EGR Cooler Fouling Reduction: A New Method for Assessment in Early Engine Development Phase

<div class="htmlview paragraph">The analysis reported on in this paper examines environmental, energy and economic benefits for specific, though different, proposed state wide high speed rail (HSR) systems combined with a regional maglev proposal under review in Florida. One of the HSR proposals and the maglev system are projected to be fully permitted within the next eighteen months and operational by the 1994-96 period.</div> <div class="htmlview paragraph">The specifics of each applicants proposals are integrated into a complex computer model which reflect different; 1) technologies and speeds, 2) energy demands and other resource needs, 3) system service level characteristics, 4) ridership levels, 5) modal splits combined with 6) other system differences.</div> <div class="htmlview paragraph">This computer model then integrates the unique a) fuel consumption and b) emission levels of the actual electrical generation grid supplying the HSR and maglev systems in central and south Florida.</div> <div class="htmlview paragraph">Finally, the model quantitatively combines this data with equivalent emissions, energy and other system information on auto and airplane transportation modes. This data and pertinent user characteristics enable the model to estimate precise environmental, energy and economic benefits (expressed in 1990 dollars) for each unique HSR and maglev transportation system for the year 1999 alone.</div> <div class="htmlview paragraph">The results of this Florida specific analysis conclude that implementation of a HSR proposal and the maglev system will annually result in:</div> <section id="s_1" class="section"> <h2 class="title">Economic and Energy Benefits</h2> <div class="htmlview paragraph">- Time savings valued to $85 million.</div> <div class="htmlview paragraph">Automobile wear and maintenance savings valued to $37.4 million.</div> <div class="htmlview paragraph">Property and injury loss savings valued to $8 million.</div> <div class="htmlview paragraph">Reduction in annual transportation energy consumption of between 1.13 to 1.69 trillion Btus.</div> <div class="htmlview paragraph">Reduced dependence of $28.4 million on fossil fuel to power our transportation systems.</div> <div class="htmlview paragraph">Reduction of $23.5 million in imported oil thereby strengthening this nation's domestic economy by A) reducing negative balance of payments, B) increasing reliance on domestic sources of energy, and C) increasing domestic security.</div> <div class="htmlview paragraph">Reduce the annual economic damages (externalities) from transportation air pollution emissions.</div> <div class="htmlview paragraph">Additionally HSR/maglev systems will result in</div> <div class="htmlview paragraph"> <ul class="list disc"> <li class="list-item"> <div class="htmlview paragraph">Savings in new highway construction costs exceeding $1 billion.</div> </li> <li class="list-item"> <div class="htmlview paragraph">Up to 217,979 man year direct and indirect construction employment.</div> <div class="htmlview paragraph">Up to $20 billion in indirect construction income.</div> </li> <li class="list-item"> <div class="htmlview paragraph">As much as 9,908 annual permanent operations jobs created both direct and indirect.</div> <div class="htmlview paragraph">Over $300 million annually in direct and indirect operation employment income.</div> </li> <li class="list-item"> <div class="htmlview paragraph">- Enhanced transportation productivity by a factor of three over current modes.</div> </li> </ul> </div> </section> <section id="s_2" class="section"> <h2 class="title">Environmental Emissions Benefits and Costs</h2> <div class="htmlview paragraph">- Annual reductions of between 555 to 633 tons/year of Volatile Organic Carbons (VOC) emissions.</div> <div class="htmlview paragraph">Annual reductions of between 3,035 to 4,746 tons (2753 to 4305 mtons) year of Carbon Monoxide (CO).</div> <div class="htmlview paragraph">Annual reductions of between 53,890 to 54,467 tons (48878 to 49402 mtons) year of Carbon Dioxide (CO<sub>2</sub>).</div> <div class="htmlview paragraph">Annual reductions of between 877 to 1,184 tons (795 to 1074 mtons) year of Nitrogen Oxides (NOx).</div> <div class="htmlview paragraph">Annual reductions of between 57 to 84 tons (52 to 76 mtons) year of Total Suspended Particulate (TSP) matter.</div> <div class="htmlview paragraph">Annual reductions of between 49 to 78 tons (44 to 71 mtons) year of tire wear particulate matter.</div> <div class="htmlview paragraph">Annual increases of between 132 to 173 tons (120 to 157 mtons) year of Sulfur Oxides (SOx).</div> <div class="htmlview paragraph">Total non-CO<sub>2</sub> auto and airplane emissions exceed HSR and maglev emissions by a factor of 14.</div> <div class="htmlview paragraph">Total automobile and airplane emissions (including CO<sub>2</sub>) exceed HSR and maglev emissions by 200%.</div> <div class="htmlview paragraph">With proper mitigation measures, environmentally related noise impacts can be resolved.</div> </section> <section id="s_3" class="section"> <h2 class="title">Growth in all Benefits/Costs</h2> <div class="htmlview paragraph">All of these HSR/maglev social benefits will rise by a factor of 1.75 of any percentage improvements in trip times while ridership revenues to system owners could rise by a factor of 2.7.</div> </section>

