Browse Topic: Diesel exhaust emissions

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Neural Surrogates and Reinforcement Learning for Heavy-Duty Diesel Torque Control2026-01-01994/7/2026
Accurate torque-trace reproduction on regulatory drive cycles is central to heavy-duty diesel certification and development testing. Conventional controllers such as Proportional Integral Derivative (PID or PI) can be enhanced with gain scheduling and feedforward (FF) maps to satisfy requirements but require extensive calibration and are sensitive to nonlinearities and delay. This paper evaluates a data-driven control framework comprising a recurrent neural surrogate of engine torque (specifically an LSTM – long short-term memory) trained on engine/dynamometer data and a reinforcement learning (RL) policy trained using this surrogate (“world model”) to track requested torque while regularizing control effort. The RL policy (specifically TD3 – twin delayed deep deterministic) is benchmarked against tuned PID and PID+FF baselines on the Environmental Protection Agency’s Heavy Duty Federal Test Procedure (HD-FTP) segments using EPA regression criteria (slope, |intercept|, R2) and tracking metrics (mean absolute error - MAE, root mean square error - RMSE). TD3 reduced mean absolute error (MAE) by 58% (from 91.34 to 38.69 N·m) and root mean square error (RMSE) by 54% (from 123.5 to 56.73 N·m), improved regression to slope = .9978, |intercept| = 7.13 N·m, R2 = .9844, and cut the 95th-percentile absolute error by 60% compared to the PID+FF controller (the next best performing controller – in all categories). Results show the RL controller improves responsiveness and accuracy relative to autotuned PID+FF on the surrogate model, while reducing manual calibration effort. The approach is modular and engine-agnostic (retrain surrogate and policy) and is amenable to multi-objective extensions that incorporate emissions proxies in the reward.
Cook, James, Puzinauskas, Paulius, Bittle, Joshua, Hall, Spencer
Enhancing the Understanding of a State-of-the-Art Fe/zeolite Selective Catalytic Reduction Catalyst2026-01-03624/7/2026
Fe/zeolite selective catalytic reduction (SCR) catalysts are commercially used for NOx emissions reduction from diesel engines. In comparison to Cu/zeolite, these catalysts are widely reported to form less N2O as a byproduct of the SCR reactions. However, Fe/zeolite SCR is less active than Cu/zeolite for low temperature NOx conversion under standard SCR conditions. In this study, a state-of-the-art Fe/zeolite SCR catalyst is probed with a combination of N2 physisorption, SEM/EDX, reactor-based performance and active site quantification. Measurements investigate the impact of degreening, mild and extreme hydrothermal aging. In a degreened condition, the impact of water vapor on standard and fast SCR and isothermal desorption of NH3 is assessed. The Fe/zeolite catalyst’s hydrothermal durability is studied following hydrothermal aging at temperatures from 550°C up to 950°C. NH3 adsorption and temperature programmed desorption (TPD) and NO2 adsorption and TPD experiments are used to quantify the surface acidity and active Fe sites of the catalysts, respectively. Kinetic analysis of the standard SCR data is conducted to elucidate the mechanisms responsible for SCR activity loss upon hydrothermal aging. The authors believe the results presented herein can support the industry wide efforts to continue to improve diesel emissions control.
Ottinger, Nathan, Xi, Yuanzhou, Liu, Z. Gerald
Compact, Low-Cost Ultra-Low NOx Solution for 2027 US EPA, Euro VII, China VII and Off-Road2026-01-03634/7/2026
Achieving ultra-low NOx emissions remains a major challenge in diesel emission control industry worldwide, especially as increasingly stringent regulations are introduced globally. Selective Catalytic Reduction (SCR), the leading NOx reduction technology in diesel systems, performs best when “sufficient” heat and ammonia are made available to it. At the same time, any proposed solution must be both low-cost and functionally robust in an industry seeking near 100% NOx removal at the lowest feasible cost. This work presents a low-cost architecture, utilizing a small, highly compact, single heater-mixer unit along with a light-off (close-coupled) SCR for meeting most stringent NOx emission regulations worldwide. It also hinders deposit formation lowering warranty costs and mitigating failure modes. Engine studies using a fully-aged aftertreatment system demonstrate that the proposed solution enables compliance with newer heavy-duty regulations including 2027 US, Euro-VII, China-VII, and likely the upcoming Bharat-VII while also rendering a large ‘compliance margin’, providing significant margin for meeting in-use compliance.
Masoudi, Mansour, Poliakov, Nick
A Quantitative Approach for Mapping and Assessing Diesel Particulate Filter Regeneration Events in Diesel Engines2026-01-03774/7/2026
Regeneration of diesel particulate filters (DPFs) is crucial for maintaining the performance of diesel engines and minimizing harmful particulate matter (PM) emissions from exhaust. However, conventional regeneration strategies often suffer from incomplete soot removal and inefficient monitoring. These issues lead to increased exhaust back pressure, reducing engine efficiency, and potentially damaging the particulate filter. In this paper, an approach is proposed for mapping and quantifying the real-world DPF regeneration process for diesel engines complying with the stringent emission standards. We introduce a novel metric, the differential pressure drop percentage (DPDP), to detect regeneration events and quantify soot burn quality. The proposed method utilizes real-time sensor data obtained through the vehicle’s On-Board Diagnostics (OBD) system. The algorithm processes sensor data and robustly maps the regeneration quality. The performance of regeneration event detection and soot burn quality has been validated based on diagnostic trouble codes (DTCs) raised by the engine control unit (ECU). Our proposed method demonstrates that predictive maintenance can be used to manage strategies for diesel exhaust after-treatment systems, which can effectively reduce increased maintenance costs and operational downtime.
Bagga, Harleen Kaur, Nagare, Mukund B., Patil, Bhushan D., Ravishankar, Hariharan, Melapudi, Vikram, Vanderheide, Craig, Patil, Abhijit
Optimizing Diesel Emission Controls through Advanced Software Solutions for HC Desorb Fault in Diesel Oxidation Catalysts2026-26-00611/16/2026
After the implementation of BS-VI emission standards, effective exhaust after-treatment has become critical in minimizing harmful emissions from diesel engines. One significant challenge is the accumulation of hydrocarbons (HC) in the Diesel Oxidation Catalyst (DOC). Certain hydrocarbons may adsorb onto the catalyst surface yet remain unreactive, leading to potential operational inefficiencies. This phenomenon necessitates the desorption of unreactive hydrocarbons to allow space for more reactive species, thereby enhancing oxidation efficiency and overall catalyst performance. The process of desorption (DeSorb) is vital to maintaining the balance of reactive hydrocarbons within the DOC. When a vehicle is idling, unburnt fuel produces hydrocarbons that accumulate in the DOC. Upon acceleration, these hydrocarbons can lead to an uncontrolled rise in temperature, resulting in DOC push-out, catalyst damage, and downstream impacts on the Diesel Particulate Filter (DPF). To mitigate these risks, a dedicated software solution has been implemented to monitor HC levels and trigger a HC desorb mode. This proactive approach initiates regeneration before hardware failure occurs, ensuring the longevity of the DOC and maintaining compliance with emission regulations. This innovative approach not only addresses immediate operational concerns but also contributes to the broader goal of sustainable automotive engineering.
K, Sabareeswaran, K K, Uthira Ramya Bala, k, Janarthanan, A, Ravikumar, YS, Ananthkumar
Data-Driven Modeling for Emission Prediction and ATS Performance Benchmarking for Hydrogen and Diesel ICE Applications2026-26-03861/16/2026
This study presents a comprehensive methodology for benchmarking hydrogen and diesel internal combustion Engines, with emphasis on virtual Real-Drive Emission (RDE) test procedures for diesel and hydrogen application. Emission profiles for legal cycles and RDE scenarios are accurately predicted through integration and development of Artificial Neural Networks (ANN) based on Long Short-Term Memory (LSTM) models. Virtual evaluations of Selective Catalytic Reduction (SCR) system performance, Diesel Exhaust Fluid (DEF) dosing accuracy, and exhaust temperature dynamics enabled by integrated data pipelines and physics-based modeling are also explored for holistic prediction of output. Across models, validation demonstrates good prediction accuracy including temperature (R2 > 0.94, RMS error < 25°C), air flow (92% accuracy, RMSE = 28 kg/h), upstream NOx (93% accuracy, RMSE < 10 mg/s), and SCR (TP NOx accuracy = 91.82%, dosing accuracy = 87.73%). This approach has the potential to offer significant reduction in the need of extensive on-road driving tests, as the model provides capability to emulate the same, thereby lowering development costs and supporting OEMs in meeting stringent emission standards through efficient benchmarking of Aftertreatment systems (ATS).
Shah, Jash Vipin, S, Manoj Kumar, Ratnaparkhi, Aditya, H, Shivaprakash
Mitigating Urea Deposits in Selective Catalytic Reduction Systems through Software Control for Improved Performance in Low Duty Cycle Operations2026-26-04241/16/2026
In the pursuit of achieving stringent BS VI emission standards, maintaining the efficiency of Selective Catalytic Reduction (SCR) systems is paramount, especially in vehicles operating under low duty cycles. A significant concern in such scenarios is the accumulation of urea deposits within the SCR, which can lead to detrimental push-out effects and compromised catalyst performance. This issue is particularly prevalent during low-temperature operations, where the conditions are less favorable for the effective conversion of nitrogen oxides (NOx). To address this challenge, an innovative software control system has been developed to monitor operating conditions and detect potential urea deposit faults. The software continuously evaluates parameters such as temperature and vehicle duty cycle, identifying conditions that may lead to urea crystallization within the SCR system. When unfavorable conditions are detected, the software triggers a fault alert that activates a regeneration process aimed at dissolving the accumulated urea deposits. This proactive approach not only prevents the adverse effects of urea buildup but also ensures the continued efficiency of the SCR system in reducing NOx emissions. By facilitating timely regeneration, the software enhances the operational reliability of the SCR catalyst, thereby supporting compliance with regulatory standards.
