The governor is a device which is used to controlling the speed of an engine based on the load requirements. Basic governors sense speed and sometimes load of a prime mover and adjust the energy source to maintain the desired level. So it’s simply mentioned as a device giving automatic control (either pressure or temperature) or limitation of speed.
The governors are control mechanisms and they work on the principle of feedback control. Their basic function is to control the speed within limits when load on the prime mover changes. They have no control over the change in speed (flywheel determines change in speed i.e. speed control) within the cycle.
Take an example:
Assume a driver running a car in hill station, at that time engine load increases, and automatically vehicle speed decreases. Now the actual speed is less than desired speed. So driver increases the fuel to achieve the desired speed. So here, the driver is a governor for this system.
So governor is a system to minimise fluctuations within the mean speed which can occur as a result of load variation. The governor has no influence over cyclic speed fluctuations however it controls the mean speed over an extended period throughout that load on the engine might vary. When there’s modification in load, variation in speed additionally takes place then governor operates a regulatory control and adjusts the fuel provide to keep up the mean speed nearly constant. Therefore the governor mechanically regulates through linkages, the energy provided to the engines as demanded by variation of load, so the engine speed is maintained nearly constant.
Types of Governor:
The governor can be classified into the following types. These are given below,
1. Centrifugal governor
a) Pendulum type watt governor
Loaded type governor
i) Gravity controlled type
ii) Spring controlled type
2. Inertia and fly-wheel governor
3. Pickering Governor
Purpose of governor:
1. To automatically maintain the uniform speed of the engine within the specified limits, whenever there is a variation of the load.
2. To regulate the fuel supply to the engine as per load requirements.
3. To regulate the mean speed of the engines.
4. It works intermittently i.e., only there’s modification within the load
5. Mathematically, it can express as ΔN.
Terminology used in the governor:
1. Height of the governor (h):
Height of the governor is defined as the vertical distance between the centre of the governor ball and the point of the intersection between the upper arm on the axis of the spindle. The height of the governor is denoted by ‘h’.
2. Radius of rotation ®:
Radius of rotation is defined as the centre of the governor balls and the axis of rotation in the spindle. The radius of rotation is denoted by ‘r’.
3. Sleeve lift (X):
The sleeve lift of the governor is defined as the vertical distance travelled by the sleeve on spindle due to change in equilibrium in speed. The sleeve lift of the governor is denoted by ‘X’.
4. Equilibrium speed:
The equilibrium speed means, the sped at which the governor balls, arms, sleeve, etc, are in complete equilibrium and there is no upward or downward movement of the sleeve on the spindle, is called as equilibrium speed.
5. Mean Equilibrium speed:
The mean equilibrium speed is defined as the speed at the mean position of the balls or the sleeve is called as mean equilibrium speed.
6. Maximum speed:
The Maximum speed is nothing but the speeds at the maximum radius of rotation of the balls without tending to move either way is called as maximum speed.
7. Minimum speed:
The Minimum speed is nothing but the speeds at the minimum radius of rotation of the balls without tending to move either way is called as minimum speed.
8. Governor effort:
The mean force working on the sleeve for a given change of speed is termed as the governor effort.
9. Power of the governor:
The power of the governor is state that the product of mean effort and lift of the sleeve is called as power of the governor.
10. Controlling force:
The controlling force is nothing but an equal and opposite force to the centrifugal force, acting radially (i.e., centripetal force) is termed as controlling force of a governor. In other words, the force acting radially upon the rotating balls to counteract its centrifugal force is called the controlling force.
India is building world's highest railway bridge.
Indian engineers are toiling in the Himalayas to build the world's highest railway bridge which is expected to be 35 metres taller than the Eiffel Tower when completed by 2016.
The arch-shaped steel structure is being constructed over the Chenab River to link sections of the spectacular mountainous region of India's northern Jammu and Kashmir state.
The bridge is expected to be 359 metres (1,177 feet) high when completed -- surpassing the world's current tallest railway bridge over the Beipanjiang River in China's Guizhou province, which stands at 275 metres high.
"It is an engineering marvel. We hope to get this bridge ready by December 2016," a senior Indian Railways official told AFP.
"The design would ensure that it withstands seismic activities and high wind speeds," he said Wednesday.
Work on the bridge started in 2002 but safety and feasibility concerns, including the area's strong winds, saw the project halted in 2008 before being green-lighted again two years later.
The estimated cost of the project, which is being handled by Konkan Railway Corporation, a subsidiary of state-owned Indian Railways, is $92 million.
The bridge will connect Baramulla to Jammu in the Himalayan state with a travel time of six-and-a-half hours, almost half the time it currently takes.
The main arch is being erected using two cable cranes attached on either side of the river which are secured on enormous steel pylons, according to engineers of the project.
The 1,315-metre long bridge will use up to 25,000 tonnes of steel with some material being transported by helicopters due to the tough terrain, they said. "One of the biggest challenges involved was constructing the bridge without obstructing the flow of the river," the railways official said. "Approach roads had to be constructed to reach the foundations of the bridge," he added.
Source: Zee News
During the years of extensive asbestos use in industry, mechanical engineers were at risk of exposure to asbestos under the widest variety of conditions and circumstances.Mechanical engineering is the design, analysis, testing, and production of products. Mechanical engineers traditionally worked in chemical, aerospace, and automotive industries among others, and are now working in bioengineering and environmental fields in addition to the traditional mechanical engineering fields. Among other things, mechanical engineering involves work in electrical circuitry, thermodynamics and heat transfer.These areas of work brought mechanical engineers into contact with vast amounts of asbestos during the height of asbestos use
Between 1940 and the late 1970s,asbestos was used in over 3000 different products. Asbestos is still used for some products, primarily brake pad linings and gaskets, in the United States, and there is asbestos in older products that people come in contact with meaning the risk of exposure still exists. Asbestos has some unique properties that made it a valuable resource for hundreds of years. Asbestos is chemically inert, entirely fireproof, and insulates extremely well against both heat and electricity Unfortunately, asbestos which is ingested or inhaled is highly carcinogenic
Risks at Work
People generally realize that most jobs present a chance for work-related injuries. Still, in America today, we expect that job-related dangers will be kept to a minimum, risks
will be clearly understood, and companies will attempt to create a safe work environment. Until relatively recently, however, in terms of asbestos exposure, workers often toiled without respirators or other safety gear in spaces where asbestos dust clouded the atmosphere.
