Natural Gas Vehicles Research Articles

Fuel for Inequality: Distributional Effects of Environmental Reforms on Private Transport

This paper provides the first empirical evidence of the distributional effects of subsidies for the purchase of alternative vehicles based on an extended version of Hausman's exact consumer surplus. Consistently with economic theory, we estimate changes in household welfare, inequality and social welfare corresponding to different reforms. First, we find that an additional tax on conventional fuel is regressive. However, returning the additional tax revenue via lump-sum transfers can alleviate this effect. Second, when the additional revenue is also used to finance subsidies for electrical and compressed natural gas (CNG) vehicles, households that own such vehicles experience welfare gains. However, this policy also increases income inequality and decreases social welfare.

Prospects for energy efficiency improvement and reduction of emissions and life cycle costs for natural gas vehicles

This work is devoted to the experimental investigation of the possibilities to reduce greenhouse gas emissions and to increase energy efficiency of engines that use natural gas as the main fuel and the analysis of economic efficiency of use of dual fuel engines in vehicles compared to conventional diesel. The results of experimental investigation of a 190 kW dual-fuel engine are presented; it is shown that quantitative and qualitative working process control may ensure thermal efficiency at the same level as that of the diesel engine and in certain conditions 5...8% higher. The prospects for reduction of greenhouse gas emissions have been assessed. The technical and economic evaluation of use of dual fuel engines in heavy-duty vehicles has been performed, taking into account the total life cycle. It is shown that it is possible to reduce life cycle costs by two times.

Hydrogen Effect Assessment of Fuel Supply Systems for Hydrogen Blended Natural Gas Vehicle

Hydrogen Effect Assessment of Fuel Supply Systems for Hydrogen Blended Natural Gas Vehicle

A thermodynamic analysis of refueling a Natural Gas Vehicle cylinder from a cascade reservoir using chilled natural gas

The aim of this study was to simulate the refueling of a Natural Gas Vehicle (NGV) Cylinder from a Cascade Reservoir using chilled Natural Gas. The model was developed using the First Law of Thermodynamics, Mass balances and Gas Dynamics laws. Three distinct Cascade Reservoir temperatures were selected for simulations for this study; 288 K, 291 K and 293 K respectively. Simulations were conducted employing various initial NGV Cylinder parameters (Temperature and Pressure). The empirical findings from the simulations showed that the use of chilled Natural Gas to refuel an NGV Cylinder resulted in a reduced temperature increase during refueling in the order of 50 K-60 K as opposed to 70 K-80 K when refueling at ambient temperature. It was also observed that when using chilled natural gas to refuel, the initial cylinder temperature had no effect on the overall refueling process. However, varying initial cylinder pressures had a significant effect.Fill ratios obtained using the chilled gas were greater than refueling at ambient, however it was expected that using chilled gas fill ratios would be greater than 80%, this was not observed. The highest fill ratio obtained was 70.13%. Further analysis on the performance of the reservoir temperatures selected showed that the lower reservoir temperatures mitigated the effects of the Heat of Compression during refueling far better than refueling from ambient. This manifested in reduced in-cylinder temperature rise during refueling and higher fill ratios at completion of fill. Therefore, it was concluded that the Reservoir Temperature (Tres) has the greatest effect on the refueling process and lower Reservoir Temperatures are key to obtaining fill ratios >80%. Further study is definitely required into this novel method of obtaining a quality fill with CNG.

How Total is a Total Cost of Ownership?

In this paper a segmented Total Cost of Ownership (TCO) model is presented for alternative vehicle technologies as well as its extension with external costs related to vehicle ownership and use. Adding external costs to the TCO extends the interpretation of individual ownership to a societal perspective by describing the effect of the technologies on the costs for the society. This extension, called “Total Cost for Society”, suggests that battery electric vehicles, plug-in hybrid electric vehicles and hybrid electric vehicles have a lower societal cost than petrol, diesel and compressed natural gas vehicles.

Analysis of valve-retainer orientation influence on a reciprocating compressor for natural gas vehicle refueling stations

