Anti-lock braking system

An anti-lock braking system (ABS) is a safety system that allows the wheels on a motor vehicle to continue interacting tractively with the road surface as directed by driver steering inputs while braking, preventing the wheels from locking up (that is, ceasing rotation) and therefore avoiding skidding.

An ABS generally offers improved vehicle control and decreases stopping distances on dry and slippery surfaces for many drivers; however, on loose surfaces like gravel or snow-covered pavement, an ABS can significantly increase braking distance, although still improving vehicle control.[1]

Since initial widespread use in production cars, anti-lock braking systems have evolved considerably. Recent versions not only prevent wheel lock under braking, but also electronically control the front-to-rear brake bias. This function, depending on its specific capabilities and implementation, is known as electronic brakeforce distribution (EBD), traction control system, emergency brake assist, or electronic stability control (ESC).

Early systems

The ABS was first developed for aircraft use in 1929 by the French automobile and aircraft pioneer, Gabriel Voisin, as threshold braking on airplanes is nearly impossible. An early system was Dunlop's Maxaret system, which was introduced in the 1950s and is still in use on some aircraft models.[2] These systems use a flywheel and valve attached to a hydraulic line that feeds the brake cylinders. The flywheel is attached to a drum that runs at the same speed as the wheel. In normal braking, the drum and flywheel should spin at the same speed. However, if a wheel were to slow down, then the drum would do the same, leaving the flywheel spinning at a faster rate. This causes the valve to open, allowing a small amount of brake fluid to bypass the master cylinder into a local reservoir, lowering the pressure on the cylinder and releasing the brakes. The use of the drum and flywheel meant the valve only opened when the wheel was turning. In testing, a 30% improvement in braking performance was noted, because the pilots immediately applied full brakes instead of slowly increasing pressure in order to find the skid point. An additional benefit was the elimination of burned or burst tires.[3]

In 1958, a Royal Enfield Super Meteor motorcycle was used by the Road Research Laboratory to test the Maxaret anti-lock brake.[4] The experiments demonstrated that anti-lock brakes can be of great value to motorcycles, for which skidding is involved in a high proportion of accidents. Stopping distances were reduced in most of the tests compared with locked wheel braking, particularly on slippery surfaces, in which the improvement could be as much as 30 percent. Enfield's technical director at the time, Tony Wilson-Jones, saw little future in the system, however, and it was not put into production by the company.[4]

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 unreliable in automobile use.
[edit] Modern systems

Chrysler, together with the Bendix Corporation, introduced a computerized, three-channel, four-sensor all-wheel ABS called "Sure Brake" for its 1971 Imperial.[5] It was available for several years thereafter, functioned as intended, and proved reliable. In 1971, General Motors introduced the "Trackmaster" rear-wheel only ABS as an option on their Rear-wheel drive Cadillac models.[6][7] In the same year, Nissan offered an EAL (Electro Anti-lock System) as an option on the Nissan President, which became Japan's first electronic ABS.[8]

In 1975, Robert Bosch took over the European company Teldix and all patents registered by the joint-venture and used this acquisition to build the base of the ABS introduced on the market some years later.

Air Conditioners System

Air Conditioners Flow System

In order to understand, how the car air conditioning system operates, it is required to know various parts of this unit. First of all, the most important component which is present in this system is the compressor. The compressor is the central component which emits hoses of both high and low pressures. When these hoses come out, they go inside the condenser and finally to the evaporator. In this system, there are two types of valves like expansion and dryer valves, which are required for the proper functioning of this system. The function of expansion valves is to regulate the internal temperature of air, and it controls the refrigerant flow inside the system. There are certain anti-freezing agents as well like coolant or condensed gases, which pass through these valves.

