scholarly journals INVESTIGATION ON THE AIR-GAS CHARACTERISTICS OF AIR-HYDROGEN MIXER DESIGNED FOR DUAL FUEL – ENGINES

Author(s):  
Alaulddin A. Kazum ◽  
Osam H. Attia ◽  
Ali I. Mosa ◽  
Nor Mariah. Adam

High smoke emissions, nitrogen oxide and particulate matter typically produced by diesel engines. Diminishing the exhausted emissions without doing any significant changes in their mechanical configuration is a challenging subject. Thus, adding hydrogen to the traditional fuel would be the best practical choice to ameliorate diesel engines performance and reduce emissions. The air hydrogen mixer is an essential part of converting the diesel engine to work under dual fuel mode (hydrogen-diesel) without any engine modification. In this study, the Air-hydrogen mixer is developed to get a homogenous mixture for hydrogen with air and a stoichiometric air-fuel ratio according to the speed of the engine. The mixer depends on the balance between the force exerted on the head surface of the valve and the opposite forces (the spring and friction forces) and its relation to decrease and increase the fuel inlet. Computational fluid dynamics (CFD) analysis software was utilised to study the hydrogen and airflow behaviour inside the mixer, established by 3.2 L engine. The Air-hydrogen mixer is examined with different speeds of engine1000, 2000, 3000 and 4000 RPM. Results showed air-hydrogen mixture was homogenous in the mixer. Furthermore, the stoichiometric air-fuel ratio was achieved according to the speed of the engine, the developed mixer of the AIR-Hydrogen mixing process provides high mixing homogeneity and engines with stoichiometric air-fuel ratios, which subsequently contributes to the high levels of efficiency in engine operation. In summary, the current study intends to reduce the emissions of gases and offer a wide range of new alternative fuels usage. While the performance of the diesel engine with the new air-hydrogen mixer needs to be tested practically.

2015 ◽  
Vol 4 (1) ◽  
pp. 1-10 ◽  
Author(s):  
D.N. Basavarajappa ◽  
N. R. Banapurmath ◽  
S.V. Khandal ◽  
G. Manavendra

For economic and social development of any country energy is one of the most essential requirements. Continuously increasing price of crude petroleum fuels in the present days coupled with alarming emissions and stringent emission regulations has led to growing attention towards use of alternative fuels like vegetable oils, alcoholic and gaseous fuels for diesel engine applications. Use of such fuels can ease the burden on the economy by curtailing the fuel imports. Diesel engines are highly efficient and the main problems associated with them is their high smoke and NOx emissions.  Hence there is an urgent need to promote the use of alternative fuels in place of high speed diesel (HSD) as substitute. India has a large agriculture base that can be used as a feed stock to obtain newer fuel which is renewable and sustainable. Accordingly Uppage oil methyl ester (UOME) biodiesel was selected as an alternative fuel. Use of biodiesels in diesel engines fitted with mechanical fuel injection systems has limitation on the injector opening pressure (300 bar). CRDI system can overcome this drawback by injecting fuel at very high pressures (1500-2500 bar) and is most suitable for biodiesel fuels which are high viscous. This paper presents the performance and emission characteristics of a CRDI diesel engine fuelled with UOME biodiesel at different injection timings and injection pressures. From the experimental evidence it was revealed that UOME biodiesel yielded overall better performance with reduced emissions at retarded injection timing of -10° BTDC in CRDI mode of engine operation.


2021 ◽  
pp. 79-86
Author(s):  
O. Hrabovenko ◽  
S. Dotsenko ◽  
V. Nesterenko ◽  
I. Shvets

While being highly fuel-efficient, diesel engines are defined by relatively high emissions, which have a negative impact on people and the environment. In the future, most European countries plan to abandon the use of diesel engines after 2030. One way to use this type of engines is to convert them to alternative fuels from renewable energy sources, such as vegetable oils (rapeseed, sunflower and soya bean oils). A significant advantage of vegetable oils is that when they hit the ground, they break down in a couple of weeks. Sulfur oxides are virtually absent due to the small amount of sulfur in vegetable oils in the engine exhaust gases. Other environmental factors include reduced emissions of nitrogen oxides NOx, carbon monoxide CO, unburned hydrocarbons and carbon black C. However, it should be noted that the use of vegetable-based fuel involves problems related to fuel preparation, consideration of physical and chemical properties and proper engine operation and use of arable land for the cultivation of vegetable oils. The article presents the results of experimental studies to determine the effective performance of soybean oil, six cylinder, four-stroke supercharged diesel engine (26 – the diameter of the cylinder, cm; 34 – the piston stroke, cm) produced by "Pervomaiskdieselmash", which is a part of the stationary diesel generator (DGA-900) with the capacity of 900 kW. This diesel engine is with an undivided combustion chamber ("Geselman" type), gas turbine supercharging and intermediate charge air cooling. Soybean oil is more viscous and has better lubrication properties of conjugated vapors and engine components, as a result, the lifespan of the engine and high-pressure fuel pump increases by an average of 60%. However, more viscous soybean oil impairs fuel mixing, spraying and combustion. Starting qualities of the engine also deteriorate. On the other hand, as the temperature rises, the viscosity of soybean oil decreases sharply. The reasons which led to the emergence of the above-mentioned problems have been analysed. In addition, the features and advantages of the cogeneration power plant have been described, which makes it possible to obtain two forms of useful energy at the output such as thermal and electric. The use of cogeneration significantly increases the overall efficiency of the plant; it provides significant opportunities for efficient heat utilization and achieving maximum economic effect.


