NOx Emissions From Oceangoing Ships: Calculation and Evaluation

2003 ◽  
Author(s):  
Horst W. Koehler
Keyword(s):  
Fuel Consumption ◽  
Diesel Engines ◽  
Atmospheric Chemistry ◽  
Pollutant Emissions ◽  
Nox Emissions ◽  
Consumption Rates ◽  
Type Size ◽  
Mode Of Transportation ◽  
Engine Type ◽  
Bunker Fuel

Currently available global inventories of nitrogen oxides (NOx) and other pollutant emissions from merchant ships are based, at least partly, on data published by international marine bunker fuel suppliers. However, the uncertainty of such data seems to be quite high, because the figures released by bunker fuel companies might be incomplete or based, for example, on data collected from only the largest ports. Besides, all similar other studies conducted so far were based on simplified average emission and fuel consumption characteristics of diesel engines and did not take into account variations with engine type, size, engine load and engine speed, as well as only being valid for new state-of-the-art diesel engines as supplied by the industry today. Furthermore, fuel consumption rates of the auxiliary engine equipment onboard vessels were neglected. The author therefore adopted a different approach by calculating the actual bunker amount and the fleet’s 2001 NOx emissions in order to reduce uncertainty in existing inventories and to assist in achieving a better modeling of the effects of ships’ pollutants on atmospheric chemistry. For this study, all ships of 100 gross tonnage (gt) and above were taken into account. This methodology resulted in a significantly higher world fleet fuel consumption, and, consequently, much higher oceangoing ships’ NOx emissions than known or anticipated so far. In spite of the fleet’s high NOx emission rate in absolute figures this paper shows, that when emissions are based on the annual seaborne trade, merchant shipping is an environmentally efficient mode of transportation of freight.

A Multidisciplinary Approach for the Comprehensive Assessment of Integrated Rotorcraft–Powerplant Systems at Mission Level

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
Ioannis Goulos ◽  
Fakhre Ali ◽  
Konstantinos Tzanidakis ◽  
Vassilios Pachidis ◽  
Roberto d'Ippolito
Keyword(s):  
Environmental Impact ◽  
Fuel Consumption ◽  
Comprehensive Assessment ◽  
Pollutant Emissions ◽  
Operational Performance ◽  
Civil Aviation ◽  
Accurate Estimation ◽  
Nox Emissions ◽  
Reactor Model ◽  
Stirred Reactor

This paper presents an integrated methodology for the comprehensive assessment of combined rotorcraft–powerplant systems at mission level. Analytical evaluation of existing and conceptual designs is carried out in terms of operational performance and environmental impact. The proposed approach comprises a wide-range of individual modeling theories applicable to rotorcraft flight dynamics and gas turbine engine performance. A novel, physics-based, stirred reactor model is employed for the rapid estimation of nitrogen oxides (NOx) emissions. The individual mathematical models are implemented within an elaborate numerical procedure, solving for total mission fuel consumption and associated pollutant emissions. The combined approach is applied to the comprehensive analysis of a reference twin-engine light (TEL) aircraft modeled after the Eurocopter Bo 105 helicopter, operating on representative mission scenarios. Extensive comparisons with flight test data are carried out and presented in terms of main rotor trim control angles and power requirements, along with general flight performance charts including payload-range diagrams. Predictions of total mission fuel consumption and NOx emissions are compared with estimated values provided by the Swiss Federal Office of Civil Aviation (FOCA). Good agreement is exhibited between predictions made with the physics-based stirred reactor model and experimentally measured values of NOx emission indices. The obtained results suggest that the production rates of NOx pollutant emissions are predominantly influenced by the behavior of total air inlet pressure upstream of the combustion chamber, which is affected by the employed operational procedures and the time-dependent all-up mass (AUM) of the aircraft. It is demonstrated that accurate estimation of on-board fuel supplies ahead of flight is key to improving fuel economy as well as reducing environmental impact. The proposed methodology essentially constitutes an enabling technology for the comprehensive assessment of existing and conceptual rotorcraft–powerplant systems, in terms of operational performance and environmental impact.

Optimization of Engine Efficiency for Diesel Engine Equipped With EGR-VGT and Aftertreatment Systems

2019 ◽  
Author(s):  
Kuo Yang ◽  
Pingen Chen
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Diesel Engines ◽  
Intrinsic Property ◽  
Nox Emission ◽  
Nox Emissions ◽  
Minimum Phase ◽  
Engine Efficiency ◽  
Simulation Results ◽  
Aftertreatment Systems

