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5th November 2021, 19:12 | #21 | |
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Rover 75CDT, Jaguar XF-S 3.0V6, V'xhall Omega V6 Estate, Twintop 1.8VVT, Astra Estate and Corsa 1.2 Join Date: Dec 2007
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Quote:
Fortran 77 was my favourite language, having used it to write a lot of signal processing software incldung FFT, digital filter design, speech encoding/decoding etc. Modern languages make it too easy! |
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5th November 2021, 21:55 | #22 | |
Gets stuck in
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Quote:
This brings back fond memories of building / hacking away parts of a Reliant 850cc engine for one of the Branches of their car club. The unit was a display engine driven by an electric motor through the ring gear. Acrylic components permitted a view of two of the cylinders from the crank shaft to valve gear the cut away at the rear gave a view of the push rods and the acrylic rocker cover let you see the valve gear operating . The bell housing was 50% cutaway again with an acrylic insert to allow the flywheel and clutch to be seen. The engine set up had no compression but did have a clear distributor and the ignition system had a power supply so the spark could be seen on the compression stroke prior to the power stroke. I built this back in the Eighties, I wonder what ever happened to it.? It let you see how a internal combustion engine worked, and was mounted in a rolling chassis from a Reliant Kitten. That was transported on top of a 6’x4’ trailer, round the car shows the Club attended for several years. Sent from my iPad using Tapatalk |
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7th November 2021, 06:17 | #23 | |
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The science bit
Quote:
A flywheel is a mechanical device which uses the conservation of angular momentum to store rotational energy; a form of kinetic energy proportional to the product of its moment of inertia and the square of its rotational speed. In particular, if we assume the flywheel's moment of inertia to be constant (i.e., a flywheel with fixed mass and second moment of area revolving about some fixed axis) then the stored (rotational) energy is directly associated with the square of its rotational speed. Since a flywheel serves to store mechanical energy for later use, it is natural to consider it as a kinetic energy analogue of an electrical inductor. Once suitably abstracted, this shared principle of energy storage is described in the generalized concept of an accumulator. As with other types of accumulators, a flywheel inherently smoothes sufficiently small deviations in the power output of a system, thereby effectively playing the role of a low-pass filter with respect to the mechanical velocity (angular, or otherwise) of the system. More precisely, a flywheel's stored energy will donate a surge in power output upon a drop in power input and will conversely absorb any excess power input (system-generated power) in the form of rotational energy. Common uses of a flywheel include:
Flywheels are often used to provide continuous power output in systems where the energy source is not continuous. For example, a flywheel is used to smooth fast angular velocity fluctuations of the crankshaft in a reciprocating engine. In this case, a crankshaft flywheel stores energy when torque is exerted on it by a firing piston, and returns it to the piston to compress a fresh charge of air and fuel. Another example is the friction motor which powers devices such as toy cars. In unstressed and inexpensive cases, to save on cost, the bulk of the mass of the flywheel is toward the rim of the wheel. Pushing the mass away from the axis of rotation heightens rotational inertia for a given total mass. References · "Flywheels move from steam age technology to Formula 1". Archived from the original on 2012-07-03. Retrieved 2012-07-03.; "Flywheels move from steam age technology to Formula 1"; Jon Stewart | 1 July 2012, retrieved 2012-07-03 ·· "Breakthrough in Ricardo Kinergy 'second generation' high-speed flywheel technology". 