The mechanism of a car air conditioning system is quite different from the conventional air conditioners. The car system instead of making the air cool, take out the heat, which is already found in the air. The Freon gas is used in the car air conditioning system which possesses a high temperature. When this gas passes through the compressor, the pressure channels mix it with the fresh air. The total gas mixture due to compression becomes liquid, and then it comes to the dryer. This chamber purifies the gas and sends to the evaporator through an expansion valve. The liquid gas absorbs the heat of the car which is then evaporated from here by the help of a blower or fan. This phenomenon repeats several times in order to make the environment cooler.

If you got certain problems in the car air conditioning system then you need to call a mechanic, since the fixing of this system is not a simple job. However; you can avoid the development of various problems in this system and hence can escape from big hassles. It is better to check the leakage of the car air conditioning system on a regular basis. Leakage takes out all the gas present inside the air conditioner and hence with the passage of time, the system becomes useless. It is also good to check the compressor regularly. It could be done by turning on the car followed by switching on the air conditioner. After that, lift up the bonnet and identify the compressor. If there is no movement in the compressor, it means there is some problem in the switching system. Sometimes refrigerant creates problems like the cooling does not happen in the opened system. If such types of problems are identified, call immediately to an electrician or a mechanic.

Four Wheel

There are almost as many different types of four-wheel-drive systems as there are four-wheel-drive vehicles. It seems that every manufacturer has several different schemes for providing power to all of the wheels. The language used by the different carmakers can sometimes be a little confusing, so before we get started explaining how they work, let's clear up some terminology:

* Four-wheel drive - Usually, when carmakers say that a car has four-wheel drive, they are referring to a part-time system. For reasons we'll explore later in this article, these systems are meant only for use in low-traction conditions, such as off-road or on snow or ice.
* All-wheel drive - These systems are sometimes called full-time four-wheel drive. All-wheel-drive systems are designed to function on all types of surfaces, both on- and off-road, and most of them cannot be switched off.

Part-time and full-time four-wheel-drive systems can be evaluated using the same criteria. The best system will send exactly the right amount of torque to each wheel, which is the maximum torque that won't cause that tire to slip.

In this article, we'll explain the fundamentals of four-wheel drive, starting with some background on traction, and look at the components that make up a four-wheel-drive system. Then we'll take a look at a couple of different systems, including the one found on the Hummer, manufactured for GM by AM General.

We need to know a little about torque, traction and wheel slip before we can understand the different four-wheel-drive systems found on cars.

Rear wheel

Rear Wheel Drive Cars
There are many benefits of rear wheel drive cars, but these come at a cost of driver safety. Experienced drivers do not face these problems though, and the number of people that prefer rear wheel drive cars is constantly rising today.
Rear Wheel Drive Cars
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Most of the automobiles that are prevalent in the market today are manufactured with front wheel drives (FWD). This is a trend that has risen towards the end of the 20th century, as most cars of the 20th century were manufactured with rear wheel drives (RWD). There are plenty of reasons for this paradigm shift from FWD cars to rear wheel drive cars, but in the last couple of years, car manufacturers are shifting towards rear wheel drive cars once again. Read more about the history of cars.

The primary difference between FWD cars and rear wheel drive cars is the set of wheels that the engine controls. In RWD cars the engine is placed at the front end of the car, and the set of wheels that are powered by the engine are the rear wheels. This layout is commonly referred to as the front-engine rear-wheel drive layout, or the FR layout. Any motorcycle that you see on the road follows this layout, as it is the rear wheels that are powered by the engine. Read more about the various car parts.

Emergence of FWD Cars
There are plenty of reasons why rear wheel drive cars were replaced by front wheel drive cars, and the primary reason was that of car safety. Car manufacturers and drivers began to realize that the driving experience can be much safer if the car is fitted with a front wheel drive. The majority of the weight of the car is on the front wheels in the front wheel drive, and as a result of this the car tends to go straight, similar to an arrowhead that places the head at the front tip of the shaft. It still holds true that if a car skids or goes out of control, a front wheel drive enables the driver to regain control of the car easier and faster, thus avoiding car crashes. If a person does not know how to drive rear wheel drive cars properly, there's a high chance that he will be unable to regain control of the car if it slides, as at least half of the weight is on the rear side resulting in the car rotating. Learn about other car problems.

