Big leap for fusion: more energy produced than spent igniting fuel

Researchers in the US have overcome a key barrier to making nuclear fusion reactors a reality. In results published in Nature, scientists have shown that they can now produce more energy than put into igniting fuel, at least on an experimental scale. The use of fusion as a source of energy remains a long way off, but the latest development is an important step toward that goal.

Nuclear fusion is the process that powers the Sun and billions of other stars in the Universe. If mastered, it could provide an unlimited source of clean energy because the raw materials are plentiful and the operation produces no carbon emissions.

During the fusion process, smaller atoms fuse into larger ones, releasing huge amounts of energy. To achieve this on Earth, scientists have to create conditions similar to those at the center of the Sun, which involves creating very high pressures and temperatures.

There are two ways to achieve this: one uses lasers and is called inertial confinement fusion (ICF), another deploys magnets and is called magnetic confinement fusion (MCF). Omar Hurricane and colleagues at the Lawrence Livermore National Laboratory opted for ICF, with the help of 192 high-energy lasers at the National Ignition Facility in the US, which was designed specifically to boost fusion research.

A typical fusion reaction at the facility takes weeks of preparation. But the reaction is completed in an instant (150 picoseconds, to be precise, which is less than a billionth of a second). In that moment, at the core of the reaction, the pressure is 150 billion times atmospheric pressure. The density and temperature of the plasma created is nearly three times that at the center of the Sun.

The most critical part of the reaction, and one that had been a real concern for Hurricane’s team, is the shape of the fuel capsule. The capsule is made from a polymer and is about 2mm in diameter (about the size of a pinhead). On the inside it is coated with deuterium and tritium—isotopes of hydrogen—that are frozen to a solid state.

This capsule is placed inside a gold cylinder, when the 192 lasers are fired, they hit the capsule and indirectly cause a fusion reaction. The lasers hit the gold container, which emit X-rays that heat the pellet and make it implode, causing a fusion reaction. According to Debbie Callahan, a co-author of the study: “When the lasers are fired, the capsule is compressed 35 times. That is like compressing a basketball to the size of a pea.”

The compression produces immense pressure and temperature, leading to a fusion reaction. Problems with the process were overcome last September, when, for the first time, Hurricane was able to produce more energy output from a fusion reaction than the lasers put into it. Since then, he has been able to repeat the experiment.

Hurricane’s current output, although more than the hydrogen fuel put into the reaction, hasn’t yet reached the stated goal to achieve “ignition," where nuclear fusion generates as much energy as the lasers supply. At that point it might be possible to make a sustainable power plant based on the technology.

In plasma physics, the energy produced by a fusion reaction increases exponentially with the pressure applied to the system. According to Hurricane, they only need to double the pressure to achieve ignition. His other achievement is that, with these experiments, he has been able to show that computer simulations can predict experimental results.

Scientists have been trying to tame fusion power for more than 50 years with little success. Although the National Ignition Facility, a $3.5-billion operation, was built for classified government research, half of its laser time was devoted to fusion with an aim to accelerate research. Zulfikar Najmudin, a plasma physicist at Imperial College, said: “These results will come as a huge relief to scientists at NIF, who were very sure they could have achieved this a few years ago.”

With laser-mediated ICF showing positive results, the obvious question is how does it compare with magnet-mediated fusion? According to Stephen Cowley, director of Culham Centre for Fusion Energy, there isn’t a precise way of comparing the two technologies. But if a comparison has to be made, MCF still is ahead of ICF because a 1997 experiment by the European fusion leaders Joint European Torus achieved near break-even when they produced 16MW (megawatt) of energy for 24MW of input.

“We have waited 60 years to get close to controlled fusion. We are now close in both magnetic and inertial. The engineering milestone is when the whole plant produces more energy than it consumes,” Cowley said. That may happen at the fusion reactor ITER, under construction in France, which is expected to be the first power plant that produces more energy than it consumes to sustain a fusion reaction.

Nature, 2014. DOI: 10.1038/nature13008  (About DOIs).

This article was originally published on The Conversation.

