Showing posts with label Gadget and spare parts. Show all posts
Showing posts with label Gadget and spare parts. Show all posts

Tuesday, October 13, 2009

V8 Engine




The V8 with a crossplane crankshaft (see below) is a very common configuration for large automobile engines. V8 engines are rarely less than 3.0 L (183 cu in) in displacement and in automobile use have gone up to and beyond 8.2 L (500 cu in) in production vehicles. Industrial and marine V8 engines can be much larger.

V8s are generally only standard on more powerful muscle cars, pony cars, sports cars, luxury cars, pickup trucks, and SUVs. However they are often optional on vehicles which have a V6 or straight-6 as standard engine. In many cases, V6 engines were derived from V8 designs by removing two cylinders without changing the V-angle so they can be built on the same assembly lines as the V8s and installed in the same engine compartments with few modifications.

The traditional 90° big-bore V8 engine is generally too wide and too long to fit easily in vehicles with a transverse engine front-wheel drive layout, so its application is mostly limited to rear-wheel drive sports cars, muscle cars, pony cars, luxury cars and light trucks. The shorter and occasionally narrower V6 engine is easier to fit in small engine compartments, but a few compact V8 engines have been used in transverse FWD and transverse AWD engine configurations in larger cars, such as Cadillacs and Volvos. These engines often have tighter cylinder bore spacings, narrower cylinder bank angles, and other modifications to reduce their space requirements.

V8s are common in purpose-designed engines for racing cars. They usually have flat-plane crankshafts, since a crossplane crankshaft results in uneven firing into the exhaust manifolds which interferes with engine tuning, and the heavy crankshaft counterweights prevent the engine from accelerating rapidly. They are a common engine configuration in the highest echelons of motorsport, especially in the USA where it is required in IRL, ChampCar and NASCAR. V8 engines are also used in Australian motorsport, most notably in the V8 Supercars . Formula One began the 2006 season using naturally aspirated 2.4 L (~146 cu in) V8 engines, which replaced the 3.0 L (~183 cu in) V10 in a move to reduce costs and power.

Heavy trucks and railroad locomotives tend to use the straight-6 configuration since it is simpler and easier to maintain, and since the straight-6 is an inherently balanced layout which can be scaled up to almost any size necessary. Large V8s are found in the larger truck and industrial equipment lines, however.

Although it was an early choice for airplane engines, the V8 engine is seldom used in modern aircraft engine since the typically heavy crankshaft counterweights are a liability. Modern light planes commonly use the flat-8 configuration instead since it is lighter and easier to air cool, in addition to which it can be manufactured in modular designs sharing components with flat-4 and flat-6 engines.


from: wikipedia

Thursday, December 18, 2008

Intercooler?



An intercooler, or charge air cooler, is an air-to-air or air-to-liquid heat exchange device used on turbocharged and supercharged (forced induction) internal combustion engines to improve their volumetric efficiency by increasing intake air charge density through isochoric cooling. A decrease in air intake temperature provides a denser intake charge to the engine and allows more air and fuel to be combusted per engine cycle, increasing the output of the engine.

The inter prefix in the device name originates from historic compressor designs. In the past, aircraft engines were built with charge air coolers that were installed between multiple stages of supercharging, thus the designation of inter. Modern automobile designs are technically designated aftercoolers because of their placement at the end of supercharging chain. This term is now considered archaic in modern automobile terminology since most forced induction vehicles have single-stage superchargers or turbochargers. In a vehicle fitted with two-stage turbocharging, it is possible to have both an intercooler (between the two turbocharger units) and an aftercooler (between the second-stage turbo and the engine). The JCB Dieselmax land speed record-holding car is an example of such a system. In general, an intercooler or aftercooler is said to be a charge air cooler.

Intercoolers can vary dramatically in size, shape, and design, depending on the performance and space requirements of the entire supercharger system. Common spatial designs are front mounted intercoolers (FMIC), top mounted intercoolers (TMIC), hybrid mount intercoolers (HMIC). Each type can be cooled with an air-to-air system, air-to-liquid system, or a combination of both.
Many older turbo-charged cars, such as the Toyota Supra (JZA80 only), Nissan 300ZX Twin Turbo, Nissan 200SX (S13/14/14a/15), Mitsubishi 3000gt, Saab 900, Volkswagen, Audi TT, and Turbo Mitsubishi Eclipse use side-mounted air-to-air intercoolers (SMIC), which are mounted in the front corner of the bumper or in front of one of the wheels. Side-mounted intercoolers are generally smaller, mainly due to space constraints, and sometimes two are used to gain the performance of a larger, single intercooler. Cars such as the Subaru Impreza WRX, MINI Cooper S, Toyota Celica GT-Four, Nissan Pulsar GTI-R, MAZDASPEED3, MAZDASPEED6 and the PSA Peugeot Citroën turbo diesels, use air-to-air top mounted intercoolers (TMIC) located on top of the engine. Air is directed through the intercooler through the use of a hood scoop. In the case of the PSA cars the air intake is the grille above the front bumper, then flows through under-hood ducting. Top mounted intercoolers sometimes suffer from heat diffusion due to proximity with the engine, warming them and reducing their overall efficiency. Some World Rally Championship cars use a reverse-induction system design whereby air is forced through ducts in the front bumper to a horizontally-mounted intercooler.