Despite these obvious safety concerns, most luxury cars, and even racing cars for that matter are endowed with rear wheel drives. The explanation for this is that since the weight of the car is almost equally distributed between the front and the back, there is greater balance while the car is in motion. This makes the car easier to handle, and lends a dynamism to its movement that cannot be experienced with front wheel drive cars. If the car needs to be stopped suddenly, rear wheel drive cars are far more superior to FWD cars as well. Read more on automobile safety ratings.

Disadvantages of Rear Wheel Drive Cars
Many car enthusiasts are firmly against RWD cars, and point out the following reasons for their inherent dislike of such vehicles.

* Since the engine is in the front, the transmission shaft that connects to the rear wheels have to travel under the entire length of the car's body. This increases the overall weight of the vehicle.
* Only someone who knows how to drive rear wheel drive cars can handle the vehicle effectively. Average drivers find it difficult to maneuver these cars.
* These cars are more expensive than FWD cars. This is due to the higher cost of assembly, owing to the presence of a long transmission tunnel that connects the engine to the rear wheels.
* On wet surfaces like snow, rain, gravel etc. these cars are tougher to navigate, as the car is being powered from behind, like a push, vis a vis a FWD car, where the engine acts like it is pulling a vehicle.
* Many people also complain about the lack of interior space and leg room in RWD car. This is again due to the presence of the transmission tunnel under the body of the car, running from the engine to the rear wheels.

Advantages of Rear Wheel Drive Cars
Along with these factors, there are other reasons why many people prefer to drive RWD cars.

* Since all the auto parts are spread out over a wide area, the repair and maintenance costs of RWD cars are relatively lower. Their repair does not require complicated disassembly and uses lesser specialized tools.
* Since the front wheels are concentrating on the steering, more power can be applied to the rear wheels and the vehicle on a whole under dry conditions. Since the force is lesser on the front wheels, more friction can be utilized towards steering.
* Under heavy and sudden braking, the car stops smoothly since the weight is evenly divided between the front and the rear of the vehicle.
* There is no presence of 'torque steer' in RWD cars, vis a vis FWD cars. The presence of this effect in FWD cars causes the car to shift slowly towards the right side at high speeds, owing to the difference in length of the shafts that connect the engine to the wheels.

How to Drive a Rear Wheel Drive Car in Snow
Driving rear wheel drive car in snow is a skill that can be acquired only through practice and caution. It is definitely more dangerous to drive a RWD car in snow than a FWD car, but for someone who is aware of how to drive rear wheel drive cars, this is no big feat. Just adhere to the following guidelines and you will do just alright.

Front-wheel

The vast majority of front-wheel drive vehicles today use a transversely mounted engine with "end-on" mounted transmission, driving the front wheels via driveshafts linked via constant velocity (CV) joints. This configuration was made popular by the 1967 Simca 1100,[2] and the 1969 Fiat 128.[citation needed] The 1959 Mini, while a pioneering transverse front-wheel drive vehicle[citation needed], used a substantially different arrangement with the transmission in the sump.

Volvo Cars has switched its entire lineup after the 900 series to front wheel drive. Swedish engineers at the company have said that transversely mounted engines allow for more crumple zone area in a head on collision. American auto manufacturers are now shifting larger models (such as the Chrysler 300 and most of the Cadillac lineup) back to rear-wheel drive.[3][4] There were relatively few rear-wheel drive cars marketed in North America by the early 1990s; Chrysler's car line-up was entirely front-wheel drive by 1990. GM followed suit in 1996 where its B-body line was phased out, where its sports cars (Camaro, Firebird, Corvette) were the only RWDs marketed; by the early 2000s, the Chevrolet Corvette was the only RWD car offered by Chevrolet until the introduction of the Sigma platform.
[edit] Records

Supercharger

Supercharger Basics

A basic engine with the addition of a supercharger.