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Artificial Hand by Bebionic significantly improves lives

Accidents happen and it is extremely difficult to predict its outcome. You may be either lucky enough to come out of it uunharmed, without even the smallest scratch or may suffer from grieve consequences. The stories of Charles Soitaboa Kango and Mike Swainger are very much similar. But with the help of BeBionic hand, they successfully live a normal life today and can do almost every activity without the slightest hitch.

Charles Soitabao Kango met with an accident while returning to his village. The accident crushed his hand severely and amputation was the only solution. That accident changed his life completely. Charles was just 15 training hours away from receiving commercial pilot’s license. But with the Bebionic hand, he can now resume his training and get his license again. Similarly, after an accident, Mike Swainger lost his hand. He was the first man in UK to receive the Bebionic hand which helped him overcome his loss. But, the artificial hand allows him to do all minor tasks which were previously impossible for him.

Bebionic hand is an advanced artificial hand that has a robot-like appearance. The hand allows the user to perform all types of tasks such as picking things, shaking hand with people, clicking a mouse, pushing a trolley or playing sports. The arm becomes a part of your body, without making you feel very different about it. It has been structured after a research of almost 20 years and hence, has taken into consideration of every single aspect that helps people live a normal life again.

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Is it time to move away from silicon-based solar?

CHICAGO—Currently, the world has the capacity to manufacture over 40 Gigawatts of solar panels each year, the vast majority of them silicon-based. And it's easy to see why: our expertise with processing the material has led to a staggering drop in costs, making photovoltaics (PVs) much more cost-competitive than just about anyone had predicted.

But that manufacturing innovation hasn't been matched on the basic research side; it's been over a decade since the last time anyone set a new efficiency record for silicon cells. And, even as manufacturing costs have dropped, the cost of support equipment and installation has remained stubbornly high and is an ever-increasing slice of the total price of PV systems.

That's got people thinking that it might be time that we get more power out of each installation. At the meeting of the American Association for the Advancement of Science, two researchers spelled out how they were finding ways to take an expensive material and make it cheap enough to be deployed on the same scale as silicon.

The material in question is gallium arsenide, which can be fashioned into solar cells with efficiencies twice those of silicon. The high cost of the material, however, has limited its use to applications like satellites. But two research groups have come up with ways to get much more out of GaAs.

Gallium goes thin

Both teams have figured out how to make extremely thin layers of GaAs. Harry Atwater's group at Caltech has developed a process that allows them to peel hundreds of thin layers off a large aggregate of the material, much like individual graphene sheets can be peeled off a block of graphite. The end result is an extremely thin film of GaAs (he passed some samples around to the audience).

John Rodgers, who works at the University of Illinois at Urbana-Champaign, grows thin layers of GaAs separated by a thin sacrificial layer. When the sacrificial layer is etched away, you're left with a collection of thin GaAs chips; the silicon wafer they were grown on can then be recycled, cutting down on the costs significantly. A plastic stamp can then pick up the chips and "print" them onto just about any surface, including one pre-patterned with wiring.

In the rare cases where GaAs chips are used here on Earth, they're typically used in what's called a concentrated solar system, where lenses pump as many photons into the chips as they can manage without melting. But these tracking and focusing systems add significantly to the cost of these systems. Both groups are thinking of doing some focusing, but going about it in different ways.

Rodgers, who can print large arrays of tiny GaAs chips, is managing costs by keeping things simple: his team's process simply involves dropping a plastic sphere that acts as a lens on top of the chip. There are some ideas about how to manufacture more specialized spheres that focus the light more efficiently, but, for now, simplicity is the selling point.

Trapping the photons

Caltech's Atwater is making the focusing device a more central part of his system for reasons that focused on the physics of what happens inside the chips. When a photon is absorbed, it creates a free electron and a positively charged "hole." There are three things that can happen to this pair. One is that they end up at electrodes, producing a useful current. One is that they recombine uselessly, releasing the energy as heat. The third is that they recombine by releasing another photon.

For Atwater, the key to an efficient photovoltaic material is minimizing the wasteful recombination of electrons and holes. And that means getting them to re-emit a photon—in his view, a good photovoltaic material is also a good LED. In these materials, photons get absorbed and re-emitted a hundred times before being productively harvested, and the inside of the material is a sea of photons.