from: wikipedia.org

Wednesday, December 10, 2008

Global Positioning System for Car



The Global Positioning System (GPS) is a Global Navigation Satellite System (GNSS) developed by the United States Department of Defense. It is the only fully functional GNSS in the world. It uses a constellation of between 24 and 32 Medium Earth Orbit satellites that transmit precise microwave signals, which enable GPS receivers to determine their current location, the time, and their velocity. Its official name is NAVSTAR GPS. Although NAVSTAR is not an acronym, a few backronyms have been created for it. The GPS satellite constellation is managed by the United States Air Force 50th Space Wing. GPS is often used by civilians as a navigation system.

After Korean Air Lines Flight 007 was shot down in 1983 after straying into the USSR's prohibited airspace, President Ronald Reagan issued a directive making GPS freely available for civilian use as a common good. Since then, GPS has become a widely used aid to navigation worldwide, and a useful tool for map-making, land surveying, commerce, scientific uses, and hobbies such as geocaching. Also, the precise time reference is used in many applications including the scientific study of earthquakes. GPS is also a required key synchronization resource of cellular networks, such as the Qualcomm CDMA air interface used by many wireless carriers in a multitude of countries.

The first satellite navigation system, Transit, used by the United States Navy, was first successfully tested in 1960. Using a constellation of five satellites, it could provide a navigational fix approximately once per hour. In 1967, the U.S. Navy developed the Timation satellite which proved the ability to place accurate clocks in space, a technology that GPS relies upon. In the 1970s, the ground-based Omega Navigation System, based on signal phase comparison, became the first worldwide radio navigation system. The design of GPS is based partly on similar ground-based radio navigation systems, such as LORAN and the Decca Navigator developed in the early 1940s, and used during World War II. Additional inspiration for the GPS came when the Soviet Union launched the first Sputnik in 1957. A team of U.S. scientists led by Dr. Richard B. Kershner were monitoring Sputnik's radio transmissions. They discovered that, because of the Doppler effect, the frequency of the signal being transmitted by Sputnik was higher as the satellite approached, and lower as it continued away from them. They realized that since they knew their exact location on the globe, they could pinpoint where the satellite was along its orbit by measuring the Doppler distortion.

from :wikipedia.org



Monday, September 29, 2008

Car key


A car key or an automobile key is a key used to open and/or start an automobile, often identified with the logo of the car company at the head. Modern key designs are usually symmetrical, and some use grooves on both sides, rather than a cut edge, to actuate the lock. It has multiple uses for the automobile with which it was sold. A car key can open the doors, as well as start the ignition, open the glove compartment and also open the trunk (boot) of the car. Some cars come with an additional key known as a valet key that starts the ignition and opens the drivers side door but prevents the valet from gaining access to valuables that are located in the trunk or the glove box. Some valet keys, particularly those to high-performance vehicles, go so far as to restrict the engine's power output to prevent joyriding.[1] Recently, features such as coded immobilizers have been implemented in newer vehicles. More sophisticated systems make ignition dependent on electronic devices, rather than the mechanical keyswitch. Ignition switches/locks are combined with security locking of the steering column (in many modern vehicles) or the gear lever (Saab Automobile). In the latter, the switch is between the seats, preventing damage to the driver's knee in the event of a collision.

Keyless entry systems, which utilize a remote control in place of a car key, are becoming a standard feature on many new cars. Some of them are handsfree.

Switchblade key from a 2005 Land Rover LR3.
Switchblade key from a 2005 Land Rover LR3.
Some keys are high-tech in order to prevent the theft of a car. Mercedes-Benz uses a key that, rather than have a cut metal piece to start the car, uses an encoded infrared beam that communicates with the car's computer. If the codes match, the car can be started. These keys can be expensive to replace, if lost, and can cost up to US$400. Some car manufacturers like Land Rover and Volkswagen use a 'switchblade' key where the key is spring-loaded out of the fob when a button is pressed. This eliminates the need for a separate key fob. This type of key has also been known to be confiscated by airport security officials.

from:http://wikipedia.org