The Parts Of A Crawler-Based Search Engine

Crawler-based search engines have three major elements. First is the spider, also called the crawler. The spider visits a web page, reads it, and then follows links to other pages within the site. This is what it means when someone refers to a site being "spidered" or "crawled." The spider returns to the site on a regular basis, such as every month or two, to look for changes.
Everything the spider finds goes into the second part of the search engine, the index. The index, sometimes called the catalog, is like a giant book containing a copy of every web page that the spider finds. If a web page changes, then this book is updated with new information.
Sometimes it can take a while for new pages or changes that the spider finds to be added to the index. Thus, a web page may have been "spidered" but not yet "indexed." Until it is indexed -- added to the index -- it is not available to those searching with the search engine.

Search engine software is the third part of a search engine. This is the program that sifts through the millions of pages recorded in the index to find matches to a search and rank them in order of what it believes is most relevant. You can learn more about how search engine software ranks web pages on the aptly-named How Search Engines Rank Web Pages page.

hybrid

Most of these involve the coupling of an engine, an electric motor and sometimes batteries, in various different ways to allow excess energy that would otherwise have been lost, to be stored in the vehicle. Energy is created by activities such as braking and descending hills, or by running the engine at its most efficient while the stored electrical energy takes up the variations in required power. This can improve the vehicle efficiency and fuel consumption dramatically. Many manufacturers are running development work on such systems. So far hybrids are more expensive and heavier than normal engines but offer the chance to downsize to obtain the same power. This type of system is also likely to drive the need for more efficient turbochargers.

Hybrid engines.

Double the gains: the intelligent combination of a combustion engine and electric motors aims to save fuel and reduce emissions, while simultaneously improving dynamic performance and driving comfort.

Hybrid comes from the Latin and describes something of mixed origin or comprising different elements. With reference to vehicles, it denotes one that uses two different drive systems - generally a combination of a combustion engine and an electric motor. In a mild hybrid, the electric motor only assists the internal combustion engine. In a full hybrid, an internal combustion engine is combined with a relatively large electric motor. This motor is powerful enough to drive the car on its own, at low speeds.
For BMW, the term hybrid represents something more than simply integrating an electric motor. It represents the intelligent management of energy flows within the vehicle. Modern hybrid drives aim to save fuel and reduce emissions, while simultaneously improving dynamic performance. Based on a modular hybrid drive system, optimally chosen hybrid components are integrated into each vehicle so that they can be used as and when they are needed. BMW ActiveHybrid represents all future BMW hybrid technologies and plays a major role in BMW EfficientDynamics.

Hybrid electric vehicle

A hybrid electric vehicle (HEV) is a type of hybrid vehicle and electric vehicle which combines a conventional internal combustion engine (ICE) propulsion system with an electric propulsion system. The presence of the electric powertrain is intended to achieve either better fuel economy than a conventional vehicle, or better performance. A variety of types of HEV exist, and the degree to which they function as EVs varies as well. The most common form of HEV is the hybrid electric car, although hybrid electric trucks (pickups and tractors) and buses also exist.

Modern HEVs make use of efficiency-improving technologies such as regenerative braking, which converts the vehicle's kinetic energy into battery-replenishing electric energy, rather than wasting it as heat energy as conventional brakes do. Some varieties of HEVs use their internal combustion engine to generate electricity by spinning an electrical generator (this combination is known as a motor-generator), to either recharge their batteries or to directly power the electric drive motors. Many HEVs reduce idle emissions by shutting down the ICE at idle and restarting it when needed; this is known as a start-stop system. A hybrid-electric produces less emissions from its ICE than a comparably-sized gasoline car, since an HEV's gasoline engine is usually smaller than a comparably-sized pure gasoline-burning vehicle (natural gas and propane fuels produce lower emissions) and if not used to directly drive the car, can be geared to run at maximum efficiency, further improving fuel economy.

The Cost of Hybrid Cars

Hybrid-engineered cars cost a bit more too. Usually the price difference is around 3,000 bucks. And, it may take a few years (depending on gas prices) for you to actually make the savings in fuel worthwhile. However, it's still better for the environment, and that lingers (and makes it worthwhile) in some consumers' minds.

