Optimal Mission Analysis Accounting for Engine Aging and Emissions

Author(s):  
M. Kelaidis ◽  
N. Aretakis ◽  
A. Tsalavoutas ◽  
K. Mathioudakis

This paper describes an aircraft mission analysis procedure, comprising a flight simulation module, an engine model and an optimization method. The incorporation of engine deterioration modeling extends this procedure’s ability to estimate the on board performance of a given engine as it ages through time and use. Additionally, in order to investigate the environmental impact, pollutant emissions semi-empirical correlations have been introduced, after being adapted to available emissions data. The proposed procedure allows the optimization of a flight scenario for a variety of aircrafts, missions, and engine condition combinations, using an optimization method. The values of mission profile characteristics (e.g. cruise, altitude, and speed) that provide the optimum overall performance, regarding fuel conservation, time related costs, or pollutants production, are studied.

Author(s):  
M. Kelaidis ◽  
N. Aretakis ◽  
A. Tsalavoutas ◽  
K. Mathioudakis

An aircraft mission analysis procedure, accounting for engine aging deterioration and incorporating emission estimation capability, is presented. It consists of three main modules: a flight simulation module, an engine performance simulation module, and an optimizer. A key feature of the approach is the incorporation of engine deterioration modeling. This extends the procedure’s ability to estimate onboard performance of an engine as it ages through time and usage. Additionally, the possibility to investigate environmental impact is offered through pollutant emission semi-empirical correlations, which are coupled to the engine performance calculations. The adaptive character of the models employed allows for accurate performance and emission estimations once an initial set of data is available for the engine. The proposed procedure allows the optimization of a flight scenario for a variety of aircrafts, missions, and engine condition combinations in order to meet predefined criteria. Mission profile characteristics (e.g., cruise, altitude, and speed) providing optimum overall performance in terms of fuel conservation, time related costs, or pollutant production are studied.


Author(s):  
Michael Benz ◽  
Markus Hehn ◽  
Christopher H. Onder ◽  
Lino Guzzella

This paper proposes a novel optimization method that allows a reduction in the pollutant emission of diesel engines during transient operation. The key idea is to synthesize optimal actuator commands using reliable models of the engine system and powerful numerical optimization methods. The engine model includes a mean-value engine model for the dynamics of the gas paths, including the turbocharger of the fuel injection, and of the torque generation. The pollutant formation is modeled using an extended quasi-static modeling approach. The optimization substantially changes the input signals, such that the engine model is enabled to extrapolate all relevant outputs beyond the regular operating area. A feedforward controller for the injected fuel mass is used to eliminate the nonlinear path constraints during the optimization. The model is validated using experimental data obtained on a transient engine test bench. A direct single shooting method is found to be most effective for the numerical optimization. The results show a significant potential for reducing the pollutant emissions during transient operation of the engine. The optimized input trajectories derived assist the design of sophisticated engine control systems.


Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1036 ◽  
Author(s):  
Xinying Xu ◽  
Qi Chen ◽  
Mifeng Ren ◽  
Lan Cheng ◽  
Jun Xie

Increasing the combustion efficiency of power plant boilers and reducing pollutant emissions are important for energy conservation and environmental protection. The power plant boiler combustion process is a complex multi-input/multi-output system, with a high degree of nonlinearity and strong coupling characteristics. It is necessary to optimize the boiler combustion model by means of artificial intelligence methods. However, the traditional intelligent algorithms cannot deal effectively with the massive and high dimensional power station data. In this paper, a distributed combustion optimization method for boilers is proposed. The MapReduce programming framework is used to parallelize the proposed algorithm model and improve its ability to deal with big data. An improved distributed extreme learning machine is used to establish the combustion system model aiming at boiler combustion efficiency and NOx emission. The distributed particle swarm optimization algorithm based on MapReduce is used to optimize the input parameters of boiler combustion model, and weighted coefficient method is used to solve the multi-objective optimization problem (boiler combustion efficiency and NOx emissions). According to the experimental analysis, the results show that the method can optimize the boiler combustion efficiency and NOx emissions by combining different weight coefficients as needed.


Author(s):  
Alex Oliveira ◽  
Junfeng Yang ◽  
Jose Sodre

Abstract This work evaluated the effect of cooled exhaust gas recirculation (EGR) on fuel consumption and pollutant emissions from a diesel engine fueled with B8 (a blend of biodiesel and Diesel 8:92%% by volume), experimentally and numerically. Experiments were carried out on a Diesel power generator with varying loads from 5 kW to 35 kW and 10% of cold EGR ratio. Exhaust emissions (e.g. THC, NOX, CO etc.) were measured and evaluated. The results showed mild EGR and low biodiesel content have minor impact of engine specific fuel consumption, fuel conversion efficiency and in-cylinder pressure. Meanwhile, the combination of EGR and biodiesel reduced THC and NOX up to 52% and 59%, which shows promising effect on overcoming the PM-NOX trade-off from diesel engine. A 3D CFD engine model incorporated with detailed biodiesel combustion kinetics and NOx formation kinetics was validated against measured in-cylinder pressure, temperature and engine-out NO emission from diesel engine. This valid model was then employed to investigate the in-cylinder temperature and equivalence ratio distribution that predominate NOx formation. The results showed that the reduction of NOx emission by EGR and biodiesel is obtained by a little reduction of the local in-cylinder temperature and, mainly, by creating comparatively rich combusting mixture.