<div class="section abstract"><div class="htmlview paragraph">Growing concerns about the emissions of internal combustion engines have forced the adoption of aftertreatment devices to reduce the adverse impact of diesel engines on health and environment.</div><div class="htmlview paragraph">Diesel particulate filters are considered as an effective means to reduce the particle emissions and comply with the regulations. Research activity in this field focuses on filter configuration, materials and aging, on understanding the variation of soot layer properties during time, on defining of the optimal strategy of DPF management for on-board control applications.</div><div class="htmlview paragraph">A model was implemented in order to simulate the filtration and regeneration processes of a wall-flow particulate filter, taking into account the emission characteristic of the engine, whose architecture and operating conditions deeply affect the size distribution of soot particles. The model is based on a lumped parameter approach able to be used for on-board monitoring and control, in order to provide knowledge of DPF status versus time.</div><div class="htmlview paragraph">The filtration model is based on the ‘unit collector’ and fluid dynamic approaches to predict trapped mass and filter backpressure evolution during time. The model accounts for the size distribution of soot particles in the engine exhaust and for its impact on the DPF properties during loading process. Regeneration model is based on a O<sub>2</sub> non-catalytic oxidation approach of the trapped soot.</div><div class="htmlview paragraph">The model was applied to simulate the loading/regeneration processes of a wall-flow DPF under real engine operation condition. Experimental tests were carried out and measurements were used to validate the proposed model.</div></div>

<div class="htmlview paragraph">Regulated and non-regulated emissions from five current European diesel passenger cars and one light-duty diesel truck were measured to assess the environmental impact of diesel vehicles and to help determine the emission characteristics of the two types of combustion systems: indirect injection (IDI) and high speed direct injection (HSDI). The vehicle emissions were measured using the European Motor Vehicle Emissions Group (MVEG) cycle and the U.S. Federal (FTP 75) test procedures. Measured emissions included HC, CO, NO<sub>x</sub> and particulate mass (PM), C<sub>1</sub> to C<sub>12</sub> hydrocarbon species (here called light hydrocarbon or LHC), aldehydes, particulate composition and particle size distribution. The particulate composition measurements included soluble organic fraction (SOF), its oil and fuel sub-fractions, and the sulfate fraction. All passenger cars and the light-duty commercial vehicle tested complied with the current European Emissions Directive 91/441/EEC. Two passenger cars achieved the EEC Stage 2 levels, and one nearly met the 1994 Tier I U.S. Federal standards. The LHC accounted for between 35 to 78% of the total HC measured by the heated FID analyzer. Fuel and oil comprised between 12 and 30% of the PM emissions. The non-methane organic gases (NMOG) emissions and the LHC ozone reactivity from diesel cars were both about 50% less than those from gasoline cars. Of the non-regulated emissions, formaldehyde was generally below 0.009 g/km, and benzene emissions were below 0.0035 mg/km. The results were compared with European gasoline vehicles and the Current Gasoline Vehicle fleet of the U.S. Air Quality Improvement Program (AQIRP), and an assessment was made of the relative environmental impacts of gasoline and diesel vehicles.</div> <div class="htmlview paragraph">Over the last 20 years, there has been a substantial effort to lower the exhaust emissions from both diesel and gasoline passenger vehicles. Over the same period, the percentage of diesel passenger vehicles purchased in Europe has been increasing steadily(<span class="xref">1</span>)<span class="xref">*</span>. Lower operating(<span class="xref">2</span>) and maintenance costs, and better durability with equivalent drive performance appear mainly responsible for the increased diesel sales. However, even though both diesel and gasoline vehicles meet the current emission standards, questions have arisen about their relative impact on the environment(<span class="xref">3</span>). In addition, with future requirements for lower emissions, these questions will undoubtedly continue.</div> <div class="htmlview paragraph">The relative environmental impact of diesel and gasoline vehicles is still uncertain because there are relatively few published data on the emissions of current diesel vehicles and because the environmental impacts of the expected emissions are not clearly understood. Data on the regulated emissions for diesel passenger vehicles sold in Europe are available from the German Government:(<span class="xref">4</span>) starting in 1991. There are also published reports on regulated emissions from late 1980 and early 1990 diesel cars in the literature(<span class="xref">5</span>,<span class="xref">6</span>,<span class="xref">7</span>). Still there are few reports on the non-regulated emissions from current diesel vehicles(<span class="xref">8</span>,<span class="xref">9</span>,<span class="xref">10</span>).</div> <div class="htmlview paragraph">On the other hand, there are substantial published data on the regulated emissions of current gasoline vehicles(<span class="xref">11</span>). In addition, there are substantial data on the non-regulated emissions of gasoline cars, especially from the U.S. Air Quality Improvement Research Program (AQIRP)(<span class="xref">12</span>). The AQIRP emissions data included measurements of over 150 individual hydrocarbon and aldehydic compounds which allow estimates of the amount of urban ozone formed from the exhaust and of the atmospheric toxic compound levels. Diesel vehicles were not included in AQIRP.</div> <div class="htmlview paragraph">This paper reports on detail regulated and non-regulated emissions measurements for six 1992/93 model year diesel vehicles, including two Ford and four competitor vehicles. The emissions were measured on both the 1993 European MVEG cycle and the U. S. Federal test procedure. The U. S. AQIRP analytical methods were used for hydrocarbon and aldehydic speciation. The report discusses the regulated emissions from the six diesel vehicles compared to emissions standards, their contribution to urban ozone formation, toxic levels and global warming. It also compares the exhaust emissions of current diesel and gasoline vehicles to help clarify their relative environmental impact.</div>

