Temperature and torque variations analysis of the Continuously Variable Transmission System (CVT) of a vehicle Baja SAE
Bruno Cesar Tavares1; Murilo Patreze1; Arnaldo Medeiros1; Geice Paula Villibor1
1 universidade federal de viçosa
doi:10.20906/CPS/COB-2015-1070
Resumo
The continuously variable transmission system (CVT) brings some changes in relation to the stepped gear system that are used in traditional transmission systems, such as the better use of the torque range and engine power, and comfort based on the annulment the typical discontinuities common gearbox to change the relationship. However, there are some possible factors that can change the behavior of a CVT, not adapting more completely to its initial design. Some these possible elements, can emphasis the working temperature and the belt slip. Thus, the aim of the work was to verify the influence of CVT protection and tuning conditions in increasing the surrounding temperature and on the vehicle output torque. For this, the vehicle was coupled to a dynamometer for loading variation on the shaft and CVT was monitored at six points by means of thermocouples for checking the temperature variations. The tests were performed with CVT open and closed in six tuning conditions. The experiment was conducted in a factorial 6 x 2, with three replications, in completely randomized design. The data were submitted to analysis of variance using the F-test at 5% significance level. It was also carried out the test Tukey to verify difference between the averages. By means of variance analysis it was found that the protection increases the temperature and the interaction between the CVT protection condition and tuning influence the output torque. It is can be explained by the significant variation in the torque exerted by setting the preload springs, standing purely to temperature changes caused by the CVT configuration (open and closed). The average temperature in the CVT open and closed was 26.2 ° C and 55.9°C, respectively. The higher torque observed was 439.64 N m for the combination of spring pulley driven work with minimum preload and CVT closed. The reduction of the temperature can contribute to the maintenance of the life of system components, even higher torques were observed at higher temperatures. The information obtained
Palavras-chave: Baja SAE; CVT; Temperature; Power; Refrigeration