Fueled Compression Ignition Engine Research Articles

The effect of low reactivity fuels on the dual fuel mode compression ignition engine with exergy and soot analyses

In this study, the effect of fuel injection timing of diesel on the dual fuelled compression ignition engine with gasoline, methanol and toluene has been investigated. Closed cycle combustion simulations have been conducted to complement the experiment results and for a better understanding of the in-cylinder dynamics. Second law of thermodynamics analysis has been done for the designing of energy recovery devices. Exhaust soot particles has been analysed by scanning electron microscopy to get soot particle structure. Distributions of soot particle number by size and particle mass by size have been investigated. Experiments have been conducted for respective premixed ratios of gasoline/methanol/toluene at different start of injection (SOI) timing of diesel. Outcomes revealed that the maximum gross indicated thermal efficiency (GITE) of 39% is obtained for gasoline/diesel mode. This mode shows 86% more oxides of nitrogen (NOx) in comparison with methanol/diesel mode at −25 crank angle degree (CAD) SOI case. About 54% more soot has been observed at −25 CAD SOI in toluene/diesel compared to that of gasoline/diesel mode. Maximum of 38.7% and minimum of 27.8% work exergies have been observed in gasoline/ and methanol/diesel modes respectively. Toluene/diesel mode shows the largest average primary particle diameter (Dp; 44 nm) among the dual fuel modes.

A Study on the High Load Operation of a Natural Gas-Diesel Dual-Fuel Engine

Diesel fueled compression ignition engines are widely used in power generation and freight transport owing to their high fuel conversion efficiency and ability to operate reliably for long periods of time at high loads. However, such engines generate significant amounts of carbon dioxide (CO2), nitrogen oxides (NOx), and particulate matter (PM) emissions. One solution to reduce the CO2and particulate matter emissions of diesel engines while maintaining their efficiency and reliability is natural gas (NG)-diesel dual-fuel combustion. In addition to methane emissions, the temperatures of the diesel injector tip and exhaust gas can also be concerns for dual-fuel engines at medium and high load operating conditions. In this study, a single cylinder NG-diesel dual-fuel research engine is operated at two high load conditions (75% and 100% load). NG fraction and diesel direct injection (DI) timing are two of the simplest control parameters for optimization of diesel engines converted to dual-fuel engines. In addition to studying the combined impact of these parameters on combustion and emissions performance, another unique aspect of this research is the measurement of the diesel injector tip temperature which can predict potential coking issues in dual-fuel engines. Results show that increasing NG fraction and advancing diesel direct injection timing can increase the injector tip temperature. With increasing NG fraction, while the methane emissions increase, the equivalent CO2emissions (cumulative greenhouse gas effect of CO2and CH4) of the engine decrease. Increasing NG fraction also improves the brake thermal efficiency of the engine though NOx emissions increase. By optimizing the combustion phasing through control of the DI timing, brake thermal efficiencies of the order of ∼42% can be achieved. At high loads, advanced diesel DI timings typically correspond to the higher maximum cylinder pressure, maximum pressure rise rate, brake thermal efficiency and NOx emissions, and lower soot, CO, and CO2-equivalent emissions.

RSM-Based Parameter Optimization of Compression Ignition Engine Fueled with Diesel Blended with Two Biofuels: Rice Bran and Karanja

The threat of depletion of fossil fuels, extensively used in transport sector, is promoting the research in the field of alternative fuels. Biofuels possess properties close to that of diesel, but being viscous, used as blend with diesel in compression ignition (CI) engines. The current work explores the mixing of two biofuels, karanja oil and rice bran oil, in diesel (designated as RK20) and to observe the performance of CI engine. The blend was made by mixing the oils in the proportion of 10:10:80 (karanja oil, rice bran oil and neat diesel (ND), respectively). The test rig used to conduct the investigation was a double-cylinder, turbocharged and water-cooled direct injection CI engine having constant speed of 1800 rpm and fixed compression ratio of 18.5:1. The injection parameters were varied to optimize the performance parameters of CI engine for the prepared blend of biofuel. The optimized output parameters were brake specific fuel consumption (BSFC) and brake power (BP) of the CI engine. The ranges of injection timing (IT) and injection pressure (IP) were $${{15}\,^{\circ }}$$ – $${{28}^{\circ }}$$ btdc and 230–300 bar, respectively. Central composite design technique of response surface methodology was used for design of experiments. The results include the lowest BSFC at low IP and IT for both ND and RK20 blend, also comparable with each other. Maximum BP and minimum BSFC were predicted at $${{15}^{\circ }}$$ btdc and 230 bar IT and IP respectively for both RK20 blend and ND.

