scholarly journals A Numerical Investigation on De-NOx Technology and Abnormal Combustion Control for a Hydrogen Engine with EGR System

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1178
Author(s):  
Hao Guo ◽  
Song Zhou ◽  
Jiaxuan Zou ◽  
Majed Shreka
Keyword(s):  
Hot Spots ◽  
Three Dimensional ◽  
Pressure Rise ◽  
Nox Emissions ◽  
Combustion Duration ◽  
Rise Rate ◽  
Peak Heat Release Rate ◽  
Combustion Emissions ◽  
Computational Fluid Dynamics Cfd ◽  
Gas Recirculation

The combustion emissions of the hydrogen-fueled engines are very clean, but the problems of abnormal combustion and high NOx emissions limit their applications. Nowadays hydrogen engines use exhaust gas recirculation (EGR) technology to control the intensity of premixed combustion and reduce the NOx emissions. This study aims at improving the abnormal combustion and decreasing the NOx emissions of the hydrogen engine by applying a three-dimensional (3D) computational fluid dynamics (CFD) model of a single-cylinder hydrogen-fueled engine equipped with an EGR system. The results indicated that peak in-cylinder pressure continuously increased with the increase of the ignition advance angle and was closer to the top dead center (TDC). In addition, the mixture was burned violently near the theoretical air–fuel ratio, and the combustion duration was shortened. Moreover, the NOx emissions, the average pressure, and the in-cylinder temperature decreased as the EGR ratio increased. Furthermore, increasing the EGR ratio led to an increase in the combustion duration and a decrease in the peak heat release rate. EGR system could delay the spontaneous combustion reaction of the end-gas and reduce the probability of knocking. The pressure rise rate was controlled and the in-cylinder hot spots were reduced by the EGR system, which could suppress the occurrence of the pre-ignition in the hydrogen engine.

Characterization of Partially Premixed Combustion With Ethanol: EGR Sweeps, Low and Maximum Loads

2010 ◽  
Vol 132 (8) ◽  
Author(s):  
Vittorio Manente ◽  
Bengt Johansson ◽  
Pert Tunestal
Keyword(s):  
High Efficiency ◽  
Pressure Rise ◽  
Premixed Combustion ◽  
Maximum Pressure ◽  
Pressure Rise Rate ◽  
Start Of Injection ◽  
Partially Premixed Combustion ◽  
Rise Rate ◽  
Partially Premixed ◽  
Gas Recirculation

Exhaust gas recirculation (EGR) sweeps were performed on ethanol partially premixed combustion (PPC) to show different emission and efficiency trends as compared with diesel PPC. The sweeps showed that when the EGR rate is increased, the efficiency does not diminish, HC trace is flat, and CO is low even with 45% of EGR. NOx exponentially decreases by increasing EGR while soot levels are nearly zero throughout the sweep. The EGR sweeps underlined that at high EGR levels, the pressure rise rate is a concern. To overcome this problem and keep high efficiency and low emissions, a sweep in the timing of the pilot injection and pilot-main ratio was done at ∼16.5 bars gross IMEP. It was found that with a pilot-main ratio of 50:50, and by placing the pilot at −60 with 42% of EGR, NOx and soot are below EURO VI levels; the indicated efficiency is 47% and the maximum pressure rise rate is below 10 bar/CAD. Low load conditions were examined as well. It was found that by placing the start of injection at −35 top dead center, the efficiency is maximized, on the other hand, when the injection is at −25, the emissions are minimized, and the efficiency is only 1.64% lower than its optimum value. The idle test also showed that a certain amount of EGR is needed in order to minimize the pressure rise rate.