K, Sabareeswaran, K K, Uthira Ramya Bala, Raju, Manikandan, K J, Ramkumar, YS, Ananthkumar
Multi-Objective Optimization and Reduced-Order Modeling for Aftertreatment System Performance Prediction2026-26-04261/16/2026
As emission regulations grow increasingly stringent, aftertreatment system designs are becoming more complex, requiring robust performance across the full range of Engine Operating Points (EOPs). Traditionally, aftertreatment development has relied on Computational Fluid Dynamics (CFD) simulations conducted at a limited set of representative points, focusing primarily on single performance objectives such as minimizing back pressure, enhancing ammonia uniformity, or reducing Diesel Exhaust Fluid (DEF) deposits. However, these objectives are inherently interdependent, and optimizing for a single parameter often negatively impacts others, leading to suboptimal system performance across the full engine map. To address these challenges, this paper presents a multi-objective optimization framework combined with a reduced-order modeling approach to predict aftertreatment system behavior across the full engine operating range. The methodology captures the interactions among various performance parameters, providing a more holistic basis for system evaluation and design decisions. By integrating multi-objective optimization with predictive modeling, the approach improves analysis efficiency and supports more informed design trade-offs compared to traditional single-objective, limited-point simulations.
Nanduru, Enoch, Willey, Donald, Udhane, Tushar Sudam, Giri, Nikhil, Chourasiya, Anshul, Pal, Yash
A Low Pressure Pumpless DEF Dosing System by using Compressed Air and an Air Assisted DEF Injection Nozzle2026-26-02191/16/2026
The study emphasizes on development of Diesel Exhaust Fluid (DEF) dosing system specifically used in Selective Catalytic Reduction (SCR) of diesel engine for emission control, where a low pressure pumpless DEF dosing system is developed, utilizing compressed air for pressurizing the DEF tank and discharging DEF through air assisted DEF injection nozzle. SCR systems utilize Diesel Exhaust Fluid (DEF) to convert harmful NOx emissions from diesel engines into harmless nitrogen and water vapor. Factors such as improper storage, handling, or refilling practices can lead to DEF contamination which pose significant operational challenges for SCR systems. Traditional piston-type, diaphragm-type, or gear-type pumps in DEF dosing systems are prone to mechanical failures leading to frequent maintenance, repairs, and costly downtimes for vehicles. To overcome the existing challenges and to create a more reliable and simple DEF delivery mechanism the pumpless DEF Dosing system is developed. The system includes a completely sealed DEF tank, pressurized to a calibrated system pressure, by connecting the tank entry line to compressed air. Signal from the Engine Control Unit is provided to the metering valve positioned in the delivery line which controls the quantity to be dosed. Pressure reducing valve, quick relief valve and pressure sensor for feedback are integrated, with the tank and the metering valve to develop a completely reliable DEF dosing system. The system has been modelled in MATLAB and tested for different operating pressure, height and volume of the tank and by varying the signals provided to the metering unit. Overall, we can conclude that the pumpless DEF dosing system is a simplified version among the existing DEF dosing practices. When implemented it provides significant reduction in cost, complexity, repair and maintenance of the system eliminating the challenges and failures posed by the existing pump-based dosing systems.
M, Hareni, Giridharan, Jyothivel, A.l, Suresh, V, Yuvaraj, Rajan, Bharath
Development of a Cost-Effective DCU for Diesel Emission Control: Design, Diagnostics, and Compliance2025-28-028611/6/2025
The Dosing Control Unit (DCU) is a vital component of modern emission control systems, particularly in diesel engines employing Selective Catalytic Reduction technology (SCR). Its primary function is to accurately control the injection of urea or Diesel Exhaust Fluid (DEF) into the exhaust stream to reduce nitrogen oxide (NOₓ) emissions. This paper presents the architecture, operation, diagnostic features, and innovation of a newly developed DCU system. The Engine Control Unit, using real-time data from sensors monitoring parameters such as exhaust temperature, NOₓ levels, and engine load, calculates the required DEF dosage. Based on DEF dosing request, the DCU activates the AdBlue pump and air valve to deliver the precise quantity of diesel exhaust fluid needed under varying engine conditions. The proposed system adopts a master-slave configuration, with the ECU as the master and the DCU as the slave. The controller design emphasizes cost-effectiveness and simplified hardware, and software architecture compared to commercial counterparts. Additionally, it integrates diagnostic functions compliant with On-Board Diagnostics (OBD) and Unified Diagnostic Services (UDS) standards to detect system anomalies such as blockages, leaks, and electrical faults (e.g., short to ground or battery). By combining accurate dosing with advanced diagnostics, the DCU enhances SCR system efficiency, fuel economy, and compliance with strict emission norms. Test bench and simulation results confirm that the developed controller meets international emission and diagnostic standards. This positions the DCU as a significant contributor to cleaner, more efficient, and sustainable automotive technologies.
Raju, Manikandan, K, Sabareeswaran, K K, Uthira Ramya Bala, Krishnakumar, Palanichamy, Arumugam, Arunkumar, YS, Ananthkumar
Predicting Transient Soot Emissions in Diesel Engines Using Physical and Machine Learning Models2025-32-001711/3/2025
In recent years, diesel engine emissions regulations have been strengthened worldwide, necessitating the evaluation of regulatory values under transient conditions. Consequently, the need to assess transient states in the development of diesel engines has increased significantly. The evaluation using MBD (Model Based Development) is considered a promising method for achieving both low fuel consumption and simultaneous reduction of NOx and soot emissions. However, the mechanism of soot formation is complex, making it challenging to model mathematically directly. In this paper, hybrid machine learning approaches combining a physical model and a machine learning model are used to validate the prediction of soot emissions under transient conditions in a diesel engine with an EGR system. Various parameters such as fuel consumption and emissions predicted by the physical model are compared with measurements to validate the accuracy of the physical model. The prediction of soot emissions by the physical model is based on the Hiroyasu model. From these results, it is demonstrated that the physical model has sufficient accuracy to be used in hybrid machine learning approaches. However, it is shown that the physical model is inadequate as a prediction approach for soot emissions. Gaussian Process Regression (GPR), Support Vector Regression (SVR), Random Forest (RF), and Gradient Boosting Decision Tree (GBDT) are used to develop the machine learning models, and each model is trained on data under steady-state conditions. The prediction accuracy of each model and the physical model is compared and validated. The results show that the hybrid machine learning approaches have higher predictive accuracy than the physical model for soot emissions predictions in both steady-state and transient conditions. The GPR model with the highest prediction accuracy shows a test R2 of 0.87 under steady-state conditions and relative errors with the measured values of less than 10% for both Non-load Transient Cycle (NRTC) and Low Load Cycle (LLC), which are engine test cycles.
Kitamura, Takahiro, Matsuoka, Ayano, Suematsu, Kosuke, Okano, Hiroaki
Probabilistic Thermal Modelling of AdBlue System Using Bayesian Networks2025-28-037010/30/2025
In Diesel engine exhaust after treatment system (ATS), Nitrogen Oxides (NOx) emissions control is achieved via Selective Catalytic Reduction (SCR) in which AdBlue or Diesel Exhaust Fluid (DEF) plays vital role. But AdBlue freezes below -11°C due to which in cold climate conditions system performance becomes critical as it affects efficiency as well as overall performance leading to safety and compliance with emission standards issue. So, it is essential to have a probabilistic thermal model which can predict the AdBlue temperature as per ambient temperature conditions. The present paper focuses on developing Bayesian Network (BN) based algorithm for AdBlue system by modelling probability of key factors influencing on its performance including AdBlue temperature, Ambient temperature, Coolant temperature, Coolant flow, Vehicle operating conditions etc. The BN Model predicts and ensures continuous learning and improvement of the system, based on operational data. Methodology proposed in the paper aims to demonstrate a probabilistic model that captures the interactions affecting the AdBlue system's thermal behavior.
Thakur, Shivam, Salunke, Omkar
Condensate Formation in Exhaust Systems during Cold Start2025-24-00819/7/2025
In order to minimize tailpipe emissions of vehicles with combustion engines, highest conversion rates of exhaust gas aftertreatment systems are indispensable. At low ambient temperatures, gaseous emissions increase due to inhomogeneous mixture formation and incomplete combustion. Simultaneously, formation of condensate on exhaust gas-carrying components is stimulated due to temperatures dropping below the dew point. The acidic condensates contain more than 95 vol.-% water and a small fraction of aliphatic and aromatic hydrocarbons. In acidic environments these hydrocarbons can be polymerized, forming insoluble deposits that become progressively less reactive with time. These deposits may harm components of exhaust systems by fouling. As low temperature conditions are particularly promoting condensate formation, the aim of this study is to investigate condensate formation and composition during cold start and early warm-up phases in the exhaust duct of state-of-the-art internal combustion engines. Exhaust gas condensate of a diesel engine, a gasoline engine and a hydrogen engine (H2-ICE) is collected under various test conditions using an intensive cooler. Air- and engine coolant conditioning test benches enabling transient engine operation are used to provide realistic cold start conditions. Condensate composition and acidity is analyzed using a pH sensor, ion chromatography (IC), Karl Fischer titration, and gas chromatography coupled with mass spectrometry (GC-MS). Exhaust gas composition is analyzed using FTIR-spectrometry and a conventional exhaust gas analyzer. The correlation between condensate composition, exhaust gas composition and fuel composition is examined. Under comparable conditions, more condensate is generated in gasoline exhaust gas than in diesel exhaust gas. The investigations show a strong dependency of condensate acidity (pHcondensate,Gasoline ≈ 2 vs. pHcondensate,Diesel ≈ 3) on nitrogen oxide concentration in the exhaust gas. A calculation tool reveals that raw diesel exhaust gas generally has a lower (<41 °C) but more transient dew point temperature than raw gasoline exhaust gas (>41 °C).