Abstract Engine efficiency improvement is very critical for medium to heavy-duty vehicles to reduce Diesel fuel consumption and enhance U.S. energy security. The tradeoff between engine efficiency and NOx emissions is an intrinsic property that prevents modern Diesel engines, which are generally equipped with exhaust gas recirculation (EGR) and variable geometry turbocharger (VGT), from achieving the optimal engine efficiency while meeting the stringent NOx emission standards. The addition of urea-based selective catalytic reduction (SCR) systems to modern Diesel engine aftertreatment systems alleviate the burden of NOx emission control on Diesel engines, which in return creates extra freedom for optimizing Diesel engine efficiency. This paper proposes two model-based approaches to locate the optimal operating point of EGR and VGT in the air-path loop to maximize the indicated efficiency of turbocharged diesel engine. Simulation results demonstrated that the engine brake specific fuel consumption (BSFC) can be reduced by up to 1.6% through optimization of EGR and VGT, compared to a baseline EGR-VGT control which considers both NOx emissions and engine efficiency on engine side. The overall equivalent BSFCs are 1.8% higher with optimized EGR and VGT control than with the baseline control. In addition, the influence of reducing EGR valve opening on the non-minimum phase behavior of the air path loop is also analyzed. Simulation results showed slightly stronger non-minimum phase behaviors when EGR is fully closed.

scholarly journals Optimal Control of Diesel Engines: Numerical Methods, Applications, and Experimental Validation

2014 ◽  
Vol 2014 ◽  
pp. 1-21 ◽  
Author(s):  
Jonas Asprion ◽  
Oscar Chinellato ◽  
Lino Guzzella
Keyword(s):  
Optimal Control ◽  
Numerical Methods ◽  
Fuel Consumption ◽  
Diesel Engines ◽  
Large Scale ◽  
Experimental Validation ◽  
Control Unit ◽  
Pollutant Emissions ◽  
Control Input ◽  
Dynamic Optimisation

In response to the increasingly stringent emission regulations and a demand for ever lower fuel consumption, diesel engines have become complex systems. The exploitation of any leftover potential during transient operation is crucial. However, even an experienced calibration engineer cannot conceive all the dynamic cross couplings between the many actuators. Therefore, a highly iterative procedure is required to obtain a single engine calibration, which in turn causes a high demand for test-bench time. Physics-based mathematical models and a dynamic optimisation are the tools to alleviate this dilemma. This paper presents the methods required to implement such an approach. The optimisation-oriented modelling of diesel engines is summarised, and the numerical methods required to solve the corresponding large-scale optimal control problems are presented. The resulting optimal control input trajectories over long driving profiles are shown to provide enough information to allow conclusions to be drawn for causal control strategies. Ways of utilising this data are illustrated, which indicate that a fully automated dynamic calibration of the engine control unit is conceivable. An experimental validation demonstrates the meaningfulness of these results. The measurement results show that the optimisation predicts the reduction of the fuel consumption and the cumulative pollutant emissions with a relative error of around 10% on highly transient driving cycles.

Emissions From Various Biodiesel Sources Compared to a Range of Diesel Fuels in DPF Equipped Diesel Engines

2011 ◽  
Author(s):  
Aaron Williams ◽  
Jonathan Burton ◽  
Earl Christensen ◽  
Robert L. McCormick ◽  
John Tester
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Fuel Consumption ◽  
Diesel Engines ◽  
Nox Emissions ◽  
Test Cycle ◽  
Particle Count ◽  
Diesel Fuels ◽  
Total Particle

The purpose of this study was to measure the impact of various sources of petroleum-based and bio-based diesel fuels on regulated emissions and fuel economy in diesel particulate filter (DPF) equipped diesel engines. Two model year 2008 diesel engines were tested with nine fuels including a certification ultra-low sulfur diesel (ULSD), local ULSD, high aromatic ULSD, low aromatic ULSD, and twenty percent blends of biodiesel derived from algae, camelina, soy, tallow, and yellow grease. Regulated emissions were measured over the heavy duty diesel transient test cycle. Measurements were also made of DPF-out particle size distribution and total particle count from a 13-mode steady state test using a fast mobility particle sizer. Test engines were a 2008 Cummins ISB and a 2008 International Maxx Force 10, both equipped with actively regenerated DPFs. Fuel consumption was roughly 2% greater over the transient test cycle for the B20 blends versus certification ULSD in both engines, consistent with the slightly lower energy content of biodiesel. Unlike studies conducted on older model engines, these engines equipped with diesel oxidation catalysts and DPFs showed small or no measurable fuel effect on the tailpipe emissions of total hydrocarbons (THC), carbon monoxide (CO) and particulate matter (PM). No differences in particle size distribution or total particle count were seen in a comparison of certification ULSD and B20 soy, with the exception of engine idling conditions where B20 produced a small reduction in the number of nucleation mode particles. In the Cummins engine, B20 prepared from algae, camelina, soy, and tallow resulted in an approximately 2.5% increase in nitrogen oxides (NOx) compared to the base fuel. The International engine demonstrated a higher degree of variability for NOx emissions, and fuel effects could not be resolved (p > 0.05). The group of petroleum diesel test fuels produced a range of NOx emissions very similar to that caused by blending of biodiesel. Test cycles where an active regeneration of the DPF occurred resulted in a nearly threefold increase in NOx emissions and a 15% increase in fuel consumption. The full quantification of DPF regeneration events further complicates the accurate calculation of fuel impacts on emissions and fuel consumption.