<div class="htmlview paragraph">As a first attempt to assess the scope for reducing the emissions from gasoline fuelled vehicles in the European market via fuel changes, an experimental scouting programme has been conducted to examine the effects of fuel composition and properties on both regulated emissions and detailed exhaust gas composition. This 4 fuels/4 vehicles programme involved exhaust emission tests on a chassis dynamometer, and was carried out mainly on non-catalyst vehicles, using two commercial gasolines and two (“reformulated”) test gasolines representing “intermediate” and “extreme” changes of the base gasoline design. The fuel characterization includes analysis by hydrocarbon type and carbon number; the exhaust analysis comprises both regulated emissions and hydrocarbon speciation measurements.</div> <div class="htmlview paragraph">In the case of regulated emissions, the fuel effects are, as expected, relatively small in comparison with the effect of installing exhaust catalysts. Nevertheless, significant emission benefits are achieved via the fuel changes relative to one of the commercial gasolines. Interestingly, however, relatively modest changes prove to be sufficient to produce these benefits, and further extreme reformulation does not promote additional emissions reductions. Moreover, the second commercial gasoline gives essentially the same reductions in total hydrocarbon and carbon monoxide (but not nitrogen oxides) emissions as the two “reformulated” fuels.</div> <div class="htmlview paragraph">Exhaust gas hydrocarbon speciation profiles for a given fuel are very similar for different cars and different (i.e cold and hot ) parts of the driving cycle. The detailed hydrocarbon composition of the exhaust gas is dominated by the gasoline composition, with the exception of the exhaust olefins which are as dependent on the paraffins as on the olefin content of the fuel.</div> <div class="htmlview paragraph">A much larger follow-up programme is now underway in which the fuel effects on emissions are being investigated systematically for both catalyst and non-catalyst cars via independent variation of individual fuel parameters.</div>

<div class="section abstract"><div class="htmlview paragraph">Cooled EGR provides benefits in better fuel economy and lower emissions by reducing knocking tendency and decreasing peak cylinder temperature in gasoline engines. However, GDI engines have high particle emissions due to limited mixing of fuel and air, and these particle emissions can be a major source of EGR cooler fouling. In order to improve our knowledge of GDI engine EGR cooler fouling, the effects of tube geometry and coolant temperature on EGR cooler performance and degradation were studied using a four cylinder 2.0L turbocharged GDI engine. In addition, deposit microstructure was analyzed to explore the nature of deposits formed under GDI engine operation. The results of this study showed that a dented tube geometry was more effective in cooling the exhaust gas than a smooth tube due to its large surface area and turbulent fluid motion. However, more deposits were accumulated and higher effectiveness loss was observed in the dented tube. Furthermore, the dented tube had a larger pressure drop across the EGR cooler. Microstructure analysis revealed that the deposit mass and thickness decrease with axial distance from the tube inlet due to variation of thermophoresis along the tube.</div></div>