Knapp, Sebastian, Hagen, Fabian P., Wagner, Uwe, Bockhorn, Henning, Trimis, Dimosthenis, Koch, Thomas
Influence of the SCR Reactivity on Passive Soot Oxidation for Vanadium-Coated and Uncoated (S)DPF2025-24-00869/7/2025
In modern diesel exhaust aftertreatment systems (EATS), combining a catalytic coating for selective NOx reduction (SCR) with a diesel particulate filter (DPF) enables simultaneous particulate filtration and NOx reduction. In such systems, soot regeneration is primarily influenced by the NO2 supply in the exhaust gas, particularly at low exhaust temperatures (250-400 °C). Several investigations found that in SCR-coated filters with urea-water solution (UWS) dosing upstream, particle oxidation is partially inhibited by NH3. However, at higher temperatures (>400 °C), this effect seems to be reduced. In this study, numerical modelling approaches based on engine test bench results are utilised to examine the impact of SCR reactivity on passive soot oxidation for a highly porous vanadium-coated SDPF. To identify the interaction mechanism between the SCR reaction and soot oxidation, further investigations were conducted using a filter with a washcoat without SCR-active component. The methodology for determining the reduction of soot oxidation with UWS dosing is based on measuring the CO concentration difference across the particulate filter. The experimental data were determined on a state-of-the-art 13.5-litre six-cylinder rail engine under varying operating conditions, including different soot loadings, UWS injection rates and temperatures. Results show significant reductions in passive soot oxidation rates at both low and high temperatures when NH3 is present. The diffusion of NO2 in the filter wall appears to be the determining factor for the reduction, indicating that the NO2 difference after and before the filter is not the only determining factor for the diffusion effect, but rather the concentration gradient in the filter wall. The findings highlight the complex interaction between SCR reactions and passive soot oxidation. Optimising the design of the EATS can avoid critical soot loads for many applications of particulate filters with SCR activity, even without active regeneration.
Prchal, Niklas, Wegmann, Andreas, Müller, Werner, Günthner, Michael
Experimental Investigations on the Effects of Injector Design and Operating Parameters on PCCI Combustion in a Light-Duty Diesel Engine03-18-04-00267/9/2025
Due to increasingly stringent emission regulations, advanced combustion strategies, such as premixed charge compression ignition (PCCI), have emerged promising solutions for achieving low NOx and soot emissions. However, challenges such as increased unburned hydrocarbon (HC), carbon monoxide (CO) emissions, and a restricted engine operating load range remain unsolved. Since conventional diesel engines are not inherently designed for PCCI operation, re-optimizing engine parameters is essential. The primary objective of this work is to investigate the influence of injector orientation and nozzle spray angle on combustion parameters, performance, and emissions in a PCCI diesel engine. Initial parametric studies revealed that early direct injection combined with high fuel injection pressure limited the PCCI load range to 30% and 60% of the rated capacity with diesel, without and with EGR, respectively, accompanied by higher HC and CO emissions. To address these limitations, the injector orientation is modified from inclined to vertical, increasing the offset from 5 to 9 mm and employing symmetric spray angles along the z-axis. The experiments were conducted at a constant engine speed of 1500 rpm with varying load conditions at optimized timing in PCCI mode to investigate the effect of injector orientation, offset, and spray angle. The results demonstrate two positive aspects: first, the load range extended from 30% to 40% of the rated load with diesel, with improved engine brake thermal efficiency and reduced NOx emission up to 85.6% compared to conventional diesel combustion (CDC). Second, while using the EGR, the load range extends from 60% to 62.5%, achieving up to 96% NOx reduction compared to CDC. Although HC and soot increased significantly, a notable decrease in HC was observed at higher loads compared to lower load conditions. According to this study, injector orientation and nozzle spray angle variation are effective strategies for enhancing the performance and extending the operating load range of PCCI engines.
Ranjan, Ashish Pratap, Krishnasamy, Anand
Experimental and Kinetic-Modeling Study of Ammonia/n-Heptane Combustion13-06-03-00204/9/2025
In recent years, researchers have increasingly focused on ammonia–diesel dual-fuel engines as a means of reducing CO2 emissions. Analyzing in-cylinder combustion processes is essential for optimizing the performance of ammonia–diesel dual-fuel engines. However, there is currently a lack of suitable reaction kinetics models for ammonia–diesel engine conditions. In this study, the ignition delay of ammonia/n-heptane mixtures was measured, and a reduced chemical mechanism was developed. Using rapid compression machine (RCM) experiments, the ignition delays of ammonia/n-heptane mixtures with different ammonia energy fractions (AEFs) (40%, 60%, and 80%) were measured. The test pressure ranged from 1.5 to 3.0 MPa, while the temperature ranged from 667 to 919 K, with an equivalence ratio of 1. The results showed that as the AEFs increased, the ignition delay of the premixed mixture also increased. When the AEF was 40%, the ammonia/n-heptane premixed mixture exhibited the negative temperature coefficient (NTC) phenomenon in the temperature range of 690 to 830 K. This phenomenon weakened as the AEF increased. Based on the experimental results, a reduced chemical mechanism for ammonia/n-heptane was developed, consisting of 162 species and 755 reactions. This model was able to accurately predict the ignition delay and laminar flame speed of ammonia/n-heptane mixtures, while reducing computational time by 94% compared to the detailed mechanism. When applied in three-dimensional simulations, this model effectively predicted the combustion and emission trends of ammonia–diesel engines. Advancing the first injection timing resulted in a decrease in NH3 concentration near the wall. The fuel injected during the first combustion injection increased the temperature near the wall, promoting the thermal decomposition of ammonia.
Cai, Kaiyuan, Liu, Yi, Chen, Qingchu, Qi, Yunliang, Li, Li, Wang, Zhi
Experimental and CFD Simulation Study of Heated and Cold Diesel Exhaust Fluid Spray Characteristics2025-01-84864/1/2025
This paper investigates heated and cold Diesel Exhaust Fluid (DEF) sprays with the aim of establishing the effect of temperature on the resulting spray characteristics. The work is motivated by the need to optimize active Selective Catalytic Reduction (SCR) systems to meet more stringent nitrogen oxide (NOx) emission regulations for internal combustion engines. Pre-heating DEF has the potential to improve evaporation of the injected fluid, increasing the NOx conversion efficiency of the SCR at low exhaust temperatures. Experiments are carried out using the MAHLE SmartHeat fluid heater and mounted atop a DEF injector, with an incorporated thermocouple for fluid temperature. The fluid temperature established by the heater in this configuration was about 130 °C. The fluid is injected into an atmospheric environment and Schlieren imaging is used to visualize the spray evolution. CFD simulations are also carried out to validate the experimental observations and further shed light on the associated velocity field. With respect to the spray characteristics, the results show that the most significant difference between cold and heated DEF sprays occurs when the heated fluid experiences flash boiling prior to injection. This flash boiling is thought to arise from occasional overheating near the heating surfaces. Under conditions of normal hot liquid DEF injection, only a slight improvement in the atomization pattern is observed. The merit of the heating is expected to be more pronounced in the subsequent evaporation of the droplets. With respect to the simulations, it was found that the predicted penetration depths agree with the experimental observations. The observed pronounced differences between the characteristics of the cold and hot spray with flash boiling as well as the limited improvements of the hot liquid spray characteristics are explainable by considering their Reynolds and Weber numbers.
Liu, Zeyang, Peters, Nathan, Bunce, Mike, Pothuraju Subramanyam, Sai, Akih Kumgeh, Benjamin
Neural Network Based Modeling and Model Predictive Control for Reduction in Diesel Emissions2025-01-83694/1/2025
The paper illustrates the process and steps in the development of a neural network-based economic Model Predictive Control (MPC) strategy for reducing diesel engine feed gas emissions. This MPC controller performs fuel limiting and modifies intake manifold pressure and exhaust gas recirculation (EGR) rate set-points to the inner loop air path controller to reduce engine-out oxides of nitrogen (NOx) and Soot emissions. We examine two Recurrent Neural Network (RNN) options for a control-oriented emissions model which are based on a multi-layer perception (MLP) architecture and a long short-term memory (LSTM) architecture. These RNN models are trained for use as prediction models in MPC. Both models are defined in input-output form, assuming that measurements/estimates of current values of NOx and Soot are available. We discuss and compare their training using PyTorch. The formulation of economic MPC is detailed, including the definition of the cost function and soft constraints. Approaches based on interior point methods and sequential quadratic programming for the numerical solution of the underlying optimization problem in MPC are summarized. Closed-loop simulations of the control system and the plant model in GT-Power demonstrate that both methods have the capability to shape engine-out emissions effectively by adjusting weights and constraints in the economic MPC formulation. The solutions with MLP-based and LSTM-based RNN are then compared based on several aspects such as model complexity, training time, tuning, closed-loop performance, and execution time. The closed-loop performance in terms of cumulative NOx and Soot exceeding soft constraints is compared based on Pareto fronts for the respective controller options. Methods to reduce online runtime are also studied. The results highlight the tradeoff between NOx and Soot emissions, and that better open-loop prediction accuracy achieved with the LSTM Neural Network model compared to the MLP model does not necessarily translate into better closed-loop performance when used as a part of the MPC controller.
Zhang, Jiadi, Li, Xiao, Kolmanovsky, Ilya, Tsutsumi, Munechika, Nakada, Hayato
Formation and Decomposition of Ammonium Sulfate Species over a Small Pore Cu/Zeolite Catalyst2025-01-84934/1/2025
Cu/zeolite selective catalytic reduction (SCR) catalysts are used globally to reduce NOx emissions from diesel engines. These catalysts can achieve high NOx conversion efficiency, and they are hydrothermally durable under real world diesel exhaust environments. However, Cu/zeolite catalysts are susceptible to sulfur poisoning and require some type of sulfur management even when used with ultra-low sulfur diesel (ULSD). In the present study, the authors seek to better illuminate the chemical processes responsible for ammonium sulfate formation and decomposition occurring in Cu/zeolite SCR catalysts. Reactor-based experiments are first conducted with a real-world concentration of SO2 (0.5 ppmv) and a typical diesel exhaust water vapor concentration (7 vol.%) to quantify progressive effects of ammonium sulfate formation. A second group of experiments probe the chemical decomposition of ammonium sulfate via NO titration. The “movement” of sulfate species during this process is monitored with temperature programmed desorption experiments. Finally, the effect of NO2 on ammonium sulfate is investigated via either co-feeding during ammonium sulfate formation or post-feeding following ammonium sulfate formation, since it is expected that NH3, SO2, and NO2 will all be present at the catalyst surface during real-world operation. The authors believe the results presented herein can support the broad research effort to continue to improve low temperature NOx conversion which is notably degraded by the formation of ammonium sulfate species.