The danger here is that some of the photons escape back out of the material. To limit that, the GaAs can be put on a reflective backing that sends the stray photons right back into the chip. The front has to let sunlight in, but then keep photons from escaping. To do that, he's testing a system that looks a bit like two U's with their bottoms fused (technically, it's back-to-back parabolic lenses connected by a narrow aperture). This takes photons from a broad area and funnels them into the PV chip. The other end of the U acts like a reflective cap, making it very hard for a photon to escape from the chip without being reflected back into it.

Grab all the wavelengths

At this point, we're pumping lots of photons into the GaAs device and keeping them there until they're absorbed. The next way to up the efficiency is to have multiple independent photovoltaic devices, each tuned to different wavelengths. Traditionally, this has been done with layered devices, where each layer takes out a specific chunk of the spectrum.

And that's what Rodgers' team is already doing, by placing a standard triple-junction cell (which absorbs three different chunks of the spectrum) on top of a fourth cell that grabs yet another chunk. Atwater hopes to use the optic devices his team is working on to split the light into colors and direct them to independent photovoltaic devices.

Both of these faculty members have started companies to try to commercialize their work, and the devices they're making are already above the 40-percent efficiency mark—double that of silicon cells. Rodgers' company already has a 5MW capacity plant, and he said that scaling up production to an 80MW capacity plant would let them produce devices that are cost-competitive with coal.

Lots of great sounding technologies never make it past the demonstration phase, or they get caught up in market forces beyond their developers' control. But in this case, market forces are clearly working in the devices' favor. As installation costs become an ever larger fraction of the total cost of a solar installation, it's clear that getting more out of each installation is likely to be critical.

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Carbon dioxide from exhaust can now be used to make new chemicals

Carbon capture is yet to become energy-efficient, but uses of CO₂ are growing.

To limit climate change, most governments focus on reducing the amount of carbon dioxide (CO₂) put into the atmosphere. But there are indications that such action won’t be enough—at some point, we will need to actively remove CO₂ from the air.

The removal of CO₂ is a big challenge, as it will require large amounts of renewable energy. For now, attention has focused on removing CO₂ from the exhaust of fossil fuel power plants, where it’s present in higher concentrations. Typically, that CO₂ is destined for carbon capture and storage (CCS), but another option is to skip the storage part—new research from Korea shows that it’s possible to take CO₂ directly from exhaust gases and make new chemicals.

Catch me if you can

CO₂ from an exhaust gas stream is often captured by nitrogen-containing compounds called amines. The reaction is reversible, as the products can be heated, allowing the CO₂ to be released. The gas can then be compressed, transported, and stored in geological features, such as depleted oil fields, or used as raw material in chemical factories.

Although trees and some microbes can capture CO₂ and incorporate it into more complex chemicals, humans have struggled to replicate the process on a large scale. Most chemical reactions involving CO₂ require expensive catalysts, high temperatures, or high pressures to make it react. The most common use of CO₂ as a chemical feedstock is in the formation of urea, which is found in around 90 percent of the world’s fertilisers.

In the new research, published in the journal Angewandte Chemie, Soon Hong and colleagues from the Institute for Basic Science in South Korea have caught CO₂ from exhaust gas and incorporated it into useful chemicals. One product is called alkynyl carboxylic acid, which has many uses, including making food additives. Another, cyclic carbonate, is used to make polymers for cars and electronics. Cyclic carbonates can also be used in place of phosgene, a very reactive and highly toxic chemical that is a starting material for a wide variety of useful products.

Hong compared these reactions to ones performed using highly pure CO₂, which is sold at a high price and requires lots of energy to make, in the same chemical reactions, but there was hardly any difference in the final yield.

As in CCS technologies, Hong passes exhaust fumes through a solution of amines, where CO₂ is captured and other gases pass unhindered. The resulting salt is then heated to yield pure CO₂ for chemical reactions. Hong can recycle the amine solution at least 55 times without a loss in yield.

Use me if you do

In another research paper just published in Nature Communications, Matthias Beller and colleagues at the University of Rostock in Germany show a new reaction that can use CO₂. Called alkene carbonylation, it usually requires the use of carbon monoxide (CO), which, as home detectors know well, is a highly toxic gas.

