Methanol Engine Research Articles

Combustion characteristics of methanol engine applying TJI-HPDI with optimized pre-chamber nozzle structure under different injection and spark strategy

Methanol fuel faces challenges in achieving mixing controlled combustion (MCC) due to its low cetane number. This study proposes utilizing turbulent jet ignition to facilitate methanol MCC under high-pressure direct injection mode, namely TJI-HPDI. Three coordination schemes were developed numerically based on the projection angles between hot jets and main methanol spray plumes axis: opposing (Base design), opposing staggered (Design 1), and circumferential staggered interference (Design 2). Varied orifice diameters was employed to regulate jet energy and velocity. The results indicated that Design 2-BSB (Big-Small-Big orifice) scheme exhibited superior combustion and emission performance. Furthermore, the impact of start of main injection timing (SOI) on ignition and combustion characteristics was investigated under this scheme. An SOI of -12 °CA after top dead center (TDC), creating a 7 °CA interval between spark and SOI timing, achieved optimal ITE by minimizing the duration of CA10-CA50 and optimization methanol mixture distribution around hot jets. Additionally, pre-chamber (PC) spark ignition timing (ST) effects were also explored, with the optimal timing at -8 °CA ATDC. ST has minimal impact on heat release rate (HRR), because high-energy jets could ensure rapid and stable combustion. Moreover, the combustion stability of TJI-HPDI was demonstrated, underscoring the importance in understanding and optimizing TJI-HPDI ignition processes.

A Study of Heat Recovery and Hydrogen Generation Systems for Methanol Engines

Biofuels are the most essential types of alternative fuels, which currently have significant potential to reduce CO2 emissions compared to fossil fuels. Methanol is a more efficient fuel than petrol due to its physicochemical properties, such as a higher latent heat of vaporization, research octane number, and heat of combustion of the fuel–air mixture. Also, biomethanol is cheaper than traditional petrol and diesel fuel for agricultural countries. The authors have proposed a new approach to improve the characteristics and efficiency of methanol diesel engines by using biomethanol mixed with hydrogen instead of pure biomethanol. Using a hydrogen–biomethanol mixture in modern engines is an effective method because hydrogen is a carbon-free, low-ignition, highest-flame-rate, high-octane fuel. A small quantity of hydrogen added to biomethanol and its combustion in an engine with a heat exchanger increases the combustion temperature and heat release, increases engine power, and reduces fuel consumption. This article presents experimental results of methanol combustion and a hydrogen-in-methanol mixture if hydrogen was retained due to the utilization of the heat of the exhaust gases. The tests were carried on a single-cylinder experimental engine with an injection of liquid methanol and gaseous hydrogen mixtures. The experiments showed that green hydrogen generated onboard the car due to the utilization of heat significantly reduced fuel costs of engines of vehicles and technological installations. It was established a hydrogen gaseous mixture addition of up to 5% by mass to methanol requires a corresponding change in the coefficient of excess air to λ = 1.25. Also, using an additional hydrogen mixture requires adjustment at the ignition moment in the direction of its decrease by 4–5 degrees of the engine crankshaft. Hydrogen gas mixture addition reduced methanol consumption, reaching a maximum reduction of 24%. The maximum increase in power was 30.5% based on experimental data. The reduction in the specified fuel consumption, obtained after experimental tests of the methanol research engine on the stand, can be implemented on the vehicle engines and technological installations equipped with an onboard heat recovery system. Such a system, due to the utilization of heat and the supply of additional hydrogen, can be implemented for engines that work on any alternative or traditional fuels.