Performance and emission characteristics of waste frying oil biodiesel blends as pilot fuel on a dual fuel compression ignition engine

ABSTRACT In recent years, diesel engine researchers have turned onto alternative fuel due to international emission legislations and depletion of fossil fuels. Natural gas and biofuels as an alternative fuel have gained popularity with simple and low-cost utilization in diesel engines. In the present study, effect of compressed natural gas (CNG) application with pilot injection of waste frying oil biodiesel (WFOB) blends have been investigated on performance and emissions of a diesel engine running under full load at 3000 rpm speed. Engine tests have been carried out according to ISO 8178 E2 test cycle, at maximum rated power for 0%, 20%, 40%, and 60% substitution ratios of CNG and 0%, 10%, 20% of WFOB content in pilot diesel fuel. It is found that, in dual fuel mode; ignition delay period is longer than the standard diesel operation, and in dual fuel mode; thermal efficiency is lower than the standard diesel operation. Moreover, a significant reduction is observed in nitrogen oxides (NOx) emission and smoke opacity with an increase of carbon monoxide (CO) and hydrocarbon (HC) emissions. With the use of pilot WFOB blends, ignition delay period becomes shorter. NOx emissions increase, while CO, HC emissions, and smoke opacity decrease.

Emission Characteristic of a Dual fuel Compression Ignition Engine Operating on Diesel + Hydrogen & Diesel + HHO gas with same Energy Share at Idling Condition

Clean burning nature and renewability of hydrogen makes it viable and alternative / supplementary fuel for utilization in IC engine. In the past two decades, researchers have gained interest in using hydrogen in Internal combustion (IC) engines. Electrolysis is the widely used technique for production of hydrogen. The effect on emission parameters of using hydrogen and HHO gas in a dual fuel engine at idling condition was focused in this research work. HHO gas was synthesized from stored cylinders of hydrogen & oxygen in 2:1 ratio. The mixture of H2 and O2 are produced in stoichiometric ratio similar to electrolysis of water. Effect of introduction of hydrogen gas and stimulated HHO gas on emission characters such as unburnt hydrocarbon (UHC), carbon dioxide (CO2), oxides of nitrogen (NOx) and smoke of the engine were noted at idling condition (1700 rpm). Engine was supplied with 6, 12, 18, 24, 30, 36 LPM of hydrogen and 9, 18, 27, 36, 45, 54 LPM of HHO gas where the composition of mixture was maintained in the ratio of 2:1 and energy supplied by Hydrogen and HHO gas remains same. Introduction of hydrogen and HHO gas has reduced the total diesel fuel consumption and formation of CO2 at all operating condition than neat diesel operation. There was slight increase in UHC emission with hydrogen and by substituting HHO gas the UHC emission was reduced.

Effect of piston bowl geometry and compression ratio on in-cylinder combustion and engine performance in a gasoline direct-injection compression ignition engine under different injection conditions

Low temperature combustion (LTC) of high-octane number fuels in compression ignition engines offers an opportunity to simultaneously achieve high engine thermal efficiency and low emissions of NOx and particulate matter without using expensive after-treatment technologies. LTC engines are known to be sensitive to the operation conditions and combustor geometry. It is important to understand the fundamental flow and combustion physics in order to develop the technology further for commercial application. A joint numerical and experimental investigation was conducted in a heavy-duty compression ignition engine using a primary reference fuel with an octane number of 81 to investigate the effects of injection timing, piston geometry, and compression ratio (CR) on the fuel/air mixing and combustion covering different regimes of LTC engines, homogeneous charge compression ignition (HCCI), partially premixed combustion (PPC), and the transition regime from HCCI to PPC. The results show that with the same combustion timing, a higher CR leads to a lower NOx, but a higher emission of UHC and CO. The piston geometry shows a significant impact on the combustion and emission process in the transition regime while it has minor influence in the HCCI and PPC regimes. It is found that high engine efficiency and low emissions of NOx, CO and UHC can be achieved in the earlier PPC regime and later transition regime. The fundamental reason behind this is the stratification of the mixture in composition, temperature and reactivity, which is dictated by the interaction between the spray and the cylinder/piston walls.

