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Techniques for the design of exhaust manifolds with pulse convertersNichols, J. R. January 1984 (has links)
No description available.
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Analytical applications of the peroxyoxalate chemiluminescence reactionSanders, Matthew Graham January 1999 (has links)
The overall objectives of this thesis were to investigate the potential of the peroxyoxalate chemiluminescence (POOL) reaction for the quantitative detection of target analytes in non-aqueous matrices and to compare quantitative performance with fluorescence detection. The target analytes investigated were polycyclic aromatic hydrocarbons (PAHs) and aliphatic amines. These were selected as an important class of compounds in engine exhaust emissions and a detergent additive in diesel fuel respectively. Chapter one outlines the challenges of analysing petroleum products and engine exhaust emissions and discusses the potential of luminescence techniques, particularly chemiluminescence (CL), for the quantification of trace components. The chapter also reviews the technique of flow injection (FT) as a means of sample delivery for CL detection and as a potential technique for field deployment. Liquid chromatography techniques are described as a means of separation of complex matrices, e.g. fuels and engine exhaust particulates, in the laboratory prior to CL detection. The luminescence properties of several PAHs were investigated in Chapter Two. Optimum excitation and emission wavelengths for eleven PAHs in four different solvents were determined using a batch fluorescence technique. A FI approach was used to determine PAH concentrations using fluorescence and POCL detection. Two aryl oxalates; bis(2,4-dinitophenyl)oxalate and bis(2,4,6-trichlorophenyl)oxalate were compared for their suitability for PAH determinations and an investigation of the key variables (e.g. concentration of aryl oxalate and hydrogen peroxide, mobile phase composition and pH) affecting POCL was performed. Recommendations for the optimum conditions for the determination of PAHs by POCL detection were determined, A comparison between a photodiode based detection device and a low power (12V) photomultiplier tube was also described. In Chapter Three the procedure of using POCL detection as a post column liquid chromatography (LC) detector for PAHs has been considered. The performance of the POCL detection system was compared with wavelength programmed fluorescence. Both reversed and normal phase LC was investigated and the suitability of POCL detection with each approach was discussed. Additionally the procedure for the LC separation and analysis of SRM 1649 (Urban Dust/Organics) and SRM 1650 (Diesel Particulate Matter) was described. The relative performance of fluorescence and CL detection are discussed. Chapter four describes the principles of multivariate calibration of spectrophotometric data, and three commonly applied techniques (PCR, PLSI and PLS2). Fluorescence data was obtained for synthetic mixtures of PAHs containing two, three, four and five components. A procedure whereby individual spectra were 'glued' together before undergoing data analysis has been developed and the results obtained discussed. POCL emission spectra for five PAHs were acquired using a two-dimensional charge coupled device (CCD). The sensitivity of the CCD system toward POCL detection of PAHs and a multivariate investigation using benzo[a]pyrene and benzo[k]fluoranthene has been described. The potential of the fluorescence and CL approaches used has been discussed. Chapter five describes the aryl oxalate sulphorhodamine-101 CL reaction and its application to the determination of amines. A FI optimisation of the reaction parameters is presented together with some quantitative data for the detection of a homologous series of amines and dodecylamine (a commonly added detergent compound in diesel fuels). The application of the technique toward the detection of dodecylamine in a diesel fuel matrix and the potential as a field deployable technique was also considered.
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Konstrukce HHO generátoru / Design of HHO generatorGašperec, Michal January 2012 (has links)
The subject of this Master Thesis is construction of hydrogen generator for automotive industry. The objective is to design system which is able to produce required amount of gas. The master thesis includes basic analysis of situation, mathematical equations of electrolytic process and procedure of mechanical design according required power of generator. The next part is design of power control system of hydrogen generator based on informations from automobile. The last part describes power supply of whole system with electric energy. The output of the Master Thesis is the whole design of hydrogen generator including sensor system and control system. The thesis also includes suggestions for next improvements and research.
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Structural-Acoustic Analysis and Optimization of Embedded Exhaust-Washed StructuresVogel, Ryan N. 31 July 2013 (has links)
No description available.
