ANTI LOCK BRAKING SYSTEM

Anti-lock-braking system
An anti-lock braking system, or ABS (from the German, Antiblockiersystem) is a safety system on motor vehicles which prevents the wheels from locking while braking.
A rotating road wheel allows the driver to maintain steering control under heavy braking, by preventing a locked wheel or skid, and allowing the wheel to continue to forward roll and create lateral control, as directed by driver steering inputs. Disadvantages of the system include increased braking distances under some limited circumstances (ice, snow, gravel, soft surfaces), and the creation of a "false sense of security" among drivers who do not understand the operation, and limitations of ABS.
History
Anti-lock braking systems were first developed for aircraft in 1929, by the French automobile and aircraft pioneer, Gabriel Voisin, as threshold braking an airplane is nearly impossible. An early system was Dunlop's Maxaret system, introduced in the 1950s and still in use on some aircraft models.
A fully mechanical system saw limited automobile use in the 1960s in the Ferguson P99 racing car, the Jensen FF and the experimental all wheel drive Ford Zodiac, but saw no further use; the system proved expensive and, in automobile use, somewhat unreliable. However, a limited form of anti-lock braking, utilizing a valve which could adjust front to rear brake force distribution when a wheel locked, was fitted to the 1964 Austin 1800.
How Antilock Brake Systems Work
ABS on your vehicle you should always refer to the specific service and repair manuals for your vehicle.
The ABS is a four-wheel system that prevents wheel lock-up by automatically modulating the brake pressure during an emergency stop. By preventing the wheels from locking, it enables the driver to maintain steering control and to stop in the shortest possible distance under most conditions.
During normal braking, the ABS and non-ABS brake pedal feel will be the same. During ABS operation, a pulsation can be felt in the brake pedal, accompanied by a fall and then rise in brake, pedal height and a clicking sound.
Vehicles with ABS are equipped with a pedal-actuated, dual-brake system.

The hydraulic system consists of the following:
· ABS hydraulic control valves and electronic control unit
· Power brake booster
· Brake master cylinder
· Necessary brake tubes and hoses

The anti-lock brake system consists of the following components:
· Hydraulic Control Unit (HCU).
· Anti-lock brake control module.
· Front anti-lock brake sensors / rear anti-lock brake sensors.
Anti-lock Brake System (ABS) operates as follows:
· When the brakes are applied, fluid is forced from the brake master cylinder outlet ports to the HCU inlet ports. This pressure is transmitted through four normally open solenoid valves contained inside the HCU, then through the outlet ports of the HCU to each wheel.
· The primary (rear) circuit of the brake master cylinder feeds the front brakes.
· The secondary (front) circuit of the brake master cylinder feeds the rear brakes.
· If the anti-lock brake control module senses a wheel is about to lock, based on anti-lock brake sensor data, it closes the normally open solenoid valve for that circuit. This prevents any more fluid from entering that circuit.
· The anti-lock brake control module then looks at the anti-lock brake sensor signal from the affected wheel again.
· If that wheel is still decelerating, it opens the solenoid valve for that circuit.
· Once the affected wheel comes back up to speed, the anti-lock brake control module returns the solenoid valves to their normal condition allowing fluid flow to the affected brake.
· The anti-lock brake control module monitors the electromechanical components of the system.
· Malfunction of the anti-lock brake system will cause the anti-lock brake control module to shut off or inhibit the system. However, normal power-assisted braking remains.
· Loss of hydraulic fluid in the brake master cylinder will disable the anti-lock system.
· The 4-wheel anti-lock brake system is self-monitoring. When the ignition switch is turned to the RUN position, the anti-lock brake control module will perform a preliminary self-check on the anti-lock electrical system indicated by a three second illumination of the yellow ABS wanting indicator.
· During vehicle operation, including normal and anti-lock braking, the anti-lock brake control module monitors all electrical anti-lock functions and some hydraulic operations.
· Each time the vehicle is driven, as soon as vehicle speed reaches approximately 20 km/h (12 mph), the anti-lock brake control module turns on the pump motor for approximately one-half second. At this time, a mechanical noise may be heard. This is a normal function of the self-check by the anti-lock brake control module.
· When the vehicle speed goes below 20 km/h (12 mph), the ABS turns off.
· Most malfunctions of the anti-lock brake system and traction control system, if equipped, will cause the yellow ABS warning indicator to be illuminated.

Traction control
The ABS equipment may also be used to implement traction control system (TCS, ASR) on acceleration of the vehicle. If, when accelerating, the tire loses traction, the ABS controller can detect the situation and take suitable action so that traction is regained. Manufacturers often offer this as a separately priced option even though the infrastructure is largely shared with ABS. More sophisticated versions of this can also control throttle levels and brakes simultaneously.
Mercedes-Benz was the first to offer this electronic traction control system in 1985.

ENGINE CYLINDER LINER TECHNOLOGY

Technical data: These Cylinder Liners are manufactured from special quality close Grained alloyed cast iron, which is centrifugally cast after melting it in Inductotherm Induction Furnace.
MICROSTRUCTURE: The microstructure obtained is pearlitic, with uniform distribution of graphite flakes. The percentage of ferrite is less than 5 %.
Hardness: 200BHN TO 220BHN
Chemical composition: Constituents % Of Material Composition Carbon : 3.0 - 3.4 Silicon : 1.8 -2.4 Manganese : 0.6 -0.8 Phosphorous : 0.4 -0.7 Chromium : 0.1- 0.3
Liner types: There are two types of cyllinder liners i.e. DRY and WET type Liners.( Dry liners do not interface with water coolant where as wet type do). Wet liners are generally flanged type. Dry liners may be plain or flanged. Salient features: Excellent wear resistance qualities Adequate toughness Provides excellent lubrication even in dry running conditions due to the Evenly spread flakes in the structure. Able to transmit heat faster from combustion process to coolant. Superb oil absorbing and retaining capability.
Range : These liners are available in the range of 50 mm to 150mm dia and length upto 300mm.

