Reduced NOx emissions from internal combustion engines fuelled by natural gas

Fuel ◽  
1991 ◽  
Vol 70 (4) ◽  
pp. 499-502 ◽  
Author(s):  
Timothy Fowler ◽  
David Lander ◽  
Diane Broomhall
Keyword(s):  
Natural Gas ◽  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Nox Emissions ◽  
Combustion Engines

Numerical Modelling of Internal Combustion Engines Fuelled by Hydrogen-Natural Gas Blends

2008 ◽  
Author(s):  
Antonio Mariani ◽  
Biagio Morrone ◽  
Andrea Unich
Keyword(s):  
Natural Gas ◽  
Internal Combustion Engines ◽  
Exhaust Gas Recirculation ◽  
Internal Combustion ◽  
Flame Speed ◽  
Operating Conditions ◽  
Nox Emissions ◽  
Exhaust Gas ◽  
Combustion Engines ◽  
Gas Recirculation

The strict rules that European Community has given for reducing vehicle emissions require new views on the choice of combustion engines and fuels. In fact, the rules will probably introduce in the near future limitations on carbon dioxide (CO2) emissions. Internal combustion engines are responsible for emission of unburned hydrocarbons (HC), nitrogen oxides (NOx) and particulate matter (PM). The aim of the present paper is the study of the effects of hydrogen-natural gas blends (HCNG) on the performance, efficiency and NOx emissions of internal combustion engines (ICE). A numerical engine model has been developed to display how the presence of hydrogen in such mixtures impacts on flame speed and burn rates. The model allows the comparison of different fuels, in terms of engine brake efficiency and pollutant emissions. An important variable for the combustion process is the ignition timing which is set employing Maximum Brake Torque (MBT) spark advance. Engine operating conditions considered in the numerical analysis have been obtained by imposing engine speed and load. Brake power, efficiency and NOx emissions are calculated for the most frequent operating conditions met by automotive engines, i.e. part load and low speed. The effect of natural gas (NG) enrichment by hydrogen on flame speed has been considered. Thus, faster combustion and the reduction of energy content in the air-fuel mixtures due to the lower density of hydrogen are taken into account. Hydrogen enrichment of natural gas improves combustion stability in critical conditions, allowing the use of extremely lean mixtures or high Exhaust Gas Recirculation rates. The results show that by employing an MBT spark advance, the HCNG blends furnish improvements of engine brake efficiency compared with compressed natural gas (CNG), which are more relevant at part loads and for the higher hydrogen content. Anyway, higher NOx emissions are observed due to the increased temperatures into the cylinders. Thus, the analysis also takes into account the Exhaust Gas Recirculation (EGR) dilution technique to reduce the NOx emissions. A large reduction of such pollutant, which has been estimated greater than 50%, can be achieved by using a 10% EGR. Furthermore higher engine efficiency is obtained using EGR due to reduced pumping work, reduced heat loss to the walls because of lower gas temperature and a reduction in the degree of dissociation in the high temperature burned gases.

Availability analysis of hydrogen/natural gas blends combustion in internal combustion engines

Energy ◽  
2008 ◽  
Vol 33 (2) ◽  
pp. 248-255 ◽  
Author(s):  
C.D. Rakopoulos ◽  
M.A. Scott ◽  
D.C. Kyritsis ◽  
E.G. Giakoumis
Keyword(s):  
Natural Gas ◽  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Availability Analysis

The Effect of Parametric Variations on Formaldehyde Emissions From a Large Bore Natural Gas Engine

2002 ◽  
Author(s):  
Daniel B. Olsen ◽  
Bryan D. Willson
Keyword(s):  
Natural Gas ◽  
Environmental Protection Agency ◽  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Air Pollutant ◽  
Formation Mechanisms ◽  
Combustion Engines ◽  
Gas Engine ◽  
Natural Gas Engine ◽  
Hazardous Air Pollutant

Formaldehyde is a hazardous air pollutant (HAP) that is typically emitted from natural gas-fired internal combustion engines as a product of incomplete combustion. The US Environmental Protection Agency (EPA) is currently developing national emission standards to regulate HAP emissions, including formaldehyde, from stationary reciprocating internal combustion engines under Title III of the 1990 Clean Air Act Amendments. This work investigates the effect that variations of engine operating parameters have on formaldehyde emissions from a large bore natural gas engine. The subject engine is a Cooper-Bessemer GMV-4TF two-stroke cycle engine with a 14″ (36 cm) bore and a 14″ (36 cm) stroke. Engine parameter variations investigated include load, boost, ignition timing, inlet air humidity ratio, air manifold temperature, jacket water temperature, prechamber fuel supply pressure, exhaust backpressure, and speed. The data analysis and interpretation is performed with reference to possible formaldehyde formation mechanisms and in-cylinder phenomena.

