| You who read this, may be an engineer, a | | | | space craft, because there the pressure ratio to |
| mechanic, an inventor, a student, or even | | | | vacuum is infinite - many don't seem to know |
| someone without an engineering background. My | | | | that. In addition, even less known, is that the best |
| observation is that the general public has little | | | | sealing is obtained with a single, unbroken sealing |
| knowledge of basic science and even engineers | | | | line, ideally a circle. |
| and other professionals often lack in basic insights, | | | | Therefore, the reciprocating circular piston |
| in spite of being advanced in their specific fields. | | | | machine will always prevail over any rotational |
| This often leads to unfeasible projects and wrong | | | | displacement concept, that contains several |
| choices, based on wrong assumptions, that no | | | | broken (discontinuous) sealing lines. These |
| computer can correct. | | | | rotational concepts can be used and are used in |
| I myself am a graduated engineer on B.Sc level in | | | | low-duty applications, where they have their |
| both mechanics and electrics. Nevertheless, most | | | | advantages, such as in air-driven hand tools, |
| of what I know worth knowing as an engineer | | | | industrial compressors, etc, but not in heavy-duty |
| today, I learned from practical experience and | | | | combustion engines. This is why the Wankel never |
| backing it up with own theoretical studies | | | | became commercial, except a few years in cars |
| afterwards. It forced me to focus on basics. | | | | from German NSU, that went bankrupt on it in |
| When you have the basics right, the rest is just | | | | the 1970-ies. |
| methodology, where the computer can be very | | | | One can see the most 'horrible' designs in various |
| helpful, but don't let it "think" for you! | | | | patents, the worst I saw being an engine, |
| If you have no engineering background, why | | | | consisting of a torus shaped tube, with a slot |
| would you need to have some basic knowledge | | | | over its inner length to let through a piston rod, |
| of all this, you may ask? Well, we live in a | | | | attached to a circular piston moving in that torus, |
| technological society and so we are confronted | | | | while flat plates were sliding radially in and out the |
| with technological matters and products, that we | | | | torus to form alternate compression and |
| need to understand the basics of to make proper | | | | expansion chambers - at best a good |
| choices. Ever bought expensive "energy-saving" | | | | cream-wiper (but it got a gold medal in an |
| lamps, while in the same time needing to heat | | | | inventors contest - its glorious funeral)! |
| your home? Do you think hydrogen and/or fuel | | | | Many inventors have tried to find a linear |
| cells are energy sources? Do you think energy | | | | transmission, that can replace the pendulous |
| can be produced and consumed? Would you | | | | crankshaft. It has various disadvantages, such as |
| invest money in solar panels, or other renewable | | | | causing vibrations of higher order, but most of all |
| energy technology for your home? The more | | | | causing side-forces on the pistons, resulting in |
| these kinds of things apply on you, the more you | | | | excessive wear and leakage there. I once read a |
| need to read this article. | | | | statement from a development manager at |
| The Laws of Newton | | | | Volkswagen in Germany, that the crank |
| | | | mechanism alone stands for 20% of the fuel |
| The metric, or SI system of units is based on the | | | | consumption. All alternative designs I have seen, |
| laws of Newton and so is most of modern | | | | indeed convert the linear piston motion into a |
| mechanics and dynamics. They are essential for | | | | rotating one on the shaft and without causing side |
| basic understanding: | | | | forces on the piston, but instead they generate |
| - 1. A mass object persists in its momentary | | | | the same or higher side forces on sliding parts |
| motion to speed and direction, unless it is forced | | | | elsewhere in the design, causing excessive friction |
| to change it by external forces working on it. | | | | and wear there - definitely no fuel savings. I have |
| - 2. The acceleration of an object is proportional | | | | found a design that does not contain any sliding |
| with the force F working on it and inverse | | | | parts, but consists of rotating components only (I |
| proportional with its mass m. Hence, the acting | | | | got the idea, when I was with my kids in a |
| force is given by: F = m.a | | | | merry-go-round). Had I only come up with this a |
| - 3. A force acting on an object, will yield a | | | | good 100 years ago, I could have made it, but |
| counter force of the same strength in the | | | | now the pendulous crankshaft is so well |
| opposite direction: action = reaction. | | | | established in automated production lines, that it |
| Although these laws sound simple, they are often | | | | can't be changed any more. I almost hade it made |
| wrongly applied, or overlooked. Especially the third | | | | with Compair-Reavel in the UK, around 20 years |
| law appears to be the most fundamental one, still | | | | ago, but also they found it in the end too costly |
