No abstract

The modern development process of winter tires not only requires intense subjective and objective evaluation of the tire properties on the vehicle, but also requires knowledge about the influence of relevant tire characteristics on vehicle driving behavior. It is important to understand the influences of ambient conditions, such as temperature, track surface (asphalt vs corundum) and tire inflation pressure on tire behavior. Tire characteristic results of a parametric study, using a fully climate-controlled interior drum test stand will be presented. The effect on tire characteristics and the resulting vehicle behavior will be discussed using vehicle dynamics simulation. Furthermore the consequences for an optimal design of modern high performance winter tires will be presented.

This paper summarizes results from a recent program of tire-vehicle system research, using simulation techniques to identify the influence of tire characteristics on the vehicle response functions of yaw rate and lateral acceleration. Tire characteristics such as cornering stiffness, cornering stiffness-wheel load dependency, self-aligning torque, and dynamic tire behavior were varied with respect to a control tire. Computer simulations of vehicles undergoing a steering wheel pulse input were carried out using ADAMS full vehicle models and the Magic Formula tire model. Frequency responses were obtained from these vehicle handling simulations. The Four Parameter Evaluation Method of Lateral Transient Response was used to judge the vehicle handling performance. The influences of tire characteristic properties on the vehicle lateral transient response are explained by this method.

The hermetically sealed, single-cylinder Stirling engine of beta-type of a new concept with pressurized crankcase and permanently lubricated bearings has been tested as a demonstrator unit with provisional electric generators and a natural gas burner with the purpose of evaluating the concept.Test results show better values than predicted due to lower friction losses in bearings and internal seals. Starting can be made at lower gas temperatures than other kinematic Stirling engines.The balancing of inertia forces has turned out to be up to expectation and the permanently lubricated bearings have performed well.Continued evaluation will be made in the application prototype, which has the desired outside shape.

The dynamic stability of heavy trucks, as spinout, jackknifing, and rollover, is highly dependent on vehicle configuration, driving maneuver, and the force and moment characteristics of tires. Increasing safety requirements on the handling performance of heavy trucks demand tools that allow a tire design engineer to predict tire influences on the tire/vehicle system dynamic behavior. The computer simulation of handling performance of vehicles offers possibilities of evaluating influences of tire design changes on handling properties in any developing stage of new tire lines. Thus, modern simulation techniques may contribute to the building and testing of tires in an early design stage. This paper presents results from a recent program of tire/vehicle system research, applying tire/vehicle testing and simulation techniques to a 40 ton truck-semitrailer combination. The goal of this work is to visualize the possibilities of state-of-the-art simulation technologies on the tire design process. Tire force and moment characteristics can be calculated from the tire layout by an advanced tire model. The tire model for this type of calculation is a multibody system. Calculated and measured dynamic tire characteristics are used for the full vehicle handling simulation in ADAMS. Extensive tire characteristic testing on the road and test stand was done to improve and validate the tire model. Vehicle handling tests as steady state circular and lateral transient response tests were done for the empty and laden vehicle with different tires to prove the vehicle model. With the use of the simulation of the tire and vehicle behavior, the tire design engineer will be able to judge tire characteristics of different variants in an early design stage. Vehicle dynamic simulation studies up to instability as spinout, jackknifing, and rollover can be performed using modern CAE methods without harming man and environment, but subjective and objective tire evaluation still remains necessary for approving and validating the predicted results.