Study on combustion and emissions of a turbocharged compression ignition engine fueled with dimethyl ether and biodiesel blends

In this study, combustion and emissions characteristics of a turbocharged compression ignition engine fueled with dimethyl ether (DME) and biodiesel blends are experimentally investigated. The effects of nozzle parameter on combustion and emissions are evaluated. The result shows that with the increase of DME proportion, ignition delay, the peak in-cylinder pressure, peak heat-release rate, peak in-cylinder temperature decrease, and their phases retard. Compared to the nozzle 6 × 0.40 mm, the peak cylinder pressure and peak heat-release rate are higher with nozzle 6 × 0.35 mm, and their phases are advanced. Increased DME proportion in fuel blends causes greater differences. Compared to biodiesel, NO_x emissions of blends significantly decrease; HC emissions and CO emissions increase slightly. DME–biodiesel blends can be used as an alternative in a turbocharged CI engine. To obtain low NO_x emissions and a soft engine operation, for high DME proportion blended fuels, nozzle of 6 × 0.40 mm adopted.     

Investigation on performance,combustion and emission characteristics of biodiesel - Ethanol blends with hydrogen in CI engine

The current research work focus on the utilization of hydrogen as a fuel in CI engine has been increased tremendously, since it is a zero-emission fuel. But higher self-ignition temperature than conventional fuel, makes to operate in dual fuel mode condition in CI engine. The diesel or biodiesel along with hydrogen in a CI engine results in the improvement in the performance but increase of NO. In order to minimize the NO emission, addition of ethanol with jamun B20 biodiesel blend (biodiesel-diesel-ethanol) and two ternary blends such as B20E05 and B20E10 are formed. In the present study, biodiesel along with H₂ is admitted in the CI engine. Ethanol addition reduces combustion temperature and act as cetane improver for the biodiesel. This induces better combustion of the fuel and reduce NO. The biodiesel production from jamun seed is carried out through transesterification process. H₂ of 4 lpm is allowed at the air inlet and jamun B20 blend is injected through the fuel injector. Improvement of brake thermal efficiency and increase in the NO are observed for the hydrogen with biodiesel operated CI engine. The performance and emission behaviors of CI engine done for the test samples. At full load condition (ternary blend) B20E05 assisted H₂ shows the drastic reduction of NO emission of 8.2% than B20 assist H₂ blend. In other hand emission like hydrocarbon, carbon monoxide and smoke opacity show a notable reduction for B20E05 blend assist H₂ than other test sample fuel. The thermal efficiency is 30.98% for B20E05 assist H₂ and it is 7.55% and 4.7% higher than B20 and B20E05 assist H₂ blend respectively.     

Effect of injection parameters on the combustion and emission characteristics in a common-rail direct injection diesel engine fueled with waste cooking oil biodiesel

The objective of this paper was to study the effects of the injection pressure and injection timing on the combustion and emission characteristics in a single-cylinder common-rail direct injection (CRDI) diesel engine fueled with waste cooking oil (WCO) biodiesel and commercial diesel fuel. The fuel property including fatty acid composition for the biodiesel were measured and compared with those of the conventional diesel fuel. The engine tests were conducted at two injection pressures (80 and 160 MPa) and different injection timings from −25 to 0 crank angle degree (CAD) after top dead center (aTDC) under two different engine loads. The results showed that the indicated specific fuel consumption (ISFC) with respect to the injection timings of the biodiesel was higher than that of the diesel fuel under all experimental conditions. The peak cylinder pressure and the peak heat release rate of the biodiesel were slightly lower, while the ignition delay was slightly longer under all operating conditions. In terms of emissions, the biodiesel had benefits in reduction of smoke, carbon monoxide (CO), hydrocarbon (HC) emissions especially with high fuel injection pressure. The nitrogen oxide (NO_x) emissions of the biodiesel were relatively higher than those of the diesel under all experimental conditions.     

