Browse Topic: Catalytic converters
A cold start occurs when the engine is cranked after being off for a long time, enough for its temperature to drop down to the cold ambient levels. Cold start in an engine is a critical phase as it is characterized by elevated emissions. During a cold start, exhaust components such as catalytic converter do not operate in its optimal temperature zone leading to reduced efficiency in emission control. New regulations for engine emissions are becoming stringent for this condition, hence it is important to accurately determine cold start condition in an engine to optimize the emissions control strategy. Accurate engine off time calculation plays a crucial role in cold start detection, emissions control and On-Board Diagnostics (OBD-II) decision making. This engine off time if greater than 6 hours indicates one of the conditions to confirm a cold start. Other conditions such as Ambient temperature and coolant temperature along with the engine off time confirms a cold start. This paper
Spark ignition engines utilize catalytic converters to reform harmful exhaust gas emissions such as carbon monoxide, unburned hydrocarbons, and oxides of nitrogen into less harmful products. Aftertreatment devices require the use of expensive catalytic metals such as platinum, palladium, and rhodium. Meanwhile, tightening automotive emissions regulations globally necessitate the development of high-performance exhaust gas catalysts. So, automotive manufactures must balance maximizing catalyst performance while minimizing production costs. There are thousands of different recipes for catalytic converters, with each having a different effect on the various catalytic chemical reactions which impact the resultant tailpipe gas composition. In the development of catalytic converters, simulation models are often used to reduce the need for physical parts and testing, thus saving significant time and money. However, calibration of these models can be challenging and requires significant time
The model-based design is very much prominent in the vehicle level control system design and state estimation algorithms. It gives the edge to understand and interpret the dynamic systems. Three-way catalytic converter is a thermo-chemical device to convert the toxic oxides into carbon dioxide and water vapor, during this conversion reactions it generates the heat over the catalyst surface. Detailed chemical and thermal model of the catalyst will be able to predict the conversion efficiency, state of stored oxygen (SoX) and oxygen storage capacity (OSC). As the catalyst get aged, the reaction rates of conversion reactions deteriorate, in results the temperature dynamics also varies which wanes the exothermic heat. In this work, a novel perspective is presented to capture the behavior of SoX and health of the catalytic converter using thermal model analysis of TWC. An equivalent second order multi input single output (MISO) linear sub-space model is identified for the complex detailed
Due to climatic movements and politics, there is no doubt that a stricter emission legislation will soon face the two-wheeler sector and their manufacturers with new challenges. Additional to the already limited pollutants, a limitation of particulate number will probably also be introduced, which means that there is an urgent need for action in exhaust gas after treatment and particulate reduction systems. For natural aspirated, port injected engines, as used in two-wheeler-technologies, conventional systems already established in passenger cars are not necessarily applicable. Moreover, the emission spectrum is fundamentally different from passenger car engines due to the better homogenization of they typically used MPFI engine types. Adapting conventional particulate filter technologies to the finer particles of MPFI engines would result in a disproportionately larger exhaust backpressure. For this reason, we are investigating the effects of 3-way catalytic converters on particulate
The carbon footprint calculation of a catalytic converter coating process at Heraeus Precious Metals is presented in this publication. The emission hot spots are identified and discussed. Heraeus Precious Metals is a German world-wide leading company in the field of precious metal products and Tier-1 Supplier of emission catalytic converter coatings. In the first step of the carbon footprint calculation, all relevant raw materials and production process steps of the coating process are collected and modelled by use of a flowchart. In this case study the manufacturing of the metal honeycomb carrier is not included in the calculation. Transport emissions from the origin of the raw materials to the manufacturing plant of Heraeus Precious Metals in Germany are also considered in the carbon footprint calculation. Included activities for the production of the washcoat dispersion are the mixing of all components by use of an electric agitator and the grinding of the mixture by use of an
Emission Control has always been a major concern in each and every field. An increase in emissions leads to climate change, global warming, and even various diseases. The transportation system is responsible for around 30% of emission production, of which 70% of the total atmospheric burden comes from automobiles. Recently developed emission-free electric vehicles have positively affected the levels of impurity in the environment, yet the remaining Internal Combustion Engine (ICE) vehicles on the road have been left with unchecked emissions. Traditional Catalytic Converters are widely used to reduce the emissions of vehicles. It works on the principle of converting hazardous gases emitted from the engine to less harmful carbon dioxide (CO2), nitrogen (N2), and water (H2O). It is integrated with the exhaust of the engine. High efficiency and better emission control catalytic converters are still major milestones to achieve for automotive industries. For this purpose, a new approach is