<div class="htmlview paragraph">The effects of engine operating conditions on the octane requirement and the resulting knock-limited output were studied on a single cylinder engine using production cylinder heads. A 4-valve cylinder head with port deactivation was used to study the effect of fuel octane, inlet air temperature, coolant temperature, air/fuel ratio, compression ratio and exhaust back pressure. The effect of the thermal environment was studied in more detail using separate cooling systems for the cylinder head and engine block on a 2-valve cylinder head.</div> <div class="htmlview paragraph">The results of this study compared closely with results found in the literature even though the engine and/or operating conditions were quite different in many cases. Guidelines on the effect of various parameters on the octane requirement of an engine can be summarized as follows:</div> <div class="htmlview paragraph"> <ul class="list disc"> <li class="list-item"><div class="htmlview paragraph">Spark Advance: 1 ON/1° SA</div></li> <li class="list-item"><div class="htmlview paragraph">Intake Air Temperature: 1 ON/7 K</div></li> <li class="list-item"><div class="htmlview paragraph">Air/Fuel Ratio: peaks at 5% rich of stoichiometric, decreases by around 2 ON / air/fule ratio around peak</div></li> <li class="list-item"><div class="htmlview paragraph">Intake Pressure: 3-4 ON/10 kPa</div></li> <li class="list-item"><div class="htmlview paragraph">Compression Ratio: 5 ON/CR</div></li> <li class="list-item"><div class="htmlview paragraph">Exhaust Back Pressure: 1 ON/30 kPa</div></li> <li class="list-item"><div class="htmlview paragraph">Coolant Temperature: 1 ON/10 K (Similar effect of head and block temperature., Larger effect at low speed.)</div></li> </ul> </div>

<div class="section abstract"><div class="htmlview paragraph">Gasoline direct injection (GDI) engines usually emit higher levels of particulates in warm-up conditions of a driving cycle. Thus, sources of soot formation in these conditions were investigated by measuring particulate numbers (PN) emitted from a single-cylinder GDI engine and their sizes. The combustion was also visualized using an endoscope connected to a high-speed camera. Engine coolant and oil temperatures were varied between 15 and 90<sup>o</sup>C to mimic warm-up conditions. In addition, effects of delaying the start of ignition (SOI) on the emissions in these conditions were examined.</div><div class="htmlview paragraph">Coolant and oil temperatures were varied individually to identify which factor has most effect on PN emissions. While coolant temperature strongly influenced PN with cold oil, the oil temperature insignificantly affected PN at low coolant temperature. These findings indicate that PN emissions are heavily dependent on the engine block’s temperature, which is dominated by the coolant.</div><div class="htmlview paragraph">SOI plays a significant role in PN formation because it influences the wall film thickness on the piston top. In the experimental warm-up conditions, injecting fuel at a later SOI was found to decrease PN emissions. Visualization showed no occurrence of diffusion flames at late SOI timings due to the associated reduction in interaction between liquid fuel and the piston.</div><div class="htmlview paragraph">The integrated luminescence from combustion images was found to correlate closely with PN emission measurements. Thus, higher integrated luminescence, indicating higher soot formation due to pool fires on the piston top, was associated with higher PN levels. When coolant and oil temperatures were both varied, PN emissions were found to decline dramatically with increasing temperatures. At lower temperatures, diffusion combustion occurred on the piston due to persistence of a non-vaporized fuel film. At 15<sup>o</sup>C coolant and oil temperature, this phenomenon was strong, but it gradually declined as the temperature increased. When the temperature reached 60<sup>o</sup>C, diffusion flames started to disappear, resulting in a dramatic decrease in PN.</div></div>