CO₂ has previously been used in the synthesis of carboxylic acids by using diethylzinc to drive the reaction. But diethylzinc is flammable in air. With the new reaction, Beller can make chemicals that are found in varnishes and paints with less risk of burning the lab down.

The researchers carried out a number of reactions and confirmed that the source of the newly formed C-O bonds was CO₂. This work shows that CO₂ can be used as a viable alternative to carbon monoxide in carbonylation reactions, which could increase the importance of CO₂ in the chemical industry.

While this is good news, energy is still needed to trap and use CO₂. But if researchers can increase the demand for CO₂ at industrial scale, they may also drive the development of some of the technologies needed for CCS.

Nature Communications, 2014. DOI: 10.1038/ncomms4091 and Angewandte Chemie, 2014. DOI: 10.1002/anie.201308341 (About DOIs).

This article was originally published on The Conversation

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A way to double the efficiency of solar cells is about to go mainstream

SUNLIGHT is free, but that is no reason to waste it. Yet even the best silicon solar cells—by far the most common sort—convert only a quarter of the light that falls on them. Silicon has the merit of being cheap: manufacturing improvements have brought its price to a point where it is snapping at the heels of fossil fuels. But many scientists would like to replace it with something fundamentally better.

John Rogers, of the University of Illinois, Urbana-Champaign, is one. The cells he has devised (and which are being made, packaged into panels and deployed in pilot projects by Semprius, a firm based in North Carolina) are indeed better. By themselves, he told this year’s meeting of the American Association for the Advancement of Science, they convert 42.5% of sunlight. Even when surrounded by the paraphernalia of a panel they manage 35%. Suitably tweaked, Dr Rogers reckons, their efficiency could rise to 50%. Their secret is that they are actually not one cell, but four, stacked one on top of another.

Dr Rogers gets round this by using a different material for each layer of the stack. He chooses his materials so that the bottom of the band gap of the top layer matches the top of the band gap of the one underneath, and so on down the stack. Each layer thus chops off part of the spectrum, converts it efficiently into electrical energy and passes the rest on.Solar cells are made of semiconductors, and every type of semiconductor has a property called a band gap that is different from that of other semiconductors. The band gap defines the longest wavelength of light a semiconductor can absorb (it is transparent to longer wavelengths). It also fixes the maximum amount of energy that can be captured from photons of shorter wavelength. The result is that long-wavelength photons are lost and short-wave ones incompletely utilised.

The problem is that the materials needed to make these semiconductors (including arsenic, gallium and indium) are costly. But Dr Rogers has devised a way to overcome this. Normal solar-cell modules are completely covered by semiconductor, but in his only 0.1% of the surface is so covered. The semiconducting stacks, each half a millimetre square, are scattered over that surface as a matrix of dots, meaning that a panel with an area of 125 square metres has half a million of them. Each stack then has a pair of cheap glass lenses mounted over it. These focus the sun’s light onto the stack, meaning that all incident light meets a semiconductor.

The semiconductor stacks themselves are printed onto a cell one layer at a time by a rubber stamp, which picks them up from a crystal wafer of the appropriate material. This wafer has been grown as a series of layers, separated by a substance which can easily be dissolved away. By scoring a chequerboard of cuts through the layers to create squares of the correct size, and then dissolving the filler, layer after layer of semiconductor squares are created, which the rubber stamp peels away and places on the cell. Repeat the process with the other three semiconductors, and package the whole thing with electrical connectors and a transparent protective coat, and—presto!—you have a highly efficient solar panel.

Semprius’s panels are now being tested at 14 sites around the world. How much they will cost to make when manufacturing is running at full tilt is not yet clear, but Dr Rogers said that Siemens, a big German firm which is one of Semprius’s investors, reckons that they have the potential to produce cheaper electricity than coal-fired generators can. Solar energy obviously cannot replace fossil fuels completely until the problem of banking some of what is collected during the day, for use at night, is solved. But at this sort of cost it can make a useful (and unsubsidised) contribution.

The new panels have aesthetic advantages, too. The 99.9% of them not covered by stacks can be used for art. Seen from the sun’s point of view (ie, straight ahead), they appear black because the lenses are focused on the stacks, which absorb all the light falling on them. Viewed obliquely, however, their foci are on other parts of the panel. The result, as the picture shows, can be quite pleasing—and certainly prettier than a coal-fired power station.

