Fuel Control System on CNG Fueled Vehicles using Machine Learning: A Case Study on the Downhill

<div class="htmlview paragraph">The usage of Compressed Natural Gas (CNG) engines is increasing as requirements for cleaner emissions are required by state and federal agencies such as C.A.R.B. and E.P.A. Also, to further reduce emission levels, tighter air/fuel ratio control is required.</div> <div class="htmlview paragraph">There are many ways to control air/fuel ratio on a CNG engine. It can be performed in a feedforward method, a feedback method or a combination of both. CNG fuel can be introduced to the engine via single-point injection, multi-point injection or with an air/gas mixer. Mixer-type and single-point injection are good candidates for the application of a gas flow sensor for accurate air/fuel ratio measurement. Reduction of valve hysteresis can also be achieved. Fuel delivery and control systems cost can be kept low compared to using multi-point injection where high flow injectors are required for each cylinder.</div> <div class="htmlview paragraph">A gas flow sensor is placed in the CNG stream to monitor mass gas flow rate. The gas flow sensor is based on the hot wire anemometry concept, currently used in mass air flow measurement.</div> <div class="htmlview paragraph">Topics regarding CNG composition effects on sensor output, temperature effects, pressure effects, high pressure noise management and oil contamination test results are important to the operation of the gas flow sensor and will be described in this paper.</div> <div class="htmlview paragraph">A new 10 mm sensor concept is also presented for cost reduction. The manufacturing process is also simplified.</div>

An electronic control unit (ECU) is designed for a compressed natural gas (CNG) engine on the basis of circuit simulation and modelling. The ignition drive circuit and power-off delay circuit are discussed, with emphasis on circuit simulation, and resistance matching for the sensor processing circuit is described. Design of the software of the CNG control system is based on modelling. A TargetLink model of an air—fuel ratio closed-loop control system is presented. The CNG ECU has been applied successfully in bench tests. The results of bench tests have shown that the hardware meets CNG control system requirements; actuators can be controlled precisely, and the performance of the CNG engine can reach design targets. Circuit simulation and modelling are good methods for developing the ECU design for CNG engine systems. Quality of hardware and software design can be ensured, and the development cycle and costs can be reduced.

<div class="htmlview paragraph">A cam actuated injection system timed to inject CNG fuel near the engine intake valve in the intake manifold at the end of suction stroke, but just before the closure of intake valve, has been designed, developed and incorporated in the S.I. engine. Details of the injection system hardware and injector drive mechanism developed are presented. A comparative experimental evaluation of the engine fuel economy and exhaust CO and NO<sub>x</sub> emission levels using premixed CNG-air induction system and Timed Manifold Injection(TMI) system developed is depicted. Engine test results show that with premixed CNG induction system the engine uses a relatively richer gas-air mixture as compared to that with TMI system. Power loss of the engine with premixed charge induction retrofit gets eliminated by using TMI system. Engine exhaust CO and NO<sub>x</sub> emission levels have been, in general, found to be lower with TMI system developed.</div>

The use of compressed natural gas (CNG) as a transportation fuel has been identified as one strategy that can help ameliorate some problems, which include a growing dependence on imported oil (and all its ramifications) and the persistent contributions that mobile sources make to urban air pollution, associated with the use of conventional petroleum fuels. The attributes and limitations of CNG as a fuel for spark-ignition engines have been presented by others. The attributes are associated with its high octane rating, low cost relative to other alternative fuels, its availability, the absence of running and diurnal evaporative emissions, and its demonstrated potential for producing extremely low exhaust emissions-particularly if the volatile organic compounds (VOCs) emitted are expressed in terms of reactivity adjusted non-methane organic gases (RANMOG). The limitations associated with the use of CNG include its limited refueling infrastructure, the cost of refueling facilities, the cost of on-board fuel storage tanks, and its relatively low energy density. Because one impediment to CNG use is the cost associated with producing a CNG-powered vehicle, a study was initiated at the University of Tennessee under sponsorship by the Saturn Corporation to determine how a CNG vehicle (specifically, a 1991 Saturn SL1) could be engineered so it could be produced with a minimal impact on the production of the base vehicle. The present study was undertaken to further investigate the emissions reduction potential of the Saturn CNG vehicle. In the previous study the role of exhaust gas recirculation was not thoroughly investigated. Those involved in the study agreed that the NO{sub x} levels could be brought down well below California ULEV levels without increasing either the non-methane organic gases or the CO levels.