<div class="htmlview paragraph">A chemical and physical characterization of particulate emitted in undiluted exhaust of single cylinder direct injection (D.I.) diesel engine was made by an optical technique.</div> <div class="htmlview paragraph">On-line scattering and extinction measurements in the spectral range from 200 to 500nm were carried out in the exhaust ofthe engine operating under steady-state conditions. These measurements provided a useful tool for the comprehension of chemical and physical structure of the particulate. They allowed the evaluation in real time of the size, the concentration and also the optical properties. Preliminary results of size and mass concentration of particulate are presented.</div> <div class="htmlview paragraph">A good agreement was observed comparing the results with those obtained by gravimetric measurements, TEM and X-ray diffraction.</div> <div class="htmlview paragraph"><b>HIGH EFFICENCY OF DIESEL ENGINES</b> and their ability to burn heavy fuels make them ofgreat interest in the transportation field. On the other hand, present exhaust emission levels produced by this type ofengine will not satisfy stringent international regulations on environ- menta protection.</div> <div class="htmlview paragraph">The studies of the chemical and physical structure of diesel particulate in the exhaust of the engine help manufacturers both to optimize the efficiency of the combustion process and give useful information to designers of after-treatment devices.</div> <div class="htmlview paragraph">Historically, most studies on the particulate in the engine exhaust were carried out by electron microscopy and chemical analysis [<span class="xref">1</span>,<span class="xref">2</span>]<span class="xref">*</span>. These conventional techniques are time consuming, not real time, and not useful in transient operating conditions. Because the composition of the particulate materia depends on the collection system the data can be influenced by sampling procedures.</div> <div class="htmlview paragraph">Size distribution measurementtechniques of particulate based on electrical mobility, diffusion and inertial separation were proposed by Dolanetal.[<span class="xref">3</span>]. These techniques are real time but intrusive and can change the size distribution through collisions between particles.</div> <div class="htmlview paragraph">The recent advances in non-intrusive optical diagnostic techniques have made it possible to study on-line the evolution of particulate emitted in the exhaust with good temporal and spatial resolution.</div> <div class="htmlview paragraph">In the last decade, the optical measurements carried out in the exhaust, were made by nephetometry, transmissiometryor opacimetry, generally at a single wavelength in the visible range or in the infrared by photoacoustic and absorption measurements, These measurements are used to determine both the mass of particulate and the amount of dry soot and SOF [<span class="xref">4</span>,<span class="xref">5</span>,<span class="xref">6</span>,<span class="xref">7</span>.]</div> <div class="htmlview paragraph">In particular, simultaneous light scattering and extinction measurements at a single wavelength in the visible have provided a fast method to determine the dimension and concentration of soot particles i n flame [<span class="xref">8</span>].</div> <div class="htmlview paragraph">The purpose of the present study is to demonstrate the feasibility and flexibility of a new optical technique applied in the undiluted exhaustof a D.I. diesel engine. The technique consists of the use of simultaneous spectral measurements of scattering and extinction coefficients from the near ultraviolet to visible. These measurements allow the on-line simultaneous evaluation of the size, concentration and particulate mass as well as estimating the optical properties of the particulate. In particular, optical measurements in the near ultraviolet region are particularly promising because both graphite and large aro- maticmolecules exhibit absorption bands between 200 and 350nm [<span class="xref">9</span>,<span class="xref">10</span>].</div>