| not fully understood by Science and subject for | | | | too change their production line - my bad luck! |
| discussions on the highest levels (how can you | | | | Thermodynamics |
| move a table for example, as it pushes back with | | | | Another basic thing, often misunderstood, is that |
| the same force?). | | | | energy can't be "used up". Surely, the gasoline you |
| Power and Energy. | | | | put in your car is used up, but the energy it |
| Power and energy are very often mixed up. For | | | | developed is still there, to stay around for all |
| example a lightning, causing a tree to split into half, | | | | eternity. All the chemical energy that was stored |
| is very powerful, but it has very little energy, | | | | in the original fuel, is converted to heat. Firstly at |
| because it lasted only a fraction of a second. | | | | high temperatures in the car's engine, but then |
| Energy is the range of power and time. Power is | | | | decaying to heat at ambient temperature. The |
| expressed in Watt and energy in Joule - 1 Watt | | | | rest is also converted to heat by friction, the tires |
| thus is 1 Joule per second, inversely 1 J = 1 Ws | | | | on the road, the transmission, air resistance, etc. |
| (Watt second). If you during one hour would apply | | | | All energy that we "use" with our technology, |
| a power of 1000 Watt (1 kW = 1 kJ/s), which | | | | finally decays to heat at ambient temperature, |
| approximately is what a flat iron takes, the | | | | even the light from your lamps at home does |
| energy involved is 1 kWh and this is thus equal to | | | | that. |
| 3600 kJ. If you instead would develop that energy | | | | So is there the term "waste heat", as opposed to |
| in one second, the power becomes 3600 kW, or | | | | "useful heat".What is useful? Take "energy-saving" |
| 3.6 MW - a small power plant! If thus a lightning | | | | lamps for example. If you live in a cold climate, |
| would have a power of say 10 GW and lasted 1 | | | | where you have to heat your home, a normal |
| millisecond (it looks much longer, because of the | | | | cheap hot glowing light bulb actually delivers 100% |
| glowing air around it), it contained an amount of | | | | useful energy, 5% of which is light, the rest is |
| energy of just 10 MJ = 10,000 kJ, not more than | | | | heat, that helps heating your home, but this is not |
| 2.8 kWh, or to power a flat iron for around three | | | | what you are told. Only the 5% light is brought |
| hours! If you in brochures would read dimensions | | | | forward as "useful" and you are told that you are |
| like kilowatt per hour, or horsepower per hour, | | | | "wasting" 95% with a normal glow bulb. Only in |
| you can know that the author has no idea what | | | | warm climates, especially third-world countries |
| he/she is talking about. | | | | with very expensive electricity, or in cooled |
| Energy is also the range of force and traveled | | | | rooms, the use of energy-saving lamps makes |
| way. If you lift up a mass of 1 kg to a height of | | | | sense! |
| 1 meter, the force needed for that is the range | | | | The misconception by the public is that useful |
| of mass and gravity acceleration, as per Newton's | | | | energy is "consumed" and waste energy is not. |
| second law. On Earth, gravity acceleration is 9.8 | | | | The real situation is that the useful energy is just |
| meter per second square, which we can round to | | | | used, but not "consumed" and is wasted after |
| 10. The lifting force then becomes 10 kilogram | | | | usage just the same. That's why your energy bill |
| meter per second square, which is called the | | | | comes back every month - nothing of what you |
| Newton (N) and the work done is then 10 Nm | | | | used, is left. Therefore you read everywhere |
| (Newton meter), which is 10 Joule: 1 J = 1 Nm. | | | | about "energy production" and "energy |
| The same confusing exists around temperature | | | | consumption", not in the least used by decision |
| and energy. What would you rather have in your | | | | makers in energy politics! It indicates that there is |
| hand, a 1 inch red glowing sewing needle, or a 4 | | | | no basic understanding in public society, what |
| inch red glowing bolt? Though both have the | | | | energy is about and so unfeasible projects are |
| same temperature, the needle will just cause you | | | | initiated, wasting time and (your tax) money. |
| a blister, whereas with the bolt, you won't have a | | | | The First Law of Thermodynamics says that |
| hand any more. The bolt contains much more | | | | energy cannot be created (produced), nor |
| energy (more mass) than the needle and that | | | | destroyed (consumed). We can only convert |
| makes the difference, not the temperature. | | | | energy from one form to an other and the |
| If you would be interested in a solar panel to heat | | | | Second Law of Thermodynamics says that it all |
| water in your home, the temperature it can yield | | | | finally must decay to heat at ambient |
| is therefore not that important. You pay for | | | | temperature and so it does. Even though many |
| energy instead and that is what you want to | | | | know this, that is end of story for them, as far |
| save on. Ideally, a solar water heater should work | | | | as the First Law is concerned. However, the |
| on a low temperature, so it doesn't loose too | | | | scientific definition of the First Law says that if |