<div>The purpose of the article is to evaluate the cooling performance efficiency of a Compressed Natural Gas (CNG) medium commercial vehicle with a viscous fan, fresh air cleaner, and choked air cleaner in comparison with limits prescribed in the Indian Standard (IS) 14557. Due to the increase in CNG availability, a shift is observed in the market demand for CNG vehicles. The earlier CNG vehicle duty cycle was limited to plain roads and some limited cities, but now vehicles are being used for a short trip to nearby hilly routes thereby shifting the application of the use of a CNG vehicle. CNG vehicles can now be operated in hilly areas where power and torque demand is maximum and operates at lower vehicle speeds and in lower gears. The subjected vehicles are designed for haulage applications to operate with conventional fixed fans, which are permanently engaged, and smaller radiators. The subjected vehicle was previously designed as per the requirements of the existing road application with a fixed fan and small radiator. Vehicle configuration was modified to the viscous fan and bigger radiator available as off-the-shelf components from the component suppliers. Viscous fans operate only when the coolant temperature goes beyond certain limits for better cooling performance of the engine, lower cabin noise, and higher fuel efficiencies.</div> <div>The main objective of this article is to compare the thermal behavior in different vehicle configurations by data acquisition and thereby establish the fact that subjected CNG vehicles can be used in difficult terrains due to broad CNG availability with maximum performance. The results obtained during the experiment with a smaller fixed fan and bigger viscous fan are at an ambient temperature above 35°C and, for a time, more than 5 minutes as specified in IS 14557. Base data is collected with the existing configuration of a vehicle with a small fixed fan and small radiator. Afterward vehicle configuration is changed to the viscous fan and bigger radiator and tested at conditions worse than as specified in the test standard, i.e., ambient temperature more than 35°C and, for a time, more than 5 minutes to ensure driveability in all terrains. Then the experiment is conducted at maximum power condition with fresh air cleaner and choked air cleaner. Another experiment is conducted to check the worst-case running in maximum torque condition with fresh air cleaner and choked air cleaner. After establishing the results in the first and second experiments, another two experiments were conducted to check the actual performance of the vehicle in plains and hilly route simulation as well.</div>

The pursuit of achieving zero carbon emissions by 2050 has led to the implementation of green technologies in the maritime industry. One crucial aspect is the adoption of alternative fuels, with a focus on non-fossil fuels to enhance energy efficiency and minimize emissions during ship operations. This study explores the innovative dual fuel diesel – Compressed Natural Gas (CNG) technology, which offers relatively low emissions with uncomplicated modifications to the diesel engine. CNG is injected into the intake manifold, addressing the need for cleaner fuel options. However, the evolution of this technology has encountered challenges such as methane slip resulting from incomplete combustion. This research proposes an intervention using hydrogen within the combustion chamber to improve combustion quality. Oxy-hydrogen gas (HHO), a carbon-free fuel derived from water through electrolysis, is considered as a potential solution. The utilization of HHO serves as a substitute for pure H2 due to its more feasible production and application, considering the global limitations in hydrogen storage and usage in transportation. The study aims to investigate the impact of HHO on the performance and emissions of dual fuel engines. Experimental tests are conducted under low loads to simulate critical operational points of the engine. Results indicate that the dual fuel system exhibits significant fuel savings, particularly with increasing injection duration. However, the need for additional oxygen to enhance combustion perfection must be balanced. HHO injection demonstrates the potential to improve engine performance, leveraging the oxygen content in HHO and the positive characteristics of hydrogen with its high Lower Heating Value (LHV). Furthermore, the research suggests that HHO injection can mitigate methane slip issues associated with dual fuel engine operations, offering a promising avenue for emission reduction

BASF Catalysts announces opening of new emission control catalyst plant in Russia

Compressed natural gas (CNG) automobile is an emerging new energy car. How to optimally control the ignition advance angle of engine is the key technology of CNG electronic control system. At present, the control based on the MAP graph is used usually, but this control method has some shortages, for example larger data, poor adaptive capacity and difficulties in data updating. BP neural network control has adaptive and self-learning, nonlinear processing ability and high generalization, and faults tolerant ability in processing information. In this paper, BP neural network is used to control natural the ignition advance of engine in order to solve the shortages of the MAP picture control. Simulations experiment shows the feasibility and advantage of this method.

