Analysis of the Combustion Process in a EURO III Heavy-Duty Direct Injection Diesel Engine

2002 ◽  
Vol 124 (3) ◽  
pp. 636-644 ◽  
Author(s):  
J. M. Desantes ◽  
J. V. Pastor ◽  
J. Arre`gle ◽  
S. A. Molina

To fulfill the commitments of future pollutant regulations, current development of direct injection (DI) Diesel engines requires to improve knowledge on the injection/combustion process and the effect of the injection parameters and engine operation conditions upon the spray and flame characteristics and how they affect engine performance and pollutant emissions. In order to improve comprehension of the phenomena inherent to Diesel combustion, a deep experimental study has been performed in a single-cylinder engine with the main characteristics of a six-cylinder engine passing the EURO III legislation. Some representative points of the 13-mode engine test cycle have been considered modifying the nominal values of injection pressure, injection load, intake pressure, engine speed, and injection timing. The study combines performance and emissions experimental measurements together with heat release law (HRL) analysis and high-speed visualization. Controlling parameters for BSFC, NOx, and soot emissions are identified in the last part of the paper.

Author(s):  
Srinath Pai ◽  
Abdul Sharief ◽  
Shiva Kumar

A single cylinder diesel engine upgraded to operate Common Rail Direct Injection (CRDI) system and employed in this investigation. Tests were conducted on this engine using High-Speed diesel (HSD) and Simarouba biodiesel (SOME) blends to determine the influence of Injection Pressure (IP) and Injection Timing (IT) on the performance and emissions. Four unique IP of 400 bar to 1000 bar, in steps of 200 bar and four differing ITs of 10°, 13°, 15° and 18° before Top Dead Center (bTDC) combinations were attempted for the 25% to full load. Compression Ratio (CR) of 16.5 and Engine speed of 1500 RPM was kept constant during all trails. Critical performance parameter like Brake Thermal Efficiency (BTE) and Brake Specific Fuel Consumption (BSFC) were analyzed, primary emission parameters of the diesel engine The NOx and Smoke opacity were recorded. Finally, the outcomes of each combination were discussed.


Author(s):  
Raouf Mobasheri ◽  
Zhijun Peng

High-Speed Direct Injection (HSDI) diesel engines are increasingly used in automotive applications due to superior fuel economy. An advanced CFD simulation has been carried out to analyze the effect of injection timing on combustion process and emission characteristics in a four valves 2.0L Ford diesel engine. The calculation was performed from intake valve closing (IVC) to exhaust valve opening (EVO) at constant speed of 1600 rpm. Since the work was concentrated on the spray injection, mixture formation and combustion process, only a 60° sector mesh was employed for the calculations. For combustion modeling, an improved version of the Coherent Flame Model (ECFM-3Z) has been applied accompanied with advanced models for emission modeling. The results of simulation were compared against experimental data. Good agreement of calculated and measured in-cylinder pressure trace and pollutant formation trends were observed for all investigated operating points. In addition, the results showed that the current CFD model can be applied as a beneficial tool for analyzing the parameters of the diesel combustion under HSDI operating condition.


2013 ◽  
Vol 465-466 ◽  
pp. 448-452
Author(s):  
Mas Fawzi ◽  
Bukhari Manshoor ◽  
Yoshiyuki Kidoguchi ◽  
Yuzuru Nada

Previous work shows that gas-jet ignition with two-stage injection technique is effective to extend lean combustible ranges of CNG engines. In this report, the robustness of the gas-jet ignition with two-stage injection method was investigated purposely to improve the performance of a lean burn direct injection CNG engine. The experiment was conducted using an engine at speed of 900 rpm, fuel-injection-pressure of 3MPa, equivalence ratio at 0.8, and ignition timing at top dead center. The effect of first injection timing on the test engine performance and exhaust emission was analyzed. First injection timings near the gas-jet ignition produced unstable combustion with occurrence of misfires except at a timing which produced distinctively good combustion with low HC and CO emissions. Computational fluid dynamics was used to provide hindsight of the fuel-air mixture distribution that might be the cause of misfires occurrence at certain injection timings.