Ottinger, Nathan, Xi, Yuanzhou, Liu, Z. Gerald
The Impact of GCI Engines on Long-haul Trucks in the US and China2025-01-83964/1/2025
This study evaluates the impacts of the gasoline compression ignition (GCI) engine on heavy duty long-haul trucks in both the Chinese and US markets. The study examines various aspects such as vehicle performance requirements, fuel consumption, emissions, and ownerships costs, and how they influence the implementation and impact of new technologies in these markets. By considering a wide variety of drive cycles, including standard regulatory cycles and real-world cycles, the study aims to identify the impact of varying degrees of powertrain electrification using diesel and GCI engines on fuel consumption and emissions. Additionally, this paper explores the viability of powertrain electrification in long-haul trucks by analyzing factors such as levelized cost of driving (LCOD), manufacturing costs, and energy costs. These considerations play a crucial role in determining the economic feasibility and attractiveness of electrification technologies in various driving scenarios and market contexts. The analysis results showed that the implementation of GCI engines in heavy-duty long-haul trucks requires consideration of market conditions, emissions regulations, and fuel prices. The GCI engines achieve remarkable NOx emissions reductions, exceeding 75% in the U.S. and 90% in China, making them a compelling choice for markets prioritizing stringent emissions standards. The LCOD analysis reveals that GCI engines remain competitive, with cost performance strongly influenced by diesel, urea, and gasoline prices. Moreover, GCI engines, when paired with hybrid architectures, deliver notable energy cost advantages, underscoring their potential to outperform conventional powertrains in the long term. Overall, the GCI engine emerges as a highly promising solution for heavy-duty long-haul trucks, offering substantial benefits in emissions, fuel economy, and operational costs. Its integration into electrified powertrain systems further enhances its appeal, solidifying its position as a forward-looking technology poised to meet the demands of evolving market and regulatory landscapes.
Nieto Prada, Daniela, Vijayagopal, Ram, Yan, Ziming, Sari, Rafael, He, Xin
Prediction of Diesel Engine NO x Transient Emissions Based on a Combined Model with Convolutional Neural Network–Efficient Channel Attention–Bidirectional Gated Recurrent Unit03-18-02-00122/6/2025
Widely used as power equipment, diesel engines emit NO x , which significantly threatens the well-being of both the ecosystem and individuals. The SCR system, which is employed to reduce NO x emissions from diesel engines, relies on precise control of the NO x emission levels. Addressing the challenge that traditional NO x emission prediction methods struggle to accurately forecast the emissions under transient operating conditions, this article introduces a deep learning model that integrates CNN, ECA, and BIGRU. The model’s necessary experimental data were collected during the hot phase of the WHTC, and input parameters were screened through correlation analysis. The model employs a CNN for feature extraction, integrates an ECA module to refine key feature processing, and utilizes BIGRU to capture temporal dynamics and dependencies, yielding predictive outcomes. Additionally, the model employs the Adam optimizer and combines it with BWO to adjust hyperparameters, thereby elevating the model’s accuracy for predicting transient NO x emission. Comparative analysis with existing CNN, LSTM, and CNN–LSTM models revealed that CNN–ECA–BIGRU model had a notable reduction in MAE, RMSE, and MAPE, along with an enhanced R 2 value. These improvements highlight the model’s superior predictive accuracy and its robust nonlinear fitting ability.
Peng, Yunlong, Wang, Guiyong, Wang, Yuhua, Wang, Feiyang, Wang, Zhiyuan, He, Shuchao
Diesel Exhaust Fluid (DEF) Associated Corrosion Risk Prediction for Aftertreatment System2024-28-025812/5/2024
With emission regulations becoming increasingly stringent, the integration of Diesel Exhaust Fluid (DEF) in aftertreatment systems has become essential for reducing nitrogen oxide (NOx) emissions in compliance with these evolving standards. DEF dosing is a very critical component in Selective Catalytic Reduction (SCR) systems, where it chemically reacts with NOx in the exhaust stream to form harmless nitrogen and water vapor, thus significantly reducing the environmental impact of diesel engines. However, the introduction of DEF presents a challenge of corrosion risk within the aftertreatment system components. This study aims to predict the location of corrosion, and its risk associated with DEF usage in Diesel aftertreatment system, by employing a multi-faceted approach that includes physical testing and computational modelling. Specifically, the focus of this paper is on predicting corrosion locations from unsteady DEF spray analysis without modelling detailed corrosion chemistry mechanism using computational fluid dynamics (CFD). This unsteady DEF spray analysis focuses on characterizing the spray behavior, its interactions with the reactor walls, and identifying key factors in DEF spray dynamics that can predict potential corrosion locations within the decomposition reactor tube (DRT). The DRT is a critical component in the aftertreatment system, serving as the conduit through which DEF spray is injected and transported to the SCR section. The key factors for prediction of corrosion locations include temperature of solids, film velocity, DEF concentration and direct DEF spray impingement zones. The criteria of these factors are studied, and relationships are established among these factors to provide insight into potential corrosion risk locations in DRT. This paper also discusses the approaches to speed the simulation and reduce the turnaround time to help make the design-development decision faster. The validation of simulation methodology through physical testing has shown a good correlation. This good agreement between simulation and experimental results underscores the effectiveness of simulation methodology in accurately identifying the potential corrosion locations.
Udhane, Tushar Sudam, Nanduru, Enoch, Warwick, Michael, Willey, Donald, Giri, Nikhil, Parikh, Tanishq
Dynamic Modeling of Torque & Emissions: Digital Twin to Simulate Combustion Process and Exhaust Emissions for Diagnostics & Prognostics Applications2024-28-017212/5/2024
As a journey to green initiatives, one of the focus areas for automotive industry is reducing environmental impact especially in case of internal combustion engines. Latest digital twin technology enable modelling complicated, fast and unsteady phenomena including the changes of emission gases concentration and output torque observed during diesel emission and combustion process. This paper presents research on the emission and combustion characteristics of a heavy vehicle diesel engine, elaborating an engineered architecture for prognostics/diagnostics, state monitoring, and performance trending of heavy-duty vehicle engine (HDVE) and after treatment system (ATS). The proposed architecture leverages advanced modeling methodologies to ensure precise predictions and diagnostics, using data-driven techniques, the architecture accurately model’s engine and exhaust system behaviors under various operating conditions. For exhaust system, architecture demonstrates encouraging predictive performance in estimating engine/tailpipe NOx-emissions. This development introduces novel method for calculating health scores, particularly for Selective Catalytic Reduction (SCR) systems which enhances diagnostic capabilities, enabling early detection of issues such as reduced conversion efficiency. By accurately predicting emissions and identifying potential problems early, the architecture helps ensure compliance with regulatory requirements. Additionally, the architecture considers vehicle dynamics, especially in the context of drivetrain health. The Nonlinear Autoregressive with Exogenous Inputs (NARX) model for torque estimation is crucial for understanding the dynamic behavior of the engine and its impact on overall vehicle performance. By monitoring and analyzing deviations in predicted torque, the architecture provides insights into the health and performance of the drivetrain, facilitating timely interventions and maintenance actions to ensure optimal vehicle dynamics and reliability. This study presents an architecture that integrates emission and vehicle dynamics models with prognostics health asset framework offering a holistic approach to predictive maintenance for HDVE and ATS
Singh, Prabhsharn, Thakare, Ujval, Hivarkar, Umesh
Deep Reinforcement Learning Based Application of Exhaust Gas Aftertreatment Control Using the Example of a Hydrogen Engine2024-24-00439/18/2024
Growing environmental concerns drive the increasing need for a more climate-friendly mobility and pose a challenge for the development of future powertrains. Hydrogen engines represent a suitable alternative for the heavy-duty segment. However, typical operation includes dynamic conditions and the requirement for high loads that produce the highest NOx emissions. These emissions must be reduced below the legal limits through selective catalytic reduction (SCR). The application of such a control system is time-intensive and requires extensive domain knowledge. We propose that almost human-like control strategies can be achieved for this virtual application with less time and expert knowledge by using Deep Reinforcement Learning. A proximal policy optimization (PPO) -based agent is trained to control the injection of Diesel exhaust fluid (DEF) and compared with the performance of a manually tuned controller. The performance is evaluated based on the restrictive emission limits of a possible EURO7-framework and DEF consumption. Applied to a standardized driving cycle (WHTC) and compared with the conventional application, the agent reaches similar emission values with a equally high DEF consumption. In addition, a long short-term memory (LSTM) network is trained to substitute the 1D-SCR-model and then used to train a PPO-based agent. The results of the agent interacting with the conventional 1D-model are compared to the results with the LSTM-network as environment. The results demonstrate, that the control of an exhaust gas aftertreatment system using Reinforcement Learning is very satisfactory. Further work is required to refine the proposed methodology into a fully-fledged tool for application in powertrain development.
Itzen, Dirk, Angerbauer, Martin, Hagenbucher, Timo, Grill, Michael, Kulzer, Andre
Comparing Physical and Chemical Properties of Soot from Laboratory Tests and Heavy-Duty Engines Used in Field Operations04-18-01-00028/2/2024
Morphology, nanostructure, and composition of soot extracted from the oil sump of different heavy-duty engines operated under dynamometer and field conditions were investigated. Soot characteristics were then compared to a carbon black sample. Soot was extracted from used oil for transmission electron microscopy (TEM) analysis. Energy-dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) analyses were also performed to assess soot composition. Two soot classes, I and II, can be identified based on their appearance under the TEM. Carbon black and class I particles have graphitic structures, while class II samples have a more sludge-like appearance. Similar aggregate sizes were observed among the samples. In all samples, the primary particle size distribution ranges from 16 nm to 22 nm in terms of mean diameter. Differences in the length and tortuosity of the graphitic fringes between the samples were observed. The findings suggest a greater degree of interaction between class II samples and the lubricating oil, and consequently, a different wear behavior may be expected depending on the specific soot characteristics.