A review of the effects of catalyst and additive on biodiesel production, performance, combustion and emission characteristics

This article is a literature review of the effect of different catalysts and additives on biodiesel production, performance, combustion and emission characteristics. This study is based on the reports of about 60 scientists who published their findings between 1998 and 2010. It was reported that base catalyst produced more biodiesel compared to acid type catalysts. There was not much variation in engine performance with the use of catalyst. Combustion characteristics were improved with the use of additives. It was found that ignition delay was reduced and premixed combustion duration was increased with the addition of catalyst. HC emission and PM emission were reduced with the use of catalysts.     

Effect of hydrogen enrichment on performance,combustion, and emission of a methanol fueled SI engine

The study of potentially high rated alternative fuel (Methanol) for the IC engines is an exciting topic in the recent research advancement. However, the study of combination of methanol and hydrogen is considered to address both economic and environmental needs. Hydrogen with best combustion characteristics will compensate for the drawbacks of methanol as a fuel. In the present investigation hydrogen enrichment to methanol has shown a significant enhancement in performance and combustion; the overall emission has reduced substantially. The experiments for a different set of trials, including hydrogen enrichment ranging between 5% and 20% with 2.5% increment, the engine is operated with wide-open throttle (WOT) condition for different speeds. The increase in enrichment of hydrogen has shown a rise in BTE, BP, and a reduced BSEC value. The percentage increase in BTE is between 20 and 30%, and an increase in hydrogen beyond 12.5% would affect the volumetric efficiency, and thus performance declines after that. The exhaust emissions have a huge impact on hydrogen enrichment; CO, HC, and CO₂ emission are reduced by 30–40%; however, an increase in cylinder temperature due to rapid combustion slightly increases the NO_x emission. Thus hydrogen enriched methanol operating at higher compression ratio can improve the overall engine characteristics significantly.     

Effect of nanoparticles and hydrogen on combustion performance and exhaust emission of corn blended biodiesel in compression ignition engine with advanced timing

In this study, we have evaluated the influence of Zinc oxide and Titanium dioxide nanoparticles addition in hydrogen-corn blended biodiesel combustion performance and exhaust emission using a dual direct-injection compression-ignition engine. 5% of Zinc oxide and Titanium dioxide were mixed with corn-vegetable oil methyl ester under ultrasonication. Results revealed that the addition of nanoparticles improved the Brake power by 22% (Titanium dioxide) and 4% (Zinc oxide). Consequently, 18% and 15% reduction in brake specific fuel consumption indeed at 50% load compared to neat diesel. Furthermore, the addition of nanoparticles also resulted in a reduction of emission values of 37% and 26% in hydrocarbon, 26% and 36% for carbon monoxide, 19% and 15% in nitrogen oxide and followed by 13% and 8% of smoke opacity. Therefore, the results proved that hydrogen-corn biodiesel blended with nanoparticles additive reports a positive effect on compression-ignition diesel engines without major modifications in engine.     

Performance, emission and combustion characteristics of biodiesel fuelled variable compression ratio engine

Experiments has been carried out to estimate the performance, emission and combustion characteristics of a single cylinder; four stroke variable compression ratio multi fuel engine fuelled with waste cooking oil methyl ester and its blends with standard diesel. Tests has been conducted using the fuel blends of 20%, 40%, 60% and 80% biodiesel with standard diesel, with an engine speed of 1500 rpm, fixed compression ratio 21 and at different loading conditions. The performance parameters elucidated includes brake thermal efficiency, specific fuel consumption, brake power, indicated mean effective pressure, mechanical efficiency and exhaust gas temperature. The exhaust gas emission is found to contain carbon monoxide, hydrocarbon, nitrogen oxides and carbon dioxide. The results of the experiment has been compared and analyzed with standard diesel and it confirms considerable improvement in the performance parameters as well as exhaust emissions. The blends when used as fuel results in the reduction of carbon monoxide, hydrocarbon, carbon dioxide at the expense of nitrogen oxides emissions. It has found that the combustion characteristics of waste cooking oil methyl ester and its diesel blends closely followed those of standard diesel.     