Author(s):  
Lurun Zhong ◽  
Naeim A. Henein ◽  
Walter Bryzik

Advance high speed direct injection diesel engines apply high injection pressures, exhaust gas recirculation (EGR), injection timing and swirl ratios to control the combustion process in order to meet the strict emission standards. All these parameters affect, in different ways, the ignition delay (ID) which has an impact on premixed, mixing controlled and diffusion controlled combustion fractions and the resulting engine-out emissions. In this study, the authors derive a new correlation to predict the ID under the different operating conditions in advanced diesel engines. The model results are validated by experimental data in a single-cylinder, direct injection diesel engine equipped with a common rail injection system at different speeds, loads, EGR ratios and swirl ratios. Also, the model is used to predict the performance of two other diesel engines under cold starting conditions.


1999 ◽  
Vol 123 (1) ◽  
pp. 167-174 ◽  
Author(s):  
P. J. Tennison ◽  
R. Reitz

An investigation of the effect of injection parameters on emissions and performance in an automotive diesel engine was conducted. A high-pressure common-rail injection system was used with a dual-guided valve covered orifice nozzle tip. The engine was a four-valve single cylinder high-speed direct-injection diesel engine with a displacement of approximately 12 liter and simulated turbocharging. The engine experiments were conducted at full load and 1004 and 1757 rev/min, and the effects of injection pressure, multiple injections (single vs pilot with main), and pilot injection timing on emissions and performance were studied. Increasing the injection pressure from 600 to 800 bar reduced the smoke emissions by over 50 percent at retarded injection timings with no penalty in oxides of nitrogen NOx or brake specific fuel consumption (BSFC). Pilot injection cases exhibited slightly higher smoke levels than single injection cases but had similar NOx levels, while the single injection cases exhibited slightly better BSFC. The start-of-injection (SOI) of the pilot was varied while holding the main SOI constant and the effect on emissions was found to be small compared to changes resulting from varying the main injection timing. Interestingly, the point of autoignition of the pilot was found to occur at a nearly constant crank angle regardless of pilot injection timing (for early injection timings) indicating that the ignition delay of the pilot is a chemical delay and not a physical (mixing) one. As the pilot timing was advanced the mixture became overmixed, and an increase of over 50 percent in the unburned hydrocarbon emissions was observed at the most advanced pilot injection timing.


2003 ◽  
Vol 4 (2) ◽  
pp. 61-86 ◽  
Author(s):  
T. D. Fansler ◽  
M. C. Drake ◽  
B Stojkovic ◽  
M. E. Rosalik

A recently developed spark emission spec-troscopy technique has been used to measure the effects of fuel injection timing, spark timing and intake swirl level on the individual-cycle fuel concentration at the spark gap in a wall-guided spark ignited direct injection (SIDI) engine. The fuel-concentration measurements were made simultaneously with measurements of individual-cycle spark discharge energy and cylinder pressure. Endoscopic imaging of the fuel spray and high-speed imaging of combustion (both broadband and spectrally resolved) augment these quantitative data. For optimum engine operation, the fuel-air equivalence ratio at the spark gap just after spark breakdown is rich on average (〈φ〉 ≈1.4–1.5) and varies widely from cycle to cycle (∼25 per cent). The evolution with crank angle of the mean equivalence ratio and its cycle-to-cycle fluctuations are correlated with the cylinder pressure, heat release and imaging data to provide insights into fuel transport and mixture preparation that are important to understanding and optimizing ignition and combustion in SIDI engines. For example, causes of misfires and partial burns have been determined.


Author(s):  
V. Hariram ◽  
S. Seralathan ◽  
M. Rajasekaran ◽  
G. John

The present experimental investigation aims at improving the combustion and performance parameters by varying the injection timing. A 3.5 kW single cylinder stationary CI engine equipped with eddy current dynamometer is used in this investigation. The static injection timing is varied using spill method by an advancement and retirement of 2 CAD with respect to standard injection timing of 23 BTDC. On comparison with the standard injection timing, the brake thermal efficiency, cylinder pressure, rate of heat release, mean gas temperature and rate of pressure rise are found to increase along with a significant decrease in brake specific fuel consumption for an advanced injection timing of 21 BTDC. Negative improvement is observed with respect to retarded injection timing of 25 BTDC. Optimum parameters for enhanced engine performance is found to be 21 BTDC injection timing with a 200 bar injection pressure at rated speed.


