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Viewing 151 to 180 of 16427
2017-03-28
Journal Article
2017-01-0605
Anthony D'Amato, Yan Wang, Dimitar Filev, Enrique Remes
Abstract Government regulations for fuel economy and emission standards have driven the development of technologies that improve engine performance and efficiency. These technologies are enabled by an increased number of actuators and increasingly sophisticated control algorithms. As a consequence, engine control calibration time, which entails sweeping all actuators at each speed-load point to determine the actuator combination that meets constraints and delivers ideal performance, has increased significantly. In this work we present two adaptive optimization methods, both based on an indirect adaptive control framework, which improve calibration efficiency by searching for the optimal process inputs without visiting all input combinations explicitly. The difference between the methods is implementation of the algorithm in steady-state vs dynamic operating conditions.
2017-03-28
Journal Article
2017-01-0603
Vicente Cuapio Espino, Akshay Bichkar, Joycer D. Osorio
Abstract Software development for automotive application requires several iterations in order to tune parameters and strategy logic to operate accordantly with optimal performance. Thus, in this paper we present an optimizer method and tool used to tune calibration parameters related to torque estimation for a hybrid automatic transmission application. This optimizer aims to minimize the time invested during the software calibration and software development phases that could take significant time in order to cover the different driving conditions under which a hybrid automatic transmission can operate. For this reason, an optimization function based on the Nelder-Mead simplex algorithm using Matlab software helps to find optimized calibration values based on a cost function (square sum error minimization).
2017-03-28
Journal Article
2017-01-0602
Vladimir Vasilije Kokotovic, Colby Buckman
Abstract With the trending electrification of vehicle accessory drives brings new control concepts useful in many cases to optimize energy management within the powertrain system. Considering that direct engine drives do not have as much flexibility as independent electric drives, it is apparent that several advantages are to be expected from electric drives. New developed high efficient electric drives can be implemented when considering many vehicle sub-systems. Combinations of continuous varying and discrete flow control devices offer thermal management opportunities across several vehicle attributes including fuel economy, drivability, performance, and cabin comfort. Often new technologies are integrated with legacy systems to deliver maximum value. Leveraging both electrical and mechanical actuators in some cases presents control challenges in optimizing energy management while delivering robust system operation.
2017-03-28
Journal Article
2017-01-0598
Mohammad Reza Amini, Meysam Razmara, Mahdi Shahbakhti
Electronic throttle control is an integral part of an engine electronic control unit (ECU) that directly affects vehicle fuel economy, drivability, and engine-out emissions by managing engine torque and air-fuel ratio through adjusting intake charge flow to the engine. The highly nonlinear dynamics of the throttle body call for nonlinear control techniques that can be implemented in real-time and are also robust to controller implementation imprecision. Discrete sliding mode control (DSMC) is a computationally efficient controller design technique which can handle systems with high degree of nonlinearity. In this paper, a generic robust discrete sliding mode controller design is proposed and experimentally verified for the throttle position tracking problem. In addition, a novel method is used to predict and incorporate the sampling and quantization imprecisions into the DSMC structure. First, a nonlinear physical model for an electromechanical throttle body is derived.
2017-03-28
Journal Article
2017-01-0596
Vittorio Ravaglioli, Federico Stola, Matteo De Cesare, Fabrizio Ponti, Stefano Sgatti
Abstract Upcoming more stringent emission regulations throughout the world pose a real challenge, especially in regard to Diesel systems for passenger cars, where the need of additional after-treatment has a big impact in terms of additional system costs and available packaging space. Therefore, the need for strategies that allow managing combustion towards lower emissions, that require a precise control of the combustion outputs, is definitely increasing. Acoustic emission of internal combustion engines contains a large amount of information related to engine behavior and working conditions. Mechanical noise and combustion noise are usually the main contributions to the noise produced by an engine. In particular, recent research from the same authors of this paper demonstrated that combustion noise can be used as an indicator of the combustion that is taking place inside the combustion chamber and therefore as a reference for the control strategy.
