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An experimental investigation is carried out on conventional compression ignition engines' combustion, performance, and emission characteristics using Conventional Dual Fuel (CDF) combustion and reactivity-controlled compression ignition (RCCI) combustion strategies. The experiments are performed on a variable-speed production-grade diesel engine converted to a research engine. Comparative combustion analysis shows that RCCI combustion is more stable and shows a consistent ignition delay across all engine speeds. The exhaust gas temperature of RCCI combustion is lower than that of CDF combustion and is in the range of Conventional Diesel Combustion (CDC). CDC shows better brake thermal efficiency (BTE) than CDF and RCCI combustion across all engine speeds, followed by RCCI combustion. The lowest BTE is observed in CDF combustion. Emission results show that RCCI combustion produced significantly lower NOx emissions than CDC at low engine speed without much HC and CO emissions increment. RCCI combustion does not effectively reduce NOx emissions and produces higher HC and CO emissions at high engine speeds. A BTE-NOx trade-off analysis is also carried out, demonstrating the suitability of RCCI combustion at low engine speed. CDC under high engine speed conditions and in the transition region of medium engine speed CDF combustion is more favorable to reduce NOx emission.

The results of diagnostic tests under steady-state speed conditions of an unloaded engine do not fully reflect the emissivity of vehicles adapted to run on natural gas. Therefore, it is reasonable to pay attention to the emissions performance of these vehicles under dynamic conditions. In this regard, the tests were carried out on a chassis dynamometer with the engine fueled by gasoline and natural gas. Due to the area of operation of natural gas vehicles being usually limited to urban areas, the urban phases of the NEDC (New European Driving Cycle) and WLTC (Worldwide harmonized Light-duty vehicles Test Cycle) were adapted. While CO2 emissions are lower when fueled by natural gas, CH4 emissions can be high, which is related to momentary changes in the composition of the combustible mixture. Although CH4 emissions are higher when the engine runs on natural gas, the CO2eq value is, depending on the driving cycle, about 15–25% lower than when running on petrol. Additionally, studies have shown that in engines adapted to run on CNG (compressed natural gas), it is advisable to consider the use of catalytic converters optimized to run on natural gas, as is the case with vehicles which are factory–adapted to run on CNG. [ABSTRACT FROM AUTHOR]

In response to increasingly stringent global environmental policies, this study addresses the pressing need for accurate prediction models of CO2 emissions from vehicles powered by alternative fuels, such as compressed natural gas (CNG). Through experimentation and modelling, one of the pioneering CO2 emission models specifically designed for CNG-powered vehicles is presented. Using data from chassis dynamometer tests and road assessments conducted with a portable emission measurement system (PEMS), the study employs the XGBoost technique within the Optuna Python programming language framework. The validation of the models produced impressive results, with R2 values of 0.9 and 0.7 and RMSE values of 0.49 and 0.71 for chassis dynamometer and road test data, respectively. The robustness and precision of these models offer invaluable information to transportation decision-makers engaged in environmental analyses and policymaking for urban areas, facilitating informed strategies to mitigate vehicular emissions and foster sustainable transportation practices. [ABSTRACT FROM AUTHOR]

This paper presents a theoretical analysis of the selected properties of HCNG fuel calculations and a literature review of the other fuels that allow the storage of ecologically produced hydrogen. Hydrogen has the most significant CO2 reduction potential of all known fuels. However, its transmission in pure form is still problematic, and its use as a component of fuels modified by it has now become an issue of interest for researchers. Many types of hydrogen-enriched fuels have been invented. However, this article will describe the reasons why HCNG may be the hydrogen-enriched fuel of the future and why internal combustion (IC) piston engines working on two types of fuel could be the future method of using it. CO2 emissions are currently a serious problem in protecting the Earth's natural climate. However, secondarily, power grid stabilization with a large share of electricity production from renewable energy sources must be stabilized with very flexible sources—as flexible as multi-fuel IC engines. Their use is becoming an essential element of the electricity power systems of Western countries, and there is a chance to use fuels with zero or close to zero CO2 emissions, like e-fuels and HCNG. Dual-fuel engines have become an effective way of using these types of fuels efficiently; therefore, in this article, the parameters of hydrogen-enriched fuel selected in terms of relevance to the use of IC engines are considered. Inaccuracies found in the literature analysis are discussed, and the essential properties of HCNG and its advantages over other hydrogen-rich fuels are summarized in terms of its use in dual-fuel (DF) IC engines. [ABSTRACT FROM AUTHOR]

