Increasing Engine Load Research Articles

NOx emission reduction through selective catalytic reduction using copper-based Y zeolite catalyst: experimental investigation and characterization

Growing concerns surrounding global warming and environmental degradation have prompted the widespread adoption of various emission control methodologies, with a particular emphasis on reducing nitrogen oxide (NOx) emissions. Selective catalytic reduction (SCR) stands out as a highly effective technique, applicable not only to large-scale industrial machinery but also to smaller vehicles, aimed at converting NOx emissions into less harmful nitrogen (N2) using specialized catalysts and reductants. This particular study focuses on synthesizing copper-based Y zeolite and conducting experiments using ethanol as a reductant in the exhaust stream of a two-cylinder diesel engine operating under different loads. Furthermore, the catalyst was subjected to thorough characterization using techniques such as Scanning Electron Microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS), X-ray Diffraction (XRD), and Brunauer-Emmet-Teller (BET) analysis. Results indicate that as temperature and engine load increase, the efficiency of NOx conversion also improves. The highest conversion rate, reaching 94.67%, was achieved at 260°C under a 5 kW load. Additionally, average conversion rates of 90%, 90.70%, and 92.62% were observed for loads of 1 kW, 3 kW, and 5 kW, respectively. These findings not only highlight the effectiveness of SCR technology in reducing NOx emissions but also underscore the potential of copper-based Y zeolite catalysts in this regard. The comprehensive characterization of the catalyst provides valuable insights into its structural and chemical properties, paving the way for further advancements in emission control strategies.

Identification of the Problem in Controlling the Air–Fuel Mixture Ratio (Lambda Coefficient λ) in Small Spark-Ignition Engines for Positive Pressure Ventilators

The air–fuel ratio is a crucial parameter in internal combustion engines that affects optimal engine performance, emissions, fuel efficiency, engine durability, power, and efficiency. Positive pressure ventilators (PPVs) create specific operating conditions for drive units, characterized by a reduced ambient pressure compared to standard atmospheric pressure, which is used to control carburetor-based fuel supply systems. The impact of these conditions was investigated for four commonly used PPVs (with internal combustion engines) in fire services across the European Union (EU), using a lambda (λ), carbon dioxide (CO2), carbon monoxide (CO), and hydrogen carbon (HC) analyser for exhaust gases. All four ventilators were found to operate with lean and very lean mixtures, with their lambda coefficients ranging from 1.6 to 2.2. The conducted tests of the CO2, CO, and HC concentrations in the exhaust gases of all four fans show dependencies consistent with theoretical analyses of the impact of the fuel–air mixture on emissions. It can be observed that as the amount of burned air decreases, the values of CO and HC decrease, while the concentration of CO2 increases with the increase in engine load. Such an operation can accelerate engine wear, increase the emission of harmful exhaust gases, and reduce the effective performance of the device. This condition is attributed to an inadequate design process, where drive units are typically designed to operate within atmospheric pressure conditions, as is common for these engines. However, when operating with a PPV, the fan’s rotor induces significant air movement, leading to a reduction in ambient pressure on the intake side where the engine is located, thereby disrupting its proper operation.

Assessing Particulate Emissions of Novel Synthetic Fuels and Fossil Fuels under Different Operating Conditions of a Marine Engine and the Impact of a Closed-Loop Scrubber

Particle emissions from marine activities next to gaseous emissions have attracted increasing attention in recent years, whether in the form of black carbon for its contribution to global warming or as fine particulate matter posing a threat to human health. Coastal areas are particularly affected by this. Hence, there is a great need for shipping to explore alternative fuels that both reduce greenhouse gas emissions, as anticipated through IMO, and also have the potential to reduce particle emissions significantly. This paper presents a comparative study of the particulate emissions of two novel synthetic/biofuels (GTL and HVO), which might, in part, substitute traditionally used distillate liquid fuels (e.g., MDO). HFO particulate emissions, in combination with an EGCS, formed the baseline. The main emphasis was laid on particle concentration (PN) and particulate matter (PM) emissions, combining gravimetric and particle number measurements. Measurements were conducted on a 0.72 MW research engine at different loads (25%, 50%, and 75%). The results show that novel fuels produce slightly fewer emissions than diesel fuel. Results also exhibit a clear trend that particle formation decreases as engine load increases. The EGCS only moderately reduces particle emissions for all complaint fuels, which is related to the formation of very fine particles, especially at high engine loads.