Impacts of multiple pilot diesel injections on the premixed combustion of ethanol fuel

2017 ◽  
Vol 232 (6) ◽  
pp. 738-754 ◽  
Author(s):  
Tongyang Gao ◽  
Shui Yu ◽  
Tie Li ◽  
Ming Zheng
Keyword(s):  
Direct Injection ◽  
Pressure Rise ◽  
Pilot Injection ◽  
Moderate Pressure ◽  
Ethanol Fuel ◽  
Injection Process ◽  
Rise Rate ◽  
Efficient Combustion ◽  
Gas Recirculation ◽  
The Impact

Engine experiments were carried out to study the impact of multiple pilot injections of a diesel fuel on dual-fuel combustion with a premixed ethanol fuel, using compression ignition. Because of the contrasting volatility and the reactivity characteristics of the two fuels, the appropropriate scheduling of pilot diesel injections in a high-pressure direct-injection process is found to be effective for improving the clean and efficient combustion of ethanol which is premixed with air using a low-pressure port injection. The timing and duration of each of the multiple pilot injections were investigated, in conjunction with the use of exhaust gas recirculation and intake air boosting to accommodate the variations in the engine load. For correct fuel and air management, an early pilot injection of fuel acted effectively as the reactivity improver to the background ethanol, whereas a late pilot injection acted deterministically to initiate combustion. The experimental results further revealed a set of pilot injection strategies which resulted in an increased ethanol ratio, thereby reducing the emission reductions while retaining a moderate pressure rise rate during combustion.

Biodiesel/butanol blends as a pure biofuel excluding fossil fuels: Effects on diesel engine combustion, performance, and emission characteristics

2020 ◽  
Vol 234 (13) ◽  
pp. 2988-3000
Author(s):  
Yongcheng Huang ◽  
Yaoting Li ◽  
Kun Luo ◽  
Jiyuan Wang
Keyword(s):  
Diesel Engine ◽  
Diesel Fuel ◽  
Fossil Fuels ◽  
Pressure Rise ◽  
Emission Characteristics ◽  
Performance And Emission ◽  
Combustion Performance ◽  
Combustion Duration ◽  
Rise Rate ◽  
Ignition Characteristics

Although both biodiesel and n-butanol are excellent renewable biofuels, most of the existing research works merely use them as the additives for petroleum diesel. As the main fuel properties of biodiesel and n-butanol are complementary, the biodiesel/ n-butanol blends are promising to be a pure biomass-based substitute for diesel fuel. In this paper, the application of the biodiesel/ n-butanol blends on an agricultural diesel engine was comprehensively investigated, in terms of the combustion, performance, and emission characteristics. First, the biodiesel/ n-butanol blends with 10%, 20%, and 30% n-butanol by weight were prepared and noted as BBu10 (10 wt% n-butanol + 90 wt% biodiesel), BBu20 (20 wt% n-butanol + 80 wt% biodiesel), and BBu30 (30 wt% n-butanol + 70 wt% biodiesel). It was found that adding 30 wt% n-butanol to biodiesel can reduce the viscosity by 39.3% and increase the latent heat of vaporization by 57.3%. Then the engine test results showed that with the addition of n-butanol to biodiesel, the peak values of the cylinder pressure and temperature of the biodiesel/ n-butanol blends were slightly decreased, the peak values of the pressure rise rate and heat release rate of the blends were increased, the fuel ignition was delayed, and the combustion duration was shortened. BBu20 has the approximate ignition characteristics with diesel fuel. Both the brake thermal efficiency and the brake-specific fuel consumption of BBu30 were increased by the average percentages of 2.7% and 14.9%, while NO x, soot, and CO emissions of BBu30 were reduced by the average percentages of 17.6%, 34.1%, and 15.4%, compared to biodiesel. The above variations became more evident as the n-butanol proportion increased.

Experimental Investigation of Combustion Characteristics of a Single Cylinder Diesel Engine at Altitude

2021 ◽  
pp. 1-21
Author(s):  
Zhentao Liu ◽  
Jinlong Liu
Keyword(s):  
Diesel Engine ◽  
Combustion Process ◽  
Pressure Rise ◽  
Combustion Characteristics ◽  
Atmospheric Conditions ◽  
Single Cylinder ◽  
Combustion Duration ◽  
Rise Rate ◽  
Heavy Duty Diesel ◽  
Intake Pressure

Abstract Concern over the change of atmospheric conditions at high altitudes prompted interests in the deteriorated efficiency and emissions from heavy-duty diesel engines. This study utilized a single-cylinder, four stroke, direct injected diesel engine to experimentally investigate the altitude effects on combustion characteristics. High altitude operations were simulated via reducing the intake pressure but maintaining constant engine speed and torque. The results suggested reduced in-cylinder pressure but increased temperature as altitude rose. The combustion analysis indicated a slight longer ignition delay, raising and retarding the pressure rise rate and energy release rate in the premixed combustion process. A smaller excess air ratio contributed to combustion deterioration, reflected from a retarded end of combustion, a longer combustion duration, a reduced thermal efficiency, and an increased level of incomplete combustion. However, the phasing and combustion profile were not significantly impacted, when the altitude was elevated from sea level to 2000m, at least for the engine and conditions investigated in this study. Consequently, it is not necessary to adjust the engine ECU when operated in the U.S., considering that the mean elevations of most states are lower than 2000m.