In natural gas vehicle refueling stations, the reciprocating compressor is the key element in defining both the refueling process efficiency and the operating costs of the whole station. Great attention is therefore devoted at increasing both the performance and reliability of the machine. The valve-retainer is a component that plays a key role in determining the compressor performance, by introducing significant pressure losses, which affect the suction and discharge phases. However, the valve-retainer is essential for the proper orientation of the valve during the compressor operation and guarantees a simple and reliable design of the machine. Nevertheless, present design guidelines for the valve-retainer are focused mainly on reliability and maintenance criteria, with scarce regard to the fluid-dynamics behavior of this component.In order to assess the influence of the valve-retainer on the performance of a reciprocating compressor for refueling natural gas powered vehicles, attention is given in this study to the retainer orientation that determines the flow path of the process gas inside the compressor plenums. No previous work was found dealing with the assessment of the influence of the valve-retainer geometric features on the fluid-dynamic behavior of the plenum.The present analysis was carried out by taking advantage of a hybrid time-frequency domain numerical model, able to provide a significant increase of the accuracy level and reduced computational costs. The model was also integrated with FEM acoustic and CFD steady-state simulations to characterize the acoustic response of the plenum and the pressure losses, respectively. As a case study, a double acting compressor with two different orientations of the valve-retainer was analyzed by simulating the interaction between the compressor and its plenums. The compressor performance was evaluated in terms of indicated power, specific power, suction and discharge mass flow profiles and pressure oscillations inside the compressor plenums. The robustness and accuracy of the approach allowed one to assess that the influence of the valve-retainer orientation on the compressor performance is indeed negligible. It was observed that a 6% variation of the pressure loss across the plenum between the two configurations led to an absorbed power variation lower than 0.2% and a variation of compressed gas mass lower than 1%.

Pd catalyst supported on ZrO2‐Al2O3 by double‐solvent method for methane oxidation under lean conditions

AbstractThe Pd catalyst supported on the Zr0.5Al0.5O1.75 composite material was prepared by the conventional impregnation and double solvent impregnation method. The effects of preparation method on the catalytic properties of the Pd/Zr0.5Al0.5O1.75 catalyst for methane combustion have been investigated systematically. The measurement was evaluated in a multiple fixed‐bed continuous flow micro‐reactor by passing a gas mixture simulating the exhaust emissions from lean‐burn natural gas vehicles. The as‐prepared catalysts were characterized by CO chemical adsorption, transmission electron microscopy (TEM), hydrogen‐temperature programmed reduction (H2‐TPR),and X‐ray photoelectron spectroscopy (XPS) measurements. The results of TEM and CO chemisorption showed that the introduction of double solvent during the preparation of Pd/Zr0.5Al0.5O1.75 was beneficial for the dispersion of Pd nanoparticles and obtained superior resistance to the sintering of Pd on the surface of Zr0.5Al0.5O1.75. The H2‐TPR measurements demonstrated that the double solvent method increased the reducibility of the Pd catalyst. The XPS results further indicated that more active surface oxygen species also can be formed on the catalyst prepared via double solvent process. Thus, this catalyst exhibited better catalytic performance and hydrothermal aging resistance in the methane oxidation compared to its analogues with the same Pd content prepared by the conventional impregnation method.

Design of a Solenoid Actuator for a Cylinder Valve in a Fuel Cell Vehicle

Green vehicles include electric vehicles, natural gas vehicles, fuel cell vehicles (FCV), and vehicles running on fuel such as a biodiesel or an ethanol blend. An FCV is equipped with a cylinder valve installed in an ultra-high pressure vessel to control the hydrogen flow. For this purpose, an optimum design of the solenoid actuator is necessary to ensure reliability when driving an FCV. In this study, an electromagnetic field analysis for ensuring reliable operation of the solenoid actuator was conducted by using Maxwell V15. The electromagnetic field analysis was performed by magneto static technique, according to the distance between magnetic poles, in order to predict the attraction force. Finally, the attraction force was validated through comparison between the Maxwell results and measurement results. From the results, the error of attraction force ranged from 2.33 to 3.85 N at testing conditions.

Passenger vehicles that minimize the costs of ownership and environmental damages in the Indian market

Rapid expansion of population and income growth in developing countries, such as India, is increasing the demand for many goods and services, including four-wheeled passenger cars. Passenger cars provide personal mobility; however, they also have negative implications for human wellbeing from increased air pollutants and greenhouse gases (GHG). Here, we evaluate the range of passenger vehicles available in the Indian market to identify options that minimize costs, human health effects and climate damages. Our approach is to compare alternative fuel/powertrain vehicles with similar conventional gasoline fueled vehicles and assess the differences in full (private and societal) costs for each pair. Private costs are the combination of capital costs and the discounted expected future fuel costs over the vehicle lifetime. The costs to human health from air quality are calculated using intake fractions to estimate exposure and literature values for the damage costs adjusted by benefits transfer methods. We use the Social Cost of Carbon to estimate climate damages. We find that, on average, the net present value (NPV) of the full costs of compressed natural gas (CNG) vehicles are lower than comparable gasoline vehicles, while, diesel vehicles have higher costs. Presently, electric vehicles have higher private costs (due to high capital costs) and societal costs (due to electricity generation emissions). Either a less carbon intensive electricity grid or an increase in the CNG fleet would minimize total costs, human health effects and GHG emissions from the passenger vehicle fleet. Policy makers should consider promoting the use of CNG vehicles, although this would require supporting infrastructure improvements.

