Test Bench In Order Research Articles

Preliminary investigation of magneto-rheological fluid durability in continuous slippage clutch

Magneto-rheological (MR) devices, such as dampers, engine mounts and clutches, are now appearing in the ground vehicle industry. Although important work has been directed to assess the longevity of MR dampers, few studies have targeted the aspect of magnetorheological fluid (MRF) durability when used in continuous shear, such as in MR clutches. The objective of this research is to identify the degradation phenomena associated with MRF used in continuous shear and to understand the main causes and effects, in order to propose design improvements to enhance clutch durability. Experiments are conducted on two test benches in order to reproduce MRF aging in a controlled environment and to evaluate the proposed solutions. The effect of the operating conditions (shear rate, shear stress and temperature) on the long term degradation of the torque-current relationship is evaluated. Two degradation phenomena are identified: base oil expansion and particle oxidation. The dominant failure mode of the tested clutches is a MRF leakage resulting from the base oil expansion which occurs between 1.5 MJ/mL and 9 MJ/mL of dissipated energy depending of the operating conditions. Two solutions are proposed to extend clutch durability: 1- MRF circulation and 2-compliant elements.

Optimization of the inlet air line of an automotive turbocharger

This paper presents different aspects of air inlet behaviour near the inducer of a radial compressor and shows how the geometry can contribute to its stability and performance. Unfortunately, the space reserved for installation of an automotive turbocharger in a vehicle is constantly being reduced, so it is necessary to study the effects that elbows and abrupt changes in flow directions originate on the compressor performance. The work presented in this paper studies the effect that different 90° elbows have on the compressor with respect to its ideal, straight, no-elbow configuration, in order to obtain the best possible elbow configuration. The methodology followed has been to, initially, study different geometries in computational fluid dynamics code in order to obtain the best possible configuration. Then, several 90° elbows were constructed and characterized on a continuous flow test bench in order to validate the computational fluid dynamics results and to obtain optimum results. The elbows were then installed on a radial compressor and tested on a hot, continuous turbocharger test bench, where the compressor was characterized and maps were obtained with each different elbow. The results were compared with respect to the ideal, no-elbow configuration, which was taken as the base performance. After analysing the results obtained, it is possible to observe that in most of the cases, the elbows have a negative effect on the compression ratio, which tends to be reduced, especially at high rotor velocities and high air mass flow. On the other hand, the effect on the surge limit seems to be positive, as the surge line shifts to lower air mass flows, although the maximum mass flow allowed is reduced. It seems as if the compressor map shifts to the left with a reduction in compression ratio. From theoretical and experimental studies, it has been concluded that flow uniformity index and pressure loss are the most important factors affecting the performance of the compressor.

Methodology to design a vibration absorption footplate for motorcycle application: From phenomena investigation to prototype performance evaluation

The aim of this research is to reduce driver vibration exposure by acting on the modal response of key contact structures.The footplate is one of the components with which the driver comes into contact while riding. For this reason, footplate geometry and structural properties were investigated with a view to re-designing this component in order to reduce driver exposure.Due to the massive chassis area on which the footplate is constrained, vibrations induced by engine unbalances easily propagate in quasi-steady conditions on all surrounding components, inducing a width frequency band of load excitation. Even though the footplate geometry allows for fairly high natural frequencies, these could occur in the excitation range. Therefore, the first step of the methodology proposed entails the use of a numerical and experimental (modal analysis) procedure to identify the local vibration modes of the original components to detect if/when/how the resonances of the above mentioned components are excited.Due to an awareness of the weakness of the original solution, structural modifications, using numerical models, were studied. The footplate geometry was modified to minimize nodal displacement of the footrest beam binding. All structural modifications were designed, developed and installed on the vehicle.Finally, in order to predict modification efficiency, both the new footplate and the original one were experimentally compared. The comparison was made by means of modal investigations and by positioning the reference vehicle on a suitable roller test bench in order to simulate real working conditions.

The ATLAS tile calorimeter ROD injector and multiplexer board

The ATLAS Tile Calorimeter is a sampling detector composed by cells made of iron-scintillator tiles. The calorimeter cell signals are digitized in the front-end electronics and transmitted to the Read-Out Drivers (RODs) at the first level trigger rate. The ROD receives triggered data from up to 9856 channels and provides the energy, phase and quality factor of the signals to the second level trigger. The back-end electronics is divided into four partitions containing eight RODs each. Therefore, a total of 32 RODs are used to process and transmit the data of the TileCal detector. In order to emulate the detector signals in the production and commissioning of ROD modules a board called ROD Injector and Multiplexer Board (RIMBO) was designed. In this paper, the RIMBO main functional blocks, PCB design and the different operation modes are described. It is described the crucial role of the board within the TileCal ROD test-bench in order to emulate the front-end electronics during the validation of ROD boards as well as during the evaluation of the ROD signal reconstruction algorithms. Finally, qualification and performance results for the injection operation mode obtained during the Tile Calorimeter ROD production tests are presented.

