scholarly journals Analysis of the Driving Altitude and Ambient Temperature Impact on the Conversion Efficiency of Oxidation Catalysts

2021 ◽  
Vol 11 (3) ◽  
pp. 1283
Author(s):  
José Ramón Serrano ◽  
Pedro Piqueras ◽  
Enrique José Sanchis ◽  
Bárbara Diesel
Keyword(s):  
Ambient Temperature ◽  
Conversion Efficiency ◽  
Mass Flow ◽  
Engine Performance ◽  
Oxidation Catalyst ◽  
Ambient Conditions ◽  
Engine Operation ◽  
Temperature Impact ◽  
Conversion Efficiencies ◽  
The Impact

Worldwide emission standards are extending their requirements to cover engine operation under extreme ambient conditions and fill the gap between the type-approval and real driving conditions. The new ambient boundaries affect the engine performance and raw emissions as well as the efficiency of the exhaust aftertreatment systems. This study evaluates the impact of high altitude and low ambient temperature on the light-off temperature and conversion efficiency of an oxidation catalyst. The results are compared in a common range of exhaust mass flow and temperature with the baseline sea-level operation at 20 °C. A reduction of CO and HC conversion efficiencies was found at 2500 m and −7 °C, with a relevant increase of the light-off temperature for both of the pollutants. The analysis of the experimental data was complemented with the use of a catalyst model to identify the causes leading to the deterioration of the CO and HC light-off. The use of the model allowed for identifying, for the same exhaust mass flow and temperature, the contributions to the variation of conversion efficiency caused by the change in engine-out emissions and tailpipe pressure, which are, in turn, manifested in the variation of the reactants partial pressure and dwell time as governing parameters.

Ambient Temperature Impact on Pressurized SOFC Hybrid Systems

2015 ◽  
Author(s):  
Luca Larosa ◽  
Alberto Traverso ◽  
Valentina Zaccaria
Keyword(s):  
Fuel Cell ◽  
Ambient Temperature ◽  
Hybrid System ◽  
Mass Flow ◽  
Electrical Current ◽  
Superior Performance ◽  
Ambient Conditions ◽  
Cell Temperature ◽  
Utilization Factor ◽  
The Impact

In this paper advanced control strategies based on Model Predictive Control (MPC) method are compared against a traditional PID controller in a Gas Turbine Pressurized SOFC hybrid system. A model of the integrated mGT-SOFC hybrid system has been developed to analyze the impact of ambient temperature changes on system performance and dynamic behaviour. Four different MIMO controllers (multi input multi output) based on a linearized system model have been implemented in order to control fuel cell temperature and power with different ambient temperatures. Fuel cell temperature is regulated by manipulating the cell by-pass mass flow, while power is regulated by changing the fuel cell electrical current and fuel mass flow (the fuel utilization factor is kept constant). Load following simulations have been carried out as follows: the same load ramp from 100% to 80% of fuel cell power and back has been set and studied under three different ambient conditions, 263K, 288K and 313K (−10°C, 15°C and 40°C). MPC demonstrated superior performance over the two distributed PID controls, thanks to the better setpoint tracking on the cell temperature, which is particularly evident when the ambient temperature deviates from the nominal condition. This is mainly explained by the capability of MPC in including the effects of non-linearities of the real system.

scholarly journals Experimental and Numerical Testing of Ambient Temperature Impact on Lifespans of Cuffs of Vehicles’ Steering Systems

2020 ◽  
Vol 10 (12) ◽  
pp. 4371
Author(s):  
Radoje Vujadinović ◽  
Vladimir Pajković ◽  
Sreten Simović ◽  
Milanko Damjanović ◽  
Petar Nikčević
Keyword(s):  
Numerical Analysis ◽  
Ambient Temperature ◽  
Steering System ◽  
Ansys Software ◽  
Software Environment ◽  
Numerical Testing ◽  
Northern Areas ◽  
Protective Element ◽  
Temperature Impact ◽  
The Impact