Ammonia fueled engine with diesel pilot ignition: Approach to achieve ultra-high ammonia substitution

Ammonia is a hydrogen-rich zero-carbon fuel, and is one of the most promising approaches to realize energy decarbonization in the fields of industry and transportation. Efficient operation and emissions control have been the primary obstacle to develop engines with high ammonia energy share. In this study, the combustion and emissions of an ammonia-fueled engine with diesel pilot ignition are investigated, and the target is to achieve ultra-high ammonia substitution with acceptable thermal efficiency. The ammonia energy share is first increased from 30% to 90% at an intermediate load, with a split diesel injection triggering ammonia combustion. It found that the increased ammonia energy share reduces the indicated thermal efficiency from 48.3% to 38.9% with high unburned ammonia emissions. The NOx emissions exhibit a turning point with increased ammonia substitution, which indicates that the NOx emissions transition from the thermal-dominated to the fuel-dominated regime. The diesel pilot injection strategy is then optimized, by advancing the main injection timing and changing the pre-injection amount and the interval between two injection events. Optimized diesel injection controls the ignition timing and combustion process, thereby improving thermal efficiency and emissions at high ammonia energy shares. An ultra-high ammonia energy share of 95% could be finally achieved, and the thermal efficiency is 40.2%. It is also noted that as engine load increases, engine thermal efficiency at an ammonia energy share of 80% could be elevated to 44.2%.

Experimental study on reducing BC emissions from a low-speed marine engine by using blended biodiesel and a nitro additive

The aim of this study was to evaluate the emission reduction effect of using waste oil biodiesel/diesel binary fuel and a nitro additive on black carbon (BC) emissions from a large marine engine fueled by heavy fuel oil (HFO). We conducted steady-state conditions tests on a low-speed two-stroke marine engine, where pure distillate diesel (D100), blended biodiesel (blending ratios of 10%, 30%, and 50%), low-sulfur heavy fuel oil (LSFO), high-sulfur heavy fuel oil (HSFO), and a nitro additive were tested, and the BC emission concentrations from the engine were measured under different conditions using a filter-type smoke meter (FSM) and a photoacoustic smoke meter (PAS). The results indicated that BC emissions from the engine were significantly decreased when blended biodiesels were used, with the decline rate increasing as the engine load increased, reaching a maximum reduction of 73% and 94% under 75% and 100% load compared to the use of HFOs, respectively. However, the use of biodiesel slightly increased the brake specific fuel consumption (BSFC) and NOx emissions. The nitro additive was blended with LSFO and HSFO at a ratio of 1:1200, respectively. It was observed that the introduction of the nitro additive led to a significant reduction in BC emissions compared to the use of pure HFOs. But different from the case of using blended biodiesels, the decline rate of BC decreased with increasing engine load. The BC emissions from LSFO and HSFO were decreased by approximately 10% and 25% under 25% load, respectively, the corresponding BSFC decreased by 5.88% and 3.71%, respectively, while the NOx emissions increased by 11.59% and 34.58%, respectively. In addition, the BC emissions measured by the FSM were on average 38.56% and 43.53% higher than those of the PAS when LSFO and HSFO were used, respectively.

Effect of Biodiesel blending on emissions and efficiency in a stationary diesel engine

This paper presents an investigation into the effect of biodiesel blending on emissions and efficiency in a non road diesel engine. Rapeseed based biodiesel blended in increments of 25% with fossil diesel. The emissions of CO2 show a decrease in emission (g/kWh) with increased engine load. Within the range of tests carried out, the NOx emissions from biodiesel and its blends proved to be higher than those of petro-diesel fuel. Furthermore, in this study a correlation was found relating the NOx emissions and the flame temperature. The efficiency of the system is improved with increased biodiesel content in the fuel. As predicted the results for CHP show a considerable improvement to the overall efficiency.