| much heat through its insulation and produce a | | | | you add energy to a system to bring it in an |
| larger water flow instead. You then save more | | | | other condition, you must remove the same |
| energy = money, because of the higher efficiency | | | | amount of energy to bring it back in the original |
| on which your solar panel works. To reach your | | | | condition. Naturally, because if we could remove |
| desired water temperature in the kitchen and | | | | more, energy would be created from nothing and |
| bathroom, you can heat additionally with say an | | | | if less, energy would disappear into nothing. This |
| electrical heater. Combination with a heat pump, | | | | formulation has great consequences, as follows: |
| also taking up heat from your warm waste | | | | Let's consider an ideal hydrogen (water) engine, |
| water, would give the absolute best results (but | | | | by which we pour water in it on one side and the |
| high installation costs). Read more about that at | | | | same water AND useful mechanical energy |
| the end of this article. | | | | comes out on the other side. Because the engine |
| However, manufacturers of solar panels optimize | | | | returns the same water as was applied (firstly as |
| on temperature, which is a good selling argument | | | | steam, but than condensing to water at ambient |
| for the energy-unaware public. At higher | | | | temperature), there cannot be a net output from |
| temperatures, the size and thus the costs of the | | | | the engine - it would have been created from |
| whole installation, including storage tank, become | | | | nothing. If there is an output anyway, this means |
| lower, which also sells better. They don't talk very | | | | that the according energy had to be applied as |
| much, or at all about efficiency, being the | | | | well, not only the water. Indeed, we must apply |
| relationship between how much solar energy hits | | | | energy to split the water in hydrogen and oxygen. |
| the solar panel and how much of that you can | | | | If that could be done at an efficiency of 100% |
| use in the end. They talk about capacity instead - | | | | (electrolysis has only 60%), then that energy |
| solar energy is "free"! | | | | could appear as mechanical work on the shaft. |
| Next to consider is Pressure. Usually it is that of a | | | | This then means that the hydrogen only was an |
| fluid, like a gas. It is expressed in Pascal (Pa) which | | | | energy converter, definitely not an energy source! |
| is force (N) per unit of area and thus 1 Pa = 1 N | | | | Hydrogen does not occur in free form on Earth, |
| sqm (Newton per square meter). Atmospheric | | | | like fossil fuels do and therefore hydrogen can |
| pressure at sea level is roughly 100 kPa, thus | | | | never be an energy source. Give me a dollar for |
| 100,000 N/sqm. In technical descriptions it is also | | | | every article that says different and I will be well |
| often called the bar - 1 bar is thus atmospheric | | | | off!If there would be a method to obtain free |
| pressure. Pressure can also be seen as stress in | | | | hydrogen at considerably less energy input than |
| materials, tension. In the SI system of units, | | | | what combustion with oxygen gives in output, |
| pressure and tension are thus both expressed in | | | | yes, then it would become an energy source, but |
| Pascal. | | | | such a method has not yet been found. |
| Then there is contact-pressure. This is what | | | | Instead of splitting water, hydrogen can be |
| makes a knife work. The sharper a knife, the | | | | obtained from natural gases, such as methane. It |
| smaller its edge area (A) is and for a given force | | | | shows however that the overall efficiency of |
| (F), the contact-pressure (F/A) becomes larger, | | | | such a hydrogen loop in a combustion engine |
| also expressed in Pascal. With this, all units in the | | | | would have a somewhat lower overall efficiency |
| SI-system are given. It has only three basic units, | | | | than using the natural gas (or bio-gas) directly in a |
| the kg for mass, the meter for length/distance | | | | combustion engine. Moreover, hydrogen is a very |
| and the second for time. No conversions are | | | | tricky gas to store and to handle. Not only is it |
| needed | | | | very explosive, but it tends to exude through |
| Circular Motions. | | | | most metals as well. It is very voluminous, around |
| From Newton's third law follows the perception | | | | ten times more than air and thus needs to be |
| that on an object in mechanical rotation, two | | | | brought on high pressures to keep the volume |
| forces are working, a centripetal one, pulling the | | | | down and that takes a lot of compression energy. |
| objects towards the center of rotation, and a | | | | Liquefying it would even take more energy, plus a |
| centrifugal one, tending to push it out radially | | | | temperature problem for storage as well. There |
| away from that center. If the mechanical contact | | | | are materials that can absorb hydrogen gas at a |
| with the center of rotation suddenly is broken, in | | | | lower temperature and give it off again at a |
| that very moment no forces are working on the | | | | higher temperature, surely the better way, but |