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Who needs sunlight? In Arizona, solar power never sleeps

GILA BEND, ARIZONA—Every afternoon during the summer, millions of people across the American Southwest come home from work and switch on their air conditioners, straining the power grid in states like Arizona. Traditional solar power—although perfectly suited to the sunny climes of this region—can’t meet this demand since the surge in use peaks just as the day’s sun is disappearing.

That’s why most power suppliers diversify, using electricity from different sources to meet local needs. Solar power is abundant in the middle of sunny, clear days, but energy from other sources—coal, nuclear, or hydroelectric power for example—is necessary at night or when the weather is bad.

But increasingly efficient technology is allowing solar plants to contribute for a longer period of time each day and produce energy even in cloudy conditions. The key is a design that allows them to store the sun’s energy to be used later. And new facilities, such as the Solana power plant that recently came online in Gila Bend, Arizona, are increasing solar energy’s niche by producing electricity several hours after the sun sets.

Decked out in a too-large hard hat, neon yellow vest, and some very trendy safety goggles, Ars recently had the opportunity to visit Solana and find out precisely how these plants power cities after dark.

A solar primer

Unlike traditional photovoltaic systems, which directly convert the sun’s energy to electricity by liberating electrons, these new plants use “concentrated solar power,” or CSP. As the name suggests, CSP relies on either mirrors or lenses to collect and focus the sun’s heat, which is then used to generate power.

CSP isn’t exactly novel. According to legend, Archimedes used giant hexagonal mirrors to create a “death ray” to set fire to Roman ships, saving the city of Syracuse from invasion more than 2,000 years ago (whether or not this scenario actually happened is hotly debated). In a more recent era, I remember watching my brother perform small-scale mass murder with a magnifying glass, concentrating the sun’s rays onto the delicate bodies of insects.

But in recent years, CSP technology has blossomed. Its first large-scale test was the Department of Energy-funded Solar One, built in California in 1982. Solar One was a “power tower” plant, in which mirrors are arranged in a circular pattern around a central tower. The mirrors concentrate and direct energy onto a receiver at the top of the tower, which heats synthetic oil inside. The hot fluid is then used to boil water in a traditional steam turbine.

A huge solar facility called Ivanpah recently went online in California’s Mojave Desert. It consists of three separate plants with massive power towers—each 46 stories tall—with a combined capacity of nearly 400 megawatts. It's currently the largest solar thermal facility in the world.

Today, CSP’s popularity is exploding. Nearly 1.3 gigawatts of CSP power came online in 2012 or will debut this year; that’s enough to power about a million homes (or one time-traveling DeLorean). Huge new plants are currently under construction in South Africa, Chile, China, Morocco, Israel, and elsewhere.

The major advantage of CSP is the potential for storage. Since the sun’s energy is already being converted to heat, it’s relatively straightforward to store some of this heat to create electricity later. A variety of storage media are used, including oil and beds of packed rock, but the most common is molten salt. These salts are highly effective at retaining thermal energy and can be heated to very high temperatures (over 1000 degrees Fahrenheit), making storage extremely efficient.

With thermal storage, these plants can either produce at maximum efficiency during the day or store some of the energy as heat to convert later when the sun isn’t shining. This adds not only flexibility to the power system—since the production curve can be tailored to match the demand curve—but also stability in case of cloudy or stormy conditions.

A field full of mirrors

The view from the top of Solana's cooling towers is impressive: row upon row of shiny mirrors stretch out in all directions, tilted toward the sun like thousands of soldiers standing at attention. It's clear from this vantage point that Solana is in a league of its own.

When this CSP plant went online in October of 2013, it became the largest working parabolic trough plant in the world (although Spanish parent company Abengoa is currently building an even bigger version in the Mojave Desert). Solana covers more than 1,900 acres in southern Arizona—that’s the equivalent of more than 1,400 football fields packed with mirrors and power equipment.

Abstractly, the concept behind a parabolic trough plant is the same as that in a power tower plant: concentrate the sun’s energy to heat fluid, which then boils water to create steam. However, the details differ pretty significantly.

