Similar Journals
|
Automotive and Engine Technology
Number of Followers: 0  Hybrid journal (It can contain Open Access articles)ISSN (Print) 2365-5127 - ISSN (Online) 2365-5135 Published by Springer-Verlag  [2468 journals]
|
- Effect of flexible camshaft technology on dual-fuel engine performance
using phenomenological combustion model-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract The objective of the current study is to investigate the effect of tunable valve timings on the performance and emissions of a dual-fuel marine engine. A simulation model was developed in MATLAB to simulate the valvetrain mechanism. The model generates different valve lift curves depending on the input conditions, and after that, it tests them against any possible collision with the piston. The valid valve lift curves were exported to a two-zone combustion model in AVL CRUISE-M platform. The combustion model depends on the fractal principle and aims to predict the in-cylinder parameters. In addition, it contains sub-models to calculate the ignition delay and emissions formation. Model results were compared against experimental data, as the latter were obtained from a heavy-duty, medium-speed, single-cylinder research engine, which employs natural gas as a main fuel. The results showed good agreement and the model was used for further investigations with other cam pairs. It has been found that the fractal combustion model can effectively represent the combustion behavior in the dual-fuel engine. Furthermore, valve timing has a significant influence on the engine performance and exhaust emissions. Results also revealed that applying Miller cycle can reduce the nitrogen oxides emissions, while the higher valve overlap period had a negative effect on methane slip.
PubDate: 2023-11-08
-
- Approaches for automated wiring harness manufacturing: function
integration with additive manufacturing-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract With the electrification of powertrains and the progressive implementation of assisted and automated driving functions, the vehicle wiring harness is becoming increasingly important in the automotive industry. The design of the wiring harness is gaining considerable variation and is becoming more and more complex. In order to master this complexity in the manufacturing processes in a reliable manner, new approaches are required for the progressive automation of the wiring harness production. Additive manufacturing processes have not yet been used in the production of vehicle wiring harnesses. The development of additive processing of conductive materials therefore creates a new basis for the development of automation solutions to produce vehicle wiring harnesses. With the approach of function-integrated multi-material application, the possibility of using electrically conductive polymers in the vehicle wiring harness is specified in detail. A fundamental study was carried out to determine the values of electrical conductivity that can be achieved in the field of plastics. Based on these findings, the research question being addressed is whether polymers can be made electrically conductive to an extent that is suitable for use in a vehicle’s wiring harness. The materials of electrically conductive components from conventional vehicle electrical systems serve as a reference. A specially developed test set-up for measuring the electrical conductivity of polymers provided the required measured values. The quantitative evaluation of the measurements clearly shows that the use of conductive polymers as a conductive material in the vehicle wiring harness is only possible to a limited extent. The major benefit of the study identified the use of electrically conductive polymers for the automatable production of electrical connections.
PubDate: 2023-08-13
DOI: 10.1007/s41104-023-00137-9
-
- Development of an ejector for passive hydrogen recirculation in PEM fuel
cell systems by applying 2D CFD simulation-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract The anode subsystem is a major energy consumer of polymer-electrolyte-membrane (PEM) fuel cell systems. A passive hydrogen recirculation system, like an ejector, is an excellent solution to maximize hydrogen utilization while maintaining low parasitic losses. However, high development efforts are necessary to maximize the performance of the ejector for the entire operating range. This research paper provides part of a toolchain for ejector development, consisting in particular of a multi-parameter simulation based on rotational symmetric 2D CFD. The 2D CFD greatly helps optimize the design of the ejector, reducing development effort, and increasing accuracy. In addition, the main correlations between thermodynamic states and geometry on the entrainment ratio are evaluated. Subsequently, an ejector is designed for a PEM fuel cell application using 2D CFD and the results show in which operating range a single ejector can be applied. This toolchain enables rapid design and optimization of ejector geometry, saving development time and cost while increasing accuracy and extending the operating range.
