Criteria

Text:
Affiliation:
Display:

Results

Viewing 1 to 30 of 86
Technical Paper
2014-04-01
Adam Ing, Ramin Masoudi, John McPhee, Thanh-Son Dao
Abstract Due to rising fuel prices and environmental concerns, Electric Vehicles (EVs) and Hybrid Electric Vehicles (HEVs) have been gaining market share as fuel-efficient, environmentally friendly alternatives. Lithium-ion batteries are commonly used in EV and HEV applications because of their high power and energy densities. During controls development of HEVs and EVs, hardware-in-the-loop simulations involving real-time battery models are commonly used to simulate a battery response in place of a real battery. One physics-based model which solves in real-time is the reduced-order battery model developed by Dao et al. [1], which is based on the isothermal model by Newman [2] incorporating concentrated solution theory and porous electrode theory [3]. The battery models must be accurate for effective control; however, if the battery parameters are unknown or change due to degradation, a method for estimating the battery parameters to update the model is required. A set of manufacturer recommended battery parameters were evaluated using a numerical sensitivity analysis to evaluate their identifiability.
Technical Paper
2014-04-01
Nikky Pathak, Cliff Butcher, Michael Worswick, Erika Bellhouse, Jeff Gao
Abstract New innovations in the field of advanced high strength steels (AHSS) have led to the development of steels with improved stretch-flangeability known as hot-rolled multi-phase (HR) steels. To understand the performance of HR steels, hole expansion tests were conducted on five prototype HR steels and compared with their commercial dual-phase (DP) steel equivalent. A variety of hole edge conditions were considered to study the influence of the shear-affected-zone (SAZ), the surface roughness at the sheared edge and the shear burr orientation. The microstructure of each material was characterized and discussed in relation to its formability for the different edge conditions. It was observed that the bainitic-ferrite microstructure of the HR steels showed superior formability during sheared edge stretching compared to commercial dual-phase steels.
Technical Paper
2014-04-01
Andrew Hall, John McPhee
Abstract Physical rig testing of a vehicle is often undertaken to obtain experimental data that can be used to ensure a mathematical model is an accurate representation of the vehicle under study. Kinematics and Compliance (K&C) testing is often used for this purpose. The relationship between the hard point locations and compliance parameters, and K&C characteristics of a suspension system is complex, and so automating the process to correlate the model to the test data can make the exercise easier, faster and more accurate than hand tuning the model. In this work, such a process is developed. First, the model parameters are adjusted, next a simulation is run, before the results are read and post processed. This automation processed is used in conjunction with an optimization procedure to carry out the K&C correlation. MATLAB scripts are created to modify the model parameters, run simulations and read the results so that MATLAB optimization algorithms can be used to identify the most appropriate suspension parameter values.
Technical Paper
2014-04-01
Dan Kraehling, David Anderson, Michael Worswick, Tim Skszek
Abstract The effect of stress triaxiality on failure strain in as-cast magnesium alloy AM60B is examined. Experiments using one uniaxial and two notched tensile geometries were used to study the effect of stress triaxiality on the quasi-static constitutive response of super vacuum die cast AM60B castings. For all tests, local strains, failure location and specimen elongation were tracked using two-dimensional digital image correlation (DIC) analysis. The uniaxial specimens were tested in two orthogonal directions to determine the anisotropy of the casting. Finite element models were developed to estimate effective plastic strain histories and stress state (triaxiality) as a function of notch severity. It was found that there is minimal, if any, anisotropy present in AM60B castings. Higher stress triaxiality levels caused increases in maximum stress and decreases in elongation and local effective plastic strain at failure. This data will serve as the basis for the development of a damage-based constitutive model.
Technical Paper
2014-04-01
Ramin Masoudi, Hadi Adibi asl, Nasser Lashgarian Azad, John McPhee
Abstract Parameter identification of a math-based spark-ignition engine model is studied in this paper. Differential-algebraic equations governing the dynamic behavior of the engine combustion model are derived using a quasi-dimensional modelling scheme. The model is developed based on the two-zone combustion theory with turbulent flame propagation through the combustion chamber [1]. The system of equations includes physics-based equations combined with the semi-empirical Wiebe function. The GT-Power engine simulator software [2], a powerful tool for design and development of engines, is used to extract the reference data for the engine parameter identification. The models is GT-Power are calibrated and validated with experimental results; thus, acquired data from the software can be a reliable reference for engine validation purposes. Homotopy optimization procedure, in which the original differential equations are modified by coupling the experimental data to the mathematical model using a homotopy parameter and gains, has been utilized in this work to obtain a global minimum for the parameters giving the best match to experiments [3].
