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#51 2021-04-29 20:23:00

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 21,841

Re: Fixing Americas car industry

The technology is simular to the cellphone charging pad in which the energy sent in is twice as much due to converting the energy from a DC source into AC for the device to pick up  while setting on it. The device however only recieves half of the energy to charge with. The energy drops with seperation growth of distance between the sender and reciever coils. For building vehicles that distance is going to be hard to maintain as the vehicles we use are not all the same with wheel clearances not to mention tire wheel rim sizes.

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#52 2021-04-30 21:18:39

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 21,841

Re: Fixing Americas car industry

This does not bode well 1 in 5 electric vehicle owners in California switched back to gas because charging their cars is a hassle, new research shows

Fast charge low costs....

still are getting it wrong

https://autos.yahoo.com/citroen-ami-app … 00683.html

1,070-pound weight. Citroën quotes a 43-mile driving range from a 5.5-kilowatt-hour lithium-ion battery pack, and a top speed of precisely 27.9 mph on flat ground. It was developed solely for short, urban trips at low speeds.

Stop and go streets this is useless...

can not even use it on the highway....

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#53 2021-04-30 22:05:35

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 5,751

Re: Fixing Americas car industry

For SpaceNut ... the run halted again ... I had time to look at your post here ... Actually, 43 miles on city streets would just about cover most of my needs.  The key question I would have is what is the cost of a vehicle new.  I also wonder if the insurance cost might be lower, since the gas vehicle I have is necessarily insured at the full rate for a vehicle that can do a lot of damage. 

Regarding the halt ... I have multiple wireless routers, and was using one some distance from the laptop.  I just changed to one that is a few feet away, and has a 100% signal.  I'll bet performance will improve!

(th)

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#54 2021-05-01 06:43:10

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 858

Re: Fixing Americas car industry

Fast charging batteries would place extreme demands on the electric grid.  If transportation is fully electrified, it would just about double total daily electricity demand.  Imagine how much generating capacity would be needed when everyone plugs their fast charging cars in at 7pm and charges them in just two hours.  To meet those sorts of demand peaks, most grid operators build open cycle gas turbines.  They have low capital cost and ramp up to full load very quickly, within minutes.  They are almost certainly what would end up being used.  Fast charging electric vehicles would simply shift combustion from the vehicle to the powerplant.


Interested in space science, engineering and technology.

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#55 2021-05-01 07:06:51

louis
Member
From: UK
Registered: 2008-03-24
Posts: 6,300

Re: Fixing Americas car industry

That's why they want "smart meters" in every household. They are clearly going to have sharply differential rates through the day/night. The aim would be to encourage people to put their vehicle charging on a timer and I expect timers will be incorporated in future models, so you can plug in and instruct "begin charging at 3am" or whatever.


Calliban wrote:

Fast charging batteries would place extreme demands on the electric grid.  If transportation is fully electrified, it would just about double total daily electricity demand.  Imagine how much generating capacity would be needed when everyone plugs their fast charging cars in at 7pm and charges them in just two hours.  To meet those sorts of demand peaks, most grid operators build open cycle gas turbines.  They have low capital cost and ramp up to full load very quickly, within minutes.  They are almost certainly what would end up being used.  Fast charging electric vehicles would simply shift combustion from the vehicle to the powerplant.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#56 2021-05-01 19:21:33

kbd512
Administrator
Registered: 2015-01-02
Posts: 4,190

Re: Fixing Americas car industry

SpaceNut,

The most practical answer is a heavily boosted, smaller displacement internal combustion engine paired with super capacitors and an electric powertrain that eliminate the driveshafts, transmissions, and transfer cases.  There's no technological reason why smaller displacement combustion engines can't power heavy vehicles if the acceleration energy is provided by a super capacitor bank, rather than the engine itself.  This is an achievable automotive technological advance that doesn't require non-existent battery technology.  Any type of battery using current or projected near-term battery technology is impractically heavy for delivering continuous power to a land motor vehicle that is primarily overcoming rolling resistance and aerodynamic drag at constant speed.

