Browse Topic: Exhaust pipes

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Experimental Investigation on Unburned Methanol and Formaldehyde Emissions from a Direct-Injection Diesel / Methanol Dual-Fuel Engine2026-99-16467/24/2026
For large-bore marine methanol / diesel dual-fuel engines, this study investigates the formation characteristics of unregulated emissions through experimental methods and explores the mechanisms by which engine load and injection timing influence the emissions of unburned methanol and formaldehyde. The study was carried out on a supercharged intercooled inline six-cylinder engine, and Fourier Transform Infrared Spectroscopy (FTIR) was used to monitor the exhaust composition in real time. The study shows that methanol released in the exhaust is due to the incomplete combustion of the methanol fuel. In the combustion process of methanol fuel, formaldehyde mainly arises from two pathways, the first of which is the partial oxidation of methanol inside the cylinder; secondly, the unburned methanol in the exhaust gas oxidizes in the exhaust pipe to generate formaldehyde. As the load increased from 25% to 100%, the unburned methanol emissions decreased by 29%, and formaldehyde emissions decreased by 71%. This is mainly attributed to the enhanced oxidation reaction and reduced wall crevice effect due to the increased combustion temperature. Methanol injection timing optimization was effective in controlling unregulated emissions, with methanol emissions lower at -7° CA ATDC and formaldehyde emissions reaching larger values under this condition. Delaying the diesel injection to -16°CA ATDC led to a 38% increase in unburned methanol emissions, caused by fuel spray interactions and longer stagnation, whereas formaldehyde emissions showed minimal change.
Jiang, Yuqi, Li, Hongmei, Zhang, Wenzheng, Li, Xiao, Zheng, Liang, Meng, Yangqian, Gu, Xianan, Hua, Hanqing
Development of a Variable Interface Finite Volume Method for Simulating One- and Three-Dimensional Unsteady Gas Flow and Performances of Underwater Marine Diesel Engines03-19-03-00125/6/2026
Diesel engines used for the main power supplier of submarine normally run in high back pressure and low intake pressure, causing unstable performances. Furthermore, when a submarine runs under the sea the exhaust pipe of the diesel engine is under the seawater. Once the lowest pressure in the exhaust pipe is not sufficient to push all the water out, the water will flow into the exhaust pipe and damage the diesel engine. Modeling can provide a useful guide for designing diesel engines, intake and exhaust pipes, and turbocharging systems to avoid water flowing into diesel engine. However, existing simulation methods cannot well simulate the exhaust system of an underwater diesel engine, in which the interface between the liquid water and the exhaust gas is variable. To overcome the drawbacks of existing simulation methods in handling the variable interface between the two phases, a variable interface finite volume method (FVM) is proposed, and a corresponding model is developed in this work. This is the major contribution of this work. A detailed model description and numerical treatment of governing equations are given. The new model is validated using the experiment conducted in this work on the procedure of gas pushing water in a pipe. The validation results show that the variable interface FVM is effective and reliable. Due to the complexity of the exhaust gas flow at the tailpipe, three-dimensional (3D) flow at the exit of exhaust pipe under different exhaust gas speeds is studied. Results show that, when the exhaust gas speed is below 20 m/s, after the bubble leaves the exit, a part of seawater will flow into the exhaust pipe and flow down along the pipe wall under gravity. With the increase in speed, this phenomenon disappears. Using the newly developed one-dimensional (1D) and 3D model, the 16V-MTU396SE84 underwater diesel engine’s performance was simulated under different back pressures. Also, the effect of silencer’s volume on the stability of diesel engine’s exhaust system was studied. Simulation results show that, with the increase in exhaust back pressure, the excess air factor becomes smaller, combustion turns worse, combustion pressure and maximum in-cylinder pressure become lower, the combustion temperature, maximum temperature, and brake specific fuel consumption go up. In addition, silencer’s volume is very important to the stability of engine performance. The bigger the silencer, the more stable the exhaust system. The flow in the 16V-MTU396SE84 diesel engine’s exhaust pipe under the seawater was also calculated. Simulation results are consistent with engine tests showing that when the engine runs under full load the exhaust gas pressure and the pushing water speed in the exhaust pipe are high, whereas in the part load, the exhaust gas pressure and the water speed become a little lower. The correct results of these simulated performances of underwater marine diesel engines indicate that the models newly developed in this work are reliable.
Guo, Dongshao, Zhang, Licheng, Yang, Shiyou, Sun, Yong, Abidin, Zainal, Lin, Shujun
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
Development of a Zeolite-Based (HC/NOx Trap Type) Cold-Start Catalyst (CSC) for Meeting Tier4/LEV IV Tailpipe Emission Standards, Part IV2026-01-03644/7/2026
This paper is a follow-up study to three preceding reports [1,2,3] that focus on the development of a β-zeolite-based hydrocarbon/nitrogen oxide (HC/NOₓ) trap-type cold-start catalyst (CSC) — a cost-efficient technical strategy for meeting the increasingly stringent vehicle tailpipe emission standards for automotive exhaust systems, including Tier 4 and LEV IV, which are to be enforced in the near future. A core challenge in meeting Tier 4 and LEV IV exhaust emission standards lies in the fact that both the SC03 and US06 test cycles commence from ambient (cold) temperatures, as opposed to the elevated (hot) starting temperatures mandated for the preceding Tier 3 and LEV III standards. In the present study, a hybrid electric vehicle (HEV) fitted with two distinct Tier 3-certified exhaust aftertreatment systems—one officially certified to Bin 30 standards and the other a Bin 20-equivalent system (non-officially certified)—was subjected to testing under the cold SC03, cold US06, hot SC03, and hot US06 test cycles for the purpose of comparative analysis. To meet the Tier 4/LEV IV Bin 30 engineering target of 13.13 mg/mile for combined NOₓ+NMHC tailpipe emissions, the HEV with the Tier 3 Bin 30 system required an approximate 64% reduction in tailpipe emissions during cold SC03 tests, while the HEV with the Tier 3 Bin 20 system needed a 52% reduction. For cold US06 tests, these two HEVs required emission reductions of 50% and 38%, respectively, to achieve the same target. The higher tailpipe emissions observed in cold tests (relative to hot tests of the same cycles) are attributed to elevated cold-start emissions. The CSCs developed in this work were applied to modify the Tier 3 Bin 20 aftertreatment system, and vehicle tests were conducted with the CSC-modified systems under both cold SC03 and cold US06 cycles. Notably, the CSCs effectively reduced cold-start tailpipe emissions (NOₓ+NMHC) in both test cycles, enabling the HEV to meet the Tier 4/LEV IV Bin 30 engineering target of 13.13 mg/mile for NOₓ+NMHC tailpipe emissions. Detailed emission results, along with the effects of zeolite loading and Pd loading on CSC performance, were also investigated and are discussed in this manuscript.
Xu, Lifeng, Wei, Hong, Zhao, Pengfei, Ma, Ruibo, Wang, Lin, Qian, Wangmu, Qian, Menghan
NVH Refinement on the Agriculture Tractor using Coupled Test and Simulation Approach2026-26-03161/16/2026
The Indian farmers choice of agriculture tractor brand is driven by the ease of operation and fuel efficiency. However, the customer preference for operator comfort is driving many tractor OEMs for improvement in noise and vibration at the operator location. Also, the compliance to CMVR regulation for noise at operator ear location and vibration at operator touch point location are mandatory for all the tractors in India. NVH refinement development of the tractor plays a critical role in achieving the regulated noise level and improved tactile vibration In presented work, the airborne sources such as exhaust tail pipe, intake snorkel and cooling fan are quantified by at tractor level through elimination method. The detailed engine level testing in engine noise test cell (hemi anechoic chamber) is carried out to estimate the contribution of engine components to overall noise. The outcome of Noise source identification (NSI) has revealed silencer, timing gear cover and oil sump to be highest ranked sources in descending order. The silencer design using FEM/BEM tools is carried out which had yielded noise reduction up to 4 dB at Full load. Also, operational deflection shape of complete chassis system is carried out to identify the structural weakness. Improvement in engine primary balancing and structural changes has yielded up to 60% reduction in operator touch point vibration.
