Gear Timing Mechanism for Valvetrains

The objective of this thesis is to provide an overview of geared valvetrain. In introduction are described individual types of gears and their application in combustion engines. Then, the thesis is divided into three chapters. The first chapter provides a thorough analysis of geared valvetrain. Also, individual parts of valvetrain together with alternative methods of valve timing are briefly introduced. The chapter then follows to examine the working principle of gears, how forces and moments are transmitted, advantages of introducing helical gears instead of spur gears, different ways of gear manufacturing, gear material selection, heat treatment of gears and common gear failure mechanisms. The second chapter examines pros and cons of using geared valvetrains. The third chapter shows examples of how are geared valvetrains applied in tractors, trucks, ships, trains, cars and motorcycles. In the conclusion, the main advantages of using geared valvetrains are discussed and the whole thesis is summerized