Design Methodology of Passenger Car Automatic Transmissions

Introduction

Automatic transmissions (ATs) are a type of transmission that allows the driver to select a gear without having to manually shift gears. ATs are typically more convenient and easier to operate than manual transmissions, which require the driver to shift gears manually.

ATs are used in a variety of passenger cars, from small sedans to large SUVs. They are also used in some commercial vehicles, such as buses and trucks.

Types of ATs

There are two main types of ATs: planetary gearsets and continuously variable transmissions (CVTs).

• Planetary gearsets are the most common type of AT. They use a set of planetary gears to change gears. Planetary gearsets are relatively simple and efficient, but they can only provide a limited number of gears.
• CVTs are a newer type of AT that use a belt or chain to change gears. CVTs can provide an infinite number of gears, which gives them a smoother ride than planetary gearsets. However, CVTs are also more complex and expensive than planetary gearsets.

Design Methodology

The design of an AT involves a number of factors, including:

• The type of vehicle. The type of vehicle will determine the size and power requirements of the AT.
• The desired performance. The desired performance will determine the number of gears and the gear ratios of the AT.
• The cost. The cost of the AT will be a major factor in its design.

The design process typically begins with a conceptual design. The conceptual design will define the overall layout of the AT and the type of gears that will be used. Once the conceptual design is complete, the detailed design can begin.

The detailed design will involve the design of the individual components of the AT, such as the gears, shafts, and bearings. The detailed design will also include the design of the control system for the AT.

The final step in the design process is testing. The AT will be tested to ensure that it meets the desired performance requirements. The AT will also be tested for durability and reliability.

Conclusion

The design of an AT is a complex and challenging process. However, by following a systematic design methodology, it is possible to design an AT that meets the desired performance requirements, cost, and durability.