PubDate: 2023-07-31
DOI: 10.1007/s41104-023-00133-z
-
- Optical spray investigations and 3D-CFD numerical analysis of the nozzle
flow of a methanol HPDI injector for maritime applications-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract This article presents results of the optical spray investigations of a methanol high-pressure direct injector for maritime applications. The injector is a two-in-one fuels injector, with a diesel path to inject diesel centrally for the diesel mode or to inject a small pilot amount of diesel for igniting methanol. The methanol will be injected via three nozzles, which are placed around the central diesel needle. The experimental studies were performed at a pressurized injection chamber with three different injection pressures, two fuels and three nozzle designs to evaluate first the basic spray characteristics of the spray of this two-in-one fuel’s injector concept with four needles as well as the impacts of the varied parameters. For the injection analysis, ethanol was used instead of methanol due to the extensive safety requirements for methanol. Furthermore, a 3D-CFD numerical analysis of the nozzle flow of the methanol path is presented in this article. Correlations between the calculated nozzle flow and the experimental measured spray data are given.
PubDate: 2023-07-25
DOI: 10.1007/s41104-023-00135-x
-
- An experimental study on aging effects of the air–fuel ratio swing on
modern gasoline three-way catalysts-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Today’s governmental legislations require region specific emission standards for passenger vehicles. Continuously increasing legal requirements demand the development of more complex exhaust gas after treatment systems to further reduce harmful gases like carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NOx). Due to specific load profiles and other boundary conditions, the efficiency of the aftertreatment system declines over lifecycle, so that the emissions might increase. Consequently, the durability of the system becomes a critical design parameter with upcoming legislation demanding emissions stability over the vehicle life cycle. Within this publication, catalyst aging effects due to air–fuel ratio (AFR) swing are analyzed experimentally. To create catalyst aging conditions, a modern eight-cylinder turbocharged engine was modified and specific aging cycles with a variation of AFR swing amplitude and frequency were conducted. Light-off curves were used to depict the negative impact of the AFR swing on the aging catalyst systems. A higher swing frequency resulted in an increased temperature amplitude within the entrance area of the catalyst, while an elevated amplitude lead to more exothermic heat release and stronger aging over the complete catalyst, as visualized via conversion maps. A theoretical calculation of thermal loads by Arrhenius equation supports the results and indicates the direction of supplementary experimental approaches.
PubDate: 2023-07-20
DOI: 10.1007/s41104-023-00132-0
-
- Computer aided derivation of vehicle modules and functions from use cases
in order to create user orientated vehicle interior concepts-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Trends such as autonomous driving, non-driving related activities and digitalisation are contributing to a revolution in vehicle concept design. An aspect of this is the consideration of future use cases in shaping vehicle architectures. Future user scenarios can help identify relevant use cases, from which the user needs and system requirements can be derived. The derived requirements need to be matched to vehicle functions and architectural modules that can fulfil them. However, the optimal combination of functions and modules can be difficult to identify due to the numerous possibilities. The aim of this paper is to apply a matrix-based methodology that enables the systematic matching of requirements to vehicle functions and/or modules, as well as the identification of an ideal module/function combination for all the considered requirements. An example is presented that considers a requirement specification that has been derived from predetermined user needs. The requirements are matched to suitable functions/modules and the best possible combinations are determined using the proposed matrix-based methodology. Two optimal combinations are selected, one for a vehicle in the entry level segment and the other for a premium vehicle. The results indicate it is possible to determine an optimal combination for both vehicle segments considered, as well as the substantial influence the rating parameters have on the end result. Lastly, it is shown how the results can be applied by concept designers in order to draft tailored, user-orientated interior concepts.