Influence of Micro-Emulsified Biodiesel on Combustion and Emission Characteristics of a Turbocharged Diesel Engine

2012 ◽  
Vol 608-609 ◽  
pp. 269-274
Author(s):  
Qi Min Wu ◽  
Ping Sun ◽  
De Qing Mei ◽  
Zhen Chen
Keyword(s):  
Diesel Engine ◽  
Combustion Process ◽  
Pressure Rise ◽  
Operating Conditions ◽  
Maximum Pressure ◽  
Emission Characteristics ◽  
Combustion Duration ◽  
Rise Rate ◽  
Di Diesel Engine ◽  
Emulsified Biodiesel

In this paper, two kinds of micro-emulsified biodiesel containing 5.6% and10% water are prepared. The effects of micro-emulsified biodiesel on engine’s power, combustion and emission characteristics are investigated in a DI diesel engine. The results show that under the rated speed and full load operating conditions, the maximum pressure rise rate and peak heat release rate for micro-emulsified biodiesel increase dramatically, while the ignition delay is prolonged and the combustion duration becomes shorter. Compared to base diesel, the HC, CO and smoke emissions from the engine fueled with biodiesel decrease sharply, except for a 9% increased NOx at large loads. However, micro-biodiesel could significantly reduce the NOx and smoke emissions, except for the higher HC and CO emissions at low and medium loads. When fuelled with 10%MB, the NOx and smoke emissions are 9% and 90% lower than that of diesel, respectively. Results reported here suggest that the application of micro-emulsified biodiesel in diesel engines has a potential to improve combustion process and reduce NOx, PM emissions simultaneously.

scholarly journals Combustion and Emissions of Gasoline Compression Ignition Engine Fuelled with Gasoline-Biodiesel Blends

2021 ◽  
Author(s):  
Yanuandri Putrasari ◽  
Ocktaeck Lim
Keyword(s):  
Combustion Engine ◽  
Direct Injection ◽  
Pressure Rise ◽  
Maximum Pressure ◽  
Compression Ignition ◽  
Biodiesel Blends ◽  
Fuel Blends ◽  
Rise Rate ◽  
Gas Recirculation ◽  
Injection Strategies

A gasoline compression ignition (GCI) engine was proposed to be the next generation internal combustion engine for gasoline. The effect of exhaust gas recirculation (EGR) and intake boosting on combustion and emissions of GCI engine fueled with gasoline-biodiesel blends by partially premixed compression ignition (PPCI) combustions are investigated in this study. Tests were conducted on a single-cylinder direct-injection CI engine, with 5% by volume proportion of biodiesel in gasoline fuel blends. Engine control parameters (EGR rate, intake boosting rate, and various injection strategies) were adjusted to investigate their influences on combustion and emissions of this GCI engine. It is found that changes in EGR rate, intake boosting pressure and injection strategies affect on ignition delay, maximum pressure rise rate and thermal efficiency which is closely tied to HC, CO, NOx and smoke emissions, respectively.