The Varieties of Asbestos and Their Health Effects
There are two major categories of asbestos. The most commonly utilized was "white" asbestos, or the serpentine type. This is a relatively pliable form that is usually not linked to mesothelioma or asbestos cancer. Abrasions on the interior surfaces of the lungs can happen if serpentine particles are inhaled, however. This then causes a build-up of scar tissue that can then be a major factor in the development of asbestosis.
The second type is called amphibole asbestos and is much more deadly. A rare, but generally fatal, disease caused by asbestos called mesothelioma is caused by inhaling asbestos, particularly the amphibole varieties. The pleural variety of mesothelioma, one that affects the tissue that lies between the lungs and the chest cavity, is the most prevalent. More unusual types of mesothelioma include pericardial and peritoneal mesothelioma; these cancers are also caused by exposure to amphibole asbestos.
Hidden Hazard of Asbestos
As opposed to typical workplace injuries, which are readily observed and known about soon after the incident, asbestos-related diseases can take ten, twenty, or even thirty years to appear. With such a lag between exposure to asbestos and the appearance of the resulting disease, the worker might not connect his or her current health problem with work done 10 or more years ago. New treatments like mesothelioma radiation are being discovered, and early detection gives patients the highest chance to combat the previously always-fatal form of cancer. Such advancements can help better the usually grim mesothelioma survival rate. So, it is vital for men and women that worked as mechanical engineers, as well as anyone who spent much time with them, to notify their physicians about the chance of asbestos exposure.
Superchargers are automotive performance products that may be factory-installed or added as an aftermarket upgrade. The job of a supercharger is to increase engine power and performance by a process known as forced-air induction. This simply means increasing the amount of air flowing into an engine's combustion chambers via the intake manifold. This increase in the amount of air allows for a relative increase in fuel that may be added to the combustion mixture, translating into a bigger bang that produces more horsepower.
How A Supercharger Does Its Job
A basic, four-stroke internal combustion engine completes four processes per cycle, the first being the intake stroke. During this stroke, air and fuel are drawn into the combustion chamber, where the mixture is then compressed and ignited by the spark plug. The correct ratio of air-to-fuel for optimum efficiency is 14:1.
The size of the explosion during the combustion stroke is what determines engine horsepower. One way that engine horsepower can be slightly increased is by enlarging cylinder size, thereby increasing the capacity of the combustion chamber, allowing for a larger volume of air and fuel (still in the 14:1 ratio) to be ignited. To get a greater increase in horsepower without reverting to cylinder boring, one can simply add a supercharger.
Normally, air drawn into the combustion chamber is at atmospheric pressure, which, at sea level, is 14.7 psi. A supercharger compresses this air, typically to between six and nine more psi, before sending it to the intake manifold. With this 50 percent increase in pressure, 50 percent more air can be introduced into the combustion chamber, requiring a 50 percent increase in fuel, keeping the 14:1 air/fuel ratio in tact. With more fuel being combusted, more horsepower is produced.
Types of Superchargers
There are two basic types of , distinguished by the method each employs to compress air.
Positive Displacement – delivers a near constant level of pressure and air volume at any speed. First designed and patented in 1860 by the Roots brothers, Philander and Francis, of Connersville, Indiana, their "air mover" was first used in blast furnaces and mine shafts. The first supercharged production cars, using the Roots supercharger, were two 1921 Mercedes, models 6/25/40 and 10/40/65. These cars were designated "Kompressor" models, a designation that still lives on today to signify Mercedes-Benz automobiles with factory-installed superchargers. Other types of positive displacement superchargers include the twin-screw type and the sliding vane type.
Dynamic compressors – deliver increased air pressure as engine speed increases. More efficient than positive displacement models, they accelerate incoming air to high speed then diffuse that speed to produce high pressure. Examples of this type are centrifugal, pressure wave and axial flow. Centrifugal are the most common and most efficient of air-induction systems. These performance products are fairly easy to install and several manufacturers offer bolt-on kits that allow car owners to supercharge their rides quickly and easily. Some manufacturers of these performance products include: Keene Bell, Vortech, Saleen, ProCharger, MagnaCharger and Whipple.
Efficiency Equals Economy
It might seem that adding a supercharger to a vehicle would decrease its fuel efficiency, since more air requires more fuel to burn. In regular engines, however, some of the fuel remains unburned and ends up wasted, going out in the exhaust. Additional air supplied through a supercharger system makes for more complete combustion, which is more efficient. In addition, smaller, lighter engines can be used to generate greater power. This produces a lighter-weight vehicle, which will bolster efficiency. Putting the pedal to the metal, however, will quickly negate any fuel savings that might have otherwise been gained.
There has always been a debate and discussion among all engineering students about which engineering course is the best? Students always love discussing about the best branch of engineering. Though this is a proven fact and it needs no discussion that mechanical engineering is the best still I will be providing 10 reasons over here which make mechanical engineering The Best among all other branches of engineering.
#1 Evergreen Field: Mechanical engineering is an evergreen field. Applications of mechanical engineering have spread over such a wide spectrum that it has penetrated into almost every industry. Mechanical engineering got its application started right from the birth of this universe and it will continue till the end of this universe.
#2 Mother Of All Engineering Disciplines: Yeah it’s mother of all engineering disciplines and you know it! Mechanical engineering links all engineering disciplines together and provides a base for all engineering education.
#3 Everything Is Mechanical: Mechanical engineering has its application in all fields of life. May it be medicine, construction, automobile or even software and IT industry. Everything you see around you involves mechanical engineering to some extent.
#4 Everlasting Scope: Scope of mechanical engineering is everlasting. Mechanical engineering graduates can find career placements in almost every sector, right from construction sector to steel industry and from automobile to software.
#5 Best Job Offers: Mechanical engineers get best job offers after graduation. It’s one of the highest paid jobs all over the world.
#6 Social Status: Mechanical engineers are respected in every society. They possess a respectful social status among masses. They are like global ambassadors. Wherever they go, they are treated with respect.
#7 Most Interesting: Mechanical engineering involves study of some of the most interesting phenomena of science and engineering. The basic focus during study is on subjects such as thermal engineering, fluid sciences, machine design, industrial engineering and production engineering.
