Experimental feasibility investigation of methanol as a fuel for compression ignition engines

ABSTRACTAchieving the new emission norms is a difficult task to today’s compression ignition (CI) engine without any exhaust gas after-treatment technologies. It is necessary to find the practical method which reduces the unsafe emission, with minor modifications of the CI engine. Dual fuel homogeneous charge compression ignition (HCCI) engine has been recognised as one of the solutions to minimise the emissions and achieve higher performance. In the present study the dual fuel HCCI engine mode of operation carried out by supply of ethanol fuel-air mixture to the engine cylinder through the carburetor and diesel fuel is directly injected at the end of compression for the initiation of ignition. Dual fuel HCCI engine is one of the most promising engines suitable for alternative fuels and lower NOX emissions. An experimental investigation is carried out on dual fuel HCCI engine. Fuel consumption and exhaust emissions such as NOX, CO2, CO, HC are measured and compared with conventional CI engine. The results show that NOX emission tends to decrease at low and moderate loads of the engine, but at full load condition it is slightly higher. Further, thermal efficiency is calculated and compared in CI engine; it is observed that there is a slight improvement in thermal efficiency at high load operation. In the dual fuel HCCI engine mode, there is a provision to use of ethanol or any other alternate fuel for better energy efficiencies and low NOX emission.

Alternative fuels can be produced from both non-edible feedstocks and edible crops. The higher production costs and contaminating nature of vegetable biofuels, which cause engine component failure, make it conceivable to encourage the synthesis of biodiesel from non-edible sources. One of the most widely utilized alternative fuels is Jatropha biofuel, which has performance levels comparable to diesel fuels and can be used with CI (Compression Ignition) engines without any modifications. However when it comes to oxidative stability properties that impact shelf life and commercialization, the majority of biodiesels—including Jatropha—are lacking. Therefore, the objective of this study was to enhance the oxidative stability and other physicochemical parameters, such performance and emission characteristics, of Jatropha biodiesel with diesel blends by adding additives like DEE (diethyl ether) and MA (moringa oleifera antioxidant). The seeds of jatropha and moringa were harvested by hand and then mechanically extracted with a screw press. A conical flask containing the precisely weighed amount of oil is filled with 50 mL of neutral alcohol. The combination is then heated for an hour using a water condenser over a bath. Using phenolphthalein indicator, the contents are titrated with KOH solution after cooling. Weight of oil taken (w)/volume of KOH used (mL) × normality of KOH is the formula used to determine the acidity value of jatropha oil. It is therefore below the minimum level set by ASTM D 675, which is 2.5 mg KOH/g. Methanol was used in the transesterification process to produce biodiesel, and potassium hydroxide (KOH) was used as a catalyst. Then, using 5 % DEE and 10 % MA additives, the physicochemical properties of jatropha biodiesel—such as density, kinematics viscosity, calorific value, and oxidative stability—were characterized. The percentage of improvement of the biodiesel's mentioned properties with these additives was 0.68 %, 2.8 %, 0.73 %, and 33.8 %, respectively. The brake thermal efficiency (BTE) of B40MA10DEE05D45 increased by 8.52 % whereas the brake specific fuel consumption (BSFC) of B50MA10DEE05D35, which is Made up of 44 % diesel, 50 % jatropha biodiesel, 5 % DEE, and 10 % MA fuels, declined by 5.14 %. As a result of these additions, the blended fuel's CO, HC, and NOx emissions were reduced by 3.51 %, 2.25 %, and 8.64 %, respectively. Therefore, a 20 % blend of Jatropha biodiesel and diesel containing antioxidants from Moringa can be used in compression ignition engines without the need for engine modifications and with high oxidation stability.