And, if you are still one to wholeheartedly grip the stick of your V-8 without budging, you might take into mind that newer hybrid models are gaining on those petal-to-the-metal peelers of yesteryear. Hybrid models are inching nearer to (and even beating!) gas powered cars in 0 to 60 mph road tests.
So, when you decide that a new car might be a viable option in the near future, don't expect to see too many hybrids in dealers' lots. You may have to do some across-the-state driving to find a choice. Do some preliminary searching on the Internet and find out what model may benefit you and your lifestyle the most. Keep in mind all that we've mentioned and perhaps-in the future-you'll have no other choice than a hybrid, which at this time seems to be by far the best choice around.

Read more: Hybrid Engines - A Brief Description of Hybrid Engines and their Benefits
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Small Price Hike

The second hybrid is often referred to as a series hybrid. In a series hybrid, the gas or diesel powered engine doesn't connect to the transmission directly, meaning that it doesn't actually propel the car by itself. It actually works indirectly, powering a generator, which in turn (controlled by computer monitoring systems) either feeds power to the batteries or directly feeds power to an electric motor that connects to the transmission.
As stated above, hybrid buyers are looking for the combination (and compromise) of power and energy that these cars seem to provide. Many gas-powered cars have a lot of horsepower. This is useful for modern driving experiences. No one wants to be doing the minimum 45 mph on the interstate and stopping to "refuel," as with purely electric motors. Plus, there's no need to feel like you should have placed your slow-moving reflective magnet on the trunk. However, many gas-powered cars are truly "wasteful" resources because out of those 175 horses, you'll only have to use less than half that power for everyday driving. We don't even have to get into the harmful environmental factors of pure gasoline engines. We are just now starting to see the results of our apathetic attitudes on this subject.
The engines in hybrid automobiles are usually much smaller (except in some brand new V-6 models). While this reduces fuel consumption, it means that for the extra "power" that drivers are looking for has to come from somewhere else. That's where the electric motor and batteries come into play. In some models, sensors detect that the car is in need of extra energy for going up hill, for example. That's when the "hybrid" half of the engine kicks in. It will do a dandy job of giving the engine that extra oomph or boost that it needs, without using any more gasoline.
Newer hybrid models do a lot of extra tricks so that your car gets as many miles to the gallon as possible. For example, when you're stopped at a traffic light, another sensor will trigger the gasoline engine to idle down to a complete stop, while the car stays "running" solely on its electric power. Did I mention ingenious?
Since the idea behind the hybrid powered car is reduced fuel consumption without the loss of speed or power, many cars are being designed to move through the streets with the utmost in aerodynamic form; meaning that a hybrid will create less "drag," simply due to its body structure. Many also use much lighter building materials, reducing weight and pull. Some models even have wheel covers and no mirrors (replaced with cameras and navigation equipment), which saves an enormous amount of energy.
Hybrids don't seem to be a fad or some social experiment. Consumers and car enthusiasts alike are enjoying what they're seeing in the market. Everyday it seems a better designed, lighter; more fuel-efficient and powerful hybrid enters. Recently released models are even beating their gas-powered counterparts. One boasts a 255 hp engine with other capabilities such as being able to shut down half the cylinders (without notice) while in motion to conserve fuel and energy.

Read more: Hybrid Engines - A Brief Description of Hybrid Engines and their Benefits
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Hybrid Hype and a Small Price Hike

Drive by any car lot in the United States and ask to see the latest hybrid car models. Don't be stupefied if eight out of ten tell you that they can't seem to keep them on the lot-that they're just selling too fast! There is reasoning behind the hype: consumers believe in one (or all) of three things, that they're going to be getting a better deal once gas prices hit $2.50 a gallon, that they're not sacrificing performance and that they're helping the environment.
Let's first take a look at how these cars are put together. First, we have to understand the concept of "hybrid". A hybrid car might be defined as any vehicle that uses two or more sources of energy to propel itself. Seems simple enough. Hybrid machinery is all around us in the form of diesel-electric, such as city buses, and nuclear-electric, such as those used on many US submarines. So, the idea and the technology have been around awhile-it's just now that another energy scare like that of the 1970s, that we start becoming resourceful and a little ingenious. Hybrid power is on the up-rise (and in-demand) only because the two different types of propulsion possibilities (gasoline/diesel and electric) standing alone have proven an ineffective means to get both power and efficiency in one package. But, working together, there is promise.

