Performance Of Compression Ignition Engine Research Articles

Experimental study on ammonia-diesel co-combustion in a dual-fuel compression ignition engine

Ammonia, as a carbon-free renewable fuel and a potential hydrogen carrier, is gaining increasing interest in addressing greenhouse gas emissions in industrial applications and transportation. This paper presents experimental studies on the co-combustion of ammonia with diesel fuel in a single-cylinder industrial compression ignition engine operating in dual-fuel mode. The energy share of ammonia ranged from 0 to 60%. Increasing the proportion of ammonia compared to diesel fuel in the compression ignition engine leads to a change in the combustion process character, increasing the kinetic combustion phase at the expense of diffusive combustion. However, it does not result in an increase in the peak pressure rise (PPR) beyond the permissible value of 1 MPa/deg for piston engines. It increases ignition delay and shortens the combustion duration, while also increasing thermal efficiency and decreasing specific energy consumption. An increase in the NH3 share results in a decrease in combustion efficiency, a reduction in unit emissions of NO, CO2, and soot, and an increase in CO emissions. Beyond 42% ammonia share, it reduces unit THC emissions. At a 42% ammonia share, the dual-fuel engine achieves the highest indicated thermal efficiency (ITE), lowest specific energy consumption (SEC), shortest combustion duration, and lowest unit soot emissions.

Biodiesel production from spent coffee grounds utilizing pomegranate/orange peel biochar as a green and renewable nanocatalyst: Compression ignition engine performance and emission

In this research, a novel pomegranate/orange peel-derived activated carbon (POPAC) green heterogeneous nanocatalyst was developed for the conversion of spent coffee grounds oil (SCGO) into biodiesel by ultrasonication and its application in diesel engine characteristics. The surface and texture attributes of the POPAC green nanocatalyst were scrutinized employing SEM, EDX, CO2-TPD, XRD, TEM, FTIR, Raman, and BET. Based on the response surface methodology (RSM) outcomes, the highest biodiesel efficiency employing POPAC green nanocatalysts was 95.24 %, which was attained at optimal conditions (i.e., molar proportion of 11.02, nanocatalyst content of 2.56 wt%, ultrasonic time of 30.77 min, and temperature of 60 0C). Moreover, the stability assessment demonstrated the high reusability of POPAC green nanocatalysts, with biodiesel efficiency remaining at 87.43 % even after the 7th round. Further, the kinetic survey exhibited that the biodiesel synthesis is endothermic and the conversion rate is enhanced by boosting the temperature. Besides, the impact of merging biodiesel with the diesel/biodiesel combination at diverse torques was scrutinized on the emission of exhaust output (e.g., UHC, NOx, CO, and CO2) and engine crucial characteristics (i.e., BP, EGT, BTE, and BSFC), and encouraging results were acquired. Briefly, due to special attributes including high catalytic performance, substantial recyclability, and eco-friendliness, POPAC green nanocatalyst are highly suggested for biodiesel generation.

Investigation of the use of aluminum oxide nanoparticle-enhanced waste cooking oil blends in compression ignition engines.

The sustainable utilization of waste cooking oil (WCO) as an alternative to fossil fuels has gained considerable attention due to its potential for delivering substantial environmental and economic benefits. This research attempts to explore the impact of incorporating aluminum oxide nanoparticles (AONP) into WCO on the emissions, combustion characteristics, and overall performance of a single-cylinder compression ignition (CI) engine. Comparative analyses were conducted against conventional commercial diesel fuel and pure WCO, as well as varying blends of WCO with AONP at 25ppm, 50ppm, and 75ppm concentrations. The experimental results demonstrate a notable enhancement in brake thermal efficiency (BTE), with a 13.2% increase observed in the WCO + 75 AONP fuel blend compared to neat WCO. Engines fueled by WCO nanoparticle blends showed significant augmentation in-cylinder pressure and heat release rates. Furthermore, these blends exhibited a substantial reduction in carbon monoxide (CO), hydrocarbons (HC), and soot emissions by 44%, 31%, and 48%, respectively, while nitrogen oxide (NO) emissions increased by 7% compared to neat WCO. Among the assessed fuel mixtures, the WCO + 75 AONP blend demonstrated higher engine performance. This study underscores the potential of aluminum oxide nanoparticle-enhanced WCO blends as viable and environmentally responsible options for sustainable energy solutions. However, challenges such as production costs and long-term fuel stability must be addressed to establish nano-fuels as financially viable alternatives.

