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Ammonia Measurement Investigation Using Quantum Cascade Laser and Two Different Fourier Transform Infrared Spectroscopy Methods

Caterpillar UK Ltd-Richard Barrett, Jim Baxter
Loughborough university-Nilton Li, Ashraf El-Hamalawi
  • Technical Paper
  • 2020-01-0365
To be published on 2020-04-14 by SAE International in United States
Most diesel engine exhausts have been fitted with SCR (Selective Catalyst Reduction) in order to reduce NOX (Oxides of Nitrogen) by using NH3 (ammonia). However, both NOX and NH3 have been classified as compounds hazardous for the environment and human health. If the reaction between NOX and NH3 is unbalanced during treatment, it can lead to either NOX or NH3 being released into the environment. Accurate measurement is thus necessary. QCL (Quantum Cascade Laser) and FTIR (Fourier Transform InfraRed) are two methods that have been used to measure NH3 and NOX directly in diesel engine exhausts. However, only a few studies have compared those two methods of NH3 measurement, mainly from diesel engine exhausts. The aim of this paper is to compare the QCL and 2 different FTIR specifications for NH3 measurement directly from diesel engine exhausts under well-controlled laboratory conditions. Researchers have found that as NH3 is reactive, it is absorbed inside the exhaust pipe if the probe location is some distance away from the SCR. The results reported here contradict this and show…
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MIMO Control of a Turbogenerator for Energy Recovery

Loughborough Univ.-Simon Petrovich, Kambiz Ebrahimi, Nikolaos Kalantzis, Antonios Pezouvanis
  • Technical Paper
  • 2020-01-0261
To be published on 2020-04-14 by SAE International in United States
Market trends for increased engine power and more electrical energy on the powergrid (3kW+), along University of Loughborough for fuel consumption improvements and emissions reduction, are driving requirements for component electrification, including turbochargers. GTDI engines waste significant exhaust enthalpy; even at moderate loads the WG (Wastegate) starts to open to regulate the turbine power. This action is required to reduce EBP (Exhaust Back Pressure). Another factor is catalyst protection, where the emissions device is placed downstream turbine. Lambda enrichment or overfuelling is used to perform this. However, the turbine has a temperature drop across it when used for energy recovery. Since catalyst performance is critical for emissions, the only reasonable location for an additional device is downstream of it. This is a challenge for any additional energy recovery, but a smaller turbine is a design requirement, optimised to operate at lower pressure ratios. A WAVE model of the 2.0L GTDI engine was adapted to include a TG (Turbogenerator) and TBV (Turbine Bypass Valve) with the TG in a mechanical turbocompounding configuration, calibrated with steady state…
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Vehicle Emission Solutions for China 6B and Euro 7

Umicore AutoCat (China) Co., Ltd.-Gu Weiwei
Umicore Autocat (China) Co., Ltd.-Xiangwei Meng
  • Technical Paper
  • 2020-01-0654
To be published on 2020-04-14 by SAE International in United States
Combinations of TWC (CC1) and coated gasoline particulate filters (CC2) were aged by 4 mode and fuel cut aging to simulate 160K kilometers of in-use aging China and Europe, respectively. The separate combinations of catalysts were then evaluated on two low emission engines using the WLTC driving cycle. Regarding the TWC CC1 catalysts both volume and PGM were varied. With respect to the gasoline particulate filters (GPF) OSC/washcoat amounts were varied at constant PGM loading. For European applications, after fuel cut aging, Euro6D emission target can be met with any combination of TWC + GPF catalysts. However, if the gaseous regulations for Euro 7 are similar to China 6B the TWC CC1 catalyst should be >1.0L in volume in order to meet CO and NOx emissions. For the Chinese applications, after the 4-mode aging again the TWC CC1 catalyst should be >1.0L in volume and high levels of OSC are needed in the GPF to meet CO and NOx emission targets. Results imply that TWC CC1 design is most critical and more washcoat (bigger volume)…
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Use of Nitric Acid to Control the NO2:NOX Ratio Within the Exhaust Composition Transient Operation Laboratory Exhaust Stream