Hydrogen enrichment in methanol SI engine at varying injection timing during compression stroke

This study investigates the effect of hydrogen enrichment in a direct-injected methanol-fuelled SI engine, with combustion and emission performance analysed by varying the methanol injection timing from 150° to 60° CA bTDC. A three-dimensional computational fluid dynamic model of the hydrogen-enriched methanol engine was developed to predict the engine performance, in-cylinder, and emission characteristics. The numerical model was solved using three-dimensional Reynolds-Averaged Navier Stokes, the RNG k-epsilon model for turbulence, the O'Rourke and Amsden sub-model for heat transfer, the extended Zeldovich mechanism for nitric oxide emissions, and the Hiroyasu-NSC model for soot emissions. The results indicated that retarding the injection timing resulted in a decrease in the indicated specific CO and soot emissions along with a rise in the indicated specific NOx emissions. Furthermore, hydrogen enrichment with methanol enhanced the hydroxyl radical concentration, reduced the combustion duration, reduced also the indicated specific CO and soot emissions while increasing the indicated specific NOx emissions. The study indicates that hydrogen enrichment could extend the late injection timing limit of methanol by enhancing fuel-air mixing, which improves and controls the combustion process more effectively.

Energy analysis during cold start and warm up period of a methanol engine hybrid power system under several novel energy conversion strategies

The use of methanol in engine hybrid power system has a wide range of potential applications, with the primary challenge being cold start issues. This paper innovatively proposes four strategies for starting and warming up the methanol engine, including motor dragging, motor dragging coupled with exhaust gas recirculation (EGR), motor dragging coupled with exhaust control, and motor dragging coupled with both EGR and exhaust control. These strategies can be implemented in methanol hybrid power system with minimal hardware modification costs, and not generate any emissions compared to traditional gasoline assisted strategy. The warm-up mechanisms of these strategies were analyzed and their effectiveness was verified by experiments. The optimum strategy, motor dragging coupling both EGR and exhaust control, has been demonstrated to enhance power input and improve the energy conversion efficiency substantially. Compared to the traditional gasoline assisted strategy, the energy consumption, energy conversion efficiency and the warm-up time in this strategy are 17.9 % lower, 5.1 % higher, 4.2 s shorter, respectively. These strategies well solve the problem of methanol engines being unable to start at low temperatures, which is expected to eliminate the cold start of the engine and directly enter the hot start.

Self‐Thermostatic Internal Combustion Engine—Proton Exchange Membrane Fuel Cell Hybrid Power Generation System Based on Methanol

Traditional internal combustion engines (ICEs) have garnered considerable attention due to their high emissions and low efficiency issues. In this study, a novel ICE–fuel cell hybrid power system based on a single‐methanol fuel is proposed to address these concerns. The system utilizes methanol as fuel, directly supplying it to the methanol engine, and generates hydrogen for the fuel cell through methanol reforming technology. The structural design of the system fully exploits engine exhaust, first using waste heat for methanol reforming to produce hydrogen and then utilizing exhaust inertial potential energy to drive a dual turbocharging structure for air compression entering the fuel cell, thereby achieving self‐thermal balance. Thermodynamic analysis and cost evaluation indicate that the thermal efficiency of this system is improved by 8.34% compared to traditional diesel engine setups. Compared to engine‐fuel cell hybrid systems that do not utilize waste heat, the thermal efficiency is increased by 5.81%. In terms of economics, the cost of the methanol engine system is ≈.1466$ , which is 44.05% lower than the 0.262 $ fuel cost of traditional diesel engine systems. This study presents an innovative solution that significantly enhances thermal efficiency and offers economic advantages, providing a viable approach to address the low efficiency and high emissions issues of traditional ICEs.

Thermodynamic performance analysis of direct methanol solid oxide fuel cell hybrid power system for ship application

Methanol is a fuel that can be directly supplied to solid oxide fuel cell (SOFC) without carbon deposition. This paper introduces the direct methanol SOFC-Internal combustion engine (ICE) hybrid power and SOFC-Gas turbine (GT) hybrid power systems. Thermodynamic performance analysis of the hybrid power systems and an investigation into the impact of various parameters were conducted. The results indicate that the electric efficiency of the SOFC-ICE system is 56.07 %, which is 3 percentage points higher than the SOFC-GT system but 3–4 percentage points lower than the SOFC-ICE system with pre-reforming. Increasing fuel utilization rate, operation temperature, and excess air ratio is beneficial to the performance of the SOFC, and raising current density helps improve the system's power density. Load-sharing strategy research demonstrates that in a scenario where the power ratio between SOFC and the ICE is 35:65, compared to a methanol engine, the efficiency of the SOFC-ICE hybrid power system increases by 4.3 %. Despite a 1.4-fold increase in weight and a 1.66-fold increase in cost, the fuel consumption rate and carbon emissions decrease by 8.8 %. Therefore, the strategy of combining a high-power engine with a low-power SOFC is currently a suitable load-sharing strategy for ship applications.