Engine-out emissions from an ammonia/diesel dual-fuel engine – The characteristics of nitro-compounds and GHG emissions

In the transportation sector, ammonia used as a power source plays a significant role in the scenario of carbon neutralization. However, the engine-out emissions correlations of ammonia-diesel dual-fuel (DF) engines are still not totally clear, especially the nitro-compounds of great concern and GHG. In this study, the engine-out emissions are evaluated by using a four-cylinder pilot diesel-ignited ammonia DF engine. Various operating conditions consisting of ammonia energy ratio (AER), engine load, and speed were carried out. Unburned NH3 increases with raising ammonia content but decreases with increasing engine load and speed. The NO + NO2 tendency shows a non-linearity trend with increasing ammonia content, while a trade-off correlation is linked to N2O. The 20 % and 70 % decarbonization targets need 40 % and 80 % ammonia energy without regard to N2O’s effect, while at least 60 % and 90 % ammonia energy respectively with considering N2O. N2O presents a parabolic-like tendency with AERs. Advanced pilot-diesel injection timing helps to reduce both NH3 and N2O, but this effect becomes insignificant as the AER is less than 0.4. A combustion optimization strategy of the rapid heat release and ammonia-governed heat release respectively are revealed. The possible emission improvements are discussed in detail.

Efficiency optimization of a vehicle combustion engine by the adjustment of the spark advance angle

Changing the ignition advance angle has a significant impact on the performance of a combustion engine. Optimization of ignition advance angle is a major task of adjusting engine concerning emission standards, fuel consumption, torque value, etc. The results of the research showed that the process of optimizing ignition advance curve can noticeably increase engine efficiency, as well as torque and power output from the engine, while reducing fuel consumption as a result of lower indications of the air flow mass per second from MAF sensor (mass air flow sensor). The highest impact of the ignition advanced angle modifications can be seen in the area of the highest volumetric efficiency of the tested combustion engine. Almost no impact is observed within high engine speed levels. Simultaneously increasing engine load and rotation speed increases the possibility of engine knocking, which has devastating effect on engine durability.

Comparative analysis of waste tire pyrolysis oil and gasoline as low reactivity fuel in RCCI engine

ABSTRACT The utilization of alternative fuels in internal combustion engines has gained significant attention due to concerns about energy security and environmental sustainability. Waste tire pyrolysis oil (WTPO) is a potential alternative fuel that can be produced from waste vehicle tires through a pyrolysis process. In this study, the possible use of WTPO in a diesel engine operating under Reactivity Controlled Compression Ignition (RCCI) mode was investigated. In the study, the use of WTPO as a low-reactivity fuel in RCCI engines is examined, highlighting the importance of innovative approaches to alternative fuels with varying reactivity levels for effective combustion control and emission reduction. In the experimental work, WTPO was tested at different energy rates of 15%, 30%, and 45% into the intake port using the PFI system, while conventional diesel fuel was injected directly into the cylinder by the CRDI system. The tests were carried out under different engine load conditions while maintaining a constant engine speed of 2400 rpm. The performance, combustion, and emission characteristics of the engine were analyzed and compared between WTPO and conventional gasoline fuel as LRF. The study results show that using WTPO in RCCI operation with sustainable ringing intensity leads to significant increases in Brake Thermal Efficiency (BTE) compared to gasoline usage, with BTE increments of up to 5%, 3.3%, and 6.3% observed with increasing engine load. Furthermore, WTPO usage in RCCI engines effectively reduced hydrocarbon (HC) emissions, addressing a significant issue, and maintaining the known benefits of reactivity-controlled combustion. These findings suggest that WTPO can be utilized as a viable low-reactivity fuel in RCCI engines with acceptable performance, combustion, and emission characteristics.