#8 Even GOD Loves ME: Ever thought GOD also implemented mechanical engineering in nature? Motion of your body, arms, hands and feet involves mechanical engineering. Your heart pumps blood and it runs through all your veins. This is again application of mechanical engineering. The more you look into nature with the eye of a mechanical engineer, you will find more application of it.
#9 Best Lifestyle: Do you need a best lifestyle to live in? Mechanical engineering offers you one of the best lifestyles. It’s like a dream come true.
#10 Vast Industry: Mechanical engineering industry is vast. Every industry needs mechanical engineers to run its business smoothly.
Do you have more reasons to say? Don’t forget to comment. Let us see how many reasons we can gather here in comments. I hope you enjoyed reading 10 reasons why mechanical engineering is the best course. No doubt It's best engineering course and best engineering branch!
Introducing undergrads to CFD and FEA software isn't a straightforward affair.
mechanical engineering students have a lot to learn and only a few short years to do it. First, they'll need to be versed in engineering concepts and the mathematics behind them. Then, they'll have to learn a slew of mathematical formulas and to become proficient in computer-aided design software.
With this pressing schedule, it's easy to see why engineering schools are scrambling to define the role that analysis software should play in their undergraduate programs. The software is relatively new to nonspecialists, and many mechanical engineers now use analysis software on the job.
Professors want their students to get up to speed on the technology, but they question at what stage they should introduce the software, according to Milos Coric, manager of the manufacturing and process laboratories at Northwestern University in Evanston, Ill.
Instructors are also questioning how to ensure that students understand what they are asking of the software, Coric said. They also wonder how to fit the subject of computer-assisted engineering into an already-packed undergraduate schedule. And which package should they use for instruction, anyway?
Today's engineering students need to know how to use analysis software. But when and how do professors introduce them to it? That is the question.
After all, analysis software made the everyday engineering scene only fairly recently. From its inception in the 1940s until about a decade and a half ago, finite element analysis had been performed exclusively by specialized analysts who held Ph.D.s in the subject and had devoted their careers to the discipline. But the FEA field has seen great change over the past 15 years, with a jump in the number of computer technologies available to an increasing number of engineers.
Computerized fluid dynamics has become mainstream more recently, but many engineers are finding it just as important to their daily work.
In order to prepare engineers to enter such a world, professors have begun a conversation to determine the best way and the best time to introduce students to the analysis software they'll likely need on the job. The subject is more challenging, both to learn and to introduce into the curriculum, than computer-aided design.
"CAD and CAE complement each other and are critical for building and testing products virtually, but this stuff is changing all the time," said Krishnan Suresh, an assistant professor of mechanical engineering at the University of Wisconsin in Madison. "So how do you address this adequately in the college setting where students not only need to learn what it is, but how to do it? And what package do you use?"
Universities also question the breadth and depth with which they should introduce students to CFD and FEA practice. Many of these students, after all, will not go on to study fluid flow and FEA at a graduate level. And they'll likely receive on-the-job training in the applications they'll use at work, although they'll certainly need to understand analysis concepts, said Dave Anderson, a professor of mechanical engineering and computer sciences at Purdue University in West Lafayette, Ind.
First Comes CAD
Instructors agree that their students first need a good grounding in CAD before moving on to analysis. Coric said that, at Northwestern, introduction to the software comes after instructors are sure students are comfortable with CAD and have become familiar with a range of analysis concepts.
According to Suresh, teaching CAD is a lot easier than teaching CAE, so schools are finding they can't substitute their CAD teaching methods when it comes to CFD and FEA.
"CAD focuses on geometry and most of us have a natural ability to visualize geometry," Suresh said. "I know what you mean by a cube or a sphere. I can visualize what you're talking about. Also, CAD relies on concepts like geometry confirmation and intersections. They're not trivial, but they're easier to understand because I can draw on a board to say, 'Here's what I mean by intersection.'
"But CAE relates to complex physical phenomena like fluids and things breaking and corroding," he added. "They're more difficult to teach and students can't visualize much of this easily."
Analysis concepts can be tricky to wrestle with and the introduction of software into the mix can become a bit of a chicken-and-egg scenario, Anderson said. It can be difficult for students to visualize the analysis problem they're asking the software to solve. CAE can help them visualize such problems, but without proper background in analysis concepts they won't understand what they're looking at.
According to Suresh, "These are the difficulties you face in teaching CAE. We want to teach CAE at a level that's ready for industry, but our main challenge is time. Every department in the country is facing a challenge because we don't have space in our curriculum. Students are increasingly pressured by parents and funding issues to get out in four years and be ready for industry."
Northwestern University recently introduced Fluent CFD software from Ansys Inc. into its classrooms. The company is a participant in Partners for the Advancement of Collaborative Engineering.
Each school finds its own way to introduce concepts like fluid flow and FEA, and then the software behind it. Purdue University, for example, now offers senior-year elective classes that focus on computer-aided engineering, but every undergrad will receive CAE training, Anderson said.
"I don't believe I know the answer to, 'How do you teach CAE?' " he said. "It's still a learning process for all of us, but based on my experience you introduce the basics of heat transfer or fluid flow at a point in the curriculum. Then, you introduce CAE methods directly into those courses. Students can solve simple textbook problems using Ansys or Nastran."
Northwestern recently incorporated Fluent CFD software from Ansys Inc. of Canonsburg, Pa., into its classrooms. The software is part of the Partners for the Advancement of Collaborative Engineering, or PACE, program, which sells discounted software to universities. It's a joint venture of General Motors, Sun Microsystems, and Siemens PLM Software, and their partners and supporters, such as Ansys.
According to Coric, "Basically, before Fluent ours was a theoretical approach, with not much CFD software at all."
Getting a proper grounding in the principles of fluid flow and the like before firing up a software program helps students better understand the basics of engineering, Suresh said. Half the battle is ensuring that students can accurately frame and input the problems they want CFD and FEA to analyze, he added.
Identifying the problem in a simple manner is one of the most important lessons CAE teaches, Suresh said. "Despite advances in software programs, many complex problems can't be solved with them," he said. "Students need to be trained to say, 'How do I simplify the problem?' That's the core of engineering.
"There's no way to capture the detail of a full engineering automotive model, after all, so students need to learn to ask themselves: 'Is the problem linear? Nonlinear? What forces need to be analyzed?' " Suresh added. "Students soon realize CAE is about asking the right questions. That's why we need to teach CAE. That's the core of engineering, and software can help teach it.