An experimental investigation of the performance, emission and combustion stability of compression ignition engine powered by diesel and ammonia solution (NH4OH)

This study presents experimental examinations of a stationary single-cylinder compression ignition dual fuel engine for the combustion of diesel fuel with water ammonia solution. The effect of 25% water ammonia solution on the combustion, performance, emissions and stability of the dual fuel compression ignition engine was investigated, taking into account its different operating conditions. The experiments were carried out for three modes of engine operation with three loads (35%, 60% and 100%) and a change in the water ammonia solution energy fraction at 60% load, within the range from 0% to 17%. Co-combustion of diesel fuel with water ammonia solution in the test engine contributed to an increase in the ignition delay period and combustion duration, and to an increase in the heat release rate. Compared to the combustion of diesel fuel alone, combustion involving ammonia causes deterioration in the stability of the test engine operation, yet not exceeding the permissible stability indices for reciprocating combustion engines. Addition of water ammonia solution led to reduced nitrogen oxide emissions and increasing carbon monoxide and hydrocarbon emissions and did not result in significant changes in carbon dioxide emissions.

A comparative analysis of different methods to improve the performance of rubber seed oil fuelled compression ignition engine

There is a need to find suitable substitutes for the petroleum based fuels as the conventional fuels are decreasing in order in recent years. Vegetable oils are attractive as an alternative fuel for diesel engines as they are renewable and can be used in engines without employing any major modifications. The main problems with the use of neat vegetable oils in diesel engines are high smoke levels and relatively low thermal efficiency due to high viscosity and carbon residue as compared to diesel. In this work various methods for improving the performance of rubber seed oil (RSO) fuelled diesel engine are compared and discussed. Dual fuel operation with hydrogen, ethanol and DEE resulted in higher brake thermal efficiency. Oxides of nitrogen (NOx) level are lowest with neat RSO engine operation. It increases about 36% for dual fuel operation with hydrogen and 32% with DEE injection compared to neat RSO. Smoke emission reduces from 6.1 Bosch Smoke Unit (BSU) for neat RSO operation to 3.8 BSU for hydrogen induction, 4 BSU for DEE injection and 3.4 BSU for ethanol injection which is the lowest value compared to all other test fuels. Peak pressure and rate of pressure rise are higher for all the methods as compared to neat RSO operation. Ignition delay is higher for neat RSO operation; it further increases with dual fuel operation with hydrogen, LPG and ethanol. It is concluded that dual fuel operation with hydrogen and DEE is effective in improving the performance of neat rubber seed oil in compression ignition engine operation.

Autoignition of diethyl ether and a diethyl ether/ethanol blend

Binary blends of fast-reacting diethyl ether (DEE) and slow-reacting ethanol (EtOH) are quite promising as renewable replacements for conventional fuels in modern compression ignition engines. In this work, pure diethyl ether and a 50/50 M binary blend of diethyl ether and ethanol (DEE/EtOH) were investigated in a shock tube and a rapid compression machine. Ignition delay times were measured over the temperature range of 550–1000 K, pressures of 20–40 bar, and equivalence ratios of 0.5–1. Literature reaction mechanisms of diethyl ether and ethanol were combined to simulate the reactivity trends of the blends. Species rate-of-production and sensitivity analyses were performed to analyze the interplay between radicals originating from the two fuels. Multistage ignition behavior was observed in both experiments and simulations, with peculiar 3-stage ignition visible at fuel-lean conditions. Kinetic analyses were used to identify the reactions controlling various stages of ignition. Reactivity comparison of DEE/EtOH and dimethyl ether/ethanol (DME/EtOH) blends showed that the oxidation of DEE blends is controlled by acetaldehyde whereas formaldehyde controls the oxidation of DME blends.

