Paper 1: Critical Factors in the Application of Dual-Fuel Engines

Author(s):  
P. W. A. Eke ◽  
J. H. Walker ◽  
M. A. Williams

A dual-fuel engine may be defined as a compression-ignition engine using mainly gaseous fuel but with a small quantity of fuel oil injected as an ignition source; the engine can be changed over instantaneously and under load to operate on liquid fuel alone. The recent availability of natural gas in this country once again attracts the attention of engineers towards gas as a fuel for internal-combustion engines. This paper traces the development of dual-fuel engines, originally using sewage gas and more recently using natural gas, and considers their advantages, both technical and economic, compared with spark-ignited and diesel engines. The dual-fuel engines within the authors' experience are described. The critical factors in handling natural gas in its liquid form are considered, and the extended scope of dual-fuel engines and alternative fuel engines in mobile applications is briefly reviewed. Finally, the paper examines the future for dual-fuel engines and suggests directions in which further development is required.

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 6127
Author(s):  
Md Arman Arefin ◽  
Md Nurun Nabi ◽  
Md Washim Akram ◽  
Mohammad Towhidul Islam ◽  
Md Wahid Chowdhury

Climate change and severe emission regulations in many countries demand fuel and engine researchers to explore sustainable fuels for internal combustion engines. Natural gas could be a source of sustainable fuels, which can be produced from renewable sources. This article presents a complete overview of the liquefied natural gas (LNG) as a potential fuel for diesel engines. An interesting finding from this review is that engine modification and proper utilization of LNG significantly improve system efficiency and reduce greenhouse gas (GHG) emissions, which is extremely helpful to sustainable development. Moreover, some major recent researches are also analyzed to find out drawbacks, advancement and future research potential of the technology. One of the major challenges of LNG is its higher flammability that causes different fatal hazards and when using in dual-fuel engine causes knock. Though researchers have been successful to find out some ways to overcome some challenges, further research is necessary to reduce the hazards and make the fuel more effective and environment-friendly when using as a fuel for a diesel engine.


Author(s):  
Hongsheng Guo ◽  
Brian Liko ◽  
W. Stuart Neill

As an inexpensive and low carbon fuel, the combustion of natural gas reduces fuel cost and generates less carbon dioxide emissions than diesel and gasoline. Natural gas is also a clean fuel that generates less particulate matter emissions than diesel during combustion. Replacing diesel by natural gas in internal combustion engines is of great interest for industries. Dual fuel combustion is an efficient way to apply natural gas in internal combustion engines. An issue that to a certain extent offsets the advantage of lower carbon dioxide emissions in natural gas–diesel dual fuel engines is the higher methane emissions and low engine efficiency at low load conditions. In order to seek strategies to improve the performance of dual fuel engines at low load conditions, an experimental investigation was conducted to investigate the effect of diesel injection split on combustion and emissions performance of a heavy duty natural gas–diesel dual fuel engine at a low load. The operating conditions, such as engine speed, load, intake temperature and pressure, were well controlled during the experiment. The effects of diesel injection split ratio and timings were investigated. The engine efficiency and emissions data, including particulate matter, nitric oxides, carbon monoxide and methane were measured and analyzed. The results show that diesel injection split significantly reduced the peak pressure rise rate. As a result, diesel injection split enabled the engine to operate at a more optimal condition at which engine efficiency and methane emissions could be significantly improved compared to single diesel injection.


Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3734
Author(s):  
Javier Monsalve-Serrano ◽  
Giacomo Belgiorno ◽  
Gabriele Di Blasio ◽  
María Guzmán-Mendoza

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.