Gaikwad, Atul Annasaheb, Harishchandra Walke, Nagesh, Yadav, Prasad S, Bankar, Harshal
Development of above 500 kW Diesel Engine & After Treatment System to Meet CPCB-IV+ Emission Norms2026-26-02341/16/2026
The CPCB-IV+ emission compliance for genset application is applicable with effect from 1st July 2023 as per as per GSR 804(E). The CPCB-II to CPCB-IV+ changeover in very stringent in emission front by almost 90 % emission reduction. It’s a significant advancement in environmentally sustainable powertrain technology. To meet the CPCB-IV+ Emission, combustion development & ATS technology plays an important role. First is the base engine need to optimize enough with combustion & associated parts. Second is the after treatment system which will carry the battle further to the engine emission with minimum margin of 10 % engineering target. This paper present the systematic approach followed to meet CPCB-IV+ emission norms for upgradation of 21 litre TCIC engine for the power range (56 < P ≤ 560). Here the challenge to avoid major changes in the existing CPCB-II FIE recipe & meet the CPCB-IV+ emission with ECU calibration & ATS system calibration with its potential. Here interesting parts unique communication architecture built with genset controller in leading role due to time line constraints. The engine integrates with advanced combustion strategies, improved fuel injections systems, and robust after treatment technology including DOC, DPF & SCR system to significantly reduce NOX, PM, HC & CO Emission. Phase-I (Base engine Calibration): - Baseline engine optimization with existing CPCB-II recipe & ECU calibration feature. Here we have used the 1600 bar rail pressure potential along with optimized fuel timing. The pilot & post injection strategy plays vital role to meet the targeted base engine emission. Phase-II (ATS system selection & its calibration): - To meet the CPCB-IV+ emission norms, stringent limits of NOX, PM introduces in India for genset application. For achieving this a highly optimized after treatment system (ATS) comprising DOC, DPF, SCR, and ASC is essential however our strict target is to avoid the DPF. These strategies collectively help to meet the CPCB-IV+ emission targets with optimum engine performance & fuel economy with potential of ATS architecture and a structured calibration methodology. The DOC enables rapid HC/CO oxidation, while the SCR system, controlled via open-loop urea dosing, achieves >95% NOx conversion. The ASC prevents ammonia slip beyond 10 ppm, ensuring exhaust pipe compliance. This project completed within very low stipulated time month effectively. Phase-III (OBD): - The OBD part of CPCB-IV+ contains the following Check on Torque Reduction & Shutdown Strategy Components wise diagnostic calibration on first proto Report on final diagnostic calibration Phase-IV (Engine Consistency & TA Certification):- Emission consistency trial.
Rane, Vikas, Jagtap, Shailesh, Gothekar, Sanjeev, Pawar, Narendra V, Khedkar, Prasad, Kagade, Samadhan, Kendre, Mahadev, G Bhat, Prasanna, Thipse, S
Multi-Objective Design Optimization and Pugh Matrix Analysis to Develop Exhaust Tail Pipe Mounting for EU6 Heavy Trucks2025-28-029311/6/2025
The key performance evaluation criteria for any automotive exhaust system are pass-by noise (PBN), exhaust backpressure, durability and reliability, exhaust brake performance, aesthetics (if visible from outside the chassis), cost, weight and safety. Also, with changes in emission norms, emission from Exhaust Aftertreatment Systems (EATS) is one of the crucial parameters while designing the exhaust system. This paper covers a critical problem faced during the Beta Proto Build and Testing phase of exhaust tail pipe assembly. The exhaust tail pipe assembly had loose fitting issues, which can cause problems during the functioning of the truck. Parameters like material of the pipe, length of strap, tightening torque and tolerance of the pipe diameter were considered to resolve the fitment issue. The resolution is done with the help of Design of Experiments (DoE) and Pugh Matrix Analysis based on QDCFSS (Quality, Design, Cost, Feature, Safety and Sustainability). Design for Assembly (DFA) is a critical event, especially at Beta Proto Build and the pre-launch production phase. It has the dependency with design, parts (piece to piece variations- like dimension, material property), method shop floor facilities / resources (workstation – tools / machines), method/practices (variations – plant to plant / location to location) and workforces (training and physical states - like height). In the subject case, torque loosening / variations and difficulty in assembly have been reported from different plants / proto shops globally for the mounting of the exhaust tail pipe of EU6 heavy Trucks. In this context, Multi-Objective Optimization (MOO) is done with reference to DoE and Pugh Matrix evaluation to resolve the validation phase (testing) blocker problem of EU6 global trucks. Also, Quality Tools are used to do Root Cause Analysis (RCA), find Interim Corrective Action (ICA), and come up with different inputs for DoE. The primary objective of this research is to investigate and optimize the factors involved in tail pipe mounting schemes, which consist of tail pipe (GD&T and material), mounting clamp, torquing, and orientation preference. In material selection, Sustainability which is focused on SOC (substance of concern), CO2 reduction and R-Cycle framework, is equally important in decision making. This work indicates that the DoE technique, along with QDCFSS assessment, is very effective in optimizing multiple factors and resolving the problem identified by the proto build and testing team and ensuring follow the project milestone and business continuity.
P, Balu Mukesh, Rokade, Aditya, Biswas, Sanjoy
Application of MAN Loop Scavenging in a 125 cm 3 Two-Stroke Racing Engine2025-32-002911/3/2025
The use of MAN-type loop scavenging port arrangements in a 125 cc two-stroke racing engine is being investigated. These make it possible to provide larger cross-sections for the transfer ports, but at the expense of the exhaust port cross-section. The investigation is carried out using 1D calculations with GT-Suite. It is shown that significantly higher maximum outputs are possible in this way. However, this requires large exhaust widths, as otherwise the exhaust port is too small and the advantage of the larger transfer cross-section is overcompensated. Mixed forms between the original MAN loop scavenging and Schnürle loop scavenging can represent a good compromise. To improve the power characteristic vs. speed, which is influenced negatively by the higher maximum outputs, optimizations of port heights and exhaust pipe dimensions are carried out. A configuration with the same maximum output as the basis but a wider power band is also shown. One open point is the quality of the scavenging. Results from the literature suggest that similarly good results are possible with MAN-type loop scavenging as with the Schnürle scavenging of the base engine. However, further investigations are required here.
Eilts, Peter
Development of Supercharged Direct-Injection Two Stroke Engine with Intake and Exhaust Valve for Series Hybrid (2nd Report)- To Realize Lean Burn -2025-32-002311/3/2025
The two-stroke engine, known for its small displacement and high performance, is space-efficient when installed in a vehicle. As such, incorporating two-stroke engines into HEVs is an effective way to reduce vehicle weight and optimize engine space. However, one downside is that the amount of unfired elements in the exhaust gas increases due to the air/fuel mixture being expelled into the exhaust system during the scavenging process. Moreover, combustion can become unstable due to the large volume of residual burned gases in the cylinder. To address these issues, we propose a two-stroke engine equipped with intake and exhaust valves that directly inject fuel into the cylinder. In our first report, we presented an engine design and method that enable high scavenging efficiency and stable combustion in a two-stroke engine [1]. In this second report, we share the results of our research aimed at improving fuel efficiency and achieving low emissions, all while maintaining the high performance typical of a two-stroke engine. To enhance fuel efficiency, the amount of burned gas was optimized by adjusting the timing and lifting the intake and exhaust valves. Lean combustion was achieved by leveraging the high temperature in the cylinder, utilizing its excellent ignitability. Additionally, it has been reported that THC emissions—a common issue in two-stroke engines—are reduced by preventing unburned gas from being expelled into the exhaust pipe through the adoption of in-cylinder direct injection.
Sakurai, Yota, Hisano, Atsushi, Saitou, Masahito, Ichi, Satoaki
Study on CO 2 Absorption via Atomization Utilizing Surface Texturing and Surface Energy for Small Engine Applications2025-32-007611/3/2025
In response to the stringent CO2 regulations set to be enforced in Europe in 2030, there is a global demand for innovative technologies to significantly reduce CO2 emissions from internal combustion engines used in trucks, ships, and other applications. For this reason, future power sources are anticipated to adopt a three-pronged approach: electrification; hydrogen fuel used in fuel cells or internal combustion engines; and synthetic fuels (e-fuels) produced from renewable energy-sourced hydrogen, as approved by the European Commission (EC), and from raw materials that capture CO₂ directly from the atmosphere via the Direct Air Capture (DAC) method, combined with internal combustion engines. In this study, we aimed to absorb and capture “Green” CO₂ emissions from e-fuel and carbon-neutral (CN) fuels combined with internal combustion engines by investigating a method that atomizes a CO₂-absorbing solution. This approach involved spraying the solution and impingement the droplets within the exhaust pipe to promote surface absorption reactions with CO₂ in the gas flow. By spraying an amine-based CO2 absorbent onto an impingement plate that has been especially surface textured and further treated with heating, we were able to enhance the surface area and control the surface energy of the CO2 absorbent. This approach opens up new possibilities for improved CO2 absorption reactions.