Deactivation Aspects of Methane Oxidation Catalysts Based on Palladium and ZSM-5

Catalytic methane oxidation is used in exhaust gas after treatment to reduce methane emissions in stationary combustion processes as well as in natural gas vehicles. Pd/zeolite catalysts provide higher activity than the commonly used Pd/Al2O3, but suffer from rapid deactivation under reaction conditions and in the presence of steam. This work presents a detailed study of deactivation of 1 wt% Pd/H–ZSM-5 catalyst in reaction conditions in dry and wet feed including characterization of both the active phase and the support. Initially well-dispersed PdO particles are not stable and sinter immediately after the exposure to the reaction mixture even in dry feed and stabilize at lower dispersion level. Despite the reasonable methane oxidation activity exhibited by the large particles, the initial PdO particles could potentially provide a 40 °C lower methane oxidation temperature. In the presence of water in the feed at moderate temperature (450 °C), support degradation governs the deactivation of the catalyst, which is evidenced by a significant decrease in BET surface area and generation of extra-framework aluminium species. These results suggest that active and stable catalysts could be obtained by careful choice and design of the support material with the aim to guarantee high dispersion of PdO.

A stakeholder analysis of the automotive industry's use of compressed natural gas in Nigeria

Nigeria experiences a perennial shortage of transportation energy despite being the world’s eighth largest producer of crude oil and the seventh largest proven reservoir of natural gas. Partly as a result, the Nigerian government proposed the use of compressed natural gas (CNG) as an automotive fuel in 1997 as part of the efforts to harness the country’s natural gas resources and address transportation energy challenges. However, the rate of adoption has been very low with natural gas vehicles constituting 0.04% of the national vehicle fleet. This paper presents a stakeholder analysis derived from interviews with senior executives of the leading organisations involved in the energy and transportation sectors in Nigeria. Analysis revealed thirty-one barriers and twenty-six policy proposals that were categorised into eight and four themes respectively. While there is a rarity of agreement across all stakeholder groups, we observed consensus on the suggestion for the removal of the subsidy on petrol and the need for the establishment of a coordinating agency to drive the use of CNG. The paper offers specific recommendations for the reform of the energy and transportation sectors, the introduction of fiscal and operational incentives and the creation of public awareness.

Portfolio analysis of alternative fuel vehicles considering technological advancement, energy security and policy

In recent years, there has been an increasing interest in alternative fuel vehicles (AFVs), such as electric vehicles (EVs), fuel cell vehicles (FCVs) and compressed natural gas (CNG) vehicles, as a promising option for mitigating global warming and reducing energy consumption. Most studies in this area have been conducted on only a few types of powertrains, e.g. EVs and gasoline vehicles; to fill this gap, this study will cover FCVs, CNGs, hybrid electric vehicles, diesel hybrid electric vehicles and liquefied petroleum gas (LPG) vehicles. This research is novel because it includes energy security aspects, uses scenario analysis and investigates FCVs. This study aims to predict an optimal AFV portfolio based on different scenarios to sustain energy security in light of gas and petroleum restrictions until 2030. To do this, we will present four scenarios that consider improvements in technology, energy security requirements, decreasing petroleum prices and government subsidies. The Polish market is considered as a case for demonstrating the optimal model. The results indicate that it is crucial to introduce all types of powertrains to achieve both economic and energy security objectives. The projected diffusion of FCVs will be more pronounced than that in previous studies, owing to the expected rapid decline in the cost of both infrastructure and purchase price of cars. Furthermore, the projected deployment of AFVs in transportation systems in this study will mostly occur in the form of lorries (trucks) and passenger vehicles. Because CNG vehicles are expected to achieve a high degree of diffusion in the transportation system, the government should seek a reliable CNG supply. Overall, this research will help automakers and policymakers recognise investment possibilities.

Prospects of and Problems in Using Natural Gas for Motor Transport in RUSSIA

This article is devoted to increasing the use of natural gas in Russia as a measure to decrease the negative influence of motor transport on the environment. A brief analysis of the global fleet of natural gas vehicles is provided above. The documents accepted in Russia to promote public awareness of compressed natural gas in transport are submitted. The basic reasons keeping the growth of natural gas vehicle fleets in Russia consist of weak branching of refuelling stations; difficulty in determining the actual amount of compressed natural gas required; and control methods of the consumption of gas fuel. The offers promoting the growth of the fleet of natural gas vehicles are given.