Simulation Analysis of a Methanol Fueled Marine Engine for the Ship Decarbonization Assessment

Methanol as marine fuel represents one of the most cost-effective and practical solutions towards low-carbon shipping. Methanol fueled internal combustion engines have a high level of technological readiness and are already available on the market; however, technical data in terms of fuel consumption and emissions are not yet easily accessible. For this reason, the present study deals with the simulation of a virtual spark-ignition methanol engine, carried out in a Matlab-Simulink© R2023a environment to assess the CO2 emissions in several working conditions of a possible ship power system. The thermodynamic model of the methanol fueled engine is derived from a marine gas engine simulator, already validated by the authors in a previous work. This article presents the relevant modifications necessary to adapt the engine to the methanol fuel mode with regard to the different fuel characteristics. The simulation analysis compares the results of the virtual methanol engine with available data from a similar, existing gas engine, highlighting the differences in efficiency and carbon dioxide emissions.

Investigation on efficient and clean combustion pre-injection strategy of a diesel/methanol dual direct-injection marine engine under full load

Diesel ignition in-cylinder direct-injection methanol marine engine has shown enormous application potential due to its superior fuel economy and lower carbon emission. However, with high vaporization latent heat in methanol and increasingly strict emission regulations, new injection strategy urgently need to be studied to further improve the engine performance. To explore the feasibility of achieving high-efficiency and low-emission combustion by using pre-injection strategy in a diesel/methanol dual direct-injection marine engine, a numerical investigation is conducted to understand the combustion development, the mechanism of forming unregulated emissions, and the influence of methanol pre-injection timing (SOMIpre) and methanol pre-injection ratio (MPR) on engine performance. The results reveal that too early SOMIpre leads to a wet wall, while too late SOMIpre leads to insufficient mixing, thereby deteriorating combustion stability. The optimal fuel economy characterizing an indicated thermal efficiency (ITE) of 49.58% can be achieved when methanol is pre-injected at 35° crank angle (CA) before the top dead center (BTDC). As SOMIpre advances, the peak in-cylinder pressure (Pmax), peak heat release rate (HRRmax), and indicated mean effective pressure (IMEP) are decreased, along with increased soot, CO, and HC emissions, while the emissions of NOX and CO2 remain essentially unchanged. Additionally, the optimal methanol pre-injection strategy is yielded with an SOMIpre of 35°CA BTDC and an MPR of 15% when adopting a diesel injection timing (SODI) of 20°CA BTDC, increasing ITE by 19.9% and 2.7% and cutting CO2 emissions by 19.4% and 2.9% compared to the prototype (pure-diesel mode) and single-injection strategy. The results of this study provide new direction and data support for the research and development of efficient and clean combustion marine methanol engines.

Calibrating the Livengood–Wu integral knock model for differently sized methanol engines

Experimental test campaigns have begun to demonstrate the potential of methanol as an alternative fuel for heavy-duty spark-ignited engines. However, there is no consensus yet on the scope of this solution in terms of maximum power and engine size. A zero-dimensional combustion model is therefore being developed outside the scope of this work. Its main objective will be to predict key performance parameters such as power and efficiency as function of engine size. Due to the high loads typically encountered in heavy-duty engines, knock will be the main constraint to maximize the engine's potential. This work therefore aims to find an accurate knock model that can be implemented in the modelling framework. The Livengood–Wu knock integral model is being considered as a good candidate, as it is computationally inexpensive and thus allows for a large number of engine configurations to be modelled within a reasonable time. Due to a lack of autoignition delay times of methanol at conditions relevant to heavy-duty engines, a large database was created using chemical kinetics calculations. A neural network model was trained with the tabulated data for fast data retrieval. To validate whether the knock integral approach is robust enough to be applied to a wide range of engine sizes, a calibration constant was added to match the knock predictions to experimental data. Its value was calculated for three different engines, a light and heavy-duty SI engine and a large-bore dual-fuel engine. They highlight a remarkable difference in calibration constant across the different engines investigated.