2011-08-21. Archived from the original on 2012-07-05. Retrieved 2012-07-03., "Breakthrough in Ricardo Kinergy ‘second generation’ high-speed flywheel technology"; Press release date: 22 August 2011. retrieved 2012-07-03 ·· Lynn White, Jr., "Theophilus Redivivus", Technology and Culture, Vol. 5, No. 2. (Spring, 1964), Review, pp. 224–233 (233) ·· Letcher, Trevor M. (2017). Wind energy engineering: a handbook for onshore and offshore wind turbines. Academic Press. pp. 127–143. ISBN 978-0128094518. Ibn Bassal (AD 1038–75) of Al Andalus (Andalusia) pioneered the use of a flywheel mechanism in the noria and saqiya to smooth out the delivery of power from the driving device to the driven machine ·· Ahmad Y Hassan, Flywheel Effect for a Saqiya. ·· "Flywheel" (PDF). themechanic.weebly.com. ·· Shabbir, Asad. "The Role of Muslim Mechanical Engineers In Modern Mechanical Engineering Dedicate to12th Century Muslim Mechanical Engineer" (PDF). Islamic Research Foundation International, Inc. ·· Lynn White, Jr., "Medieval Engineering and the Sociology of Knowledge", The Pacific Historical Review, Vol. 44, No. 1. (Feb., 1975), pp. 1–21 (6) ·· Dunn, D.J. "Tutorial – Moment of Inertia" (PDF). FreeStudy.co.uk. p. 10. Archived (PDF) from the original on 2012-01-05. Retrieved 2011-12-01. ·· "Flywheels: Iron vs. Steel vs. Aluminum". Fidanza Performance. Archived from the original on 10 October 2016. Retrieved 6 October 2016. ·· Ashby, Michael (2011). Materials Selection in Mechanical Design (4th ed.). Burlington, MA: Butterworth-Heinemann. pp. 142–146. ISBN 978-0-08-095223-9. ·· Totten, George E.; Xie, Lin; Funatani, Kiyoshi (2004). Handbook of Mechanical Alloy Design. New York: Marcel Dekker. ISBN 978-0-8247-4308-6. ·· Kumar, Mouleeswaran Senthil; Kumar, Yogesh (2012). "Optimization of Flywheel Materials Using Genetic Algorithm" (PDF). Acta Technica Corviniensis-Bulletin of Engineering. Archived (PDF) from the original on 1 November 2015. Retrieved 1 November 2015. ·· "Flywheel Energy Storage, UPS, Battery-Free, Active Magnetic Bearing, Magnetic Bearings, Kinetic Energy, Magnet Motor Generator, Bi-Directional Power Converter - Calnetix". www.calnetix.com. Archived from the original on 1 November 2017. Retrieved 2 May 2018. ·· "Flywheel Energy Calculator". Botlanta.org. 2004-01-07. Archived from the original on 2011-07-25. Retrieved 2010-11-30. ·· "energy buffers". Home.hccnet.nl. Archived from the original on 2010-11-26. Retrieved 2010-11-30. ·· "Message from the Chair | Department of Physics | University of Prince Edward Island". Upei.ca. Archived from the original on 2010-04-30. Retrieved 2010-11-30. ·· "Density of Steel". Hypertextbook.com. 1998-01-20. Archived from the original on 2010-11-25. Retrieved 2010-11-30. ·· Flywheel Rotor And Containment Technology Development, FY83. Livermore, Calif: Lawrence Livermore National Laboratory , 1983. pp. 1–2 ·· Li, Xiaojun; Anvari, Bahar; Palazzolo, Alan; Wang, Zhiyang; Toliyat, Hamid (2018-08-14). "A Utility Scale Flywheel Energy Storage System with a Shaftless, Hubless, High Strength Steel Rotor". IEEE Transactions on Industrial Electronics. 65 (8): 6667–6675. doi:10.1109/TIE.2017.2772205. S2CID 4557504. ·· Li, Xiaojun; Palazzolo, Alan (2018-05-07). "Multi-Input–Multi-Output Control of a Utility-Scale, Shaftless Energy Storage Flywheel With a Five-Degrees-of-Freedom Combination Magnetic Bearing". Journal of Dynamic Systems, Measurement, and Control. 140 (10): 101008. doi:10.1115/1.4039857. ISSN 0022-0434. ·· Genta, G. (1985), "Application of flywheel energy storage systems", Kinetic Energy Storage, Elsevier, pp. 27–46, doi:10.1016/b978-0-408-01396-3.50007-2, ISBN 9780408013963 ·· Egorova, Olga; Barbashov, Nikolay (2020-04-20). Proceedings of the 2020 USCToMM Symposium on Mechanical Systems and Robotics. Springer Nature. pp. 117–118. ISBN 978-3-030-43929-3. ·· [1], "Маховик", issued 1964-05-15 ·· "Technology | KEST | Kinetic Energy Storage". KEST Energy. Retrieved 2020-07-29.
