPG vehicles using carburetors or MPI fuel injection systems can’t satisfy the emissions regulations and CO2 targets of the future. Therefore, it is essential to develop LPG engines of spark ignition or compression ignition type such that LPG fuel is directly injected into the combustion chamber under high pressure. A compression ignition engine using LPG is the ideal engine with many advantages of fuel economy, heat efficiency and low CO2, even though it is difficult to develop due to the unique properties of LPG. This paper reports on numerical and experimental studies related to LPG fuel for a compression ignition engine. The numerical analysis is conducted to study the combustion chamber shape with CATIA and to analyze the spray and fluid behaviors with FLUENT for diesel and LPG (n-butane 100%) fuels. In one experimental study, a constant volume chamber is used to observe the spray formation for the chamber pressure 0 to 3MPa and to analyze the flame process, P-V diagram, heat release rate and emissions through the combustion of LPG fuel with the cetane additive DTBP (Di-tert-butyl peroxide) 5 to 15 wt% at 25MPa of fuel injection pressure. In engine bench tests, experiments were performed to find the optimum injection timing, lambda, COV and emissions for the LPG fuel with the cetane additive DTBP 5 to 15 wt% at 25MPa fuel injection pressure and 1500 rpm. The penetration distance of LPG (n-butane 100%) was shorter than that of diesel fuel and LPG was sensitive to the chamber pressure. The ignition delay was in inverse proportion to the ambient pressure linearly. In the engine bench tests, the optimum injection timing of the test engine to the LPG fuel with DTBP 15 wt% was about BTDC 12° CA at all loads and 1500 rpm. An increasing of DTBP blending ratio caused the promotion of flame and fast burn and this lead to reduce HC and CO emissions, on the other hand, to increase NOx and CO2 emissions.

Deformation of nozzle, needle, and control plunger of solenoid fuel injector under high injection pressure

2018 ◽  
Vol 233 (7) ◽  
pp. 1767-1782 ◽  
Author(s):  
Dong-wei Wu ◽  
Bai-gang Sun ◽  
Dan Xu
Keyword(s):  
High Pressure ◽  
Fuel Injection ◽  
Injection Pressure ◽  
Geometric Parameters ◽  
Structural Deformation ◽  
Fuel Injector ◽  
Longitudinal Deformation ◽  
High Injection ◽  
High Injection Pressure ◽  
And Control

Future diesel engines require the use of solenoid fuel injection system with the ultra-high pressure of more than 2000 bars. The nozzle, needle, and control plunger of the solenoid injector deform under high pressure. This deformation affects the movement characteristics of the needle, thereby influencing the precise control of fuel injection. A test rig is set up to investigate the structural deformation and influencing factors of the solenoid injector under high pressure. The structural deformation of nozzle, needle, and control plunger under different pressures can be obtained by measuring the displacement of the upper end of the control plunger in the axial direction. The experimental longitudinal deformation of nozzle, needle, and control plunger of the solenoid injector, which was selected for the study, reaches 0.109 mm under the pressure of 1600 bars. This value is close to 40% of the maximum needle lift, which is 0.3 mm. Thus, the deformation can no longer be ignored. In view of the solenoid injector deformation under high injection pressure, a three-dimensional calculation model is established. The calculated results are compared with the experimental data. The calculation total longitudinal deformation of nozzle, needle, control plunger, and contact surface reaches 0.238 mm under the pressure of 2500 bars. The structure deformation of solenoid injector with different materials or geometric parameters is calculated under the pressure of 100–2500 bars. The deformation with new materials is 0.198 mm and the deformation with new geometric parameters is 0.0333 mm under the pressure of 2500 bar. These calculations show that the use of shorter control plungers, shorter needles, and larger wall thickness nozzles can effectively reduce injector deformation under high pressure. The results of the study can provide guidance on injector design, which can work with high injection pressure and much accurate injection.

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