Apollo Tjaarda tyres

Apollo Tjaarda tyres launched at Auto Expo

Till recently, he was known as an ace car designer. Tom Tjaarda, who has designed more than 70 cars, has found a new field of interest ? tyres. Tjaarda has reportedly designed concept tyres for the Apollo group.
Called the Apollo Aspire TT, the tyres are currently on display at the ninth Auto Expo being held in New Delhi. According to Apollo Tyres, the Aspire TT combines the inherent strengths of performance and safety. The tyre combines a bidirectional asymmetric tread pattern, created for greater grip, maneuvering and comfort.
Apollo is looking keenly at the segment of concept tyres for the development of future products. Apart from the Aspire TT, another Tjaarda-designed tyre concept is also on display. Brand-named Dolphin, it is supposedly very effective on wet surfaces, with an aggressive off-shoulder for performance on uneven surfaces. The two concepts are seen as Apollo Tyres? demonstration of its ability to deliver on the various aspects of design and technology.
The two tyre concepts are expected to hit the market later in 2008. The Apollo pavilion also showcases the company?s product range including the two successful brands such as Apollo and Regal. These apart, high-speed passenger radial and 4x4 ranges - both summer and winter tyres, commercial vehicle radials and cross-ply and OTR tyres are also on show.
Apollo has posted revenues of over $1 billion and has four manufacturing units in India. Its' overseas presence translates into two manufacturing units in South Africa and two more in Zimbabwe. In South Africa, it has over 900 dealerships, of which 190 are Dunlop Accredited Dealers.

ashley's i-bus

Ashok Leyland iBus to cost Rs 60 lakh


Ashok Leyland has launched iBus, its low-floor concept bus at the Auto Expo 2008. Priced at Rs 60 lakh, the iBus is a 1.5-metre low-floor bus, also believed to be the widest vehicle in the country. The iBus employs GPS technology that enables vehicle tracking and displays route information on an LCD screen.
The iBus also provides passenger infotainment with user-friendly message and news. Other features of the iBus include an anti-lock braking system (ABS), electronic engine management, and an elegantly designed VIP enclosure, complete with Internet access.
Experts believe that the new low floor buses currently on display could provide commuters with a safer travel option, not just in New Delhi, but everywhere in the country.
The Delhi administration is planning to float tenders for buses to help it tide over the public transportation crisis. Ashok Leyland is expected to bid for the next tender for low-floor buses from the Delhi Transport Corporation. Leyland is also expected to bid for the second and third tender of the DTC for about 3,500 buses.
The Delhi Transport Corporation plans to bring in as many as an 8,000 buses to its fleet before the 2010 Commonwealth Games. This initiative is expected to cost Rs 4000 crore for the Corporation.
Ashok Leyland is gearing up to sell as many as 100-150 iBUSes in the next fiscal.

Air cushion vehicles (ACV)

In the world of crafts Air cushion vehicles (ACV) are fast catching up. Air cushion vehicle is a craft that travels on a layer of compressed air just above any kind of surface- land, water, ice etc. Their main area of applications are in military vehicles, helicopters and where transportation using wheeled or tracked vehicles are impossible. Air cushion vehicle (ACV) is a craft that travels on a layer of compressed air just above any kind of surface – land, water, ice, sand, mud etc. The compressed air serves as an invisible cushion that eliminates almost all friction between the vehicle and the surface. Air cushion vehicles are also known as Hovercraft. They can carry both passenger and freight. Some air cushion vehicles can travel as fast as 480 km per hour.

USE OF RINGS & SIGNIFICANCE OF GAP

USE OF RINGS & SIGNIFICANCE OF GAP

Sometimes the best solutions are deceptively simple. Take, for example, sealing the combustion chamber in an internal combustion engine. Extreme temperatures mean pretty significant expansion rates when it comes to moving components within an engine and the exacting tolerances required to make that engine work properly. It gets worse when you mix metals that have different expansion rates, which is exactly what happens when you have an aluminum piston traveling inside a cast-iron cylinder bore. Leave enough tolerance between the piston and cylinder when it's hot, and it will never seal well enough to even start when it's cold. Tighten up the tolerances enough to achieve a cold start, and the engine tears itself apart from the inside out before you can even get the car on the track.

The top ring is the most important. It provides the seal that is used to create compression, hold the burning-and rapidly expanding-air/fuel mixture in the combustion chamber on the power stroke, and push the burnt remains of combustion out of the chamber to complete the process. The second ring is a bit of a backup; whatever compression slips past the first ring, the second ring helps to contain. The third ring is commonly referred to as the oil ring. It is actually two scraper rings assembled with a corrugated spacer ring between them. The oil ring's job is to scrape excess oil off the cylinder walls so that it doesn't mix with the air/fuel charge.

IN SHORT

RINGS DO NOT ALLOW THE COMPRESSED MATERIAL TO BY-PASS

AND GAP DO NOT ALLOW THE RING TO STICK..........BY RESEARCH ENGINEER JITESH

latest liner's technology

Ceramic linersCeramic Liners have better performance than metal liners in wear-proof,corrosion resistant and service life. Ceramic liners have reduced the drilling cost and improved the labour intensity in locale .So ceramic liners are the frist choice of upgrade high-voltage mud pump liners.The material of ceramic liner is the most advanced international increased flexible zirconium.The fracture toughness is K 10～15MPa (10 times valve of traditional ceramic),bending strengh is σ 600～800Mpa,Weber coefficient is m18.The specification size is （Φ150～180×310～440mm）.