DEVELOPING SETS OF TIRES’ PRESSURES FOR BALANCING CARS WHILE SUDDENLY BRAKING

PRESENTED BY: AMMAR AL-HOGAIL

(427102215 )

Abstract

In the Kingdom of Saudi Arabia about 3,500 people die and 28,000 are injured in over 153,000 traffic accidents each year. Official sources attribute the causes of these crashes to aggressive driving, speeding, failure to obey traffic signals, poor car maintenance, including tires and brakes. None considered the influence of the effect of the tires’ pressure on balancing the car in a case of sudden emergency is showed up and required to stop the car

This project aims to develop some designed sets and criteria to clarify this point. In addition, the project helps in developing a mecha-electronics mechanism to equalize the tires’ pressures. This final step is beyond this project. Two experiments will be carried out to set up those measures. The first experiment consists of measuring a moved displacement and angle of rotation from the car’s normal path when the car stopped suddenly from moving at a constant speed of 80 km/hr. The independent variables are car type (i.e., 3 different cars) and tire pressures (i.e., 30, 25, 20, 15, 10, and 5 psi in all four tires). The second experiment will be carried out similar to the first one except that one tire out of the four tires in the car will be different in the value of its pressures. The other three tires will be kept at 25 psi. The changing tire pressure will be right front, left front, right rear, or left rear. Multi-regression analysis will be implemented to develop those sets of guidelines to protect the car from slipping.

Abstract

The monitoring of tire pressure is an important concern of the automobile industry and safety as well. More and more vehicle manufacturers had included the tire pressure real time monitoring system as one of the basic equipments. The US government has even passed the law. This explains the importance of tire pressure monitoring. The system that we designed aims at this matter. The 2000 TREAD Act which requires automakers to gradually provide tire pressure monitoring systems for vehicles sold in the US will correct this problem for new vehicles [2]. The TREAD Act will also reduce energy use because it demands that manufactures install a tire pressure monitoring system (TPMS) in the future automobiles

Introduction

Friction is the force resisting the relative motion of solid surfaces, fluid layers, and/or material elements sliding against each other. It may be thought of as the opposite of "slipperiness

Friction

Friction

• Ff  is the force exerted by friction (in the case of equality, the maximum possible magnitude of this force).

• U is the coefficient of friction, which is an empirical property of the contacting materials,

•   N is the normal force exerted between the surfaces.

   

Analysis of the problem   

1. When of the wheels explodes, the leash trembles because the pressure is gathered at the front wheels.

2. At the time of explosion, the car deviates away of the track because of the difference between pressures in wheels.

3. The car may overturn if the car mass was driven forward and the driver tried to turn it to right or left side.

How to overcome difference in wheels pressure   

 The solutions, from my point of view are: 1. Try to find a degree of balance between air pressures in the wheels at the time of explosion. 2. If wheels slide due to explosion, we have to try to increase the friction to avoid slide. 

How this work? 

   

The idea in brief is that at the time of explosion to one of the wheels, air pressure is decreased equally in the other wheels. We do this through a device connected to all wheels. This device works through sensor that feels the sudden change in air pressure and works on decreasing the pressure in other wheels. Such change in air pressure of car wheels helps in making a degree of balance and increase the degree of friction. This leads to little probability of sliding.

Problem Statement   

Traffic accidents are unjustifiable waste of money, property and life. Here are some statistics on traffic accidents in Riyadh :

Statistics of Riyadh City (1410-1419H)

Accidents Toll :

   

Injuries Toll:

Problem Statement

Death Toll:

   

Driving Licences:

Problem Statement

Problem Statement   

  Country Year Deaths per 10,000 vehiclesAlgeria 1996 24.4Oman 1996 16.4Saudi Arabia 1994 13.9South Korea 1996 10.6Vietnam 1996 10.6Turkey 1996 10.5Thailand 1996 9.5Malaysia 1996 8.5Libya 1996 8.3Iran 1995 5.9Hong Kong 1996 5.1Cyprus 1996 3.7Bahrain 1996 3.2Lebanon 1994 2.4Taiwan 1996 2.1

Methodology   

The relationship between air pressure and wheels friction on the road will be identified when pressing on brakes through a definite test. This test helps in providing a good understanding of the relationship between decrease and increase of air in the tires.

General description of the experiment:   

80 km / hour

General description of the experiment:   

Click on the brakes

General description of the experiment:   

Displacement

Experimental Variables:    

•  Dependents:1. Distance: The displacement that the car moved in a brake mood.

2. Angle of rotation: The angle that car is shifted from its path and rotated while stopping.

Experimental Variables:    

Independents:  Symmetrical: One-Way Analysis

Tire Pressure (all four tires)psi

Car Type 1 2 3

30252015

Factors affecting the braking distance:   

Vehicle road speed Pedal application force Ambient temperature Brake rotor temperatures Tire temperature Tire pressure. Road surface temperature

Factors affecting the braking distance:   

Vehicle road speed (60 h/km) Pedal application force (constant) Ambient temperature (At same time) Brake rotor temperatures (Wait between two experiments) Tire temperature (Wait between two experiments)Road surface temperature (Wait between two experiments) Tire pressure

Collected data of tire pressure.   

psi Car1

Stopping Distance(meter)

Car2

Stopping Distance(meter)

Car3

Stopping Distance(meter)

1 2 1 2 1 2

30 13.65 13.80 14.30 14.20 12.00 12.21

25 13 12.95 13.50 13.40 11.50 11.73

20 12.80 12.50 13.12 13.45 11.20 11.47

15 12.20 12 12.83 12.90 11.20 11.00

Results   

Results revealed the followings :1. There isn't clear difference between the successive pressures 30,

25, 20, and 15, whereas there is a clear difference between 30 and 15. In fact, this ensure that the less the pressure, the less the brakes distance (See Figure 11).