"CAE is not about clicking a few buttons and solving a problem. It's about giving them an auto structure chassis and saying, 'Give me what the vibration of the chassis is,' " he said. "If they can do it, they know CAE. If not, they've learned to move some buttons around."
Nothing Is Perfect
The professors interviewed for this article all agreed upon the need for students to crosscheck the results that their software programs return. Software may seem miraculous at first blush, but is, after all, only as good as its programming and as the engineering information supplied.
Fledgling engineers must learn FEA and CFD concepts before they can understand the results the software returns, Suresh said. They can't just rely on software as a tool to spit out the answer. In fact, students need to know that the software can make mistakes. And they have to be primed to find those mistakes.
"Students really need to be trained to ask, 'How can I be sure the colorful plots reflect reality?' " he said.
Anderson at Purdue emphasizes to his students that analysis is more than a colorful picture. Nor can they operate a program by simply plugging in numbers, waiting a bit, then getting correct results.
<b>Fledgling engineers need to learn FEA and CFD concepts before they can understand the results the software returns. In fact, students need to know that the software can make mistakes. </b>
"We try to connect software to theory, to ask them to do a sanity check on the numbers. Don't trust the numbers," he said. His students analyze two-dimensional projects they've designed in Pro/Engineer, using both Pro/Mechanica from PTC of Needham, Mass., and Ansys. Students use 2-D to see results more readily without getting bogged down in pictorial simulations, Anderson said. The Purdue program also deliberately mixes Ansys and Pro/Mechanica to expose students to different analysis programs.
Educators said that, to double- and triple-check the results that software returns, students will have to repeat analyses again and again. They should solve the problems in more detail to see if the results remain stable. If results fluctuate, the results are suspect.
Results must stay the same as students solve with finer and finer detail, Suresh said. Students can also cross-check the software's solution by making a change to the model to see if results change as expected.
That point cuts to the crux of the problem, as Coric sees it: How do professors best give students a CAE problem they can solve? Textbook problems are very easy to solve, but don't have the challenges of the real world.
Coric often has students use Fluent to verify problems they've solved by hand.
Suresh warns that the transition from simple textbook problems to real-world problems won't be easy for students. After all, engineers use CAE on the job to solve complex problems.
To help students take small steps into real-life applications while still in college, Northwestern encourages them to compete in design-build competitions like the North American Solar Challenge and the Formula Sun Grand Prix.
"To be competitive, all these teams have started using software to analyze suspension and kinematics and airflow around their vehicles," Coric said. "They're running a whole project from scratch, from design to analysis, to hopefully race and hopefully win."
Along with figuring out how to introduce CAE and when to introduce it during the undergraduate years, schools consider what package to use. Each one will likely choose something that meets the needs of industries that frequently recruit its graduates, and that meshes with teaching style and method.
The CAE package a school eventually goes with should be well integrated with its primary CAD system, Suresh said. Not only does it make quick analysis easier, because a student can click over to the analysis program directly from the CAD application, but it saves faculty members from teaching two separate software environments, he said. He added that CAE packages that include well-integrated pre- and post-processors save schools the need to buy those applications separately.
The application should also be able to handle real-world geometry.
"I want students to solve real-world problems," Suresh said. "Many CAD systems are limited to simple 2-D. That is a stumbling block." He wants to see students informed about 2-D and 3-D analyses.
Schools must consider the packages most often used by the companies for which their students will likely work. But instructors shouldn't be unduly swayed by that consideration, he said.
"Each industry has its own favorites, but you're training them more like a technician when you just train them on one particular software," Suresh said.
As with many things in this age of advanced engineering technology, undergraduate institutions are finding their way toward using CFD and FEA software in the classroom. The learning process continues for everyone.
Many of us may know about two stroke or four stroke engine.Those who are from mechanical or automobile field must have to familiar with this term.Actually two stroke or four stroke is the cycle of any reciprocating engine.When only two stroke required to complete the reciprocating engine cycle then that engine is known as two stroke engine,and when four stroke required to complete the cycle then it is known as four stroke engine.
In four stroke engine the work is obtained only during one stroke out of these for a single cylinder engine or for every cylinder individually for multicylinder engine.If you have any automobile vehicle or machine,then you better know the above terms.But ever you know,which are these strokes and how it perform? Interested to go deep in topic? Read below description.
This is first stroke of your engine.During this stroke the piston is moved downward from Top Dead Centre by means of crankshaft which is rotate by electric motor.This movement increases the size of combustion space thereby reducing the pressure inside the cylinder,as the result,the higher pressure of the outside atmosphere forces the air into combustion space through suction valve.The exhaust valve remain closed in this stroke.
A carburettor is put in the passage of incoming air which supplies a controlled quantity of fuel to this air.This air-fuel mixture thus comes in engine cylinder.
This is second stroke of your engine.The air-fuel mixture is compressed during this upward stroke.The compression,forces the fuel into closer combination with air.Heat is produced due to compression aids the combustion of fuel.Just a little before the end of compression stroke the mixture is ignited by a spark produced by spark plug.During this stroke suction and exhaust valve remain closed.
This is third stroke of your engine.You may call it as Expansion Stroke also.The air-fuel mixture which burns at the end of compression stroke expands due to heat of combustion.This expansion of burnt air-fuel mixture exerts pressure in the cylinder and on the piston,and under this impulse the piston moves downward thus doing useful work.Suction and exhaust valve remain closed during this stroke.
This is last stroke of your engine.During this stroke the suction valve remain closed while the exhaust valve opens.The greater part of burnt gases escape because of their own expansion.The upward movement of piston pushes the remaining gases out of the open exhaust valve.Thus complete the exhaust stroke and one cycle of engine.
Number of cycles are depend upon the rotation per minute of your engine.Higher the R.P.M.,higher the workdone carried out by engine.I hope,this information will better help you to understand the working of your four stroke engine.
Before cars and buses can make their mark, some developers say the best economic case for fuel cell mobility applications may be found in the warehouse
At a gathering of fuel cell developers at Germany's giant Hanover Fair this past April, Jacob Hansen talked about plans of his Danish startup, H2 Logic A/S, to launch the first of seven fuel cell-powered demonstration cars in Scandinavia this fall.
Not possible, countered someone else close to the project, looking at a mockup of the vehicle across an aisle. Too much engineering remains, he said.