The steering system represents one of the most important systems of active safety in vehicles. The process of a steering system failure usually starts with the failure of its protective element (cuff). Numerous factors influence a cuff’s lifespan, but the research subject of this paper is the impact of ambient temperature. The goal of this research is the experimental verification of the finding that vehicles used in northern areas require more frequent interventions in their steering systems than vehicles used in the south. A simulator performing a motion similar to the work of a cuff during a vehicle’s motion was made for the purpose of the research. A refrigerating chamber where cuffs were tested at temperatures from −4 °C to −20 °C was also made. A numerical analysis, with the ANSYS software environment, was also carried out. The numerical analysis shows that the failure of a cuff could be expected at almost the same point at which it was experimentally proven. Therefore, the failure, namely the breaking of a cuff, is not only a consequence of the material’s fatigue due to a big number of oscillations, but it also depends upon the impact of ambient temperature where the vehicle is used.

Impact of Measurement Uncertainty in the Characteristic Maps of a Turbocharger on Engine Performance

2013 ◽  
Vol 136 (2) ◽  
Author(s):  
Holger Mai ◽  
Mathias Vogt ◽  
Roland Baar ◽  
Andreas Kinski
Keyword(s):  
Measurement Uncertainty ◽  
Process Simulation ◽  
Combustion Engine ◽  
Engine Performance ◽  
Engine Emissions ◽  
Engine Operation ◽  
Power Simulation ◽  
Systematic Uncertainties ◽  
Measurement Results ◽  
The Impact

The main goal of current engine development is to increase power density and efficiency and to minimize engine emissions. The idea is to obtain the desired power output with a highly charged combustion engine in combination with exhaust gas turbocharging and a very small engine displacement, which is known as downsizing. The selection of a turbocharger is based on the maps of the turbine and compressor, which are usually measured on a test bench. They also provide important boundary conditions on the engine process simulation of a supercharged engine with this turbocharger. In general, a very accurate measurement of the characteristic maps is desired to ensure the best possible matching. However, random and systematic errors have an impact on the measurement results. In order to assess the quality of the measured and calculated values, it is necessary to determine the uncertainties of the measurement variables as accurately as possible; particularly, the error propagation in calculating the efficiencies. The uncertainties are based on a systematic uncertainty component of the sensor and the confidence interval. In this way, the measurement uncertainty is estimated by linear and geometric combination of the calculated random and systematic uncertainties. After that, the respective uncertainty contributions and the identification of the relevant parameters that influence the resulting measurement uncertainty are evaluated. Knowing the measurement uncertainties of the characteristic maps of a turbocharger, the influence on engine operation will be determined with a one-dimensional engine process simulation model. Consequently, the determined measurement uncertainty will be applied as a deviation on the efficiencies and will be investigated in a GT POWER simulation. The impact of the measurement uncertainty on the engine performance is shown on the basis of load steps.

scholarly journals Efficiency of solar radiation conversion in photovoltaic panels

2018 ◽  
Vol 10 ◽  
pp. 02014 ◽  
Author(s):  
Sławomir Kurpaska ◽  
Jarosław Knaga ◽  
Hubert Latała ◽  
Jakub Sikora ◽  
Wiesław Tomczyk
Keyword(s):  
Solar Radiation ◽  
Ambient Temperature ◽  
Conversion Efficiency ◽  
Radiation Intensity ◽  
Radiation Energy ◽  
Climatic Conditions ◽  
Ambient Conditions ◽  
Photovoltaic Panels ◽  
Solar Radiation Intensity ◽  
Radiation Conversion

