Are electric cars more energy efficient?
I was thinking about electric cars today.
An internal combustion car, burns fuel inside cylinders and produces energy according to Carnot cycle. Say, it makes 28% of energy from the total BTU of fuel that it burns. Compare it with an electric car. A coal electric power station operates at efficiency of 33% (Wikipedia). Then 10% of this is lost in power distribution. More lost in stepping down line voltage to 220 volts. Further, more is lost in a battery charger. Then more is lost in the car battery. Then more heat is lost in motor windings and power semiconductors. This is probably by far less efficient than internal combustion an distribution of gasoline! And how is it going to reduce CO2 emissions, if more CO2 needs to be burned as coal than would come from gasoline? i |
Are electric cars more energy efficient?
On Mon, 25 Jun 2012 22:08:16 -0500, Ignoramus6950
wrote: I was thinking about electric cars today. An internal combustion car, burns fuel inside cylinders and produces energy according to Carnot cycle. Say, it makes 28% of energy from the total BTU of fuel that it burns. Compare it with an electric car. A coal electric power station operates at efficiency of 33% (Wikipedia). Then 10% of this is lost in power distribution. More lost in stepping down line voltage to 220 volts. Further, more is lost in a battery charger. Then more is lost in the car battery. Then more heat is lost in motor windings and power semiconductors. This is probably by far less efficient than internal combustion an distribution of gasoline! And how is it going to reduce CO2 emissions, if more CO2 needs to be burned as coal than would come from gasoline? i The only way it really "saves" anything is with hydro power, solar, wind, or atomic. Possibly Natural gas. |
Are electric cars more energy efficient?
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Are electric cars more energy efficient?
"Ignoramus6950" wrote in message ... I was thinking about electric cars today. An internal combustion car, burns fuel inside cylinders and produces energy according to Carnot cycle. Say, it makes 28% of energy from the total BTU of fuel that it burns. Compare it with an electric car. A coal electric power station operates at efficiency of 33% (Wikipedia). Then 10% of this is lost in power distribution. More lost in stepping down line voltage to 220 volts. Further, more is lost in a battery charger. Then more is lost in the car battery. Then more heat is lost in motor windings and power semiconductors. This is probably by far less efficient than internal combustion an distribution of gasoline! And how is it going to reduce CO2 emissions, if more CO2 needs to be burned as coal than would come from gasoline? As far as cost per mile traveled, there can be no doubt that fully electric automobiles are extremely economical to operate, and except for energy that's lost due to heat and friction, they are 100% efficient all the way from zero clear up to full rated output. The problem is that the combustion engines that have traditionally been used in automobiles are only mildly efficient at best when run at peak output, at conditions other than peak, they are so terribly inefficient that trying to compare them to a coal or natural gas fired electrical generation plant is pretty much an absurd notion. Enter the Atkinson cycle internal combustion engine, and hopefully you'll start to understand the reason why hybrids are able to be so fuel-efficient while also being able to perform reasonably well when you put the pedal down. http://en.wikipedia.org/wiki/Atkinson_cycle "While a modified Otto cycle engine using the Atkinson cycle provides good fuel economy, it is at the expense of a lower power-per-displacement as compared to a traditional four-stroke engine.[3] If demand for more power is intermittent, the power of the engine can be supplemented by an electric motor during times when more power is needed. This forms the basis of an Atkinson cycle-based hybrid electric drivetrain. These electric motors can be used independently of, or in combination with, the Atkinson cycle engine, to provide the most efficient means of producing the desired power. This drive train first entered production in late 1997 in the Japanese-market Toyota Prius." |
Are electric cars more energy efficient?