An evaluation of speed management measures in Bangladesh based upon alternative accident recording, speed measurements, and DOCTOR traffic conflict observations

With 21,000 people annually killed in road traffic (estimated figure by World Health Organization), Bangladesh has one of the highest fatality rates in the world. Vulnerable road users (VRUs) account for over 50% of road traffic casualties, and 70% of casualties occur in rural areas. As in many Low and Middle Income Countries (LMICs), the official road accident statistics are incomplete and biased.Safe Crossings (Netherlands) and the Centre for Injury Prevention and Research Bangladesh (CIPRB) (Bangladesh) received permission from the Bangladesh government in 2014 to design and implement an integrated speed management program (consisting of a combination of small-scale infrastructural measures, active community involvement and road user education) at three locations where a national highway intersects small communities. The infrastructural countermeasures to improve road safety consisted of speed humps, rumble strips, signs and road markings and were designed following the Dutch road design guidelines. In a Before–After study design, we used a combination of three research methods to monitor and evaluate the road safety interventions. We created our own traffic accident recording system with trained local record keepers, we conducted laser-gun speed measurements of motorized traffic (both at intervention and control locations), and we applied the Dutch Objective Conflict Technique for Operation and Research (DOCTOR) for observing serious traffic conflicts at the intervention locations. The latter was based upon DOCTOR scores from video recordings of the behaviour at the three experimental locations Before and After the interventions.Prior to installing the intervention program, the three locations combined had, on average, about 100 serious accidents, 10 deaths, and 200 injured people on a yearly basis. In April 2015, all infrastructural measures were completed. In the after period (till the end of January 2016), the alternative accident recording system showed a 66% reduction in the number of serious accidents, a 73% reduction in the number of injured people, and a 67% reduction in the number of people killed.The unobtrusive laser-gun speed measurements resulted in a net reduction of 13.3km/h (or 20% in relative terms) on average at the intervention locations by taking the general speed development at the control locations into account. According to Nilsson’s power law this would result in a 59% reduction of the number of people killed, well in line with the actual accident figures.The total number of serious conflicts (only DOCTOR scores 3, 4, and 5) was significantly reduced from 64 serious conflicts per location in a 4.5h period Before to 29 serious conflicts in the After period, on average (Poisson distributed variable, p<0.01), or a 55% reduction in relative terms. By including the traffic volumes, the reduction in conflict risk overall is 54%. Moreover, the severity of conflicts was reduced in the After period with only one most severe conflict (DOCTOR score 5) left. Buses represent the largest portion of road users involved in serious conflicts at all three locations, followed by cars and CNGs (Compressed Natural Gas vehicle). By far, the most frequently occurring conflict is of the type head-on conflict between an overtaking bus or car that is encountering a road user in opposite direction (for the greater part a CNG).All three evaluation measures point to a similar impact of the intervention program and unveil an improvement in road safety between 54% and 60%. The speed-reducing measures indeed considerably reduce the speed of motorized traffic, both the mean speed and 85th percentile values, both the number and severity of serious conflicts are reduced, and the actual number of accidents has decreased. It appears that Nilsson’s power law for the relation between a difference in mean speed and the change in the number of accidents also applies to LMICs.Speed management measures as common in high-income countries appear to be also effective in LMICs. For evaluation purposes of road safety impacts, a Traffic Conflicts Technique approach (also developed in high-income countries) seems valid and effective as well for application in LMICs.As there are thousands of traffic black spots with similar characteristics as the three intervention locations in Bangladesh, this integrated approach may well offer similar road safety improvements elsewhere.

Using agent-based modeling to explore policy options supporting adoption of natural gas vehicles in Indonesia

The diffusion of Natural Gas Vehicles (NGVs) has been slow although the government has already developed infrastructures and regulations to enable the uptake. This paper attempts to understand the consumers’ adoption decision-making and to explore potential policy interventions favoring the uptake. Two models are compared: a non-psychological model and a psychological model. Using Agent-based Social Simulation, the psychological model was found to offer a better explanation for underlying mechanisms of the adoption decision. The results indicate that individual interventions largely fail to induce long-term NGV diffusion. To promote a sustaining market share of NGVs at 14% in 2030, a combined intervention should be introduced that includes: a converter kit subsidy of 5 M Rupiah for five years, a gradual increase of annual tax for oil-fueled vehicles to 2.5% in 2030, increased perceived safety of NGVs to the same level as that of Low Cost Green Cars, and additional gas fueling stations.