| object any longer and thus it will move as per | | | | also not very cheap and practical in a distribution |
| Newton's first law, meaning it keeps its speed in | | | | system. All together, there is no economy in |
| the direction it had in the moment just before | | | | hydrogen engines, but it may have an |
| losing contact. That speed was directed | | | | environmental advantage - the only viable |
| tangentially and thus the object will "fly out" in the | | | | argument for using it, provided the consumer |
| tangential direction, not radially. In fact, centrifugal | | | | wants to pay the higher costs, do you? |
| forces do not exist, because then there would be | | | | The same can be said from fuel cells, working on |
| no resulting force to keep an object in its circular | | | | hydrogen - they produce water (steam) and need |
| path - only the centripetal force exists. This is a | | | | a steady supply offresh hydrogen and oxygen to |
| hot discussion point in Science - Newton's third | | | | work continuously- whereto get how? Yes, the |
| law. | | | | energy that fuel cells are supposed to "produce", |
| Hence, when you are in a car that makes a sharp | | | | originally came from fossil fuels to manufacture |
| curve, your body does not push against the inside | | | | the input hydrogen. Can we call that |
| of the car (centrifugal), but the inside of the car | | | | "non-pollutant" energy? A fuel cell is NOT an |
| pushes your body into the curve (centripetal). As | | | | energy source, just an energy converter. |
| per Newton's first law, your body wants to keep | | | | The importance of using spontaneity in physical |
| its direction of motion, straight ahead, just before | | | | processes is largely unknown, because it has to |
| entering the curve - it's called inertia. There is only | | | | do with entropy, something not explained very |
| one force, the centripetal one (free motions in | | | | well in schools. So I had to learn in practice, by |
| gravitational fields, such as orbits of planets and | | | | trial and error, that if you want to separate fluids |
| satellites, are described in General Relativity, which | | | | from each other, you must try to find a design |
| we won't discuss here). | | | | by which this happens as spontaneously as |
| From this follows the notion of "inertial" systems, | | | | possible, for example with "smart" piping, rather |
| which are frames of reference in which Newton's | | | | than using filters. The more you try to force it |
| laws are valid. An accelerated system is thus not | | | | about with various design details, the more you |
| an inertial system, because motions described in it, | | | | will lose in efficiency - you "produce" entropy as it |
| would not follow Newtonian laws. This causes a | | | | wrongly is called. The more you force about a |
| severe point of confusion, as follows: | | | | process (introduce "irreversibilities", as it is called |
| If you are an inventor of "fantastic" mechanical | | | | correctly), the greater the change of entropy is, |
| machines, your really should understand the | | | | the lower the efficiency becomes. Entropy is an |
| implements of impulse. Impulse (p) is the amount | | | | essential part of the Second Law of |
| of motion, being the range of speed (v) and mass | | | | Thermodynamics, not to say the whole of it, but |
| (m), which is equal to the range of working force | | | | yet there is no general agreement among |
| (F) and the working time (t): F.t = m.v = p. An | | | | scientists, what entropy actually is - very |
| impulse has a direction, which (kinetic) energy has | | | | confusing. |
| not and therefore impulses can have a positive or | | | | The Second Law is actually not a "real" law, |
| a negative sign between opposite directions of | | | | because it is based on observations only, not on |
| motion. Because impulse is a function of force | | | | any physical principle. This means that if the |
| (the time-derivative of it), Newton's third law | | | | observations would change, the Second Law |
| requires that the sum of all impulses of moving | | | | would have to change too, but this hasn't |
| components within a system (machine) must be | | | | happened yet, which makes it a law. In everyday |
| zero. However, many inventors, not being aware | | | | life we experience that most things don't happen |
| of this, "create" a resulting impulse, that | | | | spontaneously, only accidents, or coincidences in |
| accelerates the system. | | | | general, do ("Murphy's Law"). If we want things to |
| What they do is mixing up reference systems | | | | happen, we usually have to do work for it. Hence |
| and impulse with energy. If you consider a | | | | we could formulate the Second Law as: "for free |
| mechanical system (machine), that has a certain | | | | only the Sun goes up". On the internet, this |
| total mass, but also internally moving parts, the | | | | formulation of the Second Law is widely violated |
| resulting impulse of those parts, the sum of all | | | | by millions of web sites, trying to let you believe |
| impulses, will be zero relative the system's center | | | | that for a small investment, you can become rich |
| of gravity, but not necessarily relative a resting | | | | very soon. But that is not engineering (rather |
| frame of reference (an observer) in which the | | | | "religion"), so I leave you with that. |