<div class="htmlview paragraph">In the past decade, SCR deNOx technology with urea injection has grown to maturity. European OEMs will apply SCR deNOx to meet future heavy-duty emissions legislation starting with EURO-4 (2005/2006). Numerous research programs in Europe and the US have shown a variety of system layouts and control strategies. The main differences are formed by:</div> <div class="htmlview paragraph"> <ul class="list disc"> <li class="list-item"><div class="htmlview paragraph">the engine-out NO<sub>x</sub> calibration</div> </li> <li class="list-item"><div class="htmlview paragraph">the application of an NO to NO<sub>2</sub> catalyst</div> </li> <li class="list-item"><div class="htmlview paragraph">open-loop or closed-loop urea dosage control.</div> </li> </ul> </div> <div class="htmlview paragraph">This paper gives an overview of possible SCR system configurations that are required for different stages of future emission legislation.</div> <div class="htmlview paragraph">Engine-out NO<sub>x</sub> emission is strongly influenced by ambient conditions. Projections in this study show that a combination of cold climate and a wintergrade fuel is the most severe: it may lead to 30% lower engine-out NO<sub>x</sub> emission with respect to laboratory conditions. The varying engine-out NO<sub>x</sub> emission requires a safety margin in the case of an open-loop controlled system in order to avoid excessive NH<sub>3</sub> slip.</div> <div class="htmlview paragraph">Calculations in this paper show that Euro 4 limits can be met with open-loop controlled urea dosage; an NO to NO<sub>2</sub> catalyst is even not required. For other future emission legislation (Euro 5, US 2007 and US 2010), it becomes difficult to safely achieve the limits with open-loop control. US 2007 and 2010 legislation require an NO to NO<sub>2</sub> catalyst because of the low average load and consequently low exhaust gas temperatures. Engines that are developed to meet US 2010 legislation need special measures to increase the exhaust gas temperature and to reduce engine-out NO<sub>x</sub> below 2 g/kWh.</div> <div class="htmlview paragraph">In all cases, optimal hydrolysis and mixing conditions are of major importance. High speed photography and droplet size measurements are presented as methods for characterizing and modeling aqueous urea spray patterns. The information from these measurements is used as input parameters for simulation tools. These consist of a 2D/3D CFD program for urea mixing analysis and a 1D SCR system model for development of dosage control and optimization of catalyst dimension.</div> <div class="htmlview paragraph">Finally, simulations with the SCR system model are compared with measurements on the engine test bench.</div>

<div class="htmlview paragraph">This paper presents the numerical simulation method to predict the deactivation process of three-way catalytic converters.</div> <div class="htmlview paragraph">Three-way catalytic converter's deactivation typically results from thermal and chemical mechanisms. The major factor of thermal deactivation is the sintering of noble metal particles, which is known to depend on the ageing temperature and the oxygen concentration in the exhaust gas. The chemical deactivation is mainly caused by the poisoning, which has two effects on the catalyst deactivation. One effect is the loss of the catalyst activity, which is expressed by reduced frequency factors of reaction rates. Another effect is the suppression of the noble metal sintering. Poison deposits prevent the noble metal particles from moving in the washcoat, assisted by the reduced thermal loading of reaction heats, which is caused by the loss of the catalyst activity. Modeling these deactivation factors, we propose the rate expression of noble metal sintering.</div> <div class="htmlview paragraph">The changing process of noble metal particle size and catalyst activity distributions with mileage is simulated by the procedure to predict the deactivation process. This procedure adopts above sintering rate expression, and the details are presented in this paper.</div> <div class="htmlview paragraph">Based on simulated results of the deactivated state inside the bench aged catalyst, which are noble metal particle size and catalyst activity distributions, thermal responses and light-off behaviors during warm-up tests are predicted. Predicted results show good agreement with the measured results.</div> <div class="htmlview paragraph">Moreover, transient conversion behaviors of the bench aged catalyst during LA#4 mode test are predicted. Predicted results lead to the conclusion that the numerical simulation method presented enables the prediction of the relative values of cumulated emissions of aged catalysts with sufficient accuracy.</div>

<div class="section abstract"><div class="htmlview paragraph">The success of improved fuel economy is the proper integration of thermal management components which are appropriately performed to reduce friction and wasted energy. The thermal management systems of vehicle are able to balance the multiple needs such as heating, cooling, or appropriate operation within specified temperature ranges of propulsion systems. Since the propulsion systems of vehicle have changed from a single energy source based on conventional internal combustion engine to hybrid system including more electrical system such as full type of hybrid electric vehicle or plug-in hybrid electric vehicles, a new transition associated with vehicle thermal management arises. More efficient thermal management systems are required to improve the fuel economy in the hybrid electric vehicles because of the driving of electric traction motor and the increase of engine off time. The decrease of engine operation time may not sustain the proper temperature ranges of engine and gearbox. As an engine starts at low ambient temperature, heat from the wasted heat of exhausted gas can be supplied not only to cabin heater, but also to engine and gearbox at initial warm-up.</div><div class="htmlview paragraph">To practically apply recent thermal management technologies in commercial use, improved performance for the low energy density per cost in a viable vehicle package is necessary in general. This research describes the one of cost effective thermal management solutions recovering exhaust gas heat exchanging system with coolant and gear box oil simultaneously. The previous type of recovering the exhaust heat is to exchange the heat between the coolant and the exhaust gas to increase the temperature of the engine coolant, thereby reducing the friction and improving the fuel efficiency. However, the reduction in engine friction loss and improvement of fuel economy remains low due to the short period of exchanging heat between exhaust gas and coolant. It is more advantageous to increase the temperature of the engine oil or gear box oil rather than to increase the coolant temperature. Accordingly, the developed exhaust heat recovery device which performs integral heat exchange of the exhaust gas heat of engine increases the temperature of the coolant and the gear box oil, thereby reducing friction loss and improving fuel economy. The experimental result of this system improved 2.5% of fuel economy at UDDS drive cycles.</div></div>