The effects of metallic fuel addition into canola oil biodiesel on combustion, engine performance and exhaust emissions

In the current study, canola oil biodiesel was produced with transesterification method. Biodiesel was added to the neat diesel at the rate of 20% (B20). 50 ppm, 100 ppm and 150 ppm nanoparticles (Quantum Dots) were added to B20. The influences of fuels on combustion, performance and emissions were researched in a single-cylinder diesel engine. Engine experiments were performed at 2200 rpm and engine loads including 4.12, 9.61, 15.10 and 20.60 Nm. It was found that the difference in cylinder pressure between diesel and blended fuels decreased with the increase of engine load. Igntion delay (ID) was shortened with the addition of metallic fuel. Specific fuel consumption (SFC) decreased by 3.08%, 8.70% and 17.69% using D80TCB20C50, D80TCB20C100 and D80TCB20C150 compared to D80TCB20 at 15.10 Nm. Thermal efficiency increased by 83.74%, 89.09% and 89.30% using D80TCB20C50, D80TCB20C100 and D80TCB20C150 compared to D80TCB20 at 15.10 Nm. The lowest maximum pressure rise rate and ringing intensity were determined with neat diesel. HC reduced by about 1.75%, 5.26% and 7.01% D80TCB20C50, D80TCB20C100 and D80TCB20C150 compared to neat diesel at 20.60 Nm. Remarkable reduction was also observed on soot emissions. Soot emissions reduced 83.11%, 85.45% and 86.36% 1.75%, 5.26% and 7.01% D80TCB20C50, D80TCB20C100 and D80TCB20C150 compared to neat diesel at 20.60 Nm. On the other hand, NOx and CO emissions increased with the addition of nanoparticle.

The effects of combustion phasing induced by water injection on deNOx performance of GDI engine at MBT ignition timing

The call for greenhouse gas emission reduction as the result of global warming has been the main cause of the more rigorous emission legislation in the road transportation sector. In response to such requirements, car makers opt for the ‘down-sizing’ trend for engine displacement with the aim to increase brake thermal efficiency by increasing engine load (mean effective pressure). However, this leads to higher potential of engine knocking and elevated NOx emissions. This study investigates the effects of combustion phasing induced by water injection via the intake manifold of a naturally aspirated GDI engine at MBT ignition timing fuelled with E20. Water up to 30% of fuel mass is port-injected during high engine load and maximum NOx reduction of up to 82% could be achieved as the result of lower RoHR caused by vaporisation of water. Water injection prolonged the ignition delay and combustion duration (CA1090) without deterioration of combustion stability (%COV of IMEP). The optimisation of ignition timing based on MBT can improve CO emission compared to EGR systems. The proposed study demonstrates the possibility to achieve low nitrogen emissions without the need of precious metal-based catalysts.

Hydrogen production from an on-board reformer for a natural gas engine: A thermodynamics study

In the present study, for an insight into the optimizing windows of comprehensive energy efficiency for open-loop system of marine NG engine and reformer, a peculiar thermodynamic equilibrium model for simulating the exhaust gas-fuel reforming process is established using equilibrium constant and experimental results. The accuracy of the model is evaluated by comparing numerical simulations with data derived from experiment of the open-loop operation system. Accordingly, the effect of engine loads and excess air (λ) as well as reformer feedstocks on maximum theoretical reforming characteristics are investigated. In addition, the energetic distribution in open-loop operation system can be clarified by the first law of thermodynamic. The results shown that fuel conversion toward H2 is highly selective due to the enhancement of reaction temperature with increasing engine loads. Especially, under 75% engine load, the maximum theoretical H2 yield reaches up to approximately 42.3% when λ = 1.4, CH4/O2 (M/O) = 1.5 and H2O/CH4 (S/M) = 2; The high λ will dilute the feed concentration of the reformer, thereby inhibiting the reforming reaction moving toward H2 production. Hence, an appropriate λ (1.4) can maximize the hydrogen production capacity of the reformer. In addition, according to the energy distribution of the open-loop system, the theoretical reforming energy efficiency of the reformer reaches a peak of 93.5% at S/M = 2 and M/O = 5. However, it can be found that M/O should be maintained above 1.5 to acquire optimal reforming energy utilization efficiency of system. Summarily, the optimal operation conditions for the reformer in open-loop operation system are confirmed: M/O = 1.5–2.5 and S/M = 1.5–2 under 75% engine load, which could fulfill efficient reforming performance.