Southwest Research Institute-Robert Henderson, Ryan Hartley, Cary Henry
  • Technical Paper
  • 2020-01-0371
To be published on 2020-04-14 by SAE International in United States
The Exhaust Composition Transient Operation Laboratory (ECTO-Lab) is a burner system developed at Southwest Research Institute (SwRI) for simulation of IC engine exhaust. The current system design requires metering and combustion of nitromethane in conjunction with the primary fuel source as the means of NOX generation. While this method affords highly tunable NOX concentrations even over transient cycles, no method is currently in place for dictating the speciation of nitric oxide (NO) and nitrogen dioxide (NO2) that constitute the NOX mixture. NOX generated through combustion of nitromethane is dominated by NO, and generally results in a NO2:NOX ratio of <5 %. Generation of any appreciable quantities of NO2 is therefore dependent on an oxidation catalyst to oxidize a fraction of the NO to NO2. Presented within this manuscript is a method for precise control of the NO2:NOX ratio within the ECTO-Lab exhaust stream by using nitric acid as the NOX precursor molecule in lieu of nitromethane. While decomposition of nitromethane generates NO as the dominate component of the NOX mixture, nitric acid decomposition produces primarily…
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Effect of geometry variations in a polymer electrolyte membrane fuel cell

Siemens Digital Industries Software-Carlo Locci, Chris Lueth, Huong Nguyen, Karin Frojd
  • Technical Paper
  • 2020-01-1174
To be published on 2020-04-14 by SAE International in United States
Water transport at high current densities is of main concern for polymer electrolyte membrane fuel cells. The water content of the membrane has to be high enough to provide maximum electrical conductivity and thus optimal stack performance. Dry-out may also lead to membrane degradation. However, a too high level of humidity leads to cell flooding, blocking the air and fuel flows to the catalyst sites and thus the reactions, resulting in a drop in efficiency. Fuel cells water transport physics requires further investigation due to its complexity [1,2] and numerical modelling can improve the fundamental understanding of the phenomena. In this work, an optimization algorithm is used to optimize a fuel cells geometry to improve the temperature distribution and the pressure drop. In addition, the effect of the several geometric configurations on the water management is discussed. The PEM fuel cell is modelled in Siemens Simcenter STAR-CCM+ [3]. Anode and cathode GDL and catalyst layers are modelled as porous media, with electrochemical reactions in the catalyst layer. The membrane is modelled as a solid block…
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Investigation Into Improved Low-Temperature Urea-Water Solution Decomposition by Addition of Titanium-Based Isocyanic Acid Hydrolysis Catalysts and Surfactant

Southwest Research Institute-Ryan Hartley, Nolan Wright, Cary Henry
University of Texas-Zachary Tonzetich
  • Technical Paper
  • 2020-01-1316
To be published on 2020-04-14 by SAE International in United States
Mitigation of urea deposit formation and improved ammonia production at low exhaust temperatures continues to be one of the most significant challenges for current generation SCR aftertreatment systems. Various technologies have been devised to alleviate these issues including: use of alternative reductant sources and thermal treatment of the urea-water solution (UWS) pre-injection. The objective of this work is to expand the knowledge base of a potential third option, which entails chemical modification of UWS by addition of titanium-based urea/isocyanic acid (HNCO) decomposition catalysts and/or surfactants to the fluid. Physical mixtures of urea and varying concentrations of ammonium titanyl oxalate (ATO), oxalic acid, and titanium dioxide (TiO2) were generated, and the differences in NH3 and CO2 production were evaluated. It was found that addition of 2.0 mol % ATO to urea increased CO2 production by 821 % and NH3 production by 96 % at temperatures ≤ 215 °C, indicating significantly enhanced hydrolysis of HNCO. Conversely, is was demonstrated that addition of oxalic acid or TiO2 to urea exhibited little effect on NH3 and CO2 production, indicating…
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Formation and Decomposition of Ammonium Nitrate on an Extruded Vanadium-based SCR Catalyst