2021 ◽  
Vol 13 (5) ◽  
pp. 2773
Author(s):  
Sergejus Lebedevas ◽  
Tomas Čepaitis

The publication research task is related to one of the solution aspects in reference to decarbonization of transport by transferring the operation of diesel engines to natural gas. The results of converted diesel engines into operation with dual-fuel (D-NG) without significant constructive modifications are focused on forecasting the energy efficiency parameters of in-service engine models and evaluation of the reserves improvement. This paper presents energy efficiency parameters and characteristics of the combustion cycle methodological optimization of high-speed 79.5/95.5 mm diesel engine with a conventional fuel injection system. Interrelations between the indicated efficiency (ηi), combustion cycle performance parameters (excess air ratio (α), compression ratio (ε), degree of pressure increase in the cylinder (λ), maximum cycle pressure (pmax), air pressure (pk), air temperature (Tk) after compression, etc.), and heat release characteristics were determined and researched. Directions of the optimization when the engines were operating in a wide range of load (pmi) modes were also obtained: the low energy efficiency in the low-load mode were due to reduced heat release dynamics (combustion time increased up to 200° CA). The main influencing factors for ηi were the pilot-injection portion phase (φinj) and α, optimization of ε was inefficient. To avoid exceeding the permissible limits of reliability for pmax, the realized reserve of ηi increase was estimated as 10%. Methodological tools for the practical application of parametric analysis to the conversion of diesel to dual-fuel operation have been developed and adapted in the form of a numerical modeling algorithm, which was presented in nomogram form. For improvement of initial energy parameters for a specific engine models heat release characteristics identification, accurate methods must be used. The proposed methodology is seen as a theoretical tool for a dual-fuel conversion models for in-service engines and has benefit of a practical use of a fast application in the industrial field.


2021 ◽  
pp. 28-32
Author(s):  
VALERIY L. CHUMAKOV ◽  

The paper shows some ways to improve the environmental characteristics of a diesel engine using gaseous hydrocarbon fuel and operating the engine in a gas-diesel cycle mode. Some possibilities to reduce toxic components of exhaust gases in a gas-diesel engine operating on liquefi ed propane-butane mixtures have been studied. Experiments carried out in a wide range of load from 10 to 100% and speed from 1400 to 2000 rpm showed that the gas-diesel engine provides a suffi ciently high level of diesel fuel replacement with gas hydrocarbon fuel. The authors indicate some eff ective ways to reduce the toxicity of exhaust gases. The engine power should be adjusted by the simultaneous supply of fuel, gas and throttling the air charge in the intake manifold. This method enriches the fi rst combusting portions to reduce nitrogen oxides and maintains the depletion of the main charge within the fl ammability limits of the gas-air charge to reduce carbon monoxide and hydrocarbons. The authors found that when the engine operates in a gas-diesel cycle mode, the power change provides a decrease in nitrogen oxide emissions of gas-diesel fuel only due to gas supply in almost the entire load range as compared to the pure diesel. At high loads (more than 80%) stable engine operation is ensured up to 90% of diesel fuel replaced by gas. Even at 10% of diesel fuel used the concentration of nitrogen oxides decreases by at least 15…20% as compared with a diesel engine in the entire load range. However, there is an increased emission of hydrocarbons and carbon monoxide in the exhaust gases. Further experimental studies have shown that optimization of the gas diesel regulation can reduce the mass emission of nitrogen oxides contained in exhaust gases in 2…3 times and greatly reduce the emission of incomplete combustion products – carbon monoxide and hydrocarbons.


Author(s):  
T. Lakshmanan ◽  
A. Khadeer Ahmed ◽  
G. Nagarajan

Gaseous fuels are good alternative fuels to improve the energy crisis of today’s situation due to its clean burning characteristics. However, the incidence of backfire and knock remains a significant barrier in commercialization. With the invention of latest technology, the above barriers are eliminated. One such technique is timed injection of water into the intake port. In the present investigation, acetylene was aspirated in the intake manifold of a single cylinder diesel engine, with a gas flow rate of 390 g/h, along with water injected in the intake port, to overcome the backfire and knock problems in gaseous dual fuel engine. The brake thermal efficiency and emissions such as NOx, smoke, CO, HC, CO2 and exhaust gas temperature were studied. Dual fuel operation of acetylene induction with injection of water results in lowered NOx emissions with complete elimination of backfire and knock at the expense of brake thermal efficiency.


Fuel ◽  
2010 ◽  
Vol 89 (2) ◽  
pp. 438-456 ◽  
Author(s):  
Octavio Armas ◽  
Kuen Yehliu ◽  
André L. Boehman

2005 ◽  
Vol 19 (2) ◽  
pp. 418-425 ◽  
Author(s):  
A. Tsolakis ◽  
J. J. Hernandez ◽  
A. Megaritis ◽  
M. Crampton

2017 ◽  
Vol 169 (2) ◽  
pp. 64-70
Author(s):  
Konrad BUCZEK ◽  
Sven LAUER

The continuously increasing mechanical and thermal loads of modern engines require optimization of the designs with incorporation of a wide range of different aspects. Application of advanced computer simulations in the development process for most engine components is well established, leading to the creation of well optimized products. However, the optimization of such design variables ike the firing order, which influences engine operation in several disciplines, is still challenging. Considering the ever increasing peak firing pressure requirements, the layout of the firing order in multi-cylinder commercial engines is an efficient way to reduce crank train / overall engine vibration and main bearing loads, whilst controlling engine balancing and preserving adequate gas exchange dynamics. The proposed general firing order selection process for four-stroke engines and, in particular, its first part being the optimization of the firing order based on crank train torsional vibration, is the main topic of this paper. The exemplary study for a V20 high speed commercial Diesel engine regarding the influence of the firing sequence on crank train torsional vibration has been conducted with the multibody dynamics simulation software “FEV Virtual Engine”. It addresses various engine crankshaft layouts and engine applications.


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