2017-03-28
Journal Article
2017-01-0587
Cetin Gurel, Elif Ozmen, Metin Yilmaz, Didem Aydin, Kerem Koprubasi
Abstract Emissions and fuel economy optimization of internal combustion engines is becoming more challenging as the stringency of worldwide emission regulations are constantly increasing. Aggressive transient characteristics of new emission test cycles result in transient operation where the majority of soot is produced for turbocharged diesel engines. Therefore soot optimization has become a central component of the engine calibration development process. Steady state approach for air-fuel ratio limitation calibration development is insufficient to capture the dynamic behavior of soot formation and torque build-up during transient engine operation. This paper presents a novel methodology which uses transient maneuvers to optimize the air-fuel ratio limitation calibration, focusing on the trade-off between vehicle performance and engine-out soot emissions. The proposed methodology features a procedure for determining candidate limitation curves with smoothness criteria considerations.
2017-03-28
Technical Paper
2017-01-0592
Robin Holmbom, Bohan Liang, Lars Eriksson
1 Turbocharging plays an important role in the downsizing of engines. Model-based approaches for boost control are going to increasing the necessity for controlling the wastegate flow more accurately. In today’s cars, the wastegate is usually only controlled with a duty cycle and without position feedback. Due to nonlinearities and varying disturbances a duty cycle does not correspond to a certain position. Currently the most frequently used feedback controller strategy is to use the boost pressure as the controller reference. This means that there is a large time constant from actuation command to effect in boost pressure, which can impair dynamic performance. In this paper, the performance of an electrically controlled vacuum-actuated waste-gate, subsequently referred to as vacuum wastegate, is compared to an electrical servo-controlled wastegate, also referred to as electric wastegate.
2017-03-28
Journal Article
2017-01-0747
John Storey, Samuel Lewis, Melanie Moses-DeBusk, Raynella Connatser, Jong Lee, Tom Tzanetakis, Kukwon Cho, Matthew Lorey, Mark Sellnau
Abstract Low temperature combustion engine technologies are being investigated for high efficiency and low emissions. However, such engine technologies often produce higher engine-out hydrocarbon (HC) and carbon monoxide (CO) emissions, and their operating range is limited by the fuel properties. In this study, two different fuels, a US market gasoline containing 10% ethanol (RON 92 E10) and a higher reactivity gasoline (RON 80 E0), were compared on Delphi’s second generation Gasoline Direct-Injection Compression Ignition (Gen 2.0 GDCI) multi-cylinder engine. The engine was evaluated at three operating points ranging from a light load condition (800 rpm/2 bar IMEPg) to medium load conditions (1500 rpm/6 bar and 2000 rpm/10 bar IMEPg). The engine was equipped with two oxidation catalysts, between which was located the exhaust gas recirculation (EGR) inlet. Samples were taken at engine-out, between the catalysts, and at tailpipe locations.
2017-03-28
Journal Article
2017-01-0610
Nicolo Cavina, Francesco Ranuzzi, Matteo De Cesare, Enrico Brugnoni
Abstract The most recent European regulations for two- and three-wheelers (Euro 5) are imposing an enhanced combustion control in motorcycle engines to respect tighter emission limits, and Air-Fuel Ratio (AFR) closed-loop control has become a key function of the engine management system also for this type of applications. In a multi-cylinder engine, typically only one oxygen sensor is installed on each bank, so that the mean AFR of two or more cylinders rather than the single cylinder one is actually controlled. The installation of one sensor per cylinder is normally avoided due to cost, layout and reliability issues. In the last years, several studies were presented to demonstrate the feasibility of an individual AFR controller based on a single sensor. These solutions are based on the mathematical modelling of the engine air path dynamics, or on the frequency analysis of the lambda probe signal.
2017-03-28
Journal Article
2017-01-0607
Nahid Pervez, Ace Koua Kue, Adarsh Appukuttan, John Bogema, Michael Van Nieuwstadt
Abstract Designing a control system that can robustly detect faulted emission control devices under all environmental and driving conditions is a challenging task for OEMs. In order to gain confidence in the control strategy and the values of tunable parameters, the test vehicles need to be subjected to their limits during the development process. Complexity of modern powertrain systems along with the On-Board Diagnostic (OBD) monitors with multidimensional thresholds make it difficult to anticipate all the possible scenarios. Finding optimal solutions to these problems using traditional calibration processes can be time and resource intensive. A possible solution is to take a data driven calibration approach. In this method, a large amount of data is collected by collaboration of different groups working on the same powertrain. Later, the data is mined to find the optimum values of tunable parameters for the respective vehicle functions.
