scholarly journals Effects of EGR and Alternative Fuels on Homogeneous Charge Compression Ignition (HCCI) Combustion Mode

2021 ◽  
Vol 16 (2) ◽  
pp. 135-144
Author(s):  
Saliha Mohammed Belkebir ◽  
Benyoucef Khelidj ◽  
Miloud Tahar Abbes
Keyword(s):  
Alternative Fuels ◽  
Ignition Time ◽  
Combustion Process ◽  
Chemical Species ◽  
Pollutant Emissions ◽  
Combustion Mode ◽  
Hcci Combustion ◽  
Hcci Engines ◽  
Homogeneous Reactor ◽  
Gas Recirculation

We present in this article an analysis of the impacts of the exhaust gas recirculation (EGR) and alternative fuels on HCCI combustion mode. The objective is to reduce the pollutant emissions below the levels of established pollution standards. The ANSYS CHEMKIN-Pro software and the combined chemical kinetics mechanism were used to perform simulations for a closed homogeneous reactor under conditions relevant to HCCI engines. The calculation process is based on one single-zone in the combustion chamber. Numerical simulation has proven the ability of the models adopted, which use the essential mechanisms of the fuel combustion process, to reproduce, among other things, the evolution of the formation of chemical species. This study showed that adding hydrogen (H2) to methane (CH4) is an interesting alternative fuel because it reduces ignition time. It was concluded that an increase of EGR rate conducts to a slower combustion process, lower temperatures, and the reduction of nitrogen oxide (NOX) emissions.

Analysis of the HCCI Combustion of a Turbocharged Truck Engine Using a Stochastic Reactor Model

2002 ◽  
Author(s):  
Luca Montorsi ◽  
Fabian Mauss ◽  
Gian Marco Bianchi ◽  
Amit Bhave ◽  
Markus Kraft
Keyword(s):  
Numerical Simulation ◽  
Combustion Process ◽  
Critical Issue ◽  
Chemical Kinetic ◽  
Reactor Model ◽  
Hcci Combustion ◽  
Hcci Engines ◽  
Homogeneous Reactor ◽  
Power Code ◽  
Truck Engine

Homogeneous Charge Compression Ignition (HCCI) engines arouse great interest due to their high thermal efficiency and very low emissions of nitrogen oxides (NOx) and particulates. Critical issue of the HCCI combustion is the control of the engine since the combustion process is mostly dominated by chemical kinetics. Therefore the accurate assessment of the chemical kinetic is fundamental in numerical simulation of this kind of engines. Experimentally it has been demonstrated that even in HCCI engine the charge within the cylinder is not fully homogeneous, but many quantities, such as temperature, density and equivalence ratio, vary along the combustion chamber. These inhomogeneities influence the combustion process and yield the homogeneous reactor model to be not completely adequate to simulate HCCI combustion. This paper focuses on the use of a stochastic rector model in order to account for temperature inhomogeneities in the numerical simulation of the HCCI combustion. Moreover, the chemical kinetic code has been coupled to GT – Power Code, a 1-D fluid – dynamics code, in order to accurately simulate the operation of a turbocharged truck engine.

Analysis of the HCCI Combustion of a Turbocharged Truck Engine Using a Stochastic Reactor Model

2003 ◽  
Author(s):  
Luca Montorsi ◽  
Fabian Mauss ◽  
Gian Marco Bianchi ◽  
Amit Bhave ◽  
Markus Kraft
Keyword(s):  
Numerical Simulation ◽  
Combustion Process ◽  
Critical Issue ◽  
Chemical Kinetic ◽  
Reactor Model ◽  
Hcci Combustion ◽  
Hcci Engines ◽  
Homogeneous Reactor ◽  
Power Code ◽  
Truck Engine

Homogeneous Charge Compression Ignition (HCCI) engines arouse great interest due to their high thermal efficiency and very low emissions of nitrogen oxides (NOx) and particulates. Critical issue of the HCCI combustion is the control of the engine since the combustion process is mostly dominated by chemical kinetics. Therefore the accurate assessment of the chemical kinetic is fundamental in numerical simulation of this kind of engines. Experimentally it has been demonstrated that even in HCCI engine the charge within the cylinder is not fully homogeneous, but many quantities, such as temperature, density and equivalence ratio, vary along the combustion chamber. These inhomogeneities influence the combustion process and yield the homogeneous reactor model to be not completely adequate to simulate HCCI combustion. This paper focuses on the use of a stochastic rector model in order to account for temperature inhomogeneities in the numerical simulation of the HCCI combustion. Moreover, the chemical kinetic code has been coupled to GT - Power Code, a 1-D fluid–dynamics code, in order to accurately simulate the operation of a turbocharged truck engine.

