| 1. |
- Anistratov, Pavel, et al.
(författare)
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Lane-deviation penalty formulation and analysis for autonomous vehicle avoidance maneuvers
- 2021
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Ingår i: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. - : SAGE Publications. - 0954-4070 .- 2041-2991. ; 235:12, s. 3036-3050
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Tidskriftsartikel (refereegranskat)abstract
- Autonomous vehicles hold promise for increased vehicle and traffic safety, and there are several developments in the field where one example is an avoidance maneuver. There it is dangerous for the vehicle to be in the opposing lane, but it is safe to drive in the original lane again after the obstacle. To capture this basic observation, a lane-deviation penalty (LDP) objective function is devised. Based on this objective function, a formulation is developed utilizing optimal all-wheel braking and steering at the limit of road–tire friction. This method is evaluated for a double lane-change scenario by computing the resulting behavior for several interesting cases, where parameters of the emergency situation such as the initial speed of the vehicle and the size and placement of the obstacle are varied, and it performs well. A comparison with maneuvers obtained by minimum-time and other lateral-penalty objective functions shows that the use of the considered penalty function decreases the time that the vehicle spends in the opposing lane.
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| 2. |
- Franzke, Randi, 1989, et al.
(författare)
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Experimental investigation of the air flow in a simplified underhood environment
- 2022
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Ingår i: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. - : SAGE Publications. - 2041-2991 .- 0954-4070. ; 236:10-11, s. 2272 -2282
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a simplified underhood environment is proposed to investigate the air flow distribution in a vehicle-like set-up and provide high quality measurement data that can be used for the validation of Computational Fluid Dynamic methods. The rig can be equipped with two types of front openings representative for electrified vehicles. Furthermore, it is possible to install differently shaped blockages downstream of the fan to imitate large underhood components. The distance between the blockages and the fan can be varied in longitudinal and lateral direction. The measurements are performed with Laser Doppler Anemometry at a fixed distance downstream of the fan. The results show that the lack of an upper grille opening in the configuration for a battery electric vehicle has a notable impact on the flow field in the reference case without any downstream blockage. However, the differences in the flow field between the two front designs become less when a downstream obstruction is present. The longitudinal and lateral position of the blockages have have a minor impact on the flow field compared to the shape of the obstacle itself.
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| 3. |
- Ghanaati, Ali, 1979, et al.
(författare)
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Design of a virtual test cell based on GMDH-type neural network for a heavy-duty diesel engine
- 2021
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Ingår i: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. - : SAGE Publications. - 2041-2991 .- 0954-4070. ; 235:2-3, s. 436-445
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Tidskriftsartikel (refereegranskat)abstract
- The engine development process faces big challenges from new strict emission regulations in addition to the need for fuel efficiency improvements. The Software-in-the-Loop (SiL) and Hardware-in-the-Loop (HiL) environments decreases the required time during engine development, calibration, verification, and validation of the product. An accurate and easy to build dyno-engine model with real-time operational ability is required for this purpose. Artificial Neural Networks (ANN) have shown ability to model dynamic and complex systems like internal combustion engines. In this paper, the Group Method of Data Handling (GMDH) algorithm was utilized to build an ANN model of a heavy-duty diesel engine. One objective is to reduce the amount of manual labor on the results during the ANN model development process. The GMDH algorithm is a self-organizing process that will find the system laws and optimize the model structure automatically in one iteration. The GMDH model results were compared with a model developed by Levenberg-Marquardt Backpropagation (LM-BP) algorithm. The ANN models used actuator signals from an Engine Management System (EMS) to simulate the engine operation parameters. As revealed by the simulation results, the ANN models successfully predicted engine torque, fuel flow, and NOx concentration. The GMDH model as a self-organized model reduced lead time, had slightly higher transient cycle accuracy, had fewer inconsistent predictions, and demonstrated better extrapolation capability. The prediction accuracy for transient operation was improved by shifting the predicted value by calculating time delay and a decrease of 76.66% for fuel flow and 66.51% for NOX concentration in model accuracy were achieved. The GMDH dyno-engine model can be effectively applied as a virtual test cell instrument for testing, calibration, and optimization purposes.
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| 4. |
- Hyttinen, Jukka, et al.
(författare)
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Constitutive rubber model suitable for rolling resistance simulations of truck tyres
- 2022
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Ingår i: Proceedings of the Institution of mechanical engineers. Part D, journal of automobile engineering. - : SAGE Publications. - 0954-4070 .- 2041-2991.