Pacino, Andrea, La Rocca, Antonino, Cairns, Alasdair, Fay, Michael W., Smith, Joshua, Berryman, Jacqueline, Fowell, Mark
Optimizing Fuel Injection Timing for Multiple Injection Using Reinforcement Learning and Functional Mock-up Unit for a Small-bore Diesel Engine03-17-06-00415/3/2024
Reinforcement learning (RL) is a computational approach to understanding and automating goal-directed learning and decision-making. The difference from other computational approaches is the emphasis on learning by an agent from direct interaction with its environment to achieve long-term goals [1]. In this work, the RL algorithm was implemented using Python. This then enables the RL algorithm to make decisions to optimize the output from the system and provide real-time adaptation to changes and their retention for future usage. A diesel engine is a complex system where a RL algorithm can address the NOx–soot emissions trade-off by controlling fuel injection quantity and timing. This study used RL to optimize the fuel injection timing to get a better NO–soot trade-off for a common rail diesel engine. The diesel engine utilizes a pilot–main and a pilot–main–post-fuel injection strategy. Change of fuel injection quantity was not attempted in this study as the main objective was to demonstrate the use of RL algorithms while maintaining a constant indicated mean effective pressure. A change in fuel quantity has a larger influence on the indicated mean effective pressure than a change in fuel injection timing. The focus of this work was to present a novel methodology of using the 3D combustion data from analysis software in the form of a functional mock-up unit (FMU) and showcasing the implementation of a RL algorithm in Python language to interact with the FMU to reduce the NO and soot emissions by suggesting changes to the main injection timing in a pilot–main and pilot–main–post-injection strategy. RL algorithms identified the operating injection strategy, i.e., main injection timing for a pilot–main and pilot–main–post-injection strategy, reducing NO emissions from 38% to 56% and soot emissions from 10% to 90% for a range of fuel injection strategies.
Vaze, Abhijeet, Mehta, Pramod S., Krishnasamy, Anand
Reducing Emissions from Lean-Burn Hydrogen Combustion Engines Using a State-of-the-Art Oxidation Catalyst and a VWTi-Based SCR Catalyst: Potentials and Challenges2024-01-26344/9/2024
Hydrogen (H2) is commonly considered as one of the most promising carbon-free energy carriers allowing for a decarbonization of combustion applications, for instance by retrofitting of conventional diesel internal combustion engines (ICEs). Although modern H2-ICEs emit only comparably low levels of nitrogen oxides (NOx), efficient catalytic converters are mandatory for exhaust gas after-treatment in order to establish near-zero emission applications. In this context, the present study evaluates the performance of a commercial state-of-the-art oxidation catalyst (OC) and of a catalyst for selective catalytic reduction (SCR) that are typically used for emission reduction from diesel exhausts under conditions representative for H2-fueled ICEs, namely oxygen-rich exhausts with high water vapor levels, comparably low temperatures, and potentially considerable levels of unburnt H2. Herein, the OC is supposed to convert H2 slippage, which can occur due to incomplete combustion, and to oxidize NO to NO2, which enables an efficient NOx removal over the SCR catalyst. While the vanadia-based SCR catalyst was barely affected by high water vapor levels, the presence of H2, or hydrothermal aging, H2O inhibited NO to NO2 oxidation over the OC and hydrothermal aging with 20 vol.-% H2O resulted in significant deactivation of the OC. At the cost of producing the inhibitor H2O and the greenhouse gas N2O, the presence of H2 facilitates a fast light-off due to temperature generation. These results underscore the importance of developing suitable catalyst operation strategies that account for efficient pollutant conversion and avoid secondary emissions formation.
Lott, Patrick, Schäfer, Kathrin, Deutschmann, Olaf, Werner, Manuel, Weinmann, Philipp, Zimmermann, Lisa, Toebben, Heike
Particulate filter performance mapping for in-service conformity2024-01-23824/9/2024
The proposed Euro-7 regulations are expected to build on the significant emissions reductions that have already been achieved using advanced Euro VI compliant after treatment systems (ATS). The introduction of in-service conformity (ISC) requirements during Euro VI paved the way for enabling compliance during real-world driving conditions. The diverse range of applications and resulting operating conditions greatly impact ATS design and the ability of the diesel particulate filter (DPF) to maintain performance under the most challenging boundary conditions including cold starts, partial/complete regenerations, and high passive soot burn operation. The current study attempts to map the particle number (PN) filtration performance of different DPF technologies under a variety of in-use cycles developed based on field-data from heavy duty Class-8 / N3 vehicles. Access to such performance maps can allow original equipment manufacturers (OEMs) to select DPF technologies to suit different applications with a better understanding of underlying limitations. The potential inclusion of secondary emissions from diesel exhaust fluid (DEF) injection adds further uncertainty to ATS design including the likelihood of a secondary filter. Different secondary filter technologies were evaluated for DEF PN filtration performance and suitable candidates were identified for SCR systems with reasonable levels of DEF emissions and / or relaxed regulatory limits (>2E11 #/kWh). These results highlight the various product options available to OEMs to meet upcoming Euro-7 HD regulations with suitable safety margins.
Viswanathan, Sandeep, Sadek, Ghadi, Reddy, Vishal, He, Suhao, Alam, Rabeka
Comparison and Feasibility Study of Hexanol/Diesel/Pongamia Biodiesel Blend on Engine Characteristics of a Common Rail Direct Injection Diesel Engine2023-01-51552/23/2024
In this work, the impact of hexanol/diesel/biodiesel blend on engine characteristics of a common rail direct injection (CRDI) diesel engine was studied. Biodiesel is more viscous in nature and higher cetane count, hexanol has a lower viscosity and cetane count. The drawbacks of both biodiesel and hexanol can be overcome by blending both hexanol and biodiesel with diesel fuel in the right proportion. Tests were carried out using a 4-stroke CRDI engine with two cylinders. Biodiesel and 1-hexanol were blended in a ratio of 10% each by volume with diesel and compared with B10D90 and B20D80 blends. It was noted that the addition of hexanol enhances the combustion characteristics of the engine. At 20% load H10B10D80 showed71.34 bar which is highest compared to other fuels in the test. The blends had a positive effect on emissions, there was drastic reduction in NOx was noticed, also HC and CO emission was lower than diesel emissions. The lowest CO, and HC emission is obtained for H10B10D80, which is 66%, 92% lower at 60% load compared to baseline readings. However, the blend had a slight negative effect on performance in contrast to diesel. The higher latent heat of vaporization of hexanol led to low temperature combustion contributing to the lowest NOx emissions. The combination of both hexanol and Pongamia biodiesel with diesel showed an effective reduction in greenhouse gases. Which will also reduce the dependency on fossil fuels. The lower carbon content of 1-hexanol contributes towards carbon neutrality. Overall, the hexanol and biodiesel are sustainable alternatives to the diesel fuel.
Santhosh, K., Shahapur, Saikumar, Kumar, G.N., Ravikumar, K.N., Raghavendra Reddy, N.V.
Understanding the Complexities and Validation of Exhaust System Components for New Emission Requirement with Thermal Load and Multi-Axis Vibration2024-26-03301/16/2024
The new emission requirement norms in India calls for a robust Exhaust and After Treatment System (EATS) in automobiles. Its main purpose is to reduce the emission of harmful pollutants into the environment. EATS have a series of components that cleans the diesel exhaust emitted by the engine prior to releasing it through the tailpipe to the outside air. All the EATS components must undergo stringent testing protocol prior to its implementation in vehicle. During the exhaust treatment process, a very high temperature of about 550°C is produced in the EATS system. Hence, the effect of this higher temperature needs to be considered for validation. Moreover, the components will undergo multi-axial vibration in real road conditions which also need to be simulated during validation. In addition, engine vibrations are directly transmitted through a flex bellow to EATS system. These vibrations need to be captured and simulated in component level testing. In this paper, we detailed on various test conditions for validating EATS assembly and flexbellow inclusive of thermal & multi-axial vibration loading.
Sundarrajan, Manikandan, Narasimman, Obuli Karthikeyan, Nagarajan, Gopikannan, Rajaraman, Manikandan, R, Suresh
Numerical Analyses of AdBlue® Thawing Performance According to EU Norms2024-26-02631/16/2024
Controlling NOx emission demand is getting more severe with Euro 7 legislation. In turn, this brings more focus on SCR (Selective Catalytic Reduction) technology, which uses a eutectic mixture of Urea (32.5%)– Water (67.5%) solution, more popularly known as Diesel Exhaust Fluid (DEF/ AdBlue®). Under extreme winter conditions, AdBlue® freezes as the ambient reaches below the freezing point (-11°C). Due to Legislation requirements (EU), estimating the time required to thaw a desired volume of frozen AdBlue® using forced heating is a matter of interest, leading to the concept of overall Melting/Thawing performance. So far, testing has been the primary method for arriving at a suitable melting mechanism and for designing electrical coils or hot coolant lines, which is expensive. This paper proposes a novel digital method using the 3D CFD tool STAR CCM+ to study the melting behavior of AdBlue®. The method is characterized by capturing phase change using the popular multiphase (VOF) approach and different modes of heat transfer involved in the process. The numerical analyses aided in understanding the influence of ambient (external airflow) conditions around the tank. Estimated AdBlue® temperature distribution inside the tank at various locations was benchmarked with two different test scenarios, viz., Climatic chamber test with external airflow around the tank & without any external airflow. The benchmarked simulation method showed good agreement with the test data. The effect of a completely insulated tank is also explored by modeling the AdBlue® tank under adiabatic condition. Additionally, one of the possible ways to reduce the computation time to estimate the melting performances is also explored. The computation domain was restricted to the region of interest around the sensors and benchmarked with test data. Using this digital method, clear design directions can be arrived at during the initial development stage, eliminating the need for multiple proto builds and validation.