An enhanced automated machine learning model for optimizing cycle-to-cycle variation in hydrogen-enriched methanol engines

Renewable methanol and hydrogen have emerged as great potential alternative fuels for internal combustion engines in recent research. Hydrogen exhibits the ability to mitigate cycle-to-cycle variations in methanol engines thanks to its rapid combustion rate. Furthermore, the integration of machine learning with genetic algorithms provides a solution to achieve efficient and clean combustion in hydrogen-enriched methanol engines. Nevertheless, this approach is constrained due to the limited predictive accuracy in small-sample learning. This study aims at introducing an enhanced model based on the automated machine learning framework, and provide a comparative analysis of the enhanced model and computational fluid dynamics simulations in terms of multi-objective optimization performance and computational time. Additionally, this study further considered the effect of engine cycle-to-cycle variations on performance, ultimately attaining optimal operating parameters for stable combustion. The results indicate that datasets actively created by genetic algorithms are more effective than those generated through Latin hypercube sampling. The introduction of a classification model for the identification of misfires has enhanced the efficiency of dataset utilization. Through feature construction, the automated machine learning model demonstrates improvements in R-square and mean-squared error for all parameters on the test dataset. Furthermore, by employing a larger overall population size, the automated machine learning model has not only achieved a higher-quality Pareto fronts compared to the computational fluid dynamics method but has also significantly reduced computation time, particularly upon introducing additional engine cycle-to-cycle variations constraints.

Study on methanol-hydrogen engine in extended-range electric vehicles

The demand for clean and efficient new vehicle models is steadily increasing. Methanol-hydrogen engines use methanol as the main fuel and can recover the heat from engine exhaust to dissociate part of methanol into hydrogen-rich syngas. The syngas is recirculated back into the engine cylinder to improve combustion. Therefore, methanol-hydrogen engines have a higher energy utilization efficiency. This paper designed a methanol-hydrogen engine system based on a Miller cycle methanol engine. Bench tests showed that combusting methanol and dissociated methanol gas together could accelerate the fuel burn rate and improve the engine’s fuel economy. At a fixed engine speed of 2500 r/min, the BSFC of the methanol-hydrogen engine was reduced up to 5.55% compared to the original methanol engine. Further, a methanol-hydrogen extended-range electric vehicle powertrain model was built in Simulink. Simulation results indicated that, under the WTLC cycle, the methanol-hydrogen engine achieved a 22.60% reduction in fuel consumption per 100 km and saved 58.89% in fuel costs compared to the conventional gasoline engine. The methanol-hydrogen engine presented potential application in the extended-range electric vehicle.

Experimental study on the emission characteristic of a methanol engine based on transient cycle WHTC

The emission characteristics of regulated emissions and unregulated emissions were studied under the full loads and the cold/hot transient cycle (WHTC) on a six-cylinder, multi-point injection, and spark ignition methanol engine. The results show that the emissions of THC and CO for the methanol engine is at a high level without three-way catalyst (TWC) and the emission of NOX could be controlled at a lower level than 400 mg/kW·h with exhaust gas recirculation (EGR). The emissions of THC, CO and NOX are low with TWC, whose weighted results under WHTC could be kept at a lower level than the limits in China VI Standard. It is a technical difficulty to control the emissions of methanol (CH3OH) and formaldehyde (HCHO) for methanol engines, especially under the cold WHTC, there has a high risk for the emission of CH3OH exceeding the limit of standard.