2017-03-28
Technical Paper
2017-01-0611
Viktor Leek, Kristoffer Ekberg, Lars Eriksson
1 ABSTRACT Today’s need for fuel efficient vehicles, together with increasing engine component complexity, makes optimal control a valuable tool in the process of finding the most fuel efficient control strategies. To efficiently calculate the solution to optimal control problems a gradient based optimization technique is desirable, making continuously differentiable models preferable. Many existing control-oriented Diesel engine models do not fully posses this property, often due to signal saturations or discrete conditions. This paper offers a continuously differentiable, mean value engine model, of a heavy-duty diesel engine equipped with VGT and EGR, suitable for optimal control purposes. The model is developed from an existing, validated, engine model, but adapted to be continuously differentiable and therefore tailored for usage in an optimal control environment. The changes due to the conversion are quantified and presented.
2017-03-28
Journal Article
2017-01-1092
Jianbo Lu, Sanghyun Hong, Jonathan Sullivan, Guopeng Hu, Edward Dai, Dennis Reed, Ryan Baker
Abstract This paper proposes an approach that uses the road preview data to optimize a shift schedule for a vehicle equipped with an automatic transmission. The road preview is inferred here from the so-called electronic horizon of a digital map that includes road attributes such as road grade, curvature, segment speed limit, functional class, etc. The optimized shift schedule selects the gear ratio whose optimization is conducted through applying a hybrid model predictive control method to the powertrain system, which is modelled as the multiple plants associated with multiple gears together with engine models. The goal of this optimization of shift schedule includes improving real world fuel economy and drivability. The real-world fuel economy gains using the proposed approach are achieved through optimizing gear ratio w.r.t. the road grade variations of the road ahead.
2017-03-28
Journal Article
2017-01-1082
Mohammed Yusuf Ali, Thomas Sanders, Mikhail A. Ejakov, Reda Adimi, Alexander Boucke, Jochen Lang, Gunter Knoll
Abstract Strict requirements for fuel economy and emissions are the main drivers for recent automotive engine downsizing and an increase of boosting technologies. For high power density engines, among other design challenges, valve and guide interactions are very important. Undesirable contact interactions may lead to poor fuel economy, engine noise, valve stem to valve guide seizure, and in a severe case, engine failure. In this paper, the valve stem and valve guide contact behavior is investigated using computational models for the camshaft drive in push and pull directions under several misalignment conditions for an engine with roller finger follower (RFF) valvetrain and overhead cam configuration. An engine assembly analysis with the appropriate assembly and thermal boundary conditions are first carried out using the finite element solver ABAQUS.
2017-03-28
Journal Article
2017-01-1563
Abhijeet Behera, Murugan Sivalingam
Abstract Two and three wheeler vehicles are largely used in many developing and under developing countries because of their lower cost, better fuel economy and easy handling. Although, the construction of them is simpler than the four wheeler vehicle, they pose some problems related to instability. Wobbling is the main cause of instabilities in two wheeler and three wheeler vehicles. In this study, a mathematical model was proposed and developed to determine wobble instability of a two wheeler. Nonlinear equations were formulated by using kinematics and the D’Alembert’s principle with the help of multi body formalism. The non-linear equations found in the study were linearized with respect to rectilinear and upright motion, considering no rolling. It led to formation of matrix. The real part of the Eigen value of the matrix was found to be negative, implication of whose was an asymptotic stable motion.
2017-03-28
Journal Article
2017-01-1297
Robert Peckham, Sumit Basu, Marcelo Ribeiro, Sandra Walker
Abstract This study emphasizes the fact that there lies value and potential savings in harmonizing some of the inherent differences between the USA, EU, and China regulations with respect to the role of vehicle mass and lightweighting within Fuel Economy (FE) and Green House Gas (GHG) regulations. The definition and intricacies of FE and mass regulations for the three regions (USA, EU, and China) have been discussed and compared. In particular, the nuances of footprint-based, curb-mass-based, and stepped-mass-based regulations that lead to the differences have been discussed. Lightweighting is a customer benefit for fuel consumption, but in this work, we highlight cases where lightweighting, as a CO2 enabler, has incentives that do not align with rational customer values. A typical vehicle’s FE performance sensitivity to a change in mass on the standard regional certification drive cycles is simulated and compared across the three regions.