On Mon, 25 Jun 2012 21:33:24 -0700, PrecisionmachinisT wrote:
"Ignoramus6950" wrote in message ... I was thinking about electric cars today. An internal combustion car, burns fuel inside cylinders and produces energy according to Carnot cycle. Say, it makes 28% of energy from the total BTU of fuel that it burns. Compare it with an electric car. A coal electric power station operates at efficiency of 33% (Wikipedia). Then 10% of this is lost in power distribution. More lost in stepping down line voltage to 220 volts. Further, more is lost in a battery charger. Then more is lost in the car battery. Then more heat is lost in motor windings and power semiconductors. This is probably by far less efficient than internal combustion an distribution of gasoline! And how is it going to reduce CO2 emissions, if more CO2 needs to be burned as coal than would come from gasoline? As far as cost per mile traveled, there can be no doubt that fully electric automobiles are extremely economical to operate, and except for energy that's lost due to heat and friction, they are 100% efficient all the way from zero clear up to full rated output. Nuh uh. Nothing is 100% efficient. If perpetual motion is pie-in-the- sky, 100% efficiency is the pie plate. While I haven't seen power budgets, if an electric car manages to take 80% of the energy that came in on the charging plug and turns it into forward motion, I'd be surprised. -- Tim Wescott Control system and signal processing consulting www.wescottdesign.com |
Are electric cars more energy efficient?
"Tim Wescott" wrote in message ... On Mon, 25 Jun 2012 21:33:24 -0700, PrecisionmachinisT wrote: "Ignoramus6950" wrote in message ... I was thinking about electric cars today. An internal combustion car, burns fuel inside cylinders and produces energy according to Carnot cycle. Say, it makes 28% of energy from the total BTU of fuel that it burns. Compare it with an electric car. A coal electric power station operates at efficiency of 33% (Wikipedia). Then 10% of this is lost in power distribution. More lost in stepping down line voltage to 220 volts. Further, more is lost in a battery charger. Then more is lost in the car battery. Then more heat is lost in motor windings and power semiconductors. This is probably by far less efficient than internal combustion an distribution of gasoline! And how is it going to reduce CO2 emissions, if more CO2 needs to be burned as coal than would come from gasoline? As far as cost per mile traveled, there can be no doubt that fully electric automobiles are extremely economical to operate, and except for energy that's lost due to heat and friction, they are 100% efficient all the way from zero clear up to full rated output. Nuh uh. Nothing is 100% efficient. If perpetual motion is pie-in-the- sky, 100% efficiency is the pie plate. Which is why I mentioned "heat and friction loss"... --learn to read, pal. While I haven't seen power budgets, if an electric car manages to take 80% of the energy that came in on the charging plug and turns it into forward motion, I'd be surprised. The rest of it "evaporates".....same as with a gasoline vehicle... |
Are electric cars more energy efficient?
"Tim Wescott" wrote in message ... While I haven't seen power budgets, if an electric car manages to take 80% of the energy that came in on the charging plug and turns it into forward motion, I'd be surprised. http://avt.inel.gov/pdf/fsev/costs.pdf |
Are electric cars more energy efficient?
On Mon, 25 Jun 2012 22:08:16 -0500, Ignoramus6950
wrote: I was thinking about electric cars today. An internal combustion car, burns fuel inside cylinders and produces energy according to Carnot cycle. Say, it makes 28% of energy from the total BTU of fuel that it burns. Compare it with an electric car. A coal electric power station operates at efficiency of 33% (Wikipedia). Then 10% of this is lost in power distribution. More lost in stepping down line voltage to 220 volts. Further, more is lost in a battery charger. Then more is lost in the car battery. Then more heat is lost in motor windings and power semiconductors. This is probably by far less efficient than internal combustion an distribution of gasoline! I'll address your efficiency figures at a later date. And how is it going to reduce CO2 emissions, if more CO2 needs to be burned as coal than would come from gasoline? If the frackin' tree huggers and our gov't would get out of the way of nuclear energy, it would be more dependable and a helluva lot less polluting than coal fired plants are now. -- Always bear in mind that your own resolution to succeed is more important than any one thing. -- Abraham Lincoln |
Are electric cars more energy efficient?
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Are electric cars more energy efficient?
