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Technical Paper

Automobile Exhaust Emmision Control- A review

2019-11-21
2019-28-2382
Since the 20th century increase in the number of cars in the major cities is been a point of concern because of the toxic gasses being emitted from the engine of an automobile. These gasses are polluting the atmosphere and degrading the air to breathe. The main gasses responsible for the degradation of air quality are carbon monoxide, hydrocarbon and oxides of nitrogen. There is a necessity to find ways to reduce the pollution emitted into the atmosphere from the automobile. The source of emission is either evaporation from fuel tank or carburetor which is easy to be dealt with or harmful gasses due to improper combustion which is a concern for the environment. The two ways to reduce these emissions are, modification in the engine to minimize the production of harmful gases and to treat the harmful gasses emitted from the engine before blowing it into the atmosphere from the exhaust. Catalysts help to break harmful gasses into smaller compounds that are environment-friendly.
Technical Paper

Thermal Challenges in Automotive Exhaust System through Heat Shield Insulation

2019-11-21
2019-28-2539
While advanced automotive system assemblies contribute greater value to automotive safety, reliability, emission/noise performance and comfort, they are also generating higher temperatures that can reduce the functionality and reliability of thesystem over time. Thermal management and insulation are extremely important and highly demanding in BSVI, RDE and Non-IC engine operating vehicles. Passenger vehicle and Commercial vehicle exhaust systems are facing multiple challenges such as packaging constraints, weight reduction andthermalmanagement requirements.Frugal engineering is mandatory to develop heat shield in the exhaust system with minimum heat loss. The focus of the paper is to design, develop and validate heat shield products with different variables such as design gap, insulation material, sheet metal thickness and manufacturing processes. 1D and 3D computational simulations are performed with different gaps from 3 mm to 14 mm are considered.
Technical Paper

Engine Valve Train Dynamic Analysis using 1-D Simulation Approach

2019-11-21
2019-28-2422
In order to reduce engine development timing and cost, a numerical calculation used to evaluate valve train systems. This paper discusses the work done on kinematic and dynamic analysis of Valve Train (VT) system of a diesel engine by using 1-D Ricardo Valdyn software. The goal is to meet optimum intake, exhaust valve timing requirement, maximize valve open area and 20% overspeed requirement. Valve train model is prepared and inputs like mass and stiffness are estimated from actual weighing and finite element approach respectively. Simulation model is used for predicting valve bounce speed, valve displacement, cam-follower contact stress and strain in the rocker arm. Initially, Kinematic analysis is carried out to study the change in valve motion characteristics such as cam contour radius, tappet contact eccentricity etc. Further to this, dynamic analysis is carried out to assess forces and stresses on valve train components.
Technical Paper

Development of Diesel Particulate NOx Reduction DPNR System for Simultaneous Reduction of PM and NOx in Diesel Engines

2019-11-21
2019-28-2554
The Diesel Particulate NOx Reduction (DPNR) system is used for simultaneous reduction of PM and NOx in diesel engine. DPF is used to trap particulate matter in diesel engines. NOx absorber technology removes NOx in a lean (i.e. oxygen rich) exhaust environment for both diesel and gasoline lean-burn GDI engines. The NOx storage and reduction catalyst is uniformly coated on the wall surface and in the fine pores of a highly porous filter substrate. Combination of these two components in the DPNR results in a compact size of the system. The base diesel engine model validated with pressure crank angle diagram and performance parameters such as Indicated mean effective pressure. This base engine’s exhaust emission is given as an input to the DPNR system. The surface reaction is connected to the DPF through chemcon template. The surface reaction is NOx storage and reduction chemical kinetics like Lean NOx Trap. The modelling of DPNR and Base engine is done using GT-SUITE.
Technical Paper

Materials for DPF and its Cleaning Methodologies

2019-11-21
2019-28-2565
Accumulation of ash in the Diesel Particulate Filter (DPF) with engine operating over the time is a major concern for all vehicle manufacturers, with BS VI and BS VII emission norms mandating the use of DPF. Ash deposition leads to increase in pressure drop across the filter and more frequent regeneration pattern, which can lead to sintering. It can hamper the capacity of soot loading, properties of DPF substrate material and can lower catalyst activity in case of Catalysed-DPF. Hence, removal of ash is important by defining the DPF cleaning methods. Primary source of ash is lubricant oil, taking part in the combustion. Lubricant additives like detergents and anti-wear agents are responsible for formation of metallic ash inside the DPF. Secondary source of metallic ash is fuel and engine wear out. The present paper elucidates the preparation of DPF samples including coating and canning of DPF substrates, with proper GBD.
Technical Paper