No, replied another member of the H2 Logic team, the car will be ready.
Fuel cells promise mass transit without the pollution, odor, or noise. While several cities operate prototype fuel cell buses, their range is limited and their costs aren't competitive with conventional engines.
In popular perception, the automobile has become the poster child of the fuel cell revolution, but the exchange at Hanover underscores the rocky road to commercialization. Until there are service stations where a driver can pull in and buy hydrogen, the personal automobile is irrelevant. Municipal buses avoid that problem. They circulate within driving distance of a central fueling station. It could contain hydrogen as well as any other fuel.
But there is another vehicle that is drawing attention for its possibilities in the fuel cell universe. It doesn't even go onto the public highway, so it stays close to its fuel supply. It isn't a toy, and in fact does essential work, and it is around these points that developers are trying to build a business case for it. According to several developers, the road to fuel cell buses and cars will be traveled first by the lowly forklift.
Why forklifts? Fuel cell vehicles may dazzle with the claim of zero-emission performance, but somehow the wedding of technology and practical uses keeps getting pushed back. More than 30 years after fuel cells were touted as a solution to the original energy crisis, the global industry's research and development spending is still twice as high as its total sales, according to a survey by the U.S. Fuel Cell Council.
Engineers have solved many of the issues that made real-world uses a receding target.
Equally important, politicians responding to high oil prices and increasing concern over global warming have begun to pump money into alternative fuels. This past March, for example, Germany proclaimed that it would invest 500 million euros over the next 10 years and subsidize half the purchase cost of any fuel cell vehicle. The U.S. Department of Energy is ramping up spending, and the Federal Transit Administration recently set aside $49 million to test fuel cell buses.
No wonder H2 Logic was at April's Hanover Fair with 130 other fuel cell exhibitors, 30 percent more than turned out in 2006. February's Fuel Cell Expo in Tokyo drew 462 exhibitors, up 50 percent from 2006, and 24,494 visitors from 53 countries.
They are following the money, hoping that government funding will help close the cost gap between today's fuel cells and tomorrow's commercial vehicles. Yet even if the government picks up half the tab, it's not easy to find applications that make economic sense.
Although fuel cell cars get lots of press—and nearly every major automaker and many smaller companies like H2 Logic have small fleets—they are essentially prototypes.
Buses are more promising. "There is a real market in fuel cells for buses," said one exhibitor at Hanover. Yet fleets remain small. Europe's largest demonstration program involves 11 cities, if you include Perth, Australia, and about 27 buses. Berlin hopes to use German subsidies to launch a fleet of 14 buses.
More typical is Sunline Transit Agency of Thousand Palms, Calif. It operates two hydrogen-powered vehicles, but only one uses a fuel cell. The other burns hydrogen in an internal combustion engine. In November 2006, Sunline received a $2.8 million grant to put a second fuel cell bus into operation in 2008.
In the arguments of developers, economics set fuel cell forklifts apart from other vehicles. One of those arguments is offered by Mark Kammerer, head of business development for Hydrogenics Corp., a Mississauga, Ontario, developer of fuel cells that is partly owned by General Motors Corp.
According to Kammerer, a large warehouse might operate a fleet of 200 or 300 forklifts. Each forklift battery operates for eight hours on a single charge. Most 24/7 warehouses need more than one battery for each forklift. While one powers the machine, the other recharges, and perhaps a third is kept as a backup. When the forklifts run low, they go back to the recharging station to swap out batteries.
This is no simple operation. A very large forklift battery can weigh as much as 1.5 metric tons. A Nascar pit stop crew might be able to trade large batteries in as few as 10 minutes, but Kammerer estimates that 15 or 20 minutes is more common.
Now imagine doing that for a fleet of 200 vehicles. If a crew can average four battery swaps per hour, it can do 32 swaps per day. It would take six or seven stations to service all 200 vehicles in a single shift, and 9 or 10 stations for a fleet of 300 vehicles. Companies must also pay for the costly disposal of hazardous spent lead-acid batteries.
In addition to labor costs, Kammerer points to a cost in space. Most warehouses are searching desperately for more room. Many have raised their storage racks higher and higher, seeking every bit of available space. Most would be all too happy to reclaim the space now taken up by battery storage and swapping stations.
Purolator Courier Ltd. has tested electric hybrid and fuel cell delivery vehicles. The vehicles combined hydrogen-based power plants with a battery to provide acceleration power.
Purolator Courier Ltd. has tested electric hybrid and fuel cell delivery vehicles. The vehicles combined hydrogen-based power plants with a battery to provide acceleration power.
Fuel cells address both issues, Kammerer said. Warehouse and factory managers can install a small hydrogen plant outside the building, a practice common among industrial gas users. Inside, fueling stations take up only a fraction of the room now housing batteries and service bays. Warehouses can reclaim that area.
Refueling takes less than two minutes, and forklift operators can do it themselves, according to Benedikt Eska, CEO of Proton Motor Fuel Cell GmbH of Starnberg, Germany. This eliminates the need for dedicated "pit stop" teams to swap out batteries. Fuel cells also run about 12 hours between refueling, so fleets refuel two times per day instead of three.
"We think we need to show the total cost of ownership before we can compete economically with battery-powered fuel cells," Eska said. That means not only initial costs, operating costs, and product life, but also maintenance costs and up-time reliability. "We think we need to show fuel cell lifespans of 5,000 hours to compete with a forklift with a one-battery set and 10,000 hours with a forklift with a two-battery set." Until he has more field experience with long-term service costs, it's hard to mount a believable economic argument.
Fuel cells also pose a more easily solved problem. Although they take up as much space as lead-acid batteries, they weigh much less. The cell packs are so light that a truck can tip over when lifting heavy loads. Of course, the problem is easily solved by adding some lead or other weights under the fuel cell system.
Several companies have already invested in small fuel cell forklift fleets. Hydrogenics, for example, is planning a two-year test of 19 fuel cell forklifts at General Motors in Oshawa, Ontario. Proton Motor, Nuvera Fuel Cells (a Cambridge, Mass., supplier owned by Hess Corp., Renault S.A., and Gruppo De Nora), and General Hydrogen (Canada) Corp. in Richmond, British Columbia, have smaller tests or development alliances under way.
