Verification of the Shifting Mechanism of Clutchless Geared Smart Transmission Using the Compact Car Size Test Bench

The existing transmissions have limitations related to driving comfort, manufacturing price, or driveline efficiency. To satisfy the complex demands of users, the clutchless geared smart transmission (CGST) is proposed. The CGST has a distinctive structure combining the geared transmission and planetary gear system. Especially, its pseudo-clutch system including a planetary gear system and an electric motor acts as a clutch to change the gears smoothly. In this research, the shifting mechanism of the CGST was focused to verify their feasibility. To realize its sequential shifting steps including a speed control phase and a torque control phase of CGST operation, the compact car size test bench containing CGST as transmission was developed and tested. From the test, starting flywheel with 1st gear engaging by speed synchronization of carrier gear to output shaft was shown to be possible, and up shifting from 1st gear to 2nd gear was also performed with continuous power delivery to the flywheel. Based on the experimental result, the shifting mechanism was verified. In the future, we will quantify the shifting smoothness by using modified test bench.