PubDate: 2023-07-18
DOI: 10.1007/s41104-023-00134-y
-
- Accuracy requirements for the road friction coefficient estimation of a
friction-adaptive automatic emergency steer assist (ESA)-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract The number of traffic accidents resulting in personal injury and property damage is increasingly being reduced by effective advanced driver assistance systems (ADAS). Nevertheless, many traffic accidents still cannot be prevented today because they are due to wet, snow- and ice-covered roads. For this reason, the Institute of Automotive Engineering (IAE) of the Technical University of Braunschweig is investigating the road friction coefficient sensitivity and adaptation of advanced driver assistance systems (ADAS) currently in series production from 2018 to 2021 as part of the ‘Road Condition Cloud’ research project funded by the German Research Foundation (DFG) to increase driving safety, particularly on wet, snow- and ice-covered roads. In this article, the road friction coefficient sensitivity and adaptation of an automatic emergency steer assist is simulatively investigated. This assist overrides the driver to automatically execute an evasive maneuver. The driving maneuver used is a standardized obstacle-avoidance maneuver that is simulatively repeated on a dry, wet, snow- and ice-covered road. The road friction coefficient sensitivity shows that this test is already failed on a wet road because the simulated vehicle does not pass the second lane without errors. Subsequently, a road friction coefficient adaptation of the emergency steer assist is investigated. This adaptation varies the maximum lateral acceleration of the evasive trajectory depending on an estimated value of the road friction coefficient in order not to exceed the maximum adhesion coefficient of the wheels during the evasive maneuver. Ideally, the estimated value matches the true road friction coefficient so that the second lane is passed without errors even on a wet, snow- and ice-covered road. In contrast, an existing difference determines whether the second lane is reached. Finally, the necessary accuracy requirements of the road friction coefficient estimation are determined in an novel estimation error diagram. A road friction coefficient adaptation increases the driving safety of driver advanced assistance systems (ADAS) that are in series production today and future highly automated driving functions (HAF) and is necessary for automated driving because the driver is not present as a fallback level. The described results were presented before in [1].
PubDate: 2023-05-12
DOI: 10.1007/s41104-023-00131-1
-
- “Evaluation of an electromagnetically actuated drum brake
concept”-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract In publications and conferences on the subject of wheel brakes, different concepts of electromechanically actuated wheel brakes can be found, as well as investigations into their suitability for the use in passenger cars. The vast majority of these brakes are disc or drum brakes, which are actuated by an electric motor. In the present publication, a brake concept is considered, that combines an electromagnetically actuated full-pad disc brake with a 10″ duo-duplex drum brake. The brake concept is researched in a project regarding brakes for autonomous shuttles and thus dimensioned using vehicle data of an example shuttle. The electromagnet was designed using finite element methods and the overall brake prototypically realized. The validation of the system design is carried out in component and system tests. The results show the suitability of the concept for the selected vehicle in terms of dynamics, installation space and energy requirements. However, there is a strong dependence of the braking torque output on the frictional sliding speed. Using hypothesis-based testing, electromagnetic effects like eddy currents are ruled out as a possible cause and the friction coefficient within the full-pad disc brake is identified as the main cause for the loss in torque. Consequently, the associated development conflict is identified and lies in the double function of the flux-carrying material in the electromagnet, which also acts as a friction partner for the braking disc.
PubDate: 2023-04-26
DOI: 10.1007/s41104-023-00130-2
-
- Production cost modeling for permanent magnet synchronous machines for
electric vehicles-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract A cost model for the estimation of production costs of permanent magnet synchronous machines (PMSM) is presented, which allows to alter design choices such as wire technology, winding layout, cooling system, materials and more. With the goal to make results reproducible by others, the methods are explained in detail and used data and assumptions are given. The developed model helps to understand the interaction between the design of PMSM, manufacturing methods and the resulting costs. With it, different PMSM technologies and materials can be evaluated regarding its influence on the production costs, which is a perquisite to find the best compromise between performance and costs. Production volume is shown to be the most decisive factor for the resulting production costs. Between minimum and maximum assumed volumes, an average cost per unit reduction of 67% could be observed. Furthermore, the results imply that the winding production is responsible for the greatest part of the overall costs, followed by the rotor assembly (including rare earth magnets). When using the model to compare different wire types, it can be stated that up to a production volume of roughly 150,000 units/year, hairpin wires are more expensive to produce. Above this volume, hairpin windings will get cheaper than round wire windings due to its higher grade of automation of the production process. Through the conducted investigations and the presented results, it is demonstrated that the cost model can serve to evaluate technologies with regards to costs in the early development stage. This way a more holistic assessment of technologies for PMSM is possible, helping to find the ideal compromises between costs and performance and to increase the attractiveness of sustainable mobility.