Fuel cells remain a work in progress, however. They have yet to reach the 5,000-to-10,000-hour lifespan Eska estimates they need to compete with batteries. Thanks to materials, designs, and filters, both Eska and Kammerer expect cells to last about 3,000 hours in a forklift. That is equivalent to one-third of a year in a facility running 24/7. Both men say their companies have bench-tested fuel cells that last 5,000 to 8,000 hours, but Eska warns that those results are for cells, not complete systems.
Nickels and Dimes
Catalysts are another sore point. They are made of platinum, a metal associated with jewelry when gold is just not expensive enough. No matter how thin a coating developers use, platinum is a major cost. Developers try to circumvent the problem by recovering platinum from spent fuel cells. Hydrogenics, for example, recovers about 98 percent of its catalyst, Kammerer said. Yet recovery remains costly. Those 2 percent losses also add up: A fleet of 20 forklifts running 24/7 would lose the equivalent of 1.2 fuel cells' worth of platinum every year.
Critics note that there isn't enough platinum in the ground to serve potential fuel cell markets.
Several companies are investigating other catalysts, most notably nickel-based nanoparticles. Although nickel has lower catalytic activity than platinum, nanoparticles have a much higher surface area per unit volume than conventional platinum coatings. Researchers hope the sheer number of catalytic sites on nanoparticles will enable them to achieve the same amount of activity as an equivalent area of platinum.
The key to using nanoparticles is finding a way to make all that surface area available. Several companies are attacking the problem. In Crespina, Italy, for example, Acta S.p.A. bonds nickel and other metal nanoparticles to polymers, which it then coats onto cheap and highly porous carbon black. Heating the carbon black vaporizes the coating, leaving nickel nanoparticles applied evenly over all the pores.
"The key is the size of the particles and how you deposit them," said Antonio Filpi, an Acta scientist. Acta estimates that it can supply 1 metric ton per month of catalyst at about 5 euros per gram, about one-fourth the cost of a similar volume of platinum.
In order to circumvent hydrogen infrastructure issues, developers have proposed converting hydrocarbons into hydrogen inside the fuel cell itself. That has been questioned as possibly being less efficient than burning the hydrocarbons directly.
Two potential sources of hydrogen, natural gas and propane, already have distribution infrastructure systems in place. Two others, methanol and ethanol, are alcohols that could possibly use existing pipelines, delivery trucks, and storage tanks.
Powered by a Hydrogenics Corp. fuel cell, this airport tow tractor can generate enough power to pull a jetliner into its gate. The company plans a two-year test of 19 fuel cell forklifts.
Methanol has attracted the most attention as a possible fuel. Just a few years ago, the only economical way to re-form methanol was in refinery-sized chemical plants. Today, several companies can do it with fist-size systems that simplify processing and take only a few moments to reach operating temperatures.
Germany's Jülich Institute of Energy Research has unveiled its first forklift powered by a direct methanol fuel cell. Detlef Stolten, the lab's director, said, "With this prototype, we are now only a small step away from the commercialization of our fuel cell technology."
Some direct methanol fuel cells have already broken into the market. Michael Tausch, European key account manager of IdaTech LLC in Bend, Ore., said his company has installed several direct methanol fuel cells for backup power in telecommunications facilities.
The application is smart for all the right reasons. According to Tausch, a single 30-gallon barrel of methanol-water mixture replaces 18 cylinders of compressed hydrogen. "No hydrogen provider delivers to some of these remote facilities, but liquid is a lot easier and safer to transport and almost anyone can do it," he said.
Meanwhile, Protonex Technology Corp. of Southborough, Mass., expects to release a small, 250-watt direct methanol fuel cell for backup power, boating, and camping later this year.
Forklifts may take advantage of direct methanol. By eliminating the need to build on-site hydrogen plants, the technology would quickly improve fuel cell competitiveness.
So would new processes designed to purify hydrogen. The typical fuel cell requires hydrogen that is four to six nines (99.99 to 99.9999 percent) pure, explained Jeffrey Altman, president and CEO of Hy9 Corp. of Hopkinton, Mass. Industrial grade hydrogen, which sells for $28 per cylinder, is only 2-nines pure. Hydrogen costs $206 per cylinder for 4-nines and $320 for 6-nines purity.
The company has a membrane-based purifier that would enable fuel cells to run on cheaper grades of fuel. It would also give small hydrogen plants a more economical way of producing highly purified fuels.
It is hard to predict how the fuel cell future will evolve. Perhaps better and cheaper catalysts or direct methanol or natural gas technologies may bring fuel cells within reach of ordinary drivers.
In the meantime, though, developers are still testing technology and economics. This can take place only in the real world, where people make decisions based on returns on their investments. Because forklifts make the best economic case for any fuel cell mobility application, they're likely to provide answers that may lead to the fuel cell cars and buses of the future. Or warn us to take another direction.
Developers of a new commercial hybrid technology say it could double the speed of some of the most common industrial welding systems, even while it produces deeper welds and reduces splatter and heat distortion. Developed by former researchers from Ukraine's Paton Welding Institute, the technology is called Super-MIG and marries two welding technologies: plasma arc and metal inert gas, generally known as MIG, a variant of gas metal arc welding.
Super-MIG was designed to work with such available MIG welding systems as Lincoln, Miller, Panasonic, OCT, and ESAB. "If you already have a standard robotic welding cell, for approximately $50,000 you could add the system and run most operations nearly twice as fast," according to Ray Davis, sales and marketing manager of Welding Solutions Inc., the technology's North American sales agent.
This hybrid welding robot combines a conventional metal inert gas head with a plasma arc welder.
Super-MIG speeds welding because plasma and MIG share the load. MIG is often called "short circuit welding" because the weld wire and the workpiece carry opposite charges. When they touch, the weld wire expels metal from the workpiece. This carves a crater, which fills with molten metal and melted weld wire that cool to form the weld.
"A single weld wire has a lot of functions," Davis said. "We take away half that work by using plasma." Plasma is exceptionally good at making deep cuts into metal. Super-MIG aims its plasma ahead of the MIG welder. Like a plow, the plasma slices through the workpiece, creating a deep crater and a pool of molten metal before the MIG head gets there.
The MIG head then slices into the workpiece through the bottom of this "keyhole," penetrating three to four times deeper than MIG alone. "We've been successful welding 12-13 millimeters into steel," Davis said. "Standard MIG can do that, but you have to really slow the process down."
According to Davis, the process is very good for heavy structural welds, the types used in beams, heavy truck suspensions and frames, tube-to-tube welding, boilers, and heavy axle components.