Copyright of Mechanical & Electronic Control Engineering is the property of Omniscient Pte. Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The energy crisis and the threat of global climate change have spurred various research efforts and alternative initiatives to find substitutes for fossil fuels, improve energy efficiency, and reduce emissions, especially greenhouse gases. The shipping industry is one of the contributors to global emissions that has received particular attention due to the increasing demand for maritime transportation services. The use of natural gas is considered a potential solution due to its relatively clean nature, abundant availability, and competitive pricing. The CNG-Diesel Dual Fuel Engine design is developed with the principle of using natural gas as an alternative fuel without replacing the existing diesel engine. Minimal modifications are made to the intake manifold to accommodate CNG entry. Despite its advantages, the development of dual fuel engines faces challenges, such as increased methane emissions due to the potential for incomplete combustion. This research conducts experimental studies on the use of a Venturi-like mixer in the intake manifold to enhance the homogeneity of the CNG-air mixture before entering the combustion chamber. Testing the mixer's influence is carried out under various CNG injection durations at low and high engine loads at constant speeds. The results indicate that the addition of the mixer does not immediately improve combustion quality or reduce emissions. Attention to conditioning the homogenous mixture at the required air-fuel ratio before entering the combustion chamber is crucial. The selection of the appropriate mixer design, diameter size, and placement of holes needs careful consideration

The main objective of the paper is to reveal a few aspects related to combustion quality of a diesel engine fueled in diesel-gas mode with diesel fuel and compressed natural gas. The total amount of heat released per cycle will be higher when the engine is fueled in dual-fuel mode due to higher LHV and because of the gaseous state of CNG. For low and medium loads the total quality of heat released per cycle will increase with 10 % and for higher loads it will reach levels with 25 % higher. The heat release rate of the preformed mixture will double its value for low and medium loads and will reach thresholds up to 3.5 times higher (interval −15; −5°CA); admitting CNG into cylinder will help the preformed mixture to reach stoichiometric values and thus improving the fast combustion phase. Fueling the engine in dual fuel mode with diesel fuel and CNG will have a negative effect on the maximum heat release rate; there will be a 10 % drop in maximum HRR for low loads when the energetic substitution coefficient reaches 36 % and 14 % at high loads when the xc is 26 %. The gaseous state and a higher LHV of CNG will have a good impact on indicated mean effective pressure for all studied regimes when the engine is fueled in DG mode: for low and medium loads 30 % and for high loads 20 % increase will be recorded. Gaseous state of CNG will lead to a higher percentage of preformed mixture and thus the fast combustion phase will extend for longer periods for all studied regimes when the engine is fueled in DG mode (20 % longer for low and medium loads and 30 % for high loads). The diffusive combustion phase will become shorter due to a lower quantity of the main dose when CNG is injected into the intake manifold (10–15 % shorter for low loads and 7 % at high loads).

Abstract The use of CNG auto-rickshaws is increasing in Dhaka, the capital of Bangladesh. CNG auto rickshaws are a crucial component of the transportation system of Dhaka City. These offer the dwellers a quick and affordable way to navigate the city’s congested streets. This study aims to determine how commuters in Dhaka City perceive the quality of app-based CNG auto rickshaw service. A structured questionnaire is developed based on the users’ reported attitudes and perceived risks. In order to comprehend how users feel about an app-based CNG auto rickshaw service, collected data were used to create a Structural Equation (SE) model. The responses are also evaluated using the Relative Importance Index (RII) method, which validates the SE model. The study shows that women’s safety and better safety experience are the most significant parameters while accepting app-based CNG auto rickshaw services. The results of this study will help the service providers involved in this operation better understand the best course of action to be taken in order to provide better service to commuters.

The energy mix determines the external costs of transport and the benefits from investments in the drive systems perceived as more environmentally friendly, such as electric vehicles.

The use of CNG auto-rickshaws is increasing in Dhaka, the capital of Bangladesh. CNG auto rickshaws are a crucial component of the transportation system of Dhaka City. These offer the dwellers a quick and affordable way to navigate the city's congested streets. This study aims to determine how commuters in Dhaka City perceive the quality of app-based CNG auto rickshaw service. A structured questionnaire is developed based on the users' reported attitudes and perceived risks. In order to comprehend how users feel about an app-based CNG auto rickshaw service, collected data were used to create a Structural Equation (SE) model. The responses are also evaluated using the Relative Importance Index (RII) method, which validates the SE model. The study shows that women's safety and better safety experience are the most significant parameters while accepting app-based CNG auto rickshaw services. The results of this study will help the service providers involved in this operation better understand the best course of action to be taken in order to provide better service to commuters. [ABSTRACT FROM AUTHOR]

Ground-level ozone contamination has been globally an urban air quality issue, particularly for China, which has recently made significant progress in purifying its sky. Unregulated exhaust emissions from motor vehicles, predominantly carbonyls and volatile organic compounds (VOCs), are among the leading contributors to ozone formation. In this chassis-level study, the unregulated emissions from five China-5 certified gasoline/CNG bi-fuel taxis, along with their ozone forming potential (OFP), were evaluated. It is found that carbonyls and VOCs were mainly emitted during the starting phase no matter the engine was cold or hot. Compared to gasoline, CNG fueling reduced VOCs emissions on a large scale, especially in the starting phase, but had elevated carbonyls. On a fleet average, CNG fueling derived 15% and 46% less OFP than gasoline in cold- and hot-start tests, respectively. VOCs contributed to over 90% of the total OFP of the exhaust. In terms of alleviating ground-level ozone contamination, CNG is a feasible alternative to gasoline on light-duty vehicles. [ABSTRACT FROM AUTHOR]