In a parabolic trough plant like Solana, the mirrors are curved inward, with a glass tube running along the deepest point, or trough, of each mirror. The tube is full of synthetic oil (also known as heat transfer fluid, or HTF). The concave mirrors concentrate light onto this HTF, heating it to 740 degrees Fahrenheit. The system is extremely efficient in collecting heat and concentrating it to a blistering level; when I asked what would happen if I touched the tube, the reply was a curt "Trust me, you definitely don't want to do that."

Once the oil is up to temperature, about 270 miles of pipe transport it to the power block, where the HTF takes one of two pathways, depending on Solana’s current needs.

In the most direct route, the HTF is simply sent to the steam generator to boil water and create steam to drive two 140-megawatt turbines, just like a traditional power plant. This is the more efficient of the two pathways, since virtually no energy is lost between collection and conversion.

Huge overflow tanks allow for the expansion of the hot synthetic oil.

Alternatively, to store this energy for later production, the HTF can instead be sent to one of 12 giant salt tanks at Solana, where hot oil heats molten salt. Each tank can hold 12,000 tons of salt (the salt mixture used at Solana is 40 percent sodium nitrate and 60 percent potassium nitrate). The tanks function just like huge thermoses, holding the heat from the HTF for up to six hours. When electricity is needed, the hot salt is transferred into another holding tank, passing through a heat exchanger on the way. Cold HTF then passes through the heat exchanger in the opposite direction, picks up the heat, and travels to the steam generator in the power block to generate electricity.

Arizona Public Service, the state’s largest electric utility, has agreed to purchase all the power generated by Solana for 30 years. On a daily basis, APS determines how Solana should produce and store its energy in order to best meet local demand. Abengoa estimates that under optimal conditions, Solana can produce enough electricity to power 70,000 homes.

One traditional measure of a power plant’s utility is its capacity factor. A facility’s capacity factor is the ratio of the energy it produces over a certain amount of time compared to the potential energy the plant could produce if it could operate at full capacity the entire time. Plants converting renewable energy generally have low capacity factors because resources like wind and sunlight aren’t always available. But thanks to thermal storage, facilities like Solana have capacity factors of more than forty percent—that's twice as good as plants using photovoltaic technology.

In many ways, Solana’s system is highly automated. Each mirror assembly is outfitted with temperature and pressure sensors, as well as a hydraulic sun-tracking system to maximize the heat captured.

Maintaining this giant solar field, however, is complicated. The mirrors need to be kept virtually spotless, because the cleaner they are, the more quickly the HTF is heated to the optimal temperature. To keep all 3,200 mirrored collectors bright and shiny, the company has a fleet of trucks that spray and scrub each mirror either on a bi-weekly basis or as needed. Breakage is minimal, since the mirrors are tempered glass—just like car windshields—but Solana officials estimate that about one percent of mirrors require replacement each year.

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Technology of Hydrogen Fueled Rotary Engine | Dual Fuel System ( Hydrogen + Gasoline)

This hydrogen engine takes advantage of the characteristics of Mazda’s unique rotary engine and maintains a natural driving feeling unique to internal combustion engines. It also achieves excellent environmental performance with zero CO2 emissions. 
Further, the hydrogen engine ensures performance and reliability equal to that of a gasoline engine. Since the gasoline version requires only a few design changes to allow it to operate on hydrogen, hydrogen-fueled rotary engine vehicles can be realized at low cost. In addition, because the dual-fuel system allows the engine to run on both hydrogen and gasoline, it is highly convenient for long-distance journeys and trips to areas with no hydrogen fuel supply.

Technology of the RENESIS Hydrogen Rotary Engine:

The RENESIS hydrogen rotary engine employs direct injection, with electronically-controlled hydrogen gas injectors. This system draws in air from a side port and injects hydrogen directly into the intake chamber with an electronically-controlled hydrogen gas injector installed on the top of the rotor housing. The technology illustrated below takes full advantage of the benefits of the rotary engine in achieving hydrogen combustion.