Methanol Combustion Characteristics in Compression Ignition Engines: A Critical Review

Methanol has been identified as a transition fuel for the decarbonisation of combustion-based industries, including automotive and maritime. This study aims to conduct a critical review of methanol combustion in compression ignition engines and analyse the reviewed studies’ results to quantify methanol use’s impact on engine performance and emissions characteristics. The diesel and diesel–methanol operation of these engines are comparatively assessed, demonstrating the trade-offs between the methanol fraction, the key engine performance parameters, including brake thermal efficiency, peak in-cylinder pressure, heat release rate, and temperature, as well as the carbon dioxide, carbon monoxide, nitrogen oxides, and particulate matter emissions. The types of the reviewed engines considering the main two combustion methods, namely premixed and diffusion combustion, are discussed. Research gaps are identified, and recommendations for future research directions to address existing challenges for the wider use of methanol as a marine fuel are provided. This comprehensive review provides insights supporting methanol engine operation, and it is expected to lead to further studies towards more efficient use of methanol-fueled marine engines.

Computational study of added H2 impacts on mixture formation, OH radical and unregulated emissions of spark-ignition methanol engine under various boundary parameters

Numerical simulations of hydrogen (H2) impacts on mixture formation, OH radical generation, and formaldehyde (HCHO) and unburned methanol (CH3OH) emissions of spark-ignition (SI) methanol engine based methanol late-injection strategy under different methanol injection timings (MIT), ignition timings (IT), excess air ratios (λ) and added H2 ratios (RH2) boundary parameters were conducted. The simulation results show that the ideal methanol concentration distribution is obtained at the MIT = 85°CA BTDC. The OH radical plays a dominant role in methanol oxidation. The OHPMF (peak OH radical mass fraction) of RH2 = 9 % ≫ OHPMF of RH2 = 6 % > OHPMF of RH2 = 3 % > OHPMF of RH2 = 0 % at MIT = 85°CA BTDC. Compared with IT and λ, the RH2 is more decisive for the generation of OH radical. The HCHO is a major intermediate and an important unregulated emission of methanol engine. In the initial stage of methanol reaction, added H2 can accelerate the generation of OH radical, further promote the oxidation of methanol, and greatly raise the generation of HCHO. The peak HCHO mass fraction increases with the increase of RH2. At MIT = 85°CA BTDC and exhaust valve opening, the HCHO emission of RH2 = 3 %, 6 %, and 9 % is approximately 51 %, 76.5 % and 89.4 % lower than that of RH2 = 0 %, respectively. The generation and post-oxidation of HCHO mainly depended on average in-cylinder temperature. There is a lowest CH3OH emission at MIT = 85°CA BTDC, IT = 28°CA BTDC, λ = 1.4 and pure methanol. At MIT = 85°CA BTDC, λ = 1.4 and exhaust valve opening, the CH3OH emission of RH2 = 3 %, 6 %, and 9 % is approximately 52.8 %, 75.5 % and 92.5 % lower than that of RH2 = 0 %, respectively.

Decarbonising international shipping – A life cycle perspective on alternative fuel options