The gas fuels are from many aspects more convenient for use than liquid fuels. First of all, the gas fuels are already in gaseous aggregate state, so it is not necessary the vaporization, the mixing is easier, and by that the formation of homogenous mixture is much easier, than in the case of liquid fuels. Also, the gas fuels are considered to be more perspective fuels, due their chemical composition. In most cases, the gas fuels have less carbon in their chemical composition, which is good from the aspect of the ecology. Less carbon leads to the lower emission of harmful components such are carbon-monoxide (CO) and unburnt-hydrocarbons (HC). In this paper, experimentally was investigated the IC engine working cycle with the Compressed Natural Gas (CNG), for the cases of stratified mixture. It was found out that the degree of the stratification, greatly influences on the combustion process, and in this way on the IC engine efficiency. [ABSTRACT FROM AUTHOR]

An engine with common-rail direct injection diesel uses Hydrogen and hydrogen-enriched CNG to investigate their possible usage. The engine's air intake manifold delivers hydrogen/CNG and hydrogen mixes. Different injection pressures (three) and at higher load are used to test out the different engine output parameters. In dual and single-fuel operations with diesel, dual-fuel operations produce higher in-cylinder pressure (73.39 bar) and shown better combustion. Due to induction of dual fuel, there is large variability in ignition delay and combustion duration compared to pure diesel. Enriching hydrogen reduces specific fuel usage. Significant reduction in engine pollutants is observed in dual fuel mode compared to diesel fuel. Hydrogen substitutes reduce THC and CO 2 emissions by 30–35% and 3–4% respectively. Dual-fuel operations emit less smoke (5–10%) in different injection pressure than diesel. At all injection pressure the different combustion parameters, performances (37.2% better than D100) and emissions like NOx, CO 2 , and smoke are better for all dual-fuel than diesel at rated load for the different fuel approach type two (DFA2). • In a CRDI engine, hydrogen and CNG mixtures are tested better performance and to control emissions. • At the rated load with three different injection pressures, the ignition delay for operations using dual-fuel is reduced. • For all the injection pressure combustion duration is better for DFA1, DFA2, and DFA3 than conventional diesel. • Enriching hydrogen results in lower emissions of THC, CO2, and other green-house gases. • Change in injection pressure significantly reduces emissions of smoke, CO2, and NOx, in vehicles with dual-fuel. [ABSTRACT FROM AUTHOR]

The energy mix determines the external costs of transport and the benefits from investments in the drive systems perceived as more environmentally friendly, such as electric vehicles. The aim of this article was to present a methodology to determine the environmentally preferable urban bus drive systems (electric, hydrogen, CNG, hybrid, plug-in hybrid, and diesel) depending on CO2 emission factors related to the production of electricity in a given country. The developed methodology was exemplified by the Polish energy system. The results indicate the environmentally preferable types of urban bus drive systems, taking into account vehicle exploitation. The results obtained can inform the decision-making process and, in particular, enable state administrations in EU countries to define a support mechanism for public transport (e.g., through subsidies) that is appropriate to the environmental benefits of operating particular types of vehicles under country-specific energy mix conditions. [ABSTRACT FROM AUTHOR]

Compressed Natural Gas (CNG) is an environmentally friendly alternative fuel that is affordable with high octane value. Although numerous preliminary studies have been developed about CNG, none examines engine vibrations on human body comfort. Based on these problems, this research proposes an experimental method to observe engine vibration characteristics in developing a CNG engine control system for human body comfort. In the first test, the vehicle was evaluated at an environmental temperature of 18 °C and air humidity of 98 %. The second method tested it at environmental temperature of 23 °C and air humidity of 73 %. The results of the first method test showed that the machine vibration amplitude on the x-axis decreased from (2.82–2.25 mm) to (0.85–0.82 mm). The Comfort Index (CI) assessment consisted three checks, namely vibration acceleration, vibration frequency and damping. Vibration acceleration was in a cluster close to III with a maximum threshold value of 4 h for engine vibration. Meanwhile, the test results of the second method showed that the vibration amplitude in the x-axis decreased from (2.82–2.35 mm) to (0.85–0.81 mm. The Comfort Index (CI) assessment was close to cluster II with the threshold value maximum limit of 6 h for engine vibration. The decrease in CI in the second test method was because the second test had a higher environmental temperature and lower humidity. The density of the air/CNG significantly influenced the engine speed and vibration acceleration. This research failed to test ignition angles with various positions, lean and rich AFR, or fuel consumption. Therefore, in future research, is needed to consider these variables.