Govindarajan, Vaishali, Varughese, Shibu, Banik, Soumendu, R, Vineeth
Flexible Heating and Heat Retention Technology for Efficient Treatment of Exhaust Gases in Diesel Engines2024-26-01441/16/2024
In the Journey towards Zero Emission and decarbonization, with emerging advancement in technology form current BS6 to near future EURO7 standards of emission, these emission norms are achievable when we amalgamate with an assistive technology of Electrically Heated System for thermal management in Diesel emission control i.e., called CatVap®. With the increasingly stringent limits on vehicle pollutants- including NOx emission levels are fulfilled with Twin Urea Dosing mechanism. These comprehensive lists of advanced technology to converge lowest NOx emissions without increasing CO2 emissions. The Major effort in the existing structure is to accelerate the SCR temperature and enhance the conversion efficiency of NOx in Real Drive Emission during cold start and low load duty cycle. CatVap®system provides sufficient thermal energy to facilitate rapid heating in the course of low load cycles and cold city rides for efficient gas conversion. As they are used to accelerate the light-off temperature for Diesel Oxidation Catalyst (DOC) and Selective Catalytic Reduction (SCR), this system is also highly adaptable for effective regeneration in Diesel Particulate Filter (DPF) and overall, it is an important promoter to accomplish Zero emission Internal Combustion Engines. Albonair is targeting towards optimization of well adapted and cost-effective CatVap technology and dual dosing system to improve BS6 emission standards and to meet BS7/Euro7 regulations. The Development cost and the estimated timeline to encounter BS7 System would not be much challengeable when compared to the implementation of BS6 system.
YS, Ananthkumar, K, Sabareeswaran, M, Jayashree
The Effect of Different Air Path Based ATS Thermal Management Strategy on a Non- EGR Medium Duty Diesel Engine’s Performance and Emissions2024-26-00381/16/2024
The major objective of this paper is to develop thermal management strategy targeting optimum performance of Selective Catalytic Reduction (SCR) catalyst in a Medium Duty Diesel Engine performing in BS6 emission cycles. In the current scenario, the Emissions Norms are becoming more stringent and with the introduction of Real Drive Emission Test (RDE) and WHTC test comprising of both cold and hot phase, there is a need to develop techniques and strategies which are quick to respond in real time to cope with emission limit especially NOx. SCR seems to be suitable solution in reducing NOx in real time. However, there are limitations to SCR operating conditions, the major being the dosing release conditions which defines the gas temperature at which DEF (Diesel Exhaust Fluid) can be injected as DEF injection at lower gas temperatures than dosing release will lead to Urea deposit formation and will significantly hamper the SCR performance. The second factor for optimum SCR operation is to maintain the catalyst temperature where high NOx conversion efficiency is obtained. Dosing release temperature plays an important role to achieve high NOx conversion efficiency, specifically when the aftertreatment system is at ambient temperature. Therefore, thermal management strategy is employed to ensure quick heating of ATS to achieve the Dosing release temperature in the shortest possible time duration. Thermal management involves air path control where actuators are used to alter the exhaust temperature, and also the injection strategies that favors higher exhaust enthalpy at the cost of BSFC. Thermal Management is active until the ATS will reach the certain temperature threshold beyond which the thermal management will be deactivated as prolong activation of thermal management may result in fuel penalty. From the airpath point of view the focus of this paper is towards the utilization of intake throttling, engine brake and variable exhaust flap. Along with the airpath, the impact of combustion retardation is also covered.
Sharma, Ajeet Kumar, Kreuzig, Gerhard, Gupta, Ayush, Goyal, Dinesh, Garg, Varun
A Novel Method for Urea Concentration Deterioration Detection in BSVI Heavy Duty Engine2024-26-01541/16/2024
Diesel Exhaust Fluid (DEF) concentration monitoring is done to detect the concentration at which the emission thresholds are exceeded in BSVI engines [1]. This paper introduces a novel method to model the fault monitoring system with enable conditions designed to detect deterioration in DEF concentration, while reducing misdetection. This eliminates the need for dedicated sensor, reduces complexity, cost, and potential sensor-related failure modes. Traditionally, Diesel Exhaust Fluid quality sensors have been employed to measure the absolute concentration of Diesel Exhaust Fluid in the aqueous solution of urea [2]. This information is used to detect usage of poor quality DEF which results in increase in NOx emission beyond legal limits. The proposed method leverages the strong relationship between catalyst conversion efficiency and Diesel Exhaust Fluid concentration for modelling a fault monitoring system which also takes inputs from various other sensors, to make the system fault tolerant. This innovation contributes to improved emissions control and regulatory compliance in the automotive industry.
Venkat, Harish, Kumar, Gokul Elumalai, Kumar, Kosalaraman, G, Vijayakumar
Diesel Emissions and Their Control, Second EditionR-53312/20/2023
Engineers, applied scientists, students, and individuals working to reduce emissions and advance diesel engine technology will find the second edition of Diesel Emissions and Their Control to be an indispensable reference. Whether readers are at the outset of their learning journey or seeking to deepen their expertise, this comprehensive reference book caters to a wide audience. In this substantial update to the 2006 classic, the authors have expanded the coverage of the latest emission technologies. With the industry evolving rapidly, the book ensures that readers are well-informed about the most recent advances in commercial diesel engines, providing a competitive edge in their respective fields. The second edition has also streamlined the content to focus on the most promising technologies. This book is rooted in the wealth of information available on DieselNet.com, where the "Technology Guide" papers offer in-depth insights. Each chapter includes links to relevant online materials, granting readers access to even more expertise and knowledge. The second edition is organized into six parts, providing a structured journey through every aspect of diesel engines and emissions control: • Part I: A foundational exploration of the diesel engine, combustion, and essential subsystems. • Part II: An in-depth look at emission characterization, health and environmental impacts, testing methods, and global regulations. • Part III: A comprehensive overview of diesel fuels, covering petroleum diesel, alternative fuels, and engine lubricants. • Part IV: An exploration of engine efficiency and emission control technologies, from exhaust gas recirculation to engine control. • Part V: The latest developments in diesel exhaust aftertreatment, encompassing catalyst technologies and particulate filters. • Part VI: A historical journey through the evolution of diesel engine technology, with a focus on heavy-duty engines in the North American market.
Majewski, Addy, Jaaskelainen, Hannu
Development and Testing of End-of-Line (EOL) Tester for Diesel Engine2023-01-50588/25/2023
Decades ago, like the 1990s automobile industry, the off-highway industry was purely recognized as a mechanical entity. In the mechanical system, accuracy and troubleshooting of faults were significant concerns. Additionally, the continuous stringent emission norms by the government call for the adaptation of the aftertreatment and DeNOx led to more complexity and challenges. To meet the government emission regulation and product performance, thorough functionality testing of manufactured units was crucial. For this purpose, EOL/diagnostics testers are developed. Diagnostic protocol CAN establish the connection between ECU and tester due to its robustness and data handling capabilities. This paper aims to develop and test the end-of-line (EOL) tester for off-highway diesel engines. The communication between the tester and ECU will be over UDSonCAN, conforming to standard ISO14229. This tester will cover the synchronization of various components used to assemble the engine and maintain a consumption record. The vital tester implemented the following roles: communication, reading diagnostic trouble code (DTC), data measurement, data logging, and programming data with a friendly and compatible interface. Also, the tool will distinguish nonfunctional units, reduce the rejection rate, and help to maximize productivity by performing appropriate diagnostic checks in case of any faulty situation. The tester will ease the aftertreatment and DeNOx testing.
Khond, Nikita Anil, Gandhi, Naresh, Kakade, Suhas
Laboratory sulfation of an ammonia slip catalyst with a real-world SO 2 concentration2023-01-03804/11/2023
Upcoming, stricter diesel exhaust emissions standards will likely require aftertreatment architectures with multiple diesel exhaust fluid (DEF) introduction locations. Managing NH3 slip with technologies such as an ammonia slip catalyst (ASC) will continue to be critical in these future aftertreatment systems. In this study, we evaluate the impact of SO2 exposure on a state-of-the-art commercially available ASC. SO2 is co-fed at 0.5 or 3 ppmv to either approximate or accelerate a real-world exhaust SO2 impact. ASC performance during sulfur co-feeding is measured under a wide variety of simulated real-world conditions. Results indicate that the loss of NO conversion during SCR is dependent on the cumulative SO2 exposure, regardless of the inlet SO2 concentration. Meanwhile, N2O formation under SCR conditions is nonlinearly affected by SO2 exposure, with formation increasing during 0.5 ppmv SO2 exposure but decreasing in the presence of 3 ppmv SO2. TPO experiments reveal the formation of ammonium sulfate species, but only after prolonged SO2 exposure at 0.5ppmv or accelerated SO2 exposure at 3 ppmv. Reactivation at 550°C is sufficient to recover ASC reactivity following multiple SO2 exposure tests in all cases. These findings are especially relevant for the development of diesel exhaust aftertreatment accelerated aging protocols.
Ottinger, Nathan, Xi, Yuanzhou, Kiani, Daniyal, Liu, Z. Gerald
A Multi-Function, Heated Mixer for Rapid Heat-up, Low-Temperature Ammonia Demand, Deposit Prevention and to Meet Ultra-Low NOx Regulations2023-01-03564/11/2023
Selective Catalytic Reduction (SCR) operation depends strongly on both heat and ammonia availability (stored or incoming). These requirements make high efficiency SCR challenging in lower temperature cycles where SCR is relatively cold, and Diesel Exhaust Fluid (DEF) injection is largely absent due to deposit risks. Examples include low temperature cycles such as low-idling, stop-and-go or low-load cycles such as city driving or local delivery cycles. An Electrically Heated Mixer/ EHM™ is utilized to address these challenges in a single component. EHM simultaneously provides heat for rapid SCR heat-up during the cold phase or in other low-temperature operations, steady or transient. Second, its heating mechanism makes deposit risks nearly non-existent. Third, EHM enables DEF injection at 130 °C, markedly enhancing the low temperature SCR impact. It is shown that these capabilities collectively make EHM a promising pathway for meeting ultra-stringent NOx targets including California 2027 (0.02 gr/hp.hr). Via rapidly heating the SCR catalyst during cold-start, EHM enables substantially lowering the cold-phase NOx. For instance, it is shown this lowers the cold FTP and cold WHTC NOx emission by 2 – 2.5 fold and in Low-Load Cycle by 22-fold. EHM also allows DEF injection in low exhaust temperatures such as in 70 - 80 °C, for instance for rapidly filling the SCR catalyst with ammonia, if needed. Unlike adding other exhaust flow heating devices where an additional component is ultimately integrated in the aftertreatment architecture, EHM is a mixer, already present in emission control systems. These flexibilities, along with its lower cost and ease in fitting, make EHM an enabling pathway for Diesel emission control systems meeting very low NOx regulations.