Read more: Hybrid Engines - A Brief Description of Hybrid Engines and their Benefits
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hybrid cars to plug-ins

 

Typically, in a full hybrid, the electric engine takes control when the car is cruising, at stop, or when slowly accelerating. When extra power is needed, the gas engine kicks in to give the acceleration expected from today's cars. By allowing the electric engine to take over, hybrids are able to get higher mpg than their sister cars with gas only engines. But since most of the energy is collected/saved when the car is stopped or in braking, hybrid cars tend to get better mileage in city driving. Which is opposite what gas only cars should expect, as gas engines are most efficient at high speeds (highway).

When comparing hybrid cars to plug-ins, hybrid engines have not only eliminated the need for plugging in, they have also increased the range that is possible.

Hybrid Engines typically

 Hybrid Engines arecc described as engines with two power sources. The most common today is a hybrid gas-electric engine that combines the low pollution output of an electric engine, with the high power output of a gas engine.

There are as many gas-electric engines as there are hybrid cars. Each engine is designed to allow the gas engine and the electric engine to connect to the drive train to power the engine.

The gas engine and the brakes are used to recharge the battery for the electric engine eliminating the need to plug in overnight, as is necessary for a plug in electric only engine. When braking, some of the energy being expended to stop a car is collected by the regenerative brakes in an electric engine.

Are All Hybrids Created Equal?

There are several ways in which electric motors and a gas/petrol engine can be combined.

Toyota perfected the series/parallel or "full" hybrid to deliver the energy-saving benefit of a series hybrid together with the acceleration benefit of a parallel hybrid. Two key technologies — the power split device and sophisticated energy management — make this possible. They constantly optimize the flows of mechanical power and electric power for safe and comfortable vehicle operation at the highest possible efficiency.

gas engines

Typically, in a full hybrid, the electric engine takes control when the car is cruising, at stop, or when slowly accelerating. When extra power is needed, the gas engine kicks in to give the acceleration expected from today's cars. By allowing the electric engine to take over, hybrids are able to get higher mpg than their sister cars with gas only engines. But since most of the energy is collected/saved when the car is stopped or in braking, hybrid cars tend to get better mileage in city driving. Which is opposite what gas only cars should expect, as gas engines are most efficient at high speeds (highway).

When comparing hybrid cars to plug-ins, hybrid engines have not only eliminated the need for plugging in, they have also increased the range that is possible.

Hybrid Engines

Hybrid Engines are typically described as engines with two power sources. The most common today is a hybrid gas-electric engine that combines the low pollution output of an electric engine, with the high power output of a gas engine.

There are as many gas-electric engines as there are hybrid cars. Each engine is designed to allow the gas engine and the electric engine to connect to the drive train to power the engine.

The gas engine and the brakes are used to recharge the battery for the electric engine eliminating the need to plug in overnight, as is necessary for a plug in electric only engine. When braking, some of the energy being expended to stop a car is collected by the regenerative brakes in an electric engine.

diesel-electric

Many people have probably owned a hybrid vehicle at some point. For example, a mo-ped (a motorized pedal bike) is a type of hybrid because it combines the power of a gasoline engine with the pedal power of its rider. In fact, hybrid vehicles are all around us. Most of the locomotives we see pulling trains are diesel-electric hybrids. Cities like Seattle have diesel-electric buses -- these can draw electric power from overhead wires or run on diesel when they are away from the wires. Giant mining trucks are often diesel-electric hybrids. Submarines are also hybrid vehicles -- some are nuclear-electric and some are diesel-electric. Any vehicle that combines two or more sources of power that can directly or indirectly provide propulsion power is a hybrid. Most hybrid cars on the road right now are gasoline-electric hybrids, although French car maker PSA Peugeot Citroen has two diesel-electric hybrid cars in the works. Since gasoline hybrids are the kind you'll find at your local car dealership, we'll focus on those in this article.