scholarly journals Research on the effects of idling start-stop function on light vehicles fuel consumption and emission under different cycle conditions

2021 ◽  
Vol 268 ◽  
pp. 01030
Author(s):  
Zhicheng Ma ◽  
Tieqiang Fu ◽  
Yuwei Wang ◽  
Wei Zhao ◽  
Luowei Zhang
Keyword(s):  
Fuel Consumption ◽  
Pollutant Emissions ◽  
Nox Emissions ◽  
Saving Rate ◽  
Distribution Characteristics ◽  
Fuel Saving ◽  
Gasoline Vehicles ◽  
Light Vehicle ◽  
Light Gasoline ◽  
Fuel Consumption And Emissions

The idling distribution characteristics of NEDC, WLTC and CLTC conditions were analyzed, and the exhaust emissions and fuel consumption of three light gasoline vehicles when the idling start-stop function was turned on and off under different cycle conditions were measured. The effects of idling start-stop function on light vehicle fuel consumption and emissions under different cycle conditions were analyzed. The results show that the vehicle fuel saving rate of the idling start-stop function in three cycle conditions is WLTC, NEDC and CLTC conditions from low to high. The idling start-stop function has little effect on vehicle gaseous pollutant emissions. On the whole, the the activation of idling start-stop function increases the THC and CO emissions and reduces NOx emissions.

Refinement of working processes of diesel engines converted to gas fuel based on numerical modeling

2020 ◽  
pp. 36-42
Author(s):  
Leonid Valeryevich Plotnikov ◽  
◽  
Andrey Mikhaylovich Kozubskiy ◽  
Alexander Grigoryevich Maximenko ◽  
Leonid Evgenyevich Osipov ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Fuel Consumption ◽  
Diesel Engines ◽  
Significant Part ◽  
Nox Emissions ◽  
Railway Transport ◽  
Working Process ◽  
Reciprocating Engines ◽  
Gas Fuel ◽  
Working Processes

Shunting is an important component of railway transport, a significant part of which is performed by diesel locomotives. Piston engines are the most common locomotive power machines. The paper provides brief information on the trends in modernization of energy machines for diesel locomotives. It also considers the issues of improving the working processes of engines converted to gas fuel on the basis of numerical modeling. The main goal of the simulation is to improve the performance of gas reciprocating engines. The authors propose the option for refinement of the working process for three gas reciprocating engines that decreased the specific fuel consumption to 11.5 % and NOx emissions by 2-10 times while maintaining power within ±10 % compared to basic diesel engines.

Effects of triglyceride gasoline blends on combustion and emissions in a common rail direct injection diesel engine

2017 ◽  
Vol 19 (10) ◽  
pp. 1068-1078 ◽  
Author(s):  
Arunachalam Lakshminarayanan ◽  
Daniel B Olsen ◽  
Perry E Cabot
Keyword(s):  
Fuel Consumption ◽  
Vegetable Oils ◽  
Diesel Engines ◽  
Alternative Fuels ◽  
Direct Injection ◽  
Pollutant Emissions ◽  
Compression Ignition Engine ◽  
Unleaded Gasoline ◽  
Particulate Matter Emissions ◽  
Volume Measurements

This study presents the combustion and emission results using a blend of unrefined triglycerides (straight vegetable oils) and regular unleaded gasoline in a compression ignition engine typically used in farming machinery. Most farm equipment is powered by diesel engines. A sizable cost of producing a crop on a farm can be attributed to fuel—diesel in such cases. Farmers and researchers have been interested in the use of alternative fuels, especially triglycerides, which could potentially bring down the fuel cost portion of the farm input costs. One of the major drawbacks of using unrefined triglycerides is poor cold flow properties due to high density and viscosity. To overcome this, the triglycerides can be blended with gasoline to lower the density and viscosity. This blend has been used in existing diesel engines without the need for any modification to the engine or its control system. The experiments were conducted on a 4.5-L Tier 3 engine. The fuel used was a blend of unrefined canola triglyceride and regular unleaded gasoline (10% by volume). Measurements include mass fraction burned combustion pressure, fuel consumption and pollutant emissions. The fuel consumption of TGB10 was lower than most straight vegetable oils found in the literature, but higher than diesel. The peak pressure of TGB10 was slightly higher than diesel and occurred earlier than diesel. The brake-specific NOx was lower than diesel at lower and no load points. Particulate matter emissions of TGB10 were higher than diesel at rated speed. Total hydrocarbon emissions were generally higher than diesel. CO emissions were lower than diesel except at low or no load points where they were significantly higher.

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