Aim: The purpose of this article is to present the most important information and conclusions about gas-powered motor vehicles and the associated risks during fires and local emergencies. An additional area of consideration for the article’s authors is the challenges that emergency services may encounter during rescue and firefighting operations involving such vehicles. Introduction: Technological advances in propulsion systems used in vehicles and machinery pose a variety of challenges for fire protection. It results in the evolution of known threats and the emergence of new ones. Among other things, these developments have a significant impact on the technologies of rescue operations during fires and traffic accidents involving vehicles with different propulsion systems (increasingly using gaseous fuels). Equally important is ensuring fire safety when operating such vehicles. Methodology: On the basis of a review and analysis of the literature on the subject, as well as available research results, conclusions have been formu- lated regarding the fire safety of gas-powered vehicles. Aspects relevant to conducting rescue and firefighting operations involving such vehicles were taken into account. Conclusions: Necessary measures to improve fire protection, including the conduct of effective rescue and firefighting operations during incidents involving alternatively powered vehicles include: 1. Keeping as accurate a record as possible of fires and local emergencies involving the vehicles in question. 2. Urgently developed and updated educational materials that allow training, both for the rescuers and commanders of KSRG units, in blended learning mode, and systematically conducted such training. An example of this is the educational platform prepared by CNBOP-PIB in 2009 for OSP rescuers (rescue operations) and rural residents (handling emergency situations). The platform is still in place today, and although it needs updating, it has been used successfully for many years for training and professional development of a wide range of the rescuers. 3. A rescue database of vehicles involved in incidents urgently prepared and made available to the rescuers of firefighting units that are part of the KSRG. Such a base should be established immediately or be available on terms convenient to the rescue units (such as CRS or ERG). Keywords: alternative propulsion, CNG, LNG, methane, LPG, ethane, propane, methanol, fuel cells, emergency cards, fire safety

The article analyzes the modern theory and practice of transportation and storage of compressed natural gas. The expediency of the inclusion of a floating storage berth for the loading of gas carriers and container ships into the infrastructure of marine transportation of compressed natural gas is considered. Requirements for storage berth are formulated. It is shown that without using a marine mooring storage facility, the loading time of a gas carrier will considerably increase, and the economic efficiency of compressed gas transportation will lower due to the considerable time of loading and unloading of a gas carrier. The construction of a storage berth is proposed, and calculations of storage parameters and calculation of its buoyancy are made. The possibility of using the REFPROP vs. 9.1 software package to automate the selection of the composition of a multicomponent hydrocarbon mixture for further use at the selected range of temperatures and pressures is substantiated. The use of the system is considered in the example of phase equilibrium of a multicomponent hydrocarbon mixture. [ABSTRACT FROM AUTHOR]

Copyright of Energy Policy Journal / Polityka Energetyczna is the property of Mineral & Energy Economy Research Institute of the Polish Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The addition of Compressed natural gas as a complement to diesel in compression ignition engines in dualfuel combustion mode is a viable technology for increasing efficiency and lowering emissions. This work investigates the impact of a dual-fuel operating mode on the engine exhaust pollutant emissions of a diesel engine using compressed natural gas as the principal fuel and neat diesel as the pilot fuel. Compressed natural gas was injected into an intake manifold of a single-cylinder diesel test engine under different engine operating parameters, and up to 80% substitution was attained. And diesel fuel was injected after the compressed natural gas air mixture was compressed. The tests were carried out at five different compression ratios ranging from 13:1 to 15:1 in steps of 0.5:1. The experiment study revealed that injecting CNG into diesel engines via dual fuel combustion significantly impacted exhaust gas emissions compared to pure diesel combustion. The Carbon monoxide (CO) and hydrocarbon (HC) emissions were increased, while carbon dioxide (CO2), nitrogen oxide (NOX) and smoke opacity were decreased in dual fuel combustion compared to single diesel fuel. [ABSTRACT FROM AUTHOR]

Biogas consisting primarily of methane (CH4) and carbon dioxide (CO2) can be upgraded to a transportation fuel referred to as renewable natural gas (RNG) by removing CO2 and other impurities. RNG has energy content comparable to fossil compressed natural gas (CNG) but with lower life-cycle greenhouse gas (GHG) emissions. In this study, a light-duty cargo van was tested with CNG and two RNG blends on a chassis dynamometer in order to compare the toxicity of the resulting exhaust. Tests for reactive oxygen species (ROS), biomarker expressions (CYP1A1, IL8, COX-2), and mutagenicity (Ames) show that RNG exhaust has toxicity that is comparable or lower than CNG exhaust. Statistical analysis reveals associations between toxicity and tailpipe emissions of benzene, dibenzofuran, and dihydroperoxide dimethyl hexane (the last identification is considered tentative/uncertain). Further gas-phase toxicity may be associated with tailpipe emissions of formaldehyde, dimethyl sulfide, propene, and methyl ketene. CNG exhaust contained higher concentrations of these potentially toxic chemical constituents than RNG exhaust in all of the current tests. Photochemical aging of the vehicle exhaust did not alter these trends. These preliminary results suggest that RNG adoption may be a useful strategy to reduce the carbon intensity of transportation fuels without increasing the toxicity of the vehicle exhaust.

