Effect of mixing chamber venturi,injection timing,compression ratio and EGR on the performance of dual-fuel engine operated with HOME and CNG

Stringent environmental policies and the ever increasing demand for energy have triggered interest in novel combustion technologies that use alternative fuels as energy sources. Of these, pilot-ignited compressed natural gas (CNG) engines that employ small biodiesel pilot to ignite a premixed natural gas–air mixture have received considerable attention. This paper discusses the effect of mixing chamber venturi, injection timing, compression ratio and exhaust gas recirculation (EGR) on the performance of dual-fuel engine operated on biodiesel derived from honge oil and is called honge oil methyl ester (HOME) and CNG. The proposed study mainly focuses on the manifold induction of CNG along with HOME injection. However, CNG can also be injected using port or direct gas injector (Lakshmanan and Nagarajan 2010, Energy 35, pp. 3172–3178). The future study will involve these methods of CNG injection. From this study, it is concluded that an advanced injection timing and an increased compression ratio resulted in increased brake thermal efficiency and reduced smoke, hydrocarbons and carbon monoxide emissions. However, nitrogen oxides (NO _x ) emission increased significantly. The increased NO _x emission was effectively reduced with EGR method. A mixing chamber venturi of 3 mm size, injection timing of 27° before top dead centre (BTDC), compression ratio of 17.5 and 10% EGR were found to be optimum for the modified compression ignition engine that was operated on CNG–HOME dual-fuel mode.     

Effect of injection timing,injector opening pressure and nozzle geometry on the performance of a compression ignition engine operated on non-edible oil methyl esters from different sources

Increasing cost of fossil fuels, environmental threats from exhaust emissions and their depleting nature have generated intense international interest in developing renewable and alternative fuels for internal combustion engines. This study investigates the suitability of different non-edible-derived biodiesels such as cottonseed oil methyl ester (COME), honne oil methyl ester (HnOME) and honge oil methyl ester (HOME) to four-stroke, single-cylinder compression ignition (CI) engine. Engine tests were conducted to study the effect of fuel injection timing (IT), fuel injector opening pressure (IOP) and injector nozzle geometry on the performance, combustion and emission characteristics of COME, HnOME and HOME in the modified CI engine. IT was varied from 19° to 27° before top dead centre (bTDC) in steps of 4° bTDC; IOP was varied from 205 to 240 bar in steps of 10 bar. Nozzle injectors of three to five holes, each of 0.3 mm size, were selected for the study. It was concluded that a retarded IT of 19° bTDC increased IOP of 230 bar, and four-hole nozzle injector of 0.3 mm size resulted in overall better engine performance with increased brake thermal efficiency and reduced hydrocarbon and carbon monoxide smoke emissions for the fuels tested.     

Studies on the use of low-volatile non-edible oils in a thermal barrier-coated diesel engine

Owing to the ever-increasing vehicle population, the consumption of diesel fuel in the transportation, agricultural and industrial sectors has increased at an alarming rate. This has led to rapid fossil fuel depletion, ozone depletion and environmental degradation, which have become a serious concern. Search for alternative renewable and clean energy fuel sources to mitigate the emissions of greenhouse gases is continuing, and attempts to find different techniques for efficient utilization of these fuels are also undertaken. Biodiesel being an oxygenated fuel obtained from vegetable oils has received greater attention over the years as a promising alternative to diesel fuel. However, vegetable oils exhibit high viscosity, poor volatility and poor cold-flow characteristics. These characteristics can cause the following problems in the engine when run for a longer duration: injector coking, severe engine deposits, filter gumming, piston ring sticking and thickening of lubrication. These problems can be eliminated or minimized by adopting suitable fuel processing techniques to obtain biodiesels from vegetable oils. The fuel processing techniques vary widely, which include transesterification, supercritical methanolysis, ultrasonic and continuous microwave-assisted transesterification methods. In the present study, the transesterification method is effectively used to obtain biodiesels from non-edible oils of honne and cotton seed. The biodiesels obtained from these oils were used in the unmodified diesel engine to check their feasibility as diesel engine alternatives. Different thermal barrier coatings (TBCs) were applied on the piston, cylinder head, and inlet and exhaust valve surfaces of the diesel engine in order to make it a fully adiabatic engine. The engine with such TBCs is called a low heat rejection engine. For the present study, the TBC of partially stabilized zirconia (PSZ) and aluminium oxide (Al₂O₃) were selected. Finally, the performance of the diesel engine fuelled with different biodiesels in both conventional and thermal barrier-coated modes was compared. The thermal barrier-coated engine with the PSZ version showed better performance with increased nitric oxide emissions when compared with the Al₂O₃ coating.     