PubDate: 2023-04-18
DOI: 10.1007/s41104-023-00128-w
-
- Experimental investigation of thermal swing piston insulation at single
cylinder gasoline engine-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract The reduction of carbon dioxide emissions and the corresponding increase in gasoline engine efficiency are crucial in engine development. Wall heat losses are a major cause of efficiency loss, accounting for 15–30% of the total fuel energy. One promising solution is the use of "thermal swing" coatings at the combustion chamber walls because of offering the possibility that the surface wall temperature following the working gas temperature, whereby the wall heat transfer can be reduced at any time during the engine cycle. This type of coating material is characterized by low thermal conductivity and, at the same time, low heat capacity. Based on the idea of the “thermal swing” coatings, yttria stabilized zirconia (YSZ) was selected as the coating material for the piston surface and its efficiency potential was experimentally investigated on a single-cylinder gasoline engine. The use of highly dynamic temperature probes in the piston allowed precise analysis of cycle-based temperature fluctuations, especially on the piston surface. The transmission of the piston temperatures was cable-based and accomplished through the use of a lever system in the engine. The measurement results confirmed the minimal impact on the efficiency that was determined in preliminary simulations. However, the effect of the coating could be established through the measurements.
PubDate: 2023-03-30
DOI: 10.1007/s41104-023-00129-9
-
- Experimental investigation of swirl motion of in-cylinder flow in CI
engine under firing condition due to preinjection using PIV and POD
techniques-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract The swirling motion of the intake air creates a flow field within the engine’s cylinder, which enhances the mixing of air and fuel, as well as combustion and emissions. Moreover, swirl formations in the cylinder and their subsequent breakdown into turbulence kinetic energy reflect the importance of in-cylinder flow structures. This study combined the PIV technique with the POD method to investigate the velocity fields in a single-cylinder diesel engine. The experiments were conducted at various pressure conditions and different engine rpm. Based on the obtained results, the average flow velocities from expansion to exhaust strokes were reduced in comparison with intake strokes. In all engine pressure and speed conditions, compression and exhaust strokes showed a significant change in flow patterns with changes in pressure and speed. At various crank angles, the POD modes demonstrated flow properties of the swirling motion, along with a dissimilarity feature and evolution of the in-cylinder flow.
PubDate: 2023-02-16
DOI: 10.1007/s41104-023-00126-y
-
- Psychoacoustic characteristics of different brake creep groan classes and
their subjective noise annoyance in vehicle and half-axle tests-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Brake creep groan is a severely annoying noise and vibration phenomenon. Especially on the Asian market, customer feedback about creep groan is common, indicating creep groan’s impact towards the quality impression of a car. Hence, treatment of these stick–slip-related creep groan phenomena is necessary. As numerous design conflicts exist for brake and axle, a complete mitigation of the phenomenon is often not possible. A reduction of creep groan’s annoyance by changing the noise’s level and characteristics is therefore typically aspired. One approach towards this goal could include the usage of psychoacoustics: This work deals with psychoacoustic characteristics of different creep groan classes. Low-frequency groan, high-frequency groan, and transition groan classes are compared regarding loudness, sharpness, roughness, fluctuation strength, and tonality. Standard statistic methods as well as machine learning approaches are applied on signals from vehicle tests and half-axle tests. Test results depict the different characteristics of each creep groan class. By mapping the results to the subjective rating of trained test drivers, the annoyance of different classes is compared. Low-frequency groan, dominated by longitudinal axle vibrations, is found to be least annoying. This low annoyance is best depicted by the psychoacoustic parameters loudness and roughness. Presented results allow an optimization of brake system design to reduce creep groan’s annoyance, leading to higher customer satisfaction and a more goal-oriented treatment of this NVH problem.