hybrid cars

Have you pulled your car up to the gas pump lately and been shocked by the high price of gasoline? As the pump clicked past $20, $30, $40 or even $50, maybe you thought about trading in your car for something that gets better mileage. Or maybe you're worried that your car is contributing to the greenhouse effect.
The auto industry has the technology to address these concerns. It's the hybrid car. There are a lot of hybrid models on the market these days, and most automobile manufacturers have announced plans to manufacture their own versions.
How does a hybrid automobile work? What goes on under the hood to give you 20 or 30 more miles per gallon than the standard automobile? And does it pollute less just because it gets better gas mileage? In this article, we'll help you understand how this technology works, and we'll even give you some tips on how to drive a hybrid car for maximum efficiency.

How Hybrids Work

Hybrid-electric vehicles (HEVs) combine the benefits of gasoline engines and electric motors and can be configured to obtain different objectives, such as improved fuel economy, increased power, or additional auxiliary power for electronic devices and power tools.
Some of the advanced technologies typically used by hybrids include

• Regenerative Braking. The electric motor applies resistance to the drivetrain causing the wheels to slow down. In return, the energy from the wheels turns the motor, which functions as a generator, converting energy normally wasted during coasting and braking into electricity, which is stored in a battery until needed by the electric motor.
• Electric Motor Drive/Assist. The electric motor provides additional power to assist the engine in accelerating, passing, or hill climbing. This allows a smaller, more efficient engine to be used. In some vehicles, the motor alone provides power for low-speed driving conditions where internal combustion engines are least efficient.
• Automatic Start/Shutoff. Automatically shuts off the engine when the vehicle comes to a stop and restarts it when the accelerator is pressed. This prevents wasted energy from idling.

Zastava 750

The Zastava 750 (Застава 750) was a car made by the Yugoslavian car maker Zavod Crvena Zastava. It was a version of the Fiat 600 made under licence from 1965, it was longer in length than the Fiat version. The Zastava 750 has a 767 cc engine and is the smallest car ever made by Zastava. Later on during production, in 1980. the Zastava 850 was introduced, it featured the same body as the Zastava 750 but the engine had a larger capacity. The Zastava 850 is harder to find than the 750 model but both are still widely available in former Yugoslavia (Serbia, Montenegro, Bosnia but very rarely in Croatia, Macedonia and Slovenia).
Zastava 750 is widely known by its nickname "Fića" (Фићa) or "Fićo" (Фићo) in Serbian, Croatian and Bosnian, by "Fičo" or "Fičko" in Slovene and by "Fikjo" (Фиќо) in Macedonian. The nickname "Fića" comes from the main character of a comic published by the newspaper Borba during the first years of the car's production.

Design

The first generation of the Honda Civic Hybrid was based on the seventh generation Honda Civic. It was the first mainstream vehicle from Honda equipped with a gasoline-electric hybrid system and became the second hybrid model of the company after Insight. Model with manual transmission was rated 46 mpg city / 51 mpg highway according to EPA fuel mileage estimates,^[5] about the same combined mileage as for the Toyota Prius, and became the most fuel-efficient five-passenger sedan ever sold in North America at the time.

An electric motor is sandwiched between the gasoline engine and the transmission, providing up to 13 horsepower. The motor also acts as a generator, to recharge the car's nickel-metal hydride battery located between the rear seat and the trunk, and as a starter motor.
The motor in Civic hybrid is about a quarter-inch thicker than that of the Insight. Through improvements to the magnetic coils of the DC brushless motor, it achieves 30 percent greater assisting and regenerative torque than the previous model without increasing the size.

It generates more torque (46 versus 36 pound-feet) than the motor in Insight. The electricity is stored in a battery consisting of 120 1.2-volt Ni-MH D-cells wired in series. The battery can charge and discharge more rapidly and efficiently though the total capacity is reduced from the Insight's (6.0 versus 6.5 AH). Efficiency of the battery modules is increased, through a reduction in energy losses. The battery is housed with the electrical controller in a package called the Intelligent Power Unit (IPU). The new packaging reduces the size of the system by 50 percent and allowed to place the IMA equipment behind the rear seat in the trunk. The unit weighs only 63 pounds and is one-third smaller than that of the Insight.