Super-MIG has also produced true overlapping welds. They bond two or three pieces of flat steel plate to one another by welding together their centers. "Other systems say they can do it, but they'll put a slot or hole or some sort of joint preparation in the part and weld through that. We go right through the center without it. The only other systems that can do this are lasers," Davis said.
Lasers, however, cost upward of $1 million for starter systems, and require highly skilled operators and expensive consumables like optics. Super-MIG, Davis said, is for companies that may not need or cannot afford a laser, but want to run at faster speeds.
Metal or Plastic? Take Both
To introduce a new type of composite based on nanocrystalline metal cladding over a plastic core, DuPont Co. is partnering with Toronto-based Integran Technologies Inc. Potential uses range from under-hood and powertrain automotive parts to sporting goods.
According to Integran's president, Gino Palumbo, the composite combines the best properties of polymers and metals. Polymers are lightweight and easy to mold into intricate shapes that can consolidate a complex metal assembly into a single component. However, all but the most advanced and expensive polymers are prone to break down under abrasion and high temperatures. Metals, on the other hand, can be strong, hard, and heat-resistant, but also heavy and relatively hard to form into complex shapes.
MetaFuse composites combine the formability and light weight of plastics with the hardness and thermal conductivity of their nanocrystalline metal coating.
The new MetaFuse hybrids are billed as combining the strengths of metals and plastics while minimizing their weaknesses. Engineers can mold plastics into intricate, lightweight shapes. Coating them with nanocrystalline metals makes them much harder. It also boosts thermal conductivity, enabling MetaFuse parts to transport heat away from the plastic core and to extend their heat range.
Certainly, many companies have coated plastics with metal before. According to Palumbo, what makes MetaFuse different is the nanoscale nature of the coatings. Metals are made up of tiny crystalline grains. They deform (bend or break) when forces collide at weak points where the crystals are not aligned. These dislocations then move through the metal like a ripple running along the length of a carpet.
"You can push a ripple along a carpet more easily than lifting the entire carpet and moving it," Palumbo said.
The smaller size of nanocrystals gives dislocations less room to move. "The strength goes up by a factor of five," he said. Hardness also increases. According to Palumbo, the nanometals deliver these properties without the usual sacrifice of ductility. As a result, a thin nanometal coating can provide a surprising boost in properties.
Integran's first use of the technology came when it was a research group within the Canadian utility company Hydro Ottawa. It needed to resurface the interior of the water tubes running through its nuclear reactor without pulling them out.
"Using a conventional sleeve would have affected flow," Palumbo said. "Our nanocoating let us do the repair with one-quarter to one-fifth the amount of material. Those tubes have been in service for 15 years without a problem."
Palumbo expects his collaboration with DuPont to lead to many more applications in the near future. One of the most promising is automotive injector rails, which deliver pressurized fuel to the fuel injector. Affordable polymers cannot take the heat, and gasoline tends to permeate through them. MetaFuse's metal cladding dissipates heat before it weakens the polymer core and also prevents permeation.
Metal also could harden glass-filled nylon, making it competitive in powertrain components as well as in wheel hubs and door handles subject to stone chip damage and abrasion. DuPont and Integran are also working on sporting goods, such as bicycles and ski equipment, and on other consumer products.
The process itself doesn't use nanoparticles, obviating the potential health questions they raise. Instead, Integran deposits the coating from a solution at rates of 0.004 inch an hour. That sounds slow, but many applications require only 0.001 inch of coating (although others may use 0.03-0.04 inch or more). Still, as Palumbo notes, he can coat thousands of components in a single batch run.
Modern-day computer numerically controlled machines are no longer modern enough. The 50-year-old G and M codes that drive those machines can't transfer valuable geometric information from CAD and CAM systems, according to a group of experts who are advocating for widespread use of the recently approved STEP-NC standard. With the new standard, CAD and CAM applications have the capability to send product information to CNC machines.
But getting equipment and software suppliers on board with the new standard might take a while, the experts add. Still, if universally adopted, the standard could make subcontracting of machining across many manufacturing industries much easier.
Today's global engineering companies commonly pass CAD files back and forth. There are a number of ways for suppliers to translate their own CAD files into a format that original equipment manufacturers can read. Although the system is not always effective, suppliers and OEMs can almost get by. But engineering organizations can sometimes perceive CNC machines as the weak link that holds back a data stream that flows seamlessly from design to manufacturing, said Xun Xu, an associate professor of mechanical engineering at the University of Auckland in New Zealand.
Now comes STEP-NC, the machine-language standard first published by the International Organization for Standardization in 2003. Ten years in the making, STEP-NC includes tolerance and process planning capabilities that G and M codes can't accommodate, Xu said. He's looking at how STEP-NC can be adapted to all machining environments.
With the standard, a cutting tool is driven by geometric representation of the part to be made, said Martin Hardwick, president of STEP Tools Inc. of Troy, N.Y. His company sells software libraries that help companies write STEP-translation programs. It now sells similar tools for STEP-NC applications.
A machine tool creates a metal part. With the STEP-NC standard, the tool could read geometrical data from both CAD and CAM files.
Just as STEP has standardized the description of product data, allowing it to be passed with translation between varied CAD and CAM systems, STEP-NC is expected to streamline the passing of vital product data as well as geometric information across a global manufacturing chain, Xu said.
With STEP-NC, a machine tool can receive a file with extended product data, know what it means, and proceed to mill the piece without any more instructions. No more programming the machine tool for each job.
"Really, today, the guy on the CAM system generates codes for one specific CNC machine in his plant that he understands well," Hardwick said. "With geometric representation that machining program could be sent anywhere in the world and they could make it on their machine."
In terms of interoperability, the new standard promises to do for CNC tools what STEP and IGES have done for computer-aided design and computer-aided manufacturing, Hardwick said.
The ISO standard STEP, which stands for the "standard for the exchange of product model data," allows all CAD and CAM systems to exchange information, regardless of file format. The U.S. National Institute of Standards and Technology has a standard called initial graphics exchange specification—usually shortened to IGES—which also functions as a translator.
According to Hardwick, machine shops using the STEP-NC standard could reduce setup times by as much as 35 percent by seamlessly reading the 3-D product geometry and manufacturing instructions supplied by their customers. Original equipment manufacturers could reduce the time they spend preparing data for suppliers by 75 percent because they could share the design and manufacturing data straight from their databases.