Modeling for collective effect of Muffler geometric modifications and blended microalgae fuel use on exhaust performance of a four-stroke diesel engine: A Computational Fluid Dynamics Approach

2019-11-21
2019-28-2377
Engine performance significantly depends on the effective exhaust of the combustion gases from the muffler. With stricter BSVI norms more efficient measures has to be adopted to reduce the levels of exhaust emissions from the exhaust to the atmosphere. Muffler along with reducing the engine noise, is intended to control the back pressure as well. Back pressure change has significant effect on muffler temperature distribution which affects the NOx emission from the exhaust. Many research communications have been made to reduce the exhaust emissions like HC, CO and CO2 from the exhaust by using different generation biofuels as alternate fuel, yet they have confronted challenges in controlling the NOx content from exhaust. This work presents the combined effect of Muffler geometry modifications and blended microalgal fuel on exhaust performance with an aim to reduce NOx emission from the exhaust of a four-stroke engine.
Technical Paper

Experimental investigations on CO2 recovery from petrol engine exhaust using adsorption technology

2019-11-21
2019-28-2577
Energy policy reviews state that automobiles contribute 25% of the total Carbon-di-oxide (CO2) emission. The current trend in emission control techniques of automobile exhaust is to reduce CO2 emission. We know that CO2 is a greenhouse gas and it leads to global warming. Conversion of CO2 into carbon and oxygen is a difficult and energy consuming process when compared to the catalytic action of catalytic converters on CO, HC and NOX. The best way to reduce it is to capture it from the source, store it and use it for industry applications. To physically capture the CO2 from the engine exhaust, adsorbents like molecular sieves are utilized. When compared to other methods of CO2 separation, adsorption technique consumes less energy and the sieves can be regenerated, reused and recycled once it is completely saturated. In this research work, zeolite X13 was chosen as a molecular sieve to adsorb CO2 from the exhaust.
Technical Paper

Experimental and Computational Investigation of Particle Filtration Mechanisms in Partially Damaged DPFs

2019-09-09
2019-24-0149
Since September 2018 new threshold limits are applied in the European Union for On-Board Diagnosis (OBD) of particulate mass (PM) leakage. OBD systems are obliged to detect exhaust system malfunctions that account to 2.5 times higher PM emissions compared to the type approval limit. Often the malfunction is located in the Diesel Particulate Filter (DPF), which might suffer substrate crack or melting during harsh regeneration events. In addition, DPF systems have become a tampering target, usually to avoid the high cost of replacement or lower fuel consumption. In this context, understanding the filtration mechanisms in partially damaged DPFs can facilitate the assessment of their environmental effects and the design of exhaust systems with efficient OBD functionality. Two common types of DPF failure are included in this study, namely partial rear plug removal and internal crack development due to uncontrolled regeneration with excessive soot loading.
Technical Paper

Analysis of TWC Operation Characteristics in a Euro6 Gasoline Light Duty Vehicle

2019-09-09
2019-24-0162
A Euro6 gasoline light duty vehicle has been tested at the engine dynamometer and the emissions have been analyzed upstream and downstream the Three-Way-Catalyst (TWC) during the WLTP cycle. Catalyst simulations have been used for assessing the processes inside the catalytic converter using a reaction scheme based on 19 brutto reactions (Direct oxidation and reduction, selective catalytic re-ductions with CO, C3H6 and H2, steam reforming, water-gas shift and bulk Ceria as well as surface Ce-ria reactions). The reactions have been parametrized in order to best approximate the measurements. Based on the reactions taken into account, the real vehicle emissions can be predicted with good accu-racy. The simulations show that the cycle emissions are comprising mainly by the cold start contribution as well as discrete emission break-through events during transients.
Technical Paper

Chemical and Physical Characterization of Organic Particulate Matter from Last Generation Exhaust Aftertreatment System of Medium Duty Diesel Engine