Technical Paper
2014-04-01
Shinhoon Kim, John McPhee, Nasser Lashgarian Azad
Abstract A compact sized vehicle that has a narrow track could solve problems caused by vehicle congestion and limited parking spaces in a mega city. Having a smaller footprint reduces the vehicle's total weight which would decrease overall vehicle power consumption. Also a smaller and narrower vehicle could travel easily through tight and congested roads that would speed up the traffic flow and hence decrease the overall traffic volume in urban areas. As an additional benefit of having a narrow track length, a driver can experience similar motorcycle riding experience without worrying about bad weather conditions since a driver sits in a weather protected cabin. However, reducing the vehicle's track causes instability in vehicle dynamics, which leads to higher possibility of rollovers if the vehicle is not controlled properly. A three wheel personal vehicle with an active tilting system is designed in MapleSim. The vehicle is driven by constant rotational input which is applied to the rear wheel.
Technical Paper
2014-04-01
Soheil Mohagheghi fard, Amir Khajepour, Ayyoub Rezaeian, Chris J. Mendes
Abstract This paper seeks to identify the refrigeration load of a hybrid electric truck in order to find the demand power required by the energy management system. To meet this objective, in addition to the power consumption of the refrigerator, the vehicle mass needs to be estimated. The Recursive Least Squares (RLS) method with forgetting factors is applied for this estimation. As an example of the application of this parameter identification, the estimated parameters are fed to the energy control strategy of a parallel hybrid truck. The control system calculates the demand power at each instant based on estimated parameters. Then, it decides how much power should be provided by available energy sources to minimize the total energy consumption. The simulation results show that the parameter identification can estimate the vehicle mass and refrigeration load very well which is led to have fairly accurate power demand prediction. As a result, the energy management system can work to improve the fuel economy of the refrigerator truck.
Technical Paper
2014-04-01
Ehsan Samadani, Leo Gimenez, William Scott, Siamak Farhad, Michael Fowler, Roydon Fraser
Abstract In electrified vehicle applications, the heat generated of lithium-ion (Li-ion) cells may significantly affect the vehicle range and state of health (SOH) of the pack. Therefore, a major design task is creation of a battery thermal management system with suitable control and cooling strategies. To this end, the thermal behavior of Li-ion cells at various temperatures and operating conditions should be quantified. In this paper, two different commercial pouch cells for plug-in hybrid electric vehicles (PHEVs) are studied through comprehensive thermal performance tests. This study employs a fractional factorial design of experiments to reduce the number of tests required to characterize the behavior of fresh cells while minimizing the effects of ageing. At each test point, the effects of ambient temperature and charge/discharge rate on several types of cell efficiencies and surface heat generation is evaluated. A statistical thermal ramp rate model is suggested which enables fast and accurate determination of cell surface temperature and heat generation where the vehicle is started from cold or warm environments at a range of constant currents over the entire state of charge (SOC) range.
Technical Paper
2014-04-01
Ehsan Samadani, Roydon Fraser, Michael Fowler
Abstract Despite significant progress toward application of Li-ion batteries in electric vehicles, there are still major concerns about the range of electric vehicles and battery life. Depending on the climate of the region where the vehicle is in use, auxiliary loads could also play a significant role on the battery performance and durability. In this paper, the effect of air conditioning (AC) load on the electric range and Li-ion battery life is evaluated. For this purpose, a thermodynamic model for the vehicle cabin is developed and integrated to a battery model. The thermodynamic model takes the ambient conditions, solar load, and the vehicle drive cycle as inputs and calculates the instantaneous cabin temperature and humidity. The battery model, which represents a Li-on battery pack installed on a fully electrified Ford Escape 2009, consists of a voltage source in series with a lump resistance, a thermal sub-model, and a degradation sub-model to predict the battery capacity fade. At an initial cabin temperature and a desired set point, the model is capable of predicting the required cooling load and its corresponding required battery power as well as reductions in the vehicle range and battery state of health (SOH).