2017-03-28
Journal Article
2017-01-0599
Yichao Guo
Abstract Misfire is generally defined as be no or partial combustion during the power stroke of internal combustion engine. Because a misfired engine will dramatically increase the exhaust emission and potentially cause permanent damage to the catalytic converters, California Air Resources Board (CARB), as well as most of other countries’ on-board diagnostic regulations mandates the detection of misfire. Currently almost all the OEMs utilize crankshaft position sensors as the main input to their misfire detection algorithm. The detailed detection approaches vary among different manufacturers. For example, some chooses the crankshaft angular velocity calculated from the raw output of the crankshaft positon sensor as the measurement to distinguish misfires from normal firing events, while others use crankshaft angular acceleration or the associated torque index derived from the crankshaft position sensor readings as the measurement of misfire detection.
2017-03-28
Journal Article
2017-01-1313
Bao Wang, Jianhua Zhou, Min Xu
Abstract Manufacturing tolerances are inevitable in nature. For the bearings used in internal combustion engines, the manufacturing tolerances of roundness, which is of the micron scale, can be very close to the bearing radial clearance, and as a result the roundness could affect the lubrication of the bearings and thus affecting the friction loss of the engine. However, there is insufficient understanding of this mechanism. This study aims to find out the effects of the amplitude and the phase of journal roundness in the shape of ellipse on the lubrication of engine bearings. The elastohydrodynamic (EHD) theory is applied to model the bearing since the EHD model takes account of the elastic deformation of the journal and the bearing shell. The analysis of the DOE results shows the existence of roundness can be beneficial to the lubrication in some cases.
2017-03-28
Journal Article
2017-01-1513
Young-Chang Cho, Chin-Wei Chang, Andrea Shestopalov, Edward Tate
Abstract The airflow into the engine bay of a passenger car is used for cooling down essential components of the vehicle, such as powertrain, air-conditioning compressor, intake charge air, batteries, and brake systems, before it returns back to the external flow. When the intake ram pressure becomes high enough to supply surplus cooling air flow, this flow can be actively regulated by using arrays of grille shutters, namely active grille shutters (AGS), in order to reduce the drag penalty due to excessive cooling. In this study, the operation of AGS for a generic SUV-type model vehicle is optimized for improved fuel economy on a highway drive cycle (part of SFTP-US06) by using surrogate models. Both vehicle aerodynamic power consumption and under-hood cooling performance are assessed by using PowerFLOW, a high-fidelity flow solver that is fully coupled with powertrain heat exchanger models.
2017-03-28
Journal Article
2017-01-1535
Luca Dalessio, Bradley Duncan, Chinwei Chang, Joaquin Ivan Gargoloff, Ed Tate
Abstract The ultimate goal for vehicle aerodynamicists is to develop vehicles that perform well on the road under real-world conditions. One of the most important metrics to evaluate vehicle performance is the drag coefficient. However, vehicle development today is performed mostly under controlled settings using wind tunnels and computational fluid dynamics (CFD) with artificially uniform upstream conditions, neglecting real-world effects due to road turbulence from wind and other vehicles. Thus, the drag coefficients computed with these methods might not be representative of the real performance of the car on the road. This might ultimately lead engineers to develop design solutions and aerodynamic devices which, while performing well in idealized conditions, do not perform well on the road. For this reason, it is important to assess the vehicle’s drag as seen in real-world environments. An effort in this direction is represented by using the wind-averaged drag.
2017-03-28
Journal Article
2017-01-0777
Gordon McTaggart-Cowan, Jian Huang, Sandeep Munshi
Abstract Natural gas offers the potential to reduce greenhouse gas emissions from heavy-duty on-road transportation. One of the challenges facing natural gas as a fuel is that its composition can vary significantly between different fuel suppliers and geographical regions. In this work, the impact of fuel composition variations on a heavy-duty, direct injection of natural gas engine with diesel pilot ignition is evaluated. This combustion process results in a predominantly non-premixed gaseous fuel combustion event; as a result, end-gas autoignition (knock) is not a concern. Changes in the fuel composition do still impact the combustion, both through the changes in the chemical kinetics of the reactions and due to changes in the density of the fuel. Increasing concentrations of heavier hydrocarbons, such as ethane or propane, in the fuel lead to higher fuel densities and hence greater fuel mass being injected for a given injection duration.