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No/Nox Removal In Diesel Engine Exhaust Under Different Energizations And Reactor ConfigurationsKumar, Bijendra 01 1900 (has links)
In India, with the increase in the number of industries and vehicles the environment is getting more and more polluted. More than industries it is the rapid growth of vehicles which causes serious environmental crisis in the form of air pollution and has become alarming particularly in cities. The industrial and vehicular growth cannot be neglected, as the country’s economic and social well being is largely dependent on them. But this should not come at the cost of our health and eco system. The industrial and vehicular emissions must be controlled in order to keep our air clean. Continued efforts in this direction are being taken up across the globe to investigate an efficient and economical technique.
There are many air pollutants being emitted from both natural and manmade sources. The major air pollutants identified as hazardous to human health are nitrogen oxides (NOx), carbon monoxide (CO), particulate matter (PM), volatile organic compounds (VOC), and sulfur dioxides (SOx). Among these, nitrogen oxides are considered to be difficult to remove. The sources of NOx are thermal power plants, stationary and mobile diesel engines, gasturbine engine, ironore sintering plants and various other smallscale utilities. There are conventionally available technologies to remove NOx such as chemical scrubbing, catalysis etc. But these techniques are either difficult to operate or do not bring down the level of NOx to the required norms imposed by the government. The failure of conventional techniques to remove NOx to the expected limit led to the development of alternative nonconventional techniques. Prominent among these new alternative techniques is electric discharge plasma, where the gas is partially ionized and temperature of electrons is considerably higher than that of ions and background gas molecules.
Diesel engines are getting popular due to their inherent merits and their number is increasing considerably. Unfortunately, the exhaust of diesel engine being complex with high oxygen content makes the existing pollution control techniques insufficient particularly with regard to removal of NOx. So there is a need for investigating better technology which can effectively abate the pollutants from diesel engine exhaust. Electric Discharge plasma is one such alternative technique which has been very successful in large volumes of flue gas cleaning and hence, its potential is being explored in the cleaning of small volumes of vehicular exhausts, in particular, diesel engine exhaust.
In the present work we investigated the relative performance of different electric discharge plasma reactors, with different type of voltages like AC, DC and pulse. The reactors were evaluated for NOx removal efficiency and NO conversion. This research work is a feasibility study to find whether electric discharge plasma can be used more effectively as an alternative technology for the after treatment of diesel engine exhaust in cascade with some cheaper adsorbents, if necessary.
The scope of this qualitative experimental study can briefly be summarized as below:
. • To study different reactors for NO conversion and NOx removal
. • To study the effect of dielectric pellets in enhancing the radical production which in turn will have a bearing on the chemical reactions
. • To study the effect of different types of voltages on the cleansing process
. • To propose an efficient reactor system subject to the experimental conditions studied.
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Acoustic Source Characterization Of The Exhaust And Intake Systems Of I.C. EnginesHota, Rabindra Nath 07 1900 (has links)
For an engine running at a constant speed, both exhaust and intake processes are periodic in nature. This inspires the muffler designer to go for the much easier and faster frequency domain modeling. But analogous to electrical filter, as per Thevenin’s theorem, the acoustic filter or muffler requires prior knowledge of the load-independent source characteristics (acoustic pressure and internal impedance), corresponding to the open circuit voltage and internal impedance of an electrical source. Studies have shown that it is not feasible to evaluate these source characteristics making use of either the direct measurement method or the indirect evaluation method. Hence, prediction of the radiated exhaust or intake noise has been subject to trial and error.
Making use of the fact that pressure perturbation in a duct is a superposition of the forward moving wave and the reflected wave, a simple hybrid approach has been proposed making use of an interrelationship between progressive wave variables of the linear acoustic theory and Riemann variables of the method of characteristics. Neglecting the effect of nonlinearities, reflection of the forward moving wave has been duly incorporated at the exhaust valve. The reflection co-efficient of the system downstream of the exhaust valve has been calculated by means of the transfer matrix method at each of the several harmonics of the engine firing frequency. This simplified approach can predict exhaust noise with or without muffler for a naturally aspirated, single cylinder engine. However, this proves to be inadequate in predicting the exhaust noise of multi-cylinder engines. Thus, estimation of radiated noise has met only limited success in this approach.