Major portion of today’s energy demand in the world is being satisfied with fossil fuels. On the record of confronting the energy crisis, bio fuels have been utilized as a promising source of fuel for IC Engines. This research work is to prove that with necessary modifications in Compression Ignition (CI) engine, the efficiency can be improved and it can be made equivalent or still better than mineral diesels. An experimental investigation was made to evaluate the performance and emission characteristics of a diesel engine using different blends of pumpkin seed oil with cerium oxide and nano particle as additive in diesel. Pumpkin seed oil was blended with diesel in proportions of 10%, 20%, and 30% by volume. Performance and emission parameters were studied under different loading conditions in CI engines.

The atmospheric carbon dioxide (CO 2 ) concentration has reached its elevated peak, a severe threat to the world. Post‐combustion CO 2 capture is the most crucial method to mitigate CO 2 emissions. Recently, the biomass‐based adsorbent used in the adsorption technique has grabbed the great attention of the scientific communities. The adsorbent‐packed post‐combustion carbon capture unit can easily integrate with the existing working system without affecting efficiency. In the present research study, an experimental investigation has been conducted on biomass‐derived adsorbent to explore the feasibility of CO 2 adsorption performance from the exhaust of a compression ignition (CI) engine. As a first step, rice husk is chosen as a suitable raw material to produce activated carbon using simultaneous carbonization and activation. As a second step, the prepared activated carbon material is subjected to distinctive characterization and analytical approaches to determine its surface aspects and physical and chemical characteristics. As a third step, the sample is loaded in‐built of the capture unit and connected to the system. The main findings of the experimental test results are compared using the adsorbent capture efficacy with two distinct test fuels employed in the CI engine. The experimental outcomes show that the maximum CO 2 adsorption is achieved by about 24% and 28% for D2 quality diesel and Jatropha methyl ester biodiesel fuel operations, respectively, at normal operating conditions.

Alternative fuels for compression ignition (CI) engines are required due to supply crisis and reducing global warming caused by conventional fossil fuels. Direct utilization of straight vegetable oils in CI engines is the technically simplest route for replacing fossil fuels which does not require any additional fuel processing infrastructure. Problems related to larger viscosity and lower volatility of straight vegetable oils (SVOs) can be reduced by blending them with mineral diesel and preheating. Performance, emission and combustion characteristics of preheated and unheated Jatropha oil blends are described in this report for exploring the route of straight vegetable oil utilization in CI engines. Experimental investigations in an unmodified CI engine designed for mineral diesel showed that thermal efficiency of lower concentration blends (up to 10 %) was comparable to mineral diesel. Unburned hydrocarbon, carbon monoxide and nitrogen oxide emissions were comparable to mineral diesel. Preheating the Jatropha oil by exhaust gas heat improved the thermal efficiency and reduced unburned hydrocarbon, carbon monoxide and smoke opacity emissions but increased the nitrogen oxide emissions in comparison to unheated Jatropha oil.

Combustion and performance characteristics of CI (compression ignition) engine running with biodiesel