If the frackin' tree huggers and our gov't would get out of the way of nuclear energy, it would be more dependable and a helluva lot less polluting than coal fired plants are now. things were starting to move, but then the event in Japan shut it down. We're not likely to see ANY new nuclear plants for decades. Karl |
Are electric cars more energy efficient?
"Ignoramus6950" wrote in message ... I was thinking about electric cars today. An internal combustion car, burns fuel inside cylinders and produces energy according to Carnot cycle. Say, it makes 28% of energy from the total BTU of fuel that it burns. Compare it with an electric car. A coal electric power station operates at efficiency of 33% (Wikipedia). i If you put a similarly low powered gas engine in a car you could achieve similar efficiency, but it would be only feeble, without the compensating green status appeal. Such cars don't sell well enough. The people who demand them want to force them on someone else. http://www.autoblog.com/2009/07/31/h...on-from-prius/ My 1978 Accord averaged 36-38 MPG with the interior space of a Saab or BMW. It handled better than my rich buddy's Saab 900 Turbo, too. (but was no match for his BMW 2002) jsw, |
Are electric cars more energy efficient?
In article ,
says... "Tim Wescott" wrote in message ... While I haven't seen power budgets, if an electric car manages to take 80% of the energy that came in on the charging plug and turns it into forward motion, I'd be surprised. http://avt.inel.gov/pdf/fsev/costs.pdf That's dollar cost and has little to do with the actual energy consumed. Remember that much of the cost of a gallon of gasoline is taxes. Those same taxes are not currently applied to electric vehicles, but if they become popular those taxes will be. |
Are electric cars more energy efficient?
"PrecisionmachinisT" wrote in message While I haven't seen power budgets, if an electric car manages to take 80% of the energy that came in on the charging plug and turns it into forward motion, I'd be surprised. http://avt.inel.gov/pdf/fsev/costs.pdf The glaring error there is ignoring the batteries as an operating cost. http://www.plugincars.com/replacing-...ry-122261.html I've tested high-end batteries at Segway and [a medical equipment manufacturer] and seen a small percentage of Lithiums begin to degrade in less than a year. The packs' built-in supervisory computer recorded all charge and discharge cycles, temperature and remaining capacity. The battery maker wouldn't promise more than three years life, regardless of cycle count. What is your experience with the same battery technologies in power tools and laptops? Mine isn't good. I have to employ lab tech tricks on the batteries to keep my Makita drills and 5+ year old laptops running. jsw |
Are electric cars more energy efficient?
"Ignoramus6950" wrote in message ... I was thinking about electric cars today. An internal combustion car, burns fuel inside cylinders and produces energy according to Carnot cycle. Say, it makes 28% of energy from the total BTU of fuel that it burns. Compare it with an electric car. A coal electric power station operates at efficiency of 33% (Wikipedia). Then 10% of this is lost in power distribution. More lost in stepping down line voltage to 220 volts. Further, more is lost in a battery charger. Then more is lost in the car battery. Then more heat is lost in motor windings and power semiconductors. This is probably by far less efficient than internal combustion an distribution of gasoline! And how is it going to reduce CO2 emissions, if more CO2 needs to be burned as coal than would come from gasoline? i You forgot to add for petroleum refining losses. Gas manufacture runs around 85% efficiency. That puts your internal combustion engine closer to 24% efficiency. Paul K. Dickman |
Are electric cars more energy efficient?
Ignoramus6950 wrote: I was thinking about electric cars today. An internal combustion car, burns fuel inside cylinders and produces energy according to Carnot cycle. Say, it makes 28% of energy from the total BTU of fuel that it burns. Compare it with an electric car. A coal electric power station operates at efficiency of 33% (Wikipedia). Then 10% of this is lost in power distribution. More lost in stepping down line voltage to 220 volts. Further, more is lost in a battery charger. Then more is lost in the car battery. Then more heat is lost in motor windings and power semiconductors. This is probably by far less efficient than internal combustion an distribution of gasoline! And how is it going to reduce CO2 emissions, if more CO2 needs to be burned as coal than would come from gasoline? i The source of the electricity used for charging has the greatest impact on the true efficiency and emissions as everyone else noted. What they forgot to note is that EVs do not consume any energy during stops or downhill grades, and recapture some energy during braking, both of which can further improve efficiency to a variable amount based on terrain and usage. |
Are electric cars more energy efficient?