A STEP-NC converted CAD file can whiz via Internet from a New York OEM to a California machine shop, which can then immediately start milling the part, Hard- wick said.
Given all these benefits, manufacturers and vendors should be lining up for STEP-NC, right? Not yet. Experts generally agree adoption isn't around the corner. It will happen eventually, although no one can yet say how long it will take.
Hardwick expects adoption of STEP-NC to mirror that of STEP, which users have been slow to accept. STEP for CAD became an ISO standard in 1995. Three years later, the large manufacturers—the early adopters, who saw the business case for STEP—began using the standard.
"In 2001 other enterprises started using it, and in 2003 all the complaints and whining disappeared as people realized what it did," Hardwick said. "There's a tremendous amount of resistance when these standards come out."
But more than users' reluctance holds back full-fledged adoption. CAM vendors will need to add system interfaces that write STEP-NC data while CNC machine makers will have to add interfaces to read data. Without significant customer demand for STEP-NC, vendors are hesitant to make the necessary investment in their systems, said John Callen, vice president of marketing at Gibbs and Associates of Moorpark, Calif., which sells CAM and NC programming software. Callen has partic-ipated in the STEP standards community and was a member of the STEP-NC industry review board for STEP Tools.
Vendors could also start making CNC machine tools that could read STEP-NC files. But the manufacturing world isn't exactly clamoring for those machines, so companies haven't stepped up to produce them.
"The audience that STEP-NC addresses is extremely conservative," Callen said. "Manufacturers say, if it ain't broke don't fix it. If they've got a system that works, they're not interested in jeopardizing that.
"A lot of them have spent years getting their operating procedures to the point they're fairly canned," he added. "Introduce STEP-NC and that throws a significant wrench in the works that they have to modify their system around. Most manufacturers will go, 'I want to do this why?' "
Gibbs and Associates' customers aren't yet asking for systems that can output to the new STEP-NC format, he added. When they do, Gibbs will provide them.
For his part, Hardwick thinks more companies will create their own postprocessors, based on STEP-NC libraries like those his company provides. These types of postprocessors offer a STEP-NC interface between CAM and CNC systems.
So STEP-NC proponents must lead the way by making the business case for the CNC standard. Boeing has taken a point position here, Callen said. Representatives from the aircraft company have been part of STEP-NC deliberations and recent prototype demonstrations.
An aircraft manufacturer has been particularly interested in a CNC-language standard because its CAM systems generate APT CL language, an intermediate file format that—when sent through a postprocessor—automatically generates machine-specific G codes, Callen said.
STEP-NC files could include information that APT CL files can't handle, such as part-model geometry, part dimensions, and tolerances, as well as machine probing commands. The manufacturer would like to work with the new standard on the company's next-generation aircraft.
Still Lost in Translation?
Should STEP-NC follow STEP's customer acceptance model as Hardwick predicts, it will likely face some adoption impediments along the way.
OEMs, well aware of STEP's limitations, don't make widespread STEP use easy, Callen said.
"In our industry, we see a lot of doublespeak when it comes to using STEP," he said.
A number of big players give lip service to STEP, he said. They agree the translation standard can be used to pass information from supplier to OEM. But, in reality, these large manufacturers require that suppliers use the same CAD system the OEM uses to avoid loss of data during translation.
"They're saying one thing and requiring something entirely different," Callen said. "Many say something about STEP in the contract, but suppliers are encouraged to adopt the same CAD system the OEM uses."
So STEP itself still isn't an optimal interoperability format and that'll likely be the case with STEP-NC, said Ken Tashiro, vice president and chief operating officer at Elysium Inc. of Southfield, Mich. The company sells CAD translators that Tashiro said can ease the headache that engineers face when translating STEP or IGES files.
The STEP and IGES translation programs have the same problems as human translators. Sometimes, there just isn't a one-to-one correlation between words or, in the case of CAD systems, pieces of product data, like geometry features or attributes.
And there's another issue as well. IGES and STEP standards have to evolve as fast as today's engineering technologies are evolving. And a slow-moving standards committee can't keep up.
Specialized translators like the ones Elysium makes are specifically written to translate files from one brand of software to another such as, say, UGS to Catia. Engineers who rely only on STEP or IGES as their translation tool of choice rather than on specialized translators can lose data in the translation process, Tashiro said.
Translators like Elysium's have been programmed to understand the characteristics of each of the supported CAD systems, keep on top of them, and make the required adjustments and corrections required for any data conversion, Tashiro said.
Elysium's STEP product is based on STEP tools.
"STEP Tools tells us how to build something, so we conform with STEP, and we add our own spice," Tashiro said. "If we know that some CAD format has something weird, like it calls a cylinder a truncated cone, but every other format calls it a cylinder, we know we should pop it into STEP as a cylinder."
Down the line, Tashiro expects to see specialized STEP-NC readers similar to the enhanced translators his company provides.
For his part, Xu is working to develop portable STEP-NC data that can be adapted to different machining environments. The key to this is to capture the information about machining tasks unambiguously and leave the decision on machining methods until the last moment when a machine tool is chosen.
So why don't software vendors get together and agree upon standard language? That way, a fillet would be a fillet— whatever CAD system it originated in, whatever CNC machine eventually machines the part.
The answer is easy, Tashiro said. For competitive reasons, vendors simply aren't willing to reveal their algorithms. That makes it impossible to transfer both files and codes among unlike systems without the use of a translator, whether STEP, or a spiced-up STEP.
Hardwick is hopeful that when manufacturers see STEP-NC in action, they'll get behind the new stan-dard. Next month in Dallas, STEP Tools will help to demonstrate the new standard for participants from Airbus, Lockheed Martin, Boeing, and Sandvik, among others.
"It'll be a fairly big demonstration to show the CAD/CAM vendors and hardware control vendors that all these people are interested in doing STEP-NC and to get them to move forward," Hardwick said. "But we still need to put forth more effort and get more vendors jumping in."
The road toward STEP-NC has been long and often filled with setbacks. But Callen said he hopes talk of the newly approved standard sparks user interest.
"We're getting there," he said. "We need to keep it in perspective, though. But I don't want to lose sight of the real benefits of STEP-NC and what it's done as far as making people aware of the type of product infor- mation that's required for next-generation manufacturing systems."