<div class="htmlview paragraph">To examine the effects of exhaust gas recirculation (EGR) on the exhaust emissions and on the cycle-by-cycle variation of combustion process in a methanol engine, the authors have tried to measure the emissions of total hydrocarbon, carbon monoxides, nitric oxides and formaldehyde and to record the cylinder pressure development histories of 1000 cycles duration. Moreover, the standard deviation of peak pressure Pmax, the heat release rate and the averaged pressure history are analyzed.</div> <div class="htmlview paragraph">The results are compared with those of gasoline fueled operation.</div> <div class="htmlview paragraph">The results are summarized as follows:</div> <div class="htmlview paragraph"> <ol class="list nostyle"> <li class="list-item"> <span class="li-label">(1)</span><div class="htmlview paragraph">In the case of a methanol-fueled engine operated under exhaust gas recirculation (EGR), similar to that already carried out in a gasoline-fueled engine, the concentration of NOx, in the exhaust gas can be decreased but those of formaldehyde (HCHO) and unburned methanol are increased.</div> </li> <li class="list-item"> <span class="li-label">(2)</span> <div class="htmlview paragraph">The effect of EGR, such as 20% of it, on Nox reduction is the same as those of hydrous methanol of 50% water content.</div> </li> <li class="list-item"> <span class="li-label">(3)</span> <div class="htmlview paragraph">In the case of EGR applied to an EFI engine, its output and thermal efficiency are decreased within the lean mixture region (λ>1.0) but these recover and the concentration of hydrocarbon is decreased by raising the fuel temperature.</div> </li> <li class="list-item"> <span class="li-label">(4)</span> <div class="htmlview paragraph">When the optimum conditions of the EGR and fuel temperature are selected, it is possible to improve the exhaust gas characteristics concerning NOx, THC, etc., while the decreased in engine output and thermal efficiency is reduced to the minimum.</div> </li> </ol> </div>

<div class="htmlview paragraph">The use of Diesel engines has strongly increased during the last years and now represents 30% of the sales in Europe and up to 50% of the number of cars in circulation for some countries. This success is linked not only to the economical aspect of the use of such vehicles, but also to the recent technological improvements of these engines. The new technical solutions (high pressure direct injection, turbocharging…) have indeed allowed the increase of these engine performances while decreasing their fuel consumption, pollutant emissions and noise level.</div> <div class="htmlview paragraph">From an environmental point of view, Diesel engines are nevertheless penalized by their particulate and NOx emissions. The study and the treatment of the particulate, highly criticized for their potential impact on health, are the subject of numerous works of characterization and developments.</div> <div class="htmlview paragraph">PSA Peugeot-Citroën has recently launched its particulate filter technology on several types of vehicles. In order to evaluate the durability of this technology over a long period of time, a study program has been set-up by ADEME (French environmental agency), IFP Powertrain, PSA Peugeot-Citroën and G7 (a Parisian taxi company). The objective is to study the evolution of several taxis and their after-treatment system performances over 80 000 km mileage in hard urban driving conditions, which corresponds to the recommended mileage before the first DPF maintenance.</div> <div class="htmlview paragraph">More specifically, the following evaluations are being performed at regular intervals (around 20 000 km):</div> <div class="htmlview paragraph"> <ul class="list disc"> <li class="list-item"><div class="htmlview paragraph">Regulated gaseous pollutant emissions on NEDC cycle (New European Driving Cycle)</div></li> <li class="list-item"><div class="htmlview paragraph">Particulate emissions, by mass measurement on NEDC but also by particle number and size measurement with SMPS (Scanning Mobility Particle Sizer) technique on NEDC and on unconventional steady-state running points.</div></li> <li class="list-item"><div class="htmlview paragraph">Unregulated pollutant emissions (hydrocarbons speciation C<sub>1</sub>-C<sub>13</sub>, oxygenated compounds)</div></li> </ul> </div> <div class="htmlview paragraph">The results obtained until now have not shown any degradation of the particulate filter efficiency. This paper presents the methodology setup and the explanation of the first results obtained. Indeed, a more specific study has shown that most of the aerosols measured with SMPS are composed of liquid fractions, mainly sulfates due to sulfur coming from the fuel, but also from the lubricant. The impact of sulfates stored on the catalyst surface during low temperature running phases and removed during high temperature running phases has also been outlined.</div>