PubDate: 2023-02-14
DOI: 10.1007/s41104-023-00127-x
-
- HSS-measurements, high-speed sensitivity measurements, HSS-measurements: a
test procedure of tire cornering stiffness measurements at high speeds-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract A new tire measurement procedure needs to be developed due to the optimization of the predictable recommendation of tire validity with regard to high-speed sensitivity (HSS). The high-speed sensitivity of tires describes the robustness, stability and controllability of a vehicle against disturbances at high speeds up to 200 kph. The high-speed sensitivity can be roughly estimated using the tire cornering stiffness. The definition of a new tire test procedure for cornering stiffness measurements at 200 kph aims to map a realistic driver profile [driver profile: average driving behavior of car drivers (no trained drivers).] and driving behavior as well as handling characteristics including a real test track without violating the tire validity limits (temperature, friction, etc.). Attention has to be paid to the short duration of the test procedure. A new tire test procedure is introduced which was developed for cornering stiffness measurements at high speeds up to 200 kph to better predict the high-speed behavior of tires on the test bench (here: external drum test bench).
PubDate: 2023-01-28
DOI: 10.1007/s41104-022-00125-5
-
- Development of a Motion Control for a highly dynamic, self-propelled
driving simulator-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract The new concept of the self-propelled driving simulator comprises a hexapod, a yaw joint and a wheel-based motion platform with four individually steerable wheels. This concept provides a theoretically unlimited motion range, which especially enables highly dynamic drive maneuvers. To ensure an omnidirectional motion, the motion platform has to accelerate instantly in any direction. This requirement leads to the main challenges in the control system of the simulator: taking into account the nonlinear and transient tire characteristics and generating the target accelerations as expected by the driver. According to these requirements, the Motion Control is only for controlling the horizontal dynamics of the motion platform. The Motion Control presented in this paper includes various model definitions, especially regarding the essential tire characteristics considered within an extended HSRI (Highway Safety Research Institute) tire model. The Motion Control as Two-Degrees-of-Freedom control contains a Feedforward for generating target body forces, a Control Allocation for an optimal force distribution to the wheels, a Single Wheel Control as a specific control of the tire forces, and a Compensation Control on acceleration level. Investigation of this control by simulation, using a simplified reference model, already revealed a high controller performance regarding accuracy and quality. The optimal force distribution leads to an equal adhesion utilization and the Compensation Control compensates the remaining Single Wheel Control deviations. Difficulties only occur for the steering angle in the case of low velocity up to a standstill. Due to the exact input–output linearization, the Single Wheel Control leads to a singularity and instability. Therefore, the steering angle requires exceptional control in this case.
PubDate: 2023-01-18
DOI: 10.1007/s41104-022-00124-6
-
- Concept evaluation of a P2 MHEV SUV: application for possible EU7
boundaries-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract In this work, the experimental results that appeared in the recent published article “Current experimental developments in 48 V-based CI-driven SUVs in response to expected future EU7 legislation” are used to create a proper system simulation model with the simulation platform AVL CRUISE \(^\text {TM}\) M. This simulation model is then used to perform a system validation in order to evaluate the configuration with a straight-four compression ignition (CI) engine and the selected exhaust aftertreatment system (EAS). The mild hybrid electric vehicle (MHEV) has an 48 V P2 architecture and an 8-gear dual-clutch transmission (DCT) as a powertrain configuration. In addition to evaluating the 48 V potential, the simulation is performed with a conventional 12 V configuration, but also including an electrically heated catalyst (EHC). As boundary conditions for the simulation, we use the different engine operating mode (EOM) calibrations from the test bed to trigger the dedicated operation modes of the internal combustion engine (ICE). For the exhaust aftertreatment system (EAS), an optimization loop is performed to obtain a layout which will be near a serial production. This includes optimizing the heat losses and reducing the thermal mass of the canning. Beside the plant models, a hybrid control unit (HCU) is used, which includes an exhaust aftertreatment system coordinator (EASC). With these functionalities, the EOMs, electrically heated catalyst (EHC), electric machine (EM) and dosing control unit (DCU) are optimized to obtain the lowest possible nitrogen oxides (NOx) with an carbon dioxide (CO \(_{2}\) ) reduction potential. The targets for the emission limits are defined on the basis of the available information from the Consortium for ultra-Low Vehicle Emissions (CLOVE) and International Council on Clean Transportation (ICCT) proposals.