RE Features suited to Hydrogen Combustion

In the practical application of hydrogen internal combustion engines, avoidance of so-called backfiring (premature ignition) is a major issue. Backfiring is ignition caused by the fuel coming in contact with hot engine parts during the intake process. In reciprocal engines, the intake, compression, combustion and exhaust processes take place in the same location—within the cylinders. As a result, the ignition plugs and exhaust valves reach a high temperature due to the heat of combustion and the intake process becomes prone to backfiring. 
In contrast, the RE structure has no intake and exhaust valves, and the low-temperature intake chamber and high-temperature combustion chamber are separated. This allows good combustion and helps avoid backfiring. 
Further, the RE encourages thorough mixing of hydrogen and air since the flow of the air-fuel mixture is stronger and the duration of the intake process is longer than in reciprocal engines.

Combined use of Direct Injection and Premixing

Aiming to achieve a high output in hydrogen fuel mode, a direct injection system is applied by installing an electronically-controlled hydrogen gas injector on the top of the rotor housing. Structurally, the RE has considerable freedom of injector layout, so it is well suited to direct injection. 
Further, a gas injector for premixing is installed on the intake pipe enabling the combined use of direct injection and premixing, depending on driving conditions. This produces optimal hydrogen combustion. 
When in the gasoline fuel mode, fuel is supplied from the same gasoline injector as in the standard gasoline engine.

Adoption of Lean Burn and EGR

Lean burn and exhaust gas recirculation (EGR) are adopted to reduce nitrogen oxide (NOx) emissions. NOx is primarily reduced by lean burn at low engine speeds, and by EGR and a three-way catalyst at high engine speeds. The three-way catalyst is the same as the system used with the standard gasoline engine. 
Optimal and appropriate use of lean burn and EGR satisfies both goals of high output and low emissions. The volume of NOx emissions is about 90 percent reduced from the 2005 reference level.

Dual Fuel System

When the system runs out of hydrogen fuel, it automatically switches to gasoline fuel. For increased convenience, the driver can also manually shift the fuel from hydrogen to gasoline at the touch of a button.

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Steering Systems | Hydraulic Power Steering Systems | Steering Wheel Parts

STEERING

The steering system in a vehicle is used to move the vehicle in a particular direction. This is a very important sub-system in a car without which it would be impossible for a vehicle to follow its desired path. The steering system can be used to steer all kinds of vehicles like cars, trucks, buses, trains, tanks etc.

The conventional steering system consisted of turning the front wheels in the desired direction. But now we have four wheel steering system mostly used in heavy vehicles, to reduce the turning radius, rear wheel steering system, differential steering system etc.

The basic components of any steering system are:-

                   1. Steering column

                   2. Steering box

                   3. Tie rods

                   4. Steering arms

The main geometry followed in steering is ACKERMANN STEERING GEOMETRY. It shows that while negotiating a curve, the inner wheel needs to follow a smaller path as compared to the outer wheel. This results in different steering angles for the respective tires.

STEERING RATIO is defined as the ratio of the turn of the steering wheel to the corresponding turn of the wheels, both which are measured in degrees. It plays an important role in determining the ease of steering. A higher ratio would mean that a large number of turns of the steering wheel is required to negotiate a small turn. A lower ratio would enable better handling. Sports cars usually have lower ratio while heavier vehicles have a higher steering ratio.

The Different types of steering systems are:-

                    1. Rack and pinion steering system

                    2. Recirculating Ball steering system

                    3. Power Steering

The Rack and Pinion steering system is the most common system found mostly in modern vehicles. It employs a simple mechanism. The parts of this system are steering column, pinion gear, rack gear, tie rods, kingpin. The circular motion of the steering wheel is transmitted to the pinion gear through the steering column and universal joint. The pinion is meshed with a rack which translates the circular motion into linear motion thus providing the necessary change in direction. It also provides a gear reduction, thus making it easier to turn the wheels. This system is preferred because of its compactness, efficiency, ease of operation. But at the same time it gets easily damaged on impact.

The Recirculation Ball steering system is employed in SUV’s and trucks. It uses a slightly different principle than the rack and pinion system. Here the motion is translated with the help of a recirculating ball gearbox, pitman arm and a track rod. It can transfer higher forces. But it is heavier and costlier than the rack and pinion system.

The Power steering system employs either one of the above systems and in addition has a hydraulic or electrical system connected to make it easier to steer. This helps in better control of the vehicle.

Other systems like steer-by-wire systems, drive-by-wire systems also exist, but they are not commercially used as of now but are most likely to replace the modern day steering systems in the future.

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