"Pete C." wrote in message .com... The source of the electricity used for charging has the greatest impact on the true efficiency and emissions as everyone else noted. What they forgot to note is that EVs do not consume any energy during stops or downhill grades, and recapture some energy during braking, both of which can further improve efficiency to a variable amount based on terrain and usage. Planning the route and timing of your shopping trips does that too, with any vehicle. jsw |
Are electric cars more energy efficient?
"Paul K. Dickman" wrote in message ... "Ignoramus6950" wrote in message ... I was thinking about electric cars today. An internal combustion car, burns fuel inside cylinders and produces energy according to Carnot cycle. Say, it makes 28% of energy from the total BTU of fuel that it burns. Compare it with an electric car. A coal electric power station operates at efficiency of 33% (Wikipedia). Then 10% of this is lost in power distribution. More lost in stepping down line voltage to 220 volts. Further, more is lost in a battery charger. Then more is lost in the car battery. Then more heat is lost in motor windings and power semiconductors. This is probably by far less efficient than internal combustion an distribution of gasoline! And how is it going to reduce CO2 emissions, if more CO2 needs to be burned as coal than would come from gasoline? i You forgot to add for petroleum refining losses. Gas manufacture runs around 85% efficiency. That puts your internal combustion engine closer to 24% efficiency. Paul K. Dickman Also, your transmission losses are high. According to the EIA electric transmission losses are 7% average nationwide (5.5% here in IL) and are based on total production + imports - direct use -watts sold. So it would include losses at stepdown to 220. Paul K. Dickman |
Are electric cars more energy efficient?
"Paul K. Dickman" wrote in message
... According to the EIA electric transmission losses are 7% average nationwide (5.5% here in IL) and are based on total production + imports - direct use -watts sold. So it would include losses at stepdown to 220. Paul K. Dickman This analysis neglects the differences between the qualities of energy sources. Coal won't fuel a car directly, it's only good for making steam . Petroleum is more versatile. Electricity is the highest, most valuable form which can do almost anything except be stored cheaply in bulk.. jsw |
Are electric cars more energy efficient?
"PrecisionmachinisT" wrote in message And before anyone starts suggests that government ought to take over, using taxpayer dollars, you need to realize that someone's taxes would need to go up, and that government-control of energy production is a textbook example of socialism. The government has owned and controlled energy production since 1933: http://en.wikipedia.org/wiki/Tennessee_Valley_Authority "The Kentucky Sierra Club called the [2008 Kingston] disaster the "worst environmental disaster since Chernobyl"." "The disaster continues to poison lakes and stream as well as potentially the drinking water of millions." Who knew? jsw |
Are electric cars more energy efficient?