'In Pursuit Of Perfection' Carbon Fibres Drive The Future Of Lightweight Cars

The admission here from the CFRP automotive technology promoter is that if vehicle weight only accounts for 23% of a land-based motor vehicle's fuel consumption, then the other 77% is overcoming rolling resistance and aerodynamics.  Those problems cannot be solved by using a material that requires 14 times as much energy to produce, per unit weight, as steel.  The practical achievable weight reduction using CFRP is 50%, but the energy input is more than double what steel requires, so 1,555kWh for the 320kg of steel (20MJ/kg) vs 9,824kWh for the 125kg of CFRP (283MJ/kg).  That's the energy required to make the carbon fibers, not the energy required for the epoxy and molding processes.  If you figure that the composite is around 60% fiber and 40% epoxy, then it's obviously less energy than the 9,824kWh figure would suggest but then the energy for making the epoxy, curing the part, and the 10% scrap rate has to be added.  So, bare minimum, the CFRP structure consumes more than twice as much energy as an equivalently strong steel structure.

Argonne National Laboratory - Energy Systems Division - Lightweight Materials for Automotive Application

Clemson University TigerPrints - Mechanical Engineering - Department of Automotive Engineering - Cost Estimation Model for PAN Based Carbon Fiber Manufacturing Process

My thinking on the general utility of applying aerospace materials and fabrication technology to land motor vehicles has changed as I've spent more time analyzing the average lifespan of consumer land motor vehicles.  The heavy duty trucks are a different issue.  To recycle CFRP fibers into new CFRP fibers, requires almost as much energy as it took to produce them from virgin stock to begin with, because the recycling process is basically the production process.  Older consumer vehicles are typically replaced with new vehicles every 3 to 5 years, so it's unlikely that substantial total energy consumption can be saved through a reduction of gasoline consumption associated with lighter CFRP vehicle chassis by switching to aerospace materials.

Now that we have ultra-high strength steel that competes with 7075 Aluminum on a per-unit-mass tensile strength basis, we've reached a point of diminishing returns on lightweight but strong materials with low embodied energy.  This is a necessary compromise because we will scrap nearly all of them in a few short years.  What this actually suggests is that we operate a lesser number of more durable steel vehicles that have hybrid powertrains.  The market seems to suggest that very small compact vehicles work best for urban transport and much larger trucks or SUVs work best for rural areas where the owner / operator has to haul a variety of cargo to / from home.

Audi's switch back to steel part of growing trend

The LS series V8s are used specifically for their ability to accelerate heavy vehicles quickly, but that is not the only technologically and economically viable solution.  The LS tends to expend more fuel to keep the rotating mass spinning at all times, even with its displacement-on-demand technology, irrespective of the load placed upon it.  The problem with displacement-on-demand is the fact that the remaining 4 cylinders must keep the engine spinning at a given RPM, merely touching the throttle disables the system, greatly diminishing its utility for economizing on fuel consumption, and it both complicates the engine's valve train and becomes a new failure mode for the engine.

The 420hp LS V8 engine in our Escalade provides 20mpg to 25mpg on the highway.  A small cast iron 50hp inline-4 that's designed to run at WOT, when paired with a battery pack or super capacitor pack, could also provide the necessary acceleration to 70mph, with both less weight and less total system complexity, by eliminating the heavy duty 10 speed transmission, driveshaft, rear differential, and transaxle.  This single change would at least double the fuel economy of the vehicle, especially in stop-and-go traffic, but also on the highway due to the drastic reduction in rotating mass.  The 4-banger and fuel tank would be relocated to the engine bay, the generator that the engine powers would charge the battery pack located where the large gas tank was previously located, and a pair of electric hub motors would directly drive the rear wheels.

Apart from racers, most other people care about fast acceleration to maximum legal road speeds.  I want to accelerate quickly and then burn as little fuel as possible at all other times.  I can't do that with a V8, but if I had a small battery pack or super capacitor pack, then I could use the stored energy to accelerate quickly and then loaf along using 25hp.  I don't care if the vehicle can ultimately go 160mph with a V8.  That's nonsense.  It's not legal to do and the vehicle is marginally controllable at 80mph.  Going much faster than that is unacceptably dangerous to me.

