# Tire

Topics: Pressure, Tire, Pascal Pages: 10 (2395 words) Published: September 30, 2012
[pic]

[pic]

ERODE - 638 052.

PERISTALTIC SELF-INFLATING TYRE SYSTEM

(A self inflating tyre system for automobiles using a peristaltic pump)

PRESENTED BY R.PRAVEEN KUMAR (26ME71) P.VIGNESH (26ME108) 3rd year mechanical 3rd year mechanical Paveen71989@yahoo.com vignesh3532@gmail.com phone no 9943920450 phone no 9894693532

Abstract:

Peristaltic Self-Inflating Tyre System (PSITS) is based on the peristaltic pump principle. This system is designed in order to constantly maintain the tyre pressure thereby improving safety of an automobile in times of emergency caused by perforation (by nails, screws, thorns, etc.,) or any other deformation. The PSITS uses a valve that pulls in air from the atmosphere. It then pumps the air into the under-inflated tyre using a peristaltic-pump action. The goal is to constantly maintain a specific pressure inside the tyre. The system consists of a thin tube that has a peristaltic part and a reservoir part, which has constant volume. The ratio of the total tube volume (peristaltic part volume + reservoir part volume) to the volume of the reservoir part defines the output pressure of the system.

Summarized, integrating a simple thin tubing into a tyre and mounting a simple valve on one end of the tubing will secure inflation of the tyre with small amounts of air at constant pressure at every revolution of the tyre using rollers (coupled with the rotating tyres) until the tyre pressure reaches the predefined critical pressure. Then the inflation stops.

Keywords:
Self-inflation, peristaltic pump, peristaltic part, reservoir part, Total tube volume, critical pressure, etc.,

INTRODUCTION:
The peristaltic self-inflating system is mainly concerned about eliminating the losses imparted to a vehicle by improper inflation. Before going into the working and the details of the design the knowledge of effects of improper inflation are to be known. Why is tyre inflation important?

Here are some important facts to note: • Tyre costs are a fleet's third largest expense, after fuel and labor. • In 2002, the U.S. commercial trucking industry spent an estimated \$4.4 billion for 19 million tyre units. (Modern Tire Dealer) • An American Trucking Association study found that over 90% of tyre damage is due to under inflation. • 10% under inflation shortens tread life by 6 – 9%. (TMC) • Under inflation in excess of 10% may result in blowouts, leading to increased liability issues, costly time delays and an increase in emergency road service calls at an average of \$500 - \$1,000 per call. (TMC) When tyres are under inflated, the tread wears more quickly. According to Goodyear, this equates to 15 percent fewer miles you can drive on them for every 20 percent that they're under inflated. Under inflated tyres also overheat more quickly than properly inflated tyres, which cause more tyre damage. The faded areas below indicate areas of excessive tread wear. Because tyres are flexible, they flatten at the bottom when they roll. This contact patch rebounds to its original shape once it is no longer in contact with the ground. This rebound creates a wave of motion along with some friction. When there is less air in the tyre that wave is larger and the friction created is greater and friction creates heat. If enough heat is generated, the rubber that holds the tyre's cords together begin to melt and the tyre fails. Because of the extra resistance an under inflated tyre has...