This paper included analysis the conversion efficiency in photovoltaic panels. The tests were done between February and June at a test stand equipped with three commonly used types of photovoltaic panels: poly- and monocrystalline silicon and with semi-conductive layer made of copper (Cu), indium (In), gallium (Ga) and selenium (Se) (CIGS). Five days of each month were selected for a detailed analysis. They were close to the so-called recommended day for calculations in solar power engineering. Efficiency, calculated as the yield of electrical energy in relation to solar radiation energy reaching the panels was made conditional upon solar radiation intensity and ambient temperature. It was found that as solar radiation intensity and ambient temperature increase, the efficiency of solar radiation conversion into electricity is reduced. Correlation dependence was determined for the test data obtained, describing temperature change of panels depending on climatic conditions. It was found that as panel temperature increases, the conversion efficiency is reduced. Within the tested scope of experiment conditions, the efficiency was reduced in the range between 20.1 and 22.8%. The authors also determined the average efficiency values in individual test months together with average ambient conditions of the environment where the process of solar radiation conversion took place.

scholarly journals Assessment of the Effect of Environmental Conditions on Rotorcraft Pollutant Emissions at Mission Level

2017 ◽  
Author(s):  
Jesus Ortiz-Carretero ◽  
Alejandro Castillo Pardo ◽  
Vassilios Pachidis ◽  
Ioannis Goulos
Keyword(s):  
Environmental Conditions ◽  
Engine Performance ◽  
Pollutant Emissions ◽  
Civil Aviation ◽  
Ambient Conditions ◽  
Engine Operation ◽  
Helicopter Rotors ◽  
Helicopter Flight ◽  
Fuel Burn

It is anticipated that the contribution of rotorcraft activities to the environmental impact of civil aviation will increase in the forthcoming future. Due to their versatility and robustness, helicopters are often operated in harsh environments with extreme ambient conditions and dusty air. These severe conditions affect not only the engine operation but also the performance of helicopter rotors. This impact is reflected in the fuel burn and pollutants emitted by the helicopter during a mission. The aim of this paper is to introduce an exhaustive methodology to quantify the influence of the environment in the mission fuel consumption and the associated emissions of nitrogen oxides (NOx). An Emergency Medical Service (EMS) and a Search and Rescue (SAR) mission were used as a case study to simulate the effects of extreme temperatures, high altitude and compressor degradation on a representative Twin-Engine Medium (TEM) weight helicopter, the Sikorsky UH-60A Black Hawk. A simulation tool for helicopter mission performance analysis developed and validated at Cranfield University was employed. This software comprises different modules that enable the analysis of helicopter flight dynamics, powerplant performance and exhaust emissions over a user defined flight path profile. The results obtained show that the environmental effects on mission fuel and emissions are mainly driven by the modification of the engine performance for the particular missions simulated. Fluctuations as high as 12% and 40% in mission fuel and NOx emissions, respectively, were observed under the environmental conditions simulated in the present study.

Homogeneous Charge Compression Ignition Operation With Natural Gas: Fuel Composition Implications

2003 ◽  
Vol 125 (3) ◽  
pp. 837-844 ◽  
Author(s):  
J. Hiltner ◽  
R. Agama ◽  
F. Mauss ◽  
B. Johansson ◽  
M. Christensen
Keyword(s):  
Natural Gas ◽  
Compression Ratio ◽  
Homogeneous Charge Compression Ignition ◽  
Engine Performance ◽  
Fuel Composition ◽  
Primary Concern ◽  
Compression Ignition ◽  
Engine Operation ◽  
The Impact ◽  
Homogeneous Charge

Homogeneous charge compression ignition (HCCI) is a potentially attractive operating mode for stationary natural gas engines. Increasing demand for efficient, clean burning engines for electrical power generation provides an opportunity to utilize HCCI combustion if several inherent difficulties can be overcome. Fuel composition, particularly the higher hydrocarbon content (ethane, propane, and butane) of the fuel is of primary concern. Fuel composition influences HCCI operation both in terms of design, via compression ratio and initial charge temperature, and in terms of engine control. It has been demonstrated that greater concentrations of higher hydrocarbons tend to lower the ignition temperature of the mixture significantly. The purpose of this paper is to demonstrate, through simulation, the effect of fuel composition on combustion in HCCI engines. Engine performance over a range of fuels from pure methane to more typical natural gas blends is investigated. This includes both the impact of various fuels and the sensitivity of engine operation for any given fuel. Results are presented at a fixed equivalence ratio, compression ratio, and engine speed to isolate the effect of fuel composition. Conclusions are drawn as to how the difficulties arising from gas composition variations may affect the future marketability of these engines.

