Project: Fluid Machinery
Design and analysis of a new hydraulic brake system in automobiles
1. Introduction
A fluid power system is designed to perform work. The work is accomplished by a pressurized fluid bearing directly on an operating fluid cylinder. A fluid cylinder produces a force resulting in linear motion.
The hydraulic brake system used in automobiles is a multi piston system (Figure 1). A multi-piston system allows applied forces to be transmitted to the pistons of the cylinders in a manner supports Pascal Law. The pressure set by the force applied on the brake pedal to the master cylinder (Figure 2) is transmitted undiminished to the wheel cylinders to apply force on the brake shoes.The brake pedal moves the piston of the master cylinder, forcing the brake fluid from the master cylinder through the tubing and hose to the wheel cylinders. The wheel cylinders contain two opposed pistons which are connected to the brake shoes at one end and other end of the shoes are pivoted. These brake shoes are fitted inside the brake drum. Each piston of wheel cylinder pushed the brake shoe against the wall of the brake drum, thus retarding the rotation of the wheel because of friction between the brake drum and brake shoe. When the applied pressure on the pedal releases, the springs on the brake shoes return the wheel cylinder pistons to the initial positions, thus forcing the brake fluid back to the master cylinder.
Figure 1: A hydraulic brake model of multi-piston system (Traman, 1990)
Figure 2: A detail hydraulic brake system used automobile (Traman, 1990)
2. Aims
The aim of this project is to exercise your theoretical knowledge of fluid power system and skills in practical applications in the area of automobile engineering.
3. Scopes
You are required to study, analyse and assess existing hydraulic brake system of onepassenger carconsidering information available in the web. Then design a new hydraulic brake system or modify the existing design that uses minimum human effort to brake pedal to get required braking action. This is a team submission and each team present their findings in week 6 workshop session.
Your submission should have the following items and headings:
(1) Introduction to fluid power system to automotive industries
(2) Literature review on hydraulic brake system on popular passenger cars: disk vs drum types
(3) Working principle of existing hydraulic brake system.
(4) Develop a case based on your research and develop a set of assumptions for your proposed design
(5) Design and analysis of a new brake system that uses minimum human efforts for braking action
(6) Safety check of pipes and pressure cylinders (thick-walled or thin walled analysis)
(7) Determine mechanical advantages (MA) and power required to have the braking action.
(8) Prepare an Excel calculation sheet to put input data, standard equations, creating plots to compare
(9) Compare MA and power of your new design to that of the standard design, taking data from the product design manual of car manufacturers.
(10) Health and safety practices required for maintaining the systems.
(11) Use proper drafting tools to show changes in your new design.
(12) Draw necessary fluid circuit diagrams
Your report must include executive summary, scopes and objectives, methodology, schematic diagrams where necessary, discussions and concluding remarks and Harvard referencing systems.
Reference
Fluid Power Training Manual (Traman), Naval Education and Training Command, Navedtra, 1990.