scholarly journals 1D Simulation and Experimental Analysis on the Effects of the Injection Parameters in Methane–Diesel Dual-Fuel Combustion

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3734
Author(s):  
Javier Monsalve-Serrano ◽  
Giacomo Belgiorno ◽  
Gabriele Di Blasio ◽  
María Guzmán-Mendoza
Keyword(s):  
Natural Gas ◽  
Internal Combustion Engines ◽  
Large Scale ◽  
Internal Combustion ◽  
Fuel Combustion ◽  
Pollutant Emissions ◽  
Dual Fuel ◽  
Combustion Engines ◽  
Low Carbon ◽  
Dual Fuel Combustion

Notwithstanding the policies that move towards electrified powertrains, the transportation sector mainly employs internal combustion engines as the primary propulsion system. In this regard, for medium- to heavy-duty applications, as well as for on- and off-road applications, diesel engines are preferred because of the better efficiency, lower CO2, and greater robustness compared to spark-ignition engines. Due to its use at a large scale, the internal combustion engines as a source of energy depletion and pollutant emissions must further improved. In this sense, the adoption of alternative combustion concepts using cleaner fuels than diesel (e.g., natural gas, ethanol and methanol) presents a viable solution for improving the efficiency and emissions of the future powertrains. Particularly, the methane–diesel dual-fuel concept represents a possible solution for compression ignition engines because the use of the low-carbon methane fuel, a main constituent of natural gas, as primary fuel significantly reduces the CO2 emissions compared to conventional liquid fuels. Nonetheless, other issues concerning higher total hydrocarbon (THC) and CO emissions, mainly at low load conditions, are found. To minimize this issue, this research paper evaluates, through a new and alternative approach, the effects of different engine control parameters, such as rail pressure, pilot quantity, start of injection and premixed ratio in terms of efficiency and emissions, and compared to the conventional diesel combustion mode. Indeed, for a deeper understanding of the results, a 1-Dimensional spray model is used to model the air-fuel mixing phenomenon in response to the variations of the calibration parameters that condition the subsequent dual-fuel combustion evolution. Specific variation settings, in terms of premixed ratio, injection pressure, pilot quantity and combustion phasing are proposed for further efficiency improvements.

A Numerical Investigation of Combustion Chamber Geometry Effects on Natural Gas Direct Injection Properties in a SI Engine With Centrally Mounted Multi-Hole Injector

2012 ◽  
Author(s):  
Bijan Yadollahi ◽  
Masoud Boroomand
Keyword(s):  
Numerical Model ◽  
Natural Gas ◽  
Flow Field ◽  
Combustion Chamber ◽  
Internal Combustion Engines ◽  
Gasoline Engine ◽  
Direct Injection ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Validity Of Results

Due to the vast resources of natural gas (NG), it has emerged as an alternative fuel for SI internal combustion engines in recent years. The need to have better fuel economy and less emission especially that of greenhouse gases has resulted in development of NG fueled engines. Direct injection of natural gas into the cylinder of SI internal combustion engines has shown great potential for improvement of performance and reduction of engine emissions especially CO2 and PM. Direct injection of NG into the cylinder of SI engines is rather new thus the flow field phenomena and suitable configuration of injector and combustion chamber geometry has not been investigated completely. In this study a numerical model has been developed in AVL FIRE software to perform investigation of direct natural gas injection into the cylinder of spark ignition internal combustion engines. In this regard, two main parts have been taken into consideration aiming to convert an MPFI gasoline engine to direct injection NG engine. In the first part of study multidimensional numerical simulation of transient injection process, mixing and flow field have been performed via different validation cases in order to assure the numerical model validity of results. Adaption of such a modeling was found to be a challenging task because of required computational effort and numerical instabilities. In all cases present results were found to have excellent agreement with experimental and numerical results from literature. In the second part, using the moving mesh capability, the validated model has been applied to methane injection into the cylinder of a direct injection engine. Five different piston head shapes have been taken into consideration in investigations. An inwardly opening multi-hole injector has been adapted to all cases. The injector location has been set to be centrally mounted. The effects of combustion chamber geometry have been studied on mixing of air-fuel inside cylinder via quantitative and qualitative representation of results. Based on the results, suitable geometrical configuration for a NG DI engine has been discussed.

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