Evaluating Gas Turbine Performance Using Machine-Generated Data: Quantifying Degradation and Impacts of Compressor Washing

2016 ◽  
Vol 138 (12) ◽  
Author(s):  
Uyioghosa Igie ◽  
Pablo Diez-Gonzalez ◽  
Antoine Giraud ◽  
Orlando Minervino
Keyword(s):  
Gas Turbine ◽  
Measurement Data ◽  
Engine Performance ◽  
Large Data ◽  
Simulation Software ◽  
Engine Operation ◽  
Compressor Inlet ◽  
Data Points ◽  
Global And Local ◽  
The Impact

Gas turbine (GT) operators are often met with the challenge of utilizing and making meaning of the vast measurement data collected from machine sensors during operation. This can easily be about 576 × 106 data points of gas path measurements for one machine in a base load operation in a year, if the width of the data is 20 columns of measured and calculated parameters. This study focuses on the utilization of large data in the context of quantifying the degradation that is mostly related to compressor fouling, in addition to investigations on the impact of offline and online compressor washing. To achieve this, four GT engines operating for about 3.5 years with 51 offline washes and 1184 occasions of online washes were examined. This investigation includes different wash frequencies, liquid concentrations, and one engine operation without online washing (only offline). This study has involved correcting measurement data not only just with compressor inlet temperatures (CITs) and pressures but also with relative humidity (RH). turbomatch, an in-house GT performance simulation software has been implemented to obtain nondimensional factors for the corrections. All of the data visualization and analysis have been conducted using tableau analytics software, which facilitates the investigation of global and local events within an operation. The concept of using of handles and filters is proposed in this study, and it demonstrates the level of insight to the data and forms the basis of the outcomes obtained. This work shows that during operation, the engine performance is mostly deteriorating, though to varying degrees. Online washing also showed an influence on this, reducing the average degradation rate each hour by half, when compared to the engine operating only with offline washing. Hourly marginal improvements were also observed with an increased average wash frequency of nine hours and a similar outcome obtained when the washing solution is 2.3 times more concentrated. Clear benefits of offline washes are also presented, alongside the typically obtainable values of increased power output after a wash, also in relation to the number of operating hours before a wash.

Durability Testing of Biomass Based Oxygenated Fuel Components in a Compression Ignition Engine

2017 ◽  
Author(s):  
Marc E. Baumgardner ◽  
Arunachalam Lakshminarayanan ◽  
Daniel B. Olsen ◽  
Matthew A. Ratcliff ◽  
Robert L. McCormick ◽  
...  
Keyword(s):  
Diesel Fuel ◽  
Fuel Injection ◽  
Engine Performance ◽  
Engine Oil ◽  
Long Term Effects ◽  
Compression Ignition Engine ◽  
Engine Operation ◽  
Minimal Impact ◽  
Carbon Buildup ◽  
The Impact

Blending cellulosic biofuels with traditional petroleum-derived fuels results in transportation fuels with reduced carbon footprints. Many cellulosic fuels rely on processing methods that produce mixtures of oxygenates which must be upgraded before blending with traditional fuels. Complete oxygenate removal is energy-intensive and it is likely that such biofuel blends will necessarily contain some oxygen content to be economically viable. Previous work by our group indicated that diesel fuel blends with low levels (<4%-vol) of oxygenates resulted in minimal negative effects on short-term engine performance and emissions. However, little is known about the long-term effects of these compounds on engine durability issues such as the impact on fuel injection, in-cylinder carbon buildup, and engine oil degradation. In this study, four of the oxygenated components previously tested were blended at 4%-vol in diesel fuel and tested with a durability protocol devised for this work consisting of 200 hrs of testing in a stationary, single-cylinder, Yanmar diesel engine operating at constant load. Oil samples, injector spray patterns, and carbon buildup from the injector and cylinder surfaces were analyzed. It was found that, at the levels tested, these fuels had minimal impact on the overall engine operation, which is consistent with our previous findings.