Strictly speaking, unique source characteristics do not exist for an IC engine because of the associated non-linearity of the time-varying source. Yet, a designer would like to know the un-muffled noise level in order to assess the required insertion loss of a suitable muffler. As far as the analysis and design of a muffler is concerned, the linear frequency-domain analysis by means of the transfer matrix approach is most convenient and time saving. Therefore, from a practical point of view, it is very desirable to be able to evaluate source characteristics, even if grossly approximate. If somehow it were possible to parameterize the source characteristics of an engine in terms of basic engine parameters, then it would be possible to evaluate the un-muffled noise before a design is taken up as a first approximation. This aspect has been investigated in detail in this work. A finite-volume CFD (one dimensional) model has been used in conjunction with the two-load or multi-load method to evaluate the source characteristics at a point just downstream of the exhaust manifold for the exhaust system, and upstream of the air filter (dirty side) in the case of the intake system. These source characteristics have been extracted from the pressure time history calculated at that point using the electro-acoustic analogy. Systematic parametric studies have yielded approximate empirical expressions for the source characteristics of an engine in terms of the basic engine parameters like engine RPM, capacity (swept volume or displacement), air-fuel ratio, and the number of cylinders. The effect of other parameters has been found to be relatively insignificant.
Unlike exhaust noise, the intake system noise of an automobile cannot be measured because of the proximity of the engine at the point of measurement. Besides, the intake side is associated with turbocharger (booster), intercooler, cooling fan, etc., which will make the measurement of the intake noise erroneous. From the noise radiation point of view, intake noise used to be considered to be a minor source of noise as compared to the exhaust noise. Therefore, very little has been done or reported on prediction of the intake noise as compared to the exhaust noise. But nowadays, with efficient exhaust mufflers, the un-muffled intake noise has become a contributing factor to the passenger compartment noise level as a luxury decisive factor. Therefore, in this investigation both the intake and the exhaust side source characteristics have been found out for the compression ignition as well as the spark ignition engines. Besides, in the case of compression ignition engines, typical turbocharged as well as naturally aspirated engines have been considered.
One of the inputs to the time-domain simulation is the intake valve and exhaust valve lift histories as functions of crank angle. It is very cumbersome and time-consuming to measure and feed these data into the program. Sometimes, this data is not available or cannot be determined easily. So, a generalized formula for the valve lift has been developed by observing the valve lift curves of various engines. The maximum exhaust valve lift has been expressed as a function of the swept volume of the cylinder. This formulation is not intended for designing a cam profile; it is for the purpose of determining approximate thermodynamic quantities to help a muffler designer for an initial estimation. It has also been observed during the investigation that from the acoustic point of view, sometimes it is better to open the exhaust valve a little earlier, but very slowly and smoothly, and keep it open for a longer time.
Although the exact source characteristics for an automobile engine cannot be determined precisely, yet the values of source characteristics calculated using this methodology have been shown to be reasonably good for approximate prediction of the un-muffled noise as well as insertion loss of a given muffler. The resultant empirical expressions for the source characteristics enable the potential user to make use of the frequency-domain cum-transfer matrix approach throughout; the time consuming time-domain simulation of the engine exhaust source is no longer necessary. Predictions of the un-muffled sound pressure level of automotive engines have been corroborated against measured values as the well as the full scale time-domain predictions making use of a finite-volume software.
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Electric Discharge Plasma Promoted Adsorption/Catalysis, For Removal Of NOx, HC And CO From An Actual Diesel Engine ExhaustSrinivasan, A D 08 1900 (has links) (PDF)
No description available.
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Dielectric Barrier Discharge Initiated NOx Abatement In Diesel Engine Exhaust : Towards Achieving Higher Removal EfficiencyMohapatro, Sankarsan 07 1900 (has links) (PDF)
In the last few decades India has advanced socioeconomically due to the rapid growth of industries and automobile sector. This in turn increases the use of fossil fuel and diesel. The atmosphere gets polluted due to the harmful substances, which comes from the burning of fuel. These pollutants can be in the form of gaseous, liquid or solid particulate. Diesel engines, the major source of power in industries and automobiles, play a significant part in causing air pollution. The major pollutants in diesel exhaust are oxides of nitrogen (NOX), sulphur dioxide (SO2), carbon monoxide (CO), hydrocarbons (HC), particulate matter (PM), volatile organic compounds (VOC), aldehydes and alcohols. Due to the heavy consumption of diesel as a fuel there is an urgent need to control diesel exhaust.