Control of combustion distributions in compression-ignition engines using rate-constrained model predictive control with reference preview

To support the transition toward sustainable alternative fuels, advanced combustion control strategies can enable operation of compression-ignition engines with a wide range of fuels under challenging inlet conditions. This work presents a rate-constrained model predictive controller that uses state estimate feedback and integral tracking to control combustion phasing distributions by coordinating fuel injection timing with the power supplied to an electrically heated in-cylinder ignition assist device. The controller was validated in simulation using a statistical virtual engine that replicates both transient and steady-state stochastic combustion behavior. This virtual engine was tuned with data from experiments conducted at a low pressure-temperature inlet condition that induced highly variable combustion behavior akin to operating with a low cetane fuel. The controller achieves rapid tracking of combustion phasing step commands by supplying ignition assist power when needed to support fuel injection timing. All the while, it maintains closed-loop combustion variability at less than 6% higher than the open-loop system variability, and enforces ignition assist power range and rate constraints to reduce thermo-mechanical stress on the actuator. Furthermore, reference tracking is ensured even if combustion sensitivity to the ignition assist actuator deviates by as much as 83% from the controller’s internal model, without the need for retuning control parameters. Finally, the controller can coordinate actuators early and speed up tracking when a reference trajectory is previewed ahead of time, and its horizons can be tuned in a manner that maintains desirable control performance without compromising on computational tractability.

Effects of operating parameters on start performance of compression ignition engine by using high-pressure direct-injection pure methanol fuel

Methanol was one of the research hotspots in internal combustion engines over recent years. The application of methanol is a promising approach to transport decarbonization due to low carbon content. However, the utilization of methanol in compression ignition (CI) engines faces some challenges as a result of low reactivity and high latent heat of vaporization, such as cold start and operation stability. Furthermore, the impact mechanisms of operating parameters on cold start and operation stability in CI engine have not been understood deeply. In this work, the effects of operating parameters on average cycle of start and coefficient of speed variation (CoVspeed) of idle were studied on a CI engine fueled by pure methanol fuel. Results show that the injection strategy of the minimum average starting cycle number is the pre-main injection, which includes lower injection pressure, −4 °CA ATDC (degree crank angle after top dead center) main timing, smaller pre mass, and larger pre-main interval. The injection strategy of the minimum CoVspeed of idle is the pilot-pre-main injection, which includes lower injection pressure, −4 °CA ATDC main timing, smaller pre mass, larger pre-main interval, smaller pilot mass, and shorter pilot-main interval. Under the same operating conditions, the average cycle of start is 12 and 5 for methanol and diesel respectively. The CoVspeed of idle is 6.72% and 0.53% for methanol and diesel respectively. When coolant temperature is 30 °C, the minimum intake temperature is 120 °C. Upon adjusting the coolant temperature to 80 °C, the minimum intake temperature decreases to 80 °C.

Blending action of pyrolysis oil/diesel fuel featured with hydrogen on compression ignition engine performance and emission analysis

Waste high-density polyethylene (HDPE) is a non-biodegradable toxic, and harmful material. To maintain environmental sustainability, the waste HDPE involves alternative fuel extraction. The main objective of this study is to extract the alternative oil fuel from the source of the waste HDPE through pyrolysis with a reactor temperature of 300–550 °C and study the compression ignition (CI) engine performance and emission behavior. ASTM standards evaluate the physical and chemical properties of oil fuel, and its results showed that 40 and 43 °C flash and fire point temperatures, better Cetane number of 49, and a good calorific value of 43.17 MJ/kg. The CI engine performance and its emission behavior are experimentally studied with different blending ratios of HDPE oil: hydrogen: diesel fuel like 0:0:100 (D), 0:5:95 (5HD), and 10:5:85 (10B5HD). With this output, results of 10B5HD exhibited better engine performance like better brake power (BP–6.78 kW), optimum brake specific fuel consumption (BSFC-0.52 kg/kWh), improved brake thermal efficiency (BTE-28.78%) and reduced emission behavior including carbon monoxide (CO-0.43%) and carbon dioxide (CO2-24 ppm), hydrocarbon (HC-5.4%) and nitrogen oxide (NOx-760 ppm). Based on these results, 10B5HD performed better than diesel fuel and was utilized in future alternative fuel applications.