A few notes on how aircraft differ in service life, as compared to land motor vehicles:

Aircraft are typically operated for a minimum of 10 to 20 years, with most light aircraft operated for many decades more.  Substantial numbers of Aluminum airframes from the 1960s / 1970s / 1980s are still in operation today, due to the high cost of labor in modern times.  In many cases there are no functional differences in the airframes produced 50 years ago, as is the case with many of Cessna's light aircraft.  Cessna 172 model airframes, the most produced aircraft of all time, have been produced by the thousands since the 1950s, with the only differences being glass cockpit avionics in the most recent examples produced (same Aluminum alloys, same airframe design down to the rivet placement, same engine, same propeller, same fuel used, same hand assembly methods, only modern digital avionics that weigh less than the analog steam gauges).  Production cost rose from $25K back in the 1950s to over $500K for current year production.  If there's still service life left in the wing spars, then Aluminum aircraft are repaired and pressed back into service.  That simply does not happen with land motor vehicles.  In point of fact, all-Aluminum airframes are restored by addressing corrosion issues with sanding and application fresh paint after replacing badly corroded metal with new metal, in accordance with FAA-issued or manufacturer-issued ADs (Airworthiness Directives).  Military aircraft like the A-10 or C-130 receive completely new wings, if need be, and we operate very few of those on account of the associated manufacturing, engine maintenance, fuel, and training costs.  If you have the steel assembly jigs, or better yet, matched-hole-drilled parts, then you can make new parts until you run out of Aluminum.

In contrast to aeronautical designs that only change enough to remain airworthy (such as slightly stronger wing spars or better corrosion protection or replacement of defective parts), automotive designs frequently incorporate major changes every few years, so very little of the embodied energy and human labor cost sunk into design and production setup can be recovered over decades of production.  This is one of the major reasons why Ford / GM / Chrysler / VW / Mercedes-Benz / BMW / Honda / Toyota / Mazda / Nissan / Suzuki mandate that different brands use the same engine and computer control technology.  Tesla is a notable exception that has sworn off constant major changes and introduction of completely new models in favor of improved manufacturing methods and engineering of powertrain systems into the same basic designs, which is ultimately the correct approach to sustainable automotive engineering at a global scale that eventually reduces rather than continually increases production and repair costs.

The very first certified all-composite airframe aircraft ever produced, the Windecker Eagle (USAF designation YE-5; all rights now owned by a Chinese entrepreneur enamored with the design), is still in service, for example.  It was restored a few years back, rather than build an entirely new airframe, at substantially greater cost.  That composite airframe cost $20M to certify with the FAA back in 1989.  A grand total of 2 prototypes and 6 production airframes were produced before Windecker Industries went bankrupt, proving the timeless adage in aviation that if you want to make a small fortune from your aircraft design, then start with a much larger fortune.

In the intervening years, composite aircraft construction has greatly improved, to the point that all commercial airliners are now mostly composites by weight.  Burt Rutan's series of mold-less GFRP composite airframes were capable of marginally improved speed and range at weights and power output levels below what was achievable using all-Aluminum airframes.  His CFRP airframes were even more performant than their all-Aluminum contemporaries.  Much of this was attributable to the aerodynamics improvements that Burt Rutan, his team at Scaled Composites, and the aerodynamicist John Roncz were able to achieve with truck loads of investment money provided by the US Air Force, primary defense contractors, and private investors.  The basic airframe designs were also quite good at maximizing strength for a given weight, with a keen eye to the practical ability to fabricate composite parts with minimal tooling.  Similarly, Windecker Industries had lots of US Air Force money backing it.  As GW already noted, the composite airframe parts used in radomes and antenna fairings, prior to the advent of all-composite airframes in 1970s were comparatively low complexity, small, and absurdly expensive.  Such parts are still far more expensive than sheet metal equivalents today, on account of the energy and labor required to produce them.  They're not things that can be thrown away or recycled every few years because the owner wants something new.  Steel foams and honeycomb structures offer a more practical weight compromise between composites or light alloys, while maintaining ease of recycling, as compared to traditional thicker and heavier sheet metal stampings.

A good analog for the 4-seat all-composite Windecker Eagle is the 6-seat all-Aluminum Piper Piper PA-32 Cherokee Six.  Both airframes are equipped with 300hp class Continental IO-520 or Lycoming IO-540 engines.  Piper delivered 7,842 PA-32 airframes between 1965 and 2007.  The Cherokee Six is 36mph slower than the Eagle at cruise speed and has a range of 840 miles vs 1,232 miles, but the PA-32-300LD (Low-Drag variant of the PA-32; only one built) proved that the airframe could achieve significantly greater range and a higher cruise speed if additional cost was devoted to the airframe structures.  This was deemed uneconomical, so it wasn't pursued.  The retractable gear Piper PA-32R Saratoga has a cruise speed that's only 24mph slower than the Eagle, is a 7-seat airframe, has a 200 pound increased max gross weight, and a range of 1,007 miles.  The real story here is that 1950s-era all-Aluminum airframes were considerably more capable than all-GFRP airframes built 20 to 40 years later when equipped with the same types of power plants.  The Saratoga also has a 94 gallon fuel capacity vs the Eagle's 86 gallon fuel capacity.