Comparative analysis of waste vegetable oil versus transesterified waste vegetable oil in diesel blend as alternative fuels for compression ignition engine

The study presents a comparative evaluation of waste vegetable oil (WVO) versus transesterified waste vegetable oil (WVBD) in diesel blends for engine performance, emission characteristics, economics, and sustainability as an alternative fuel for a compression ignition engine. The impact of blend fraction and blend type on the fuel properties were determined. Increased WVO or WVBD fraction in the blend resulted in increased density, viscosity, flash points, and reduced calorific value. WVBD blends showed lower fuel consumption and better thermal efficiency performance, whereas other engine performance parameters were comparable to WVO blends. Emission characteristics of all the blends were comparable under all load conditions. Economic analysis showed that WVO blends are more cost-effective than WVBD blends. The sustainability analysis using the life cycle assessment methodology revealed lower environmental impacts were associated with WVO blends as compared to WVBD blends. The study pegs WVO blend as a more sustainable and economical diesel fuel alternative against the predominant and more explored WVBD blend.

Combustion improvement and pollutants reduction with diesel-gasoline blends by means of a highly tunable laser plasma induced ignition system

The use of alternative fuels in compression ignition engines, either completely or partially replacing the conventional ones, have potential to reduce pollutant emissions (especially soot). However, some of these fuels do not provide good ignition features under diesel engine like conditions, which affects engine efficiency. Thus, in order to extend the application of alternative fuels, the current research proposes the use of a laser induced plasma ignition system to assist on the combustion of blends of fuels with less reactivity than pure diesel. This fuel has been chosen as the base component and it has been mixed with gasoline (as the low-reactivity fuel) in different ratios as an example of fuels with very different reactivity properties. Tests have been performed in a single cylinder optically accessible engine, allowing deeper study of combustion development and soot formation. For different in-cylinder conditions and fuel blends, the effect of laser induced plasma ignition system has been evaluated at different crank angle degrees and locations inside the combustion chamber. The application of these blends under low-reactivity engine conditions show that combustion efficiency is dramatically affected. However, the study proves that it is possible to control blend ignition delay and flame lift-off length by means of laser induced plasma. Besides, using the proper ignition system configuration, combustion characteristics similar to those of diesel fuel autoignition can be achieved for high gasoline substitution rates. They lead to similar energy release rates, which confirms that diesel-gasoline blends can reach a combustion efficiency close to pure diesel, while a strong reduction on soot formation was also obtained. These results open a door to efficiency improvement and pollutant reduction by means of a highly tunable ignition of alternative fuel blends.

Investigation of Dual-Fuel Combustion by Different Port Injection Fuels (Neat Ethanol and E85) in a DE95 Diesel/Ethanol Blend Fueled Compression Ignition Engine

Abstract This paper investigated the effect of different substitution ratios of neat ethanol (E100) and ethanol–gasoline blend E85 on in-cylinder combustion, engine efficiency, and exhaust emissions, in a dual-fuel diesel engine, using the ethanol–diesel blend (DE95). Experimental studies realized at 1400 rpm, 1600 rpm, and 1800 rpm engine speeds under constant engine load of 50% (20 Nm). For each engine speed, the injection timing of diesel and E95 fuels at 24 °CA bTDC kept constant while low-reactivity fuels (i.e., E100 and E85) substitution ratio changed in the range of 59–83%. The results showed that premixed fuels in different SRs have an impact on shaping engine emissions, ignition delay (ID), in-cylinder pressure, and heat-release rate. Also, at the dual-fuel experimental studies in all engine speeds, NOx about 47–67% decrease compared to single fuel conditions of reference diesel and DE95, and smoke opacity remained unchanged around 0.1 FSN, whereas HC and CO increased in the range of 20–50%. However, E85/DE95 and E100/DE95 dual-fuel combustion achieved lower brake thermal efficiency (BTE) and combustion efficiency compared to single diesel fuel combustion. On the other hand, in dual-fuel combustion conditions, despite the low combustion efficiency, premixed E85 fuel offered higher engine efficiency and lower exhaust emissions than E100.

