scholarly journals Evaluation of Exhaust Gas Recirculation and Fuel Injection Strategies for Emission Performance in Marine Two-Stroke Engine

2019 ◽  
Vol 158 ◽  
pp. 4523-4528 ◽  
Author(s):  
Enxing Zhang ◽  
Xingyu Liang ◽  
Fei Zhang ◽  
Peijian Yang ◽  
Xinyi Cao ◽  
...  
Author(s):  
Fengjun Yan ◽  
Junmin Wang

Fueling control in Diesel engines is not only of significance to the combustion process in one particular cycle, but also influences the subsequent dynamics of air-path loop and combustion events, particularly when exhaust gas recirculation (EGR) is employed. To better reveal such inherently interactive relations, this paper presents a physics-based, control-oriented model describing the dynamics of the intake conditions with fuel injection profile being its input for Diesel engines equipped with EGR and turbocharging systems. The effectiveness of this model is validated by comparing the predictive results with those produced by a high-fidelity 1-D computational GT-Power engine model.


2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Mingzhang Pan ◽  
Haiqiao Wei ◽  
Dengquan Feng

Exhaust gas recirculation (EGR) has gained prominence as a significant method to control port fuel injection engine knock caused by high compression ratio and high intake pressure (IP). In this paper, the effect of EGR on knock intensity was investigated under various conditions which included different compression ratios (9:1, 10:1, 11:1), IPs (1.0 bar, 1.2 bar, 1.4 bar) and intake temperatures (ITs, 20 °C, 40 °C, 60 °C). The torque output being a crucial variant was also considered. The results showed that EGR effectively reduced the maximum amplitude of pressure oscillations (MAPO) and knock intensity factor (KI20). The effect of EGR on knock resistance was more significant at higher compression ratio, IP, and IT. The output torque of the engine reached a peak value with a suitable EGR ratio which also controlled the intensity of knock under different conditions.


2009 ◽  
Vol 138 (3) ◽  
pp. 28-36
Author(s):  
Sathaporn CHUEPENG ◽  
Hongming XU ◽  
Athanasios TSOLAKIS ◽  
Mirosław WYSZYŃSKI ◽  
Jonathan HARLAND

The paper presents characterisations of nanoparticle number in exhaust gases from biodiesel blends (B30, 30% of RME by volume with ultra low sulphur diesel fuel, ULSD) combustion in a V6 diesel engine equipped with a common rail fuel injection system. The engine was operated on three steady-state test points extracted from the New European Driving Cycle without engine hardware or the engine management system (EMS) modification. A fast differential mobility spectrometer was used to determine particle number size distribution based on electrical mobility equivalent diameter. The distribution was dependent on the engine operating condition and the rate of exhaust gas recirculation (EGR). The particle size in the nucleation mode from B30 combustion with and without EGR is smaller than that of ULSD while giving higher number concentration for all engine operating conditions tested. However, in the accumulation mode with and without EGR, the smaller sizes and the lower total numbers from B30 combustion were observed. For both fuels, EGR shows insignificant changes to the primary particle size but noticeable increase in particle size and number in the accumulation mode. In overall, compared to the ULSD case, the B30 combustion reduced particle size and lowered total particle number in exhaust gas emitted from the engine with EGR.


Low-temperature combustion(LTC) with multiple injection strategies is a recent trend for NOx and soot reduction in single-cylinder diesel engines. This paper presents a technical study of past research carried out on multiple injections, which are pilot I and pilot II injection before main injection, to decrease engine soot to meet emission legislation while upholding efficiency and decrease or eliminate exhaust after treatment. Previous research indicates that extending ignition lag to enhance the proper premixing, and controlling temperature of combustion to optimal level using Exhaust Gas Recirculation, have been accepted as an important aspect to attain low temperature combustion. In this paper, we first discuss the effect pilot I injection and pilot II injection strategy through varied injection quantity and time range. Thereafter, we briefly review how pilot II injection provides better results compared with the pilot I injection, which is by reason of better premixing, improves the turbulent effect and lowers the emission. Next, we provide a broad overview of the collected works on the effect of injection pressure, temperature and rate of exhaust gas recirculation on engine emissions. We conclude by identifying a few dependencies of engine parameters in low-temperature combustion by multiple injections so as to reduce the engine emissions.


2007 ◽  
Vol 8 (4) ◽  
pp. 365-378 ◽  
Author(s):  
H Ogawa ◽  
T Li ◽  
N Miyamoto

Ultra-low NOx and smokeless operation at higher loads up to half of the rated torque is attempted with large rates of cold exhaust gas recirculation (EGR). NOx decreases below 6 ppm (0.05 g/kW h) and soot significantly increases when first decreasing the oxygen concentration to 16 per cent with cold EGR. However, after peaking at 12–14 per cent oxygen, soot then decreases sharply to essentially zero at 9–10 per cent oxygen while maintaining ultra-low NOx, regardless of fuel injection quantity and injection pressure. However, at higher loads, with the oxygen concentration below 9–10 per cent, the air-fuel ratio has to be over-rich to exceed half of the rated torque, and thermal efficiency, CO, and THC deteriorate significantly. As the EGR rate increases, exhaust gas emissions and thermal efficiency vary with the intake oxygen content rather than with the excess air ratio. Longer ignition delays due to either advancing or retarding the injection timing reduced the smoke emissions, but advancing the injection timing has the advantages of maintaining the thermal efficiency and preventing misfiring. A reduction in the compression ratio is effective to reduce the in-cylinder temperature and increase the ignition delay as well as to expand the smokeless combustion range in terms of EGR and i.m.e.p. (indicated mean effective pressure).


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