Performance and CO2 emission of a single cylinder compression ignition engine powered by Khaya senegalensis non-edible seeds fuel blends

This work aimed at investigating blends of Khaya senegalensis biodiesel in a compression ignition engine, attempting to improve engine performance and reduce CO2 emission compared with conventional diesel. Analysis of System (ANSYS) was used to predict in-cylinder behavior of the fuel. ANSYS SpaceClaim generated the geometric model on which 5° sector and mesh refinement was on ANSYS Internal Combustion Engine Modeler (ICEM). Computational domain of interest lies within the compression and expansion strokes. Experimental validation followed: 5% biodiesel, 95% diesel (B5); 15% biodiesel, 85% diesel (B15); 25% biodiesel, 75% diesel (B25); pure diesel (D100); pure biodiesel (B100) in volume proportions. B15 has the highest brake mean effective pressure (BMEP) of 4 bar as load increases. An experimental and numerical comparison reveals pressure declination against speed increment. Ignition temperature fluctuated between 799.76 and 806.256 K for D100 and 760.73–790.62 K for B100 within 1800–2800 rpm speed limit prediction. Power and brake thermal efficiency (BTE) had parallel load increment with all blends. CO2 emission on increasing load conditions were 47.01%, 8.07%, 21.72% and 6.06% for B5, B15, B25, and B100 respectively lower than D100. Pressure and temperature contours gave proper combustion predicted behaviors. All blends possess replaceable performance potential for D100 however, B5 offers better reliable potentials.

Performance and emission analysis of hydrogen-fuelled compression ignition engine with EGR: a prospective approach towards clean mobility

The energy demand has still been fulfilled, primarily by fossil fuels globally. Hydrogen is the only carbonless fuel that can fulfil the energy demand without impacting the environment. In this research work, a variable compression ratio (VCR) CI engine with exhaust gas recirculation (EGR) is tested with hydrogen gas as a primary fuel. Initially, the diesel is used as a pilot fuel igniter to initiate the combustion process. Once the cycle is initiated, the hydrogen gas is supplied and controlled through port fuel injection at a pressure of 2 bar. The engine is operated at various compression ratios (12, 14, 16, 18) and different loads: 0% (0 kg), 25% (4 kg), 50% (8 kg), 75% (12 kg) and full load (16 kg), with and without exhaust gas recirculation. The results revealed that the brake thermal efficiency of the hydrogen-fuelled engine increased by 6.5% and a significant decrement in brake-specific fuel consumption (bsfc). The maximum cylinder pressure inside the cylinder is observed at 68 bar at 12 kg of load and 18 CR. The NOx emission is reduced by 49.4% by using the cold ERG method.

Computational investigation of equivalence ratio effects on performance and emissions in a dual-fuel homogeneous charge compression ignition (HCCI) engine with 90% n-dodecane and 10% ethanol

As the automotive industry seeks environmentally friendly and fuel-efficient solutions, a significant transformation towards the Dual Fuel Homogeneous Charge Compression Ignition (DF-HCCI) Engine. It emerges as a highly promising and revolutionary approach to internal combustion engines. This paper provides a comprehensive Computational Investigation on the influence of Equivalence Ratio (ϕ) variations on the performance and emissions of a DF-HCCI engine, utilising a blend of 90% n-dodecane (premix) and 10% ethanol (spry injection). Through simulations, the study explores ϕ ranging from 0.45 to 0.70, providing a detailed analysis of their impact on crucial engine parameters. Results indicate a non-monotonic behaviour in piston work, with an initial increase followed by a decline beyond an optimal point due to incomplete combustion. CO emissions exhibit a general increase with higher ϕ, attributed to reduced air availability for complete combustion. CO2 emissions display a non-monotonic trend, peaking at ϕ = 0.5, indicative of a complex interplay between combustion temperature and completeness. NOx emissions decrease with rising ϕ, as higher temperatures favour NOx formation. Soot emissions decrease with increasing ϕ , correlating with lower combustion temperatures. This investigation provides insights into the relationship between ϕ and DF-HCCI engine characteristics, offering an optimising engine efficiency and mitigating environmental impact.