구조 안전성을 고려한 수소 연료 전지차 용기 밸브의 솔레노이드 액추에이터 설계

Green vehicles include electric vehicles, natural gas vehicles, fuel cell vehicles (FCV), and vehicles running on fuel such as a biodiesel or an ethanol blend. An FCV is equipped with a cylinder valve installed in an ultra-high pressure vessel to control the hydrogen flow. For this purpose, an optimum design of the solenoid actuator is necessary to ensure reliability when driving an FCV. In this study, an electromagnetic field analysis for ensuring reliable operation of the solenoid actuator was conducted by using Maxwell V15. The electromagnetic field analysis was performed by magnetostatic technique, according to the distance between magnetic poles in order to predict the attraction force. Finally, the attraction force was validated through comparison between the Maxwell results and measurement results. From the results, the error of attraction force ranged from 4.53 % to 9.05 % at testing conditions.

Adoption of Natural Gas Vehicles – Estimates for the U.S. and the State of Texas

Natural gas vehicles (NGV) have attracted more and more attention from policy makers since natural gas is a clean substitute for traditional fossil fuel that is also readily accessible. In some areas such as the state of Texas, vehicles that do not use traditional fossil fuel (e.g., NGVs) are exempt from paying fuel taxes. Government financial incentives have motivated substantial adoption of NGVs. This paper studies NGV adoption behavior in both U.S. and Texas markets to estimate the dynamics of NGV diffusion. This research employs well-known Bass diffusion models applied to NGV adoption, using data from both the U.S. and Texas. Among several interesting results, we find that NGV adoption through an imitation effect appears to be significant for the U.S. NGV market.

Gaseous emissions from compressed natural gas buses in urban road and highway tests in China

The natural gas vehicle market is rapidly developing throughout the world, and the majority of such vehicles operate on compressed natural gas (CNG). However, most studies on the emission characteristics of CNG vehicles rely on laboratory chassis dynamometer measurements, which do not accurately represent actual road driving conditions. To further investigate the emission characteristics of CNG vehicles, two CNG city buses and two CNG coaches were tested on public urban roads and highway sections. Our results show that when speeds of 0–10km/hr were increased to 10–20km/hr, the CO2, CO, nitrogen oxide (NOx), and total hydrocarbon (THC) emission factors decreased by (71.6±4.3)%, (65.6±9.5)%, (64.9±9.2)% and (67.8±0.3)%, respectively. In this study, The Beijing city buses with stricter emission standards (Euro IV) did not have lower emission factors than the Chongqing coaches with Euro II emission standards. Both the higher emission factors at 0–10km/hr speeds and the higher percentage of driving in the low-speed regime during the entire road cycle may have contributed to the higher CO2 and CO emission factors of these city buses. Additionally, compared with the emission factors produced in the urban road tests, the CO emission factors of the CNG buses in highway tests decreased the most (by 83.2%), followed by the THC emission factors, which decreased by 67.1%.

Research on the theory and application of adsorbed natural gas used in new energy vehicles: A review

Natural gas, whose primary constituent is methane, has been considered a convincing alternative for the growth of the energy supply worldwide. Adsorbed natural gas (ANG), the most promising methane storage method, has been an active field of study in the past two decades. ANG constitutes a safe and low-cost way to store methane for natural gas vehicles at an acceptable energy density while working at substantially low pressures (3.5–4.0 MPa), allowing for conformable store tank. This work serves to review the state-of-the-art development reported in the scientific literature on adsorbents, adsorption theories, ANG conformable tanks, and related technologies on ANG vehicles. Patent literature has also been searched and discussed. The review aims at illustrating both achievements and problems of the ANG technologies- based vehicles, as well as forecasting the development trends and critical issues to be resolved of these technologies.

Performance improvement of liquefied natural gas (LNG) engine through intake air supply

To improve the natural gas vehicle accelerating and climbing performance, the approach of intake air supply for LNG engine was proposed and then investigated. A set of intake air supply device was designed and coupled to a LNG engine. Then, the bench test of intake air supply for LNG engine was conducted under both transient and steady state conditions, and the performance of LNG engine with intake air supply was compared with the original engine. The results indicate that engine torque can be improved obviously at low-speed, while the specific gas consumption (SGC) is almost unchanged with intake air supply. At 1000r/min, the torque can be increased by 31%, and the SGC is decreased by 1.64%. Based on the test results, the optimal injection pressure of supplied air at various speeds was determined. Finally, the vehicle test of intake air supply was also conducted under road conditions. Compared with the original natural gas vehicle, the acceleration time is decreased by 14.7–30% through intake air supply, and the higher gear ratio contributes to the better acceleration performance. Meanwhile, the response time of intake pressure can be decreased by 23.6–67.7%.