This article, written by Editorial Manager Adam Wilson, contains highlights of paper OTC 23261, ’Development of CO2-Tolerant LNG-Production System,’ by JungHan Lee, Jeheon Jung, and Kyeongmin Kim, SPE, Daewoo Shipbuilding and Marine Engineering, prepared for the 2012 Offshore Technology Conference, Houston, 20 April-3 May. The paper has not been peer reviewed. During natural gas liquefaction, CO2 must be removed to prevent icing and plugging in the system. The CO2-removal system may be the most important part of the gas-treatment system. CO2 removal systems require complicated amine contactor and regeneration systems with substantial heat sources. The CO2-tolerant natural-gas-liquefaction system called cluster liquefaction accepts approximately 1% of CO2 for the liquefaction and related systems. The CO2-tolerant characteristics of this liquefaction process will provide a multifold safety margin against CO2 problems in cryogenic systems and valves. CO2-Tolerant Liquefied-Natural-Gas (LNG) Production System Considerations. Natural gas liquefaction at higher pressures and equivalent higher liquefaction temperatures has the advantages of reducing liquefaction energy and adopting more-efficient refrigerant. Despite the advantages, the higher-pressure storage requirement for the produced LNG has been a cost burden in overall LNG chains. For that reason, natural gas liquefaction at higher pressures has not been adopted by the industry. The specific weight ratio (SWR) of natural gas, defined as the natural gas weight divided by the containment system weight, is an important indication of capital expenditures. The typical SWR of conventional LNG is approximately 10–20 times that of compressed natural gas (CNG). Even for the increased- pressure LNG, the SWR is typically 10 times that for CNG. Hence, storage as a liquid after cooling and insulation is far more efficient than CNG. For increased-pressure LNG, the main cost contributor has been the cryogenic material for the higher pressure. However, if a cost-effective solution for increased-pressure containment is developed, it may become a viable option. Examples. Intermediate-Pressure LNG (20 bara, 1% CO2). Substantial CO2 can be dissolved in LNG produced at increased pressure. CO2 in the LNG should be liquid, not solid or as two phases. During cool down at a predetermined pressure, the feed gas can pass through the solid formation region in the interim stage. Hence, this region should be avoided by liquefying the natural gas at a higher pressure before reducing the pressure. If the CO2 level is sufficiently lowered during the gas treatment, the solid formation can be avoided regard-less of the liquefaction temperatures and processes.

The addition of Compressed natural gas as a complement to diesel in compression ignition engines in dual-fuel 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.

Chandler Evans Engineering conducted a test and evaluation program to uncover problem areas of fuel control systems using emulsified fuel. Basic control components and a complete control system were tested as were fuel characteristics pertaining to a control, exposure effects of typical control system materials to the fuel, and temperature and pressure properties of emulsified fuel. Since the absolute quantity of fuel (1000 gal) made available for the program limited testing, no endurance tests were performed. General variations in control component and system performance when operated with JP-4 and emulsified JP-4 appear to be minor. Exposure of typical fuel-control materials indicates the fuel’s highly corrosive nature, which requires special consideration in material selection. The temperature and pressure properties of this fuel, although evaluated from testing, may be used as order of magnitude indication only, based on the one batch of emulsified JP-4 fuel tested. The results, which could be quite different on other batches of the same fuel — or on any of the many other emulsified-type fuels under development, indicate the general field of emulsified fuels.

Natural gas (NG) liquefaction and compression are energy intensive processes which make up a significant portion of the overall delivered price of liquefied NG (LNG) and compressed NG (CNG). Increases in system efficiency and/or process changes which reduce the required amount of work will improve the overall economics of NG as a vehicle fuel. This paper describes a method of reducing the delivered cost of LNG by liquefying the gas above ambient pressures. Higher pressure LNG is desirable because OEM NG engine manufacturers would like NG delivered to the engine intake manifold at elevated pressures to avoid compromising engine performance. Producing LNG at higher pressures reduces the amount of work required for liquefaction but it is only practical when the LNG is liquefied on-site. Using a thermo-economic approach, it is shown that NG fuel costs can be reduced by as much as 10% when producing LNG at higher pressures. A reduction in the delivered cost is also demonstrated for CNG produced on-site from high pressure LNG.

Petroleum fuels used in motor vehicles are a major source of local air pollutants and greenhouse gas emissions in Dhaka, the capital of Bangladesh, which already has poor air quality. Lack of their own oil resources also presents a major challenge to the policymakers regarding the sustainability of the transportation system. Under this circumstance, conversion of petroleum vehicles to run on compressed natural gas (CNG) offers multiple benefits to the country. This chapter quantifies the social benefits due to a government initiative that led to widespread conversion of petroleum motor vehicles to CNG vehicles. An impact-pathway model has been developed to relate the changes in emissions resulting from the policy to changes in ambient air quality and resulting number of avoided premature deaths. It is estimated that around 11,100 premature deaths can be avoided in Dhaka annually as a result of a complete switch from petroleum to CNG vehicles. This amounts to a saving of USD 1.33 billion a year, which is around 1.3 % of the GDP of the country. For climate benefits, impacts of black carbon (BC), organic carbon (OC), and SO2 have been considered, in addition to the traditional greenhouse gases (GHG), CO2 and methane. Although CNG conversion was detrimental from a climate change perspective using the changes in CO2 and methane only (methane emissions increased), after considering all the global pollutants (especially the reduction in black carbon) the conversion strategy was beneficial. Considering the damage costs of CO2, we find a benefit of around USD 25 million in a year, which is small compared to the health benefits. The strategy also helps the country save around USD 620 million worth of foreign currency a year. This indicates that policies focusing on individual country’s strengths can have large benefits in securing a sustainable energy future in the transportation sector.

