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Plug-in hybrid electric vehicles (PHEVs) with post-transmission parallel configuration attracted considerable attention due to their capacity to operate in either electric vehicle (EV) mode or hybrid electric vehicle (HEV) mode. Meanwhile, the added flexibility and multiple operation modes add additional challenges to vehicle control with acceptable drivability, particularly during the mode transition from the EV and HEV, since proper control is needed for the internal combustion engine (ICE), motor and coupling device to achieve smooth and fast transition, under various vehicle operation constraints such as mode-transition duration, vehicle acceleration fluctuation and friction loss of the dry clutch. In addition, the engagement of dry clutch features torque discontinuity due to slip-stick phenomenon and the dynamic behavior of the ICE further increases the nonlinearity of the powertrain system.

The domains of powertrain and brake systems are continuously merging due to the integration of electric drives and their ability to generate high acceleration and recuperative torque. However, high recuperative torque might lead to a locking motor and consequently cause a stability issue in electric and hybrid vehicles. This paper focuses on the special case of recuperation by coasting; i.e., the torque request is set after releasing the accelerator pedal. In this case the mechanical brake is not used. For off-highway vehicles this new feature in the inverter will suppress the slipping and locking up of the tires, without the need of additional external sensors. Slipping of the tires, e.g. when the tires lose grip, can occur due to excessive torque from the motor. In this case the motor torque exceeds the minimum feasible deceleration torque, given by road friction.

This paper presents an approach to numerically simulate greenhouse windnoise. The term “greenhouse windnoise” here describes the sound transferred to the interior through the glass panels of a series vehicle. Different panels, e.g. the windshield or sideglass, are contributing to the overall noise level. Attached parts as mirrors or wipers are affecting the flow around the vehicle and thus the pressure fluctuations which are acting as loads onto the panels. Especially the wiper influence and the effect of different wiper positions onto the windshield contribution is examined and set in context with the overall noise levels and other contributors. In addition, the effect of different flow yaw angles on the windnoise level in general and the wiper contributions in particular are demonstrated. As computational aeroacoustics requires accurate, highly resolved simulation of transient and compressible flow, a Lattice-Boltzmann approach is used.

Intake and exhaust system development is an important step in automotive design. The intake system must allow sufficient air to flow into the engine, and the exhaust system must allow exhaust gases to depart at the rear of the vehicle, without excessive pressure loss. These systems must also attenuate the acoustic pressure pulsations generated by the engine, such that the noise emitted from the intake and exhaust orifices is constrained within reasonable limits, and exhibits a sound quality in keeping with the brand and vehicle image. Pressure loss and orifice noise tend to be in conflict, so an appropriate trade-off must be sought. Simulation of both parameters allows intake and exhaust systems to be designed effectively, quickly, cheaply and promptly. Linear simulation approaches have been widely used for intake and exhaust acoustic prediction for many decades.

This paper presents new technique to estimate the projected operational forces, which is the operational forces with respect to the evaluation location, at the connections of the separated passive substructures with reciprocity. Since the transfer path analysis (TPA) is conducted with respect to the evaluation location, the forces for the substructures are, therefore, also required only to estimate the projected operational forces. In order to estimate the forces, the projected inertance matrix, which is the projection of the inertance matrix onto the subspace with respect to the evaluation location, is estimated without measuring it directly. The acceleration responses at the connections of the passive substructure are measured by the excitation at the evaluation location with the reciprocity. The technique decomposes the acceleration responses into the output and input element vectors on the subspace. With those vectors, the projected inertance matrix is constructed.

The optimal styling of the exterior surface of a vehicle and its suspension system have a direct impact on interior wind noise. Both are determined in early project phases when no hardware prototype is available. Turbulent flows produce both external pressure fluctuations at the vehicle shell, known as hydrodynamic excitation, and sound waves, known as acoustic excitation. Hydrodynamic and acoustic sound sources are evaluated separately and relative to each other in the frequency domain in order to perform evaluations of different body shapes. The technical aim of the presented work is to investigate how acoustic quantities measured at the outside of a vehicle can be used to assess the influence of styling modifications to interior sound pressure level. The methodology is required to be capable of being integrated into the serial development process and therefore be quickly applicable.