Improvements in Efficiency and Mixture Formation for an Innovative Diesel HCCI Concept

2009 ◽  
Author(s):  
E. Musu ◽  
R. Rossi ◽  
R. Gentili
Keyword(s):  
Combustion Process ◽  
Pressure Rise ◽  
Pollutant Emissions ◽  
Spontaneous Ignition ◽  
Exhaust Gas ◽  
Mixture Formation ◽  
Hcci Combustion ◽  
Gas Recirculation ◽  
Transfer Flow ◽  
Homogeneous Charge

Homogeneous-charge, compression-ignition (HCCI) combustion is triggered by spontaneous ignition in dilute homogeneous mixtures. The combustion rate must be reduced by suitable solutions such as high rates of Exhaust Gas Recirculation (EGR) and/or lean mixtures. HCCI is considered to be a very effective way to reduce engine pollutant emissions, however only a few production engines have been built. HCCI combustion currently cannot be extended to the whole engine operating range, especially to high loads, since the use of EGR displaces air from the cylinder, limiting engine mean effective pressure, thus the engine must be able to operate also in conventional mode. This paper concerns a study of an innovative concept to control HCCI combustion in diesel-fueled engines. The concept consists in forming a pre-compressed homogeneous charge outside the cylinder and in gradually admitting it into the cylinder during the combustion process. In this way, combustion can be controlled by the transfer flow rate, and high pressure rise rates, typical of standard HCCI combustion, can be avoided. This new combustion concept has been called Homogenous Charge Progressive Combustion (HCPC). This paper concerns CFD analysis focused on improving efficiency and reducing pollutant emissions considering a new HCPC engine configuration. Results show an indicated efficiency around 45% and a consistent reduction of soot emission compared to conventional diesel engine.

A Preliminary Study Towards an Innovative Diesel HCCI Combustion

2007 ◽  
Author(s):  
D. Tamagna ◽  
E. Musu ◽  
R. Gentili
Keyword(s):  
Combustion Process ◽  
Pollutant Emissions ◽  
Spontaneous Ignition ◽  
Exhaust Gas ◽  
Compression Ignition ◽  
Pressure Gradients ◽  
Hcci Combustion ◽  
Preliminary Study ◽  
Gas Recirculation ◽  
Innovative Concept

Homogeneous-charge, compression-ignition (HCCI) combustion is triggered by spontaneous ignition in diluted homogeneous mixtures and has a gradual trend thanks to suitable solutions. It is considered a very effective way to reduce engine pollutant emissions, however only experimental prototypes have been based on this concept, except for a few small two-stroke engines. HCCI combustion is feasible with fuels both for S.I. and for C.I. engines, but currently it does not cover the whole engine operating field, thus the engine must be built to operate also as a conventional engine. In order to obtain a gradual combustion and not a simultaneous reaction (as it would be in spontaneously ignited homogeneous mixture), lean mixture is used and appropriate solutions, as Exhaust Gas Recirculation (EGR), are necessary. However, the admission of exhaust gas into the cylinder goes to detriment of engine maximum mean effective pressure. This paper concerns a preliminary study of an innovative concept to control HCCI combustion in Diesel-fuelled engines, apart from exhaust gas presence, the function of which is limited to NOx emission control. The main purpose of the research is the obtaining of Diesel HCCI combustion also with high mean effective pressures rendering the combustion behaviour more controllable as well. The concept consists in forming a pre-compressed homogenous charge outside the cylinder and in gradually admitting it into the cylinder during the combustion process. In this way, combustion can be controlled by the flow rate transfer and high pressure gradients, typical of common HCCI combustion, can be limited as well. A first analysis has been done, considering a cylinder filled with a perfectly stirred mixture of air and diesel fuel through a transfer duct, only to test the validity of the concept, regardless of which effective solution will be adopted. Both Two and Four Stroke operations have been considered to realize the concept. Results in terms of pressure, heat release rate, temperature and emission production have pointed out the validity of the concept. Especially the Two Stroke solution produces more soot than the conventional Diesel, pointing out that the air-fuel mixing is probably not optimized. Regarding NOx emissions, both the proposed solutions give better results than the conventional Diesel engine.