This study aimed to compare hydrogen, ammonia, methanol, and waste-derived biofuels as shipping fuels using life cycle assessment, to establish what potential they have to contribute to the shipping industry’s 100% greenhouse gas emission reduction target. A novel approach was taken where the greenhouse gas emissions associated with one year of global shipping fleet operations was used as a common unit for comparison, therefore, allowing the potential life cycle greenhouse gas emission reduction from each fuel option to be compared relative to Paris Agreement compliant targets for international shipping. The analysis uses life cycle assessment, from resource extraction to use within ships, with all GHGs evaluated for a 100-year time horizon (GWP100).Green hydrogen, waste-derived biodiesel, and bio-methanol are found to have the best decarbonisation potential, with potential emission reductions of 74–81%, 87%, and 85–94% compared to heavy fuel oil; however, some barriers to shipping’s decarbonisation progress are identified. None of the alternative fuels considered are currently produced at a large enough scale to meet shipping’s current energy demand, and uptake of alternative fuel vessels is too slow considering the scale of the challenge at hand. The decarbonisation potential from alternative fuels alone is also found to be insufficient, as no fuel option can offer the 100% emission reduction required by the sector by 2050.The study also uncovers several sensitives within the life cycles of the fuel options analysed, that have received limited attention in previous life cycle investigations into alternative shipping fuels. First, the choice of allocation method can potentially double the life cycle greenhouse gas emissions of e-methanol due to the carbon accounting challenges of using waste carbon dioxide streams during fuel production. This leads to concerns related to the true impact of using carbon dioxide captured from fossil-fuelled processes to produce a combustible product, due to the resultant high downstream emissions. Second, nitrous oxide emissions from ammonia combustion are found to be highly sensitive due to high greenhouse gas potency, potentially offsetting any greenhouse reduction potential compared to heavy fuel oil. Further uncertainties are highlighted due to limited available data on the rate of nitrous oxide production from ammonia engines. The study therefore highlights an urgent need for the shipping sector to consider these factors when investing in new ammonia and methanol engines; failing to do so risks jeopardizing the sector’s progress towards decarbonisation.Finally, whilst alternative fuels can offer good decarbonisation potential (particularly waste derived bio-methanol and bio-diesel, and green hydrogen), this cannot be achieved without accelerated investment in new and retrofit vessels, and new fuel supply chains: the research concludes that existing pipeline of vessel orders and fuel production facilities is insufficient. Furthermore, there is a need to integrate alternative fuel uptake with other decarbonisation strategies such as slow steaming and wind propulsion.

Effects of methanol direct injection and high compression ratio on improving the performances of a spark-ignition passenger car engine

The high octane number and high latent heat of vaporization of methanol are beneficial to suppress knock and consequently increase compression ratio (CR) of spark ignition engines, and thus improve the thermal efficiency. Few preious research on methanol engine combuston and performances have been conducted based on spark-ignition passenger car engines with a CR greater than 14. In this study, a 1.5-liter spark ignition passenger car engine with miller cycle was used to explore the potentials of high CR and methanol direct injection (MDI) on improving engine performances. First, the engine was tested under stoichiometric combustion using methanol and gasoline at BMEPs of 1.1 MPa and 1.5 MPa with CR11.5, CR13.8, and CR15.3. Then, the performances of the CR11.5 case with gasoline and the CR15.3 case with methanol were compared under lean burn combustion. The results show that for gasoline, increasing CR from 11.5 to 15.3 results in decreased fuel economy under stoichiometric combustion, whereas the exact opposite tendency is shown for methanol. Integrating a high CR of 15.3 and MDI improves brake thermal efficiency (BTE) to 43.3 % at an excess air/fuel ratio (λ) of 1.0, when compared with 37.4 % of gasoline at CR11.5. Applying lean burn can further improve the BTE of methanol at CR15.3 to 44.9 %. The main causes of the improvement of BTE by high CR and MDI are the reduced exhaust heat loss resulted from earlier combustion phasing. However, high CR and MDI also extend combustion durations at all specified λs, and emit more THC and CO emissions than low CR with gasoline at high λs because of higher surface/volume ratio and flame quenching. The extended combustion duration and the incomplete combustion are the main barriers to greater BTE for MDI sprak ignition engine with high CR.

Experimental and kinetic study of methanol reforming and methanol-syngas co-oxidation at high pressure

Using engine exhaust heat to partially convert methanol to syngas and then co-combust is a favored strategy to optimize combustion in methanol engines. In the present work, experiments of methanol pyrolysis and methanol-syngas oxidation were conducted using flow reactors at 1.0–5.0 MPa. The substitution ratio of syngas to methanol varied from 0 to 50%. Experimental results show that high pressure slightly promotes methanol pyrolysis and reduces CH2O generation; syngas inhibits methanol oxidation and reduces CH2O generation. Otherwise, experimental results were used to validate the recently published methanol model, and Mech15.34 captures the experimental data well. The kinetic analysis revealed the effects of substitution ratio on methanol-syngas co-oxidation can be divided into dilution and chemical effects. The dilution effect refers to the reduction of methanol, which directly decreases the CH2O generation. The chemical effect refers to the competition of H2 and CO for OH radicals, which decelerates the CH3OH oxidation. Meanwhile, the reaction H2O2 + H = H2 + HO2 proceeds in reverse direction with H2 blending, generating more H radicals, which enhances the CH2O consumption through the reaction CH2O + H = HCO + H2.