Experimental Research of HCCI Combustion Based on Late Exhaust Duct EGR Strategy

2015 ◽  
Vol 713-715 ◽  
pp. 327-330
Author(s):  
Yin Han Gao ◽  
Yu Chao Jiang ◽  
Peng Cheng ◽  
Jun Cheng Chi ◽  
You Kun Wang
Keyword(s):  
Pressure Rise ◽  
Valve Train ◽  
Maximum Pressure ◽  
Hcci Combustion ◽  
Combustion Duration ◽  
Rise Rate ◽  
Exhaust Duct ◽  
Variable Valve Train ◽  
Test Engine ◽  
Variable Valve

Late exhaust duct EGR strategy is one of internal EGR strategies to realize HCCI combustion. Based on a single-cylinder test engine system equipped with an electronic controlled hydraulic variable valve train system, the effects of valve phases in this strategy were studied. The results show that at engine speed 1000r/min, equivalent air-fuel ratio λ= 1, when the IVO phase is put off, EGR ratio increases gradually, CA10 and CA50 are postponed and combustion duration becomes longer. At the same time, peak pressure and maximum pressure rise rate have a tendency to descend. When the SEVO phase is postponed, the parameters of the test engine will also be affected. However, when the phase is postponed above the critical point, the parameters have a backward trend. The property of HCCI combustion is not sensitive to SEVO phase.

scholarly journals Computational Methodology for Knocking Combustion Analysis in Compression-Ignited Advanced Concepts

2018 ◽  
Vol 8 (10) ◽  
pp. 1707 ◽  
Author(s):  
José Serrano ◽  
Ricardo Novella ◽  
Josep Gomez-Soriano ◽  
Pablo Martinez-Hernandiz
Keyword(s):  
Cfd Simulation ◽  
Initial Conditions ◽  
Three Dimensional ◽  
Pressure Rise ◽  
Navier Stokes ◽  
Maximum Pressure ◽  
Engine Operation ◽  
Partially Premixed Combustion ◽  
Rise Rate ◽  
Operation Results

In the present work, a numerical methodology based on three-dimensional (3D) computational fluid dynamics (CFD) was developed to predict knock in a 2-Stroke engine operating with gasoline Partially Premixed Combustion (PPC) concept. Single-cycle Unsteady Reynolds-Averaged Navier Stokes (URANS) simulations using the renormalization group (RNG) k − ε model were performed in parallel while the initial conditions are accordingly perturbed in order to imitate the variability in the in-cylinder conditions due to engine operation. Results showed a good agreement between experiment and CFD simulation with respect to cycle-averaged and deviation of the ignition timing, combustion phasing, peak pressure magnitude and location. Moreover, the numerical method was also demonstrated to be capable of predicting knock features, such as maximum pressure rise rate and knock intensity, with good accuracy. Finally, the CFD solution allowed to give more insight about in-cylinder processes that lead to the knocking combustion and its subsequent effects.

scholarly journals Effects of Ignition Timing on Combustion Characteristics of a Gasoline Direct Injection Engine with Added Compressed Natural Gas under Partial Load Conditions

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 755
Author(s):  
Peng Zhang ◽  
Jimin Ni ◽  
Xiuyong Shi ◽  
Sheng Yin ◽  
Dezheng Zhang
Keyword(s):  
Natural Gas ◽  
Direct Injection ◽  
Pressure Rise ◽  
Combustion Characteristics ◽  
Gasoline Direct Injection ◽  
Dual Fuel ◽  
Ignition Timing ◽  
Combustion Duration ◽  
Rise Rate ◽  
Dual Fuel Combustion

The gasoline/natural gas dual-fuel combustion mode has been found to have unique advantages in combustion. The ignition timing has a significant impact on the combustion characteristics of gasoline engines. Thus, here we study the combustion characteristics of gasoline/natural gas dual-fuel combustion mode to determine the details of their respective advantages under cooperative combustion. A direct-injection turbocharged gasoline engine was modified, and an engine experimental platform was built for the coordinated control of gasoline direct-injection and natural gas port injection. A low-speed and low-load operating point was selected, and the in-cylinder pressure, heat release rate, pressure rise rate, combustion temperature, ignition delay, and combustion duration under the coordinated combustion of gasoline and natural gas dual fuel at the ignition moment were studied through bench tests among other typical combustion parameters. The results show that with the increase of the ignition advance angle, the maximum cylinder pressure, heat release rate, pressure rise rate, and maximum combustion temperature increase. The ignition advance angle is 28°CA-BTDC, and PES40 has the best fuel synergy effect and the best power performance improvement. The effect of the advance of the ignition advance angle on the ignition delay and the combustion duration reaches the peak at 20°CA-BTDC–22°CA-BTDC, and the improvement of the two periods is more significant at PES60.

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