2019-09-09
2019-24-0053
Particulate Matter from Euro 6 Medium Duty diesel engine was analyzed from engine-out, downstream of particulate filter (DPF), and up to the exit of a selective catalytic reactor (SCR) to characterize its chemical and physical nature. Particular attention was devoted to the analysis of particles down to 23 nm. An array of chemical, physical and spectroscopic techniques (Gas chromatography coupled with mass spectrometry (GC-MS), mobility analyzer, UV-visible absorption and fluorescence spectroscopy) was applied for characterizing the organic particulate matter (PM, constituted of polycyclic aromatic hydrocarbons (PAH), heavy aromatic compounds, soot) in the exhaust. The engine was operated at “full-load” (100% of the total power, representing the best performance of the engine operation) condition, and at different engine speeds. Results showed that the DPF efficiency was greater than 96% in the reduction of the sub 23 nm particles across the speeds range.
Technical Paper

Experimental Investigations on Engine-Out Emissions Sensitivity to Fuel Injection Pressure of a High-Performance DISI Single Cylinder Engine

2019-09-09
2019-24-0169
In recent times complying with increasingly stringent emission regulations has become ever more challenging. While an efficient after-treatment system that includes gasoline particulate filter enables compliance with legislation requirements, lowering engine-out emissions by improving combustion system has to be considered as a crucial advantage not only in regard to pollutants emission control, but also performance. In this respect, high-performance enabling contents such as relatively large displacement, flow-capacity oriented intake ports and a limited stroke-to-bore ratio have significant drawbacks on the charge motion quality and as direct consequence on mixture formation and homogeneity.
Technical Paper

Hybrid Powertrain Calibration Techniques

2019-09-09
2019-24-0196
Meeting the particle (PN) emissions limits in dynamic vehicle test sequences needs specific attention on each power variation event occurring in the internal combustion engine (ICE). Such transients arise from engine start onwards along the entire test drive. In hybrid systems, there is one further source for transient ICE response: each power shift between E-motor (EM) and ICE introduces gas flow variations with subsequent temperature response in the ICE and in the engine aftertreatment system (EAS). This bears consequences for engine out emissions as well as for the EAS efficiency and even for the durability of a catalytic converter. As system calibration engineers must decide on numerous actuator parameters, their decisions, finally, are crucial for meeting legislative limits under the boundary conditions given by the ICE’s hybrid and drive environment.
Technical Paper

Analysis of the Emission Conversion Performance of Gasoline Particulate Filters Over Lifetime

2019-09-09
2019-24-0156
Gasoline particulate filters (GPF) recently entered the market, and are already regarded a state-of-the-art solution for gasoline exhaust aftertreatment systems to enable EU6d-TEMP fulfilment and beyond. Due to their rapid market introduction, extensive field experience with GPFs is not yet available. Especially for four-way catalytic converters, the prognosis of the emission conversion performance over lifetime poses an ambitious challenge, which significantly influences future catalyst diagnosis calibrations. In the first part of the paper, experimental GPF ash loading results are presented. Since most of the ash accumulated in the filter results from the combustion of lubricating oil additives, a burner test bench with a purpose-designed oil injection system was chosen for the investigations. The analysis of the backpressure results show that, contrary to high soot loadings, the ash load has a relatively low impact on engine performance and fuel consumption.
Technical Paper

In-Cylinder Flow Measurements in a Transparent Spark Ignition Engine

2019-09-09
2019-24-0099
Flame development, combustion efficiency and emissions of a gasoline direct injection engine are strongly related with mixture preparation. Consequently, it is important to investigate the flow field and turbulence quantities at the parts of the thermodynamic cycle in which mixture preparation occurs. Flow field measurements were obtained by using 2D digital Particle Image Velocimetry technique in a 475cc optical single – cylinder GDI spark ignition engine. The results include phase averaged velocity fields at 1000 and 1500 RPM with 100% and 25% throttle position. These sets of measurements were conducted for cold flow conditions at three different planes including the tumble plane and the swirl plane. The flow was recorded at various crank angles between -340° and -20° before the combustion top dead center (BTDC) with an increment of 40°. The spatial averaged TKE (Turbulent Kinetic Energy) was calculated along with the TR (Tumble Ratio).
Technical Paper

Experimental and Numerical Analysis of Latest Generation Diesel Aftertreatment Systems