Study on gasdynamic interaction in a regulated two-stage turbocharging turbines at pulsating conditions

Understanding the response of performance of two-stage turbine to pulsating flow in exhaust manifold system is essential for performance improvement of engine. This paper studies unsteady interaction of two turbines in a two-stage turbocharging system via experimental method and a reduced order model. Firstly, experimental results of the unsteady pressure ratio of two turbines are discussed in cases with different engine speeds, engine loads, and bypass valve openings. Results show that the pressure ratio distribution between two turbines is profoundly influenced by the engine condition. The pressure ratio of low-pressure turbine (LPT) increases consistently with the engine speed and load, while it increases slightly or even remains unchanged for high-pressure turbine (HPT). HPT is de-loaded when the bypass valve is open, and there are large numbers of fluctuations with high frequencies in the trace of pressure ratio when the bypass valve is open. Next, a reduced order model of the two-stage turbine is established for turbine responses at pulsating conditions, and model validations of performance and unsteady pressure in two-stage turbine all show high precision. Finally, the model is applied for performance analysis of two-stage turbine system under pulsating conditions. The results show that with the increase in engine speed, load or bypass valve opening, the hysteresis loops of both turbines are expanded around the steady performance curve. However, the deviation of cycle-average performance from steady case for two turbines is notably different. LPT shows a stronger throttling effect at pulsating inflows. Moreover, compared with steady performance for whole two-stage turbine, cycle-average performance is reduced for all pulsating cases, especially for cases of open valve. The differences in turbine performance of two-stage turbine system caused by gasdynamic coupling effect of two turbines are suggested to be considered in the turbo-engine matching.

Experimental investigation into the effects of Argemone biodiesel/diesel blends on cyclic variations in a multi-cylinder CRDI engine

Abstract Internal combustion engines suffer from high cyclic variations that result in higher emissions, lower efficiency, higher fuel consumption and poor drivability. The purpose of this study is to investigate how Argemone mexicana biodiesel (AGB)/diesel blended fuels affect the cyclic variability of combustion parameters such as maximum cylinder pressure (Pmax) and indicated mean effective pressure (IMEP) in a four-cylinder turbocharged intercooled common-rail direct injection engine under various engine loading conditions. The chemical and physical properties of AGB produced from A. mexicana oil were measured and compared according to the ASTM D6751 standards. In various volumetric ratios, AGB and diesel fuel were blended as D100, AB10 (10% AGB + 90% D100), AB20 (20% AGB + 80% D100) and AB30 (30% AGB + 70% D100). The IMEP and Pmax time-series data were collected over 200 consecutive cycles at low, partial and high engine loads at a constant engine speed of 2000 rpm. The coefficients of variation (COV) of combustion parameters (Pmax and IMEP) were measured for different AGB/diesel blends and found to be within acceptable limits. The results show that COVPmax and COVIMEP decrease as the engine load increases. It was observed that at low load, AB10 has the lowest COV (Pmax, IMEP), and at partial and high load, AB20 has the lowest COV (Pmax, IMEP) among all the blends.