Cummins Emission Solutions-Nathan Ottinger, Yuanzhou Xi, Christopher Keturakis, Z. Gerald Liu
  • Technical Paper
  • 2020-01-1320
To be published on 2020-04-14 by SAE International in United States
In this study, the formation and decomposition of ammonium nitrate (AN) on a state-of-the-art extruded vanadium-based SCR catalyst (V-SCR) under simulated exhaust conditions has been evaluated. Results show that AN readily forms and accumulates at temperatures below 200°C when exposed to NH3 and NO2. The rate of AN accumulation increases with decreasing temperature. A new low temperature NH3 storage site (not present following NH3 storage conditions with NH3 only) becomes apparent after AN accumulation at 100 and 125°C for an extended duration (e.g., t > 30 min). This new NH3 storage site, with a peak release temperature of approximately 185°C, is then evaluated in detail to better determine its origin. BET surface area, diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS), thermal gravimetric analysis (TGA), and reactor-based experiments are all used to characterize AN formed on the V-SCR catalyst in comparison to pure AN powder. Experiments on AN powder reveal that the new low temperature NH3 peak can be attributed to the release of NH3 bound to the accumulated AN, even though the thermal decomposition of…
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A Fundamental study on the effects of Electrically Heated Catalyst on State of Charge of the battery pack for a series hybrid electric vehicle at cold start.

NE Chemcat Corp.-Makoto Nagata
Waseda University-Suchitra Sivakumar, Hajime Shingyouchi, Xieyang Yan, Toshinori Okajima, Kyohei Yamaguchi, Jin Kusaka
  • Technical Paper
  • 2020-01-0444
To be published on 2020-04-14 by SAE International in United States
Battery models are recently being developed as one of a component of the powertrain system of Hybrid Electric Vehicle (HEV) to predict the State of Charge (SOC) accurately. The electric components like the Electrically Heated Catalyst (EHC) which is used to reach the catalyst light off temperature in advance are being employed in the powertrain of HEVs. The EHC draws power from the battery pack of the HEV. Therefore, sufficient energy should be stored in the battery pack of an HEV to power the auxiliary components in the powertrain. In a series hybrid electric vehicle system, the engine is primarily used to charge the battery pack. Therefore, it is important to develop a control strategy that triggers the engine start/stop conditions and reduces the frequency of engine operation to minimize the equivalent fuel consumption. A battery pack model was constructed in MATLAB-Simulink to investigate the SOC variation of a high-power lithium ion battery during extreme engine cold start conditions (-7°C) with and without the application of EHC. An electrically heated catalyst (EHC) was also simulated…
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Model Predictive Control of an Air Path System for Multi-Mode Operation in a Diesel Engine

Garrett Advancing Motion-Paul Dickinson, Jaroslav Pekar, MinSeok Ko
Hyundai Motor Group-Buomsik Shin, Yohan Chi, Minsu Kim
  • Technical Paper
  • 2020-01-0269
To be published on 2020-04-14 by SAE International in United States
A supervisory model predictive control system is developed for the air system of diesel engine. The diesel air system is complicated, composing of many components and actuators, with significant nonlinear behavior. Furthermore, the engine usually often operates in various modes, for example to activate catalyst regeneration like LNT or DPF. Model predictive control (MPC) is based on a dynamical model of the controlled system and it features predicted actuator path optimization. MPC has been previously successfully applied to the diesel air path control problem, however, most of these applications were developed for a single operating mode (often called normal operating mode) which has only one set of high-level set point values. In reality, each engine operating mode requires a different set of set point maps in order to meet the various system requirements such as, HP-EGR modes for cold start purposes, heat-up modes for after-treatment conditioning, rich operation for catalyst purging and normal modes. Air mass and its composition requirement are heavily depending on each specific mode. This large array of mode specific set points…
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Investigations Regarding Deposit Formation on Diesel Oxidation Catalysts

FEV Europe GmbH-Bernhard Lüers
Technical University of Braunschweig-Kevin Friese, Peter Eilts
  • Technical Paper
  • 2020-01-1432
To be published on 2020-04-14 by SAE International in United States
Deposit formation on components in the exhaust aftertreatment system is critical since RDE limits must be observed at any time. Besides, uncontrolled oxidation of carbonaceous deposits might damage the affected exhaust gas component. To comply with current and future emission standards diesel engines are usually operated with high EGR rates which leads to increased soot and hydrocarbon emissions what makes formation of carbonaceous deposits on EAT components more likely. With this background, a research project was carried out that investigates influencing parameters and mechanisms of deposit formation on DOCs. Within the project a reference driving cycle was developed in order to create deposits within short time. In further endurance runs the driving cycle was modified and the changes of the deposits’ properties were analyzed. Furthermore, the engine was operated using different fuels, monoliths and engine operation modes. The thermal stability of the deposits is highly affected be the engine operation mode and the engine load within the driving cycle. On the other hand the thermal stability of the deposits does not change in a single…