2019-09-09
2019-24-0142
A comprehensive experimental and numerical analysis of two state-of-the-art diesel AfterTreatment Systems (ATS) for automotive applications is presented in this work. Both systems, designed to fulfill Euro 6 emissions regulations standards, consist of a closed-coupled Diesel Oxidation Catalyst (DOC) followed by a Selective Catalytic Reduction (SCR) catalyst coated on a Diesel Particulate Filter (DPF), also known as SCR on Filter (SCRoF). While the two systems feature the same Urea Water Solution (UWS) injector, major differences could be observed in the UWS mixing device, which is placed upstream of the SCRoF, whose design represents a crucial challenge due to the severe flow uniformity and compact packaging requirements.
Technical Paper

Diesel Vehicle with Ultra-low NOx Emissions on the Road

2019-09-09
2019-24-0145
The paper discusses the technical approach to meet Euro 6d Real-Driving Emissions (RDE) requirements and beyond, with a particular focus on reducing diesel NOx emissions in urban driving situations. Novel technology aspects of the diesel powertrain are an RDE-optimized catalyst system layout to improve both low- and high-load DeNOx performance and a 48V P0-hybrid system. A key element of the powertrain concept is the advanced model based DeNOx control strategy. The optimized exhaust aftertreatment layout combines lean NOx Trap (LNT) and Selective Catalytic Reduction (SCR) technologies. For maximum low load DeNOx performance, the close-coupled SCR, consisting of an additional slice upstream of an SCR coated on filter, is assisted by an LNT. High load conditions are covered by a 2-stage SCR system with twin AdBlue® dosing. The P0 48V electric motor supports the NOx control in addition to ensuring good driving performance and fuel efficiency.
Technical Paper

Heat Transfer Characterization of Catalytic Converter Substrates During Warm-Up

2019-09-09
2019-24-0163
The transient heat transfer behavior of a real size automotive catalytic reactor has been simulated with OpenFOAM in 1D. The model takes into consideration the gas-solid convective heat transfer, axial wall conduction and heat capacity effects in the solid phase, but also the chemical reactions of CO and C3H6 oxidations, based on simplified Arrhenius and Langmuir-Hinshelwood approaches. The associated parameters have been chosen based on the tuning of experimental data. The impact of different initial catalytic converter temperatures, inlet flow temperatures and inlet flow rates have been quantified, even in terms of overall cumulative emissions. . A dimensional analysis is proposed and dimensionless temperature difference and space-time coordinate are defined. Using this suitably modified coordinates, for the case of negligible axial solid conduction, computed solid temperature at the reactor outlet lay on the typical S-curve.
Technical Paper

Pressure Drop of Particulate Filters and Correlation with the Deposited Soot for Heavy-Duty Engines

2019-09-09
2019-24-0151
Particulate filters are a widely used emission control device on heavy-duty diesel engines. The accumulation of particulate matter, mostly consisting of soot, inside the filter results in increased filter pressure-drop (backpressure). This increased backpressure has been used by the on-board control systems as trigger for regeneration procedures, which aim to actively oxidize the accumulated soot. However, it is known that passive soot oxidation during normal operation affects the correlation between backpressure and the deposited soot mass in filter. Therefore, the backpressure alone cannot be a reliable trigger for regeneration. In this work we highlight operating conditions with very poor correlation between backpressure and accumulated soot mass in filter and evaluate the possible root causes. Experiments with several heavy-duty diesel engines and particulate filters were conducted on engine test bench.
Technical Paper

Optimization of the Exhaust Aftertreatment System of a Heavy Duty Engine by means of Variable Valve Timing

2019-09-09
2019-24-0143
In view of the current political debate, it can be assumed that the nitrogen oxide limits for commercial vehicles will be further reduced. This is also demonstrated by the currently voluntary certification of the CARB Optional Low NOX legislation, which requires nitrogen oxide emissions of 0.027 g / kWh. This corresponds to a reduction of 93% compared to the current EU VI standard. Therefore, the optimization of EAT systems represents an essential research focus for future commercial vehicle applications. One way to optimize the EAT system may be the usage of variable valve actuation. Existing investigations show an exhaust gas temperature increase with Miller timing, but the authors conclude that it cannot accelerate the heating process. With regard to the effects on the exhaust aftertreatment system and the resulting tailpipe emissions, only improved HC and CO oxidation could be identified so far.
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