The Heavy Duty Diesel or compression ignition (CI) engine plays an important economical role in societies all over the world. Although it is a fuel efficient internal combustion engine design, CI engine emissions are an important contributor to global pollution. To further reduce engine emissions and improve fuel efficiency, modification of the fuel composition is an interesting option. First of all, a (partial or gradual) change over to synthetic fuels can reduce the dependency on fossil fuel, which enables reduction of CO2 emission if renewable feedstock is used. Secondly, modification of the fuel composition potentially can benefit the CI engine's emission tradeoff between particulate matter (PM) and nitric oxides (NOx). The aim of the present work is to give further insight into fuel composition impact on CI engine combustion and resulting emissions. It is shown that fuel composition changes are a powerful instrument to change the PM - NOx tradeoff on existing CI engine designs. Modern CI engines inject liquid fuel into the combustion chamber of the engine. This happens typically at high hydraulic pressure (up to 250 MPa), using a fuel injector with typically 6 to 9 injector holes during a very short time (<3 ms), very close to the end of the compression stroke of the engine. To create fundamental understanding of the CI engine combustion characteristics, the fuel spray vaporization and combustion phenomenology needs to be studied in detail. To do so, an optically accessible constant volume cell EHPC (Eindhoven High Pressure Cell) is used in this work. To facilitate the investigations, the EHPC was further developed to create engine like conditions using the pre-combustion method. This method uses a premixed combustion and by adjusting the mixture composition of the premixed gases, the residual gas mixture composition and properties can be tuned. This means that at the moment of fuel injection, during the cool down period after the pre-combustion event, non-reacting or reacting sprays can be studied. This method allows coverage of ambient conditions in this work up to a gas density of 32 kg/m3 for a temperature range of 750 to 1200 K and oxygen concentrations between 0 and 21 volume percent. To characterize the fuel spray using the EHPC, optical diagnostics and image analysis methods have been developed. Schlieren is used to investigate non-reacting spray penetration and angle dispersion. The liquid core behavior of vaporizing sprays is measured using MIE scattering. To validate the results, regular automotive CI engine fuel is used (EN590). Comparing the non-reacting EN590 fuel spray results with literature data, shows that in general the spray behavior as function of ambient conditions is in line with the trends reported. Detailed analysis reveals that, for the data captured in this work, the often used power law to describe spray penetration is not accurate enough. The spray dispersion angle at one condition is out of the expected range and more experimental data is required to get more understanding and better statistics. This outlier also slightly affects the validation of the liquid length measured using laser MIE scattering at this specific condition. When the measured data is compared with a predicted liquid length using a mixing-limited vaporization model, the liquid length is shorter than expected. The general trend in the results is however still present. For reacting fuel spray characterization the ignition delay is measured using a pressure measurement and laser line of sight extinction is use to qualify the soot presence during quasi-steady state combustion. The results achieved with both methods are in line with results from literature. It can be concluded that the EHPC, the optical diagnostics used and image analysis methods are successfully implemented and validated using EN590 fuel. With this setup and tools at hand, two additional fuels were characterized: SMDS, which is a synthetic gas to liquid fuel, and SMDS blended with 29.3 mass percent Tripropylene G lycol Monomethyl Ether (TPG ME), called fuel S-TP-9. The latter results in an oxygenated fuel with 9.4 9 mass percent oxygen. B oth fuels show differences compared to EN590, especially for reacting fuel sprays. The higher Cetane Number of both fuels results in an, expected, reduced ignition delay. B oth fuels produce less soot during quasi-steady state combustion. O xygenated fuel S-TP-9 clearly shows an even lower soot production compared to SMDS. At reduced ambient temperatures and oxygen concentration soot production for all tested fuels is reduced, but the additional soot production reduction for S-TP-9 is less significant compared to the results at an ambient oxygen concentration of 21 volume percent. Additional to the fuel spray combustion investigations using the EHPC, a broader range of fuels was tested on Heavy Duty CI engine test rig to quantify the effects of fuel composition. The results show that oxygenated fuels up to 15 mass percent oxygen can reduce engine-out PM emission up to one order of magnitude at reduced in-cylinder temperatures and oxygen concentration. The other effects of fuel composition are limited to a minor impact on injection duration, apparent heat release and NOx emission. The results of engine and EHPC combined suggest that the beneficial influence of additional oxygen in the fuel on PM emissions, becomes even more effective after end of combustion, during the late expansion phase of the engine. How this process evolves up to the moment the PM emissions are measured in the exhaust system of the engine, should be part of further investigation.