Influence of injection timing on performance,combustion and emission characteristics of Jatropha biodiesel engine

The study of effect of injection timing along with engine operating parameters in Jatropha biodiesel engine is important as they significantly affect its performance and emissions. The present paper focuses on the experimental investigation of the influence of injection timing, load torque and engine speed on the performance, combustion and emission characteristics of Jatropha biodiesel engine. For this purpose, the experiments were conducted using full factorial design consisting of (3³) with 27 runs for each fuel, diesel and Jatropha biodiesel. The effect of variation of above three parameters on brake specific fuel consumption (BSFC), brake thermal efficiency (BTE), peak cylinder pressure (P_max), maximum heat release rate (HRR_max), CO, HC, NO emissions and smoke density were investigated. It has been observed that advance in injection timing from factory settings caused reduction in BSFC, CO, HC and smoke levels and increase in BTE, P_max, HRR_max and NO emission with Jatropha biodiesel operation. However, retarded injection timing caused effects in the other way. At 15 N m load torque, 1800 rpm engine speed and 340 crank angle degree (CAD) injection timing, the percentage reduction in BSFC, CO, HC and smoke levels were 5.1%, 2.5%, 1.2% and 1.5% respectively. Similarly the percentage increase in BTE, P_max, HRR_max and NO emission at this injection timing, load and speed were 5.3%, 1.8%, 26% and 20% respectively. The best injection timing for Jatropha biodiesel operation with minimum BSFC, CO, HC and smoke and with maximum BTE, P_max, HRR_max is found to be 340 CAD. Nevertheless, minimum NO emission yielded an optimum injection timing of 350 CAD.     

A comparative study of combustion performance and emission of biodiesel blends and diesel in an experimental boiler

Recently, biodiesel has become more attractive since it is made from renewable resources and also for the fact that the resources of fossil fuels are diminishing day by day. This study compares combustion of B5, B10, B20, B50, B80 and B100 with petroleum diesel over wide input air flows at two energy levels in an experimental boiler. The comparison is made in terms of combustion efficiency and flue gas emissions (CO, CO₂, NO_X, and SO₂) and influence of air flow at two energy levels 219 kJ/h and 249 kJ/h is studied. The findings show that at higher level energy diesel efficiency was a little higher than that of biodiesel, but at lower level biodiesels are efficient than diesel. Except B10, Biodiesel and other blends emitted less pollutant CO, SO₂ and CO₂ than diesel. B10 emitted lower CO₂ and NO_X, but emitted higher SO₂ than diesel. Despite studies reporting an increase in the NO_X level resulting from burning of biodiesel over conventional petroleum diesel fuels in engines, our findings indicated at the second energy level a reduction in the NO_X level in the flue gases resulting from burning of biodiesel.     

Exhaust emission study on neat biodiesel and alcohol blends fueled diesel engine

In this study, neat biodiesel with octanol additive was employed in a diesel engine and its effects on engine emission were studied. The five fuels evaluated were neat palm kernal oil biodiesel, octanol blended with biodiesel by 10%, 20%, and 30% volume, and diesel. All the emissions are reduced by the addition of octanol in biodiesel in all loads owing to the higher oxygen concentration of air/fuel mixtures and improved atomization. Hence, it is concluded that the neat biodiesel and octanol blends can be employed as an alternative fuel for existing unmodified diesel engines owing to its lesser emission characteristics.     