Using renewable alternative fuels and studying their impact on the performance and emissions of compression ignition engines

AbstractThis practical study examined the effect of engine torque on engine performance and emissions. The most important parameters of engine performance are thermal efficiency, brake power (BP), and specific fuel consumption. As for exhaust emissions, the most important of which are hydrocarbons (HCs), carbon monoxide (CO), and nitrogen oxides (NOx). The experiment was conducted for a single‐cylinder, four‐stroke compression ignition engine. Mixtures (B0, B10, B20, B30, and B40) were taken from biodiesel prepared from sunflower oil by the esterification method. The engine speed was fixed at 1700 rpm, and torque variable was from 0 to 10 N m. The results indicated a decrease in engine BP by an average of 19.5 W, a decrease in thermal efficiency by an average of 1.058%, while an increase in fuel consumption by an average of 0.095 kg/kW h−1 compared to diesel. As for exhaust emissions, HC emissions decreased by 5.8 ppm, while CO decreased by 0.0207%, and NOx emissions increased by 138.5 ppm compared to diesel, due to changes in the properties of biodiesel, such as high density, viscosity, and low calorific value compared to the properties of regular diesel

Optimizing compression ignition engine performance and emissions with onboard oxygen concentrator: an experimental study

Optimizing compression ignition engine performance and emissions with onboard oxygen concentrator: an experimental study

Effect of fuel injection pressure on the performances of a CI engine using water-emulsified diesel (WED) as a fuel

BackgroundThe choice of energy sources is essential for sustainable development to combat different environmental issues caused by the consumption of fossil fuels. Though diesel engines are considered more efficient and reliable than other internal combustion engines, they emit different harmful pollutants which are detrimental to human health and the environment. Researchers are trying to find suitable alternative fuels for diesel engines with lower pollutant emissions and without much compromise in the efficiency of the engine. In this regard, water-emulsified diesel (WED) may be considered to be one of the most suitable alternative fuels. It is expected that the entire world will use electric vehicles in the long term. However, the complete replacement of IC engines in the near future is not feasible. In fact, different European countries have targeted to ban the use of diesel engine cars before the middle of the twenty-first century. Prior to that date, hybrid vehicles will be more popular and diesel engines will continue to play an important role. Hence, research involving improvements in diesel-operated IC engines is still relevant.MethodsAn experimental investigation was carried out using WED containing 10% water by volume as a fuel in a diesel engine at four different fuel injection pressures. The WED was prepared using an ultrasonicator.ResultsWith the increase of injection pressure, peak net heat release rate and in-cylinder pressure are found to have increased. Brake thermal efficiency is also found to have improved at higher injection pressure. The maximum efficiency was recorded when a WED at 210 bar of injection pressure is used, and it is about 3.3% higher than the maximum efficiency achieved when using normal diesel at the same pressure of fuel injection. At a higher load, neat brake-specific fuel consumption is found to be less compared to neat diesel, when only the amount of diesel contained in the emulsion as a fuel is considered. Maximum reduction in both NOx and smoke emission by using WED is recorded at 210 bar, and the average reductions are determined to be 32.6% and 51.9%, respectively.ConclusionsWED can be used as an alternative fuel for existing diesel engines without any retrofitting and with significant reduction in the emissions of pollutants compared to normal diesel fuel. It can also be concluded that at higher injection pressure, the combustion, performance and emission characteristics of compression ignition engines are improved when using emulsified diesel.