Author(s):  
Hongsheng Guo ◽  
Brian Liko ◽  
Luis Luque ◽  
Jennifer Littlejohns

The combustion of natural gas reduces fuel cost and generates less emissions of carbon dioxide and particulate matter than diesel and gasoline. Replacing diesel by natural gas in internal combustion engines is of great interest for transportation and stationary power generation. Dual fuel combustion is an efficient way to burn natural gas in internal combustion engines. In natural gas–diesel dual fuel engines, unburned hydrocarbon emissions increase with increasing natural gas fraction. Many studies have been conducted to improve the performance of natural gas–diesel dual fuel engines and reported the performance of combustion and emissions of regulated pollutants and total unburned hydrocarbon at various engine operating strategies. However, little has been reported on the emissions of different unburned hydrocarbon components. In this paper, an experimental investigation was conducted to investigate the combustion performance and emissions of various unburned hydrocarbon components, including methane, ethane, ethylene, acetylene, propylene, formaldehyde, acetaldehyde and benzaldehyde, at a low engine load condition. The operating conditions, such as engine speed, load, intake temperature and pressure, were well controlled during the experiment. The combustion and emissions performance of pure diesel and natural gas–diesel dual fuel combustion were compared. The effect of diesel injection timing was analyzed. The results show that appropriately advancing diesel injection timing to form a homogeneous charge compression ignition-like combustion is beneficial to natural gas–diesel dual fuel combustion at low load conditions. The emissions of different unburned hydrocarbon components changed in dual fuel combustion, with emissions of some unburned hydrocarbon components being primarily due to the combustion of natural gas, while those of others being more related to diesel combustion.


Author(s):  
Miroslav P. Petrov ◽  
Thomas Stenhede ◽  
Andrew R. Martin ◽  
Laszlo Hunyadi

Hybrid dual-fuel combined cycle power plants employ two or more different fuels (one of which is typically a solid fuel), utilized by two or more different prime movers with a thermal coupling in between. Major thermodynamic and economic advantages of hybrid combined cycle configurations have been pointed out by various authors in previous studies. The present investigation considers the performance of natural gas and biomass hybrid combined cycles in small scale, with an internal combustion engine as topping cycle and a steam boiler/turbine as bottoming cycle. A parametric analysis evaluates the impact of natural gas to biomass fuel energy ratio on the electrical efficiency of various hybrid configurations. Results show that significant performance improvements with standard technology can be achieved by these hybrid configurations when compared to the reference (two independent, single-fuel power plants at the relevant scales). Electrical efficiency of natural gas energy conversion can reach up to 57–58% LHV, while the efficiency attributed to the bottoming fuel rises with up to 4 percentage points. In contrast to hybrid cycles with gas turbines as topping cycle, hybrid configurations with internal combustion engines show remarkably similar performance independent of type of configuration, at low shares of natural gas fuel input.


2019 ◽  
Vol 26 (2) ◽  
pp. 45-52
Author(s):  
Mariusz Giernalczyk

Abstract The use of gas/LNG to supply marine engines in addition to tangible economic benefits is also a method of limiting emissions of harmful substances into the atmosphere and meeting strict environmental protection regulations, especially in special areas. The technology of supplying liquid and gas fuels (Dual Fuel) is most easily used in four-stroke engines but the highest thermal efficiency is ensured by combustion two-stroke piston engines. However, in the first two-stroke dual-fuel engines, the gas supply installation was more complicated than in the four-stroke engine. It resulted, among others from the necessity of compressing the gas to high pressures (15÷30 MPa), for which extremely energy-consuming multi-stage compression systems were needed. The complicated technical system is inherently prone to failures, which is why the dual-fuel low-speed two-stroke diesel engines remained for a long period in the design and experimental phase. In recent years, there has been a significant breakthrough thanks to the introduction of new solutions with the possibility of supplying two-stroke engines with low-pressure gas (less than 1.6 MPa). In recent years, many ships powered by two-stroke, dual-fuel internal combustion engines were commissioned. Some ship-owners owning a fleet of LNG carriers with two-stroke diesel engines that so far have been powered only by liquid fuels have decided to adapt them to gas combustion. This required the adaptation of the engine for gas combustion and the expansion of the supply gas fuel system. This paper is an attempt to analyse the legitimacy of introducing two-stroke, dual-fuel internal combustion engines into the propulsion system and adaptation of engines that are already used to burn gas in them. It presents the changes introduced on one of the LNG gas carriers consisting in adapting the engine to gas combustion through modification of the cylinder head and fuel supply installation. Parameter results of the modified engines obtained during sea trials have been presented. Both advantages and disadvantages resulting from gas combustion have been pointed out. Finally, the possibility of this solution application to other LNG carriers was assessed.