Diesel exhaust is a complex mixture of several gases and fine particles (commonly known as soot) that contains more than 40 toxic air contaminants. Amongst the gaseous pollutants in diesel exhaust, the major concern and a challenging task is to control oxides of nitrogen, commonly referred to as NOX as it is the major contributor for acid rain, photochemical smog etc. Successful control of emissions from diesel engines is yet to be achieved. The conventional techniques which are available to control emission now are either difficult to operate or does not satisfy the stringent emission standards. This has made the researchers throughout the world to find an alternative and effective non-conventional after treatment technique to reduce diesel engine emission. The failure of conventional techniques lead to the development of non-conventional techniques such as high voltage electric discharge based plasma which has already been proved to be economical and highly efficient in industrial
electrostatic precipitators.
Electric discharge plasma or non-thermal plasma produce energetic electrons which react with background molecules in flue gas leading to active species such as radicals. These radicals being chemically active selectively react with the harmful pollutants facilitating their removal/reduction.
The present thesis work is an attempt to provide a technical solution to achieve
higher removal efficiencies of oxides of nitrogen in the backdrop of shortcomings that exist in conventional technologies to do so. The current thesis describes the research in four stages: (i) studies on NOX removal from diesel exhaust by cross-flow DBD reactor, where design and fabrication of cross-flow DBD reactor, exhaust treatment using cross-flow DBD reactor and exhaust treatment with cascaded plasma-adsorbent technique is described (ii) studies on NOX removal from diesel exhaust by compact discharge plasma sources, where design and fabrication of high frequency high voltage AC (HVAC) using old television flyback transformer, Design and fabrication of high voltage pulse (HVPulse) using automobile ignition coil, exhaust treatment with both HVPulse and HVAC and exhaust treatment with cascaded plasma-adsorbent technique is described (iii) studies on NOX removal from diesel exhaust using solar powered discharge plasma source is described (iv) studies on the NOX removal from diesel exhaust using red mud, where exhaust treatment with red mud and Exhaust treatment cascaded plasma-red mud is covered. The results have been discussed in light of enhancing the NOX removal efficiency for stationary and automobile engine exhausts.
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Modelling the effect of condensation and evaporation of water on the transient temperatures inside the exhaust system of an IC engine during a cold startHaworth, Leanne 03 1900 (has links)
Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2010. / AFRIKAANSE OPSOMMING:Die navorsing wat hier uiteengesit word ondersoek die hipotese dat kondensasie
en die gevolglike verdamping van water wat teenwoordig is in die uitlaatgas van
‘n binnebrandenjin, plaasvind in die gedeeltes van die uitlaatstelsel tussen die
uitlaatklep en die katalitiese-omsetter se uitlaat. Daar word verder veronderstel
dat hierdie tweefasevloeieffekte die tydafhanklike temperatuurprofiele in die
uitlaatstelsel beïnvloed, wat moontlik kan lei tot ‘n vertraging in die tydsduur vir
die katalitiese omsetter om temperature van 200-300 °C te bereik, wat nodig is om
noemenswaardige omsetting te bewerkstellig.
Om hierdie veronderstelling te evalueer is ‘n tydafhanklike, eendimensionele
wiskundige model van die termo-vloei gedrag in die uitlaatstelsel gedurende ‘n
koue inwerktreeding, insluitende vogtigheidseffekte, opgestel en opgelos deur van
‘n rekenaaralgoritme gebruik te maak. Warmte- en massaoordragsteorie was
gebruik om die ongestadigde massa-, energie- en
momentumbehoudsvergeleikings te formuleer. Die tweefasige vogeffekte was
gemodelleer deur gebruik te maak van die verhouding tussen warmte- en
massaoordrag, wat verdamping en heterogeniese kondensasie (die kondensasie
van damp teen die pypwand) voorspel as gevolg van die dampdrukgradient tussen
die grootmaat damp en die versadigde damp by die oppervlak van die
vloeistoffilm. Homogene kondensasie (die kondensasie van vloeistof in die vorm
van druppels in die dampstroom) was ook in aanmerking geneem indien die
grootmaatgas temperatuur onder die versadigingstemperatuur van die
grootmaatdamp gedaal het.
’n Eksperimentele ondersoek was gedoen deur van twee enjins gebruik te maak,
’n 1.6 L Volkswagen Bora en ’n 1.6 L Ford RoCam, in die toetsselle van Cape
Advanced Engineering Pty (Ltd). Om die gastemperature so akkuraat moontlik te
meet, was spesiale radiasiegeskermde sensore met vinnige reaksietyd ontwerp en
installer in die pypseksies van die uitlaatstelsels van beide enjins. Die geskermde
sensore het temperature van tot 50 °C hoër as konvensionele termokoppels in
dieselfde areas gemeet. Dit is in koers is met resultate wat deur die
foutbeperkingsteorie, geassosieer met die meet van temperature in vloeïende gas
in uitlaatstelsels, voorspel word.