The uncertainty in the supply of crude oil, increasing the number of vehicles and rising air pollution, especially in urban areas, has prompted us to look for alternative fuels. It is understood that using Compressed Natural Gas (CNG) in IC engines could be a mid-term solution to these problems. It is well established that CNG has better combustion characteristics and low emissions compared to conventional gasoline and diesel fuel. In the present study, an experiment was conducted to evaluate the engine performance and exhaust emissions using various percentages of CNG in dual fuel mode. CNG was mixed in the intake manifold’s air stream, and diesel was injected after the compression of the CNG air mixture. This paper presents experimental results of 40%,60%, and 80% CNG in the air stream. Engine performance and emissions are presented and discussed at a speed of 1200 rpm to 1500 rpm in steps of 50 rpm. The results of the experiments showed that adding CNG to diesel engines in dual-fuel combustion significantly impacted performance and emissions. Compared to single diesel fuel combustion, dual fuel combustion increases brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC) at all CNG energy shares and engine speeds. Carbon monoxide (CO) and hydrocarbon (HC) emissions were increased, while nitrogen oxide (NOX) and smoke opacity were decreased in dual fuel combustion compared to single diesel fuel.

The results of diagnostic tests under steady-state speed conditions of an unloaded engine do not fully reflect the emissivity of vehicles adapted to run on natural gas. Therefore, it is reasonable to pay attention to the emissions performance of these vehicles under dynamic conditions. In this regard, the tests were carried out on a chassis dynamometer with the engine fueled by gasoline and natural gas. Due to the area of operation of natural gas vehicles being usually limited to urban areas, the urban phases of the NEDC (New European Driving Cycle) and WLTC (Worldwide harmonized Light-duty vehicles Test Cycle) were adapted. While CO2 emissions are lower when fueled by natural gas, CH4 emissions can be high, which is related to momentary changes in the composition of the combustible mixture. Although CH4 emissions are higher when the engine runs on natural gas, the CO2eq value is, depending on the driving cycle, about 15–25% lower than when running on petrol. Additionally, studies have shown that in engines adapted to run on CNG (compressed natural gas), it is advisable to consider the use of catalytic converters optimized to run on natural gas, as is the case with vehicles which are factory–adapted to run on CNG.

In response to increasingly stringent global environmental policies, this study addresses the pressing need for accurate prediction models of CO2 emissions from vehicles powered by alternative fuels, such as compressed natural gas (CNG). Through experimentation and modelling, one of the pioneering CO2 emission models specifically designed for CNG-powered vehicles is presented. Using data from chassis dynamometer tests and road assessments conducted with a portable emission measurement system (PEMS), the study employs the XGBoost technique within the Optuna Python programming language framework. The validation of the models produced impressive results, with R2 values of 0.9 and 0.7 and RMSE values of 0.49 and 0.71 for chassis dynamometer and road test data, respectively. The robustness and precision of these models offer invaluable information to transportation decision-makers engaged in environmental analyses and policymaking for urban areas, facilitating informed strategies to mitigate vehicular emissions and foster sustainable transportation practices.

This paper presents a theoretical analysis of the selected properties of HCNG fuel calculations and a literature review of the other fuels that allow the storage of ecologically produced hydrogen. Hydrogen has the most significant CO2 reduction potential of all known fuels. However, its transmission in pure form is still problematic, and its use as a component of fuels modified by it has now become an issue of interest for researchers. Many types of hydrogen-enriched fuels have been invented. However, this article will describe the reasons why HCNG may be the hydrogen-enriched fuel of the future and why internal combustion (IC) piston engines working on two types of fuel could be the future method of using it. CO2 emissions are currently a serious problem in protecting the Earth’s natural climate. However, secondarily, power grid stabilization with a large share of electricity production from renewable energy sources must be stabilized with very flexible sources—as flexible as multi-fuel IC engines. Their use is becoming an essential element of the electricity power systems of Western countries, and there is a chance to use fuels with zero or close to zero CO2 emissions, like e-fuels and HCNG. Dual-fuel engines have become an effective way of using these types of fuels efficiently; therefore, in this article, the parameters of hydrogen-enriched fuel selected in terms of relevance to the use of IC engines are considered. Inaccuracies found in the literature analysis are discussed, and the essential properties of HCNG and its advantages over other hydrogen-rich fuels are summarized in terms of its use in dual-fuel (DF) IC engines.