Dual mass flywheel production first started in the 1980's. They were originally developed to address the escalation of torque and power, especially at low revs on new higher horsepower vehicles and to increase comfort for the driver. A Dual Mass Flywheel essentially consists of two components (the primary & secondary mass) linked together by a damping mechanism consisting of arc springs and spring guides and located by a central bearing/bushing. The damping springs inside the flywheel allows the D.M.F to filter the torsional engine vibrations away from the gearbox and reduces the load on the transmission line. The larger damper in the D.M.F is better suited for filtering the engine vibrations (especially needed for turbo diesel engines). The dual mass flywheel allows driving at lower engine speeds thus increasing engine efficiency. This in turn saves fuel and reduces CO2 emissions as well as any vibration that can cause “gear rattling” & “body booms”. [IMG]file:///C:\Users\User\AppData\Local\Temp\msohtmlclip1\01\c lip_image002.jpg[/IMG] As with any wearing component, over time the damping springs and mechanism begin to wear and weaken. As the mileage increases, the damping mechanism becomes weaker to the point where the movement between the primary and secondary masses increases to where it no longer functions to the best of it’s ability and its performance dramatically reduces. When this happens the flywheel will no longer be able to adequately filter out violent variations of torque or revolutions that could cause an unwanted vibration or rattle when driving. These vibrations can usually be felt on the floor of the car and are due to the failure of the springs and other internal components. This leads directly to the flywheel’s inability to dampen the tremors with use and it must be replaced. Causes Of Dual Mass Flywheel Failure There are many reasons why a dual mass flywheel can fail. The main reasons are: Heat - Excessive heat is a big cause of most dual mass flywheel failures. A slipping clutch generates heat; if your clutch is worn, you can still save the flywheel if you get the clutch replaced early enough. Abuse - Engaging the clutch violently can damage the internal mechanisms of the flywheel. There's a happy medium between smoothly engaging the clutch and excessively sliding the clutch when disengaging it, if you find that point, you can avoid premature failure Type of driving - A flywheel can last much longer if a vehicle is primarily used for motorway driving where gear changes are considerably less than city driving. Like any other part on a car, the driving conditions can make a big difference on when a dual mass flywheel fails. Mileage - At some point every wearing part is going to fail from natural use. Once a component comes to the end of its natural life cycle it will need to be replaced. Material selection Flywheels are made from many different materials; the application determines the choice of material. Small flywheels made of lead are found in children's toys.[citation needed] Cast iron flywheels are used in old steam engines. Flywheels used in car engines are made of cast or nodular iron, steel or aluminum.[10] Flywheels made from high-strength steel or composites have been proposed for use in vehicle energy storage and braking systems. The efficiency of a flywheel is determined by the maximum amount of energy it can store per unit weight. As the flywheel's rotational speed or angular velocity is increased, the stored energy increases; however, the stresses also increase. If the hoop stress surpass the tensile strength of the material, the flywheel will break apart. Thus, the tensile strength limits the amount of energy that a flywheel can store. In this context, using lead for a flywheel in a child's toy is not efficient; however, the flywheel velocity never approaches its burst velocity because the limit in this case is the pulling-power of the child. In other applications, such as an automobile, the flywheel operates at a specified angular velocity and is constrained by the space it must fit in, so the goal is to maximize the stored energy per unit volume. The material selection therefore depends on the application.