Nohara, Tetsuo, Nara, Shotaro, Kawamoto, Yuki, Fukushima, Naoya, Ochiai, Masayuki
Automated Calibration of Heavy-Duty Low NO x Aftertreatment System Controls using Deep Learning and Global Optimization Methods2025-01-040210/7/2025
Heavy duty diesel engines provide a robust power plant for transportation applications for both on highway and off road applications. Control of criteria pollutants such as particulate matter and NOx at tailpipe for these applications based on standards set by regulatory bodies such CARB and EPA is critical. SwRI has demonstrated capability to achieve 0.02 g/bhp-hr. tailpipe NOx standard through the application of a model based controls in EPA and CARB funded projects. This control mechanism enables precise urea dosing for both steady state and transient conditions by leveraging estimated ammonia storage state in a dual dosing system using a set of chemical kinetics-based SCR observer models. This controller is highly nonlinear, with a significant amount of controller tuning with up to 55 calibratable parameters. In order to improve the accuracy and reduce the time required for calibration of this controller, this work proposes the deployment of a Deep Learning-based SCR plant model in conjunction with a Genetic Algorithm based optimization script in a closed loop with the low NOx controller that can enable identification of near-optimal controller calibration in a simulation environment. This work describes the optimization framework and its validation with real-world experimental data. The calibration determined in this framework was able to achieve 0.02 g/bhp-hr for regulatory cycles consisting of CFTP, HFTP, RMC, and LLC. A quantitative and qualitative analysis on the results from this proposed framework is performed and is compared against existing expert driven manual calibration process.
Chundru, Venkata Rajesh, Rajakumar Deshpande, Shreshta, Sharp, Christopher, Gankov, Stanislav
Development of a Self-Adjusting Engine Out NOx Prediction Model Using Tailpipe O2 Measurements2025-01-038110/7/2025
On-Board Diagnostic (OBD) strategies utilize a predictive model to estimate engine out NOx levels for a given set of operating conditions to ensure the accuracy of the Nitrogen Oxides (NOx) sensor. Furthermore, this model is also used to determine urea dosing quantities in situations where the NOx sensor is unavailable such as cold starts or as a reaction to a NOx sensor plausibility failure. Physics-based NOx prediction models guarantee high levels of accuracy in real-time but are computationally expensive and require measurements generally not available on commercial powertrains making them difficult to implement on controllers. Consequently, manufacturers tend to adopt a mathematical approach by estimating NOx under standard operating conditions and use a variety of correction factors to account for any changes that can influence NOx production. Such correction factors tend to be outcomes of base engine calibration settings or outputs of models of other related sub systems and may not accurately capture the effect of component level drifts that directly influence NOx production such as mass air flow (MAF) sensor drifts, humidity variations, exhaust gas recirculation (EGR) rate variations, etc. Since mathematical approaches approximate physical phenomena, errors in any of the inputs tend to be compounded, thereby diminishing the accuracy of the final output. The method presented in this material focuses on using lambda values derived from tailpipe O2 measurements as the sole input to adjust the NOx model since it is a direct representation of the quality of combustion and accounts for variations in operation that can influence NOx production. This produces an easy-to-implement “self-adjusting” NOx model strategy that is consistent with the physics of NOx formation without requiring any additional hardware and ensures high levels of accuracy required to guarantee OBD robustness.
Sunder, Abinav, Suresh, Rahul, Polisetty, Srinivas
The VERT GPF-Retrofit Program for Cleaner Urban Mobility within the HORIZON Europe AeroSolfd Project2025-24-00959/7/2025
Launched in 2022, AeroSolfd, a HORIZON Europe project, aims to advance clean urban mobility by developing affordable and sustainable retrofit solutions for gasoline vehicles. This three-year initiative addresses not only tailpipe emissions but also brake emissions and pollution in semi-enclosed environments. Within AeroSolfd, the Swiss-based VERT association focuses on reducing tailpipe emissions using state-of-the-art Gasoline Particulate Filter (GPF) technology featuring an uncoated ceramic multicell wall-flow filter. VERT, in partnership with HJS, CPK, BFH, developed and tested a GPF-retrofit system at Technology Readiness Level 8 (TRL 8). Results demonstrate over 99% filtration efficiency for particles smaller than 500 nm on standard cycles (WLTC) and real-world driving cycles (RDE). Forty-two gasoline vehicles (GDI and PFI) were retrofitted with the GPF retrofit across Germany, Switzerland, Israel, and Denmark over a 6 to 8-month operational period. No issues were observed with filter regeneration, or increased fuel consumption, noise, drivability or secondary emissions. This paper presents the GPF retrofit program and field trial results.
Rubino, Lauretta, Mayer, Andreas C., Lutz, Thomas W., Czerwinski, Jan, Larsen, Lars C.
Visualization of Atomized Droplet Behavior and Distribution under Two-Layer Multiphase Flow in a Urea SCR Systems2024-32-00814/18/2025
Urea SCR system, installed in diesel engine vehicles such as trucks and agricultural machinery, is widely used as an exhaust gas aftertreatment system that efficiently purifies NOx, an environmentally harmful substance. Furthermore, the Urea SCR systems may be installed in hydrogen/carbon-neutral fuel engines, and biofuel aircraft engines aiming to achieve carbon neutrality. However, an important problem is the degradation of NOx purification performance caused by urea crystallization due to an undesired reaction of urea water solution (UWS) and clogging of the exhaust pipe due to the formation of deposits caused by an unknown number of atomized UWS behaviors, mainly during idling and low-speed operation when the pipe temperature is relatively low. The problem is that the UWS behavior of the atomized UWS is not well understood. To solve these problems, it is necessary to clarify the complex two-phase flow phenomenon of gas and droplets in the exhaust pipe, which is still unknown. We believe that these approaches can be applied to CO2 absorption systems as well as to urea SCR systems [1]. Hence, a new CAE method is proposed in which visualization experiments simulating the inside of an exhaust pipe are conducted, gas and droplet distribution data are obtained by PIV (Particle Image Velocimetry) from the results, and these are applied to DDM (Discrete Droplet Model) as experimental coefficients. In this study, we attempted to clarify the behavior of UWS under a two-phase flow in more detail by visualization of injected behavior, PIV analysis, and distribution measurement using a high-speed camera with higher sensitivity than before to improve the accuracy of this CAE method.
Ono, Joe, Nohara, Tetsuo, Nara, Shotaro, Kawamoto, Yuki, Fukushima, Naoya, Ochiai, Masayuki
Gasoline Particulate Filter Modeling with Catalytic Washcoat and Ash Accumulation and Transient Soot Distribution Prediction2025-01-84834/1/2025
The upcoming EURO 7 and EPA Tier 4 regulations and the possible China 7 are expected to tighten the tailpipe particulate emissions limits significantly. High performance Gasoline Particulate Filters (GPFs) with high filtration efficiency and low pressure drop would be mandated for gasoline engines to meet these stringent regulations. Due to packaging constraints, GPFs are often coated with three-way catalyst (TWC) materials to achieve four-way functionality. Ash accumulation in GPFs also has a significant impact on the performance of GPFs. This paper utilizes 3D CFD to predict the transient filtration efficiency and pressure drop of a washcoated GPF with ash accumulation during the soot loading process. Simulation results show a decent match with experimental data. The 3D CFD model also provides detailed information on soot penetration in the GPF wall substrate and soot cake characteristics on the wall. These information can be crucial for GPF wall substrate design and washcoating strategy design.
Yang, Pengze, Cheng, Zhen
Prediction and Control of Long-Term System Degradation for a Light-Off SCR in an Ultra-Low NOx Aftertreatment System2025-01-84884/1/2025
The heavy-duty low NOx program funded by EMA at Southwest Research Institute (SwRI) evaluates a combination of engine and advanced aftertreatment systems to achieve a 0.035 g/bhp-hr tailpipe NOx standard. This work emphasizes improvements to the light-off SCR (LO SCR) model used for low NOx controls. Two key mechanisms drive these improvements: the first is a real-time feedback system that utilizes the LO SCR outlet NOx sensor for short-term corrections to the model state, and the second involves adjustments to the dosing mechanism based on long-term trends in dosing signals compared to predicted NH3 consumption, derived from LO SCR inlet and outlet NOx sensors, referred to as long-term trim. An algorithm is incorporated to differentiate the LO SCR outlet NOx sensor readings into NOx and NH3 components based on cross-correlation between inlet and out NOx sensors termed as speciation. The integration of this speciation algorithm with both short-term and long-term trim mechanisms significantly enhances the accuracy of the model estimated NH3 storage state, as well as the prediction of outlet NOx, and NH3 levels under various transient conditions, including CFTP, HFTP, RMC, and LLC cycles. This improved accuracy in the LO SCR observer model enables more precise control of transient tailpipe NOx in the system.
Chundru, Venkata Rajesh, Adsule, Kartik, Sharp, Christopher
Vibration Measurement on Diesel Engine Components under Adverse Conditions in Brazilian Application2024-36-002112/20/2024
The objective of this study is to investigate the root cause of cracks detected in the Turbocharger bracket belonging to the engine Mercedes-Benz OM471 (Power: 390kW, Torque: 2600Nm) from Vehicle Truck Mercedes-Benz Actros 2651LS 6x4 Euro V. The investigation started with the instrumentation of every related component (besides the bracket itself, the charge air pipe, the exhaust pipe and also the crankcase for reference) in order to perform a vibration measurement. The necessary equipment to execute this procedure, included accelerometers, temperature sensors, strain gages and an inductive engine speed sensor. All data had to be acquired directly from real application conditions in vehicle, maximum load of 74 ton in a previously defined mountain road track, due to the impossibility to generate similar results in comparison to the ones detected on road through bench tests (or any other in-door experiment). The bracket position is located on the right side of a diesel combustion engine, also known as “engine hot side”, and work under temperatures in a range from 300 to 400 Celsius degrees. The development of a solution to allow the measurements to occur under such inhospitable conditions became a mandatory step of the investigation. The addition of a cooling system for the accelerometers, its adaptation and also the installation in the vehicle had been a challenging operation in order to reach the necessary results. The analysis of the raw data (speed, acceleration, strain and temperature) through Fast Fourier Transformation calculation (FFT) led to the exact determination of the root cause. With a clear understanding of the part behavior, assertive proposals of solution could be developed thanks to the answers obtained in the results of these measurements.
Feijó, Igor Sommerfeld, Gonçalves, Carlos Aurélio Bustamante
Development of an Automated Testbench for Functional Testing of Dosing Unit2024-28-020212/5/2024
Increasingly stringent emission regulations continue to be legislated around the world to significantly minimize pollutants released to the air by internal combustion engines. After Treatment Systems (ATS) meant for reducing oxides of nitrogen (NOx) in the exhaust into non-harmful species have evolved at a rapid pace over the past two decades. Stringent emissions requirements have driven complex ATS architecture through sensors to measure delta-pressure, NOx, and temperatures. Accurate and precise performance of individual components as well as the integrated ATS is required to ensure regulatory compliance and efficient performance. Both of which require substantial amounts of performance and validation testing. Manufacturers have been developing the ability to accurately and efficiently test the ATS components. To meet the norms for tail pipe or stack emissions of NOx in ‘as new’ condition and during the entire ‘emissions useful life (EUL)’ of the ATS, all components of an ATS must perform with high accuracy, every single time. A well designed ‘automated testbench’ ensures better accuracy in testing the functionality of many parts of the ATS, as rapidly as possible. Dosing Unit (DU), also known as the Urea Dosing Unit, in the ATS is responsible for delivering urea as needed into the exhaust airstream thereby helping in the reduction of NOx from the tail pipe or exhaust stack in the SCR (Selective Catalytic Reduction). This paper describes the development of an automated testbench to validate the performance of the dosing unit. The test bench is designed such that both new and used (returned from field) ATS can be tested or evaluated for performance. The automated testbench for urea dosing has been developed at the Cummins Technical Center in India (CTCI) keeping in mind the needs for similar testbenches for Cummins use in other parts of the world. The test bench design, build, and test process and protocol have been formulated such that the same test bench can be used to test urea dosing units to meet emission standards defined by EPA, CARB, EURO, NS, and other international standards.
Raut, Pratiksha C, Ottikkutti, Pradheepram, Phadke, Abhijit Narahari, Magar, Vijay A.
Catalyzed Gasoline Particulate Filter Performance from Fresh to Full Useful Life2024-01-431111/5/2024
The gasoline particulate filter (GPF) represents a durable solution for particulate emissions control in light-duty gasoline-fueled vehicles. It is also seen as a viable technology in North America to meet the upcoming US EPA tailpipe emission regulation, the proposed “Multipollutant Rule for Model Year 2027”. The goal of this study was to track the evolution of tailpipe particulate emissions of a modern GTDI light duty vehicle under typical North American mileage accumulation; from a fresh state to 4000-mile, and finally to its full useful life of 150,000-miles. For this purpose, a production TWC + GPF after-treatment system was installed in place of the T3B85 TWC-only system. Chassis dyno emissions testing was performed at the pre-determined mileage points with on-road driving conducted for the necessary mileage accumulation. This report will show the outstanding filtration durability and enhanced particulate control and of the current GPF technology all the way to 150,000 miles for the typical North American application. The report will also demonstrate that a coated CC2 GPF solution is an acceptable substitution for a flow through TWC catalyst for gaseous emissions performance, using an older 1st generation GPF washcoat technology without system optimization efforts. Noting that the investigation is an extension of previously reported results from the GPF performance from 0 to 4000-miles which characterized the early life evolution of tailpipe particulate emissions, specifically mass (PM) and number (PN).
Craig, Angus, Warkins, Jason, Beattie, James, Nipunage, Sanket, Moser, David, Day, Ryan, Banker, Vonda
Physics Based On-Board Exhaust-Temperature Prediction Model for Highly Efficient and Low-Emission Powertrain2024-01-427311/5/2024
Modern automotive powertrains are operated using many control devices under a wide range of environmental conditions. The exhaust temperature must be controlled within a specific range to ensure low exhaust-gas emissions and engine-component protection. In this regard, physics-based exhaust-temperature prediction models are advantageous compared with the conventional exhaust-temperature map-based model developed using engine dyno testing results. This is because physics-based models can predict exhaust-temperature behavior in conditions not measured for calibration. However, increasing the computational load to illustrate all physical phenomena in the engine air path, including combustion in the cylinder, may not fully leverage the advantages of physical models for the performance of electric control units (ECUs). This study proposes an onboard physics-based exhaust-temperature prediction model for a mass-produced engine to protect the engine exhaust system and reduce exhaust emissions. The combination of simplified combustion in the cylinder and heat transfer in the engine airpath model enables us to minimize the calculation load in the ECU and simultaneously predict the exhaust temperature. In-cylinder combustion is estimated accurately using the basic engine operation parameters, volumetric efficiency, and ignition timing. Convection heat transfer, thermal conduction, and radiation are considered in this model in a simple one-dimensional form. Results show that the predicted exhaust temperature is consistent with the measured temperature during engine dyno and vehicle testing. Even under the EV operation mode in a series hybrid system, low heat loss from the exhaust gas to the pipe wall owing to the heat transfer of natural convection is predicted accurately. Additionally, the detailed heat-transfer model accurately predicts the exhaust temperature after the engine is started in the series hybrid mode. Thus, this newly developed physical exhaust-temperature model is suitable for the engine exhaust-system protection and catalyst-activation management of our mass-produced vehicle.
Yamaguchi, Seiya, Tomita, Masayuki, Urakawa, Shinji, Ookubo, Seiichi
Impact of AdBlue Composition and Water Purity on Particle Number Increase2024-01-30127/2/2024
Previous studies have shown that dosing AdBlue into the exhaust system of diesel engines to reduce nitrogen oxides can lead to an increase in the number of particles (PN). In addition to the influencing factors of exhaust gas temperature, exhaust gas mass flow and dosing quantity, the dosed medium itself (AdBlue) is not considered as a possible influence due to its regulation in ISO-standard 22241. However, as the standard specifies limit value ranges for the individual regulated properties and components for newly sold AdBlue, in reality there is still some margin in the composition. This paper investigates the particle number increase due to AdBlue dosing using several CPCs. The increase in PN is determined by measuring the number of particles after DPF and thus directly before dosing as well as tailpipe. Several AdBlue products from different sources and countries are measured and their composition is also analyzed with regard to the limit values regulated in the standard. This shows that differences in the PN-increase can be determined for the various products. In addition, two measurements are carried out with pure water as a main component of AdBlue in the form of single and double-distilled water. Interestingly, the dosing of pure water also shows an increase in PN depending on the purity of the water. Furthermore, two AdBlue products are artificially aged in order to violate the standardized limit values, which is a feasible use case with regard to ISC tests, and subsequently measured. Since these impurities cannot be influenced but have a noticeable effect on the measured PN, it is important to quantify this and, if necessary, to take it into account in legislation.
Herold, Tim, Noone, Patrick, Beidl, Christian, Boldt, Thomas, Hochholzner, Michael, Kontin, Sinisa
Experimental and Simulation Study of Zero Flow Impact on Hybrid Vehicle Emissions2024-37-00366/12/2024
Combustion engines in hybrid vehicles start and shut off several times during a typical passenger car trip. Each engine restart may pose a risk of excessive tailpipe emissions in real-drive conditions if the after-treatment system fails to maintain an adequate temperature level during engine off mode. In view of the tightening worldwide tailpipe emissions standards and real-world conformity requirements, it is important to detect and resolve such risks via reliable and cost-effective engineering tools that can perform accurate analysis of the thermal and chemical behavior of exhaust systems. In this work, we present a catalyst model that predicts the 3D thermal and chemical behavior under normal and zero flow conditions. Particular emphasis is given to the phenomena of free convection and thermal radiation dominating the heat transfer at zero flow. Next, we examine the impact of zero-flow duration on the exhaust system temperature and subsequent emissions risk and we validate the obtained results with respective measurements from experimental tests. Overall, the model can accurately predict the temperature distribution inside the catalyst and tail pipe emissions, under a broad range of operating conditions. The model can subsequently be used to study several scenarios of vehicle hybridization schemes, as well as techniques to minimize the risk of zero flow operation by proper system design and control.
Emmanouil, Valesia, Koltsakis, Grigorios, Kotoulas, Costas
The Development of a Zeolite-Based Cold-Start Catalyst (CSC) for China 6b Vehicles (Conventional & Hybrid) to Meet the Next Chinese Vehicle Emission Standard, Part II2024-01-26564/9/2024
This is a follow-up report about the development of a cost-effective Palladium (Pd) zeolite-based (HC/NOx trap type) cold-start catalyst (CSC) [1] to meet the future more stringent Chinese vehicle tailpipe emission standard. The impacts of Pd /stabilizer combination within zeolite for the HC/NOx trapping efficiency, the high temperature aging and the durability of the CSCs will be demonstrated by the laboratory results within this paper. The feasibility of a Cu zeolite, a popular non-precious metal ion- zeolite CSC for vehicle applications with respect to cost saving options will be demonstrated. A more complete picture of the effects of PGM/stabilizer within the zeolite to the functions of a CSC will also be summarized in this paper. All results indicate clearly that without the PGM/stabilizer within the zeolite, it would be difficult for the zeolite-based HC/NOx trap type CSC catalyst to be practically used for a vehicle application. The bag and second by second vehicle test results with a Pd/stabilizer-zeolite based CSC showing the decrease in cold-start emissions on a China 6b hybrid vehicle (HEV) will meet the projected future more stringent Chinese tailpipe emission standard. The future development plan for a CSC as a new catalyst technology in vehicle applications will also be outlined.
Xu, Lifeng, Zhao, Fucheng, Wei, Hong, Zhao, Pengfei, Zhao, Jiajia, Wang, Lin, Qian, Wangmu, Qian, Menghan
3-Dimensional Numerical Simulation and Research on Internal Flow about Different EGR Rates in Venturi Tube of EGR System for a Turbocharged Diesel Engine2024-01-24184/9/2024
Exhaust gas recirculation technology is one of the main methods to reduce engine emissions. The pressure of the intake pipe of turbocharged direct-injection diesel engine is high, and it is difficult to realize EGR technology. The application of Venturi tube can easily solve this problem. In this paper, the working principle of guide-injection Venturi tube is introduced, the EGR system and structure of a turbocharged diesel engine using the guide-injection Venturi tube are studied. According to the working principle of EGR system of turbocharged diesel engine, the model of guide-injection Venturi tube is established, the calculation grid is divided, and it is carried out by using Computational Fluid Dynamics method that the three-dimensional numerical simulation of the internal flow of Venturi tube under different EGR rates injection. The flow field state, velocity field, pressure field and exhaust gas concentration parameters of the mixture formed by air and EGR exhaust gas in Venturi tube are analyzed. The calculation results show that the EGR rate has a great impact on the initial pressure recovery effect before the compression section of the Venturi tube. The greater the EGR rate ejection amount, the worse the pressure recovery effect. In order to meet the requirement of large EGR rate, the Venturi diffuser angle should be reduced while keeping the length of the diffuser section unchanged. The diameter of the throat of the mixing section and the diameter of the EGR ejection port can be appropriately increased, the number of ejection ports can also be appropriately increased. This paper also proves that the Venturi tube of the ejector EGR system can overcome the pressure deficit between the exhaust pipe and the intake pipe of the turbocharged direct-injection diesel engine, which verifies the feasibility of the EGR Technology of the turbocharged direct-injection diesel engine through the Venturi tube.
Yang, Shuai, Yan, Kai, Liu, Haifeng, Liu, Hairan, Li, Tong
Soot Sensor Elimination with DPF Substrate Failure Monitoring2024-26-01531/16/2024
The automobile industry is going through one of the most challenging times, with increased competition in the market which is enforcing competitive prices of the products along with meeting the stringent emission norms. One such requirement for BS6 phase 2 emission norms is monitoring for partial failure of the component if the tailpipe emissions are higher than the OBD limits. Recently PM (soot) sensor is employed for partial failure monitoring of DPF in diesel passenger cars.. PM sensor detects soot leakage in case of DPF substrate failure. There is a cost factor along with extensive calibration efforts which are needed to ensure sensor works flawlessly. This paper deals with the development of an algorithm with which robust detection of DPF substrate failure is achieved without addition of any sensor in the aftertreatment system. In order to achieve this, a thermodynamic model of DPF substate was created using empirical relations between parameters like exhaust flow rate, exhaust gas temperature and soot mass content. The modeling was done in both empty (no soot) and filled (threshold soot content) DPF substrate conditions. There were two methodologies, namely integration method and normalization method. In integration method the pressure drop across DPF substate in actual running condition is cumulatively summed up and compared with the integrated modelled value achieved from the thermodynamic model. If the ratio between modelled and actual crosses the threshold value, a DPF substrate failure flag is raised. In normalization method, actual pressure drop across DPF is corrected using empirical thermodynamic relations for exhaust temperature and soot mass content. The corrected pressure drop is normalized for the exhaust flow rate and then averaged based on release conditions. If the averaged values is lower than the threshold, a DPF substrate failure flag is raised. DPF substrate failure is intimated only when both the methodologies raise the failure flag. The algorithm was tested with actual failed DPF sample and robust detection was observed (more than 90% detection accuracy) and no misdetection.
Jain, Praveer Kirtimohan, Yadav, Omkar, Chendil, Chellapandi, Krishnaraj, P, R, Sivasubramamanian, Daithankar, Parag Narsinha, Shanmugam Ramakrishnan, Muthu
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
Novel Exhaust System Architecture for Petroleum Oil Tanker Application Vehicle2024-26-03451/16/2024
Petroleum Oil, Lubricants (POL) & Liquefied petroleum gas (LPG) tanker vehicles are special application segment that holds a significant Market share for commercial vehicles. These vehicles need to comply additional Safety regulations specified by Petroleum and explosives safety organization (PESO). For compliance to Rule-70, Protective heat shield on exhaust system needs to be designed and validated in order to avoid any catastrophic failure. The paper demonstrates the methodology to identify the worst case scenario for the existing commercial vehicle segment. Based on detail digital mock up (DMU) review Metallic heat shield was designed on after treatment system (ATS). The flexible heat shield was designed for exhaust pipe & joints in order to restrain the heat flow to the surrounding aggregates. After finalising design, CFD analysis was carried out to find out the thermal effects on various components and results within acceptable limits. After digital validation proto parts were manufactured as per final design. The physical validation was conducted at max power & max torque conditions. It is found that the actual test result where in line with CFD simulation.
Sahoo, Rajanikanta, Khandagale, Anup, Manoharan, Logeshwaran, Kumar, Pravin, Petale, Mahendra Arvind
A Study on the Effect of an Acoustic Valve in the Exhaust Silencer for Noise Reduction in Automotive Application2024-26-02201/16/2024
Customer preference towards quieter vehicles is ever-increasing. Exhaust tailpipe noise is one of the major contributors to in-cab noise and pass-by-noise of the vehicle. This research proposes a silencer with an integrated acoustic valve to reduce exhaust tailpipe noise. Incident exhaust wave coming from the engine strikes the acoustic valve and generates reflected waves. Incident waves and reflected waves cancel out each other which results in energy loss of the exhaust gas. This loss of energy results in reduced noise at the exhaust tailpipe end. To evaluate the effectiveness of the proposed silencer on the vehicle, NVH (Noise, vibration, and harshness) performance of the proposed silencer was compared with the existing silencer which is without an acoustic valve. A CNG (Compressed natural gas) Bus powered by a six-in-line cylinder engine was chosen for the NVH testing. After NVH evaluation, it was found that when using the proposed silencer, overall exhaust tailpipe orifice noise is reducing by 4-5 dB throughout the engine rpm range. In-cab noise at DEL (Driver ear level) is reducing by 2 dB throughout the engine rpm range except for 1200-1400 rpm range. Pass-by noise is reducing by 1 dB when vehicle is running in 3rd gear and it is reducing by 3 dB when vehicle is running in 4th gear.
Singh, Har Govind, Khandagale, Anup, Choudhari, Yogeshwar, Kalsule, Dhanaji, Petale, Mahendra
The future of carbon-neutral fuels for heavy-duty machines23TOFHP12_0912/1/2023
Decarbonization of commercial vehicles and off-highway machines is rapidly becoming a hot-button topic among regulators in the EU, Asia and North America. In addition to cracking down on emissions of light vehicles, various government agencies are now looking to reduce the tailpipe emissions from all manner of industrial equipment. Truck & Off-Highway Engineering attended an expert panel at the 2023 SAE COMVEC conference that covered renewable and low-carbon fuels as well as usage of hydrogen. The panel consisted of SMEs and engineers from various OEMs such as the Traton Group company MAN, Aramco and Ballard. They discussed the various ways in which these industries can reduce or even eliminate emissions from their machines while also discussing the economic feasibility of doing so.
Wolfe, Matt
Numerical Investigation on the Design and Development of Automotive Exhaust Muffler –A Case Study2023-28-008511/10/2023
Attaining better acoustic performance and back-pressure is a continuous research area in the design and development of passenger vehicle exhaust system. Design parameters such as tail pipe, resonator, internal pipes and baffles, muffler dimensions, number of flow reversals, perforated holes size and number etc. govern the muffler design. However, the analysis on the flow directivity from tail pipe is limited. A case study is demonstrated in this work on the development of automotive muffler with due consideration of back pressure and flow directivity from tail pipe. CFD methodology is engaged to evaluate the back pressure of different muffler configurations. The experimental and numerical results of backpressure have been validated. The numerical results are in close agreement with experimental results. It was observed that the influence on back pressure with reducing the quantity of baffle plate, Increasing the tail pipe diameter and twin tail pipe with bypassing flow through inner pipe are 2.7%, 1.4% and 34.4%, respectively. The impact of tail pipe angle on flow directivity is assessed based on the flow uniformity index. Effect of each operating parameter on the back pressure is evaluated with statistical approach.
Baskar, Subramaniyan, Lingala, Vivek, Raju, Kumar
Simulation of Temperatures of Three Way Catalytic Converter for Motorcycles at Higher Temperatures2023-01-181510/24/2023
For a quick reach to the operating temperatures, the three way catalytic converter is recently located closer to the engine and subjected to higher temperatures than before. At the same time, the three way catalytic converter has upper thermal limits. Therefore, the operating temperatures have to be estimated accurately in the early period of product development. In this research, the four analysis methods are linked with the one-dimensional engine cycle simulation to achieve the goals. Firstly, for the estimation of gas temperatures at the exhaust port of the engine, the combustion analysis using the 3D-CFD was conducted to accurately simulate the way the heat was generated. Then, for the estimation of heat dissipation from the exhaust system to the atmosphere, the heat conduction analysis coupled with the air flow analysis around the vehicle body using the 3D-CFD was conducted. To take into considerations the heterogeneity of reactions in the three way catalytic converter, the gas flow in the exhaust pipe was also analyzed using the 3D-CFD. As the last step for estimation of temperatures in the 3-way catalysis, the reactions in the catalysis were analyzed to take into account the heat generated by the oxidation of unburnt hydrocarbons promoted by the catalysis. The correlation between the estimation by this method and the actual measurement was taken in the five models having various engine configurations such as the number of cylinders and cooling methods, and vehicle configurations such as the scooter and the motorcycle. It has consequently been confirmed that this method allows estimation of temperatures in degrees Celsius inside the three way catalytic converter at higher temperatures as accurately as a maximum error of 5%. Thus, enabled is an accurate evaluation of parts layout to satisfy the heat resistance requirements of the three way catalytic converter at higher temperatures.
Shigeno, GENKI, Fujita, Shinji, yogo, toyoyuki
Impact from a variety of E10 and E20 gasoline formulations on PN10 and PN23 emissions evaluated in combination with advanced GPF technology generations2023-32-00289/29/2023
The study was aimed at assessing the impact of fuel quality on the PN10 and PN23 emissions. A total of 6 fuels having different level of ethanol, renewable components, additives, and aromatic hydrocarbons were tested on the test vehicle. In the first phase of the study, the emission tests were conducted removing the GPF present in the original aftertreatment system to measure the direct impact of different fuels on the tailpipe particle emissions. The emission results showed that heavy aromatics components lead to a significant increase in particle emissions while the fuel with renewable components and E20 emit less PN comparing to the E10 reference fuel. However, those fuel impacts became very small with a GPF present due to a high filtration efficiency independent of fuel type.
Chijiiwa, Ryoko, Rose, Dominik, Boger, Thorsten, Krueger-Venus, Jens, Cracknell, Roger, Williams, Rod
Coupled Engine and After-Treatment Simulation for Fuel Efficient EU7 Technologies2023-24-01048/28/2023
To achieve low tailpipe NOX emissions in Heavy-Duty engines, the rapid warm-up of the exhaust aftertreatment system (EAS) needs to be assisted by the adoption of new technologies to reduce engine-out emissions and increase the EAS conversion efficiency. Engine measures like cylinder deactivation, retarded start of the main injection, late intake valve closing, intake throttling and elevated idle speed can substantially increase the available exhaust gas enthalpy and temperature at the expense of additional fuel as has been shown in the literature. On the other hand, the exhaust system can be optimized in terms of hardware and controls, which is nowadays strongly supported by simulation. However, these simulation studies typically assume a fixed engine hardware and calibration and thus fixed engine-out simulation boundary conditions. Moving forward to tougher and real-world oriented legislation, the fixed cycle and engine-out boundary condition becomes insufficient. The present work proposes a model-based approach that covers both the engine and the aftertreatment system in a single simulation platform. To ensure the predictive nature of the simulation, all engine and aftertreatment models were calibrated with appropriate experimental techniques. The models are scalable depending on the application target; for most of the results of this work, we employ fast running 1d models. Using the holistic simulation approach, it is possible to virtually activate and optimize the settings of various engine parameters to obtain a good trade-off in terms of fuel penalty and tailpipe emissions. Due to the huge number of parameter combinations, the optimization process itself is a real challenge that is addressed in the present work and time-efficient workflows are demonstrated. The application cases presented emphasize on technologies expected to be relevant for upcoming legislation, including close-coupled SCR and active exhaust heating.
Tziolas, Vasileios, Koltsakis, Grigorios, CHATZIPARTALI, Kleoniki
Virtual Development of Control Coordinator for Engine and Aftertreatment Architecture Equipped with Diesel Fuel Burner2023-24-01038/28/2023
Heating devices are effective technologies to strengthen emission robustness of AfterTreatment Systems (ATS) and to guarantee emission compliance in the new boundaries given by upcoming legislations. Moreover, they allow to manage the ATS warm-up independently from engine operating conditions, thereby reducing the need for specific combustion strategies. Within heating devices, an attractive solution to provide the required thermal power without mandating a 48V platform is the fuel burner. In this work, a model-based control coordinator to manage the interaction between engine, ATS and fuel burner device has been developed, virtually validated, and optimized. The control function features a burner model and a control logic to deliver the needed amount of thermal energy, while ensuring ATS hardware protection. The coordinator has been optimized and validated through the virtual test campaign: the developed control function and a complete ATS model were integrated in the simulation environment, while different experimental engine out traces were used as input. By means of this tool, a preliminary emission performance assessment has been carried out comparing baseline ATS (Euro6d full capable) and a burner-equipped ATS; by several loops, an optimal burner strategy that minimizes tail-pipe emission was selected as well. Once the control design was deemed satisfactory, a real ATS equipped with a burner device was experimentally tested at engine dyno. The experimental campaign allowed to test the control design and assess the predictive capability of the virtual model in terms of tailpipe emission. It was found that the virtual model allowed to properly develop the control functions and to predict the emission reduction trend. From a methodology perspective, virtualization is confirmed to be a cost- and time-effective instrument to develop control logics and first-attempt calibration for their operative strategy.
Pozzi, Chiara, Ciaravino, Claudio, Donniacuo, Antonio, Ferreri, Paolo, Previtero, Giuseppe, Chen, Federico, Totaro, Nicola, Mital, Rahul
Direct and Indirect Exhaust Heat Recovery from Turbocharged Heavy-Duty Engine2023-24-01228/28/2023
Waste Heat Recovery (WHR) is one of the most viable opportunities to reduce fuel consumption and CO2 emissions from internal combustion engines in the transportation sector. Hybrid thermal and electrical propulsion systems appear particularly interesting because of the presence of an electric battery that simplifies the management of the electrical energy produced by the recovery system. The different technologies proposed for WHR can be categorized into direct and indirect ones, if the working fluid operating inside the recovery system is the exhaust gas itself or a different one whose sequence of transformations follows a thermodynamic cycle. In this paper, a turbocharged diesel engine (F1C Iveco) equipped with a Variable Geometry Turbine (VGT) has been tested to assess the energy recoverable from the exhaust gases both for direct and indirect recovery. A direct technology based on an auxiliary turbine placed in the exhaust pipe (turbo-compounding) has been considered and compared with an Organic Rankine cycle (ORC)-based recovery unit fed by the exhaust gases. A model-based comparison between the two technologies has been assessed in this paper. The input data were the result of an experimental campaign done on the exhaust gases of the F1C Iveco operated on a high-speed dynamometer test bench. Data on exhaust gas properties, turbocharger equilibrium and engine performances were collected for a wide range of engine operating conditions. Concerning the ORC-based power unit, the model uses the significant research experience done on the sector that set up the most relevant machine performances (expander and pump efficiency, engine backpressure produced, pinch points at the two heat exchangers) so giving the model high reliability. Preliminary data on a turbo-compounding system operated on the same engine were also measured so resolving the most important uncertainties of the recovery unit (engine backpressure produced, turbine and electrical generator efficiency, matching between the turbocharging unit). A preliminary assessment of the overall potential recovery when both technologies were present has been done, focusing the attention on heavy-duty engines.
Di Bartolomeo, Marco, Di Battista, Davide, Fatigati, Fabio, Cau, Giorgio, Cipollone, Roberto
HORIZON Europe Project AeroSolfd: GPF-Retrofit for Cleaner Urban Mobility2023-24-01148/28/2023
Ultrafine particles, in particular solid sub-100 nm particles pose high risks to human health due to their high lung deposition efficiency, translocation to all organs including the brain and their harmful chemical composition; due to dense traffic, the population in urban environments is exposed to high concentrations of those toxic air contaminants, despite these facts, they are still widely neglected. Therefore, the EU-Commission set up a program for clean and competitive solutions for different problem areas which are regarded to be hotspots of such particles. HORIZON AeroSolfd is an EU project, co-funded by Switzerland that will deliver affordable, adaptable, and sustainable retrofit solutions to reduce exhaust tailpipe emissions from petrol engines, brake emissions and pollution in semi-closed environments. VERT, a Swiss based international industry organization, has a long research history in the field of nanoparticle filtration and it is in charge of reducing tailpipe emissions of gasoline vehicles by using the best available retrofit filtration technology (BAT). VERT will apply the newest high-efficient GPF technology in three high mileage fleets, in Germany, Switzerland and Israel. The project will also serve as a platform to continue research on PN emissions as well as on secondary emissions from GDI and PFI petrol engines. In addition, the “high emitter phenomena” will be further analysed with a NPTI testing campaign of 1000 gasoline vehicles, including GDI, PFI and GPF equipped vehicles.
Rubino, Lauretta, Mayer, Andreas, Czerwinski, Jan, Lutz, Thomas, Larsen, Lars, Engelmann, Danilo, Lehmann, Martin
Challenges of Particulate Number above 10nm Emissions for a China 6 Compliant Vehicle to Meet Future Regulation2023-01-03774/11/2023
As the official proposal for emission regulation Euro 7 has been released by European Commission, PN above 10nm is taken into consideration for the ultrafine particulate emissions control. The challenges of GPF filtration efficiency emerge for the light-duty manufactures to meet the future emission standards. In the present study, a China 6 compliant vehicle was tested to reveal its performance over the China 6 standards and potential to meet the upcoming Euro 7. Three GPF product types (Gen 1, Gen 2, and concept Gen 3) were mounted to the tested vehicle. WLTC tests were conducted on chassis dynamometer in laboratory as well as a self-designed aggressive cycle (“Base Cycle”) tests. To explore the GPFs performance for PN emissions above 10nm against the proposed limit 6.0E11 #/km, PN emission above 10nm were measured in our laboratory tests for both engine out and tailpipe as well as the PN emission above 23nm. In addition, worst case RDE tests were carried out on the real road with PEMS. It was found that, when including particles down to 10nm, further improvement is needed for the current system, and the Gen 2 and concept Gen 3 products could be a promising path to meet the proposed standards with much higher filtration efficiency. Combined with possibly further extended RDE boundary conditions in Euro 7, the test results suggested that higher filtration efficiency filter products are likely required to comply with the tightened emission regulations.
Liu, Haixu, Li, Chunbo, Li, Weiwei, Feng, Xiangyu, Tao, Tinghong, Boger, Thorsten, Wang, Guodong, li, Gaojian, Yu, Guangyao, Lu, Heng, Li, Ruike, Qiang, Ren, Yuan, Guanlian
The Development of a Zeolite-Based Cold-Start Catalyst (CSC) for a Conventional China 6b Vehicle in Meeting the Next More Stringent Chinese Vehicle Emission Standards2023-01-02334/11/2023
A state of art Pd-zeolite based cold-start catalyst (CSC) or HC/NOx trap type of catalyst was codeveloped between Geely Automotive Company and Ningbo Kesen Exhaust Gas Cleaner Manufacturing CO. LTD. This CSC catalyst was added to the downstream of an existing catalyst system (TWC+CGPF) of a China 6b conventional passage car which was powered by a 1.5L turbo charge direct injection (1.5L GTDI) engine. The CSC significantly converted cold-start tailpipe NMHC emission and enabled the tailpipe emissions to meet the engineering targets of the projected next more stringent Chinese vehicle tailpipe emission standards in WLTC cycles. The vehicle tailpipe emission results with the addition of the laboratory simulated 120K km aged CSC also met the projected emission engineering targets of a fresh catalyst. Both the vehicle and laboratory results demonstrated the excellent ammonia adsorption and oxidation function of this CSC catalyst as a very efficient natural ammonia slip catalyst (ASC). Due to its independency of heating power (battery), CSC is a more cost-effective technology for both conventional and hybrid vehicles in converting both the tailpipe cold-start emissions (mainly NMHC) and eliminating ammonia slip over an aftertreatment system equipped with electrically heated catalyst (EHC) and an ASC catalyst for meeting the future Chinese low emission standards.
Xu, Lifeng, Zhao, Fucheng, Wei, Hong, Zhao, Pengfei, Qian, Wangmu, Qian, Menghan
A Combined Automotive Exhaust Heat Recovery Technique Using Phase Change Material and Jet Impingement Heat Transfer with Wall Protrusions and Baffle2022-28-051212/23/2022
Automotives play a very important role in day-to-day human lives. The exhaust gas emitted from automotive vehicles of current technologies is one of the major contributions to global temperature increment. It is important to develop a system that can conserve energy and incorporate it into current vehicles which are in use. Phase change materials (PCM) are well known for energy storage applications because of their crucial thermophysical property known as latent heat of fusion. The gas from the exhaust pipe of automobiles can be considered a turbulent jet. With this assumption in this study, a system is proposed by combining jet impingement and phase change material at the exhaust pipe of automobiles to recover the thermal energy which is being let out into the atmosphere as waste. Liquid Gallium is chosen as a phase change material for this study because of its high thermal conductivity nature compared to other hydrocarbon-based phase change materials. Initially, a combined numerical study of jet impingement heat transfer and phase change material is performed and the results are chosen as a benchmark. Later the study extends with the application of flow baffles and wall protrusions to enhance energy conservation. The enhancement study comprises four different baffle designs with two different heights and spacings. Also, two different wall protrusion models with different protrusion wavelengths. The numerical results show that the application of flow baffles promisingly enhances energy recovery. On the other hand, the application of wall protrusion shows a significant increment in energy recovery but it is important to choose the proper wavelength for wall protrusion.
Jambulingam, Bharanitharan, Senthilkumar, Sundararaj
Machine-Learning-Based Emission Models in Gasoline Powertrains—Part 2: Virtual Carbon Monoxide03-16-06-004512/12/2022
In this work, tailpipe carbon monoxide emission from a gasoline powertrain case study vehicle was analyzed for off-cycle (i.e., on road) driving to develop a virtual sensor. The vehicle was equipped with a portable emissions measurement system (PEMS) that measured carbon monoxide concentration and exhaust volumetric flowrate to calculate the mass of carbon monoxide emitted from the tailpipe. The vehicle was also equipped with a tailpipe electrochemical NOx sensor, and a correlation between its linear oxygen signal and the PEMS-measured carbon monoxide concentration was observed. The NOx sensor linear oxygen signal depends on the concentration of several reducing species, and a machine learning model was trained using this data and other features to target the PEMS-measured carbon monoxide mass emission. The model demonstrated a mean absolute percentage error (MAPE) of 19% when using 15 training drive cycles. Finally, a virtual carbon monoxide sensor was developed by removing the tailpipe NOx sensor information from the model feature set and predicting tailpipe carbon monoxide mass. The virtual model MAPE was shown to increase by 5% compared to the earlier version with a tailpipe NOx sensor over the same number of training, validation, and test drive cycles. The minimal degradation in accuracy for the virtual model was hypothesized to result from the fact that narrowband oxygen sensors may contain information regarding how rich or lean the exhaust gas is compared to stoichiometric conditions. This is analogous to the information provided by a wide-band oxygen sensor, but potentially with reduced resolution and accuracy. The data-driven approach was able to produce a novel virtual tailpipe carbon monoxide sensor in a gasoline powertrain using only common powertrain and emission sensors.
Kempema, Nathan J., Sharpe, Conner, Wu, Xiao, Shahabi, Mehrdad, Kubinski, David
Innovative Exhaust System Component that Attenuates Standing Waves with Minimized or Eliminated Leakage2022-01-510412/12/2022
Passenger cars with internal combustion engines traditionally use exhaust systems with resonators and mufflers to provide combustion tailpipe orifice noise attenuation. Those elements require acoustic volume which puts constraints on vehicle package space and adds weight to the exhaust system and vehicle. Passive and active valves are also used in the exhaust systems to attenuate noise, helping to reduce muffler volume and reduce other noises like cooldown noise or other noise, vibration, and harshness (NVH) issues that must be dealt with. To attenuate tailpipe noise, we can also reduce the amplitude of standing waves in long uninterrupted pipes of exhaust systems with specifically designed openings to the external environment which does not require a significant increase in weight and vehicle package space. Standing wave management (SWM) is providing such openings and its placement is driven by standing wave physical properties such as wavelength. The theory of using SWM is that open area attenuates noise due to the reduction of standing wave amplitude, and the open area amount required depends on the acoustic targets. Proper placement determines overall effectiveness. One of the primary issues with making openings in the exhaust system pipe is gas emissions below the vehicle and the risk of carbon monoxide (CO) intrusion into the passenger cabin. SWM can also be used with an additional component called an idle pulsation cover (IPC) to reduce leakage/emissions to the ambient. Analysis of the system using tools, such as GT-Power, Ricardo WAVE, and computational fluid dynamics (CFD), help determine the number of required SWM elements, and the leakage risks for the application with or without the use of the IPC. Low engine revolutions per minute (rpm) is where the largest risk for leakage occurs. Emissions testing can help determine the CO intrusion risk, carbon dioxide (CO2) leak, and IPC effectiveness. IPC effectiveness is determined by volume and the fundamental firing frequency. Consideration of SWM location relative to the cabin can help determine the need for the IPC. Manufacturing techniques for SWM are determined by the application. The use of ribs with optimal location for the holes provides minimal leakage to the ambient. The number of SWM components is also determined by the acoustic targets and available package space. Other similar devices are available but do not directly provide a unique solution to the leakage issues caused by transient flow.
Thomas, Stephen
Emission Performance and Durability Validation Methodology for Heavy Commercial Vehicle After-treatment Systems2022-28-032710/5/2022
To meet stringent emission norms and commercial vehicle customer demands, the selection of an after-treatment system (ATS) plays a considerable role. Therefore, the selected ATS should substantially reduce nitrogen oxide emission by proper decomposition of ammonia and particulate matter without significantly increasing the thermal stress on DPF. Though the BS-VI after-treatment architecture is derived from EURO-VI, only a certain level of technology for the vehicle operating conditions in India can be implemented. However, numerous vehicle operating condition challenges in the Indian market must be explicated. Correspondingly, it should be addressed with a robust durability validation methodology to enhance the ATS product performance in challenging environments. This paper discusses SCR catalysts emission performance and ammonia decomposition durability validation methodology for commercial vehicles. In addition, during various vehicle duty cycle conditions, the effectiveness of DPF and DOC is recognized based on minimized soot loadings in the DPF based on soot regeneration strategies. Hence, on the one hand, the design of DOC is optimized to recognize passive soot regeneration effectively by oxidation NO into NO2. On the other hand, for facilitating regeneration temperature (DOC at >500°C) during HC dosing in the exhaust pipe, DOC catalyst effectiveness is also essential. Accordingly, based on the scenario above, the impact of soot loading and back pressure on DPF material durability is also validated for vehicle operating conditions.
Subramanian, Karthikeyan, A, Suresh, Mahadevan, Sathyanandan, Sadagopan, Krishnan
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
EHC Development for HEV Emission Control2022-01-10128/30/2022
In the recent years and near future, the automotive environmental regulations have been and will be more stringent than ever before. The reduction of cold start tailpipe emission is the key for exhaust aftertreatment and emission control. As one of the effective catalyst heating approaches, EHC can be applied to reduce catalyst L/O time at engine cold start and then improve tailpipe emission with meeting stringent emission regulations such as China6b，Euro6d，US Tier3Bin30 and future China7，Euro7. In this paper, we will review our recent engineering work on EHC development associated with hybrid electrical vehicle for better emission control and exhaust aftertreatment.
Lu, Jingwen, Ma, Rongchun, Pan, Lingteng, Dai, Zhengxing, Liu, Yiqiang
Self-Propelled Sweepers Sweep-Ability PerformanceJ1702_202207 (Current)7/26/2022
This SAE Standard establishes a method of disclosing the sweep-ability performance of self-propelled sweepers that use broom means for sweeping and collection, together with either a mechanical- or pneumatic-conveyance system for the transfer of “sweepings” into a collection hopper.
MTC2, Sweeper, Cleaner, and Machinery
The Challenges of Vehicle DecarbonizationEPR2022SE14/27/2022
A narrow focus on electrification and elimination of tailpipe emissions is unlikely to achieve decarbonization objectives. Renewable power generation is unlikely to keep up with increased demand for electricity. A focus on tailpipe emissions ignores the significant particulate pollution that “zero emission” vehicles still cause. It is therefore vital that energy efficiency is improved. Active travel is the key to green economic growth, clean cities, and unlocking the energy saving potential of public transport. The Challenges of Vehicle Decarbonization reviews the urgent need to prioritize active travel infrastructure, create compelling mass-market cycling options, and switch to hybrid powertrains and catenary electrification for long-haul heavy trucks. The report also warns of the potential increase in miles travelled with the advent of personal automated vehicles as well as the pitfalls of fossil-fuel derived hydrogen power. Click here to access the full SAE EDGETM Research Report portfolio.
Muelaner, Jody Emlyn
Laser-Based In-Exhaust Gas Sensor for On-Road Vehicles2022-01-05353/29/2022
A novel laser-absorption gas sensing apparaOn-vehicle Testing at VERtus capable of measuring NO directly within vehicle exhaust was developed and tested. The sensor design was enabled by key advances in the construction of optical probes that are sufficiently compact for deployment in real-world exhaust systems and can survive the harsh, high-temperature, and strongly vibrating environment typical of exhaust streams. Prototype test campaigns were conducted at high-temperature flow facilities intended to simulate exhaust gas conditions and within the exhaust of vehicles mounted on a chassis dynamometer. Results from these tests demonstrated that the sensor prototype is fundamentally free of cross-interference with competing species in the exhaust stream, can achieve a 1 ppmv NO detection limit, and can be operated across the full range of thermodynamic conditions expected for typical vehicle exhausts. These features address the key technological drawbacks associated with electrochemical NOx sensors widely used in current aftertreatment systems while enabling an on-board diagnostic capable of determining NOx output at the tailpipe at a level of accuracy comparable to laboratory-grade instrumentation. Broadly, this novel sensor provides high-quality emissions data needed to help vehicle manufacturers develop powertrains and aftertreatment systems that meet future, more stringent emissions regulations.
Sur, Ritobrata, Peng, Wen Yu, Kempema, Nathan
Identification of Vehicle Noise Based on Transfer Path and Condition Power Spectrum Analysis2022-01-03063/29/2022
The identification of vehicle noise is the basis for studying the acoustic characteristics of vehicles. In this paper, both excitation of noise sources and response of interior noise were identified. Firstly, a transfer path analysis (TPA) model was established to identify the excitation of noise sources, which includes vehicle main noise sources, such as engine, tire, exhaust pipe and muffler. Based on the operational signals and transfer function which were tested in the vehicle semi-anechoic room, the excitation of noise sources was identified using inverse matrix method. Identify result indicated that tires have higher excitation amplitude than engine in high frequency band. Therefore, the transfer path between the tire and the cabin, such as carpet and windshield, should be taken as the focus of acoustic performance improvement. By improving the acoustic material on the transfer path, the loss of sound in the transfer path will be increase. Secondly, the energy superposition method was used to calculate the response of vehicle interior noise based on the established TPA model. In this part, we combine the transfer path analysis and condition power spectrum (CPS) to reduce the correlation among signals. So that we can improve the calculation accuracy of interior noise. The result shows that error between calculated value and test value of interior noise doesn’t exceed 5%, which means the model has a higher identification accuracy for the interior noise. These findings provide important reference value for the improvement of this vehicle’s acoustic performance.
Xing, Yu-Jin, Qu, Zhang, Shangguan, Wen-Bin
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
Evaluation of Optimal State of Charge Planning Using MPC2022-01-07423/29/2022
Hybrid technologies enable the reduction of noxious tailpipe emissions and conformance with ever-decreasing allowable homologation limits. The complexity of the hybrid powertrain technology leads to an energy management problem with multiple energy sinks and sources comprising the system resulting in a high-dimensional time dependent problem for which many solutions have been proposed. Methods that rely on accurate predictions of potential vehicle operations are demonstrably more optimal when compared to rule-based methodology [1]. In this paper, a previously proposed energy management strategy based on an offline optimization using dynamic programming is investigated. This is then coupled with an online model predictive control strategy to follow the predetermined optimal battery state of charge trajectory prescribed by the dynamic program. This work explores the effects of drive cycle segmentation and simplification on the optimality of the results and investigates the effect of reduced prediction accuracy on the optimality of the MPC controller. As the dynamic program relies on future predictions of speed and load, potentially provided from navigation data, the actual drive cycle is likely to vary from the prediction used to perform the offline optimization. The test vehicle modelled in Simulink is a P2 parallel hybrid configuration based on experimental powertrain data. The results of the analysis are then compared to the globally optimal solution using key performance criteria like fuel and energy consumption. Our investigation shows that the energy consumption increase due to poorer prediction accuracy can be up to 19% of the optimal value but also shows that the robustness of the strategy is more acceptable provided certain features of the driveline input can be predicted with a certain degree of accuracy.
Jegede, Temi, Knowles, James, Steffen, Thomas, D'Amato, Marco, Maganga, Othman
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