In this study the authors conducted an evaluation of energy management with the aim of identifying energy consumption used for production process activities in the pharmaceutical industry. Based on data on energy use in the productivity process, the Energy Intensity (EI) value ranges from 0.020-0.695 GJ/kg. From these IE values, in each productivity process the average IE value can be used as a reference as an energy conservation limit value of 0.125 GJ/kg. From the description of the pattern of total energy consumption, it can be seen that the use of electrical energy tends to be greater, namely around 66.37% compared to the consumption of CNG and diesel which only consume 31.80% and 1.83%. The total energy use for electricity is an average of 1,105.56 MWh/month, CNG fuel is 1,895.54 MMBTU/month and diesel is 3.04 liters/month. In terms of equipment systems, the largest electricity consumption is borne by the HVAC system which consumes around 55.56% of the total electrical energy. From the description of the distribution of electrical energy use, it can be said that the HVAC system is SEU (Significant Energy Use). Based on actual conditions, it shows that the actual COP value obtained is 2.49-2.98 with a design deviation of around 1.24%-27.74% and an EER value of 1.18-1.41 kW/TR with a design deviation value of around 1.17%- 38.22%. COP and EER values can still be increased so that performance is more optimal. [ABSTRACT FROM AUTHOR]

Graphical Abstract Concerning the national biofuel policies in India, increasing plant-based fuels and lowering the use of fossil diesel in CI engines reduces the burden on foreign exchange and carbon footprints in the environment, which helps achieve "net-zero carbons emissions." In this present study, Mahua biodiesel (BD) was used here as an ignition energy source, and CNG/ethanol (Et) was used here as the primary energy source replacing the biodiesel with a significant energy share during the combustion process. The effects of various injection and reactivity phasing strategies on a diesel engine's combustion characteristics has been evaluated here. However, effect of this combustion characteristics on the corresponding performance and emission has also been evaluated here. This study revealed the ignition delay (ID) and combustion duration (CD) trade-off for almost every combustion phase achieved here during the testing. This analysis also incorporates the widespread effect of combustion characteristics on the performance and emission behavior of the diesel engine for both types of fuel combinations, that is, CNG + BD and Et + BD operation. For example, the lowest ID for CNG enriched combustion was 26.62% greater than ethanol enriched combustion, signifying that the ethanol delayed the start of ignition at polit-main angle of 35°-05° CA. Hence, NHC, PM, and CO2 emissions registered a lower footprint for CNG-BD operation, while ethanol-BD mode reported lower CO emission. However, ethanol-enriched combustion registered a 31.25% higher maximum CD than CNG-coupled operation, signifying a more extended period of energy release. CNG-BD operation also observed lower NHC, CO, and CO2 footprint corresponding to maximum combustion duration, and ethanol-BD mode reported lower PM emission. [ABSTRACT FROM AUTHOR]

Greenhouse gas (GHG) emissions are the most influential issue in the transportation sector in recent years due to their impact on the environment. Thus, the design of transportation power plants is necessary to ensure the lowest GHG emissions. However, the development of a small vessel power plant is discussed in this study. The small vessel is a marine debris working vessel that has the purpose of collecting marine debris on the water surface with a conveyor. This vessel is designed with a dual-fuel engine fueled by natural gas from CNG and diesel fuel in high load conditions. Furthermore, the power system is designed with a systematical assessment condition based on the operational condition. Moreover, an experiment was conducted to study the performance and emissions of the engine. The hybrid system is designed with several operational conditions, such as sailing, collecting, and maneuvering. Most of the operations can be used in the hybrid dual-fuel system with nearly similar engine torque to diesel mode. The dual-fuel hybrid system has a significantly low engine fuel consumption with low CO2 emissions. However, relatively high NO2 and CO emissions are still considerable.

Aim: The aim of the article is to review information about motor vehicles that use alternative propulsion systems (in this case, electric propulsion) and the risks associated with their use. The discussion of these issues is crucial for undertaking rescue and firefighting operations during incidents (fires, local emergencies) involving alternatively powered vehicles and the effectiveness of these operations. Knowledge in the areas of: hazard identification, improvement of rescue technologies, necessary devices and equipment for effective rescue and firefighting operations during traffic incidents, including fires, with the involvement of vehicles with alternative propulsion systems can be gained from both theoretical and empirical studies. Introduction: Technical and technological advances in the area of drives used in vehicles and machinery pose new challenges for fire protection. They concern, among other things, the technology of rescue operations during fires and traffic accidents involving such vehicles, as well as ensuring fire safety when operating and storing them in buildings, garages and parking areas, and during charging. Methodology: The article was prepared based on national and foreign sources, literature on the subject, research results and the authors’ diverse experiences. It describes the current state of knowledge in terms of hazards and how to deal with them during rescue and firefighting operations against incidents involving alternatively powered vehicles. Conclusions: The number of motor vehicles in Poland and other countries continues to grow, and together with it also the number of vehicles equipped with alternative drives to internal combustion engines (gasoline, diesel). An analysis of the literature on the subject, available research results, as well as individual incidents, lead to the reasonable conclusion that the risks during rescue and firefighting operations associated with the incidents involving electric and hybrid vehicles are no greater than for conventionally powered vehicles. They are different to some extent, which is due in particular to the used power system, which is based on energy storage devices – batteries. Keywords: alternative propulsion, CNG, LNG, methane, LPG, ethane, propane, hybrid propulsion, electric vehicles, fuel cell, rescue, rescue and firefighting operations