Research on the usability of various oxygenated fuel additives in a spark-ignition engine considering thermodynamic and economic analyses

In this study, thermodynamic and economic analyses of binary fuel blends (E15, EA15, M15, MA15, and T15) using commercial gasoline as fuel and oxygenated fuel additives (ethanol, ethyl acetate, methanol, methyl acetate, and terpineol) at 15% by volume in a spark-ignition engine were performed. Performance and emission tests were carried out at various engine loads at a constant speed of 1500 rpm using commercial gasoline and five different fuel blends. Thermodynamic analyses were carried out on the test data. The augmentation in engine load caused an increase in exergy losses and a decrease in the unit cost of engine power exergy values. Specifically for gasoline fuel, the unit cost of engine power exergy at 25% engine load is 1.99 times higher than at 100% load. In fuel blends, the pump price of each fuel affects the fuel cost rate. Exergy efficiency in fuel blends increases with increasing engine load. The highest exergy efficiency is 19.58% for gasoline fuel at 100% engine load. It is 15.95% for M15 fuel at the same load. The exergy values of G100 and T15 fuel were closest to each other and T15 offered better energetic and exergetic performance than the other binary blends.

Experimental Investigation of Oil Transport during Low Load to High Load Transient in Internal Combustion Engines

Reducing the Lubricating Oil Consumption (LOC) has been a critical focus for engine manufacturers. LOC not only depends on engine operating condition but also the history of the operating condition variations. This work seeks to understand the oil transport in the ring pack during the low load to high load transient through experimental investigations. An optical engine with 2D Laser Induced Fluorescence (2D-LIF) technique, equipped with a modern low-tension Three-Piece Oil Control Ring (TPOCR), was applied to investigate the oil transport in the ring pack. It was found that, after the engine stayed under the blowby separation line long enough, a sudden increase to high load can result in a huge increase of oil ejection to the liner from the top ring groove in the expansion strokes. The mechanism behind it is that, when the load is increased, the oil accumulated inside the top ring groove during the low load condition is pushed out by the gas flow after the peak cylinder pressure is reached. Different combinations of load, speed, rate of change in load and time duration at low load were tested to examine their influence on this leakage mechanism. An operation with a gradual increase of engine load was found to be able to reduce the amount of oil leaked to the liner by releasing more oil to the second land. These findings can help the effort to reduce the oil emission (OE) generated from Spark Ignited (SI) engines equipped with TPOCR in the real-world transient driving conditions as well as the emission tests.

Particulate emissions and soot characterisation of diesel engine exhaust for steady-state operating condition using dioctyl phthalate blends with diesel

The study investigates the particulate emission and soot characterisation of particles originating from a six-cylinder common-rail direct injection (CRDI), turbocharged diesel engine. The experiments were conducted using steady-state operating conditions, a constant rpm of 1500 and four different engine loads (25, 50, 75, and 100%). Three different fuels were tested: neat diesel and two dioctyl phthalate (DOP) blends with diesel (DOP10 and DOP20). Particulate emissions were measured using DMS500 and collected on transmission electron microscope (TEM) grids for further analysis of the morphology and nanostructure of the soot structure. The particle number and mass concentrations for neat diesel were found to be lower than DOP fuel blends for all four loads. The primary particle diameter increases with increase in the engine load and decreases with an increase in DOP fuel content in the blend. A compact structure of soot aggregate was observed for DOP fuel blends compared to that of diesel and it increased with an increase in the engine load. Short and curved fringes were observed for DOP fuel blends. Also, an increase in fringe length and a reduction in fringe tortuosity was observed with an increase in engine load. The fringe separation distance results show an opposite trend with respect to fringe length and fringe tortuosity for DOP fuel blends i.e. less inter-planar spacing was observed for DOP fuel blends compared to that of diesel. This would result in an overall decrease in the oxidation reactivity of soot particles.