2. From the experiment, we can find equation suitable for the three cars according to the pressures from 30 to 15 as follows:

 Braking Distance (in m) from 60 km/h = 10.699 + (pressure *0.085)

The relationship between the brakes distance and tires pressure

   

14

19

24

29

34

11 11.5 12 12.5 13 13.5 14 14.5

bra

kes

dis

tan

ce (m

)

tires pressure (pis)

The relationship between the brakes distance and tires pressure

car1

car2

car3

Discussions   

The project’s results agreed with the results of published works that are available in the literature. Let’s see what are the differences and the agreement with other studies.

The NHTSA study:    

Surface 15 psi 20 psi 25 psi 30 psi 35 psi

Wet Concrete 148.8 147.5 145.9 144.3 146.5

Dry Concrete 142.0 143.0 140.5 140.4 139.8

Wet Asphalt 158.5 158.6 162.6 161.2 158.0

Dry Asphalt 144.0 143.9 146.5 148.2 144.0

The 1998 Pontiac Firefly Study:    

The 1998 Pontiac Firefly Study:    

Conclusion   

Based on the results of the project, drivers must check their car tires’ pressures to the manufacture recommendations. A positive relationship was revealed between tire pressures and braking moved distance expressed in a linear regression equation. Yes, it is very dangerous for blowing a tire among the other in the car that makes that car unbalance. Therefore, it is needed to have equipment that sucks air from the rest tires automatically. This project considers the environment and economics aspects for fewer tires destroyed and save human being lives.

References   

[1] Available 2 march 2011 at http://www.car-accidents.com/country-car-accidents/saudi-arabia-car-accidents-crash.html . [2] Marcus, B., Harald, S.＆ Thomas, W.2002.Model based fault detection of vehicle suspension and hydraulic brake system, Mechatrnics 12,pp.999-1010. [3] US106th Congress.2000.Transportation Recall Enhancement, Accountability andDocumentation（ TREAD） Act. Public Law 106-414, November 1, 2000. [4] Department of Transportation,2000. RIN 2127-A133 Federal Motor Vehicle Safety Standard: Tire Pressure Monitoring Systems, Controls and Designs. National Highway Traffic Safety Administration, 49 CFR Part 571, Docket No. NHTSA 2000-8572. [5] Friedrich, A.,2002. Fuel saving potential from low rolling-resistance tires.Presentation for the Umweltbundesamt at the September 2002,CEC Tires Workshop in Sacramento. [6] Keijiro, I., Inchiro, Y., 1996. A Study on the mechanism of tire/road noise, JSAEReview 17, pp.139-144.

References   

[7], Ferdinand P.; E. Russel Johnston, Jr. (1996). Vector Mechanics for Engineers (Sixth ed.). McGraw-Hill. p. 397. [8] Meriam, J. L.; L. G. Kraige (2002). Engineering Mechanics (fifth ed.). John Wiley & Sons. p. 328.  [9] Introduction to Tribology – Friction". Retrieved 2008-12-21 [10]  Engineers: Handbook Friction Coefficients [11] The Engineering Toolbox: Friction and Coefficients of Friction". Retrieved 2008-11-23. . [12] General department of traffic, Ministry of Interior, Statistic Report #1429. Available 2March 2011 at http://www.moi.gov.sa/wps/portal/Main/Statistics/1429. [13] Al-Ghamdi, A.S., 1999. Traffic Accidents in Saudi Arabia: Causes Consequences and Solutions. KACST, Riyadh.  

References   

[14] Traffic General Directorate, 2003. Annual Traffic Report. Ministry of the Interior, Riyadh. [15] Al-Saleh, M., 1990. Child injuries due to traffic accidents. In: Proceedings of the International Symposium on Traffic Accidents, Security Forces Hospital, Riyadh. [16] Ministry of Interior, 2001. Statistics on Traffic Accidents Resulting from Tire Failure. Public Security, The Special Forces for Road Security, Operation Administration, Studies Division, Kingdom of Saudi Arabia. [17] Vehicle road speed http://f1-dictionary.110mb.com/braking_tech.html [18] thermal expansion http://wapedia.mobi/en/Thermal_expansion_coefficient [19] Braking Distance (in feet) from NHTSA testingStopping Distance from 60 mph http://www.nhtsa.gov/cars/rules/rulings/tirepressure/LTPW3.html [20] Results, 20-60 psi: 1998 Pontiac Firefly http://www.metrompg.com/posts/tire-pressure-rolling-resistance.htm  

THANKS!