Methane is an important greenhouse gas, which constitutes minimum 90% of automotive grade compressed natural gas (CNG) used in India. The use of CNG as automotive fuel has been implemented in almost all major tier I to tier III cities of the country. Delhi, the capital city of India, has world largest CNG-fuelled public transport system. The cylinders fitted to the CNG-fuelled vehicles are required to be subjected to hydrostatic stretch test every 3 years at Government of India approved CNG cylinder testing stations, as mandated under Rule 35 of Gas Cylinders Rules, 2016. During the testing of cylinders, CNG present in the cylinders are discharged in the atmosphere at the degassing point of CNG testing stations. This study estimates annual methane emissions from the CNG cylinder testing stations of Delhi. The annual average methane emission from the CNG cylinder testing stations of Delhi was found to be 30.8 tons during the year 2019. The uncertainties in the emission estimate are also identified and discussed. [ABSTRACT FROM AUTHOR]

One of the issues in urban areas such as DI Yogyakarta province is air pollution. The pollution level is high, as shown by the quality index value of about 85.25 in 2019. Vehicle emissions are the most significant source of this pollution in urban areas and can be decreased by using fuel with minimum carbon emission. Compressed Natural Gas (CNG) is an environmentally friendly fuel. However, a safety study is required because CNG is stored under high pressure. Therefore, this research aims to analyze the risk of using CNG in the Trans Jogja bus. The research method collects secondary data and then processes them using FTA, ETA, ALOHA software, and a risk matrix. The result shows that the risk value for CNG usage in the Trans Jogja bus is low to a moderate level or acceptable.

Compressed Natural Gas (CNG) is an affordable fuel with a higher octane number. However, older CNG kits without electronic controls have the potential to supply more fuel when driving downhill due to the vacuum in the intake manifold. Therefore, this article presents a development of a CNG control system that accommodates road inclination angles to improve fuel efficiency. Machine learning is involved in this work to process engine speed, throttle valve position, and road slope angle. The control system is designed to ensure reduced fuel consumption when the vehicle is operating downhill. The results showed that the control system increases fuel consumption by 25.7% when driving downhill which an inclination of 5ᵒ. The AFR increased from 17.5 to 22 and the CNG flow rate decreased from 17.7 liters/min to 13.8 liters/min which is promising for applying to CNG vehicles.

The visual process begins with the absorption of photons by photopigments of cone and rod photoreceptors in the retina. In this process, the signal is first amplified by a cyclic guanosine monophosphate (cGMP)-based signaling cascade and then converted into an electrical signal by cyclic nucleotide-gated (CNG) channels. CNG channels are purely ligand-gated channels whose activity can be controlled by cGMP, which induces a depolarizing Na+/Ca2+ current upon binding to the channel. Structurally, CNG channels belong to the superfamily of pore-loop cation channels and share structural similarities with hyperpolarization-activated cyclic nucleotide (HCN) and voltage-gated potassium (KCN) channels. Cone and rod photoreceptors express distinct CNG channels encoded by homologous genes. Mutations in the genes encoding the rod CNG channel (CNGA1 and CNGB1) result in retinitis-pigmentosa-type blindness. Mutations in the genes encoding the cone CNG channel (CNGA3 and CNGB3) lead to achromatopsia. Here, we review the molecular properties of CNG channels and describe their physiological and pathophysiological roles in the retina. Moreover, we summarize recent activities in the field of gene therapy aimed at developing the first gene therapies for CNG channelopathies. [ABSTRACT FROM AUTHOR]

Copyright of Current Social & Economic Processes / Jelenkori Társadalmi és Gazdasági Folyamatok is the property of University of Szeged, Faculty of Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The constant development of civilization increases environmental pollution as a result of industrial activity and transport. Consequently, human activity in this area is restricted by regulations governing the permissible emission of harmful substance components into the environment. These include substances emitted by combustion engines, the use of which remains high in many industries. Consequently, research is being conducted to reduce the emissions of harmful exhaust components from existing and newly manufactured internal combustion engines. This research presents a used semi-truck engine, in which an innovative Compressed Natural Gas (CNG) supply system was applied. Using this fuel supply installation allows a mass exchange of the base diesel fuel to natural gas of up to 90%. The study evaluated the effect of the diesel/CNG exchange ratio for different engine operating conditions (engine load, speed) on the concentration of toxic components, such as CO, NO, NO2, NOX, as a sum of NO, NO2, CH4, C2H4, C2H6, C3H8, NH3, and CH2O. The use of a dual-fuel system had a positive effect on the emissions of some harmful exhaust components, even in an engine from a vehicle that had been running for many years on diesel and at high mileage, but, simultaneously, the emissions of some harmful exhaust gas components increased. [ABSTRACT FROM AUTHOR]