Author(s):  
Xiaoye Han ◽  
Kelvin Xie ◽  
Jimi Tjong ◽  
Ming Zheng

Diesel low temperature combustion (LTC) is capable of producing diesel-like efficiency while emitting ultra-low nitrogen oxides (NOx) and soot emissions. Previous work indicates that well-controlled single-shot injection with exhaust gas recirculation (EGR) is an operative way of achieving diesel LTC from low to mid engine loads. However, as the engine load is increased, demanding intake boost and injection pressure are necessary to suppress high soot emissions during the transition to LTC. The use of volatile fuels such as ethanol is deemed capable of promoting the cylinder charge homogeneity, which helps to overcome the high soot challenge and, thus, potentially expand the engine LTC load range. In this work, LTC investigations were carried out on a high compression ratio (18.2:1) engine. Engine tests were first conducted with diesel and LTC operation at 8 bar indicated mean effective pressure (IMEP) was enabled by sophisticated control of the injection pressure, injection timing, intake boost, and EGR application. The engine performance was characterized as the baseline, and the challenges were identified. Further tests were aimed to improve the engine performance against these baseline results. Experiments were, hence, conducted on the same engine with secondary ethanol port fuelling (PF). Single-shot diesel direct injection (DI) was applied close to top dead center (TDC) to ignite the ethanol and control the combustion phasing. The control sensitivity was studied through injection timing sweeps and EGR sweeps. Additional tests were performed to investigate the ethanol-to-diesel ratio effects on the mixture reactivity and the engine emissions. Engine load was also raised to 16.4 bar IMEP while keeping the simultaneously low NOx and soot emissions. Significant improvement of engine control and emissions was achieved by the DI+PF strategy.


Author(s):  
Xiaoye Han ◽  
Tongyang Gao ◽  
Usman Asad ◽  
Kelvin Xie ◽  
Ming Zheng

Diesel low temperature combustion (LTC) is capable of producing diesel-like efficiency while emitting ultra-low nitrogen oxides (NOx) and soot emissions. Previous work indicates that well controlled single-shot injection with exhaust gas recirculation (EGR) is an operative way of achieving diesel LTC from low to mid engine loads. However, as the engine load is increased, demanding intake boost and injection pressure are necessary to suppress high soot emissions during the transition to LTC. The use of volatile fuels such as ethanol are deemed capable of promoting the cylinder charge homogeneity, which helps to overcome the high soot challenge and thus potentially expand the engine LTC load range. In this work, LTC investigations have been carried out on a high compression ratio (18.2:1) engine. The engine was firstly fuelled with diesel, and LTC operation at 8 bar indicated mean effective pressure (IMEP) was enabled by sophisticated control of the injection pressure, injection timing, intake boost and EGR application. The engine performance was characterized as the baseline, and the challenges were identified. Further tests were aimed to improve the engine performance against these baseline results. Experiments were hence conducted on the same engine with secondary ethanol port injection (PI). Single-shot diesel direct injection (DI) was applied close to top dead center (TDC) to ignite the ethanol and control the combustion phasing. The control sensitivity has been studied through injection timing sweeps and EGR sweeps. Additional tests were performed to investigate the ethanol-to-diesel ratio effects on the mixture reactivity and the engine emissions. Engine load was also raised to 10 bar IMEP while keeping the simultaneously low NOx and soot emissions. Significant improvement of engine control and emissions was achieved by the DI+PI strategy.


2019 ◽  
Vol 19 (4) ◽  
pp. 337-357
Author(s):  
Haroun A.K. Shahad ◽  
Emad D. Abood

Hydrogen is a clean fuel for internal combustion engines since it produces only water vapor and nitrogen oxides when it burns. In this research, hydrogen is used as a blending fuel with diesel to reduce pollutants emission and to improve performance. It is inducted in the inlet manifold, of a single cylinder, four stroke, direct injection, water cold diesel engine, type (Kirloskar). Hydrogen blending is done on energy replacement basis. A special electronic unit is designed and fabricated to control hydrogen blending ratio. The maximum achieved ratio is 30% of input energy and beyond that engine operation becomes unsatisfactory when the air temperature is 20 oC and injection timing of -35o CA which represent the first part of this work. Inlet air heating system is built and added in the experimental work. The heating system allows to increase the air temperature up to 100 oC. A heating of air to 60 oC with injection timing of -30o CA and 55% of hydrogen blending is executed in the second part of this study. Tests are done with 17.5 compression ratio and 1500 rpm. The brake specific fuel consumption is reduced by 29% and 46%, the engine thermal efficiency is increased with 16% and 21% for the 1st and 2nd part respectively. The pollutant emissions of carbon oxides, UHC, and smoke opacity are dramatically decreased by 19.5%, 13%, and 45% respectively for the 1st part and 41%, 38% and 65.6% for the 2nd part while NOx emission is increased by 10% and 25% for the 1st and 2nd part respectively.


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