Masoudi, Mansour, Poliakov, Nick, Noorfeshan, Sahm
Evaluation of the Effectiveness of Diesel Particulate Filter Cleaning Methods and their Effect on Fuel Consumption2023-01-03764/11/2023
The negative effects of long-term exposure to soot and particulate matter emissions from diesel exhaust on the human health have been widely acknowledged due to the harmful substances that exhaust gas contains. Regulators have established strict programs to determine the performance and reliability of emissions after-treatment systems and devices. Tests were conducted to evaluate the efficacy of three diesel particulate filter (DPF) cleaning methods: 1) thermal and pneumatic cleaning, 2) ultrasonic cleaning, and 3) aqueous cleaning methods. A novel non-destructive method to quantify soot and ash deposits in the filters was developed, validated and used to determine the effectiveness of the identified cleaning methods. Given the number of different cleaning methods available, testing against a set of standard parameters provided accurate comparative results. Test results showed at least satisfactory ratings for all cleaning systems that were evaluated, while two systems stood out with very good ratings, with up to 96% of deposits removed by one cleaning system. Fuel consumption tests based on SAE J1321 and TMC RP 1102A Fuel Consumption Test Procedure – Type II were also performed to determine the effect of diesel particulate filter cleaning methods on fuel consumption. The tests were conducted on a high-speed test track at a constant speed of 105 km/h (65 mph). Test results showed that excluding the fuel consumed during passive regeneration, the level of obstruction of the diesel particulate filter showed little impact on fuel consumption. Results comparing the fuel consumption of a cleaned DPF versus that of a used DPF ranged from 0.65% to 1.43%.
Bonsi, Adime Kofi, Surcel, Marius-Dorin, Szathmary, Gabor
The Effect of Exhaust Emission Conditions and Coolant Temperature on the Composition of Exhaust Gas Recirculation Cooler Deposits2023-01-04384/11/2023
Exhaust Gas Recirculation (EGR) coolers are widely used on diesel engines to reduce in-cylinder NOx formation. A common problem is the accumulation of a fouling layer inside the heat exchanger, mainly due to thermophoresis that leads to deposition of particulate matter (PM), and condensation of hydrocarbons (HC) from the diesel exhaust. From a recent investigation of deposits from field samples of EGR coolers, it was confirmed that the densities of their deposits were much higher than reported in previous studies. In this study, the experiments were conducted in order to verify hypotheses about deposit growth, especially densification. An experimental set up which included a custom-made shell and tube type heat exchanger with six surrogate tubes was designed to control flow rate independently, and was installed on a 1.9 L L-4 common rail turbo diesel engine. The test cycle and conditions were higher PM/ lower HC with 75°C coolant temperature for 1.5h, then lower PM/ higher HC with 75°C or 35°C coolant temperature for 0.5h, which was repeated 3 times. Deposits from a tube were collected every cycle for a total of 6h. In the analysis, the deposit surface was observed with a scanning electron microscope, thickness was measured by an optical microscope, and the volatile content was analyzed by a thermogravimetric analyzer (TGA). The results of this study showed that including the cold coolant condition cycle could keep higher heat exchanger effectiveness compared to the hot coolant condition, even though total deposit weight was almost the same. In addition, growth of the deposit thickness was not seen with the cold coolant condition, which was confirmed via the measurements of deposit densification. These data indicate that there is possibly a correlation between repeated hydration of the deposit by condensed water and drying.
Tomuro, Minato, Bhadra, Kaustav, Hebert, Jason, Boehman, Andre
PERFORMANCE SPECIFICATION FOR AUTOMOTIVE WIRE HARNESS RETAINER CLIPSUSCAR44-2 (Current)3/23/2023
This specification describes a method and acceptance criteria for testing automotive wire harness retainer clips. Retainer clips are plastic parts that hold a wire harness or electrical connector in a specific position. Typical plastic retainers work by having a set of “branches” that can be inserted into a hole sized to be easy to install but provide acceptable retention. This specification tests retainer clips for mechanical retention when exposed to the mechanical and environmental stresses typically found in automotive applications over a 15-year service life. This specification has several test options to allow the test to match to the expected service conditions. The variability of applications typically arises from different ambient temperatures near the clip, different proximity to automotive fluids, different exposure to standing water or water spray, and different thicknesses of the holes that the clip is inserted into. Clips are typically inserted into sheet or rolled metal from 0.6 to 8 mm thick, so this specification focuses on that range. Outside of this range requires a custom test. The procedures described in this document have been evaluated for the design types shown in Table 2. Use of USCAR-44 for other than a design shown in Table 2 may or may not produce acceptable test correlation to actual experience, but USCAR has not reviewed any data. USCAR-44 can be used at all phases of development, production, and field analysis since it is a performance test and not a process validation or quality assessment. No retainer may be represented as having met USCAR/EWCAP specifications unless conformance to all applicable requirements of this specification have been verified and documented. All required verification and documentation must be provided by the supplier of the part. If testing is performed by another source, it does not relieve the primary supplier of responsibility for documentation (DVP&R) of all test results and for verification that all samples tested met all applicable acceptance criteria.
USCAR
Application of Model-Based Controller on a Heavy-Duty Dual Selective Catalytic Reduction Aftertreatment03-16-05-00403/8/2023
Commercial vehicles require advanced engine and aftertreatment (AT) systems to meet upcoming nitrogen oxides (NOx) and carbon dioxide (CO2) regulations. This article focuses on the development and calibration of a model-based controller (MBC) for an advanced diesel AT system. The MBC was first applied to a standard AT system including a diesel particulate filter (DPF) and selective catalytic reduction (SCR) catalyst. Next, a light-off SCR (LO-SCR) was added upstream of the standard AT system. The MBC was optimized for both catalysts for a production engine where the diesel exhaust fluid (DEF) was unheated for both SCRs. This research shows that the tailpipe (TP) NOx could be reduced by using MBC on both catalysts. The net result was increased NOx conversion efficiency by one percentage point on both the LO-SCR and the primary SCR. The CO2 emissions were slightly reduced, but this effect was not significant. Finally, the MBC was used with a final setup representative of future AT systems which included standard insulation on the catalysts and optimal DEF dosing controls. This final configuration resulted in an improved NOx and CO2 such that the composite Federal Test Procedure (FTP) NOx was 0.060 g/hp-hr and the composite FTP CO2 was 508.5 g/hp-hr. The article details this cycle along with the low-load cycle (LLC) and beverage cycle. More technologies are required to meet the future California Air Resources Board (CARB) 2027 standard, which will be shown in future work.
Meruva, Prathik, Matheaus, Andrew, Zavala, Bryan, Sharp, Christopher A., McCarthy Jr., James E.
Detailed Compositional Comparison of Hydrogenated Vegetable Oil with Several Diesel Fuels and Their Effects on Engine-Out Emissions04-16-03-001512/8/2022
The Coordinating Research Council (CRC) is actively involved in developing and applying advanced analytical techniques to the chemical characterization of transportation fuels. This article complements a 2017 CRC project to quantify and compare the effects of a commercially available renewable diesel fuel (hydrotreated vegetable oil [HVO]) and an ultralow sulfur diesel (ULSD) fuel on engine-out gaseous and particulate matter (PM) emissions from a light-duty vehicle. Results showed that the combustion of HVO fuel had an advantage over ULSD in terms of lowering engine-out emissions (THC, CO, NOx, etc.). Furthermore, this advantage is strongly related to the fuel composition. This article summarizes the results of advanced and comprehensive analytical tests on the same ULSD and HVO fuels and attempts to connect some of the engine-out emissions results to fuel composition and specific chemical structures. A variety of test methods, generally unavailable in combination, were employed, such as one-dimensional (1D) and two-dimensional (2D) gas chromatography (GC), nuclear magnetic resonance spectroscopy (NMR), and high-pressure solid-liquid phase transition experiments. In summary, the ULSD sample was found to have representation across the expected set of hydrocarbon classes typical for the sample type. Interestingly, a high content of cycloparaffins (>50 wt%) and a very low content of diaromatics (~2 wt%) were present. While not without precedent, these are higher and lower, respectively, than typically found for commercial ULSD compositions. In contrast, HVO was found to consist of only two hydrocarbon classes: n-paraffins (~10 wt%) and iso-paraffins (~90 wt%), both predominantly in a narrow carbon atom number range (i.e., C14–C18). HVO engine-out emissions results for the LA-92 and steady-state testing can be tracked to the narrow carbon atom number range of the n-paraffins and iso-paraffins, which result in a high cetane number fuel having a narrow distillation range. Previously, the low-temperature operability of HVO has been a concern, but that appears not be the case for this particular HVO. HVO and ULSD were evaluated at pressures up to ~275 MPa and found to have comparable solid-liquid equilibria despite significant compositional differences.
Bays, J. Timothy, Gieleciak, Rafal, Viola, Michael B., Lewis, Russ P., Cort, John R., Campbell, Kristen B., Coffey, Gregory W., Linehan, John C., Kusinski, Matthew
Heavy-Duty Diesel Truck In-Use NO x Emissions Evaluation Using On-Board Sensors2022-01-509811/21/2022
Governments and regulatory agencies in North America are evaluating the nitrogen oxides (NOx) emissions of heavy-duty on-road vehicles to effectively regulate these emissions in order to improve public health and meet air quality requirements. This paper provides results from real-world Class 8 tractor-trailer truck activity and emissions data gathering conducted in the Northeast and Mid-Atlantic United States. Unlike some other areas of the United States (US), there is little available data on in-use operation and emissions performance from heavy-duty trucks in this region where temperatures can be consistently cold in winter. The purposes of this study are to add to the literature on real-world truck operation and emissions in the Northeast and Mid-Atlantic regions; to analyze the captured emissions data using recently established calculation methods implemented by the California Air Resources Board (CARB), which have not yet been applied to data from this region; and to assist air quality regulators in identifying priorities for new heavy-duty engine and vehicle emission standards and test procedures. The Northeast States for Coordinated Air Use Management (NESCAUM) conducted this project jointly with Environment and Climate Change Canada (ECCC). Given the proximity of the truck routes evaluated in this project to the Eastern Canadian provinces, the information is of interest to Canadian regulators as well. The results of this data logging and analysis showed that the CARB’s three-bin moving average window (MAW) and sum-over-sum NOx emissions calculations can be successfully applied to in-use truck data sets. However, the use of the on-board vehicle NOx sensors for data logging limited the amount of time that data were able to be captured at low loads. The active percentage time of sensors by truck was between 43% and 80% in low-load conditions (69% over all trucks). Therefore, low-load data was “backfilled” with estimated emissions values in order to compensate for the time the sensors were inactive. Backfilled data showed that a range of 21% to 67% of the mass of NOx emitted by individual trucks occurred in idle and low-load conditions combined, whereas the original data showed values between 10% and 43%. Median daily backfilled sum-over-sum NOx emissions results by truck specimen ranged from 0.32 g/bhp-hr to 0.75 g/bhp-hr in low-load conditions and from 0.02 g/bhp-hr to 0.16 g/bhp-hr in high-load conditions. As part of the study, data on over 150 vehicle and engine parameters during 100 days of truck operation were collected. This data can be used by regulators and researchers to evaluate truck emissions and operations in the region.