PubDate: 2023-01-02
DOI: 10.1007/s41104-022-00123-7
-
- Numerical modeling of diesel and polyoxymethylene dimethyl ether spray in
a high pressure chamber using the fischer primary breakup model-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract In the strive for the climate-neutral and ultra-low emission vehicle powertrains of the future, synthetic fuels produced from renewable sources will play a major role. Polyoxymethylene dimethyl ethers (POMDME or “OME”) produced from renewable hydrogen are a very promising candidate for zero-impact emissions in future CI engines. To optimize the utilisation of these fuels in terms of efficiency, performance and emissions, it is not only necessary to adapt the combustion parameters, but especially to optimize the injection and mixture formation process. In the present work, the spray break-up behavior and mixture formation of OME fuel is investigated numerically in 3D CFD and validated against experimental data from optical measurements in a high pressure/high temperature chamber using Schlieren and Mie scattering. For comparison, the same operating points using conventional diesel fuel were measured in the optical chamber, and the CFD modeling was optimized based on these data. To model the spray-breakup phenomena reliably, the primary break-up model according to Fischer is used, taking into account the nozzle internal flow in a detailed calculation of the disperse droplet phase. As OME has not yet been investigated very intensively with respect to its chemico-physical properties, chemical analyses of the substance properties were carried out to capture the most important parameters correctly in the simulation. With this approach, the results of the optical spray measurement could be reproduced well by the numerical model for the cases studied here, laying the basis for further numerical studies of OME sprays, including real engine operation.
PubDate: 2022-10-29
DOI: 10.1007/s41104-022-00120-w
-
- Performance of pure OME and various HVO–OME fuel blends as alternative
fuels for a diesel engine-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Since the potential for reducing CO2 emissions from fossil fuels is limited, suitable CO2-neutral fuels are required for applications which cannot reasonably be electrified, and therefore still rely on internal combustion engines in the future. Potential fuel candidates for CI engines are either paraffinic diesel fuels or new fuels like POMDME (polyoxymethylene dimethyl ether, short “OME”). Besides, also blends of these two types of fuels might be of interest. While many studies have been conducted on OME blends with fossil diesel fuel, the research on HVO–OME blends has been less extensive to date. In the current work, pure OME and HVO–OME blends are investigated in a single-cylinder research engine. The test results of the various fuel blend formulations are compared and evaluated, particularly with regard to soot-NOx trade-off behavior. The primary objective of the study is to examine whether the major potential of blending these two fuels is already largely exploited at low OME content, or if significant additional emission reduction potential can still be found with higher content blends, but still without the need to switch to pure OME operation. Furthermore, the fuel blend which is best suited for the realization of an ultra-low emission concept under the current technical conditions should be identified. In addition, three different injector designs were tested for operation on pure OME3-5, differing both in hydraulic flow and in the number of injection holes as well as their layout. The optimum configuration is evaluated with regard to emissions, normalized heat release and indicated efficiency.