Honda Civic Hybrid

The Honda Civic Hybrid is a hybrid powertrain version of the Honda Civic, first introduced in Japan near the end of 2001. It comes with either a continuously variable automatic transmission or (until 2005) a 5-speed manual transmission. It uses an Integrated Motor Assist hybrid system similar to Honda Insight. The Civic Hybrid is only available as sedan, even in Europe until 2012, where it is replaced by its hatchback version.^{[citation needed]}
The Civic hybrid was introduced to the U.S. in spring 2002 as a 2003 model, based on the seventh generation Civic. As with the conventional Civic, it received a styling update for 2004. It is the first hybrid vehicle to be certified as an Advanced Technology Partial Zero- Emissions Vehicle (AT-PZEV) from California's Air Resources Board. The second generation Civic Hybrid is based on the eighth generation Civic, with some styling differences between the U.S. market and Japanese market models. The Civic hybrid ranks as the second best selling electric hybrid car in the U.S.^[1] As of the end of January 2009, the total global sales of all Civic hybrid exceeded 255,000.^[2]

Power-split or series-parallel hybrid

Typical passenger car installations include the Toyota Prius, the Ford Escape, the Lexus RX400h, RX450h, GS450h and LS600h.

In a power-split hybrid electric drive train there are two motors: an electric motor and an internal combustion engine. The power from these two motors can be shared to drive the wheels via a power splitter, which is a simple planetary gear set. The ratio can be from 0-100% for the combustion engine, or 0-100% for the electric motor, or an anything in between, such as 40% for the electric motor and 60% for the combustion engine. The electric motor can act as a generator charging the batteries.
On the open road, the primary power source is the internal combustion engine, when maximum power is required, for example to overtake, the electric motor is used to assist maximizing the available power for a short period, giving the effect of having a larger engine than actually installed. In most applications, the engine is switched off when the car is stationary reducing curbside emissions.

Fluid power hybrid

 Hydraulic and pneumatic hybrid vehicles use an engine to charge a pressure accumulator to drive the wheels via hydraulic or pneumatic (i.e. compressed air) drive units. The energy recovery rate is higher and therefore the system is more efficient than battery charged hybrids, demonstrating a 60% to 70% increase in energy economy in EPA testing.^[23] Under tests done by the EPA, a hydraulic hybrid Ford Expedition returned 32 miles per US gallon (7.4 L/100 km; 38 mpg_-imp) City, and 22 miles per US gallon (11 L/100 km; 26 mpg_-imp) highway.^[24] UPS currently has two trucks in service with this technology.^[25]

While the system has faster and more efficient charge/discharge cycling and is cheaper than gas-electric hybrids, the accumulator size dictates total energy storage capacity and requires more space than a battery.

Hybrid electric-petroleum vehicles

When the term hybrid vehicle is used, it most often refers to a Hybrid electric vehicle. These encompass such vehicles as the AHS2 (Chevrolet Tahoe, GMC Yukon, Chevrolet Silverado, Cadillac Escalade, and the Saturn Vue), Toyota Prius, Toyota Camry Hybrid, Ford Escape Hybrid, Toyota Highlander Hybrid, Honda Insight, Honda Civic Hybrid Lexus RX 400h and 450h and others. A petroleum-electric hybrid most commonly uses internal combustion engines (generally gasoline or Diesel engines, powered by a variety of fuels) and electric batteries to power the vehicle. There are many types of petroleum-electric hybrid drivetrains, from Full hybrid to Mild hybrid, which offer varying advantages and disadvantages.^[21]

Ferdinand Porsche in 1900 developed the first gasoline-electric series-hybrid automobile in the world, setting speed records using two motor-in-wheel-hub arrangements with a combustion generator set providing the electric power. While liquid fuel/electric hybrids date back to the late 19th century, the braking regenerative hybrid was invented by David Arthurs, an electrical engineer from Springdale, Arkansas in 1978–79. His home-converted Opel GT was reported to return as much as 75MPG with plans still sold to this original design, and the "Mother Earth News" modified version on their website.^[22]

The plug-in-electric-vehicle (PEV) is becoming more and more common. It has the range needed in locations where there are wide gaps with no services. The batteries can be plugged in to house (mains) electricity for charging, as well being charged while the engine is running.