scholarly journals LES study on mixing and combustion in a Direct Injection Spark Ignition engine

2018 ◽  
Vol 73 ◽  
pp. 32
Author(s):  
Nicolas Iafrate ◽  
Anthony Robert ◽  
Jean-Baptiste Michel ◽  
Olivier Colin ◽  
Benedicte Cuenot ◽  
...  
Keyword(s):  
Ignition Time ◽  
Direct Injection ◽  
Combustion Process ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Pollutant Emissions ◽  
Spark Ignition Engines ◽  
Eddy Simulation ◽  
Mixture Preparation ◽  
The Impact

Downsized spark ignition engines coupled with a direct injection strategy are more and more attractive for car manufacturers in order to reduce pollutant emissions and increase efficiency. However, the combustion process may be affected by local heterogeneities caused by the interaction between the spray and turbulence. The aim for car manufacturers of such engine strategy is to create, for mid-to-high speeds and mid-up-high loads, a mixture which is as homogeneous as possible. However, although injection occurs during the intake phase, which favors homogeneous mixing, local heterogeneities of the equivalence ratio are still observed at the ignition time. The analysis of the mixture preparation is difficult to perform experimentally because of limited optical accesses. In this context, numerical simulation, and in particular Large Eddy Simulation (LES) are complementary tools for the understanding and analysis of unsteady phenomena. The paper presents the LES study of the impact of direct injection on the mixture preparation and combustion in a spark ignition engine. Numerical simulations are validated by comparing LES results with experimental data previously obtained at IFPEN. Two main analyses are performed. The first one focuses on the fuel mixing and the second one concerns the effect of the liquid phase on the combustion process. To highlight these phenomena, simulations with and without liquid injection are performed and compared.

scholarly journals Some aspects of cycle variability at the Diesel engine fuelled with animal fats

2019 ◽  
Vol 112 ◽  
pp. 01014
Author(s):  
Adrian Nicolici ◽  
Constantin Pană ◽  
Niculae Negurescu ◽  
Alexandru Cernat ◽  
Cristian Nuţu
Keyword(s):  
Diesel Engine ◽  
Diesel Fuel ◽  
Alternative Fuels ◽  
Combustion Process ◽  
Pollutant Emissions ◽  
Experimental Investigations ◽  
Maximum Pressure ◽  
Content Increase ◽  
Animal Fats ◽  
Viable Solution

The progressive diminution of the oil reserves all over the world highlights the necessity of using alternative fuels derived from durable renewable resource. The use of the alternative fuels represents a viable solution to reduce the pollutant emissions and to replace fossil fuels. Thus, a viable solution is the use of the animal fats in mixture with the diesel fuel at the diesel engines. A D2156 MTN8 diesel engine was firstly fuelled with diesel fuel and then with different blends of diesel fuel-animal fats (5% and 10% animal fats content). In the paper are presented some results of the experimental investigations of engine fuelled with preheated animal fats. The raw animal fats effects on the combustion process and on the pollutant emissions at different engine loads and 1450 rev/min engine speed are showed. The engine cycle variability increases at the animal fats content increase. The cycle variability for maximum pressure, maximum pressure angle and indicated mean effective pressure is analysed. The cycle variability coefficients values don’t exceed the recommended values of the standard diesel engine.