Evaluating combustion,performance and emission characteristics of diesel engine using karanja oil methyl ester biodiesel blends enriched with HHO gas

With a specific end goal to take care of the worldwide demand for energy, a broad research is done to create alternative and cost effective fuel. The fundamental goal of this examination is to investigate the combustion, performance and emission characteristics of diesel engine using biodiesel blends enriched with HHO gas. The biodiesel blends are gotten by blending KOME obtained from transesterification of karanja oil in various proportions with neat diesel. The HHO gas is produced by the electrolysis of water in the presence of sodium bicarbonate electrolyte. The constant flow of HHO gas accompanied with biodiesel guarantees lessened brake specific fuel consumption by 2.41% at no load and 17.53% at full load with increased the brake thermal efficiency by 2.61% at no load and 21.67% at full load contrasted with neat diesel operation. Noteworthy decline in unburned hydrocarbon, carbon monoxide, carbon-dioxide emissions and particulate matter with the exception of NO_x discharge is encountered. The addition of EGR controls this hike in NO_x with a slight decline in the performance characteristics. It is clear that the addition of HHO gas with biodiesel blends along with EGR in the test engine improved the overall characterization of engine.     

Effect of metal based additive on performance emission and combustion characteristics of diesel engine fuelled with biodiesel

This study investigates the use of ferric chloride (FeCl₃) as a fuel borne catalyst (FBC) for waste cooking palm oil based biodiesel. The metal based additive was added to biodiesel at a dosage of 20 μmol/L. Experiments were conducted to study the effect of ferric chloride added to biodiesel on performance, emission and combustion characteristics of a direct injection diesel engine operated at a constant speed of 1500 rpm at different operating conditions. The results revealed that the FBC added biodiesel resulted in a decreased brake specific fuel consumption (BSFC) of 8.6% while the brake thermal efficiency increased by 6.3%. FBC added biodiesel showed lower nitric oxide (NO) emission and slightly higher carbon dioxide (CO₂) emission as compared to diesel. Carbon monoxide (CO), total hydrocarbon (THC) and smoke emission of FBC added biodiesel decreased by 52.6%, 26.6% and 6.9% respectively compared to biodiesel without FBC at an optimum operating condition of 280 bar injection pressure and 25.5^o bTDC injection timing. Higher cylinder gas pressure, heat release rate and shorter ignition delay period were observed with FBC added biodiesel at these conditions.     

Performance and combustion characteristic of CI engine fueled with hydrogen enriched diesel

The combustion of hydrogen–diesel blend fuel was investigated under simulated direct injection (DI) diesel engine conditions. The investigation presented in this paper concerns numerical analysis of neat diesel combustion mode and hydrogen enriched diesel combustion in a compression ignition (CI) engine. The parameters varied in this simulation included: H₂/diesel blend fuel ratio, engine speed, and air/fuel ratio. The study on the simultaneous combustion of hydrogen and diesel fuel was conducted with various hydrogen doses in the range from 0.05% to 50% (by volume) for different engine speed from 1000 – 4000 rpm and air/fuel ratios (A/F) varies from 10 – 80. The results show that, applying hydrogen as an extra fuel, which can be added to diesel fuel in the (CI) engine results in improved engine performance and reduce emissions compared to the case of neat diesel operation because this measure approaches the combustion process to constant volume. Moreover, small amounts of hydrogen when added to a diesel engine shorten the diesel ignition lag and, in this way, decrease the rate of pressure rise which provides better conditions for soft run of the engine. Comparative results are given for various hydrogen/diesel ratio, engine speeds and loads for conventional Diesel and dual fuel operation, revealing the effect of dual fuel combustion on engine performance and exhaust emissions.     

A numerical study on combustion and emission characteristics of premixed hydrogen air flames

Main challenges for micro power generators that utilize combustion process for energy production are inadequate residence time, destructive radical wall interactions and intensified heat loss which are mainly rooted from size limitation of such devices. To achieve high and uniform energy output, and bring in a solution to these challenges in an environment friendly manner without any kind of fundamental modification, effect of equivalence ratio on combustion and emission behavior of premixed hydrogen/air flames is numerically investigated in this study. For this purpose, an experimentally tested micro cylindrical combustor model is constructed and premixed hydrogen/air combustion in this model is simulated by varying equivalence ratio between 0.5 and 1.2 to find an optimal equivalence ratio with respect to drawbacks of micro power generators. Combustion and turbulence models implemented in this study are Eddy Dissipation Concept and Standard k-ε models, respectively. A detailed hydrogen/air reaction mechanism which consists of 9 species and 19 steps is employed to accurately gain insight into combustion process. Simulation results show that as the equivalence ratio decreases; centerline temperature distribution gets a lower value and the place where chemical reactions take place moves downstream. The most uniform temperature distribution is achieved between 0.8 and 1.0 equivalence ratios. The highest NO_x formation is at 0.9 equivalence ratio and its mass fraction decreases sharply when the equivalence ratio reduces from 0.9 to 0.5.     