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Tidskriftsartikel (refereegranskat)abstract
- Tyres are a vital vehicle component forming an interface between a vehicle and the road, enabling the generation of braking, steering and traction forces. However, they also generate rolling resistance which researchers have tried to minimise through the years for environmental and economic reasons. Despite numerous attempts to model rolling resistance of tyres there still does not seem to exist a simple, flexible and accepted way of modelling rolling resistance in the time domain as well as parametrising models in an easy and accessible way. This study explores a simple and intuitive way of parametrising a hyperviscoplastic parallel rheological framework. In the experimental part of this study, rubber samples with various amounts of carbon black filler are extracted from a truck tyre section and tested using dynamic mechanical analysis. The test data was used to parametrise the material model. The model consists of Mooney-Rivlin hyperelasticity, 40 Prony elements and 8 perfectly plastic elements with Ogden hyperelasticity. The paper introduces a method to obtain a large number of parameters using only six tuneable parameters, which simplifies the tuning of the model drastically. The parametrised model is suitable for tyre rolling resistance simulations with frequency and strain amplitude dependency of the storage and loss modulus. A wide range of strain amplitudes and frequencies can be covered with the proposed method and it is possible to achieve a good fit for the storage and loss modulus values with the benefit of only a few tuneable parameters. Additional Prony or plastic networks do not increase the amount of tuneable parameters. Moreover, the method can be used to parametrise the material using manual iterations which is generally not possible for a parallel rheological framework with such a large amount of parameters.
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| 5. |
- Häggström, Daniel, et al.
(författare)
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Optimization of synchronizer cone angle with regard to manufacturing tolerances of cone roundness and cone angle
- 2020
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Ingår i: Proceedings of the Institution of mechanical engineers. Part D, journal of automobile engineering. - : SAGE PUBLICATIONS LTD. - 0954-4070 .- 2041-2991. ; 234:2-3, s. 681-688
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Tidskriftsartikel (refereegranskat)abstract
- The effects of manufacturing tolerances on the maximum focal temperature has been investigated by transient thermomechanical simulations. Both relative cone angle and cone out-of-roundness for molybdenum and carbon fibre reinforced polymer synchronizers were evaluated. It was shown that cone out-of-roundness significantly increases the focal contact temperature for that specific cone but has little impact on the opposing cone. Two populations of measured synchronizers were evaluated, and it was shown that the maximum focal surface temperature can be decreased in almost all tolerance cases by introducing a relative angle between the cones.
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| 6. |
- Irfan, Muhammad, 1986, et al.
(författare)
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Minimizing synchronization time of a gear shifting mechanism by optimizing its structural design parameters
- 2020
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Ingår i: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. - : SAGE Publications. - 2041-2991 .- 0954-4070. ; 234:2-3, s. 488-504
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Tidskriftsartikel (refereegranskat)abstract
- A gear shifting mechanism is modeled in GT-Suite software. The mechanism has three main bodies: sleeve, ring, and gear. Results obtained from the simulation show that GT-Suite model can predict gear shifting process. Synchronization processes for three conditions of nominal, road grade, and vibrational motion of the master are studied in six cases by considering the sleeve and the gear as a master alternatively. The optimization based on the GT-Suite model is performed for each case to find the minimum gear shifting time based on variations of 17 structural design parameters. Minimum synchronization time is found almost same in all cases. It is concluded from closeness of the optimization results that average of the parameter values can be considered as optimized values for all cases. At the end, robustness of the optimized structural design parameters are analyzed with respect to the road grade, amplitude, and frequency of oscillatory excitation of rotational motion of the master.
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| 7. |
- Li, Xiaojian, 1991, et al.