Experimental investigations on effect of different compression ratios on enhancement of maximum hydrogen energy share in a compression ignition engine under dual-fuel mode

The compression ignition and small displacement spark-ignition engines play an important role in the urban air pollution. In particular, vehicles equipped with compression ignition engines are widely used because of their higher performance and fuel efficiency with respect to the spark-ignition ones. Nevertheless, spark-ignition engines with low displacements are even more wide-spreading because of the lower fuel consumption and emissions. They are also used for two-wheeled vehicles, whose easier navigation makes them widely used in heavily congested areas. Their contribution on urban pollution is worsened by the fact that these vehicles have to comply with the Euro 3 standard; light vehicles have, instead, to fulfill the more restrictive Euro 6, which for the compression ignition and gasoline direct injection engines indicates for particle emissions also a number-based regulation. This article aims to characterize the effects of biofuels on engine emissions and performance of compression ignition and spark-ignition engines. The investigation was carried out on different class of engines. Direct injection and a port fuel injection spark-ignition engines fueled with ethanol and its blends, 10 v/v%, 50 v/v% and 85 v/v% of ethanol in gasoline. The compression ignition engine was equipped with a common rail injection system and was fueled with pure rapeseed methyl ester, representative of fatty acid methyl ester, and its blends in diesel, 20 v/v% and 50 v/v%. The gaseous emissions and the particle concentration were measured at the exhaust by means of conventional instruments. Particle size distribution function was measured in the range from 5.6 to 560 nm by means of an engine exhaust particle sizer. A comprehensive characterization of the particulate carbon was performed by means of optical diagnostics in the combustion chamber. In particular, two-dimensional images of flame evolution were detected and processed by two-color pyrometry technique to assess the in-cylinder soot formation and oxidation processes. For both the investigated spark-ignition and compression ignition engines, the use of biofuels shows a partial increase in the specific fuel consumption and a reduction of the soot particles emission. Nevertheless, a further effort on engine technology should be paid to balance the mass with the size and number of the particles.

Optimization of EGR effects on performance and emission parameters of a dual fuel (Diesel + CNG) CI engine: An experimental investigation

Low energy density fuels, like producer gas from biomass gasification, can be profitably used in compression ignition (CI) engines by means of a proper combustion strategy, such as the dual-fuel mode. Experimental investigations have proven the environmental benefits of the use of producer gas in terms of green-house gas emissions but critical issues related to their use in CI engines have been also highlighted. In particular, under specific operating conditions, the performance and the emissions of the engine might be derated reducing the attractiveness of the technology. In this work a new data-driven emission optimization strategy for a micro-cogeneration system based on an open-top biomass gasification unit coupled with a CI engine running in dual-fuel mode (producer gas/diesel) is presented and discussed. The main purpose of the work is to provide an appropriate tool to address one of the typical problems of dual-fuel systems, namely the nitrogen oxides (NOx) and carbon monoxide (CO) emission trade-off, by calculating the optimal diesel substitution rate (DSR) at a certain required power load. The methodology baseline is the experimental characterization and parametric modeling of the system in terms of NOx, CO, and electrical efficiency (ηe). Then a trade-off objective function (TOF) is defined. The novelties of the proposed approach stands in the building of an ad-hoc designed TOF so as to describe the problem with a single-objective optimization, and thus avoiding the computational and time complexity of a multi-objective optimization. Moreover, a second peculiar aspect is the introduction in the TOF of an internally dependent coefficient (namely the load factor Kl) able to take into account the effect of load and DSR on CO emissions: the adding of such a physical-related feature represents an effective enrichment of the minimization strategy, especially considering the nature of the optimization, which is purely data-driven. Finally, sequential quadratic programming (SQP) minimization of the TOF is carried out by means of the available MATLAB SQP libraries, and two optimization strategies – namely, CO-driven and efficiency-driven - are discussed. Results show (i) promising potentialities in identifying the best effective utilization range of dual-fuel combustion; (ii) high flexibility in the use of the optimization algorithm thanks to the definition of the TOF, which can be easily adapted to different objectives (e.g., NOx mitigation, maintenance of high electrical efficiencies, CO emission bounding) while maintaining external constraints; (iii) high robustness even in the extreme cases in which the imposition of a particular constraint (e.g., high electrical efficiency) is not compatible with the capabilities of the system.