Role of hydrogen in improving performance and emission characteristics of homogeneous charge compression ignition engine fueled with graphite oxide nanoparticle-added microalgae biodiesel/diesel blends

The development of low-temperature combustion models combined with the use of biofuels has been considered as an efficient strategy to reduce pollutant emissions like CO, HC. NO_x, and smoke. Indeed, Homogeneous Charge Compression Ignition (HCCI) is the new approach to drastically minimize NO_x emissions and smoke owing to the lower cylinder temperature and a higher rate of homogeneous A/F mixture as compared to compression ignition (CI) engines. The present research deal with the behavior analysis of a CI engine powered by diesel, Euglena Sanguinea (ES), and their blends (ES20D80, ES40D60, ES60D40, ES80D20). The experimental results revealed the highest brake thermal efficiency for ES20D80 although it decreased by 4.1% compared to diesel at normal mode. The average drop in HC, CO, and smoke was 2.1, 2.3, and 5.7% for ES20D80 as opposed to diesel fuel. Therefore, in the next stage, ES20D80 with various concentrations of graphite oxide (GO) nanoparticle (20, 40, 60, and 80 ppm) was chosen to carry out experiments in the HCCI mode, in which hydrogen gas was induced along with air through the intake pipe at a fixed flow rate of 3 lpm for the enrichment of the air-fuel mixture. As a result, the combination of hydrogen-enriched gas and GO-added ES20D80 in the HCCI mode showed similar performance to the CI engine but registered a major reduction of NO_x and smoke emissions, corresponding to 75.24% and 53.07% respectively, as compared to diesel fuel at normal mode.     

Performance and exhaust emission characteristics of a CI engine fueled with Pongamia pinnata methyl ester (PPME) and its blends with diesel

Transport vehicles greatly pollute the environment through emissions such as CO, CO₂, NO_x, SO_x, unburnt or partially burnt HC and particulate emissions. Fossil fuels are the chief contributors to urban air pollution and major source of green house gases (GHGs) and considered to be the prime cause behind the global climate change. Biofuels are renewable, can supplement fossil fuels, reduce GHGs and mitigate their adverse effects on the climate resulting from global warming. This paper presents the results of performance and emission analyses carried out in an unmodified diesel engine fueled with Pongamia pinnata methyl ester (PPME) and its blends with diesel. Engine tests have been conducted to get the comparative measures of brake specific fuel consumption (BSFC), brake specific energy consumption (BSEC) and emissions such as CO, CO₂, HC, NO_x to evaluate the behaviour of PPME and diesel in varying proportions. The results reveal that blends of PPME with diesel up to 40% by volume (B40) provide better engine performance (BSFC and BSEC) and improved emission characteristics.     

Study on combustion characteristics and particulate emissions of a common-rail diesel engine fueled with n-butanol and waste cooking oil blends