(författare)
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A new method for performance map prediction of automotive turbocharger compressors with both vaneless and vaned diffusers
- 2021
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Ingår i: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. - : SAGE Publications. - 2041-2991 .- 0954-4070. ; 235:6, s. 1734-1747
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Tidskriftsartikel (refereegranskat)abstract
- A new approach to predict the performance maps of automotive turbocharger compressors is presented. Firstly, a polynomial equation is applied to fit the experimental data of flow coefficient ratios for the centrifugal compressors with both vaneless and vaned diffusers. Based on this equation, the choke and surge flow coefficients under different machine Mach numbers can be quickly predicted. Secondly, a physically based piecewise elliptic equation is used to define compressors’ characteristic curves in terms of efficiency ratio. By introducing the flow coefficient ratio into the efficiency correlation, the empirical coefficients in the piecewise elliptic equation are uniquely calibrated by the experimental data, forming a unified algebraic equation to match the efficiency maps of the compressors with both vaneless and vaned diffusers. Then, a new universal equation, which connects the work coefficient, the impeller outlet flow coefficient and the non-dimensional equivalent impeller outlet width, is derived by using classical aerothermodynamic method. The off-design pressure ratio is predicted based on the equivalent impeller outlet width with less knowledge of the compressor geometry and no empirical coefficients. Finally, three state-of-the-art turbocharger compressors (one with vaneless diffuser, two with vaned diffusers) are chosen to validate the proposed method, and the results show a satisfactory accuracy for the performance map prediction. This method can be used for the preliminary design of turbocharger compressors with both vaneless and vaned diffusers, or to assess the design feasibility and challenges of the given design specifications.
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| 8. |
- Meng, Zhiwei, 1996, et al.
(författare)
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GIVA: Interaction-aware trajectory prediction based on GRU-Improved VGG-Attention Mechanism model for autonomous vehicles
- 2023
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Ingår i: Proceedings of the Institution of Mechanical Engineers. Part D, Transport engineering. - 2041-2991 .- 0954-4070. ; In Press
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Tidskriftsartikel (refereegranskat)abstract
- Predicting future trajectories is crucial for autonomous vehicles, as accurate predictions enhance safety and inform subsequent decision-making and planning modules. This is however a challenging task due to the complex interactions between surrounding vehicles. Existing methods struggled to extract deep representations and often overlook spatial dependence. To address this problem, this paper introduces GIVA, an interaction-aware trajectory prediction method based on the Gated Recurrent Unit (GRU)-Improved Visual Geometry Group (VGG)-Attention Mechanism model. GIVA first encodes the historical trajectories of the target vehicle and its surrounding vehicles using a GRU Encoder. Next, an Interaction Module, which combines the Improved VGG Pooling Module and the Attention Mechanism Pooling Module, effectively captures spatial interaction features between vehicles. The Improved VGG Pooling Module extracts more detailed and effective interaction information, while the Attention Mechanism Pooling Module emphasizes the importance of surrounding vehicles for the target vehicle’s future trajectory. Lastly, the dynamic encoding feature of the target vehicle and the fused interaction feature are concatenated and input into a GRU Decoder to generate the future trajectory. Experiments on the public Next Generation Simulation (NGSIM) dataset showcase the effectiveness of GIVA compared to existing prediction approaches, demonstrating its potential for improving autonomous vehicle performance.
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| 9. |
- Papaioannou, Georgios, et al.
(författare)
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Optimal design of passenger vehicle seats with the use of negative stiffness elements
- 2021
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Ingår i: Proceedings of the Institution of mechanical engineers. Part D, journal of automobile engineering. - : Sage Publications. - 0954-4070 .- 2041-2991. ; 234:2-3, s. 610-629
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Tidskriftsartikel (refereegranskat)abstract
- A seat that provides good vibration isolation is of prime importance for passenger's safety and health. The main conflict in seat suspensions implies that the increasing initial deformation of the system (increase in "static discomfort") leads to better isolation of accelerations (increase in "dynamic comfort"). Many researchers have focused on overcoming or at least suppressing this conflict between load support capacity and vibration isolation by modeling new suspension systems, such as the so-called negative suspension systems. However, apart from the modeling of new suspension systems, optimization is an important part in designing a seat and finding the best compromise between these two objectives. Thus, in this work, four types of seat suspension systems with embedded negative stiffness elements are implemented and optimized in order to be benchmarked. Three of them have already been tested either in passenger or in an off-road vehicle seat. All the vibration isolators are optimized with genetic algorithms in respect to static and dynamic factors of ride comfort by applying constraints oriented to the objectives and the design of the structure. The optimization is implemented for two excitations, which correspond to a vehicle driving over road profiles of Classes A and B, and the common solutions are outlined.
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| 10. |
- Papaioannou, Georgios, et al.
(författare)
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Skyhook control strategy for vehicle suspensions based on the distribution of the operational conditions
- 2021
-
Ingår i: Proceedings of the Institution of Mechanical Engineers, Part P. - : SAGE Publications. - 1754-3371 .- 0954-4070 .- 2041-2991.