Humphries, Kieran, Cooper, Coralie, Ahmadi, Mahdi
Effect of Fuel Reactivity on Engine Performance and Exhaust Gas Emissions in a Diesel Engine04-16-02-001211/10/2022
Using a compression engine with dual fuel is the most promising technology to control emissions and for fuel economy, to meet the upcoming legislative norms. This experimental study was conducted to understand the effect of fuel reactivity on engine performance and emission in a compression ignition (CI) engine. The effect of injection timing, gasoline ratio, and exhaust gas recirculation (EGR) rate on emission is compared to the conventional diesel engine. In this study, high-octane fuel (gasoline) is injected manifold the intake of a diesel engine (high-reactivity fuel) to primarily investigate the effects of balance between fuels having low and high reactivity. Fuel reactivity is optimized on different load and speed conditions by varying the diesel and gasoline quantity. Experimental results indicate that dual fuel helps to avoid nitrogen oxides (NOx) and soot trade-off, mitigating both to near-zero values. The engine was tested at a constant speed of 1520 rpm and showed a reduction in NOx and soot emissions with an increase in the gasoline content ratio. The fuel consumption was reduced to 249 g/kWhr from 254 g/kWhr of the diesel engine when operated with a gasoline ratio of 70%. Simultaneously, both NOx and soot emissions were reduced to about 0.42 g/kWhr and 0.06 g/kWhr, respectively. The best operating zone with dual fuel showed a significant reduction of NOx and soot emission but high HC and CO with the use of EGR and gasoline variation in different loads and speeds. The enhancement in thermal efficiency and lowering of heat and exhaust losses were secured using low-reactivity fuel.
Barman, Jyotirmoy, Deshmukh, Devendra
A New Electrically Heated Mixer (EHM) for Efficient SCR of NOx in Low Load Cycles2022-01-11539/13/2022
Low temperature Diesel exhaust operations such as during low-load cycles are some of the most difficult conditions for SCR of NOx. This, along with newer regulations targeting substantial reduction of the tailpipe NOx such as California-2024/2027 NOx regulations, adds to challenges of high efficiency SCR of NOx in low temperature operations. A novel design, low-cost, low-energy Electrically Heated Mixer (EHM™), energized via the 12, 24 or 48 V vehicle electrical system, is used to accelerate formation of reductants (ammonia, isocyanic acid) in low temperature exhaust (low load cycles), so to enable high efficiency SCR of NOx in most challenging SCR conditions, while also mitigating urea deposit formation. EHM™ is also used to heat the cooler exhaust flow during engine cold-start. It easily fits common exhaust configurations and can be utilized on light, medium or heavy duty Diesel aftertreatment systems, on- or non-road or in stationary systems.
Masoudi, Mansour, Poliakov, Nick, Noorfeshan, Sahm
From emissions tech to EV electronics22AUTP09_039/1/2022
Eberspaecher's Electronics unit is enabling big growth in EV and AV business. A recent visit to Eberspaecher's North American engineering and manufacturing complex reveals how a global Tier-1 rooted in combustion-engine technology is profitably navigating the transition to the electrified future. In the Brighton, Michigan, plant, which produces 40% of U.S. Class-8 diesel exhaust systems, catalyst bricks are being canned and prepared for shipment to OEMs. Meantime in the facility's engineering offices, work is progressing on next-generation heating systems for passenger and commercial EVs, power electronics, automated-driving systems, and high-voltage switching solutions. Best known for 90 years as an exhaust-systems and climate-controls supplier, the Germany-based company now is a parallel force in electric power switching and distribution. Since establishing its Electronics business unit in the early 2000s, Eberspaecher has produced 30 million electronic control modules, more than 17 million high-performance switches and six million DC/DC converters, among other power-net components.
Brooke, Lindsey
The DAAAC Protocol: A Procedure for Developing Accelerated Aging Cycles for Diesel Aftertreatment2022-01-10178/30/2022
Accelerated aging of automotive gasoline emissions catalysts has been performed on bench engines for decades. The EPA regulations include an accelerated aging cycle called the Standard Bench Cycle (SBC) that is modeled on the RAT-A cycle developed by GM Corp. and published in 1988. However, this cycle cannot be used for diesel aftertreatment components because it is based on stoichiometric operation, whereas diesel engines typically operate under excess air (lean) conditions. The need for accelerated aging cycles for diesel emissions systems can be illustrated by considering that the full useful life (FUL) requirement in the United States for an on-highway truck is 435,000 miles, and an off-road application may be 8,000 hours. With the recent CARB Omibus legislation, the durability duration will be increasing for on-road applications by as much as 80 percent in the next decade. Additionally, regulators have implemented much more stringent durability demonstration requirements which include generating and evaluating FUL equivalently aged aftertreatment components for certification. Aging under normal operating conditions is time-consuming and expensive. This need was recognized, and the Diesel Aftertreatment Accelerated Aging Cycles (DAAAC) Protocol was developed to provide accelerated aging cycles for diesel emissions system applications. The DAAAC Protocol is a diesel aftertreatment accelerated aging procedure that results in catalytic system deterioration similar to that observed in field-aged components. This protocol includes primary aging deactivation mechanisms observed on diesel engine aftertreatment systems such as hydrothermal, chemical exposure, and deposit deposition. The procedures that were developed aimed to shorten durability testing times dramatically, with a reduction in durability testing time goal of ≥ 90 percent. This paper describes the DAAAC Protocol that is being considered for emissions system certification use in the US.
Eakle, Scott, Zavala, Bryan, Sharp, Christopher
Low-Temperature NO x Reduction by H 2 in Diesel Engine Exhaust2022-01-05383/29/2022
For the NOx removal from diesel exhaust, the selective catalytic reduction (SCR) and lean NOx traps are established technologies. However, these procedures lack efficiency below 200 °C, which is of importance for city driving and cold start phases. Thus, the present paper deals with the development of a novel low-temperature deNOx strategy implying the catalytic NOx reduction by hydrogen. For the investigations, a highly active H2-deNOx catalyst, originally engineered for lean H2 combustion engines, was employed. This Pt-based catalyst reached peak NOx conversion of 95 % in synthetic diesel exhaust with N2 selectivities up to 80 %. Additionally, driving cycle tests on a diesel engine test bench were also performed to evaluate the H2-deNOx performance under practical conditions. For this purpose, a diesel oxidation catalyst, a diesel particulate filter and a H2 injection nozzle with mixing unit were placed upstream to the full size H2-deNOx catalyst. As a result, the Worldwide harmonized Light vehicles Test Cycle (WLTC), urban cycle segment of the Common Artemis Driving Cycle (CADC UC) and Transport for London Urban Inter Peak (TfL UIP) driving cycle revealed NOx conversions up to 90 % at temperatures as low as 80 °C. However, outside the low-temperature region, H2-deNOx activity dropped significantly evidencing the need for an additional underfloor SCR system. Moreover, slight N2O formation was observed in the engine tests making further catalyst development necessary, since N2O is considered a critical component due to its global warming potential. Additionally, the H2 demand for low-temperature deNOx in diesel passenger cars was estimated and a novel on-board H2 production strategy based on DEF electrolysis was developed. This method provided both H2 as well as gaseous NH3. Subsequent simulations of H2 production demonstrate small size factors (≤ 525 cm3) and rather low energy consumption of the H2 supply unit, e.g. 0.25 kWh for the TfL UIP driving cycle.
Esser, Enno, Kureti, Sven, Heckemüller, Lukas, Todt, Arne, Eilts, Peter, Morawietz, Tobias, Friedrich, Andreas, Waiblinger, Wendelin, Hosseiny, Schwan, Bunar, Frank
Meeting Future NO X Emissions Over Various Cycles Using a Fuel Burner and Conventional Aftertreatment System2022-01-05393/29/2022
The commercial vehicle industry continues to move in the direction of improving brake thermal efficiency while meeting more stringent diesel engine emission requirements. This study focused on demonstrating future emissions by using an exhaust burner upstream of a conventional aftertreatment system. This work highlights system results over the low load cycle (LLC) and many other pertinent cycles (Beverage Cycle, and Stay Hot Cycle, New York Bus Cycle). These efforts complement previous works showing system performance over the Heavy-Duty FTP and World Harmonized Transient Cycle (WHTC). The exhaust burner is used to raise and maintain the Selective Catalytic Reduction (SCR) catalyst at its optimal temperature over these cycles for efficient NOX reduction. This work showed that tailpipe NOX is significantly improved over these cycles with the exhaust burner. In certain cases, the improvements resulted in tailpipe NOX values well below the adopted 2027 LLC NOX standard of 0.05 g/hp-hr, providing significant margin. In fact, near zero NOX was measured on some of these cycles, which goes beyond future regulation requirements. However, burner operation on the tested cycles also resulted in a CO2 increase, indicating that a different burner calibration strategy, or possibly an additional technology, will be needed to achieve lower CO2 emissions.
McCarthy, Jr., James, Matheaus, Andrew, Zavala, Bryan, Sharp, Christopher, Harris, Thomas
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