Transfer path analysis is a powerful tool to support the vehicle NVH development. On the one hand it is a fast method to gain an overview of the complex interplay in the vehicle noise generation process. On the other hand it can be used to identify critical noise paths and vehicle components responsible for specific noise phenomena. FEV has developed several tools, which are adapted to the considered noise phenomena: Powertrain induced interior noise and vibration is analyzed by VINS (Vehicle Interior Noise Simulation), which allows the deduction of improvement measures fast enough for application in the accelerated vehicle development process. Further on vehicle/powertrain combinations not realized in hardware can be evaluated by virtual installation of the powertrain in the vehicle, which is especially interesting in the context of engine downsizing from four to three or six to four cylinders.

The ELVA project (Advanced Electric Vehicle Architectures) was co-funded under the European Commission's 7th Framework Programme and had the goal of developing vehicle architectures specifically designed for electric powered vehicles. The consortium was formed by the Institute for Automotive Engineering (ika) of RWTH Aachen University (coordinator), Applus+ IDIADA, Volkswagen, Renault, Centro Richerche Fiat (CRF), Continental and the Swedish Vehicle and Traffic Safety Centre (SAFER).

Three wheeler taxis, commonly known as auto rickshaw are a popular means of transport in developing countries. However, low efficiencies and poor maintenance are common (especially in India). This results in high fossil fuel consumption, and very high urban air pollution due to these vehicles. Electrification of auto-rickshaw, therefore, is a potential solution to reduce dependence on fossil fuels, and reduce environmental pollution. However, this conversion is not straightforward. In this work, we investigate some of the challenges of converting an existing combustion engine powered auto-rickshaw to an electric auto rickshaw (electric vehicle (EV)). The cost of conversion to EV and sufficient charge storage capacity for driving range are important factors in the viability of such a conversion. The solution developed here is a design for low total ownership cost for short-range transport.

In the engine development process, the ability to judge NVH comfort as early as possible is a great benefit. The prediction of engine noise on the basis of a prototype engine without the need to install it in a real car significantly speeds up the development process and leads to a cost reduction, as prototype modifications can be evaluated faster. Meaningful predictions of the perceived NVH comfort cannot be achieved just by comparing order levels, but require listening to an auralization of the engine noise at the driver's position. With the methods of Transfer Path Analysis and Synthesis (TPA/TPS) a prototype engine can be virtually installed in a car using test-bench data. The interior noise can be estimated by combining source signals containing near-field airborne noise radiation and mount forces with transfer functions describing the transmission to the target position in the cabin.

The Aviation industry has come a long way since the invention of the aero-plane by the Wright Brothers. The shape and face of the industry has changed drastically since the time of its inception. With this paper, we intend to give a new perspective to the aviation industry. We try to do so by studying the aerodynamics of birds of prey, one of the most aerodynamically efficient examples created by nature. In this paper, we are publishing the results and inferences of Computational Fluid Dynamics (CFD) analysis on the 3D CAD model of a bird. The birds shortlisted for this exercise were the Red Tailed Hawk, the Peregrine Falcon and the Golden Eagle. The reason for this selection was their remarkable cruising speeds that reiterate the fact that they are natural examples of very high aerodynamic efficiency. Due to its larger size and availability of a clearer body size, shape and geometry, the Golden eagle was chosen as the final bird for analysis.

Since the last decade, the automotive industry has expressed the need to better understand how the different trim parts interact together in a complete car up to 400 Hz for structureborne excitations. Classical FE methods in which the acoustic trim is represented as non-structural masses (NSM) and high damping or surface absorbers on the acoustic cavity can only be used at lower frequencies and do not provide insights into the interactions of the acoustic trims with the structure and the acoustic volume. It was demonstrated in several papers that modelling the acoustic components using the poroelastic finite element method (PEM) can yield accurate vibro-acoustic response such as transmission loss of a car component [1,2,3]. The increase of performance of today's computers and the further optimization of commercial simulation codes allow computations on full vehicle level [4,5,6] with adequate accuracy and computation times, which is essential for a car OEM.

Dash panel is the most important path of structure-borne and air-borne interior noise for engine-driven vehicles. Reinforcements, which are added to dash panel, are mainly designed in order to suppress the structure-borne noise contribution from the dash panel. However, the effects of dash reinforcements do not seem clear in the viewpoint of air-borne noise. In this paper, the insulation performance of a dash structure with spot-welded reinforcements is studied through several STL (Sound Transmission Loss) tests and STL simulations. The results of this study could be utilized for increasing the sound insulation performance of vehicle body structure.