Effects of Engine Load and Ternary Mixture on Combustion and Emissions from a Diesel Engine Using Later Injection Timing

As a high oxygenated fuel, bioethanol has already obtained more and more widespread attention in diesel engines. The present work aims to study and compare effects of various diesel-bioethanol-biodiesel ternary mixture fuels on combustion and emissions from a four-cylinder diesel engine. A series of engine experiments are conducted on neat diesel fuel (D100), 95% D100 blended with 5% bioethanol and 1% biodiesel by volume (D95E5B1), 90% D100 blended with 10% bioethanol and 1% biodiesel by volume (D90E10B1), and 85% D100 blended with 15% bioethanol and 1% biodiesel by volume (D85E15B1) according to various engine loads (40, 80 and 120 Nm). The experimental results show that the peak value of pressure and heat release rate (HRR) in the cylinder, nitrogen oxides (NOx) and smoke emissions increase with the increase in engine load, but the brake specific fuel consumption (BSFC) decreases. There is no significant variation in cylinder pressure with the addition of ethanol, but HRR is improved and NOx and smoke emissions are effectively controlled. It is exciting that the addition of ethanol can simultaneously reduce NOx and smoke emissions under medium and high load conditions. Specifically, at 120 Nm, ethanol addition simultaneously reduces NOx emissions by 2.08% and smoke opacity by 36.08% on average. Through the results of this study, it is found that the ethanol can improve the combustion of the four-cylinder diesel engine and also effectively control the emissions of NOx and smoke. Therefore, ethanol will play an important role in the future research field of energy saving and emission reduction for diesel engines.

Evaluation of the use of diesel-biodiesel-hexanol fuel blends in diesel engines with exergy analysis and sustainability index

The present research examined the usability of diesel-biodiesel and diesel-biodiesel-hexanol fuel blends as an alternative to diesel fuel in a compression ignition engine. Energy and exergy analyses were conducted using the data obtained from the engine tests. In addition, the sustainability index was calculated. When selecting the most suitable fuel for diesel fuel, thermal and exergy efficiency and sustainability index values ​​were compared. The obtained results revealed that the most suitable alternative fuel for diesel fuel was the diesel-biodiesel binary fuel blend. In this fuel blend, thermal efficiency, exergy efficiency, and sustainability index values ​​are 3.8, 5.18, and 1.44 % higher, respectively, compared to pure diesel fuel at an engine load of 100 %. As the alcohol ratio increases in diesel-biodiesel-hexanol ternary blends, the sustainability index value decreases compared to diesel fuel. As the hexanol ratio increases in fuel blends, the sustainability index decreases. The highest sustainability index for ternary fuel blends is 1.26 at 100 % engine load in B45H10 fuel. The increase in engine load increases the sustainability index and exergy efficiency in all fuel blends.

Experimental investigation of the control strategy of high load extension under iso-butanol/biodiesel dual-fuel intelligent charge compression ignition (ICCI) mode

Advanced combustion modes have shown the great advantages to achieve high thermal efficiency and low pollution emissions. However, lack of sufficiently control over combustion phasing of heat release under high and ultra-high engine load limits the commercial application. In this paper, an experimental investigation had been conducted to explore the control strategy under iso-butanol/biodiesel dual-fuel intelligent charge compression ignition (ICCI) mode for achieving the high engine load extension. The criteria is used to identify clean combustion under high load expansion, which the indicated thermal efficiency is 45% or higher, and nitrogen oxides (NOx) emissions should be below 400 ppm. The results show that stable and controllable ICCI operation is obtained under high and ultra-high engine load. An iso-butanol single direct injection in the intake stroke, biodiesel double direct injection strategy in the compression stroke and near top dead center, respectively, offers a very competitive pathway to expand the engine load with clean and highly efficient combustion, in which the maximum indicated thermal efficiency reaches 49.9% and NOx emissions below 100 ppm at the indicated mean effective pressure (IMEP) of 12 bar, and the maximum engine load reaches 18 bar IMEP (96% engine load). At higher engine load, lower iso-butanol energy ratio is used to reduce the in-cylinder pressure and maximum pressure rise rate, while punishes the engine thermal efficiency and emissions. With the iso-butanol energy ratio increase, the lower in-cylinder reactivity leads to the increase of incomplete combustion products. In addition, the exhaust gas recirculation (EGR) is essential on the reduction of NOx emissions, and the second biodiesel injection duration is increased with the engine load increase for the purpose of the load expansion.