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Tidskriftsartikel (refereegranskat)abstract
- In this work, a novel distribution-based control strategy of semi-active vehicle suspensions is tested under different conditions. The novelty lies in the use of an appropriate threshold in the operational condition of the control algorithm, with which the operational conditions severity is quantified and the state of the damper is controlled according to the magnitude of the operational conditions and not their sign. The value of the threshold depends on the vibrations induced to the sprung mass by the road profile. In order to be evaluated, the operational conditions of the algorithm are fitted to a t-student distribution. The cumulative distribution function of this distribution is used in order to decrease the fraction of the sample operating with the damper’s stiff state. The strategy is applied to traditional SH control algorithms and is tested using a quarter car model excited by different road excitations. A sensitivity analysis for various threshold values is performed, investigating the impact of adopting the cumulative distribution functioned (CDF) controller to various performance metrics. The results illustrate an increase of up to 13% in the ride comfort of the passengers and increase of 6% in the road holding of the vehicle. Both are achieved by minimizing the switches of the damping ratio up to 80%
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| 11. |
- Perricone, Guido, et al.
(författare)
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A proposed driving cycle for brake emissions investigation for test stand
- 2020
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Ingår i: Proceedings of the Institution of mechanical engineers. Part D, journal of automobile engineering. - : Sage Publications. - 0954-4070 .- 2041-2991. ; 234:1, s. 122-135
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Tidskriftsartikel (refereegranskat)abstract
- Particulate matter emission factors from vehicle brakes are difficult to assess directly from the field. Moreover, there is a lack of a standardized cycle and test stand for evaluating brake emissions. For these reasons, a test cycle was developed from real driving data collected from a car. This new test cycle was implemented on an inertia disc brake dynamometer appositely designed for brake particle emission studies. Results reveal that, for the brake system used as an example, the obtained emission factors for the urban driving conditions studied are comparable to EURO 6 regulations in terms of particle number and comparable to EURO 4 levels in terms of mass with brake emission factors equal to 4.37-6.46 x 10(11) particles/km and 44-48 mg/km, respectively.
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| 12. |
- Romano, Luigi, 1994, et al.
(författare)
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Synthesis and comparative analysis of three model-based observers for normal load and friction estimation in intelligent tyre concepts
- 2021
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Ingår i: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. - : SAGE Publications. - 2041-2991 .- 0954-4070. ; 235:6, s. 1629-1642
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Tidskriftsartikel (refereegranskat)abstract
- Recently, the growing trends towards autonomous driving and full automation of terrestrial vehicles have intensified the need for intelligent and interconnected systems to collect and communicate reliable data in real-time. Since the tyres represent the primary sensing system between the vehicle and the ground, it comes natural to designate them to acquire information about their interaction with the road. Intelligent or smart tyre technologies can, indeed, be used to estimate both vehicle’s performance and environmental conditions, leading to handling, NVH and comfort improvements. Inspired by some encouraging results found in previous works, in this investigation we present three model-based estimators to detect the forces acting in the contact patch for an intelligent tyre. The underlying mathematical foundation is the Flexible Ring Tyre Model (FRM), which is able to describe the in-plane dynamics of intelligent tyre systems. More specifically, it represents the tyre treadband by means of a flexible ring restrained at its mean radius by a viscoelastic foundation. Due to its relatively simplicity, the FRTM allows to obtain a closed-form solution for the treadband displacements, accelerations and circumferential strain, whilst being accurate enough to capture all the relevant phenomena concerning the tyre dynamics. The governing Partial Differential Equations (PDEs) of the system are reduced to a set of coupled Ordinary Differential Equations (ODEs) by performing the Fourier series expansion. An optimal observer is then designed based on the Unscented Kalman Filter to account for the nonlinearities which arise when the vertical load acting on the tyre and the friction coefficient are included in the augmented state space representation. The three different technologies considered in this study are: strain, displacement, and acceleration-based intelligent tyres. All of them are shown to be capable of estimating the quantities of interest – the actual state of the system, the normal force and the adhesion coefficient – with high accuracy in very short times. Furthermore, the robustness of the proposed approach is validated by considering a step variation in both the vertical load and the available friction. The performances of the observers are finally compared by using the RSS and MSE indices.
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| 13. |
- Sadeghi Kati, Maliheh, 1979, et al.