The driving comfort influences the customer purchase decision; hence it is an important aspect for the vehicle development. To better quantify the comfort level and reduce the experiment costs in the development process, the subjective comfort assessment by test drivers is nowadays more and more replaced by the objective comfort evaluation. Hereby the vibration comfort is described by scalar objective characteristic parameters that correlate with the subjective assessments. The correlation analysis requires the assessments and measurements at different vehicle vibration. To determine the objective parameters regarding the powertrain excitations, most experiments in the previous studies were carried out in several test vehicles with different powertrain units.

The advantages of hydraulic mounts over conventional elastomeric mounts for NVH refinement are well known, particularly in the area of engine and suspension mounts. Recently, hydraulic mounts have been successfully employed as body mounts between the frame and cab, principally to control freeway hop in pickup trucks. Due to their ability to provide increased damping at small displacements, hydraulic body mounts also have good potential to reduce smooth road shake. This paper documents the reduction in smooth road shake performance of a full size pickup truck. Hydraulic body mounts tuned to the frequency of the smooth road shake sensitivity area were added to the rearmost cab mount location. Both tire-wheel balance and uniformity were set to the highest production level specification allowed and the effect of hydraulic cab mount was measured experimentally during smooth road driving at medium to high speeds.

Strategies for weight reduction have driven the noise treatment advanced developments with a great success considering the already mastered weight decreases observed in the last years in the automotive industry. This is typically the case for all soft trims parts. In the early 2010's a typical european B-segment car soft trims weights indeed 30 to 40% less than in the early 2000's years. The main driver behind such a gap has been to combine insulation and absorption properties on a single part while increasing the number of layers. This product-process evolution was conducted using a significant improvement in the simulation capacities. In that sense, several studies presenting very good correlation results between Transmission Loss measurements and finite elements simulations on dashboard or floor insulators were presented. One may consider that those kinds of parts have already achieved a considerable improvement in performance.

The paper analyzes the characteristics of driveline torsional vibration of a RWD vehicle and provides the control methods of transmission rattle noise caused by the system torsional resonances. A driveline dynamic model of the RWD vehicle is established by multi-body dynamic method. The natural frequencies and modal shapes are calculated for each gear position and torsional vibration responses are predicted by forced vibration analysis. The system sensitivity and DOE are analyzed based on the parameterized stiffness, inertia and damping. The 2nd and 3rd order modal results show that the transmission shaft possesses the maximum amplitudes and its corresponding modal frequencies vary with different gear position. The sensitivity analysis results show that the system torsional vibration is significantly reduced by reducing clutch stiffness, increasing propeller shaft stiffness, raising half shaft stiffness, increasing the input shaft inertia and increasing the clutch damping.

An important part of future air vehicle design will be the development of a transient integrated aircraft system model. DC electric power system modeling poses particular challenges because they are highly dynamic and employ short time constant line replaceable units [1, 2, 3]. This paper describes an approach to modeling an aircraft's electric power system that uses simplified non-physics based models of the line replaceable units that are part of future 270VDC aircraft power systems. The model is an alternative to physics based models and is particularly useful for the initial phases of aircraft development before hardware development has occurred. A 270VDC aircraft power system model is constructed as an example using the unit models. Selected results will be presented.

Airship designers research application versions of systems with several ballonets for adjustment of airship roll and/or pitch as a whole. This requires effective automatic status management of each separate ballonet. But multi-ballonet system control issue encounters the absence of industrially measurable variables of each separate ballonet status. Thus status control issue of the system becomes uncertain. The fact requires the issue studying and shaping new scientific and technical solutions. This publication represents research results implying that fairly simple implementation and effective result can be achieved by application of fuzzy control concept. Its application is built on generating the representative quantity of fuzzy production rules. They are based on present set evaluation of known parameters and measured variables. This results in fuzzy but meaningful image of ballonet system status and airship as a whole. Thus achieving fairly good control over multi-ballonet system.

This article presents a structural analysis of the Unmanned Aerial System UAS-S4 ETHECATL. Mass, center of gravity position and mass moment of inertia are numerically determined and experimentally attested using the pendulum method. To determine the mass moment of inertia, a bifilar torsion-type pendulum is used for the Z-axis and a simple pendulum for the X and Y axes [14]. A nonlinear dynamic model is developed for the rotational motion about the center of gravity (Gs) of the tested system, including the effects of large-angle oscillations, aerodynamic drag, viscous damping and additional mass effects. MATLAB genetic algorithms are then used to obtain the values of mass moment of inertia that would validate the experimental data with the numerical results. The experiment used data gathered by three sensors: an accelerometer, a gyroscope and a magnetometer. Therefore, a method is used to calibrate these three sensors.