| whole system (machine) may be moving (at | | | | In engineering, especially when it comes to |
| constant speed). The sum of kinetic energy of all | | | | renewable energy sources, the Second Law is |
| the internally moving parts, is of course a positive | | | | also widely violated, or rather ignored. Oh yes, |
| value (negative energy is less than nothing). This | | | | solar energy is free, but you can't use it for free, |
| value is the system's internal (kinetic) energy. | | | | why not? Because it is widely spread in Nature |
| Since this internal energy is needed to keep the | | | | and thus the effort to collect it into one point of |
| internal parts moving, there cannot be any energy | | | | usage and to present it in a usable form, is very |
| left to accelerate the system (machine) as a | | | | large and you have to pay for that effort. Using |
| whole. On the contrary, energy must be applied all | | | | fossil fuels is cheaper and easier and that's what |
| the time to overcome the friction that the | | | | we do instead. The same would be valid for |
| internally moving parts are subjected to, | | | | nuclear power, but there the "environmentalists" |
| otherwise they would come to a halt. This applied | | | | have been successful to obstruct it - with thanks |
| energy converts to heat. | | | | from the Arab oil sheiks. |
| Sadly, there are several patents on according | | | | Renewable energy is something the Second Law |
| designs, claiming to be "inertial drives" for | | | | is very much against, because it wants to spread |
| space-ships or whatever. Their inventors, some | | | | it out in the environment, not to collect it for our |
| of which may have ruined their private economies | | | | use. Therefore these renewable energy sources |
| on this, were not confident with the basics of | | | | are high-entropy ones, meaning you must do a lot |
| dynamics, as outlined above. See some of those | | | | of work to make use of them (low efficiency). |
| unfortunate examples here: | | | | There is one exception though and that is |
| | | | hydro-electric power. The forces of nature |
| Mechanical Engineering Concepts | | | | actually do all the work for us, by collecting rain |
| | | | water in high situated reservoirs, ready for us to |
| Now, imagine you had a ball that is perfectly | | | | use; they are low-entropy sources. But also here |
| spherical and a table that is perfectly smooth, so | | | | the "environmentalists" choose to favor the oil |
| when the ball is placed on the table, the contact | | | | sheikhs instead. |
| area becomes a dimensionless point - zero | | | | Next would be heat pumps, which are inverted |
| whatever. Then the contact-pressure F/0 | | | | refrigerators. A heat pump absorbs heat from the |
| becomes infinite, regardless how light the ball is - | | | | environment, usually from the ambient air, by |
| something must break. No material could | | | | generating a cold surface there. This surface is |
| withstand an infinite contact-pressure and from | | | | small, but it actually collects heat from large, |
| this follows that not even with the most fantastic | | | | remote areas, brought by the wind. Also here, the |
| materials, yet to be developed, a frictionless | | | | forces of nature do the collecting work for us, a |
| machine could ever be built (that would require | | | | second exception on the rule (compare with a |
| ideal point and line contacts). | | | | storm blowing aside of your wind propeller, |
| Some inventors have a problem with that, like a | | | | without affecting it, or the Sun burning a hole in |
| patent I once saw, where a 15 cm (6 inch) | | | | the ground next to your solar panel, also without |
| diameter cylinder was rotating at 1500 rpm in a | | | | affecting it). |
| somewhat larger cylinder, supported by a number | | | | The heat pump, as the name says, pumps up the |
| of smaller rollers in the size of just a few | | | | ambient heat to a higher temperature that we |
| millimeters - it looked like a ball-bearing in cross | | | | can use, for example to heat water. Also its drive |
| section. These rollers would rotate at roughly | | | | power is given off as heat at usage temperature, |
| 50,000 rpm. You look in any bearing table what | | | | is thus no loss (where it is in a refrigerator) and |
| the admissible speeds are and you would see that | | | | so a heat pump can give off between 3 and 4 |
| this design exceeds the limits by far; self-destruct | | | | times more energy than what it takes to run it. If |
| through friction! | | | | all the billions of dollars that to date and ongoing |
| Another problem that many inventors have is | | | | are wasted on wind propellers and solar collectors |
| judging leakage potential. Leakage is a function of | | | | of various kinds, would have been used to |
| pressure ratio, not of pressure difference and it | | | | provide all households with heat pumps, many |
| varies to the third power with the clearance gap | | | | power plants could have been shut down by now |
| between the boundaries. It means that the same | | | | and no more oil would be burned in homes for |
| sealing device, that would leak in an however | | | | heating. This however is a truth with modification. |
| deep submerged submarine, would leak more in a | | | | |