Search Results

Emissions and fuel consumption reduction for the year 2020 have led to the development of new powertrain solutions. The development of new electric concepts presents vehicle integration challenges, involving among others, NVH. Energy flow is controlled by inverters that transform the energy from DC to AC by working at frequencies of the order of kilohertz with a control strategy that can abruptly switch, and motors introduce high orders and electro-magnetic forces due to their topology, inducing phenomena that are not present in internal- combustion engine vehicles. In Particular, a common characteristic of permanent magnet motors is cogging torque, which is due to the attraction of the rotor poles and stator slots that induces a torque ripple causing comfort challenges at low speed and low torque conditions.

Vehicle simulation models are essential throughout the development process in the automotive industry. The benefit starts when benchmarking, continues when target setting and component selection and permits model-based development of controllers and strategies to ease the calibration of the vehicle. This paper studies the suitability of different vehicle performance and consumption simulation methodologies based on longitudinal dynamics for the variety of applications on vehicle development. These methodologies can be applied to architectures ranging from quadricycles to trucks and from combustion to hybrid. The main difference between methodologies is the solver, which influences the results and the area of application. The two main trends, namely forward and backward simulation, have features that make them not suitable for all the applications.

The running costs of heavy-duty trucks are strongly influenced by fuel consumption. Even a small improvement in fuel economy has a big effect on fleet cost savings and pollutant contamination. From the different possible sub-systems to be improved, reducing the rolling resistance of the tires is a cost-effective option due to its relatively high influence on the fuel consumption without negatively affecting the overall performance. Nevertheless, the other causes of resistance forces, such as mechanical friction and aerodynamics must be optimized as well. The focus of the work is to propose an accurate methodology specifically for heavy trucks for the proper evaluation of resistance forces to allow accurate fuel consumption simulation. For this purpose, the results obtained in proving ground were post-processed by applying different resistance forces characterization methodologies and the results were analyzed theoretically and numerically.

Over recent years IDIADA has developed several prototype electric vehicles as well as testing a number of electric powertrain configurations. Generally the electric motor output shaft delivers the torque to the transmission under a considerable level of high-frequency load variation and with noticeable torque irregularities that must be smoothed out in order to fulfill general NVH targets. This paper deals with the development phase of a prototype vehicle in which a specific testing activity was carried out to improve the overall NVH behavior of the powertrain. For this purpose, the mechanism of energy transference from the current to the motor and from the motor to the downstream driveline components was deeply characterized. The activity was aimed at smoothing the abrupt change in torque delivery and limiting the transfer of torque irregularities from the motor to the transmission.

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).

Reduction of CO2 emission is a mandatory objective for every actor in the field of automotive transport, and electric vehicles (EV's) are increasingly becoming an effective option for both OEMs and customers. However, components development and vehicle integration for EV's present new challenges that must be faced and new issues which need to be solved. In particular electric motor control systems are developed to achieve the same comfort conditions as in conventional vehicles. IDIADA developed a prototype electric commercial vehicle in which both the motor and driveline were integrated. The electric motor output shaft delivers the torque to the transmission under a certain level of load variation and with torque irregularities that must be smoothed out in the transmission components. This paper studies the results of the testing of the prototype vehicle carried out to improve the overall NVH behavior of the powertrain.

The focus of the work is to carry out a study of the relative impact of the rolling resistance measurements on CO₂ emission and fuel consumption reduction for heavy-duty vehicles. For the purpose of the study, friction coefficients of the tires from tire test machine according to UN/ECE Regulation No 117 test procedure have been used. The rolling resistance coefficient has also been obtained from SAE J1263 and SAE J2263 procedure for coast-down determination on proving ground. The fuel consumption has been simulated and tested on the proving ground by following FIGE standard cycle and stabilized speed conditions. A simulation tool has been developed and validated by testing different rolling resistance coefficient tires, analyzing their effect on the fuel consumption. The analysis of the contribution of the tires to fuel consumption achieved on the test track has been correlated with the experimental results and those obtained from the simulation tool.

The main advantages of electric LDT's, (Light-duty Trucks), namely: lower running and maintenance costs, zero-emissions and eco-friendly image heavily outweigh their disadvantages, specifically their higher charging time compared to ICE (internal combustion engine) vehicle refuelling and their shorter range. These advantages make electric LDTs viable because they are compatible with the driving cycles of fleet customers. Noise generated by electric LDTs is expected to be low compared to ICEs; however, the interior and exterior noise has high-frequency noise components that are usually subjectively perceived as unpleasant or annoying. The tonal components present in electric vehicles are judged as unpleasant by the vehicle's occupants, and other noise components that are usually masked by the ICE are clearly perceived, as the overall noise is lower.