(författare)
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Gain-scheduled H Controller Synthesis for Actively-steered Longer and Heavier Commercial Vehicles
- 2020
-
Ingår i: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. - : SAGE Publications. - 2041-2991 .- 0954-4070. ; 234:7, s. 2045-2065
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Tidskriftsartikel (refereegranskat)abstract
- This paper proposes a gain-scheduled controller synthesis for improving the lateral performance and stability of articulated heavy vehicles by active steering of the selected towed vehicle units. The longitudinal velocity is on-line measurable, and it is thus treated as a scheduling parameter in the gain-scheduled controller synthesis. The lateral performance of four articulated heavy vehicles, including existing Nordic heavy vehicles and prospective longer articulated heavy vehicles, are investigated with and without active steering and compared with a commonly used conventional tractor–semitrailer. The control problem is formulated as an ℋ∞H∞ static output feedback, which uses only information from articulation angles between the steered vehicle unit and the vehicle unit in front of it. The solution of the problem is obtained within the linear matrix inequality framework, while guaranteeing ℋ∞H∞ performance objectives. Effectiveness of the designed controller is verified through numerical simulations performed on high-fidelity vehicle models. The results confirm a significant reduction in yaw rate rearward amplification, lateral acceleration rearward amplification, and high-speed transient off-tracking, thereby improving the lateral stability and performance of all studied heavy vehicles at high speeds.
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| 14. |
- Sharifzadeh, Seyed Mojtaba, 1988, et al.
(författare)
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An effective tyre to road friction estimation applied to heavy vehicles
- 2023
-
Ingår i: Proceedings of the Institution of mechanical engineers. Part D, journal of automobile engineering. - : Sage Publications. - 0954-4070 .- 2041-2991. ; 237:14, s. 3547-3558
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge about the tyre to road friction is central to many vehicle functions as well as the overall performance of the vehicle. In this paper, a new real-time algorithm is presented for estimating the coefficient of friction using available on-board sensor information. A computationally efficient algorithm is presented, that reduces resources usage compared to previously published approaches. Issues connected to heavy vehicles and friction estimation is addressed, such as wind up of hub assembly and vehicle speed sensing. The performance of the algorithm is illustrated on data sets acquired from the test track recordings in winter conditions.
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| 15. |
- Svahn, Mattias, et al.
(författare)
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Optimum dog-leg angle for mass and bearing force optimization of multistage gear reduction
- 2022
-
Ingår i: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. - : SAGE Publications. - 0954-4070 .- 2041-2991. ; 236:13, s. 2795-2805
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Forskningsöversikt (refereegranskat)abstract
- This paper describes a method to minimize bearing forces as well as bearing and housing mass for a multistage gear reduction. This is done by finding the optimum dog-leg angles for the stages while leaving other aspects of the design unaltered. The optimization is demonstrated first for spur gears, and then for helical gears typically used in electric vehicles. A numerical example shows how bearing forces and mass of bearings and housing are reduced considerably by choosing the optimum dog-leg angle.
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| 16. |
- Wachter, Erik, et al.
(författare)
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Path control in limit handling and drifting conditions using State Dependent Riccati Equation technique
- 2020
-
Ingår i: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. - : SAGE Publications. - 2041-2991 .- 0954-4070. ; 234:2-3, s. 783-791
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Tidskriftsartikel (refereegranskat)abstract
- Tyres operated at or close to their friction limits show a highly nonlinear motion to force response. This state is called limit handling. The objective of this research is to minimize lateral path tracking error while the tyres operate in limit handling. The State Dependent Riccati Equation technique is employed to develop a feedback-feedforward steering controller. It gives a systematic approach to take into account model nonlinearities such as combined slip tyre characteristics. Furthermore, the controller is implemented in a test vehicle and tested on a low friction skid pad. The controller shows robust path tracking performance even when the rear wheels are operated beyond their friction limits, and large body sideslip prevails.
