Transmission

Matching engine speed to road speed — manual to CVT. How vehicles change gear: manual gearboxes with synchronisers, torque-converter automatics with planetary gear sets, automated manuals, dual-clutch transmissions and continuously variable transmissions — their mechanics, calculations, pros and cons.

• Manual — Manual transmissions use a driver-operated clutch and gear lever. Learn the clutch, layshaft gearbox layout, constant-mesh gears and synchronisers, gear ratios and road speed per gear, shift quality, and final drive.
• Automatic — Conventional automatics use a torque converter and planetary gear sets shifted by clutches and brakes. Learn fluid coupling and torque multiplication, stall speed and K-factor, planetary gear ratios (Willis equation), clutch-to-clutch shifting, lock-up clutches and 8–10-speed designs.
• AMT — Automated manual transmissions add electro-hydraulic or electric actuators to a manual gearbox. Learn actuation of clutch and gear selection, shift sequence, torque interruption, shift time and its effect on acceleration, cost/efficiency benefits and applications in small cars and trucks.
• DCT — Dual-clutch transmissions use two clutches — one for odd and one for even gears — to pre-select the next gear and shift without torque interruption. Learn layout, clutch-to-clutch handover, wet vs dry clutches, launch thermal loads, shift times and control strategies.
• CVT — Continuously variable transmissions provide infinite ratios between limits. Learn push-belt/chain CVTs with variable pulleys, ratio spread, clamping force and slip, engine operating-line control, efficiency trade-offs, toroidal CVTs and hybrid e-CVTs.