[11] The table below contains calculated values for materials and comments on their viability for flywheel applications. CFRP stands for carbon-fiber-reinforced polymer, and GFRP stands for glass-fiber reinforced polymer. Material Specific tensile strength ( k J k g ) {\displaystyle \left(\mathrm {\frac {kJ}{kg}} \right)} Comments 200–2000 (compression only) Brittle and weak in tension, therefore eliminate Composites: CFRP 200–500 The best performance—a good choice Composites: GFRP 100–400 Almost as good as CFRP and cheaper Beryllium 300 The best metal, but expensive, difficult to work with, and toxic to machine High strength steel 100–200 Cheaper than Mg and Ti alloys High strength Al alloys 100–200 Cheaper than Mg and Ti alloys High strength Mg alloys 100–200 About equal performance to steel and Al-alloys Ti alloys 100–200 About equal performance to steel and Al-alloys Lead alloys 3 Very low Cast Iron 8–10 Very low[12] The table below shows calculated values for mass, radius, and angular velocity for storing 250 J. The carbon-fiber flywheel is by far the most efficient; however, it also has the largest radius. In applications (like in an automobile) where the volume is constrained, a carbon-fiber flywheel might not be the best option. Material Energy storage (J) Mass (kg) Radius (m) Angular velocity (rpm) Efficiency (J/kg) Energy density (kWh/kg) 250 0.0166 1.039 1465 15060 0.0084 Aluminum Alloy 250 0.0033 1.528 2406 75760 0.0421 Maraging steel 250 0.0044 1.444 2218 56820 0.0316 Composite: CFRP (40% epoxy) 250 0.001 1.964 3382 250000 0.1389 Composite: GFRP (40% epoxy) 250 0.0038 1.491 2323 65790[13] 0.0365 Table of energy storage traits Flywheel purpose, type Geometric shape factor (k) (unitless – varies with shape) Mass (kg) Diameter (cm) Angular velocity (rpm) Energy stored (MJ) Energy stored (kWh) Energy density (kWh/kg) Small battery 0.5 100 60 20,000 9.8 2.7 0.027 Regenerative braking in trains 0.5 3000 50 8,000 33.0 9.1 0.003 Electric power backup[14] 0.5 600 50 30,000 92.0 26.0 High-energy materials For a given flywheel design, the kinetic energy is proportional to the ratio of the hoop stress to the material density and to the mass:
For a given design the stored energy is proportional to the hoop stress and the volume: it is true. The AA comment quote: AA technical specialist Vanessa Guyll to explain the issue. She said: “David's Vectra uses a complex dual-mass flywheel. These smooth out the vibrations from modern, powerful diesel engines. They're not as reliable as solid flywheels, but should last at least four to five years.”28 Mar 2012 I am hoping the text I have lifted from my word document has come over to this platform. Alan |
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7th November 2021, 09:08 | #24 |
This is my second home
Rover 75 CDT Manual Connoisseur SE, Rover 75 CDT Automatic Connoisseur SE & a Freelander Td4. Join Date: Jul 2009
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I still use an old Colourtune plug to set up the carb on my Norton - fascinating to be able to look into each cylinder and actually see the fuel igniting.
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7th November 2021, 09:25 | #25 |
This is my second home
Rover 75CDT, Jaguar XF-S 3.0V6, V'xhall Omega V6 Estate, Twintop 1.8VVT, Astra Estate and Corsa 1.2 Join Date: Dec 2007
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Good morning, Alan.
Thanks for posting the detail, on which I will make a number of observations. 1. The AA person did not say that DMF last 4-5 years as originally stated. She said 'They're not as reliable as solid flywheels, but should last at least four to five years.”28 Mar 2012' as you correctly note above. I read this as a general comment, not based on detailed information, and one which indicates that they are highly reliable. Other than that, the statement is of zero value. 2. I do not see a characterised mathematical model of the physics of a solid flywheel vs a DMF. Therefore, based on what has been posted, it can not be stated that a DMF offers no advantage over a solid flywheel. 3. I agree with you that a flywheel is a mechanical low-pass filter as a first order approximation. But, a DMF, due to the presence of the additional reactive (inductive) components, will be a more effective filter if properly designed. There is nothing in what you have posted to convey the argument that a DMF does not offer advantage over a solid flywheel. My apologies if there is more to come and I am jumping the gun. Here is a very readable paper on DMF from Schaeffler, the parent company of LUK. https://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/symposia_1/downloads_11/4_DMFW_1.pdf Maninder. |
7th November 2021, 09:29 | #26 |
This is my second home
Rover 75CDT, Jaguar XF-S 3.0V6, V'xhall Omega V6 Estate, Twintop 1.8VVT, Astra Estate and Corsa 1.2 Join Date: Dec 2007
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8th November 2021, 04:31 | #27 |
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Me also
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8th November 2021, 05:17 | #28 |
Gets stuck in
75 Tourer Automatic conn, 75 Saloon Automatic Conn, The Monograme Spice Tourer Join Date: Jun 2014
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That is me just lost another chunk of data for the post, Sorry Guys I am unable at the moment to copy or even cut and paste the bit I wanted. I had just spent 2 hours retyping part of the data and it has vanished with out trace. I am going to blame my age.
My apologies to all Alan |
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