Improving the lean burn performance of a high compression ratio methanol engine by multiple-injection

Methanol is a promising fuel for achieving carbon neutrality in sectors requiring internal combustion engines. The multiple-injection approach is effective in reducing cycle-to-cycle variations and improving the performance of methanol engines under lean burn conditions. This study proposes a concept for transforming diesel engines into methanol engines with flexible injection and lean burning capabilities. This study fills the research gap in the study of lean methanol combustion in swirl combustion chambers. The effects of 22 different multiple-injection strategies on combustion characteristics, emission performance, and combustion stability are experimentally assessed in a direct-injection spark ignition engine with an excess air ratio (λ) of 1.35. Each multiple-injection strategy is comprehensively evaluated using a merit function and compared with the baseline case that uses single injection. The results show that the double- and triple-injection strategies substantially shorten the durations of combustion and flame development. Therefore, a higher effective expansion ratio is obtained. Meanwhile, the cycle-to-cycle variation in the IMEP decreases from 4.2% of the baseline to 1.49% at T8. CO and HC emissions deteriorate; however, NOx and CO2 emissions under triple injection are lower than those under the baseline. The T7 case with triple injection achieves the highest thermal efficiency, which is 6.8% higher than that for the baseline case. Overall, triple injection achieves higher merit function values, which indicates a better capability to improve lean-burn performance than double injection.

Study on Compression Ratio Optimization of M100 Methanol Engine

A turbocharged and intercooled diesel engine was transformed into an ignited M100 methanol engine by adding a spark plug to the cylinder head. A one-dimensional model of the methanol fuel engine was established using the bench test data as the boundary conditions, and the accuracy and accuracy of the model were verified. Methanol has better octane number and explosion resistance than traditional fuels, increasing the compression ratio of the engine will improve the power and fuel efficiency of the methanol engine. Based on the original compression ratio of 12, 8 compression ratio simulation schemes were selected, including 11.4, 11.7, 12, 12.3, 12.6, 12.9, 13.2, 13.5, etc., and the engine performance and the combustion state in the cylinder changed with the compression ratio were analyzed by simulation calculation, and the engine was optimized and improved. The results show that when the engine compression ratio reaches 12.9, the engine performance reaches the optimal value.

Methanol as a Marine Fuel for Greener Shipping: Case Study Tanker Vessel

_ The present paper proposes using methanol fuel in ships to meet emissions regulations established by the International Maritime Organization. An analysis of the use of twin fuel engines operated by diesel and methanol has been conducted from environmental and cost-effective viewpoints. As a case study, a tanker vessel operated by two fuels was investigated. The environmental results showed decreases in SOx, NOx, PM, CO2, and CO pollutant emissions by 90%, 76.80%, 83.49%, 6.43%, and 55.63%, respectively. A selective catalytic reduction (SCR) measure is installed onboard the vessel to decrease NOx emissions in case diesel fuel is used. Economically, the dual-fuel engine will save on SCR costs. The cost-effectiveness values for using a methanol engine will be $242.3/ton and $764.7/ton for reducing CO2 and NOx emissions, respectively. Finally, the cost-effectiveness for reducing NOx emissions using SCR system is $536.6/ton for the conventional diesel engine. Introduction The majority of all cargo delivered worldwide is transported by sea (Zhou et al. 2020; Aarflot et al. 2022). Petroleum and other liquid fuels are the dominant sources for transporting this cargo. According to the International Maritime Organization (IMO), worldwide ships consume 309 million tons of fuel annually. These fuel consumptions result in yearly emissions of 11 million tons of sulfur oxides (SOx), 22 million tons of nitrogen oxides (NOx), 1.71 million tons of particulate matter (PM), 1056 million tons of carbon dioxide (CO2), and 844 million tons of carbon monoxide (CO) (IMO 2020). These emissions contribute to air pollution and climate change, highlighting the need for more sustainable shipping practices.