Vergelyking van die numeriese simulasie met die eksperimenteel gemete
temperature het aangedui dat in dele van die uitlaatstelsel voor die katalitieseomsetter,
die vog min uitwerking het op die termiese gedrag van die stelsel. In
hierdie gedeeltes is die konveksie warmte-oordrag dominant. In die katalitieseomsetter
was die vogeffekte invloedryk. Die eksperimentele resultate toon ‘n
duidelike vroeë toename in die gastemperature, gevolg deur ‘n tydperk van
konstante temperature by nagenoeg die versadigingstemperatuur van die
grootmaatdamp (verwys na as die temperatuurplato) by die katalitiese-omsetter se
kern en uitlaat. Die numeries gesimuleerde gastemperature het ook hierdie gedrag
getoon, maar ‘n baie hoë en skerp piek by die begin van die plato het voorgekom. Hierdie piek was nie te sien by die eksperimentele resultate nie en is toegeskryf
aan nie-ewewigstoestande in die verdampingsproses, wat aandui dat die tempo
van verdamping wat deur die massa-oordragmodel voorspel word te hoog is vir
die model en dat dit verfyn moet word. Verdere ondersoek van die invloed van
die individuele massa-oordragprosesse het getoon dat die homogene kondensasie
die dominante proses is in die vorming van vloeistof in die katalitiese-omsetter.
Heterogeniese kondensasie het plaasgevind, maar ‘n kleiner massa vloeistof is
produseer. Die maksimum hoeveelheid vloeistof wat voorspel is om in die
katalitiese-omsetter te vorm was 12 g/cm wat gelykstaande is aan ‘n film van
0.05.mm dik indien eweredig versprei oor die binneoppervlak van die monoliet.
Daar was in die simulasie gevind dat beide verdamping en kondensasie benodig
word om die temperatuurplato te simuleer, vanwaar die gevolgtrekking gemaak
kan word dat beide prosesse wel plaasvind en dat die eerste stelling in die
oorspronklike hipotese wel geldig is. Daar was egter teen die einde van die
toetsperiode gevind dat beide temperature wat met en sonder vogeffekte simuleer
was, die eksperimentele temperature nagevolg het, wat aandui dat die invloed van
vog beperk is tot die vroeë stadiums van die katalitiese-omsetter se
opwarmingstydperk. Die tweede gedeelte van die hipotese wat veronderstel dat
die voggedrag ‘n vertraging in die tydsduur om omsetting te bewerkstellig
veroorsaak, is dus bevind om ongeldig te wees.
Die wiskundige model wat opgestel is tydens die ondersoek is weens
noodsaaklikheid ‘n vereenvoudigde simulasie van komplekse termo-vloei
prosesse. Dit dien as nuttige grondwerk vir verdere in-diepte ondersoeke en
afronding van die teorie met betrekking tot voggedrag en die uitwerking daarvan
op die tydsafhanklike temperature in ‘n uitlaatstelsel. / ENGLISH ABSTRACT: The research presented here investigates the hypothesis that condensation and
subsequent evaporation of water vapour present in the exhaust gas of an internal
combustion engine occur in the sections of the exhaust system between the
exhaust port and the catalytic converter exit. It is further hypothesised that these
two-phase moisture effects influence the transient temperature profiles in the
exhaust system, and potentially cause a delay in the time it takes for the catalytic
converter to reach temperatures of 200-300 °C, which are required for light-off to
occur.
In order to evaluate this hypothesis a transient, one-dimensional mathematical
model of the thermo-fluid behaviour in the exhaust system during a cold start,
including moisture effects, was created and solved by means of a computer
algorithm. Heat and mass transfer theory was used to formulate the unsteady
conservation equations for mass, energy and momentum. The two phase moisture
effects were modelled using the analogy between heat and mass transfer, which
predicts evaporation and heterogeneous condensation (the condensation of vapour
against the pipe wall) due to a vapour pressure gradient between the bulk vapour
and a saturated vapour at the surface of the liquid film. Homogeneous
condensation (the condensation of liquid in the form of droplets in the gas stream)
was also accounted for if the bulk gas temperature dropped below the bulk vapour
saturation temperature.