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| 17. |
- Wramner, Lina, 1979
(författare)
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Analysis of power split vibration absorber performance in heavy-duty truck powertrains
- 2020
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Ingår i: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. - : SAGE Publications. - 2041-2991 .- 0954-4070. ; 234:10-11, s. 2509-2521
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Tidskriftsartikel (refereegranskat)abstract
- The current development of more efficient combustion engines leads to an increase in engine torsional vibrations; therefore, new technology is needed for reducing the vibrations transmitted from the engine to the driveline. In this article, the concept of power split vibration absorber is evaluated. A mathematical model of the power split vibration absorber is presented, and an analytical study shows how different design parameters affect the power split vibration absorber performance. Numerical simulations with models representing typical heavy-duty truck powertrains are used in the evaluations. It is concluded that for a low level of damping, the power split vibration absorber can provide significantly lower vibration amplitudes than a corresponding dual mass flywheel within a limited speed range. If the power split vibration absorber is optimised for the critical low engine speeds, an overall decrease in the level of vibration can be obtained, but a larger installation space than with a conventional dual mass flywheel would probably be required.
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| 18. |
- Wramner, Lina, 1979
(författare)
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Dual-mass flywheels with tuned vibration absorbers for application in heavy-duty truck powertrains
- 2020
-
Ingår i: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. - : SAGE Publications. - 2041-2991 .- 0954-4070. ; 234:10-11, s. 2500-2508
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Tidskriftsartikel (refereegranskat)abstract
- As the heavy-duty combustion engine development goes towards lower rotational speeds and higher cylinder pressures, the torsional vibrations increase. There is therefore a need to identify and study new types of vibration absorbers that can reduce the level of torsional vibrations transmitted from the engine to the gearbox. In this work, the concept of a dual-mass flywheel combined with a tuned vibration absorber is analysed. The tuned vibration absorber efficiently reduces the vibration amplitudes for engine load frequencies near the tuning frequency, but it also introduces an additional resonance into the system. By placing the tuned vibration absorber on an intermediate flange between the two dual-mass flywheels, the introduced resonance frequency will be lower than the tuning frequency and a resonance in operating engine speed range can be avoided. Numerical simulations are used to show how the torsional vibration amplitudes in a heavy-duty truck powertrain are affected by the tuned vibration absorber and how the different parameters of the tuned vibration absorber and the dual-mass flywheel affect the torsional vibrations and the resonance frequencies.
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| 19. |
- Xiao, Sen, et al.
(författare)
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Investigation of chest biomechanical response by variation of restraint loads in frontal impact
- 2020
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Ingår i: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. - : SAGE Publications. - 2041-2991 .- 0954-4070. ; 234:5, s. 1377-1388
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Tidskriftsartikel (refereegranskat)abstract
- The seatbelt restraint load is one of the primary sources of occupant chest injury. Thus, studying the different biomechanical responses of chest by varying the seatbelt loads will result in a significant improvement in seatbelt protection performance. Based on the high-biofidelity mechanical dummy model, a sled-dummy test was conducted to investigate the differences in chest injury outcomes caused by the variation of seatbelt load paths or load processes. The chest kinematics and kinetics are compared to determine the influence of load factors on these biomechanical outcomes. Results show that chest injury severity has a positive nonlinear correlation with impact speed. However, the injury risk is mainly determined by the seatbelt peak load in the chest deflection analysis. The results of this study can provide a reference to seatbelt safety design and optimization. The model and method can be used in other research works on the biomechanics of frontal impact.
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| 20. |
- Ydrefors, Lisa, et al.
(författare)
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Rolling resistance and its relation to operating conditions : A literature review
- 2021
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Ingår i: Proceedings of the Institution of mechanical engineers. Part D, journal of automobile engineering. - : SAGE Publications. - 0954-4070 .- 2041-2991. ; 235:12, s. 2931-2948
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Tidskriftsartikel (refereegranskat)abstract
- For at least 50 years, the interest in understanding and reducing the rolling resistance of pneumatic tyres has been growing. This interest is driven by the need to reduce vehicle fuel consumption and CO2-emissions, for environmental and economic reasons. The amount of rolling resistance generated depends on the vehicle type, tyre properties and operating conditions. The main objective of this literature review is to provide an overview of the most influential operating conditions with respect to rolling resistance, their effects and their connection to different measurement techniques. The examined operating conditions are the inflation pressure, the temperature, the curvature of the test surface, the load, road surface, speed, torque, slip angle and camber angle. In addition, the definition of rolling resistance is investigated, which shows lack of harmony in the literature. There are important areas where little research can be found and where further research would be valuable. Examples of such areas are effects of the torque, slip angle and camber angle on rolling resistance, thorough comparison between flat-surface and drum measurements, effects of temperature difference between laboratory measurements and actual driving on rolling resistance and evaluation of Unrau’s formula for temperature correction of rolling resistance measurements.
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