Biodiesel is a promising alternative fuel because of its renewability and extensive source of raw materials. Butanol can be blended in biodiesel to reduce the kinematic viscosity and promote the fuel atomization. In this respect, biodiesel was blended with 10% and 20% n-butanol, and the combustion characteristics and particulate emissions of the fuel blends were tested in a turbocharged, 6-cylinder, common rail diesel engine at a constant speed of 1400 rpm under seven engine loads. The experimental results show that under various engine loads, all of the butanol and biodiesel fuel blends provide faster combustion than diesel due to the higher oxygen content of n-butanol and the lower cetane number of butanol which results in stronger premixed combustion. The addition of butanol is beneficial to concentrating the heat release and thus shorten the combustion duration. With an increased proportion of butanol, soot emissions of butanol and biodiesel fuel blends decrease, the number concentration and volume concentration of ultrafine particles (UFPs) reduce noticeably. Meanwhile, the geometric mean diameters of UFPs decrease with an increase in butanol. With an increase of the engine loads, the number concentration peaks of UFPs gradually transfer from the size range of nucleation mode particles (NMPs) to the size range of accumulation mode particles (AMPs) due to the elevated combustion temperatures and high equivalence ratios. Moreover, biodiesel and fuel blends exhibit a higher percentage of NMPs as compared to diesel because of the fuel-bound oxygen, zero aromatics, and low sulfides.     

Influence of hydrogen co-combustion with diesel fuel on performance,smoke and combustion phases in the compression ignition engine

The main objective of this study was to examine impact of hydrogen addition to the compression ignition engine fueled with either rapeseed methyl ester (RME) or 7% RME blended diesel fuel (RME7) on combustion phases and ignition delay as well as smoke and exhaust toxic emissions. Literature review shows in general, hydrogen in those cases is used in small amounts below lower flammability limits. Novelty of this work is in applying hydrogen at amounts up to 44% by energy as secondary fuel to the compression ignition engine. Results from experiments show that increase of hydrogen into the engine makes ignition delay shortened that also affects main combustion phase. In all tests the trends of exhaust HC and CO toxic emissions vs. hydrogen addition were negative. The trend of smokiness decreased steadily with increase of hydrogen. Amounts of hydrogen addition by energy share were limited to nearly 35% due to combustion knock occurring at nominal load.     

Preparation,characterization, engine combustion and emission characteristics of rapeseed oil based hybrid fuels

In this study, hybrid fuels consisting of rapeseed oil/diesel blend, 1% aqueous ethanol and a surfactant (oleic acid/1-butanol mixture) were prepared and tested as a fuel in a direct injection (DI) diesel engine. The main fuel properties such as the density, viscosity and lower heating value (LHV) of these fuels were measured, and the engine performance, combustion and exhaust emissions were investigated and compared with that of diesel fuel. The experimental results showed that the viscosity and density of the hybrid fuels were decreased and close to that of diesel fuel with the increase of ethanol volume fraction up to 30%. The start of combustion was later than that of diesel fuel and the peak cylinder pressure, peak pressure rise rate and peak heat release rate were higher than those of diesel fuel. The brake specific fuel consumption (BSFC) of hybrid fuels was increased with the volume fraction of ethanol and higher than that of diesel. The brake specific energy consumption (BSEC) was almost identical for all test fuels. The smoke emissions were lower than those for diesel fuel at high engine loads, the NO_x emissions were almost similar to those of diesel fuel, but CO and HC emissions were higher, especially at low engine loads.     

Combustion and emission characteristics of a spray guided direct-injection spark-ignition engine fueled with natural gas-hydrogen blends

Combustion and emission characteristics of a spray guided direct-injection spark-ignition engine fueled with natural gas-hydrogen blends were investigated. Results show that the brake thermal efficiency increases with the increase of hydrogen fraction and it shows an increasing and then decreasing trend with advancing fuel-injection timing. For later injection timings, the beginning of heat release is advanced with increasing hydrogen fraction, while the beginning of heat release is advanced and then retarded with the increase of hydrogen fraction at earlier injection timings. The flame development duration, rapid combustion duration and total combustion duration decrease with increasing hydrogen fraction. Maximum cylinder gas pressure, maximum mean gas temperature, maximum rate of pressure rise and maximum heat release rate show an increasing and then decreasing trend with the increase of hydrogen fraction. Brake NOx emission is increased and then decreased, while brake HC, CO and CO₂ emissions decrease with the increase of hydrogen fraction.