Development of Correlation Model for Manual Shift Transmission Efficiency Through Experimental Analysis

This work is an engineering effort to develop a correlation model of the transmission efficiency of a manual scooter type constant mesh transmission of two / three-wheeler application that can be used to predict, compare and validate the transmissions at the design phase. Initially the paper describes the transmission test rig developed for testing the transmissions. Two different transmissions are selected and their designs are studied for transmission parameters such as stiffness of transmission shafts and bearings, misalignment of shafts and bearings, lubrication specifications, gear tooth geometry and micro tooth geometry. The rig is used to map the transmission efficiency and different losses of each transmission over complete operating range of the engine torque and speed. A correlation model is developed relating the transmission efficiency to that of transmission parameters such as operating speed, torque, transmission ratio and tooth geometries. Finally the work presents methodologies to comparing transmissions, to predict transmission efficiency and to validate a transmission design without testing using this correlation model and this correlation model is validated.