2017-03-28
Technical Paper
2017-01-0817
Remi Konagaya, Ken Naitoh, Kohta TSURU, Yasuo Takagi, Yuji Mihara
Abstract For various densities of gas jets including very light hydrogen and relatively heavy ones, the penetration length and diffusion process of a single high-speed gas fuel jet injected into air are computed by performing a large eddy simulation (LES) with fewer arbitrary constants applied for the unsteady three-dimensional compressible Navier-Stokes equation. In contrast, traditional ensemble models such as the Reynolds-averaged Navier-Stokes (RANS) equation have several arbitrary constants for fitting purposes. The cubic-interpolated pseudo-particle (CIP) method is employed for discretizing the nonlinear terms. Computations of single-component nitrogen and hydrogen jets were done under initial conditions of a fuel tank pressure of gas fuel = 10 MPa and back pressure of air = 3.5 MPa, i.e., the pressure level inside the combustion chamber after piston compression in the engine.
2017-03-28
Technical Paper
2017-01-0778
Vishnu Vijayakumar, P. Sakthivel, Bhuvenesh Tyagi, Amardeep Singh, Reji Mathai, Shyam Singh, Ajay Kumar Sehgal
Abstract In the light of major research work carried out on the detrimental health impacts of ultrafine particles (<50 nm), Euro VI emission standards incorporate a limit on particle number, of which ultrafine particles is the dominant contributor. As Compressed Natural Gas (CNG) is a cheaper and cleaner fuel when compared to diesel, there has been a steady increase in the number of CNG vehicles on road especially in the heavy duty segment. Off late, there has been much focus on the nature of particle emissions emanating from CNG engines as these particles mainly fall under the ultrafine particle size range. The combustion of lubricant is considered to be the dominant source of particle emissions from CNG engines. Particle emission due to lubricant is affected by the oil transport mechanisms into the combustion chamber which in turn vary with engine operating conditions as well as with the physico chemical properties of the lubricant.
2017-03-28
Technical Paper
2017-01-0782
Qian xiong, Yasuo Moriyoshi, Koji Morikawa, Yasushi takahashi, Tatsuya Kuboyama, Toshio Yamada
Abstract To understand the mechanism of the combustion by torch flame jet in a gas engine with pre-chamber and also to obtain the strategy of improving thermal efficiency by optimizing the structure of pre-chamber including the diameter and number of orifices, the combustion process was investigated by three dimensional numerical simulations and experiments of a single cylinder natural gas engine. As a result, the configuration of orifices was found to affect the combustion performance strongly. With the same orifice diameter of 1.5mm, thermal efficiency with 7 orifices in pre-chamber was higher than that with 4 orifices in pre-chamber, mainly due to the reduction of heat loss by decreasing the impingement of torch flame on the cylinder linear. Better thermal efficiency was achieved in this case because the flame propagated area increases rapidly while the flame jets do not impinge on the cylinder wall intensively.
2017-03-28
Technical Paper
2017-01-0781
Philip Zoldak, Jeffrey Naber
Abstract The increased availability of natural gas (NG) in the United States (US) and its relatively low cost versus diesel fuel has increased interest in the conversion of medium duty (MD) and heavy duty (HD) engines to NG fueled combustion systems. The aim for development for these NG engines is to realize fuel cost savings and increase operating range while reduce harmful emissions and maintaining durability. Traditionally, port-fuel injection (PFI) or premixed NG spark-ignited (SI) combustion systems have been used for light duty LD, and MD engines with widespread use in the US and Europe [1]. However, this technology exhibits poor thermal efficiency and is load limited due to knock phenomenon that has prohibited its use for HD engines. Spark Ignited Direct Injection (SIDI) can be used to create a partially stratified combustion (PSC) mixture of NG and air during the compression stroke.
2017-03-28
Technical Paper
2017-01-0783
Hamid R. Rahai, Yong Lee, Najmeh rahimi, Komal Gada
Abstract The investigation has been divided into two parts. In part one, numerical investigations of the effect of humid air with different levels of humidity on gaseous emissions of a non-premixed combustion have been investigated. This part of the investigation was a feasibility study, focused on how different levels of humidity in the intake air affects the exhaust NO emission. Part two of the investigation was verification of the numerical results with a naturally aspirated engine with natural gas as the fuel. Here, we also investigated the impact of humid air intake on engine’s particulate matter (PM) emission. For the numerical investigations, the non-premixed combustion in a single cylinder was simulated using the presumed probability density function combustion model. Simulations were performed for dry as well as humid intake air for 0%, 15%, and 30% relative humidity (RH).