Optimization and modeling of the performance of compression ignition engine fired on biofuel from non-edible vegetable oils

Compression ignition CI engine are versatile engines required for both industrial and domestic purposes. CI finds application in household mill, transportation and as components in energy plants. Operating the CI engine with biodiesel and its combination with fossil-based diesel is being encouraged to combat environmental menace of using only fossil diesel. This current work seeks to probe into comparison between the use of biodiesel and its emulsion to improve the performance CI engine. Methyl esters was synthesized from blends of three nonedible oils; Tevetia Peruviana, Honne and Neem (THN) using catalyst made from three bio wastes mixture. The production process was optimized using Taguchi tool. The THN methyl esters (THNME) obtained was assessed for fuel properties. Box Behnken tool was adopted to generate 17 investigational steps to explore the effect of THNME 100 and parts containing 20% and 60% of THNME on the fuel efficiency and safety of the CI engine. These fuel mixes were used as fuel in an unmodified single cylinder CI engine. The engine was operated on three engine loads (EL) 25%, 50% and 75% as well as engine speeds (ES) 1500, 2500 and 3500 rpm (rpm). The result obtained showed that blend of THNME with fossil diesel has the minimum exhaust gas temperature EGT. ANOVA of the performance result shows that the model developed is suitable to predict the behaviour of brake power and exhaust gas temperature only. This work conclude that B20 is moderately fuel efficient and safer for the unmodified engine in terms of EGT and BSFC.Novelty: Emulsion of THNME B20 is a preferred fuel for the safety of the unmodified CI engine because of low EGT

The Effect of Different Mixing Proportions and Different Operating Conditions of Biodiesel Blended Fuel on Emissions and Performance of Compression Ignition Engines

Faced with the depletion of fossil fuels and increasingly serious environmental pollution, finding an environmentally friendly renewable alternative fuel has become one of the current research focuses. In order to find new alternative fuels, reduce dependence on fossil fuels, improve air quality, and promote sustainable development goals, castor biodiesel was produced through transesterification, and mixed with diesel in a certain proportion. The engine performance and emissions were compared and analyzed under fixed load and different speeds of agricultural diesel engines. Biofuel, as a fuel containing oxygen, promotes complete combustion to a certain extent. As the proportion of castor biodiesel in the mixed fuel increases, the emissions of pollutants such as CO, HC, and smoke show a decreasing trend. The lowest CO, HC, and smoke emissions were observed in the B80 blend at 1800 rpm, at 0.3%, 23 ppm, and 3%, respectively. On the contrary, the CO2 and NOx emissions of the B80 blend are higher than those of 2.7 diesel, reaching 2.5% and 332 ppm respectively at 1800 rpm. The lower calorific value and higher viscosity of biodiesel result in a decrease in BTE and an increase in the BSFC of the blends. Higher combustion temperatures at high speeds promote oxidation reactions, resulting in reduced HC, CO, and smoke emissions, but increased CO2 and NOx emissions. At high speeds, fuel consumption increases, BSFC increases, and BTE decreases. Overall, castor biodiesel has similar physical and chemical properties to diesel and can be mixed with diesel in a certain proportion for use in CI engines, making it an excellent alternative fuel.

Effect of Fuel Injection Strategies on Performance, Regulated and Unregulated Emissions of a Gasoline Compression Ignition Engine

Abstract Gasoline compression ignition (GCI) mode engines are characterized by partially premixed charge combustion, leading to significant and simultaneous reductions of nitrogen oxides and particulate matter emissions. However, gasoline compression ignition engine operation suffers from a limited operating window. Air preheating and low-research octane number fuels are required to improve the engine performance. This experimental study used a blend of 70% (v/v) gasoline and 30% diesel as test fuel in a direct injection medium-duty compression ignition engine. Experiments were carried out at 5- and 10-bar brake mean effective pressure (BMEP) engine loads at 1500–2500 rpm engine speeds using a triple injection strategy (two pilots and one main injection) for all test conditions. The combustion phasing was kept constant with respect to crank angle to produce a high power output. The investigations examined engine performance and regulated and unregulated emissions. The test engine was initially operated in conventional diesel combustion mode with diesel for baseline data generation. Gasoline compression ignition mode operation demonstrated a remarkable 16% increase in the brake thermal efficiency and a substantial reduction of 65% in nitrogen oxide emissions compared to the baseline conventional diesel combustion mode. The GCI engine exhaust showed higher concentrations of regulated emissions, namely hydrocarbons and carbon monoxide, and unregulated trace emissions, such as methane, acetylene, toluene, inorganic gaseous species, and unsaturated hydrocarbons.