Author(s):  
Hongsheng Guo ◽  
Brian Liko ◽  
Luis Luque ◽  
Jennifer Littlejohns

The combustion of natural gas reduces fuel cost and generates less emissions of carbon dioxide and particulate matter (PM) than diesel and gasoline. Replacing diesel by natural gas in internal combustion engines is of great interest for transportation and stationary power generation. Dual fuel combustion is an efficient way to burn natural gas in internal combustion engines. In natural gas–diesel dual fuel engines, unburned hydrocarbon emissions increase with increasing natural gas fraction. Many studies have been conducted to improve the performance of natural gas–diesel dual fuel engines and reported the performance of combustion and emissions of regulated pollutants and total unburned hydrocarbon at various engine operating strategies. However, little has been reported on the emissions of different unburned hydrocarbon components. In this paper, an experimental investigation was conducted to investigate the combustion performance and emissions of various unburned hydrocarbon components, including methane, ethane, ethylene, acetylene, propylene, formaldehyde, acetaldehyde, and benzaldehyde, at a low engine load condition. The operating conditions, such as engine speed, load, intake temperature, and pressure, were well controlled during the experiment. The combustion and emissions performance of pure diesel and natural gas–diesel dual fuel combustion were compared. The effect of diesel injection timing was analyzed. The results show that appropriately advancing diesel injection timing to form a homogeneous charge compression ignition (HCCI)-like combustion is beneficial to natural gas–diesel dual fuel combustion at low load conditions. The emissions of different unburned hydrocarbon components changed in dual fuel combustion, with emissions of some unburned hydrocarbon components being primarily due to the combustion of natural gas, while those of others being more related to diesel combustion.


Author(s):  
Hongsheng Guo ◽  
Brian Liko

Diesel engines have been widely used due to the higher reliability and superior fuel conversion efficiency. However, they still generate significant amount of carbon dioxide (CO2) and particulate matter (PM) emissions. Natural gas is a low carbon and clean fuel that generates less CO2 and PM emissions than diesel during combustion. Replacing diesel by natural gas in internal combustion engines help reduce both CO2 and PM emissions. Natural gas – diesel dual fuel combustion is a practical and efficient way to replace diesel by natural gas in internal combustion engines. One concern for dual fuel combustion engines is the diesel injector tip temperature increase with increasing natural gas fraction. This paper reports an experimental investigation on the diesel injector tip temperature variation and combustion performance of a natural gas – diesel dual fuel engine at medium and high load conditions. The natural gas fraction was changed from zero to 90% in the experiment. The results suggest that the injector tip temperature increased with increasing natural gas fraction at a given diesel injection timing or with advancing the diesel injection timing at a given natural gas fraction. However, the injector tip temperature never exceeded 250 °C in the whole experimental range. The effect of natural gas fraction on combustion performance depended on engine load and diesel injection timing.


1992 ◽  
Vol 114 (3) ◽  
pp. 480-487 ◽  
Author(s):  
D. T. Blizzard ◽  
F. S. Schaub ◽  
J. G. Smith

NOx emission legislation requirements for large-bore internal combustion engines have required engine manufacturers to continue to develop and improve techniques for exhaust emission reduction. This paper describes the development of the Cooper-Bessemer Clean Burn™ gas-diesel (dual-fuel) engine that results in NOx reductions of up to 92 percent as compared with an uncontrolled gas-diesel engine. Historically, the gas-diesel and diesel engine combustion systems have not responded to similar techniques of NOx reduction that have been successful on straight spark-ignited natural gas burning engines. NOx levels of a nominal 1.0 g/BHP-h, equal to the spark-ignited natural gas fueled engine, have been achieved for the gas-diesel and are described. In addition, the higher opacity exhaust plume characteristic of gas-diesel combustion is significantly reduced or eliminated. This achievement is considered to be a major breakthrough, and the concept can be applied to both new and retrofit applications.


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