An experimental investigation was performed using two engines, a 1.6.L
Volkswagen Bora and a 1.6.L Ford RoCam, in the test cells of Cape Advanced
Engineering Pty (Ltd). In order to measure the gas temperatures as accurately as
possible specialised radiation shielded sensors with fast time response were
designed and installed in the pipe sections of the exhaust systems of both engines.
The shielded sensors measured temperatures up 50 °C higher than the
conventional thermocouples installed at the same positions, which is in keeping
with the results predicted by the theory governing errors associated with
temperature measurement in the flowing gas in the exhaust system.
Comparison of the numerically simulated and experimentally measured
temperatures indicated that in the sections of the exhaust system leading up to the
catalytic converter the moisture has little influence on the temperature behaviour
of the exhaust system. In these sections the convective heat transfer is dominant.
In the catalytic converter the moisture effects were found to be influential. The
experimental results clearly show an early rise in the gas temperatures, followed
by a period of constant temperature at approximately the saturation temperature of
the bulk vapour (referred to as the temperature plateau) at the catalytic converter
mid-bed and exit. The numerically simulated gas temperatures also exhibited this
plateau, but an initial very high and sharp peak in the simulated gas temperatures
occurred at the start of the plateau. This was not seen in the experimental results
and is attributed to non-equilibrium in the evaporation process, indicating that the rate of evaporation predicted by the mass transfer model used is too high for this
application and that the model needs to be refined. Further investigation of the
influence of the individual mass transfer processes indicated that the
homogeneous condensation is the dominant process in the formation of liquid in
the catalytic converter. Heterogeneous condensation was found to occur, but
produced a smaller mass of liquid. The maximum amount of liquid predicted to
form in the catalytic converter was 12 g/cm, which translates to a film 0.05 mm
thick if evenly distributed over the inner surface of the monolith.
In the simulation it was found that both evaporation and condensation are needed
in order to simulate the temperature plateau, from which it was concluded that
both these processes do occur and the first statement in the original hypothesis is
valid. However, by the end of the test period temperatures simulated both with or
without the moisture effects closely approached the final temperatures of the
experimental investigation, indicating that the influence of the moisture is limited
to the early stages of the catalytic converter warm-up. The second part of the
hypothesis, postulating that the moisture behaviour caused a delay in the time
taken to reach light-off temperature, is therefore concluded to be invalid.
The mathematical model constructed in this research is by necessity a simplified
solution to complex thermo-fluid processes. It serves as useful groundwork for
further elaboration and refinement of the theory related the moisture behaviour
and its influence on the transient temperatures in the exhaust system.
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Development of high temperature SiC based field effect sensors for internal combustion engine exhaust gas monitoringWingbrant, Helena January 2003 (has links)
While the car fleet becomes increasingly larger it is important to lower the amounts of pollutants from each individual diesel or gasoline engine to almost zero levels. The pollutants from these engines predominantly originate from high NOx emissions and particulates, in the case when diesel is utilized, and emissions at cold start from gasoline engines. One way of treating the high NOx levels is to introduce ammonia in the diesel exhausts and let it react with the NOx to form nitrogen gas and water, which is called SCR (Selective Catalytic Reduction). However, in order to make this system reduce NOx efficiently enough for meeting future legislations, closed loop control is required. To realize this type of system an NOx or ammonia sensor is needed. The cold start emissions from gasoline vehicles are primarily due to a high light-off time for the catalytic converter. Another reason is the inability to quickly heat the sensor used for controlling the air-to-fuel ratio in the exhausts, also called the lambda value, which is required to be in a particular range for the catalytic converter to work properly. This problem may be solved utilizing another, more robust sensor for this purpose. This thesis presents the efforts made to test the SiC-based field effect transistor (SiC-FET) sensor technology both as an ammonia sensor for SCR systems and as a cold start lambda sensor. The SiC-FET sensor has been shown to be highly sensitive to ammonia both in laboratory and engine measurements. As a lambda sensor it has proven to be both sensitive and selective, and its properties have been studied in lambda stairs both in engine exhausts and in the laboratory. The influence of metal gate restructuring on the linearity of the sensor has also been investigated. The speed of response for both sensor types has been found to be fast enough for closed loop control in each application. / <p>On the day of the public defence of the doctoral thesis, the status of article III was: in press. Report code: LiU-Tek-Lic-2003:50.</p>
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