Author(s):  
Donald M. Newburry ◽  
Arthur M. Mellor

Semi–empirical equations model the dominant subprocesses involved in pollutant emissions by assigning specific times to the fuel evaporation, chemistry, and turbulent mixing. They then employ linear ratios of these times with model constants established by correlating data from combustors with different geometries, inlet conditions, fuels, and fuel injectors to make a priori predictions. In this work, thermal NOx emissions from two heavy–duty, dual fuel (natural gas and fuel oil #2) diffusion flame combustors designated A and B operating without inert injection are first predicted, and then correlated using three existing semi–empirical approaches termed the Lefebvre (AHL) model, the Rizk–Mongia (RM) model, and the characteristic time model (CTM). Heterogeneous effects were found to be significant, as fuel droplet evaporation times were required to align the natural gas and fuel oil data. Only the RM model and CTM were employed to study this phenomenon. The CTM achieved the best overall prediction and correlation, as the data from both combustors fell within one standard deviation of the predicted line. The AHL and RM models were not able to account for the geometries of the two combustors. For Combustor A the CTM parameter correlated the data in a highly linear manner, as expected, but for Combustor B there was significant curvature. Using the CTM this was shown to be a residence time effect.


2019 ◽  
Vol 11 (23) ◽  
pp. 6728 ◽  
Author(s):  
Zhang ◽  
Huang ◽  
Liu ◽  
Li

High-efficiency taxiing for safe operations is needed by all types of aircraft in busy airports to reduce congestion and lessen fuel consumption and carbon emissions. This task is a challenge in the operation and control of the airport’s surface. Previous studies on the optimization of aircraft taxiing on airport surfaces have rarely integrated waiting constraints on the taxiway into the multi-objective optimization of taxiing time and fuel emissions. Such studies also rarely combine changes to the airport’s environment (such as airport elevation, field pressure, temperature, etc.) with the multi-objective optimization of aircraft surface taxiing. In this study, a multi-objective optimization method for aircraft taxiing on an airport surface based on the airport’s environment and traffic conflicts is proposed. This study aims to achieve a Pareto optimized taxiing scheme in terms of taxiing time, fuel consumption, and pollutant emissions. This research has the following contents: (1) Previous calculations of aircraft taxiing pathways on the airport’s surface have been based on unimpeded aircraft taxiing. Waiting on the taxiway is excluded from the multi-objective optimization of taxiing time and fuel emissions. In this study, the waiting points were selected, and the speed curve was optimized. A multi-objective optimization scheme under aircraft taxiing obstacles was thus established. (2) On this basis, the fuel flow of different aircraft engines was modified with consideration to the aforementioned environmental airport differences, and a multi-objective optimization scheme for aircraft taxiing under different operating environments was also established. (3) A multi-objective optimization of the taxiing time and fuel consumption of different aircraft types was realized by acquiring their parameters and fuel consumption indexes. A case study based on the Shanghai Pudong International Airport was also performed in the present study. The taxiway from the 35R runway to the 551# stand in the Shanghai Pudong International Airport was optimized by the non-dominant sorting genetic algorithm II (NSGA-II). The taxiing time, fuel consumption, and pollutant emissions at this airport were compared with those of the Kunming Changshui International Airport and Lhasa Gonggar International Airport, which have different airport environments. Our research conclusions will provide the operations and control departments of airports a reference to determine optimal taxiing schemes.


Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4561 ◽  
Author(s):  
José R. Serrano ◽  
Francisco J. Arnau ◽  
Jaime Martín ◽  
Ángel Auñón

Growing interest has arisen to adopt Variable Valve Timing (VVT) technology for automotive engines due to the need to fulfill the pollutant emission regulations. Several VVT strategies, such as the exhaust re-opening and the late exhaust closing, can be used to achieve an increment in the after-treatment upstream temperature by increasing the residual gas amount. In this study, a one-dimensional gas dynamics engine model has been used to simulate several VVT strategies and develop a control system to actuate over the valves timing in order to increase diesel oxidation catalyst efficiency and reduce the exhaust pollutant emissions. A transient operating conditions comparison, taking the Worldwide Harmonized Light-Duty Vehicles Test Cycle (WLTC) as a reference, has been done by analyzing fuel economy, HC and CO pollutant emissions levels. The results conclude that the combination of an early exhaust and a late intake valve events leads to a 20% reduction in CO emissions with a fuel penalty of 6% over the low speed stage of the WLTC, during the warm-up of the oxidation catalyst. The same set-up is able to reduce HC emissions down to 16% and NOx emission by 13%.