Technical Paper
2014-04-01
Ehsan Samadani, Siamak Farhad, Satyam Panchal, Roydon Fraser, Michael Fowler
Abstract In this paper, initial results of Li-ion battery performance characterization through field tests are presented. A fully electrified Ford Escape that is equipped by three Li-ion battery packs (LiFeMnPO4) including an overall 20 modules in series is employed. The vehicle is in daily operation and data of driving including the powertrain and drive cycles as well as the charging data are being transferred through CAN bus to a data logger installed in the vehicle. A model of the vehicle is developed in the Powertrain System Analysis Toolkit (PSAT) software based on the available technical specification of the vehicle components. In this model, a simple resistive element in series with a voltage source represents the battery. Battery open circuit voltage (OCV) and internal resistance in charge and discharge mode are estimated as a function of the state of charge (SOC) from the collected test data. It is shown that although the OCV should be measured under no-load condition, still it can be estimated with an acceptable accuracy (∼5%) from the driving data.
Technical Paper
2014-04-01
Amir Khajepour, Ankur Agrawal
A control algorithm is developed for active/semi-active suspensions which can provide more comfort and better handling simultaneously. A weighting parameter is tuned online which is derived from two components - slow and fast adaptation to assign weights to comfort and handling. After establishing through simulations that the proposed adaptive control algorithm can demonstrate a performance better than some controllers in prior-art, it is implemented on an actual vehicle (Cadillac STS) which is equipped with MR dampers and several sensors. The vehicle is tested on smooth and rough roads and over speed bumps.
Technical Paper
2014-04-01
Lu Fan, Bing Zhou, Harry Zheng
In vehicles equipped with conventional Electric Power Steering (EPS) systems, the steering effort felt by the driver can be unreasonably low when driving on slippery roads. This may lead inexperienced drivers to steer more than what is required in a turn and risk losing control of the vehicle. Thus, it is sensible for tire-road friction to be accounted for in the design of future EPS systems. This paper describes the design of an auxiliary EPS controller that manipulates torque delivery of current EPS systems by supplying its motor with a compensation current controlled by a fuzzy logic algorithm that considers tire-road friction among other factors. Moreover, a steering system model, a nonlinear vehicle dynamics model and a Dugoff tire model are developed in MATLAB/Simulink. Physical testing is conducted to validate the virtual model and confirm that steering torque decreases considerably on low friction roads. Finally, simulation results show that the new EPS assist control strategy successfully increases steering effort under slippery conditions without compromising ease of steering, while ensuring that road feel also increases with decreasing in road friction and/or increasing vehicle speed as an additional safety measure.
Article
2014-02-17
Turning circle greatly improved using a model implemented in MapleSim, holding out promise for better active-tilting designs that can improve vehicle maneuverability in congested cities.
Technical Paper
2013-10-14
Joydeep Banerjee, John McPhee, Paul Goossens, Thanh-Son Dao, Hyun-Doo ahn
The analysis of nickel metal hydride (Ni-MH) battery performance is very important for automotive researchers and manufacturers. The performance of a battery can be described as a direct consequence of various chemical and physical phenomena taking place inside the container. In this paper, a physics-based model of a Ni-MH battery will be presented. To analyze its performance, the efficiency of the battery is chosen as the performance measure, which is defined as the ratio of the energy output from the battery and the energy input to the battery while charging. Parametric sensitivity analysis will be used to generate sensitivity information for the state variables of the model. The generated information will be used to showcase how sensitivity information can be used to identify unique model behavior and how it can be used to optimize the capacity of the battery. The results will be validated using a finite difference formulation.
Technical Paper
2013-04-08
Ehsan Samadani, Josh Lo, Michael Fowler, Roydon Andrew Fraser, Leonardo Gimenez
Within the last decade, the automotive industry has made major progress toward the electrification of drive trains and application of electrochemical power sources. Among available storage solutions, Li-ion batteries are considered as the most attractive and are set to be used in the next generation of hybrid and electric vehicles. This is due to their superiority in energy density, power density, and low self-discharge and high cycle life compared to other chemistries. However, there are some limitations associated with Li-ion battery; among them is the operating temperature range. Any deviation from a narrow temperature range may result in low overall performance and potential degradation of the cells. In this paper, impact of ambient temperature on the A123 Li-ion batteries performance is investigated. A123 cells have been tested under constant charge-discharge cycles, hybrid pulse power characterization (HPPC) tests and also standard drive cycle tests. Impact of temperature on the cell capacity, open circuit voltage (OCV) and internal resistance is discussed.
