Showing posts from February, 2011


FOUR STROKE INTERNAL COMBUSTION ENGINE This is an animated computer drawing of one cylinder of the Wright brothers' 1903 aircraft engine. This engine powered the first, heavier than air, self-propelled, manoeuvrable, piloted aircraft; the Wright 1903 Flyer. The engine consisted of four cylinders like the one shown above, with each piston connected to a common crankshaft . The crankshaft was connected to two counter-rotating propellers which produced the thrust necessary to overcome the drag of the aircraft. The brothers' design is very simple by today's standards, so it is a good engine for students to study to learn the fundamentals of engine operation. This type of internal combustion engine is called a four-stroke engine because there are four movements, or strokes , of the piston before the entire engine firing sequence is repeated. The four strokes are described below with some still figures. In the animation and in all the figures, we have colored the fuel/air i

Vehicle Steady State Directional Stability

Vehicle Steady State Directional Stability 27.5.1. Cornering Properties to Tyres Cornering Force and Slip Angle When the wheels are in motion tyres are subjected to vertical as well as side (lateral) forces due to road camber, side winds, weight transfer and centrifugal force caused while negotiating a curved paths and steering the vehicle on turns. When a lateral force acts on a road wheel and tyre, a reaction that is a resisting force acts, between the tyres tread contact patch and road surface and opposes any sideway motion. This opposing resisting force is known as the cornering force (Fig. 27.33), whose magnitude is equal to that of lateral force. The increase in this cornering force is roughly proportion to the increase in lateral force until the tyre looses grip with the ground. Fig. 27.33. Tyre trade contact patch distortion when subjected to side force. Beyond this point the proportionality does not hold good with further increase in lateral force so that tyre breakaway is lik

Steering Systems

Steering Systems 27.6.1. Function and Linkage of a Steering System The function of a steering system is to convert the rotary movement of the steering wheel in driver's hand into the angular turn of the front wheels on road. Additionally, the steering system should provide mechanical advantage over front wheel steering knuckles, offering driver an easy turning of front wheels with minimum effort in any desired direction. The main causes of stiff steering include (i) insufficient lubrication of the king-pins or steering linkage, (it) tyre pressure too low, (Hi) wheels out of track, i.e. toe-in not correct, and (iv) stiffness in the steering column itself, caused by lack of lubricant or over tightening. The steering system is designed to enable the driver to control and continuously adjust the steered path of the vehicle. Also it provides a positive response to whatever direction the driver may makes on the steering wheel. Fig.27.42. Relationship of steer angle speed and vehicle spee

Steering Components

Steering Components 27.7.1. Steering Column The steering column is primarily a supported shaft that connects the driver's steering wheel to the gear unit. The steering column in the modern automobile is a complex mechanism. It is designed to collapse in a collision to protect the driver. In some installations it may be tilted and telescoped to place it at a convenient angle for the driver. It also contains steering gear and transmission locks. A panic stop through braking slows the vehicle at the maximum deceleration rate of 6 m / s and the required time to stop the vehicle from 32 kmph is 1.5 seconds. This panic stop tends to lift the passengers and driver from their seats and carry them into front of the compartment, unless they are secured with seat and shoulder belts. In a head-on collision, two collisions actually occur. The first is the vehicle's collision with the object and the second is the occupants' collision with the instrument panel and windshield in the front