Heavy vehicles

Hybrid power trains use diesel-electric or turbo-electric to power railway locomotives, buses, heavy goods vehicles, mobile hydraulic machinery, and ships. Typically some form of heat engine (usually diesel) drives an electric generator or hydraulic pump which powers one or more electric or hydraulic motors. There are advantages in distributing power through wires or pipes rather than mechanical elements especially when multiple drives—e.g. driven wheels or propellers—are required. There is power lost in the double conversion from typically diesel fuel to electricity to power an electric or hydraulic motor. With large vehicles the advantages often outweigh the disadvantages especially as the conversion losses typically decrease with size. With the exception of non nuclear submarines, presently there is no or relatively little secondary energy storage capacity on most heavy vehicles, e.g. auxiliary batteries and hydraulic accumulators—this is changing.

How often do hybrid batteries need replacing? Is replacement expensive and disposal an environmental problem?

The hybrid battery packs are designed to last for the lifetime of the vehicle, somewhere between 150,000 and 200,000 miles, probably a whole lot longer. The warranty covers the batteries for between eight and 10 years, depending on the carmaker and the location.

Battery toxicity is a concern, although today's hybrids use NiMH batteries, not the environmentally problematic rechargeable nickel cadmium. "Nickel metal hydride batteries are benign. They can be fully recycled," says Ron Cogan, editor of the Green Car Journal. Toyota and Honda say that they will recycle dead batteries and that disposal will pose no toxic hazards.
There's no definitive word on replacement costs because they are almost never replaced. We have seen anecdotal reports of total battery replacements costing about $3,000.

Can you tow with a hybrid?

 Towing a Toyota Prius or Honda requires front wheels off the ground. Honda’s (manual transmission) can be towed with wheels on the ground, but it’s not recommended. Honda’s with CVT can be towed with wheels off the ground. Tow dollies are commonly used.

Toyota and Honda will say not to tow anything behind their hybrids. Except for the Insight, which has an aluminum frame, it’s done everyday. Prius and Civic Hybrid can tow with a tongue weight of less than 100 lbs and total trailer under 1000 lbs. (Just basic guidance; be careful.)
General Motors Two-Mode Hybrids, like the Chevy Tahoe, are specifically designed for full towing capabilities. Other SUV hybrids have adequate towing power. For example, the Ford Escape Hybrid and Lexus RX 400h have towing capacities of 1,000 pounds and 3,500 pounds respectively.

Chevrolet Silverado

While some treehuggers put fuel economy above all other considerations, many trades people, commercial users, farmers and ranchers absolutely require the capabilities of a pickup truck. The Silverado Hybrid (and the similar Sierra Hybrid) are still the only gas-electric pick-ups on the market. For 2011, Chevrolet continues to offer the Silverado Hybrid in just one body style, a four-door crew cab with a short box. There are two trim levels, 1HY and 2HY, and a choice of either two- or four-wheel drive. The only change is an upgrade to GM’s OnStar 9.0 telematics system that the automaker says provides improved voice recognition.

Nissan Sentra

Nissan’s green PR is all about the electric LEAF, but at half the sticker price and 34 mpg on the highway, the Sentra deserves a look from the ultra-pragmatist. New Sentra models come with one engine, a 2.0-liter four cylinder, and two transmission options, a six-speed manual and a continuously variable transmission (CVT). The fuel-miser of the group is the CVT, and yes, today’s automatic transmissions often deliver better fuel economy than their manual cousins. With this combination, the Sentra achieves an EPA estimate of 27 city/34 highway and a combined 30 mpg. With the six-speed manual, the 2.0-liter engine dispenses 24 city/31 highway and 27 mpg combined.