In recent years, hybrid fuels have gained more popularity as a substitute fuel for petro‐diesel over biodiesel, due to their comparable properties, renewable nature, and easy processing. The main objective of this study is to experimentally investigate the combined effect of injection timings (ITs) (21, 23, and 25° before top dead center [BTDC]) and injection pressures (IPs) (200, 250, and 300 bar) on the engine characteristics of a compression ignition (CI) engine fueled with hybrid fuel (HB‐1). The hybrid fuel was prepared by mixing waste cooking oil, ethanol, and n‐butanol in appropriate proportion, that is, 69:18:13 by vol %, respectively. The experimentation was carried out on a single‐cylinder CI engine having rated power of 3.5 kW, four‐stroke, eddy current loading, water‐cooled, and run at constant speed of 1500 rpm. The experimental results were obtained at 80% of full load for combustion, performance, and emission characteristics of hybrid fuel and comparison have made with original setting (IT‐23 BTDC and IP‐200 bar). The obtained results showed that advancement in IT leads to higher cylinder pressure and heat release peaks, whereas retardation leads to opposite trend as compared to the original setting. Moreover, at IT‐25° BTDC with IP‐300 bar, higher brake thermal efficiency was measured than all the altering parameters, whereas brake specific energy consumption and exhaust gas temperature were found to be increased slightly in all altering parameters as compared to original setting. The Carbon monoxide and unburnt hydrocarbon emissions increased with all the altering parameters as compared to original setting. The advancement in IT with IP‐200 bar produced higher oxides of nitrogen (NOX) level than all other altering parameters, while other ITs and IPs emitted lower NOX level as compared to original setting. The IT‐25° BTDC with IP‐200 bar produced lowest smoke opacity as compared to other altering parameters.

This study explores the impact of intake air cooling intensity, defined by heat exchanger effectiveness (HEE) and exhaust gas recirculation (EGR), on the energy and environmental performance of a turbocharged compression ignition (CI) engine. Experimental investigations were conducted on a 1.9-litre CI engine operating at 2000 rpm under three brake mean effective pressure (BMEP) conditions (0.2, 0.4, and 0.6 MPa), which correspond to part-load engine operation. HEE was varied at 0%, 50%, and 100%, in both EGR-on and EGR-off modes. Additional numerical simulations were carried out using AVL BOOST software to analyze combustion dynamics, including engine operating cycle modeling to validate the accuracy of the combustion analysis. The results demonstrate that increasing HEE significantly improves cylinder filling and excess air ratio, leading to enhanced combustion efficiency and lower in-cylinder temperatures. This, in turn, reduces specific NOx emissions by approximately 40% with EGR and approximately 60% without EGR; however, under EGR-on conditions, the reduced combustion intensity leads to increased smoke and unburned hydrocarbon emissions—particularly at high cooling intensities. This effect is primarily associated with the engine control unit’s (ECU) limitations on intake air mass flow to maintain the target EGR ratio. Integrated control of HEE and EGR systems improves engine performance and reduces emissions across varying conditions, while highlighting trade-offs that inform the refinement of air management strategies.

The present work has discussed the following characteristics like performance, combustion and emission characteristics of blends of aluminum (Al), zinc oxide (ZnO) and its mixture of nanoparticles at different ratios with diesel tested on a stationary direct injection compression ignition (CI) engine at five different loads. The fuels have been made by blending of nanoparticles with diesel at different concentrations. The results have shown that the Nano fuels have given lower brake specific fuel consumption (BSFC), higher brake thermal efficiency (BTE) and air-fuel ratio when compared with diesel. In combustion analysis, the Nano fuels have given higher heat release rate, crank angle 50 (CA50) and lower ignition delay when compared with diesel. In emission analysis, the Nano fuels have given higher nitrogen oxides (NOx) and lower carbon monoxide (CO), hydrocarbons (HC) and smoke emissions when compared with diesel. The fuel properties of nano fuels have shown that the kinematic viscosity, calorific values have been higher and flash point, fire point, density have been lower when compared with diesel.

Experimental Investigation by Varying Fuel Injection Pressure on CI Engine