scholarly journals Optimization of a Mixed Refrigerant Based H2 Liquefaction Pre-Cooling Process and Estimate of Liquefaction Performance with Varying Ambient Temperature

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6090
Author(s):  
Steven Jackson ◽  
Eivind Brodal
Keyword(s):  
Energy Consumption ◽  
Ambient Temperature ◽  
Heat Sink ◽  
Design Parameters ◽  
Ambient Conditions ◽  
Cooling Process ◽  
Transportation Capacity ◽  
Liquefaction Process ◽  
The Impact ◽  
Heat Sink Temperature

Hydrogen used as an energy carrier can provide an important route to the decarbonization of energy supplies, but realizing this opportunity will require both significantly increased production and transportation capacity. One route to increased transportation capacity is the shipping of liquid hydrogen, but this requires an energy-intensive liquefaction step. Recent study work has shown that the energy required in this process can be reduced through the implementation of new and improved process designs, but since all low-temperature processes are affected by the available heat-sink temperature, local ambient conditions will also have an impact. The objective of this work is to identify how the energy consumption associated with hydrogen liquefaction varies with heat-sink temperature through the optimization of design parameters for a next-generation mixed refrigerant based hydrogen liquefaction process. The results show that energy consumption increases by around 20% across the cooling temperature range 5 to 50 °C. Considering just the range 20 to 30 °C, there is a 5% increase, illustrating the significant impact ambient temperature can have on energy consumption. The implications of this work are that the modelling of different liquified hydrogen based energy supply chains should take the impact of ambient temperature into account.

The Challenges of Turbocharger Matching for North American Freight Locomotives

2019 ◽  
Author(s):  
Thomas Lavertu ◽  
Matthew Hart ◽  
Christopher Homison ◽  
Preeti Vaidya
Keyword(s):  
North American ◽  
Engine Performance ◽  
Ambient Air ◽  
Ambient Conditions ◽  
Efficient Operation ◽  
Engine Efficiency ◽  
Air Temperatures ◽  
Wide Range ◽  
The Impact ◽  
Operating Points

Abstract Engine development is centered on developing a solution for best performance while meeting emissions and operational requirements. This will lead to a tradeoff between engine efficiency and emissions across a wide range of load and ambient operating points. Proper airflow to the engine through turbocharger matching is critical to ensure efficient operation and to meet emissions. This study addresses the challenges of turbocharger matching for vehicle advanced emissions control using a North American freight locomotive application as an example. The airflow trends in moving across the various operating points will be shown along with the impact on both the turbocharger and engine performance. First, the airflow trends across the locomotive load set points will be discussed along with the performance and emissions tradeoffs to meet required airflows. Results on the impact on turbocharger performance such as speed will be shown along with the engine efficiency and emissions implications. Next, the ambient operating requirements for a locomotive will be reviewed and the impact on turbocharger matching. Locomotives operate in a wide range of ambient conditions, including altitudes up to 3,050 meters and across ambient air temperatures ranging from −40 °C to well over 38 °C (including higher temperature operation). This thermal swing provides stress on the turbocharger to efficiently deliver the necessary airflow across all conditions. Trends in turbocharger performance will be reviewed and discussed across this range of ambient conditions. In addition, challenges unique to locomotive applications, such as unventilated tunnel operation and vibrational loading, will be reviewed. Finally, potential for advanced technologies such as variable geometry turbines and their applicability to locomotive operation will be discussed.

Sign in / Sign up

Export Citation Format

Share Document