TECHNICAL TERMS OF AUTOMOBILE ENGINEERING !!

1.)ACKERMAN PRINCIPLE – Steering geometry in which the outer ends of the steering arms are bend slightly inward so that when the vehicle is making a turn, inside wheel will turn more sharply than the outer wheel.This principle produces toe out on turns.

2.)AIR BLEEDER – A device used to remove air from a hydraulic system.Types include a needle valve, capillary tubing to the reservoir, and a bleed plug.

3.)ASPECT RATIO– The ratio of the width to the length. On tyres, it is the fully inflated height divided by the cross section.

4.)BODY ROLL – The vehicle body leaning sideways as the vehicle turns

5.)DAMPERS– are nothing but a piston in a cylinder filled with oil or gas.The damper restrains undesirable bounce of the sprung vehicle mass and restrains the wheel assembly from loosing ground contact by being excited at its natural frequency.

6.)DEAD AXLE – Axle that does not rotate or deliver power but merely forms a base upon which wheels may be mounted.

7.)FLOATING CALIPER DISC BRAKES – Disc brakes using a caliper mounted through rubber bushings which permit the caliper to float, or move, when the brakes are applied.

8.)MASTER CYLINDER– The liquid filled cylinder in the hydraulic braking system where hydraulic pressure is developed by depression of the brake pedal or movement of the brake lever.

9.)OVER STEER – The tendency of a vehicle to turn sharper than the turn selected by the driver.

10.)PROPELLER SHAFT – A shaft in the power train that extends from the transmission to the differential and transmits power from one to the other.

KNOW WHY CONSTRUCTION MACHINES ARE PAINTED YELLOW IN COLOUR !!

You might have noticed that most of the construction machines are yellow in colour. We will discuss the reason for this in this article.

Warning signs are frequently yellow, yellow/black striped, or red. And additional to that, yellow is quite a bright and noticeable colour that doesn't usually appear elsewhere in our modern world, so is immediately easily noticed. So, in short yellow is the colour that gets noticed by everyone easily.

On the construction site, man and machine are working side-by-side and close together. For this reason, every construction machine must be as salient and noticeable as possible in order to be visible and to avoid accidents.

Therefore, excavators, cranes, coaters and therelike are painted in the most conspicuous colors, such as yellow, red, orange or another warning color, so that they stand out from the dust, the ground and the other colors on a construction area or roadworks. After all, it would be fatal if a construction worker could not see a construction machine coming.

However, the exact color depends on several factors. First of all, the color of the construction machines often depends on the respective company or the manufacturer of the equipment. For example, some companies are painting their machines as a recognition symbol rather yellow, others red. Partially, however, the colors are also regulated by law.

KNOW WHY FIRING ORDER IS 1-4-3-2 , RATHER THAN 1-2-3-4 !!

Every engine cylinder must fire once in every cycle. This requires that for a four-stroke four cylinder engine the ignition system must fire for every 180 degrees of crank rotation. For a six cylinder engine the time available is only 120 degrees of crank rotation. The order in which various cylinders of a multi cylinder engine fire is called the firing order. The number of possibilities of firing order depends upon the number of cylinders and throws of the crankshaft.

Let us see firing order of various engine configurations:

For 4-Cylinder engines the possible firing orders are: 1-3-4-2 or 1-2-4-3

For 3 Cylinder engine 1-3-2

8 Cylinder in-line engine 1-6-2-5-8-3-7-4

For a 6-Cylinder engine firing orders can be: 1-5-3-6-2-4 or 1-5-4-6-2-3

You might be wondering why firing order is not in sequence.Why for a four stroke engine firing order is 1-3-4-2 rather than 1-2-3-4 ? We will discuss about factors on which firing order depends in this article.


Following factors must be considered before deciding the optimum firing order of an engine. These are:

(i) Engine vibrations

(ii) Engine cooling


Consider that the cylinder number 1 of the four-cylinder engine, is fired first. A pressure generated in the cylinder number 1 will give rise to a force on the bearings. If the next cylinder fired is cylinder number 2, this imbalance in load on the two bearings would further aggravate the problem of balancing of the crankshaft vibrations & would result in severe engine vibrations. If we fire cylinder number 3 after cylinder number 1, the load may be more or less evenly distributed as cylinder 3 is far from cylinder 1 so vibrations will be distributed evenly due to symmetry of engine.

Further, consider the effect of firing sequence on engine cooling. When the first cylinder is fired its temperature increases. If the next cylinder that fires is number 2, the portion of the engine between the cylinder number 1 and 2 gets overheated.This results in uneven heating as half engine is heated.If we fire cylinder 3 after cylinder 1 then this results in equal heating of the engine which reduces thermal stress and aids in efficient cooling.