Technical Paper
2013-04-08
Usman Ali, Roydon Andrew Fraser
In this paper, finite element methods are used to analyze the rear subframe for Chevrolet Malibu. Plasticity based material model along with dynamic and static analysis is used. Commercial software LS-DYNA is used to model the subframe. Half model for the subframe is used with the corresponding boundary conditions for our simulations. A material model based on power law is used to account for the material behavior in all simulations. Different loading conditions are used to analyze the subframe under normal driving conditions while the crash results are used to analyze the subframe under vehicle crash. This data is used to compare the performance and safety of the original stock car. A parametric study is also conducted to analyze the effect of material response by changing the material hardening properties. Results show that 1018 mild steel is the most suitable material under crash and normal loading conditions.
Technical Paper
2013-04-08
Paul Goossens, Avesta Goodarzi
A predictive model of a specific vehicle was modeled in the system-level physical modeling tool, MapleSim, for performance and fuel consumption prediction of a full vehicle powertrain, driving a multi-body chassis model with tire models. The project also includes investigation into overall fuel efficiency and effect on vehicle handling for different drive cycles. The goals of this project were to investigate: 1) the relationships between the forces at tire/road interfaces during various drive cycles and the fuel efficiency of a vehicle, and 2) the interaction between the powertrain and the chassis of the vehicle. To accomplish these goals, a complete vehicle model was created in the lumped-parameter physical modeling tool, MapleSim. A great deal of effort has gone into using real parameters and to assure that some mathematical rigour has been employed in its development. This paper presents the development of the model and results, covering: Powertrain (engine, transmission), Chassis (longitudinal, 3D multibody), Steering, and Wheels (tires, brakes).
Technical Paper
2013-04-08
Ryan George, Michael J. Worswick, Duane Detwiler, Jidong Kang
This paper presents the numerical validation of the impact response of a hot formed B-pillar component with tailored properties. A laboratory-scale B-pillar tool is considered with integral heating and cooling sections in an effort to locally control the cooling rate of an austenitized blank, thereby producing a part with tailored microstructures to potentially improve the impact response of these components. An instrumented falling-weight drop tower was used to impact the lab-scale B-pillars in a modified 3-point bend configuration to assess the difference between a component in the fully hardened (martensitic) state and a component with a tailored region (consisting of bainite and ferrite). Numerical models were developed using LS-DYNA to simulate the forming and thermal history of the part to estimate the final thickness and strain distributions as well as the predicted microstructures. A strain-rate-sensitive constitutive model is used to model the as-quenched behavior of the hot-formed components with tailored microstructures.
Technical Paper
2013-04-08
Cliff Butcher, David Anderson, Michael Worswick
Hole expansion of a dual phase steel, DP600, was numerically investigated using a damage-based constitutive law to predict failure. The parameters governing void nucleation and coalescence were identified from an extensive review of the x-ray micro-tomography data available in the literature to ensure physically-sound predictions of damage evolution. A recently proposed technique to experimentally quantify work-hardening and damage in the shear-affected zone is incorporated into the damage model to enable fracture predictions of holes with sheared edges. Finite-element simulations of a hole expansion test with a conical punch were performed for both a punched and milled hole edge condition and the predicted hole expansion ratios are in very good agreement with the experiment values reported by several researchers.
Technical Paper
2013-04-08
Maria El-Zeghayar, Tim Topper, John J. Bonnen
Small crack growth from notches under variable amplitude loading requires that crack opening stress be followed on a cycle by cycle basis and taken into account in making fatigue life predictions. The use of constant amplitude fatigue life data that ignores changes in crack opening stress due to high stress overloads in variable amplitude fatigue leads to non-conservative fatigue life predictions. Similarly fatigue life predictions based on small crack growth calculations for cracks growing from flaws in notches are non-conservative when constant amplitude crack growth data are used. These non-conservative predictions have, in both cases, been shown to be due to severe reductions in fatigue crack closure arising from large (overload or underload) cycles in a typical service load history. The work in this paper is concerned with the derivation of crack closure constants for use in two models; the effective strain-life fatigue model that can be applied to predict fatigue lives for smooth and blunt notched specimens under constant and variable amplitude loading and the effective fatigue crack growth model that can be used to predict fatigue lives of short cracks growing out of notches or flaws under constant and variable amplitude loading.
Article
2013-03-06
Research is aimed at developing the theory and computer algorithms necessary to automatically create engineering models in a mathematical form.
