An Experimental Approach to Understand Various Factors Influencing Low-Temperature Gear Shifting Performance

<div class="section abstract"><div class="htmlview paragraph">Gear shifting performance in vehicles is critical for smooth operation, especially under cold environment conditions or sub-zero conditions. In this comprehensive study, we delve into the multifaceted aspects that influence gear shifting behaviour during cold conditions especially after overnight vehicle soaking at low temperature below -8°C to simulate real world scenarios. Notably, our efforts on these bench trials focuses on isolating the synchronization load from the maximum block release force, a phenomenon arising from the interaction between synchronizer rings and gear cones in case of high drag of input and counter shafts. Our experimental trials involved multiple bench level testing for lower gear shifting case especially 2<sup>nd</sup> to 1<sup>st</sup> gear and 1<sup>st</sup> to 2<sup>nd</sup> gear shifting. Factors under study are focusing on changing the Oil (viscosity and quantity), different combination of synchronizer ring material, change of inertia etc.</div><div class="htmlview paragraph">Shifting load in cold condition mainly includes two loads, firstly synchronization load which can be checked with matching target RPM value of Input shaft and second load is block release of Synchronizer ring. This phenomenon of block release is very important in case of high drags of rotating components which is generally occurs during cold environment when transmission oil viscosity increases significantly. Stability of transmission oil viscosity to wide temperature range, especially in cold condition plays important role here to reduce block release load and same is also investigated here. These experimental findings provide valuable insights for optimizing gear shifting performance in cold environments. By understanding these factors, manufacturers and engineers can enhance vehicle drivability and reliability, ensuring seamless gear change even in challenging conditions.</div></div>