Author(s):  
Hanna Sara ◽  
David Chalet ◽  
Mickaël Cormerais ◽  
Jean-François Hetet

Since the main interest worldwide of green environment companies is to reduce pollutant emissions, the automotive industry is aiming to improve engine efficiency in order to reduce fuel consumption. Recently, studies have been shifted from upgrading the engine to the auxiliary systems attached to it. Thermal management is one of the successful fields that has shown promise in minimizing fuel consumption and reducing pollutant emissions. Throughout this work, a four-cylinder turbocharged diesel engine model was developed on GT-Power. Also, a thermal code has been developed in parallel on GT-Suite, in which the different parts of the coolant and lubricant circuits were modeled and calibrated to have the best agreement with the temperature profile of the two fluids in the system. Once the model was verified, hot coolant storage, a thermal management strategy, was applied to the system to assess the fuel consumption gain. The storage tank was located downstream the thermostat and upstream the radiator with three valves to control the coolant flow. The place was chosen to avoid negative impact on the cold start-up of the engine when the tank is at the ambient temperature. This strategy was applied on different driving cycles such as the NEDC, WLTC, CADC (urban and highway), and an in-house developed driving cycle. The ambient temperature was varied between −7°C to represent the coldest winter and 20°C. The results of this study summarize the ability of the hot coolant storage strategy in reducing the fuel consumption, and show the best driving cycle that needs to be applied on along with the influence of the different ambient temperatures.


Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 261
Author(s):  
Mario Picerno ◽  
Sung-Yong Lee ◽  
Michal Pasternak ◽  
Reddy Siddareddy ◽  
Tim Franken ◽  
...  

The increasing requirements to further reduce pollutant emissions, particularly with regard to the upcoming Euro 7 (EU7) legislation, cause further technical and economic challenges for the development of internal combustion engines. All the emission reduction technologies lead to an increasing complexity not only of the hardware, but also of the control functions to be deployed in engine control units (ECUs). Virtualization has become a necessity in the development process in order to be able to handle the increasing complexity. The virtual development and calibration of ECUs using hardware-in-the-loop (HiL) systems with accurate engine models is an effective method to achieve cost and quality targets. In particular, the selection of the best-practice engine model to fulfil accuracy and time targets is essential to success. In this context, this paper presents a physically- and chemically-based stochastic reactor model (SRM) with tabulated chemistry for the prediction of engine raw emissions for real-time (RT) applications. First, an efficient approach for a time-optimal parametrization of the models in steady-state conditions is developed. The co-simulation of both engine model domains is then established via a functional mock-up interface (FMI) and deployed to a simulation platform. Finally, the proposed RT platform demonstrates its prediction and extrapolation capabilities in transient driving scenarios. A comparative evaluation with engine test dynamometer and vehicle measurement data from worldwide harmonized light vehicles test cycle (WLTC) and real driving emissions (RDE) tests depicts the accuracy of the platform in terms of fuel consumption (within 4% deviation in the WLTC cycle) as well as NOx and soot emissions (both within 20%).


2020 ◽  
Vol 17 (5) ◽  
pp. 172988142095404
Author(s):  
Wei Wei ◽  
Ganwei Cai ◽  
Junjie Gong ◽  
Caixia Ban

Most driving torques in serial industrial robots are used to overcome the weight of the robot. Although actuators account for a large proportion of the total mass of a robot, they have yet to become a positive factor that enables the robot to achieve gravity balance. This study presents a host–parasite structure to reconstruct the distribution of actuators and achieve gravity balance in robots. First, based on the characteristics of tree–rattan mechanisms, a method for calculating the degrees of freedom and a symbolic representation method for the distribution of branched chains are formulated for host–parasite mechanisms. Second, a configuration analysis and optimization method for host–parasite structure-based robots and a robot prototype are presented. Finally, four host–parasite mechanisms/robots (A, B, C, and D) are compared. The results are as follows. If more parasitic branched chains are added to the yz plane, the loads along axes 2 and 3 become more balanced, which significantly increases the stiffnesses of the mechanism in the y- and z-directions ( Ky and Kz, respectively). If the additional branched chains are closer to the site of maximum deformation, the stiffness of the mechanism in the z-direction ( Kz) increases more significantly. Of the four mechanisms, mechanism D has the best overall performance. The joint torques of mechanism D along axes 2 and 3 are lower than those of mechanism A by 99.78% and 99.18%, respectively. In addition, Kx, Ky, and Kz of mechanism D are 100.56%, 336.19%, and 385.02% of those of mechanism A, respectively. Moreover, the first-order natural frequency of mechanism D is 135.94% of that of mechanism A. Host–parasitic structure is conducive to improving the performance of industrial robots.


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