<div class="htmlview paragraph">The 1975 federal CVS test procedure and emission standards have placed a heavy emphasis on minimizing the time required after engine start up to begin converting exhaust emissions. Four major improvements in catalytic HC/CO converters have been made in the past year to reduce catalyst ignition time:</div> <div class="htmlview paragraph"> <ol class="list nostyle"> <li class="list-item"> <span class="li-label">1.</span> <div class="htmlview paragraph">Use of low thermal capacity monolithic catalyst supports.</div> </li> <li class="list-item"> <span class="li-label">2.</span> <div class="htmlview paragraph">Locating converter after thermal reactor and/or closer to the exhaust manifold.</div> </li> <li class="list-item"> <span class="li-label">3.</span> <div class="htmlview paragraph">Development of catalysts with superior stability to long exposure at high temperatures.</div> </li> <li class="list-item"> <span class="li-label">4.</span> <div class="htmlview paragraph">Development of catalysts with improved low temperature activity.</div> </li> </ol> </div> <div class="htmlview paragraph">Small laboratory samples of potential HC/CO oxidation catalysts were screened for activity in a “laboratory simulated cold-start” test with exhaust from a 2-cyl engine. Several improved catalyst candidates were evaluated in a full-size converter “cold-start” test with exhaust from a 351 in<sup>3</sup> engine.</div> <div class="htmlview paragraph">Locating the converters closer to the exhaust manifold results in higher catalyst operating temperatures which require greater stability at high temperatures in the presence of trace contaminants. Stability, when exposed to wide temperature variations and changes from oxidation to reduction environments, has been evaluated in a thermal-cycling test for several improved catalysts. Catalyst stability to long-term exposure has also been evaluated in an engine dynamometer mileage accumulation test operated under simulated road conditions.</div> <div class="htmlview paragraph">Unfortunately, the rapid thermal-chemical response of the improved catalyst, operated closer to the exhaust manifold, increases the occurrences of excessive catalyst temperatures. Mathematical model studies of the effect of the improved catalyst properties on thermal response indicate a need to prevent unexpected high CO or HC concentration peaks in the engine exhaust, or to improve properties of existing catalysts. System changes, such as moving the low temperature catalyst farther from the exhaust manifold, may be required to obtain some protection from catalyst overtemperatures. These changes increase emission levels and require a breakthrough in engine control of raw emissions or improved catalysts.</div>

<div class="htmlview paragraph">The present paper focuses on a system and an appropriate controller concept for an advanced air management system of a turbocharged passenger car diesel engine. The proposed air management system consists of a VTG turbocharger, two separate EGR loops, a non-cooled high-pressure EGR and a cooled low-pressure EGR loop. In the low pressure EGR loop, the exhaust gas leaving the particulate filter is mixed with fresh air just in front of the compressor inlet.</div> <div class="htmlview paragraph">The first step consisted of developing a sensor and actuator concept. Prior to conducting engine tests on this system, GT power simulations were performed. Additionally, a MATLAB/Simulink model was created to design a model-based predictive controller. This model is mainly founded on physical equations, allowing for easy adaptation to various systems.</div> <div class="htmlview paragraph">At the beginning of the engine test stage, stationary measurements were conducted to examine the influence of variations of the EGR rate, boost pressure, fresh air mass, etc. These tests were carried out in an open loop without an integrated controller for the air management system. The results were used to optimize the Simulink simulation model.</div> <div class="htmlview paragraph">As to the controller concept, a model-based predictive approach is presented which uses a simplified simulation model of the complete air path for the prediction.</div> <div class="htmlview paragraph">Furthermore, the system design on the dynamometer and the interaction of the individual steps are described. Simulation results of the new controller type and first results of the controller on the dynamometer are presented, as well.</div> <div class="htmlview paragraph">Due to modifications of the state-of-the-art high-pressure system arising from the integration of a low-pressure EGR line, additional measures need to be taken to protect the components in the inlet air path from harmful impact resulting from corrosion and particulates.</div>