PubDate: 2022-10-20
DOI: 10.1007/s41104-022-00122-8
-
- Passengers comfort during automated motorway lane changes: a subject study
on different lane change trajectories at the Stuttgart driving simulator-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract This article presents the setup and results of a recent subject study at the full-scale moving Stuttgart driving simulator. The study focusses on the passenger’s comfort during automated lane changes in a high-speed two-lane motorway scenario. The scenario contains different symmetric and asymmetric lane change trajectories, bends and road surface qualities. Each asymmetric trajectory is divided into two parts with different characteristics. The subjects input their subjective impression of comfort directly after each lane change on a tablet computer. The phase in which the vehicle leaves its previous lane and the phase in which the vehicle arrives at its target lane are rated individually. This enables a detailed effect analysis for the two characteristic parts of asymmetric lane change trajectory shapes. The evaluation method is able to determine subjective differences even at small objective changes. Result analysis verifies correlations between objective criteria describing the trajectory characteristics and the subjective comfort ratings. In addition, a curvature caused bias on the subjective ratings in bends is determined. The results motivate the curvature-dependent use of asymmetric lane change trajectories to improve comfort without reducing longitudinal velocity or increase lane change duration and thus maintaining traffic efficiency in terms of required traffic interspaces to cut in. The study data is further used for the development of a passengers’ comfort metric for automated driving functions.
PubDate: 2022-09-05
DOI: 10.1007/s41104-022-00118-4
-
- Combined experimental and simulative approach for friction loss
optimization of DLC coated piston rings-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract Piston rings cause significant friction losses within internal combustion engines. Especially the first compression ring, which is pressed onto the liner by high cylinder pressure, contributes significantly to the total friction loss of the piston assembly. The tribological behavior of the oil scraper ring is mainly related to the pretensioning force and can lead to high losses even at low and idle speed. Due to this, there is always a markable risk of wear for the contact surfaces of the piston rings and the cylinder. “Diamond-like carbon” coatings on the surface of the piston rings can prevent wear and are able to reduce friction in the ring-liner-contact. The purpose of this work was to investigate the tribological benefit of this coating-system on the compression and oil scraper ring. Experimental studies were carried out on a fired single-cylinder engine using the Indicated Instantaneous Mean Effective Pressure-method (IIMEP) for the crank angle-resolved detection of the piston assembly’s friction force. To be able to determine the component-related fractions of the friction loss and to quantify the hydrodynamic and asperity related parts locally and time dependent, an EHD/MBS model of the engine was created in AVL EXCITE and a simulative investigation was performed. This simulation was validated by the experimental work and provided detailed information about the individual contact conditions and gap height of each tribological contact of the piston group. The combined approach of measurement and simulation enabled the prediction of tribological aspects and performance in parameter studies on a virtual engine test bed.
PubDate: 2022-07-20
DOI: 10.1007/s41104-022-00115-7
-
- Comparison of the emission potential of renewable fuels in mono- and
bi-fuel systems from the point of view of a car fleet in an incoming
circular economy-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
Abstract: Abstract The aim of the study is to investigate the most effective approach to reduce the emissions of a SI-engine while using a limited amount of renewable fuel. In this study, the renewable fuels ethanol, methanol, 2-ethoxy-2-methylpropane (ETBE), acetone, and dimethylformamide (DMF) were investigated with various fixed admixture rates and with a fully variable on-board fuel mixture (Smart-Fuel concept). One result of the study is that for a Smart-Fuel concept using methanol a reduction in CO2 emissions of approx. 12.5% and a reduction in particulate emissions of approx. 60% can be achieved, when considering an entire car fleet. In terms of engine efficiency, as well as particulate emissions, the pure substances, except DMF, achieved significant improvements compared to standard gasoline. Compared with the pure substances, the Smart-Fuel concept achieved lower advantages; however, it used significantly less scarcely available renewable fuel in the process. Based on the limited availability of renewable fuels within the first stages of a circular economy, the Smart-Fuel concept proves to be a very efficient transition technology to achieve the CO2 reduction targets. The Smart-Fuel concept only uses renewable fuel when it is worthwhile in terms of efficiency or emissions. Predefined fuel blends in a mono-fuel concept offer much less reduction potential in terms of emissions than the Smart-Fuel concept. However, with respect to particulate raw emissions, especially for moderate mixing rates significantly increased particle emissions are sometimes observed, despite the overall very good performance of the pure substances.
PubDate: 2022-06-14
DOI: 10.1007/s41104-022-00110-y
-
