Self Inflation Research Paper

Design of Self Inflation Tires

Mani .S

Student, Department of Mechanical Engineering, Knowledge Institute of Technology, Salem, India [e-mail] I. Abstract Properly inflated tires are required for good performance of the vehicle. Self inflation is a growing field in military vehicles, but it is not popular among the commercial vehicles. In this paper I have designed my self inflation system for the commercial vehicle tires. The inflation system is very compact such that it could be fitted with the wheel itself. The system consists of an air compressor, air tank, pressure sensor and electronic indicators. The pressure sensor constantly checks for the pressure drop in the tire and maintains the required pressure. The

Due to the increase in the rolling resistance, more energy is required to drive the vehicle. This obviously increases fuel consumption of the vehicle. Thus the contact patch of the vehicle is more essential factor in deciding the fuel consumption of the vehicle based on the tire pressure.

VII. Older self inflation system Some of the self inflation systems are available for military vehicles and hummer. They follow the CTIS (Central Tire Inflation System) and AIRGO systems (1). Though these systems efficiently manage the inflation of tires, they are very costly and require more maintenance since the wear of the mechanical parts is more. In the recent year some companies have come up with the inflation systems of the scooters and two wheelers but not affordable by all due to its high cost.

VIII. Working of self-inflation system the compressor and the air tank are fixed with the tire rim itself. A pressure sensor constantly monitors the pressure drop in the tires. So whenever there is a pressure drop in the tire the pressure sensor inflated the tires and brings it to the required

Let the correct pressure of the car tire be 28 psi

The normal force acting on the vehicle at a flat surface = 1000*9.8 = 9800N

• 28 psi = 28/14.7 bar = 1.9047 bar

• 1.9047 bar = 1.9047*105 pa

• Contact patch = weight of the vehicle / tire pressure = 9800 / 1.9047*105 = 0.05145 m2

• Rolling friction = Crr * Nf = 0.015 * 9800 = 147.0 N

This 147.0 N is the actual Rolling resistance of the vehicle

Now if the pressure in the tire drops below 28 psi, the contact patch increases and the calculations are as follows

• 27.5 psi = 27.5/14.7 bar = 1.8707 bar

• 1.8707 bar = 1.8707*105 pa

• Contact patch = weight of the vehicle / tire pressure = 9800 / 1.8707*105 = 0.05238 m2

• If the normal force acting is 9800 N for 0.05144 m2 then the normal force acting for 0.05238 m2 will be

Nf = (9800 * 0.05238) / 0.05144 = 9977.1 N

• Rolling friction = Crr * Nf = 0.015 *