Due to the required clearance between the cylinder liner and piston of a reciprocating IC engine, a few crevices appear among compression rings and cylinder-piston. Although the gas leakage into the crankcase can be controlled substantially via the use of two or three compression rings, it is impossible to remove the existing crevices and the ring orifices of the cylinder-piston-ring pack. Escape of unburned mixture into the crevices can result in a serious impact on the work done per cycle, fuel conversion efficiency, and pollutant emission, which are all important in the firing cycle. In the present work, first a Polytropic-Based Blowby Model (PBBM) was validated using a Thermodynamic Simulation Code (TSC) equipped with a blowby sub-model. Then, using the experimental results extracted from a single-cylinder SI research engine in skip-fire and NG fuel mode, the P − θ of an Ensemble Average Cycle (EAC) was calculated from the P −θs of 200 experimental cycles. The crevice flow rates of the EAC were estimated using TSC and PBBM. The results showed a good agreement between them. The study of blowby in 200 experimental cycles via the use of PBBM revealed that the existing cyclic variations of the cylinder pressure caused corresponding cyclic changes in Net Cylinder Mass Lost (NCML) and Net Mass Passed (NMP) through the ring orifices and the pressure inside the crevices. A linear correlation was observed between maximum NCML and cylinder peak pressure while an inverse correlation was detected between cylinder peak pressure and NCML at the EVO position. [ABSTRACT FROM AUTHOR]

Compressed Natural Gas (CNG) is an affordable fuel with a higher octane number. However, older CNG kits without electronic controls have the potential to supply more fuel when driving downhill due to the vacuum in the intake manifold. Therefore, this article presents a development of a CNG control system that accommodates road inclination angles to improve fuel efficiency. Machine learning is involved in this work to process engine speed, throttle valve position, and road slope angle. The control system is designed to ensure reduced fuel consumption when the vehicle is operating downhill. The results showed that the control system increases fuel consumption by 25.7% when driving downhill which an inclination of 5?. The AFR increased from 17.5 to 22 and the CNG flow rate decreased from 17.7 liters/min to 13.8 liters/min which is promising for applying to CNG vehicles. [ABSTRACT FROM AUTHOR]

The uncertainty in the supply of crude oil, increasing the number of vehicles and rising air pollution, especially in urban areas, has prompted us to look for alternative fuels. It is understood that using Compressed Natural Gas (CNG) in IC engines could be a mid-term solution to these problems. It is well established that CNG has better combustion characteristics and low emissions compared to conventional gasoline and diesel fuel. In the present study, an experiment was conducted to evaluate the engine performance and exhaust emissions using various percentages of CNG in dual fuel mode. CNG was mixed in the intake manifold's air stream, and diesel was injected after the compression of the CNG air mixture. This paper presents experimental results of 40%,60%, and 80% CNG in the air stream. Engine performance and emissions are presented and discussed at a speed of 1200 rpm to 1500 rpm in steps of 50 rpm. The results of the experiments showed that adding CNG to diesel engines in dual-fuel combustion significantly impacted performance and emissions. Compared to single diesel fuel combustion, dual fuel combustion increases brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC) at all CNG energy shares and engine speeds. Carbon monoxide (CO) and hydrocarbon (HC) emissions were increased, while nitrogen oxide (NOX) and smoke opacity were decreased in dual fuel combustion compared to single diesel fuel. [ABSTRACT FROM AUTHOR]

In this paper, general characteristics related to the supply chain of compressed natural gas (eng. CNG - Compressed Natural Gas) are given. Compressed natural gas is stored in a compressed gas state in tanks (bottles), in contrast to liquefied natural gas (eng. LNG - Liquefied Natural Gas) in which natural gas is stored in liquid form. The production and storage of compressed natural gas is somewhat cheaper compared to liquid natural gas, with the fact that the storage volumes are different. From all of this, there is a need to analyze the supply chain with CNG from the aspect of the compression process, transportation and storage costs. This paper describes the process of exploitation of CNG as a fuel for the conditions of functioning of the supply chain in Bosnia and Herzegovina. Real data related to the process of compression, transportation and storage of natural gas were taken from the company: "Prvo gasno društvo" D.O.O. Zvornik. The paper analyzed the indicators of the chain like energy efficiency, CO2 emissions and production cost reduced per 1 kWh of energy expressed in the lower heat value (LHV) of the distributed fuel. Also, a short comparison of the supply chains by CNG, wood pellets and chips as fuels is presented by the MCDM method. From the aspect of transport logistics, CNG has significantly better predispositions compared to other supply chains of pellets and wood chips, taking into account the energy efficiency of its process as well as the cost of supply logistics itself. However, CNG belongs to the category of fossil fuels. [ABSTRACT FROM AUTHOR]

Copyright of Safety & Fire Technology (2657-8808) is the property of Centrum Naukowo-Badawcze Ochrony Przeciwpozarowej and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Natural gas is one of the potential combustion engine fuels whose proportion in the overall energy balance is expected to increase. Owing to some of its properties, its use requires a dual-fuel supply system; thus, the use of natural gas as a fuel for diesel engines is currently limited. Systems that supply gas fuel to diesel engines do not usually interfere with the engine control system. This solution significantly reduces system-installation costs. However, as demonstrated in the present study, it considerably changes the course of the combustion process, which increases thermal and mechanical loads. In this case, the combustion process can be controlled by changing the liquid fuel injection pressure or advancing the injection angle. This, however, requires interference with the engine control system.