Performance,combustion and emission characteristics of a single-cylinder,four-stroke,direct injection diesel engine operated on a dual-fuel mode using Honge oil methyl ester and producer gas derived from biomass feedstock of different origin

Renewable and alternative fuels have numerous advantages compared with fossil fuels, as they are renewable and biodegradable, and provide food and energy security and foreign exchange savings besides addressing environmental concerns and socio-economic issues. In this context, present work was carried out to investigate the feasibility of alternative and renewable fuels derived from biomass feedstock of different origin for engine applications. The present study was also extended to study the effect of producer gas composition derived from different biomass feedstock on the performance, combustion and emission characteristics of a single-cylinder, four-stroke, direct injection stationary diesel engine operated on a dual-fuel mode using Honge oil methyl ester (HOME) and producer gas induction. The performance of the engine was evaluated with a constant injection timing of 27° before top dead centre, an injection pressure of 205 bar for the diesel–producer gas combination and 230 bar for the HOME–producer gas combination and a compression ratio of 17.5. The results showed that the performance of the dual-fuel engine varies with the composition of the producer gas and depends on the type of biomass feedstock used in the gasifier. Experimental investigations on the dual-fuel engine showed that brake thermal efficiency values for the engine operated using HOME–producer gas derived from babul, neem and honge woods were found to be 17.2, 14.3 and 11.56% respectively, compared to 23.8% for diesel–producer gas operation at 80% load. However, the results showed better engine performance with lower exhaust emission levels for the operation of HOME–producer gas derived from the ordinary or babul wood compared with the operation of that derived from the neem and Honge woods. In view of this, present study reveals that use of alternative and renewable fuels for dual fuel engine can be considered as an immediate solution for the development of rural areas and emergency use in the event of severe diesel fuel shortage.     

Performance and emission characteristic studies on CRDI diesel engine fuelled with plastic pyrolysis oil blended with ethanol and diesel

ABSTRACT

This paper mainly focuses on the utilisation of plastic pyrolysis oil (PPO) and its’ blends with diesel and ethanol in different proportions in a modified diesel engine fitted with common rail direct injection (CRDI) facility. PPO was subsequently blended with diesel and ethanol and characterisation has been done. Experiments were conducted to investigate the impact of injection timing (IT) and injection pressure (IP) on the performance of modified CRDI engine fuelled with PPO and its blends with diesel and ethanol. From the experimental investigations, IT of 10°bTDC and IP of 900 bar were found as best operating parameters to obtain maximum brake thermal efficiency (BTE) with lowered emissions for the fuel combinations utilised in the investigations. PPO as substitute to diesel fuel could be viable if its major concern is to finding permanent resources.     

Effect of bioethanol and thermal barrier coating on the performance of dual fuel engine operating on Honge oil methyl ester (HOME) and producer gas induction

Alternative fuels have numerous advantages compared to fossil fuels as they are renewable, biodegradable; provide energy security and foreign exchange saving besides addressing environmental concerns and socio-economic issues as well. Renewable fuels can be used predominantly as fuel for both transportation and power generation applications. Improved engine performance with reduced engine exhaust emissions is a major research objective in engine development. Today, the use of biomass derived producer gas is more relevant for addressing rural power generation and is a promising technique for controlling both nitric oxide (NO_x) and soot emission levels. In view of this, exhaustive experiments on the use of Honge oil methyl ester (HOME)–Producer gas in a dual fuel engine have been carried out with an intension of improving its fuel efficiency. This paper mainly presents results on a single cylinder four stroke direct injection diesel engine operated in dual fuel mode using HOME–Producer gas combination with and without bio-ethanol addition and thermal barrier coating (TBC). Further, the results were compared with diesel–producer gas mode of operation. Experimental investigation on dual fuel operation using HOME+5% bioethanol (BE5)–Producer gas operation with TBC showed 12.35% increased brake thermal efficiency with decreased hydrocarbon and carbon monoxide emissions and increased NO_x emission levels compared to HOME–Producer gas mode of operation.     

Effects of EGR on performance and emissions of a diesel engine fuelled with balanites aegyptiaca/diesel blends

In this study, balanites Aegyptiaca (L.) Del biodiesel was blended in proportions of 10% and 20% on the volume basis with diesel fuel and tested in a single cylinder, VCR diesel engine under measured load conditions with varied EGR rates (0, 10 and 20%). The results showed that B10 and B20 blends shown a significant reduction rate in terms of NO_x emissions that were familiar with biodiesel blends. At peak load conditions, BTE increased slightly for test fuel blends compared with pure diesel fuel while the BSFC rate and EGT suffered from increasing and decreasing nature with respect to blending percentage. From the emissions point of view, with the increase in blends percentage, a significant reduction rate is observed in terms of CO and HC concentrations (up to 12.34 and 17.5%, respectively) while NOx emissions decreased at peak load conditions (up to 24.34%). HC and CO emissions decreased with increase in blends percentage. However, lower levels of NO_x and EGT (up to 21.37 and 8.47%, respectively) and the average increase in terms of BTE and BSFC (up to 2.83 and 2.9%, respectively) can be realised with B20 test fuel blend under 20% EGR rate.