Emission Characteristics under Diesel and Biodiesel Fueled Compression Ignition Engine with Various Injector Holes and EGR Conditions

The combustion performance of a conventional rail diesel engine was investigated by measuring the exhaust gas with the respect to the number of injector holes, fuel type, and the use of exhaust gas recirculation (EGR), to provide a detailed reduction of environmental pollutants. It was found that a six- or seven-hole injector was more effective than a five-hole injector for reducing the exhaust gas. In addition, the mixing of 20% biodiesel oil with diesel most effectively reduced the HC and NOx contents. The technology generally reduced the NOx and CO contents of the exhaust, but had no significant effect on the HC and CO2 contents.

Effect of ceramic coating on the performance, emission, and combustion characteristics of ethanol DI diesel engine

Ethanol and vegetable oils played an important role for more than 70 years in many countries all over the world. Since 19th century, ethanol has been used as fuel for Compression Ignition (CI) engines. By fermenting and distilling the biomasses, ethanol can be obtained and hence it can be considered as a renewable fuel. One way of increasing the efficiency of the ethanol fuel CI engine is to use it as a Low Heat Rejection Engine (LHR). In LHR engine, the thermal efficiency of the CI engine can be increased by reducing the heat loss to the surroundings through coolant and exhaust gas. The heat can be transferred from the combustion chamber to the piston, cylinder wall and finally to the cooling water. The heat transfer can be minimized by insulating the piston and cylinder wall and coating the piston and the cylinder wall with ceramics, which can withstand high thermal stresses. The coating materials have low thermal conductivity, thus reducing the heat flux into the piston and thus the heat transfer to the coolant is reduced. In the present work, Zirconia is used for coating the engine components for lower thermal conductivity. It is concluded that sole ethanol as fuel with glow plug show a reduction in exhaust emissions with reduced efficiency compared with conventional CI engine operated with diesel fuel. But it was observed that, there is a slight increase in thermal efficiency of the engine with the retarded injection timing. Converting a conventional engine to low heat rejection diesel engine further increases the thermal efficiency and reduces the carbon monoxide and unburned hydrocarbon emissions drastically, whereas oxides of nitrogen emission are increased because of higher combustion temperature.

Investigation on 1-heptanol as an oxygenated additive with diesel fuel for compression-ignition engine applications: An approach in terms of energy, exergy, exergoeconomic, enviroeconomic, and sustainability analyses

Studies on alternative and environmentally friendly fuels for compression-ignition engines continue intensively. In this work, energy, exergy, exergoeconomic, enviroeconomic, and sustainability analyses have been conducted by evaluating performance and emission values obtained by operating with different ratios of 1-heptanol/diesel blends (Hp0, Hp5, Hp10, and Hp20) as novel fuels under a constant speed (1500 rpm) with different engine loads (25%, 50%, 75%, and full load) in a single-cylinder, four-stroke, water-cooled, direct-injection, compression-ignition engine. In the test engine, energy and exergy efficiencies and losses, energetic and exergetic powers, irreversibility, and destruction of the exergy for the aforementioned fuel blends have been calculated and compared with pure diesel fuel. In the tests, the highest fuel consumption was determined as 0.221 kg/kWh in HP20 fuel at 100% load because 1-heptanol has lower calorific value than that of neat diesel fuel. The energy efficiency values in different loads of diesel engine for all fuel blends (Hp0-Hp20) have been calculated to be as between 14.46% and 40.72% along with the corresponding exergy efficiency values have been found to be as between 13.43% and 37.79%. By performing emission measurements, the highest CO2 emission cost has been calculated as 66.94 USD/year at a 100% load in Hp10 fuel according to the enviroeconomic analysis. In this present research, by implementing the exergoeconomic analysis, the highest engine output power cost at a load of 25% has been noted to be at 1.6 USD/MJ for Hp20 blend. Sustainability analysis has been determined according to the SI index, and the highest index was calculated to be 1.6 at a 100% load for Hp0 fuel.