Modeling hydrogen–diesel dual direct injection combustion with FGM and transported PDF

This work extends the transported probability density function (PDF) method to model hydrogen–diesel dual direct injection (H2DDI) combustion, where a H2 jet is ignited by a small pilot diesel jet flame. The work is motivated by previous H2DDI engine tests where stable compression ignition engine operation was reported with up to 90 % H2 supply by energy share. To help explain this high performance and provide a tool to help further engine optimization, the Eulerian Monte Carlo Fields (EMCF) solution method is employed with which a transported PDF equation is solved in combination with Flamelet Generated Manifold (FGM) for high accuracy and computational efficiency. In all cases, the pilot fuel ignites before interacting with the H2 jet and thus reaction rate and chemical composition are computed as the weighted average of the corresponding values taken for two separated FGM tables generated for the two fuels. Pressure measurements and high-speed schlieren imaging performed in a preburn-type optical constant volume combustion chamber (CVCC) with n-heptane (nC7H16) pilot fuel were used to validate the EMCF+FGM model. The application focus is how H2 ignition and combustion is affected when the nC7H16 is injected prior to or after the main H2 jet. EMCF+FGM computed heat release rate and flame structure were compared with experimental data and results from conventional FGM model based on presumed PDF. When applied to H2DDI combustion, the EMCF+FGM model successfully reproduces flame structures and heat release rate under different injection strategies, including the transition towards partially-premixed combustion when the nC7H16 pilot follows the main H2 injection. Moreover, analysis of heat release rate from different stochastic fields can provide a useful indication about cyclic variability and combustion stability.

Synergistic effects of nano-enhanced waste transformer oil and hydrogen premixing on CI engine performance and emissions

Waste materials possess untapped potential when harnessed effectively. One such resource is waste transformer oil, derived from electrical transformers, which can be converted into a valuable fuel source for compression-ignition (CI) engines using pyrolysis techniques. In this study, we explored the utilization of a 50 % blend of waste transformer oil with diesel, augmented with Titanium dioxide nanoparticles (referred to as “nano fuel of waste transformer oil”), in an unmodified CI engine. To further enhance the performance of this nano fuel, we introduced hydrogen (at flow rates of 2.5 LPM, 5.0 LPM, and 7.5 LPM) into the inlet section during the suction phase, promoting premixing within the cylinder. Hydrogen premixing significantly improved combustion dynamics. Notably, when 7.5 LPM of hydrogen was introduced alongside waste transformer oil-derived nano fuel, a remarkable 37.30 % increase in brake thermal efficiency was achieved. Moreover, this configuration exhibited a 15.33 % reduction in brake-specific fuel consumption (BSFC), a 27.09 % decrease in carbon monoxide (CO) emissions, a 37.50 % decrease in unburned hydrocarbon (UHC) emissions, and a 28.53 % reduction in smoke opacity compared to traditional diesel operation. These results highlight the potential for enhanced CI engine performance and reduced emissions through the strategic combination of waste transformer oil-based nano-fuel and hydrogen premixing. Consequently, we recommend further exploration of hydrogen premixing in conjunction with nano-enhanced waste transformer oil for superior CI engine performance.

Experimental study on combustion, performance, and emission characteristics of a homogeneous charge compression ignition engine fuelled with multiple biofuel-gasoline blends