Nonlinear Model Predictive Control of a Diesel Engine Airpath

In this paper we show the Nonlinear Model Predictive Control (NMPC) of an airpath of a diesel engine based on a Linear Parameter Varying (LPV) model. We used databased LPV modelling with real data from a dynamical engine test bench in order to obtain a nonlinear model of high quality. Because of the nonlinearity of the model the quadratic program (QP) of the NMPC needs to be set up afresh at each sampling instant, which is the main difference to standard linear MPC. For solving the QP efficiently, we employ the recently developed online active set as implemented in the software package qpOASES. We tested our controller in simulation on the LPV model identified on a mean value model and results show that the NMPC has a better tracking performance in terms of boost pressure and fresh air mass flow compared to the standard linear MPC approach also under the influence of a model plant mismatch.

Adaptive Control of Engine Torque with Input Delays

Control of the inner engine torque of a combustion engine is very crucial for the overall performance of a dynamical combustion engine test bench. The main problem thereby is the usually unknown system behavior of the combustion engine, the time delay of the accelerator actuator which is used to control the combustion engine. In general the combustion engine is mounted on a combustion engine test bench in order to adjust the parameters of the engine control unit (ECU). Hence the system behavior can change quite fast. In this paper we will present an adaptive approach to control the combustion engine torque. Measurements on a dynamical combustion engine test bench will verify the proposed approach.

Ab initio and dielectric studies of succinic acid and maleic acid in 1,4-dioxane

In a continuing effort to understand the hydrogen bond through the study of dielectric and computational conformal studies of dilute solutions, succinic acid and maleic acid are studied in solutions of 1,4-dioxane solvent. Dielectric studies give an account of the net dipole moment of the system under study, which is then compared with the values obtained from conformal analysis. The dielectric measurements were made at 303 K at a frequency of 9.83 GHz using a X-band microwave test bench in order to determine the relaxation times and the dipole moments. The static dielectric permittivity and the high frequency dielectric permittivity were measured using a LCR meter and an Abbe's refractometer, respectively. The results are inspected in comparison with the dipole moment results of ab initio calculations of some of the conformers in gas phase and in liquid phase. Gaussian-03 software package with 6–31G(d) basis set optimisation was used for this purpose. Onsager's reaction field model is used to study the solvation of the dicarboxylic acids in 1,4-dioxane. The results are interpreted in terms of the intermolecular and intramolecular hydrogen bond interactions in the dilute systems.

Calibration of flight model CCDs for CoRoT mission

CoRoT (Convection, Rotation and Transit) is a mission of high-accuracy photometry with two scientific programmes: asteroseismology and planet finding, using CCDs as detectors. Ten 2048×4096 CCDs manufactured by E2V (42-80) were calibrated on Meudon test bench in order to choose the best ones for flight. A very high instrument stability is needed. Taking into account the environmental perturbations (temperature, attitude control system jitter, radiations, etc.) we studied sensitivity of CCD gain and quantum efficiency to temperature and sensitivity of the output signal to bias voltages. Special attention was paid to pixel capacity and noise sources coming from dark current and pixel response non-uniformity. The calibration results together with the expected voltages and temperature fluctuations are compared with the specifications.

Micro-PHOENIX: Intense deuton beams production for SPIRAL II

The development of electron cyclotron resonance ion source (ECRIS) at LPSC Grenoble (previously ISN) covers a wide range of applications. Micro-PHOENIX is a compact source whose magnetic confinement is fully generated by permanent magnets. The extraction geometry has been specially designed to manage high currents with a double electrode extraction system to improve the beam characteristics at high voltage. The ECRIS can accept a microwave power frequency from 10 to 18 GHz. It has been installed as a universal injector on the new charge breeder test bench in order to perform the widest range of experiments including mono- or multicharged ion injections. To characterize the analyzed extracted beam, a new emittance meter based on electrostatic deflection plates has been set up and permits one to obtain online high resolution measurements. The first objective of the experiments was to fulfill the future SPIRAL II requirements. After a technical description of the Micro-PHOENIX ECRIS and its beam analysis system, the first experimental results obtained with a single puller electrode will be presented. Thus, a D+ intensity of 5 mA at 39 kV is easily delivered within a normalized rms emittance of 0.092 π mm mrad, which is well below the 0.2 π mm mrad limit assuring a 100% RFQ transport efficiency as computed for the LINAG project. A more extensive study of emittance versus plasma parameters is in progress.

14 GHz ECR operating and development at GSI

A 14 GHz Caprice ECR ion source is now in operation at the high charge state injector of the Unilac accelerator. Ions with charge to mass ratio ≥0.117 can be accelerated. Performance of the source with Uranium 28+ will be presented. A rebuilt ECR ion source similar to the Caprice operates at a test bench in order to investigate metal ion production and the afterglow operation mode.