OMEx-diesel blends as high reactivity fuel for ultra-low NOx and soot emissions in the dual-mode dual-fuel combustion strategy

Previous works demonstrated that the use of Oxymethylene ether (OMEx) in advanced combustion modes, as the dual-mode dual-fuel combustion, leads to a notable reduction of the lifecycle CO2 emissions while promoting lower NOx and soot emissions than those from conventional diesel combustion. Nonetheless, the low heating value of OMEx results in a fuel consumption increase. A possible solution to avoid this drawback is by blending OMEx with diesel fuel. This will help to introduce the OMEx in the market with minimum changes in the infrastructure. In this context, this work evaluates the impact of using OMEx-diesel blends in different mass percentages (50% and 70% of OMEx in diesel), compared to the reference net fuels (net diesel and OMEx) in a multi-cylinder compression ignition engine operating under dual-mode dual-fuel combustion at different engine loads (25%, 50%, 80% and 100%) and 1800 rpm. At each condition, an air mass sweep was performed to assess the limiting operating conditions with each fuel due to either excessive pressure gradients and soot production, or low combustion efficiency. The results suggested that the OMEx-diesel blends allow to reduce the soot emissions compared to net diesel for all the conditions tested. In addition, blends having an OMEx mass content greater than 70% allowed to fulfill the EUVI limits for NOx with ultra-low soot levels (<0.01 g/kWh) up to 80% engine load. Nonetheless, the unique fuel able to achieve the EUVI limit for NOx with zero soot emissions simultaneously at 100% of engine load was found to be the pure OMEx.

Effect of air preheating, exhaust gas re-circulation and hydrogen enrichment on biodiesel/methane dual fuel engine

An experimental study was carried out to investigate the effect of intake air pre-heating, exhaust gas re-circulation, and hydrogen enrichment on performance, combustion, and emission characteristics of CH4/waste cooking oil biodiesel fuelled compression ignition engine in dual fuel mode. Methyl ester derived from waste cooking oil was used as a pilot fuel which was directly injected into the combustion chamber at the end of the compression stroke. The CH4/hydrogen-enriched methane was injected as the main fuel in the intake port during the suction stroke using a low pressure electronic port fuel injector which is controlled by an electronic control unit. The experiments were conducted at a constant speed and at the maximum load. Experimental results indicated that the increase in energy share of gaseous fuel extends the ignition delay. With air preheating the thermal efficiency increased to 49% and 55% of CH4 and hydrogen-enriched CH4 energy share, respectively. The CO and HC emissions were higher in CH4 combustion with biodiesel when compared to the conventional diesel operation at full load and a reduction in CO and HC was observed with air preheating. Lower NOx were observed with gaseous fuel combustion and it further reduced with exhaust gas re-circulation but NOx increased by preheating the intake air. Improvement in thermal efficiency with a reduction in HC and CO was observed with hydrogen-enriched CH4.

국내 경유 대체연료로써 커피박 바이오오일 혼합연료의 압축착화엔진 적용성에 관한 연구

국내 경유 대체연료로써 커피박 바이오오일 혼합연료의 압축착화엔진 적용성에 관한 연구

Numerical study on the performance of a homogeneous charge compression ignition engine fueled with different blends of biodiesel

The increasing need for fossil fuels along with their limited resources and also environmental concerns caused by pollution from internal combustion engines have always led researchers to improve the technology. The use of homogeneous compression ignition combustion technology as well as alternative fuel sources such as biodiesel is proposed as a novel and promising solution to achieve goals including improving efficiency and reducing environmental pollutants specifically NOx and CO2 that are emerging in the industry. In this study, the effect of using different blends of diesel/biodiesel fuel on thermal performance along with output pollution of a homogeneous fuel compression ignition engine is investigated. The fuels range from B00 to B40, and parameters such as engine thermal efficiency, maximum cylinder pressure and exhaust emissions have been evaluated. The results show retarded and reduced maximum pressure with a decrease in engine thermal efficiency, a reduction in NOx and CO2 emissions and an increase in CO emissions, while the mass fraction of biodiesel in the fuel composition is increased. Moreover, in the investigated engine, the B20 is considered as the optimum composition with a reduction of 4.2% in maximum cylinder pressure, 5% in thermal efficiency and 26% in NOx emissions compared to B00.

Oxygenated Fuels in Compression Ignition Engines

Oxygenated Fuels in Compression Ignition Engines