The modern fixed gear all-composite 4-seat Cirrus SR22 achieves equivalent range and speed equivalent to the Windecker Eagle, equivalent fuel burn and max gross weight as the retractable gear Piper Saratoga, but has only 200 miles of additional range.  The SR22 has been the best-selling GA aircraft, every single year, since 2003.  For light aircraft that fly at 250mph or less, retractable gear can often be significantly heavier than fixed gear (the Piper PA-32 vs PA-32R represents a 200 pound weight increase) and provide only marginal aerodynamic and therefore range improvements.  Basically, any affordable airframe and power plant combination that is not propelled by very large and heavy WWII era radials, or is multi-engined, or is equipped with a turboprop, is what the wisdom of fixed gear applies to.  You can't legally fly faster than 250 knots below 10,000 feet anyway.  Oddly enough, that slippery SR22 also uses a John Roncz airfoil design.  That should demonstrate just how "tight" the design space is for a 300hp 4-seat to 7-seat aircraft.  The SR22 is "only" about double the cost of an all-Aluminum airframe with only slightly less performance.  You have to get deep into 6-seat to 12-seat turboprop territory before the strength-to-weight ratio of autoclaved CFRP composites provides enough of a weight advantage over Aluminum to truly justify the cost.  In lighter / slower aircraft with fewer seats, the weight of most composite aircraft built with sufficient structural margin for certification generally makes them as heavy as Aluminum.

The fixed gear SR22 has a substantially higher empty weight than the retractable gear PA-32R Saratoga, specifically because the strength margins required to certify a small composite airframe cause it to be every bit as heavy as an Aluminum airframe with similar range and speed.  The only real advantage is the ability to do compound curves using composites, as the Aluminum in very light aircraft is too thin for that.  The SR22's airframe is crazy strong, no doubt about that, but that's because it has to be to pass certification.  Only 80 pounds of the 292 pounds of increased weight over the PA-32R is due to the CAPS ballistic airframe parachute system installed.

The automotive-applicable aspect of all this talk about composite aircraft design is the simple fact that the new Cirrus SR22 is a four-seat flying vehicle with a 300hp gasoline engine happens to have roughly the same empty weight as an all-steel Chrysler 4-seat compact car from the 1960s that still has more interior volume than most modern full size sedans made today, with an all-cast-iron slant 6 engine tuned to make around 300hp at peak output, not continuous as in the case of the IO-550N that powers the SR22, naturally aspirated.  The car in question was restored / modified by a YouTuber / shade tree mechanic who calls himself Uncle Tony, of the Uncle Tony's Garage YouTube channel.

If a shade tree mechanic with hand tools can figure out how to make an all-steel chassis as light as a SR22 yet capable of a similar top speed, then let's start rounding up guys like him to help engineers design a practical / affordable / maintainable all-steel vehicle that doesn't require a monster engine with high fuel consumption.  Uncle Tony made the hood / trunk / frame rails look like the Aluminum ribs of an aircraft wing, for example, to make them light but stiff.  The unibody chassis technology is here to stay, so let's make the most of steel and existing aerospace fabrication methods to come up with light but strong steel structures that allow us to use, in this case, a 225 cubic inch slant six that produces as much output as a 550 cubic inch flat six.

This is clearly achievable using 1960s sheet steel and cast iron construction, so the combination of modern steel foam or honeycomb sandwich panels and compacted graphitic iron engine block / head technology will allow us to arrive near light aircraft empty weights in passenger vehicles, with spritely performance provided by much smaller displacement engines.  The other part of the key to weight reduction is simplicity, which includes manual steering, shifting, windows.  If the car doesn't have electric windows or infinitely variable electronic transmission, then there's no motors to add both weight and cost to the finished product.  If you want an infotainment system, then buy an iPad.

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#57 2021-05-02 06:59:49

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 5,751

Re: Fixing Americas car industry

For kbd512 re #56

SearchTerm:Analysis of materials, energy costs, performance and other factors for automobiles vs aircraft

Comment: Nice to see mention of Uncle Tony !!!

(th)

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