Technical Paper
2012-09-10
Gurhari Preet Singh, Mark Cremasco, Eric Evenchick, Josh Lo, Michael Karpinski-Leydier, Trevor Sabiston, Brandon Walton, Roydon A. Fraser, Michael Fowler
A series plug-in hybrid electric powertrain with all-wheel drive is designed using real-world drive cycles as part of the EcoCAR 2 competition. A stock 2013 Chevrolet Malibu Eco is being re-engineered to reduce fuel consumption and emissions while improving consumer acceptability. Waterloo utilizes a 18.9 kWh A123 energy storage system (ESS), which powers two 105 kW TM4 traction motors. A 2.4 L LE9 General Motors coupled to a 105 kW TM4 motor provides range extending performance. Each step of the design process is discussed, including a novel approach to powertrain selection and controls requirement selection that uses real-world drive cycles. The mechanical integration and unique ESS design is also discussed.
Technical Paper
2012-04-16
Saher Al Shakhshir, Yonxin Wang, Yongtaek Lee, Xianguo Li
Proton exchange membrane fuel cell (PEMFC) is considered to be one of the best clean power sources for transportation application. Water management is a critical issue, conventionally achieved by coating the cell components with the hydrophobic materials. In this work, the effects of one surface-coated cathode gas diffusion layer (GDL) on water removal rate, droplet dynamics, and the cell performance have been studied. The coated GDL is fabricated by coating one side of raw GDL (SpectraCarb 2050-A) with 15 wt. % of polytetrafluoroethylene (PTFE) solution but the other side remains uncoated. The raw GDL is commercial one and made of carbon fiber. The contact angles (θ) on both sides of the coated and raw GDL are measured. The pore size distribution, and capillary pressure are measured for the GDL, studied using the method of standard porosimetry (MSP). Water removal rate is measured by using a 20 ml syringe barrel, wherein a 13 mm diameter GDL token is stuck on the barrel opening. The droplets penetrating through the GDL are visualized via high speed camera to study the droplet dynamics.
Technical Paper
2012-04-16
Seyed Ehsan Samadani, Roydon A. Fraser, Michael Fowler
Due to the high power and energy density and also relative safety, lithium ion batteries are receiving increasing acceptability in industrial applications especially in transportation systems with electric traction such as electric vehicles and hybrid electric vehicles. In this regard, to ensure performance reliability, accurate modeling of calendar life of such batteries is a necessity. In fact, potential failure of Li-ion battery packs remains a barrier to commercialization. Battery pack life is a critical feature to warranty and maintenance planning for hybrid vehicles, and will require adaptive control systems to account for the loss in vehicle range, and loss in battery charge and discharge efficiency. Failure not only results in large replacement costs, but also potential safety concerns such as overheating or short circuiting which may lead to fires. That's why health monitoring, fault detection and end of life prediction capability in battery-equipped systems are of great importance.
Technical Paper
2012-04-16
Joydeep Banerjee, Hadi Adibi asl, Nasser Lashgarian Azad, John McPhee
Torque converters are used as coupling devices in automobile powertrains involving automatic transmissions. Efficient modeling of torque converters capturing various modes of operation is important for powertrain design and simulation, (Hroval and Tobler 1, Ishihara and Emori 2) optimization and control applications. Models of torque converters are available in various commercial simulation packages, Hadi et. al. 3. The information about the effect of model parameters on torque converter performance is valuable for any design operation. In this paper, a symbolic sensitivity analysis of a torque converter model will be presented. Direct differentiation (Serban and Freeman 4) is used to generate the sensitivity equations which results in equations in symbolic form. By solving the sensitivity equations, the effect of a perturbation of the model parameters on the behavior of the system is determined. A parametric importance analysis is performed on the model: the model parameters are arranged according to their effect on the amount loss of energy during the operation of the torque converter.
Technical Paper
2012-04-16
Jin-Yong Luo, Aleksey Yezerets, Cary Henry, Howard Hess, Krishna Kamasamudram, Hai-Ying Chen, William S. Epling
The effects of propylene (C₃H₆) and dodecane (n-C₁₂H₂₆) exposure on the NH₃-based selective catalytic reduction (SCR) performance of two Cu-exchanged zeolite catalysts were investigated. The first sample was a model Cu/beta zeolite sample and the second a state-of-the-art Cu/zeolite sample, with the zeolite material characterized by relatively small pores. Overall, the state-of-the-art sample performed better than the model sample, in terms of hydrocarbon inhibition (which was reduced) and N₂O formation (less formed). The state-of-the-art sample was completely unaffected by dodecane at temperatures lower than 300°C, and only slightly inhibited (less than 5% conversion loss), for standard SCR, by C₃H₆. There was no evidence of coke formation on this catalyst with C₃H₆ exposure. The model sample was more significantly affected by hydrocarbon exposure. With C₃H₆, inhibition is associated with its partial oxidation intermediates adsorbed on the catalyst surface. For example, at 150°C, no C₃H₆ oxidation was observed and no inhibition was noted.
