Natural Gas Vehicles Research Articles

Anchoring Pt-doped PdO nanoparticles on γ-Al2O3 with highly dispersed La sites to create a methane oxidation catalyst

Catalysts for the complete oxidation of methane suffer from poor physical and chemical stability regarding their noble metal active sites. Herein, we prepared a PtPd-La1/Al2O3 catalyst by loading highly dispersed La species and Pt-PdO nanoparticles on γ-Al2O3 support, exhibiting significantly enhanced hydrothermal and long-term stability under the harsh conditions of simulated natural gas vehicle (NGV) exhaust. Over PtPd-La1/Al2O3, PdO nanoparticles (NPs) can be anchored by highly dispersed La sites through electron transfer from La to PdO, inhibiting the sintering of Pd species during hydrothermal aging. Pt uniformly doped in PdO creates high-efficiency Pt sites and unsaturated Pd sites (as well as Pd sites adjacent to O defects) for water-resistance, further enhancing long-term stability. Thus, this work provides the potential to resolve tough challenges related to methane emission control on NGVs.

Real driving emissions of Euro 6 electric/gasoline hybrid and natural gas vehicles

Electric hybrid powertrain and natural gas fuel for spark-ignition engines are among the much promising technologies to reduce the fossil fuel use for road transportation and the emissions of harmful and greenhouse gases. This paper investigated gas and particulate real emissions of hybrid and natural gas passenger cars. On road testing were carried out along urban, rural and motorway routes in Napoli (Italy), by using portable emissions measurement systems. Hybrid vehicle has the main advantage of fuel saving in urban environment due to large use of pure electric mode operation at low speed and load. On the other hand, continuous engine restarting causes peak emissions due to a longer light-off time of aftertreatment systems. By analysing the Vehicle Specific Power, it was observed that at same positive values of power, natural gas vehicle is characterized by lower emission and fuel/energy consumption rates compared to the hybrid vehicle.

Green Methane as a Future Fuel for Light-Duty Vehicles

Food waste (FW) has traditionally been disposed by incineration or landfilling; however, it can be converted to green methane (GM) via anaerobic digestion, and GM can be used as fuel for light-duty natural gas vehicles (LDNGVs). A lifecycle assessment (LCA) of FW-based GM production and LDNGV operation in China, a new scenario, was performed. The LCA results were compared with those for the conventional FW treatment, where a “well-to-wheel” system boundary including FW collection, GM production from FW, and vehicle manufacturing, operation, and disposal was defined. The LCA results showed that the global warming impacts of the new FW scenario are 44.3% lower than those of the conventional option. The fine particulate matter formation impact of the new FW scenario was dominated by the displacement effect of electricity supply to anaerobic digestion, followed by CO2 adsorption by the primary source. The sensitivity analysis showed that hydroelectric power as the best primary source for electricity supply could substantially reduce both global warming and FRS in the new scenario. In the short term, the proposed FW scenario could be a feasible option for achieving sustainable society by minimizing environmental impacts of FW treatment.

Novel short-term national strategies to promote the use of renewable hydrogen in road transport: A life cycle assessment of passenger car fleets partially fuelled with hydrogen

This work presents an energy analysis combined with a comparative environmental life cycle assessment (LCA) of eight different passenger car fleets that use renewable hydrogen and a conventional fuel (natural gas or gasoline) under the same total energy input and the same hydrogen-to-mixture energy ratio. The fleets under comparison involve vehicles that use the two fuels separately or in a mixture. Using Italy as an illustrative country, this research work aims to help policy-makers implement well-supported strategies to promote the use of hydrogen in road transport in the short term. The proposed strategies achieve a carbon footprint reduction between 7 % and 35 % with respect to their conventional fleet benchmark. Within the current context, the results suggest the energy and environmental suitability of using hydrogen blends as short-term solutions, involving vehicles that require minor modifications with respect to current compressed natural gas vehicles and gasoline vehicles, while paving the way for pure hydrogen mobility.

Coordinated bidding of multi-product charging station in electricity markets using rolling planning and sample average approximation

Recently, there has been an urgent tendency to steer the transport system towards zero-emission. Along natural gas vehicles, electric and hydrogen vehicles represent a promising way to a low-carbon system. Since the development of these vehicles relies on advances of refueling stations, their economic and operational aspects need to be considered. Therefore, this paper addresses a multi-product charging station for refilling electric, hydrogen and natural gas vehicles. The station participates in day-ahead and intra-day markets where the market price is subject to the uncertainty. For charging station participating in sequential markets with different prices, it is necessary to consider the coordinated bidding. Taking into account the sequential clearing of these markets and the gradual realization of market prices, the bidding problem is formulated as a two-stage stochastic program. In order to solve this large-scale stochastic program with a huge number of scenarios, the rolling planning method in combination with sample average approximation and SCENRED tool are applied. The study aims to attain the optimal operation of devices and bidding curves of the charging station in order to maximize its profit. The obtained average optimality gap based on Monte Carlo sampling approach, which is less than 1%, proves the effectiveness of our proposed algorithm in solving this large scale stochastic optimization. The submitted bidding curves to the intra-day market are found to be dependent on changes in the day-ahead market prices. Tornado diagrams indicate that the selling price and demand of electricity are ranked as the most effective factors on profit.

Flexible type end restraint to CNG cylinders for NGV

CNG (Compressed natural gas) fuel recently growing due to more efficient as compared to Gasoline & Diesel by vehicle running cost in both passenger as well as commercial vehicles, additionally it is more environment friendly fuel with respect to gasoline & diesel. For using of CNG as a fuel in automobile sector its need a pressure vessel which store the CNG at high pressure which called a CNG cylinder. Since CNG cylinders store CNG at a very high pressure, so design of CNG cylinders, its material, processes to manufacture the cylinders, secure fastening of these cylinders with vehicle chassis & stringent regulatory requirement play a very crucial role for CNG cylinder for NGVs (Natural gas vehicles).There are numerous testing & validations to check stringent requirement of CNG cylinders & secure fastening establishment with vehicle chassis. As per fastening aspect the CNG cylinder should not be separated with vehicle chassis to 20 times of the mass of full CNG cylinder. Through this technical paper author is trying to introduce the CNG cylinder fastening provision along its axis (end to end restrains) through a flexible type high strength polyester belt in place of rigid type end restraint.

Comparison of CO2, NOx, and VOCs emissions between CNG and E10 fueled light-duty vehicles

In China, natural gas (NG) is the main vehicle fuel after gasoline and diesel, and the number of NG vehicles ranks first in the world. At present, there are many studies on the conventional gaseous pollutants and particulate matter of NG vehicles, but very few studies on their VOCs. In this study, the chassis dynamometer is used to test CNG/E10 bi-fuel light-duty vehicles, analyze the advantages of CNG in CO2, fuel thermal efficiency, and cost, and discuss its disadvantages in NOx emission. Most importantly, the emission characteristics and ozone formation potential of VOCs in the exhaust of CNG vehicles were analyzed in the study. Compared with E10, CNG fuel can reduce CO2 emission by about 20 %, improve thermal efficiency by about 13 %, and save fuel costs by about 50 %. However, it will increase NOx and NO2 emissions by about 10 % and 13 % respectively. As for VOCs, the emission factor of VOCs from CNG fuel is about 54 % of E10 fuel. The VOCs group with the highest proportion in the exhaust of CNG-fueled vehicles is alkanes, >80 %. while the alkanes and alkenes with the highest proportion in E10 fuel are 30 % and 23 % respectively. C2 VOCs emitted by CNG account for >70 %, while C2 VOCs emitted by E10 are <60 %, followed by C4 VOCs, about 10 % - 30 %. The OFPs of VOCs in CNG exhaust is about 13.7 % of E10. Alkenes contribute the most to ozone, and the OFPs of alkenes in CNG and E10 vehicle exhaust accounts for about 55.3 % and 78.8 % of TVOCs respectively. The results of this study are helpful to improve people's understanding of the environmental value of using NG vehicles.

Comparative study on monthly natural gas vehicle fuel consumption and industrial consumption using multi-hybrid forecast models

Accurate natural gas consumption forecasting plays a significant role in production, supply, and dispatching. Therefore, in this study, a new multi-hybrid model methodology is proposed that combines both statistical and deep learning models to obtain better prediction results beyond individual models or constrained hybrid models in linear and non-linear modeling. Here, long-term natural gas consumption future forecast analyzes were performed for the USA natural gas vehicle fuel (NG-VFC) dataset from January 1997 to October 2021 and for the USA natural gas industrial consumption (NG-IC) dataset between January 2001 and October 2021.The values obtained as a result of the analyzes using multi-hybrid models based on statistical and deep learning models were evaluated with popular metric values such as mean absolute percentage error and mean absolute scaled error within reference measures. In all analyzes using NG-VFC and NG-IC time series, the best MAPE values were obtained as 5.40% and 3.19% for afnt (equi-weighted) and af (CV-weighted) multi-hybrid models, respectively. While the first of the equi-weighted and CV-weighted approaches featured here required less computation time, the latter required more computation time. In terms of prediction accuracy, the suggested multi-hybrid model outperforms most existing state-of-the-art approaches without sacrificing time or memory complexity.

Prediction of First Ply Failure of Composite Pressure Vessels Under Internal Pressure: A review

Composite pressure vessels (i.e. types III and IV) are widely used for compressed natural gas (CNG) vehicles, as storage cylinders to reduce the weight while maintaining high mechanical properties. These vessels can achieve 70-80% of weight saving, as compared to steel vessels (type I). So, prediction of first ply failure and burst pressure of these vessels is of great concern. Thus, this paper involved a review of literature regarding the first ply failure and burst pressure of composite pressure vessels (types III and IV). The review included the researches related to the simulation, mathematical modeling, and experimental analysis. The study focused on simulation-related research more than others due to the complexities of mathematical modeling of such problems in addition to the high cost of experimental tests. The results indicated that the stacking sequence of layers, vessel thickness and the type of selected composites were the main factors that mainly affect the vessel burst pressure performance. Accordingly, the optimization in the vessel structure (composite fabric architecture) parameters plays an important role in the performance of burst pressure. This in turn will lead to a high vessel durability, longer life-time and better prediction of burst pressure. Furthermore, the study showed that the prediction of first ply failure is more important than burst pressure knowledge of pressure vessels because it gives an initial prediction of vessel failure before the final failure occurrence. This in turn, may prevent the catastrophic damage of vessel.

Environmental and Economical Evaluation of Liquified Natural Gas Vehicles Promotion Program in The City of Baghdad

Environmental and Economical Evaluation of Liquified Natural Gas Vehicles Promotion Program in The City of Baghdad

Significant Reduction of the Formation of N2O and NH3 on an Efficient Three-Way PtRh Catalyst Modified by LaFeCu Perovskite

This work designed a series of three-way catalysts (TWCs) with and without the modification by La0.67Fe0.83Cu0.17O3 (LaFeCu) perovskite to reduce the formation of N2O and NH3 emissions from natural gas vehicles (NGVs). The modified PtRh catalyst was found to have an efficient TWC performance and to reduce the formation of N2O and NH3 significantly. The X-ray diffraction and CO-Fourier transform infrared results demonstrated the formation of Rhx species, which would reduce the formation of NCO*, the main precursor of NH3. In situ diffuse reflectance infrared Fourier transform spectroscopy was used to confirm that no NCO* groups were found on the modified catalyst. The X-ray photoelectron spectroscopy results revealed the increase in the Pt2+ content on the modified catalyst, promoting the decomposition of N2O. Also note that the modified catalyst produced far fewer N2O than the catalyst without modification in the model reaction of CO + NO. Our work would provide a solution to develop an advanced TWC for NGVs.

System dynamics-based assessment of novel transport options adoption in India.

The adoption of novel transport options such as ethanol blended fuel (E85) vehicles, electric vehicles (EV), and compressed natural gas (CNG) vehicles to replace conventional petrol (gasoline) and diesel vehicles is not yet well understood. This work develops a system dynamics (SD) model to study the adoption of these novel options for private transport needs in India as a function of technology performance, cost, and other sector specific features. For EVs, expected growth in battery technology and the inconvenience due to lack of charging infrastructure are considered. Since ethanol production sector is still scaling up, model captures the inter-relationships between demand, supply, producer’s profit, and investment in capacity increase. The growth in compressed biogas (CBG) plants and inconvenience due to lack of gas refilling stations are considered for CNG vehicles. For petrol and diesel, the effect of demand on consumer prices and its effect on ownership cost is modelled. A multi-multinominal logit model is used to capture selection of transport option as a function of total ownership costs. Model simulations are performed till 2050, and quantify the adoption trends as well as resulting total greenhouse gas emissions considering life cycle perspective for all the technological options. Simulation results show that E85, EVs and CNG vehicles would constitute 34 % of total private vehicle stock by 2050, resulting in 668.75 million tonnes of CO_2 emissions. The targets set by the government for EV adoption and blending rate of ethanol will not be achieved, and significant improvement is costs and infrastructure are needed. Various policy options to improve adoption of new options are explored, identifying the technology development targets.Graphic abstract Supplementary InformationThe online version contains supplementary material available at 10.1007/s10098-022-02398-8.

The logistics route of a CNGV distribution station and operation simulation: SRM Bucharest refueling station

This article aims to simulate natural gas vehicle (NGVs) refueling station located in Bucharest, which includes an on-board cylinder, reservoir tanks, connecting pipes, and a reciprocating compressor using thermodynamic analysis. Tanks’ pressures during the filling process were changed: 180-200, 200-220, and 220-235 bar for low, average and high pressure respectively. Furthermore, sensitivity analyses were implemented to study changing the cylinder initial pressure and the influence of vehicles’ number alteration. The simulation result for mass flow rate is close to the experimental measurements. Additionally, the higher the initial pressure inside vehicle tank, the lower mass delivered and the shorter loading time. Finally, this study helps the government to increase the environmentally friendly fuel in the local market.

Coordinated Planning of Electric Power and Natural Gas Distribution Systems With Refueling Stations for Alternative Fuel Vehicles in Transportation System

The alternative fuel vehicles (AFVs) which include electric vehicles (EVs) and natural gas vehicles (GVs) have gained much attention in recent years for delivering a clean and low-carbon urban mobility. The AFV development is promoting the coordination among electric power, natural gas, and transportation (ENT) networks. This paper proposes a coordinated planning method for investment on and operation of emerging urban energy infrastructures. The sites and sizes of refueling stations are optimized along with the expansion strategies for electric power distribution network (PDN) and natural gas distribution network (GDN). First, AFV refueling demands are analyzed according to the refueling station constraints and options, and transportation network (TN) constraints. Second, the coordinated planning model for PDN and GDN is formulated along with respective operation constraints in PDN, GDN, and TN. An efficient MILP solution method is developed for the proposed optimization problem. Finally, several case studies verify the effectiveness of the proposed model and its solution method. Compared with existing solutions, the proposed panning method offers a more accurate AFV refueling demand model with various refueling options. It is demonstrated that the coordinated planning can reduce investment and operation costs of urban energy infrastructures by exploring the pertinent interactions among constrained PDN, GDN, and TN.

Investigation of the evolution of Pd-Pt supported on ceria for dry and wet methane oxidation

Efficiently treating methane emissions in transportation remains a challenge. Here, we investigate palladium and platinum mono- and bimetallic ceria-supported catalysts synthesized by mechanical milling and by traditional impregnation for methane total oxidation under dry and wet conditions, reproducing those present in the exhaust of natural gas vehicles. By applying a toolkit of in situ synchrotron techniques (X-ray diffraction, X-ray absorption and ambient pressure photoelectron spectroscopies), together with transmission electron microscopy, we show that the synthesis method greatly influences the interaction and structure at the nanoscale. Our results reveal that the components of milled catalysts have a higher ability to transform metallic Pd into Pd oxide species strongly interacting with the support, and achieve a modulated PdO/Pd ratio than traditionally-synthesized catalysts. We demonstrate that the unique structures attained by milling are key for the catalytic activity and correlate with higher methane conversion and longer stability in the wet feed.

Life cycle assessment on energy efficiency of hydrogen fuel cell vehicle in China

Based on the analysis and research achievements of domestic and foreign scholars regarding the vehicle life cycle assessment, in combination with the research data of relevant enterprises, the research has objectively assessed well to wheel energy efficiency of hydrogen fuel cell vehicle, and performed comparative analysis with conventional gasoline vehicle, conventional diesel vehicle, natural gas vehicle, methanol vehicle and battery electric vehicle. The research results show that the range of well to wheel energy efficiency of hydrogen fuel cell vehicle is between 6.8% and 29.2%, which depend much on the difference of source and transport mode of hydrogen, and the range covers several technical routes of vehicles other than battery electric vehicle which uses green electricity. The well to wheel energy efficiency under the scenario of hydrogen production from water electrolysis using renewable power such as photovoltaic and wind power is relatively high (21.9%–29.2%). The scenarios of hydrogen from methanol and grid power electrolysis are lower than other scenarios (6.8%–12.5%). The choice of hydrogen transportation mode is closely related to the distance between the production and use sites. For short and medium-distance, long-tube trailers can be used to transport gas hydrogen, and in the case of long-distance transportation, such as more than 800 km, the use of liquefaction or pipeline transportation can better ensure the energy efficiency advantage of hydrogen fuel cell vehicle. Nevertheless, for the same transport distance, the energy efficiency of well to wheel can be improved less effectively by increasing the hydrogen transportation capacity, and more effectively by improving the energy efficiency of the vehicle operation, the feedstock production and the hydrogen production.

Combined theoretical and experimental kinetic approach for methane conversion on model supported Pd/La0.7MnO3 NGV catalyst: Sensitivity to inlet gas composition and consequence on the Pd-support interface

New insights into reaction mechanism for catalytic methane combustion are provided in broad operating conditions on Pd/La0.7MnO3 as model natural gas vehicle catalyst. Under lean and dry conditions, a dual mechanism is suggested with active sites combining reactive oxygen species from La0.7MnO3 and palladium instead of single site reaction mechanism. Aging in wet atmosphere has no consequence on the kinetic behavior. On the other hand, in wet atmosphere near the stoichiometry, strong accumulation of hydroxyl groups on the support would suppress the metal-support interface. Accordingly, methane combustion would take place only on Pd particles.

Influencing factors of trucking companies willingness to shift to alternative fuel vehicles

Freight transportation is a manifestation of a vibrant economy, but it is also associated with negative externalities such as greenhouse gas emissions. To mitigate these impacts, freight vehicles using alternative fuels have been developed, but they are not widely adopted. Moreover, there is not much information on the factors that could incentivize trucking companies to adopt such vehicles, especially in emerging economies where diesel engines dominate the market. Using Colombia as a case study, this paper aims to evaluate the factors that influence businesses to shift towards acquiring trucks powered by alternative fuels, applying an econometric approach based on discrete choice models. Results suggest that demand for alternative fuel vehicles (AFVs) is highly sensitive to purchase costs, operational range, and environmental awareness. Hybrid fuel alternatives seem to be preferred over electric and compressed natural gas vehicles. The analysis is supplemented with the estimation of marginal substitution rates, elasticities, and the simulation of scenarios considering subsidies and tax exemptions, from which we identify implications and draw policy recommendations to promote the use of AFVs.

Natural gas as a vehicular fuel in Brazil: Barriers and lessons to learn

This study aims to analyze the adoption and growth of light-duty natural gas vehicles in Brazil and observe how state incentives and taxes impacted the development of this market at the state level. Brazil's light-duty natural gas vehicles market has slowed its growth considerably since the states with the largest share in the country, Rio de Janeiro and São Paulo, have diverged in the progress of natural gas vehicles. To clarify what led to this scenario, we selected and explored seven parameters: i) availability of natural gas distribution network; ii) the number of certified conversion garages; iii) historic compressed natural gas fuel prices; iv) state value-added taxes; v) motor vehicle property taxes; vi) vehicle-to-refueling-station index and; vii) payback period. In conclusion, it was found that state market incentives are fundamental for the continuous development of alternative fuels such as natural gas to the already established liquid fuels in the country. In Rio de Janeiro, the advantages obtained through tax incentives to compressed natural gas and motor vehicle property taxes are crucial to decrease payback time and strengthen the price of natural gas. Otherwise, in the state of São Paulo, the lowest state value-added tax levied on hydrated ethanol and, consequently, the smallest price difference between fuels hinders the development of the compressed natural gas market.

Integrated artificial intelligence and life cycle assessment to predict environmental and economic impacts for natural gas hybrid electric vehicle with multi-dimension

The automotive industry plays very significant role in Chinese industry. but higher energy consumption and higher pollution accompanying with the vehicle’s industry chain as well. natural gas for vehicles has the characteristics of cleanness, economy and reliability. Therefore, the hybrid vehicle with both advantages of natural gas and electricity has great potential. However, it is unclear that the promotion of natural gas / electric hybrid vehicles (NGEHV) could really achieve energy saving and emission reduction. In this paper, consider all stages vehicle production, transportation, use, maintenance and scrap recovery, the possession is decomposed into three aspects: resource attributes, energy attributes and environmental attributes. An composition analysis method of NGEHV is constructed. A life cycle assessment(LCA), in the view of Cradle-to-Grave, of environmental impact for natural gas / electric hybrid vehicles is established. Based on BP neural network, prediction information of traditional vehicles and NGEHV on various environmental factors and costs are obtained. It could provide scientific basis for the sustainable advancement and decision-making for government.