Kinetic modelling of exhaust aftertreatment systems is a topic of extensive research in the automobile sector. This study represents the modelling of catalytic reactions on the surface of platinum dispersed diesel oxidation catalysts. In addition to oxidation reactions in the catalytic converter, a model for hydrocarbon adsorption/desorption on zeolite was adopted and validated with experimental results. The model was further used to simulate the experimental results at two different Pt loadings on the catalyst surface. The simulated results were observed to fit reasonably well with the experimental results at each Pt loading on the catalyst. The adsorption/desorption behaviour on the catalyst surface was found to be affected by Pt loading. The simulation results have shown that Pt atoms might have occupied the active site of zeolite which resulted in the reduction of adsorption/desorption rates. Less Pt loading has caused more storage sites on the zeolite surface and hence, higher
With the advent of BS VI regulations, automotive manufacturers are required to innovate the powertrains, fuel systems, exhaust and its after treatment systems to meet the regulatory requirements. The exhaust regulations can be met either by reducing the exhaust gases being generated by the engine (attacking the source) or by treating the exhaust gases in after treatment devices. The choice of the opted system varies with the manufacturer. The after-treatment devices such as catalytic converters are generally mounted in the engine compartment to take advantage of high temperature of exhaust gases to yield the reactions. Such an arrangement imposes a lot of thermal load on the peripheral components such as gearshift cables, bearings, oil seals, driveshafts etc. Thermal shields or thermal sleeve are used to address thermal issue and to protect transmission components. System level validation test requirement of transmission need to be re-visited considering change in environmental
Affordable, efficient and durable catalytic converters for the Commercial Vehicle and Non-Road industry in all countries are required to reduce vehicle emissions under real world driving conditions and fulfill future legal requirements. Specially for India traffic conditions and payload to engine size conditions new cost-effective solutions are needed to participate in a cleaner and healthier environment. Metallic substrates with structured foils like the Transversal StructureTM (TS) or the Longitudinal StructureTM (LS) have been proved to be capable of improving conversion behavior, even with smaller catalyst size. Now Vitesco Technologies is developed a new Substrate for Heavy duty applications that specifically maintains the geometric surface area at a very high level and improves further the mass transport of the pollutants, which potentially leads together to very high pollutant conversion rates. Together with active temperature management this solution will maintain a high
Gasoline engine control strategies ensure a combustion control around stoichiometry. That is because the three-way catalytic converter allows CO and HC oxidation under lean operating conditions while ensuring NOx reduction for rich mixtures. In case of engine malfunction, the controller must adapt to compensate for potential torque loss and other critical attributes, potentially leading to significant deviation of the fuel-air mixture richness from stoichiometry and higher emission levels. Therefore, during development of the engine fault diagnostics, the impact on the pollutant emissions must be considered. In this paper, a model-based development process is proposed. It is based on system simulation modelling techniques, where a complete exhaust line is represented in order to predict tail-pipe emissions under stoichiometric, lean and rich conditions, for engine control design purposes. Two different modelling approaches are applied and evaluated in this paper. First, a physics-based
The present work investigates a means of controlling engine hydrocarbon startup and shutdown emissions in a Wankel engine which uses a novel rotor cooling method. Mechanically the engine employs a self-pressurizing air-cooled rotor system (SPARCS) configured to provide improved cooling versus a simple air-cooled rotor arrangement. The novelty of the SPARCS system is that it uses the fact that blowby past the sealing grid is inevitable in a Wankel engine as a means of increasing the density of the medium used for cooling the rotor. Unfortunately, the design also means that when the engine is shutdown, due to the overpressure within the engine core and the fact that fuel vapour and lubricating oil are to be found within it, unburned hydrocarbons can leak into the combustion chambers, and thence to the atmosphere via either or both of the intake and exhaust ports. As well as shutdown it also affects the startup process, where higher hydrocarbon emissions are caused due to the forced
The three-way catalytic converter (TWC) is a vital component of the S.I. (Spark Ignition) engine to meet the current emission norms. TWC can perform the three conversion processes simultaneously. Hence, health diagnosis and performance monitoring of TWC is a major requirement of the power-train control system. In TWC modeling, the chemical species CO, THC, NOx, O2, and CO2 are the major components of the redox reaction over the wash-coat surface which impacts the overall conversion efficiency of the gases. This research work examines a generalized chemical model for a fresh catalytic converter validated for significant engine operating points in an urban drive cycle. The gas concentration measurements across the catalyst are harvested from an engine dynamo-meter test-bed. This work attempts to find the best method to optimize the chemical kinetic parameter of the Arrhenius equation parameters. An optimization framework is designed and has been tried on two different optimization
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