An ordinary four-stroke engine dedicates one stroke to the process of air intake. There are three steps in this process:

1. The piston moves down.
2. This creates a vacuum.
3. Air at atmospheric pressure is sucked into the combustion chamber.

Once air is drawn into the engine, it must be combined with fuel to form the charge -- a packet of potential energy that can be turned into useful kinetic energy through a chemical reaction known as combustion. The spark plug initiates this chemical reaction by igniting the charge. As the fuel undergoes oxidation, a great deal of energy is released. The force of this explosion, concentrated above the cylinder head, drives the piston down and creates a reciprocating motion that is eventually transferred to the wheels.

Getting more fuel into the charge would make for a more powerful explosion. But you can't simply pump more fuel into the engine because an exact amount of oxygen is required to burn a given amount of fuel. This chemically correct mixture -- 14 parts air to one part fuel -- is essential for an engine to operate efficiently. The bottom line: To put in more fuel, you have to put in more air.

That's the job of the supercharger. Superchargers increase intake by compressing air above atmospheric pressure, without creating a vacuum. This forces more air into the engine, providing a "boost." With the additional air in the boost, more fuel can be added to the charge, and the power of the engine is increased. Supercharging adds an average of 46 percent more horsepower and 31 percent more torque. In high-altitude situations, where engine performance deteriorates because the air has low density and pressure, a supercharger delivers higher-pressure air to the engine so it can operate optimally.

Unlike turbochargers, which use the exhaust gases created by combustion to power the compressor, superchargers draw their power directly from the crankshaft. Most are driven by an accessory belt, which wraps around a pulley that is connected to a drive gear. The drive gear, in turn, rotates the compressor gear. The rotor of the compressor can come in various designs, but its job is to draw air in, squeeze the air into a smaller space and discharge it into the intake manifold.

Turbo

DESIGN assumptions in
Designs related data before, some problems to be encountered will be emphasized.

Excessive Pressure
Turbo piston by the compressed air sent to the next stage more compressed by the piston to create an extreme pressure. This may heat the gas pressure (as warming occurs at high pressure thermodynamics), firing may take time before the fire. An event that causes a knock at the Buddha. Turbo pressure to reduce or prevent high-octane gasoline to use it.

Knock: Tapping; knock work with; unhealthy time of combustion-exhaust.

Turbo Time
Often, small-size turbo-equipped vehicles, acceleration does not respond instantly to commands sudden gas accumulation is seen. This slow development of the turbine can be caused by movement of the spinel. After a certain period began to run turbo (2000-2500 d / d), sudden gas start to run commands with a delay of 1-2 seconds and the car goes akselerasyona. Undesirable because of this delay is the weight of the turbine part, because a heavy need more power to turn the propeller. Yokedilemez delay completely, but parts made of lighter materials highly reduced.



Large - Small Turbocharger Comparison: Small volume applications turbo turbo lag is not open on time for the recording will be working and lower engine speeds. However, at high speed sufficient power production can not occur. In large volume produced more power at higher speeds, better acceleration values to obtain the delay time can not be prevented, but because in a larger size turbines and pumps are used. The method will be reviewed to eliminate it.

Turbine valve: This valve, the exhaust gas to evacuate more pressure adjusts the operation of the turbines. Turbines in a different way egzosta output is transferred to.
Bearings: bearings used herein, except in exceptional application is used as fat deposits. But they are special and lightweight materials are made of. Abrasion, corrosion, heat resistance is good.
Ceramics for Turbine Extended: Ceramic material is lighter than conventional metal materials has a structure. Abrasion resistance is also very high. Moreover, there are advantages to be used at high temperatures. Because ceramic is much higher than metal softening and melting temperature have. This material as a ceramic turbine makes use of important.
Dual turbocharger applications: In some cases, used for small turbo at low revs on acceleration as well as high speeds due to the insufficient large turbo is added.