Contribution to study the effect of exhaust gas recirculation EGR on HCCI combustion mode

2017 ◽  
Vol 35 (1) ◽  
pp. 183-190 ◽  
Author(s):  
Slimane Benhorma ◽  
Mokhtar Aouissi ◽  
C. Mansour ◽  
A. Bounif
Keyword(s):  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Combustion Mode ◽  
Hcci Combustion ◽  
Gas Recirculation

scholarly journals Potential of hydrogen addition to natural gas or ammonia as a solution towards low- or zero-carbon fuel for the supply of a small turbocharged SI engine

2021 ◽  
Vol 312 ◽  
pp. 07022
Author(s):  
Alfredo Lanotte ◽  
Vincenzo De Bellis ◽  
Enrica Malfi
Keyword(s):  
Alternative Fuels ◽  
Laminar Flame ◽  
Combustion Engine ◽  
Numerical Study ◽  
Combustion Process ◽  
Pollutant Emissions ◽  
Si Engine ◽  
Hydrogen Addition ◽  
Emission Regulations ◽  
Zero Carbon

Nowadays there is an increasing interest in carbon-free fuels such as ammonia and hydrogen. Those fuels, on one hand, allow to drastically reduce CO2 emissions, helping to comply with the increasingly stringent emission regulations, and, on the other hand, could lead to possible advantages in performances if blended with conventional fuels. In this regard, this work focuses on the 1D numerical study of an internal combustion engine supplied with different fuels: pure gasoline, and blends of methane-hydrogen and ammonia-hydrogen. The analyses are carried out with reference to a downsized turbocharged two-cylinder engine working in an operating point representative of engine operations along WLTC, namely 1800 rpm and 9.4 bar of BMEP. To evaluate the potential of methane-hydrogen and ammonia-hydrogen blends, a parametric study is performed. The varied parameters are air/fuel proportions (from 1 up to 2) and the hydrogen fraction over the total fuel. Hydrogen volume percentages up to 60% are considered both in the case of methane-hydrogen and ammonia-hydrogen blends. Model predictive capabilities are enhanced through a refined treatment of the laminar flame speed and chemistry of the end gas to improve the description of the combustion process and knock phenomenon, respectively. After the model validation under pure gasoline supply, numerical analyses allowed to estimate the benefits and drawbacks of considered alternative fuels in terms of efficiency, carbon monoxide, and pollutant emissions.

Effect of Turbulence and External Exhaust Gas Recirculation on HCCI Combustion Mode and Exhaust Emissions

2009 ◽  
Vol 23 (9) ◽  
pp. 4295-4303 ◽  
Author(s):  
Francisco J. Jiménez-Espadafor ◽  
Miguel Torres Garcia ◽  
José A. Correa Herrero ◽  
José A. Becerra Villanueva
Keyword(s):  
Exhaust Gas Recirculation ◽  
Exhaust Emissions ◽  
Exhaust Gas ◽  
Combustion Mode ◽  
Hcci Combustion ◽  
Gas Recirculation

scholarly journals Assessment of technical and environmental performance of Marine Alternative fuels for Container Ships

2021 ◽  
Author(s):  
Ahmed G. Elkafas ◽  
Mohamed R. Shouman
Keyword(s):  
Alternative Fuels ◽  
Combustion Process ◽  
Efficiency Index ◽  
Diesel Oil ◽  
Air Pollutant ◽  
Pollutant Emissions ◽  
Dual Fuel ◽  
Shipping Industry ◽  
Marine Diesel ◽  
Dual Fuel Engines

Abstract Environmental issues, for example, the expanded air pollutant emissions from ships are progressively affecting the operation of ships. Therefore, International Maritime Organization (IMO) has adopted many goals to decarbonizing the shipping industry by at least 40% by 2030. Marine fuels play a major role in these goals because of the emissions resulting from the combustion process. Therefore, the present research proposes to convert the conventional engine operated by marine diesel oil (MDO) to a dual-fuel engine operated by either natural gas (NG) or methanol. As a case study, A15-class container ship is investigated. The results showed that the dual-fuel engine operated with (98.5% NG and 1.5% MDO) will reduce CO2, SOx, and NOx emissions by 28%, 98% and 85%, respectively when compared with their values for conventional diesel engine. On the other hand, the reduction percentages reach to 7%, 95% and 80% when using a dual-fuel engine operated with (95% Methanol and 5% MDO), respectively. The proposed dual-fuel engines operated by either NG and methanol will improve the ship energy efficiency index by 26% and 7%, respectively.

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