Nigeria's transportation sector is heavily reliant on petroleum products, with diesel and petrol accounting for the majority of fuel consumption. However, recent developments such as the removal of petrol subsidies, volatile global oil prices, recurrent fuel scarcity, rising petrol costs, and the increasing need to address environmental concerns, particularly greenhouse gas emissions from fossil fuels, have created significant challenges for public and private transport operators. As a response, alternative fuels such as Compressed Natural Gas (CNG) and Liquefied Natural Gas (LNG) have emerged as viable options. This study evaluates the current state of adoption of gas fuels in Nigeria's transport sector, analyzing their economic, environmental, and safety implications. It further examines the technical properties of CNG, its benefits, risks, emissions profile, and effects on engine performance. Employing mathematical modeling and numerical simulation approach, the research forecasts the transition from conventional fuels to gas fuels and its effects on emissions and fleet composition over time. Drawing insights from recent industry developments, news reports, and global case studies, the paper identifies major barriers to adopting natural gas vehicles and explore the potential for large-scale implementation in Nigeria. The findings reveal that CNG offers several advantages over both diesel and petrol, including notable reductions in emissions, costs, and reliance on imported petroleum products. This paper examines the feasibility of adopting gas fuels as alternative fuels in Nigeria's transport sector, with a particular focus on compressed natural gas (CNG) and the adoption of Natural Gas Vehicles (NGVs).

The present study elucidates on PM2.5 (particle aerodynamic diameter ≤ 2.5 μm) bound trace metals characterization from on-road light-duty vehicles during on-road operation and their health risk assessment for adults and children. The vehicles assessed in present work included 4-wheelers passenger cars with a different age group of Bharat Stage (BS) II, III, and IV and different fuel type [diesel, gasoline and compressed natural gas (CNG)]. To understand the particle losses, particle formation, and homogenous mixing, firstly, a new portable dilution system (PDS) was designed for diluting the exhaust with adequate aerosol formation and growth, and evaluated beforehand under controlled condition in laboratory for diesel vehicles over a wide range of dilution ratio (30:1, 60:1, and 90:1). For on-road experiments, a PDS, a heated duct, a gas analyzer, an exhaust velocity probe, a temperature, and relative humidity probe were mounted on Aerosol Emissions Measurement System (AEMS) and it was towed behind the vehicle. Total 46 experiments were performed on a mixed traffic route in Delhi city, and PM2.5 mass was collected on Teflon and quartz filter using multi-stream PM2.5 sampler. Total 17 trace metals (Al, Ag, As, Ba, Co, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Se, Sr, Ti, V, and Zn) were characterized on Teflon filters using Induced Coupled Plasma-Mass Spectrometry (ICP-MS). Out of these metals, the non-carcinogenic and carcinogenic risks for adults and children were calculated for 5 metals namely Cr, Mn, Ni, Zn, and Pb. Trace metals concentration was highest in exhaust emitted from 4W-diesel followed by 4W-gasoline, 3W-CNG, and 2W-gasoline. Trace metals such as Cr, Mn, Ni, Zn, and Pb were present in high amount (25.2 ± 8.6 μg m−3). The carcinogenic risk from Cr was considerably higher than tolerable risk (10−4), while the risk from other metals such as Ni, As, Cd, and Pb was within the range of safe (10−6) and tolerable (10−4) level. Overall, the human health risks associated with the exposure to PM2.5 emitted from gasoline and CNG vehicles were higher than that from diesel vehicle. This estimated risk in this work can help in refining the burden of disease and crafting policy to help reduce the exposures. This study is limited only for PM2.5 bound trace metals and associated health risk from on-road vehicle emissions. However, poly-aromatic hydrocarbons (PAHs), perfluorinated compounds (PFCs), and semi-volatile compounds in vehicular exhaust can also impose a severe risk to human health which needs to be assessed to evaluate combined risk.