Technical Paper
2011-05-17
Thank-Son Dao, Aden Seaman, John McPhee, Koichi Shigematsu
The recent increase in oil prices and environmental concerns have attracted various research efforts on hybrid electric vehicles (HEVs) which provide promising alternatives to conventional engine-powered vehicles with better fuel economy and fewer emissions. To speed up the design and prototyping processes of new HEVs, a method that automatically generates mathematics equations governing the vehicle system response in an optimized symbolic form is desirable. To achieve this goal, we employed MapleSim T M , a new physical modeling tool developed by Maplesoft Inc., to develop the multi-domain model of a series-HEV, utilizing the symbolic computing algorithms of Maple software package to generate an optimized set of governing equations. The HEV model consists of a mean-value internal combustion engine (ICE), a chemistry-based Ni-MH battery pack, and a multibody vehicle model. Simulations are then used to demonstrate the performance of the developed HEV system. Simulation results show that the model is viable and the number of governing equations is reduced significantly, resulting in a computationally efficient system.
Technical Paper
2011-04-12
Jian Jun Zhu, Amir Khajepour, Ebrahim Esmailzadeh, Alireza Kasaiezadeh
In a conventional vehicle, the longitudinal shocks caused by the road obstacles cannot be effectively absorbed due to the fact that the longitudinal connections between the chassis and wheels are typically very stiff compared with the vertical strut where the regular spring is mounted. To overcome this limitation, a concept design of a planar suspension system (PSS) is proposed. The rather stiff longitudinal linkages are replaced by a spring-damping strut in a PSS so that the vibration along any direction in the wheel plane can be effectively isolated. For a vehicle with such suspension systems, the wheels can move forth and back with respect to the chassis. The wheelbase and load distribution at the front and rear wheels can change as a consequence of the implementation of the PSS on a vehicle. The planar system can induce changes in the vehicle dynamic behavior. This paper presents the overview introduction of a dynamic study of a vehicle with such suspension systems. The simulation results are analyzed and compared with those of a similar conventional vehicle.
Technical Paper
2011-04-12
Mohammad Pournazeri, Amir Khajepour, Amir Fazeli
Significant improvement in fuel consumption, torque delivery and emission could be achieved through flexible control of the valve timings, duration and lift. In most existing electro-hydraulic variable valve actuation systems, the desired valve lift within every engine cycle is achieved by accurately controlling of the solenoid-valve opening interval; however, due to slow response time, precision control of these valves is difficult particularly during higher engine speeds. In this paper a new lift control strategy is proposed based on the hydraulic supply pressure and flow control. In this method, in order to control the peak valve lift, the hydraulic pump speed is precisely controlled using a two-input gearbox mechanism. This eliminates the need for precision control of the solenoid valves opening interval within every cycle. To achieve a smooth control signal, it is worthwhile to control the maximum valve lift within few engine cycles rather than every cycle; therefore, instead of using the governing non-linear differential equations of the mechanism, a novel average model of the system is developed based on energy conservation equations.
Technical Paper
2011-04-12
Xuxian Hou, William S. Epling, Steven J. Schmieg, Wei Li
The performance of a commercial Cu-zeolite SCR catalyst after differing degrees of hydrothermal aging (aged for 72 hours at 500, 700 and 800°C with 10% moisture balanced with air) was studied by spatially resolving different key reactions using gas-phase FTIR measurements. Gases were sampled along a channel at different positions and analyzed using FTIR, which overcomes the interference of water and nitrogen on ammonia concentration detection encountered in standard mass spectrometer-based spatial resolution measurements. The NO:NO₂ concentration ratio was changed so that the standard (NO:NO₂ = 1:0), fast (NO:NO₂ = 1:1) and NO₂ (NO:NO₂ = 0:1) SCR reactions could be investigated as a function of the catalyst's hydrothermal aging extent. In addition, the effects of hydrothermal aging on the activity of NH₃ and NO oxidation were also investigated. Hydrothermal aging had little effect on NO oxidation activity. For standard and fast SCR processes, NOx conversion attained its maximum at 300°C.
Viewing 1 to 30 of 86

Filter

  • Range:
    to:
  • Year: