bluuebunny/crossref_metadata_2025 huggingface dataset:
Disaggregation of PHEV Energy use Under Different Energy Management Strategies
Authors: Campino Miguel , Sousa Luis , Duarte Gonçalo
Published: April 2023

Plug-in hybrid vehicles have complex energy management and are very influenced by charging behavior. Since current on-road data analysis methodologies do not take into consideration propulsion management, it is difficult to correctly estimate their energy and emissions impacts. This paper presents a methodology (ABCD Method) based only on dynamic data to assess the battery state of charge, identifying, second by second, which propulsion source is working and estimating the correspondent energy consumption, pollutant gas emissions and utility factor. Using a Portable Emission Measurement System, this methodology was developed based on real driving data obtained on four trips in two different PHEV. Excellent correlations were obtained between the estimated and measured SOC (R2>0.98). The ABCD Method uses a generic algorithm to allocate points of different propulsion combinations, correctly identifying the energy source used in over 81.9% of trip points. The ABCD method and Vehicle Specific Power (VSP) method were compared with the measurement data from the four trips, indicating that the ABDC method presents in all situations better estimates, except for HC emission, standing out in the estimate of the electric energy use (9.8% ± 6.5% vs 42.1% ± 20.8%, compared with VSP) and utility factor (5.0% ± 3.4% vs 24.7% ± 1.7%). The ABCD method is of major importance for improving the VSP methodology and the current RDE driving data analysis tools used by the European Commission since this method allows knowing which propulsion system is used at each instant.
Measurements of Oil Circulation Rate using Flow-through and Evacuated Type Sampling Cylinders for an Automotive Air Conditioning System
Authors: Haider Syed Angkan , Wang Xin , Elbel Stefan
Published: April 2023

In automotive air conditioning systems, the oil circulation rate (OCR) is known to affect performance at both the component and system levels. The OCR is the ratio of the mass of the oil in a representative sample of oil-refrigerant mixture from the system to the total mass of the sample taken during steady state operation. With the general industry trend towards low-OCR compressors, the OCR values of interest are getting smaller, and it is becoming increasingly important to acquire an accurate knowledge of OCR for proper system optimization. While there are different OCR measurement techniques available, they all require accurate calibration which is done using the ASHRAE Standard 41.4. The standard describes a sampling technique using an evacuated sampling cylinder with a dead end to draw a sample of oil-refrigerant mixture from the system liquid line. The standard, however, doesn’t specify parameters such as sampling cylinder orientation, valve opening speed, etc. which can potentially affect the measured OCR. For the present study, the OCR is measured in an automotive air conditioning facility that uses R-134a as refrigerant and PAG ISO 46 oil as the lubricant for the electric scroll compressor used. OCR results obtained from sampling with both flow-through and evacuated type sampling cylinders are compared at different compressor speeds, and the discrepancies between the results are discussed. For the sampling technique described by the ASHRAE Standard, the OCR is measured with the evacuated sampling cylinder at different orientations and valve opening speeds, and obtained results revealed significant discrepancy between the OCR values. High-speed camera flow visualizations at the evacuated sampling cylinder entrance were also taken, and the observed flows supported the trend in the OCR results.
Reduction of Exposure to Air Pollutants with Map-Based Cabin Air Control
Authors: Borrel Herve , Jung Heejung , Taddonio Paolo
Published: April 2023

More than a hundred million Air Quality Sensors (AQS) have been used since the late 80s to improve in-cabin air quality on high-end cars. This is more than a billion dollars spent. A study conducted in two major cities (USA & Europe) showed that a novel method based on high-resolution air quality maps outperforms the use of on-board AQS. The total passenger exposure to pollution was compared for several flap management algorithm cases: flap always open, random open/close, map-based algorithm, and AQS-based algorithm. The results are likely to disrupt the AQS market since the map-based method is a pure software solution with lower cost per vehicle than the sensor itself. The data volume used to calculate the air quality maps was sufficient to obtain good average correlations between individual trip pollution profiles and the map Air Quality Indices (AQI) along the trip path. To strengthen the correlations and obtain even stronger air quality gains, the data volume can be increased by collecting AQS data from regular vehicles in traffic with an on-board AQS. Collecting AQS data from 50k such vehicles in the USA would be enough to map all US major cities with ample data density. A single OEM could do it. The map-based algorithm could then be implemented on any production car whether it is connected or not. The solution is therefore scalable and will lead to considerable societal benefits in terms of exposure reduction to Mobile Source Air Toxics (MSAT).
Inverse Stiffness Characterization of Electrical Cable and its Importance in Structural Validation
Authors: Thankaraj Rajesh Jeba , Mahadule Roshan , Arul Karthik , M Sivaramprasad
Published: April 2023

An automotive wiring harness is the backbone of the electrical architecture, and it runs throughout the vehicle to transmit electric power. In a virtual simulation, the mechanical properties of individual strands cannot be considered for the harness bundle (or) cable. Predicting the mechanical properties of electrical cables is a challenging task, and it has major setbacks in virtual simulation. This paper proposes an approach to find out the mechanical properties of an electrical cable and explains how the values are used in virtual simulation.

Cable modelling is represented as a lumped mass (or) modelled with a 1D element in the conventional FE modelling approach. In the first part of the study, finite element modelling and material modelling procedures of high and low-voltage electrical cables routed through brackets and troughs are discussed. Mechanical properties are developed using an inverse stiffness characterization method from bench level physical testing in static and dynamic conditions. The physical setup is replicated in a virtual simulation. The material properties used in simulation are iterated until the results match the physical testing results.

Material properties derived from the inverse stiffness approach are tested with various applications, and it gives promising agreement in correlation and prediction with physical test results. A Test Vs CAE correlation exercise has been performed for various problems like random vibration analysis, mechanical shock test, and engine roll simulation. The main objective of the paper is to present a suitable material calculation method for electric cables that encounter structural problems in static and dynamic conditions. The test-based inverse stiffness characterization method is observed as an efficient method for the finite element material modelling of cables. Adopting the proposed method, high manual effort and computation time involved in micro-level modelling of cables can be avoided.
Vibration Dose Value (VDV) and A (8) Calculation in Electric Two-Wheeler Using CAE Methodology with Test Correlation
Authors: S Vishnu , Holla Muralidhara , B G Puneeth Kumar , B S Abhishek , M Manish , R Dinesh , U Manjunatha , Mallick Bikash
Published: April 2023

A typical motorcyclist experiences different vibration transfer functions at the point of body-vehicle interaction while riding. The main sources of vibration are engine-induced vibrations (for internal combustion engines), motor-induced vibrations (for electric vehicles), and road-induced vibrations. These vibrations can be perceived as criteria for driving comfort or as that is undesirably irritating and physically affecting the human body in various ride scenarios. Vibration Dose Value (VDV), Exposure Action Value (EAV), Exposure Limit Value (ELV) and RMS acceleration-A (8) Values are key metrics for accessing a perception of overall level of vibration transfer to the human body during various vibration exposures. The purpose of this study is to develop and propose a simulation method to calculate the VDV and A (8) values using a full vehicle CAE/FE simulation-based approach. The aim is to reduce the lengthy and tedious serial tests during the various course of a vehicle product development. As part of this research validation study, correlations with conventional test methods have also been performed to establish a well acceptance criteria for the simulation-driven approach. In this study, the vibration acceptance values are evaluated on an electric two-wheeled scooter as a function of the road roughness index and the electric motor flux forces. Good correlations were found between simulation and test-based approaches.
On the Development of CFD Methodology for Free-Falling Varnish Stream Modeling to Support EV Motor Manufacturing
Authors: Jan James , Petersen Ben , Huang Xionghui , Vijayan Ajaicimhan , Li Jun
Published: April 2023

When manufacturing the stators in EV motors, stator wires are first coated with a layer of resin to provide primary insulation. After winding, impregnating varnish fills all voids within the windings and between the windings and lamination. In addition to electrically insulating the copper wires, another function of the varnish fill is to mechanically secure the copper wires from movement. The process is not complicated in terms of physics. In essence, the mechanics of the varnish flow is the balance of inertia force, viscous force, gravity and surface tension. However, understanding the fluid dynamics of the varnish flow is critical to predicting the quality of the varnish fill, which has a tremendous impact on motor performance. With the advancement of computational fluid dynamics (CFD), the industry can benefit greatly if the varnish trickling process can be tuned, without physical tryouts, to achieve optimal fill. The intent of this research is to develop the computational methodology to study the varnish flow, so that its flow pattern can be simulated and predicted in the varnish trickling process. Because varnish flow by nature is a two-phase flow, special attention is needed to treat the large density difference between air and varnish, as well as the surface tension acting on the phase boundary. Furthermore, the well-known Plateau-Rayleigh instability associated with free-falling streams poses great challenges to the numerical method. In this research, two distinctive computational methodologies, FVM (Finite Volume Method) and SPH (Smoothed-Particle Hydrodynamics), are utilized to model the varnish free-falling streams. The end results are compared with analytical solutions and experimental observations to verify their accuracy. Also included is the comparison of numerical artifacts introduced by the two CFD methods. Another valuable achievement is the utilization of experimental results to reduce the costly computation time for reaching steady-state solution.
Conducting Comparisons of Multi-Body Dynamics Solvers with a Goal of Establishing Future Direction
Authors: Renaud Raymond , Schudt Joseph , Vilela Daniel
Published: April 2023

As passenger vehicle design evolves and accelerates, the use of multi-body dynamics solvers has proven to be invaluable in the engineering workflow. MBD solvers allow engineers to build virtual vehicle models that can accurately simulate vehicle responses and calculate internal forces, which previously could only be assessed using physical prototype builds with hundreds of measurement transducers.

Evaluation and selection of solvers within an engineering environment is inherently a multi-dimensional activity that can include ease of use, retention of previously developed expertise, accuracy, speed, and integration with existing analysis processes. We discuss here some of the challenges present in developing capability and accumulating data to support each of these criteria. Developing a pilot model that is capable of being applied to a comprehensive set of use cases, and then verifying those use cases, required significant project management activity. Comparisons were conducted within existing tool chains for capability verification. The highly integrated nature of multi-body dynamics tools encourages collaboration with the solver vendor during the evaluation period. We ultimately considered our evaluation to be successful, thus providing valuable insights into the advantages and disadvantages of the solvers under investigation.
Identification of Swing Gate Seal Chucking using Predictive Methodologies and Test Correlation
Authors: Mohammed Riyazuddin , C M Mithun , Raghavendran Prasath
Published: April 2023

For decades, customer complaints on Squeak & Rattle issues have come as a question of quality for the automotive industry. Squeak and rattle sounds are customer irritants due to their non-patterned and transient nature. Squeak is a friction induced noise that generally occurs because of rubbing of the two materials that are incompatible with each other. While rattle is a phenomenon that occurs due to the impact between the two parts having unintended gap. They are no more secondary noises and avoiding or elimination of these become significant for brand building and warranty cost reduction. Chucking is a form of squeak noise that occurs due to the interaction between uncoated seal to seal. In Swing gate, this phenomenon is seen when seal bulb inner layers are completely compressed. Swing gate have fore-aft modes that are excited due to dynamic responses from different road profiles. Traditional find and fix approach is time consuming and to reduce product development time, CAE methodologies are explored. This paper attempts to discuss about seal chucking in swing gate and its degradation. An implementable process in predicting the seal chucking during design phase is presented. Simulation studies were carried out by varying the seal stiffness and positioning the features like bump stop. The proposed method was effective in reduction of seal chucking. Physical measurements confirmed the reduction in relative motion with the proposed manufacturable solution. The test findings were in line with the CAE analysis. Recommendations for future swing gate design will be presented.
Switchable Control Strategy Study of a Novel Multi-function Electromagnetic Damper Based on Road Classification
Authors: Xia Xiangjun , Ning Donghong , Liao Yulin , Liu Pengfei , Du Haiping
Published: April 2023

Electromagnetic damper (EMD), which has shown good vibration isolation and energy harvesting potential, has received much attention in recent years. In addition, the harvested energy of EMD systems can be used to further suppress severe vibration. When the harvested energy of the suspension system is more than the consumed energy, the suspension system can realize self-powered functions. However, the integration of the above three functions is a challenge for the design of EMD systems. In this paper, a novel multi-function electromagnetic damper (MFEMD) system, which integrates the semi-active vibration control mode, energy-harvesting mode, and self-powered mode, is introduced first. The MFEIS system applies an H-bridge circuit to control the multi-directional flow of circuit energy flow, and the supercapacitor is used as the energy storage device because of its high-power density and rapid response speed. Since vehicles are driving in complex road conditions in the real world, road information needs to be considered to control the MFEMD system. Additionally, the energy recovery efficiency and vibration suppression performance of the MFEMD system also need to be balanced. A switchable control strategy based on road classification is proposed to switch the state of the MFEMD system. According to the real driving conditions, roads are classified into three categories, namely high-speed smooth roads, medium-speed good roads, and low-speed bad roads. The state of the MFEMD system is switched based on the road information to balance the ride comfort and energy recovery efficiency. A complex road, which contains different levels of random roads, is adopted to verify the effectiveness of the proposed control strategy. Simulation results verified the effectiveness of the proposed switchable control strategy compared with a well-tuned passive suspension and a semi-active suspension.
Heat Transfer Correction Model for Turbocharger Compressor Performance Maps
Authors: Usai Vittorio , Marelli Silvia , Cordalonga Carla
Published: April 2023

Turbochargers are still one of the most common solutions to improve internal combustion engines performance. The correct evaluation of turbochargers characteristic maps is one of the main issues to achieve a good matching with internal combustion engines. In a 1D procedure the accuracy of performance maps constitutes the basis of the turbocharger matching with the engine. The classical quasi-steady approach assumes that compressor and turbine characteristic maps are evaluated under the hypothesis of adiabatic turbocharger behavior. The aim of the paper is the investigation of the effect of heat transfer phenomena on the measured turbocharger maps. A model to correct compressor efficiency evaluated starting from measured data, thus removing the heat transfer effects, is proposed. The compressor steady flow behavior has been analyzed through specific tests performed at the test rig for components of propulsion systems of the University of Genoa, under various heat transfer conditions. The experimental campaign was conducted on a water-cooled turbocharger for spark ignition engines and on an uncooled turbocharger for diesel engines considering the effect of different heat transfer conditions. Then, measurements were carried out under quasi-adiabatic conditions, maintaining a constant temperature between the compressor - intermediate casing - turbine to validate the proposed model. Thanks to this specific campaign it was possible to validate the proposed model highlighting a high degree of accuracy. The main advantage of the method presented here compared to others developed by the authors or found in the open literature is its ease of use, thus requiring a small amount of geometric and physical information that can be obtained in a standard turbocharger test bench.
Extension and Validation of a Constant Equivalence Ratio Multi-Zone Approach to DME Combustion in Vessels and CI Engines
Authors: Ballerini Alberto , D'Errico Gianluca , Onorati Angelo , Tamborski Matteo
Published: April 2023

This work has the objective to present the extension of a novel quasi-dimensional model, developed to simulate the combustion process in diesel Compression Ignition (CI) engines, to describe this process when Dimethyl ether (DME) is used as fuel. DME is a promising fuel in heavy-duty CI engines application thanks to its high Cetane Number (CN), volatility, high reactivity, almost smokeless combustion, lower CO2 emission and the possibility to be produced with renewable energy sources. In this paper, a brief description of the thermodynamic model will be presented, with particular attention to the implementation of the Tabulated Kinetic Ignition (TKI) model, and how the various models interact to simulate the combustion process. The model has been validated against experimental data derived from constant-volume DME combustion, in this case the most important parameters analyzed and compared were the Ignition Delay (ID) and Flame Lift Off Length (FLOL). Following this first validation process, the model has been tested against experimental values obtained from a heavy-duty DME-fueled CI engine in different operating conditions, representative of real engine applications. In this second comparison, the focus shifted on Heat Release Rate (HRR) and in-cylinder pressure trends and NOx production during combustion. The results show good agreement between the experimental and computed values in all operating conditions, leading to the possibility of using the presented model to accurately predict the performance of engines with DME as fuel in a fast 1D- or quasi-dimensional simulation tool.
A Conjugate Heat Transfer Analysis of a Rotary Combustion Engine with a Focus on the Effect of Thermal Barrier Coatings
Authors: Pisnoy Shimon , Frankel Steven , Tartakovsky Leonid
Published: April 2023

In recent years, rotary combustion engines have experienced renewed interest as alternative power sources in various applications, due to their multi-fuel capability, simplicity, and advantageous power-to-weight, and power-to-volume ratios. Further improvements to the engine's performance require a thorough examination of its inherent shortcomings. Most prominent are its incomplete, slow combustion and lower thermal efficiency, both of which are caused by the combustion chamber's high surface-to-volume ratio and unfavorable flattened shape. Considering the difficulties involved in performing experimental measurements on rotary combustion engines, numerical simulations have proven to be valuable tools for research and development. This study presents a validated three-dimensional RANS model that simulates the flow, reaction kinetics, and heat transfer in rotary combustion engines. The model incorporates a conjugate heat transfer approach, which couples the heat transfer between the solid rotor, the convective airflow within its core, and the gas in the combustion chamber. Different heat transfer models and meshing approaches were evaluated as part of the development of the model for high load/high revving speed applications. Lastly, an advanced thermal barrier coating was proposed for use in rotary combustion engines. The developed model was modified to include a temperature discontinuity at the solid-gas interfaces of the rotor, which is related to the thermal resistivity of the coating. It was predicted that the application of the coating would reduce heat losses by 10 %, lower the mean temperature of the rotor by 4.6 %, and improve the fuel conversion efficiency by 1.3 %. The results suggest that an advanced thermal barrier coating can reduce thermal loads and enhance the performance of rotary combustion engines.
Minimizing Steady-State Testing Time in an Engine Dynamometer Laboratory
Authors: DeCoste Steven , Scalzi Antonio , Chen Jun , DelVescovo Dan
Published: April 2023

In the automotive industry, performing steady-state tests on an internal combustion engine can be a time consuming and costly process, but it is necessary to ensure the engine meets performance and emissions criteria set by the manufacturer and regulatory agencies. Any measures that can reduce the amount of time required to complete these testing campaigns provides significant benefits to manufacturers. The purpose of this work is then to develop a systematic approach to minimize the time required to conduct a steady-state engine test campaign using a Savitsky-Golay filter to calculate measured signal gradients for continuous steady-state detection. Experiments were conducted on an Armfield CM11-MKII Gasoline Engine test bench equipped with a 1.2L 3-cylinder Volkswagen EA111 R3 engine. The test bench utilizes throttle position control and an eddy current dynamometer braking system with automatic PID control of engine speed. Data from engine signals (e.g. exhaust temperature, engine speed, air-fuel ratio etc.) were continuously collected, allowing for detection of steady-state and further analysis in post-processing.

In this preliminary work, two distinct approaches were studied for generating a map of engine data in the typical load/speed operating space: 1) a constant-speed variable-throttle/load sweep, and 2) a constant-throttle variable-speed sweep. Both test approaches were equally capable of generating the desired engine operating map, but using the second approach, i.e., the constant-throttle sweep, saved an average of 41 seconds per operating point, representing a 15% reduction in total time to steady-state for the operating points tested. This reduction was due to the decrease in exhaust temperature change between engine operating points associated with changes in engine speed as opposed to changes in engine load, as well as the improved dynamic response in engine speed of the eddy current dynamometer braking system.
Multi-Plane PIV using Depth of Field for In-cylinder Flow Measurements
Authors: Willman Christopher , He Qichi , Williams Benjamin A. O. , Stone Richard , McAllister Matthew
Published: April 2023

Extending the planar Particle Image Velocimetry (PIV) technique to enable measurements on multiple planes simultaneously allows for some of the 3 dimensional nature of unsteady flow fields to be investigated. This requires less hardware and retains the typically higher spatial resolution of planar PIV compared to fully 3-dimensional PIV techniques. Performing multi-plane PIV measurements requires the light scattered from the different measurement planes to be distinguishable. This may be achieved by using different laser wavelengths which adds significantly to the expense and complexity of the system, by using different light sheet polarisations which is challenging for engine measurements through windows due to stress-induced birefringence, or by making alternating measurements of each plane which sacrifices the simultaneity of the flow measurement across multiple planes. In this work, simultaneous PIV measurements on two parallel offset planes are performed by modifying a standard two-dimensional two-component (2D2C) PIV system consisting of a single high-speed camera and a dual-cavity PIV laser. Image splitting optics with a variable optical path length were used to image two measurement planes onto the single camera sensor. The degree of defocus of the droplet images arising from the narrow depth of field was used to distinguish between the measurement planes. The robustness of the degree of defocus method for plane discrimination was evaluated using both representative test targets and experimentally obtained PIV images of the in-cylinder flow field of a spark ignition internal combustion engine (ICE). This depth of field based method enables simultaneous multi-plane PIV measurements of in-cylinder flows to be performed with only minor alterations to a standard 2D2C PIV system using off-the-shelf optics.
Flexible Architecture for Testing Connected Vehicles in Realistic Traffic
Authors: Buller William , Chase Richard , Paki Joseph E. , Dudekula Ahammad Basha , Naber Jeffrey , Sarkar Reuben
Published: April 2023

Connected vehicles have the potential to transform the way we commute and travel in a multitude of ways. Vehicles will cooperate and coordinate with each other to solve problems appropriate for the environment in which they are operating. In this paper, we focus on the development of test equipment that includes the infrastructure and vehicles to measure and record all of the information necessary to quantify the performance of cooperative driving algorithms in realistic scenarios. The system allows tests to include real vehicles on the track and virtual vehicles in a digital twin. Real and virtual vehicles interact through the road-side units and test facility network, allowing each test vehicle to receive messages from virtual vehicles as well as the infrastructure. Messages transmitted from the test vehicles are received in the digital twin, allowing the real vehicle to interact with virtual vehicles. This provides the capability to test algorithms in congested traffic without the expense and risk of conducting tests with many cars. The system is shown to allow for real-time operation of connected vehicles in closed loop operation using industry standard networks, along with a protocol for centralized traffic management, which is not currently standardized. Tests have been performed at highway speeds. The architecture has a low barrier to entry application programming interface for its vehicle to infrastructure network that utilizes the Robotic Operating System interface. The paper describes the development and integration of components and protocols, characterization of the network performance, methods for recording data referenced to a single clock, and demonstration of the repeatability of measurements made on test vehicles. The discussion at the end of the paper looks at current research on the impact of cooperative driving algorithms on energy efficiency and traffic flow.
Optimizing Spark Assisted GCI Combustion with the Compression Ratio and Internal Exhaust Gas Recirculation (I-EGR) Strategies
Authors: Raman Vallinayagam , Viollet Yoann , Chang Junseok
Published: April 2023

The combustion instability at low loads is one of the key technology risks that needs to be addressed with the development of gasoline compression ignition (GCI) engine. The misfires and partial burns due to combustion instability leads to excessive hydrocarbon (HC) and carbon monoxide (CO) emissions. This study aims to improve the combustion robustness and reduce the emissions at low loads. The GCI engine used in this study has unique hardware features of a spark plug placed adjacent to the centrally mounted gasoline direct injector and a shallow pent roof combustion chamber coupled with a bowl in piston geometry. The engine experiments were performed in a single cylinder GCI engine at 3 bar indicated mean effective pressure (IMEP) and 1500 rpm for certified gasoline with research octane number (RON) = 91. Enabling strategies such as internal exhaust gas recirculation (i-EGR), compression ratio (CR = 16 & 18) and spark assisted ignition were investigated to improve the combustion robustness. Several other control variables such as intake temperature, intake pressure, fuel injection pressure, fuel injection timing, and exhaust back pressure were used to optimize the operation under low load conditions.

The experimental study revealed that exhaust rebreathing supports the combustion stability but with the difficulty of precise back pressure control. For CR = 16 piston, exhaust re-breathing (i-EGR) combined with spark assistance enables to achieve a coefficient of variation (COV) below 2% with NOX emission of around 0.1 g/kWh. At higher CR = 18, pressure and temperature conditions are favorable to support the auto-ignition driven combustion without exhaust rebreathing. For improved combustion stability, spark assistance is needed with CR = 18 piston. Optimum spark shortened the burn rate, improved the combustion stability, and reduced the HC emissions. The effects of the flame initiated by the spark plug on the overall combustion is limited to the vicinity of spark arc. Overall, when fuel mixture is stratified under partially premixed compression ignition (PPCI) conditions, spark is needed to strengthen the ignition behavior without disturbing the major auto-ignition combustion behavior.
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 Standards
Authors: Xu Lifeng , Zhao Fucheng , Wei Hong , Zhao Pengfei , Qian Wangmu , Qian Menghan
Published: April 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.
Optical Investigation of Mixture Formation in a Hydrogen-Fueled Heavy-Duty Engine with Direct-Injection
Authors: Laichter Judith , Kaiser Sebastian A. , Rajasegar Rajavasanth , Srna Ales
Published: April 2023

Mixture formation in a hydrogen-fueled heavy-duty engine with direct injection and a nearly-quiescent top-hat combustion chamber was investigated using laser-induced fluorescence imaging, with 1,4-difluorobenzene serving as a fluorescent tracer seeded into hydrogen. The engine was motored at 1200 rpm, 1.0 bar intake pressure, and 335 K intake temperature. An outward opening medium-pressure hollow-cone injector was operated at two different injection pressures and five different injection timings from early injection during the intake stroke to late injection towards the end of compression stroke. Fuel fumigation upstream of the intake provided a well-mixed reference case for image calibration. This paper presents the evolution of in-cylinder equivalence ratio distribution evaluated during the injection event itself for the cylinder-axis plane and during the compression stroke at different positions of the light sheet within the swirl plane. During the injection event, the originally annular jet collapses onto the jet axis within 1°CA after jet emergence and within 10 mm downstream of the nozzle. Multiple shock cells are visible – their size decreases with decreasing pressure ratio. The results of the equivalence ratio distribution show high cyclic variability of mixing for all injection timings during the compression stroke, but only minor variability with early injection during the intake stroke. The ensemble-mean fuel distribution shows that fuel-rich zones shift from the intake side to the exhaust side of the combustion chamber as the injection is advanced. Probability density functions of global equivalence ratio and equivalence ratio at potential spark locations suggest that retarded fuel injection might significantly increase NO emissions and the cyclic variability of early flame kernel development.
Emission Characteristics of a Light Diesel Engine with PNA under Different Coupling Modes of EHC and Aftertreatment System
Authors: Kang Lulu , Fang Liang , Zhao Yunkun , Lou Diming , Zhang Yunhua , Luo Chagen
Published: April 2023

With the continuous upgrading of emission regulations, NOx emission limit is becoming more and more strict, especially in the cold start phase. Passive NOx absorber (PNA) can adsorb NOx at a relatively low exhaust temperature, electrically heated catalyst (EHC) has great potential to improve exhaust gas temperature and reduce pollutant emissions of diesel engines at cold start conditions, while experimental research on the combined use of these two kinds of catalysts and the coupling mode of the electrically heated catalyst and the aftertreatment system under the cold start condition are lacking. In this paper, under a certain cold start and medium-high temperature phase, the exhaust gas temperature and emission characteristics of PNA, EHC and aftertreatment system under different coupling modes were studied. Results showed that the average inlet temperature of diesel oxidation catalyst (DOC) and selective catalytic reduction catalyst (SCR) integrated into diesel particulate filter (SDPF) increased by 246.35 ℃ and 126.09 ℃ respectively under the coupling mode of PNA+EHC+DOC+ SDPF+SCR during cold start phase. The inlet temperature of DOC was not affected, and the average inlet temperature of SDPF increased by 200.52 ℃ under the coupling mode of PNA+DOC+EHC+SDPF+SCR. In terms of emissions, the effective NOx adsorption range of PNA reached more than 140s under the two coupling modes. During cold start phase, under the coupling mode of PNA+EHC+DOC+SDPF+SCR, the conversion efficiencies of carbon monoxide (CO), total hydrocarbons (THC) and nitrogen oxides (NOx) were 97.58%, 94.62% and 78.81% respectively, compared with EHC off, it had increased by 55.84%, 55.84% and 55.84% respectively. Under the coupling mode of PNA+DOC+EHC+SDPF+SCR, the conversion efficiencies of CO, THC and NOx were 58.68%, 87.50% and 95.42% respectively, compared with EHC off, it had increased by 15.91%, 11.70% and 51.41% respectively. EHC coupled front DOC was more conducive to CO and THC emission control, and EHC coupled rear DOC was more conducive to NOx emission control. The SDPF pressure drop corresponding to EHC coupled front DOC was greater than that of EHC coupled rear DOC, the PN conversion efficiency of EHC coupled front or rear DOC was more than 99%.
Analysis of Combustion Cycle-to-Cycle Variation in an Optical Single Cylinder Dual-Fuel Engine
Authors: Lauterkorn Alexander Michael , Wang Xinyan , Zhao Hua
Published: April 2023

This study aims to improve the dual fuel combustion for low/zero carbon fuels. Seven cases were tested in a single cylinder optical engine and their ignition and combustion characteristics are compared. The baseline case is the conventional diesel combustion. Four cases are diesel-gas (compressed natural gas) dual-fuel combustion operations, and two cases are diesel-hythane combustion. The diesel fuel injection process was visualized by a high-speed copper vapour laser. The combustion processes were recorded with a high-speed camera at 10000 Hz with an engine speed of 1200 rpm. The high-speed recordings for each case included 22 engine cycles and were postprocessed to create one spatial overlapped average combustion image. The average combustion cycle images were then further thresholded and these images were then used in a new method to analyze the cycle-to-cycle variation in a dimensionless, for all cases comparable value. Furthermore, the ignition delay and heat release profile of each case are analyzed. The results showed the lowest deviation from the complete overlap for the pure Diesel case and the Hythane Cases since the flames are more concentrated in these. From these studies, it can be concluded that the cyclic variation for the pure diesel combustion is mostly caused by the different swirl speeds in the piston bowl. The diesel-gas dual-fuel combustion with earlier pilot injections have lower cyclic variation due to a wider spread of the combustible mixture. The usage of hythane as main fuel instead of methane results in a about 10% faster combustion and more concentrated flames areas.
Potential of Di-Ethyl Ether in Reducing Emissions from Heavy-Duty Tractors
Authors: Kalwar Ankur , Singh Akhilendra , Agarwal Avinash Kumar
Published: April 2023

Considering the demand for sustainable transport, alternative fuels are a keen research topic for IC engine researchers. Among various alternative fuels being explored, Di-ethyl ether (DEE) is gaining popularity off-late for compression-ignition (CI) engines owing to its high cetane rating, oxygen presence in its molecular structure, and lower carbon content. This study explores the suitability of DEE blends in tractor engines. DEE blends [15% and 30% (v/v)] with diesel were compared with baseline diesel for combustion, and emission characterisation, keeping all parameters identical, including the fuel injection timings. Results were analysed for different engine loads at 1500 rpm. Delayed combustion was observed with DEE blends with diesel, possibly due to a higher cooling effect from DEE vaporisation and retarded dynamic fuel injection due to its higher compressibility. However, the DEE blend fuelled engine performance was comparable to baseline diesel. Considerable reductions in NOx and soot emissions were observed with DEE30. Hence, compared to DEE15, DEE30 emerged as a more suitable fuel for heavy-duty tractor engines using a mechanical fuel injection system, exhibiting lower emissions and comparable efficiencies.
Active Plasma Probing for Lean Burn Flame Detection
Authors: Wang Linyan , Yu Xiao , Cong Binghao , Li Liguang , Chen Guangyun , Zheng Ming
Published: April 2023

Combustion diagnostics of highly diluted mixtures are essential for the estimation of the combustion quality, and control of combustion timing in advanced combustion systems. In this paper, a novel fast response flame detection technique based on active plasma is introduced and investigated. Different from the conventional ion current sensing used in internal combustion engines, a separate electrode gap is used in the detecting probing. Further, the detecting voltage across the electrode gap is modulated actively using a multi-coil system to be slightly below the breakdown threshold before flame arrival. Once the flame front arrives at the probe, the ions on the flame front tend to decrease the breakdown voltage threshold and trigger a breakdown event. Simultaneous electrical and optical measurements are employed to investigate the flame detecting efficacy via active plasma probing under both quiescent and flow conditions. The RT-FPGA system provides flexible, prompt, and precise control for the detecting frequency to analyze the overall flame propagation process. Two types of fuels are used in the study, including methane, and DME, with an air-fuel ratio sweep from stoichiometric to extremely lean. Efforts are made to characterize the criteria of minimum, yet adequate voltage to succeed in the detection of the flame front arrival. For comparison, conventional ion current measurements are conducted under identical testing conditions. Results show that the active plasma probing has benefits in detecting the flame arrival robustly for lean combustion under both quiescent and turbulent flow conditions. Under lean combustion, the intensity of ion current signal is significantly suppressed and signal rise time is prolonged due to the lower flame temperature. The active plasma probing provides a detecting response approximately one hundred times faster compared with the conventional ion current sensing, which shows potential for more effective real-time combustion control.
Diesel Particulate Filter Durability Performance Comparison Using Metals Doped B20 vs. Conventional Diesel Part I: Accelerated Ash Loading and DPF Performance Evaluation
Authors: Lakkireddy Venkata , McCormick Robert L. , Weber Phillip , Howell Steve
Published: April 2023

The project objective was to generate experimental data to evaluate the impact of metals doped B20 on DPF ash loading and performance compared to that of conventional petrodiesel. Accelerated ash loading was conducted on two DPFs – one exposed to regular diesel fuel and the other to B20 containing metal dopants equivalent to 4 ppm B100 total metals (currently total metals are limited to 10 ppm in ASTM D6751, the standard for B100). Periodic performance evaluations were conducted on the DPFs at 10 g/L ash loading intervals. After the evaluations at 30 g/L, the DPF was cleaned with a commercial DPF cleaning machine and another round of DPF evaluations were conducted. A comparison of the effect of ash loading with the two fuels and DPF cleaning is presented. The metals doped B20 fuel resulted in ash that was similar to that deposited when exposed to ULSD (lube oil ash) and exhibited similar ash cleaning removal efficiency. Metals doped B20 resulted in faster ash accumulation within the DPF, as expected, but did not appear to have a negative effect on DPF pressure drop or regeneration rates (up to 30 g/L of ash) or exhibit deleterious physical effects on the DPF substrate.
Experimental and Numerical Study of Water Injection under Gasoline Direct Injection Engine Relevant Conditions
Authors: Zhai Jiachen , Miganakallu Narasimhamurthy Niranjan , Naber Jeffrey , Lee Seong-Young
Published: April 2023

Water injection has been used to reduce the charge temperature and mitigate knocking due to its higher latent heat of vaporization compared to gasoline fuel. When water is injected into the intake manifold or into the cylinder, it evaporates by absorbing heat energy from the surrounding and results in charge cooling. However, the effect of detailed evaporation process on the combustion characteristics under gasoline direct injection relevant conditions still needs to be investigated. Therefore, spray study was firstly conducted using a multi-hole injector by injecting pure water and water-methanol mixture into constant volume combustion chamber (CVCC) at naturally aspirated and boosted engine conditions. The target water-fuel ratio was fixed at 0.5. Mie-scattering and schlieren images of sprays were analyzed to study spray characteristics, and evaluate the amount of water vaporization. The qualitative analysis of the water and water-methanol sprays demonstrated the inability of water to evaporate completely. Moreover, simulations of water spray injection were also performed under the framework of CONVERGE using the Eulerian-Lagrangian modeling approach. The amount of vaporized water, evaporation rate, temperature evolution, saturation ratio was analyzed and compared under different crank angles. The presented simulation scheme will provide informative support for the future design of water injection pattern in internal combustion engines.
Performance and Emission Characteristics of Direct Injection DME Combustion under Low NOx Emissions
Authors: Leblanc Simon , M Murugesa Pandian , Han Xiaoye , Tjong Jimi , Zheng Ming
Published: April 2023

Compression ignition internal combustion engines provide unmatched power density levels, making them suitable for numerous applications including heavy-duty freight trucks, marine shipping, and off-road construction vehicles. Fossil-derived diesel fuel has dominated the energy source for CI engines over the last century. To mitigate the dependency on fossil fuels and lessen anthropogenic carbon released into the atmosphere within the transportation sector, it is critical to establish a fuel source which is produced from renewable energy sources, all the while matching the high-power density demands of various applications. Dimethyl ether (DME) has been used in non-combustion applications for several decades and is an attractive fuel for CI engines because of its high reactivity, superior volatility to diesel, and low soot tendency. A range of feedstock sources can produce DME via the catalysis of syngas.

In this work, DME is applied in a direct injection compression ignition combustion application. A novel plunger-type injection system was used to pressurize DME to 415 bar. Each set of operating conditions was subject to exhaust gas dilution to lower NOx emissions below the current regulatory standards. The results focused on the combustion characteristics and exhaust emissions, with matching conditions under diesel-fueled operation as a baseline reference for proper comparison. Non-regulated exhaust species were compared, specifically hydrogen, methane, and formaldehyde. The ultra-low smoke characteristic of DME avoided the classical NOx-soot trade-off of diesel-fueled engines, allowing for combustion optimization through stronger exhaust gas dilution. DME showed improved combustion completeness likely owing to the self-containing oxygen and higher volatility minimizing the dependency on mixing with the in-cylinder surrounding compressed charge.