For sustainable future mobility and power generation applications, there is a compelling need to develop flex-fuel engines that operate with multiple regional or season-specific biofuels. The present investigation focussed on mitigating agricultural diesel engines’ pollutant emission and performance problems. A systematic experimental study is carried out in a modified agricultural diesel engine to compare and evaluate the engine characteristics of the biofuel-gasoline blends fuelled Homogeneous Charge Compression Ignition (HCCI) mode. Seven different oxygenated biofuels: acetone, ethanol, methanol, isopropanol, isobutanol, ethyl acetate, and diisopropyl ether blended in gasoline, were investigated. 2-Ethylhexyl nitrate was used to improve the reactivity of fuel blends to the extent that lower engine loads could be reached. All the investigated biofuel-gasoline blends could produce permissible emission levels by suitably tuning the fuel proportions. The total nitrogen oxides and smoke emissions were below 2.8 and 0.0007 g/kWh, respectively, for all the investigated biofuel-gasoline blends at all the HCCI engine load conditions. The highest indicated thermal efficiency of 42% was attained using 60% ethanol/34% gasoline/6% 2-EHN blend in the HCCI engine at 4.63 bar BMEP (86% rated load), a notable 25% improvement compared to the conventional diesel engine. A detailed investigation was done to elucidate the HCCI engine performance (indicated thermal efficiency) trend variations with biofuel type and engine load. The Response Surface Method was adopted to correlate the maximum and the minimum engine load with the fuel composition and properties. The Desirability Approach provided the optimum fuel composition and properties to maximize the engine load range. The optimum solution achieved the engine load range of 20%–89% rated load. Overall, a compact, efficient, and clean HCCI combustion-based engine technology was developed that could be operated using multiple biofuels over an expanded load range.

Comparative evaluation of different operating parameters on performance, combustion, and emission characteristics in gasoline compression ignition (GCI) engine by using carbon neutrally biofuels

The stringent emission regulations and energy shortage put forward strict requirements for highly efficient and clean combustion for internal combustion engines. The gasoline compression ignition (GCI), which is a new advanced combustion concept, can obtain high efficiency and low emissions simultaneously without many modifications of standard diesel engines. However, little research has been carried out to synergistically optimize the operation parameters in a wide load range, especially fueled with the carbon neutrally biofuels. Therefore, in this paper, the effects of various operating parameters on engine performance, combustion, and emission characteristics of the gasoline compression ignition (GCI) strategy fueled with a blend of butanol and biodiesel were investigated. Specifically, the impact of butanol energy ratio, fuel direct injection timing, and exhaust gas recirculation (EGR) at the indicated mean effective pressure (IMEP) of 4, 8, and 14 bar and the butanol energy ratio of 60%, 70%, and 80% were examined. Result shown that the increase in butanol energy ratio decreased the fuel reactivity and worsen the combustion process, while the lower butanol energy was also disadvantage to the engine performance. The indicated thermal efficiency could achieve 48.5% when the butanol energy ratio was 70% at medium engine load. The earlier fuel injection timing was needed at low engine load, the EGR was necessary to inhibit the in-cylinder pressure rise at high engine load, in which the EGR rates of 20% at the IMEP of 8 bar and 30% at the IMEP of 14 bar could achieve the optimum engine performance, respectively. Meanwhile, the nitrogen oxides emissions shown a greatly decrease with the EGR rates increase, and it was less than 200 ppm at the IMEP of 14 bar when the EGR rates were 50%.

Experimental study of the effect of structural differences in the composition of kerosene-like blended fuels on low-temperature autoignition in a constant volume combustion chamber

The cold start performance of compression ignition engines at high altitudes is expected to be improved by means of fuel design involving kerosene-like blended fuels. In this study, the autoignition characteristics of ten blended fuels with different chemical compositions and physical properties were investigated in a constant volume combustion chamber. Steady-state conditions in a low thermal atmosphere are considered at varying temperatures (723, 773, 823 K), pressures (2.2, 2.8, 4 MPa), injection pressures (40, 60, 80 MPa), and injection pulse widths (1.5, 2.5, 5 ms). The relative importance and relevance of the physical and chemical properties of the fuel to the ignition delay were evaluated based on characteristic parameters e.g. total ignition delay, physical delay, chemical delay, combustion delay, pressure and heat release rate evolution. It was found that adding ether-oxygenated component content to kerosene-like significantly shortened the ignition delay, followed by chain alkanes, naphthenes, and aromatics, in that order. The effect of oxidation chemistry changes on the ignition performance of fuels in low-temperature-pressure environments is more significant than physical properties. As the thermal atmosphere or fuel activity intensifies, the percentage of physical delay in the total ignition delay gradually exceeds that of chemical delay as the main part, and the variability in the ignition qualities of fuels with different physicochemical properties diminishes. There is a good linear correlation between ignition delay and cetane number (ranging from 44 to 60), density, viscosity, and recovery temperature, whilst the role of cetane number and density is more prominent.