2017-03-28
Technical Paper
2017-01-1034
Ben Zhao, Liangjun Hu, Abraham Engeda, Harold Sun
As the variable nozzle turbine (VNT) becomes an important element in engine fuel economy and engine performance, improvement of turbine efficiency over wide operation range is the main focus of the research efforts for both the academia and industry in the past decades. It is well known that in a VNT, the nozzle endwall clearance has big impact on the turbine efficiency, especially at small nozzle open positions. However the clearance at hub and shroud wall side may contribute differently to the turbine efficiency penalty. When total height of nozzle clearance is fixed, varying distribution of nozzle endwall clearance at hub and shroud sides is possible to generate different patterns of the clearance leakage flow that has different interaction with and impact on the main flow after exiting the clearances.
2017-03-28
Technical Paper
2017-01-0184
Miyoko Oiwake, Ozeki Yoshiichi, Sogo Obata, Hideaki Nagano, Itsuhei Kohri
Abstract In order to develop various parts and components for hybrid electric vehicles, understanding the effect of their structure and thermal performance on their fuel consumption and cruising distance is essential. However, this essential information is generally not available to suppliers of vehicle parts and components. In this report, following a previous study of electric vehicles, a simple method is proposed as the first step to estimate the algorithm of the energy transmission and then the cruising performance for hybrid electric vehicles. The proposed method estimates the cruising performance using only the published information given to suppliers, who, in general, are not supplied with more detailed information. Further, an actual case study demonstrating application of the proposed method is also discussed.
2017-03-28
Technical Paper
2017-01-0190
Neelakandan Kandasamy, Steve Whelan
Abstract The range of Plug-In Electric Vehicles (EVs) is highly influenced by the electric power consumed by various sub systems, the major part of the power being used for vehicle climate control strategies in order to ensure an acceptable level of thermal comfort for the passengers. Driving range decreases with low temperatures in particular because cabin heating system requires significant amount of electric power. Range also decreases with high ambient temperatures because of the air conditioning system with electrically-driven compressor. Both thermal systems reduce EV driving range under real life operating cycles, which can be a barrier against market penetration. The structure of a vehicle is capable of absorbing a significant amount of heat when exposed to hot climate conditions. 50-70% of this heat penetrates through the glazing and raises both the internal cabin air temperature and the interior trim surface temperature.
2017-03-28
Technical Paper
2017-01-0192
Antti Lajunen
Abstract The energy used for cabin cooling and heating can drastically reduce the operating range of electric vehicles. The energy efficiency and performance of the cabin heating, ventilation and air conditioning (HVAC) system depend on the system configuration and ambient conditions. The presented research investigates the energy efficiency and performance of cabin thermal management in electric vehicles. A simulation model of cabin heating and cooling systems was developed in the AMESim software. Simulations were carried out in the standard test cycles and one real-world driving cycle to take into account different driving behaviors and environments. The cabin thermal management performance was analyzed in relation to ambient temperature, system efficiency and cabin thermal balance. The simulation results showed that the driving range can shorten more than 50% in extreme cold conditions.
2017-03-28
Technical Paper
2017-01-0232
Nizar Khemri, Hao Ying, Joseph Supina, Fazal Syed
Abstract Realistic vehicle fuel economy studies require real-world vehicle driving behavior data along with various factors affecting the fuel consumption. Such studies require data with various vehicles usages for prolonged periods of time. A project dedicated to collecting such data is an enormous and costly undertaking. Alternatively, we propose to utilize two publicly available vehicle travel survey data sets. One is Puget Sound Travel Survey collected using GPS devices in 484 vehicles between 2004 and 2006. Over 750,000 trips were recorded with a 10-second time resolution. The data were obtained to study travel behavior changes in response to time-and-location-variable road tolling. The other is Atlanta Regional Commission Travel Survey conducted for a comprehensive study of the demographic and travel behavior characteristics of residents within the study area.
Viewing 151 to 180 of 16427