On 6/26/2012 6:08, Ignoramus6950 wrote:
I was thinking about electric cars today. An internal combustion car, burns fuel inside cylinders and produces energy according to Carnot cycle. Say, it makes 28% of energy from the total BTU of fuel that it burns. Compare it with an electric car. A coal electric power station operates at efficiency of 33% (Wikipedia). Then 10% of this is lost in power distribution. More lost in stepping down line voltage to 220 volts. Further, more is lost in a battery charger. Then more is lost in the car battery. Then more heat is lost in motor windings and power semiconductors. This is probably by far less efficient than internal combustion an distribution of gasoline! And how is it going to reduce CO2 emissions, if more CO2 needs to be burned as coal than would come from gasoline? That's simple. Just like any truly green electricity without CO2 emissions. Make the electricity with nuclear power. However, in the cold or hot climate (most places:), one of the big problems with electric cars is AIR CONDITIONING, cooling or heating. In a normal gasoline powered car, there is extra heat to use for heating the car (here in winter at -20C). In the electric car, the extra heat has to come from electricity in battery, and we are talking about several kW.. Electric cars are cold cars in winter as the battery just simply can't handle the heating.. Also, you have to use power to cool it in summer, but that is less of a problem (less delta-T). Perhaps better heat insulation will solve this. The second big problem is that it costs 10000-20000 usd per 5 years for battery replacement.. That makes a LOT for the USD/km cost.. Perhaps better battery technology will solve this. The third big problem is TAXES. Nowadays here in Finland the gasoline costs about 1.7 euro/litre (0.70euro/litre for gasoline and 1.00 euro/litre government tax). If the electric cars come popular, there will definitely be a tax on "electric car electricity".. Perhaps put a kWh counter in each electric car and then pay X.XX USD/kWh electric car electricity tax.. Nothing will solve THIS. Here the reasonable way to go at the moment is with CNG, compressed natural gas. Conversion of old car is about 2500euro. Cost of CNG driving is HALF the cost of gasoline driving, for fuel cost per km. However, the big threat is that government will also put a heavy tax on CNG (like on gasoline), so people are afraid to convert their cars. It takes about 2 years payback time for the conversion. Again, nothing will solve the TAX problem, especially poor predictability on changes of taxes. IMHO. |
Are electric cars more energy efficient?
"Jim Wilkins" wrote in message ... "Paul K. Dickman" wrote in message ... According to the EIA electric transmission losses are 7% average nationwide (5.5% here in IL) and are based on total production + imports - direct use -watts sold. So it would include losses at stepdown to 220. Paul K. Dickman This analysis neglects the differences between the qualities of energy sources. Coal won't fuel a car directly, it's only good for making steam . Petroleum is more versatile. Electricity is the highest, most valuable form which can do almost anything except be stored cheaply in bulk.. jsw I'm not sure what you are referring to. To be clear, my point was that Iggy's original premise was flawed. He assumed no production or distribution losses on petroleum and inflated those losses on electricity. In terms of btus dug from the ground and delivered to the transmission, it is probably a wash. 28% carnot efficiency * 85% production efficiency = 23.8% of the btu dug hit the transmission 33% production efficiency * 93% transmission efficiency = 30.69% for electricity delivered. If the charging and motor losses are 22.45% than it is dead even. As to Iggy's question, "And how is it going to reduce CO2 emissions, if more CO2 needs to be burned as coal than would come from gasoline?" Even if the EV is less efficient than gas engines, not all electricity comes from hydrocarbons but all gasoline comes from hydrocarbons. If the difference in efficiency is less than the percentage of electricity produced from hydro/nuke/solar/wind then it will result in a net reduction of CO2. All that aside, I drive a 12yo pickup. But speaking as a person who owns a hundred different hammers, I say "Diversity is always a good thing and should be encouraged". There's more than one way to skin a cat. That doesn't seem important now, but it's gonna be real handy when we run out of squirrels to eat. Paul K. Dickman |
Are electric cars more energy efficient?
"Jim Wilkins" wrote in message ... "PrecisionmachinisT" wrote in message And before anyone starts suggests that government ought to take over, using taxpayer dollars, you need to realize that someone's taxes would need to go up, and that government-control of energy production is a textbook example of socialism. The government has owned and controlled energy production since 1933: http://en.wikipedia.org/wiki/Tennessee_Valley_Authority "The Kentucky Sierra Club called the [2008 Kingston] disaster the "worst environmental disaster since Chernobyl"." "The disaster continues to poison lakes and stream as well as potentially the drinking water of millions." Who knew? Still, it goes a long ways towards demonstrating that certain projects having the potential of providing huge benefits for all of society are oftentimes beyond the scope of private enterprize alone, the up-front costs being prohibitive. |
Are electric cars more energy efficient?
"J. Clarke" wrote in message in.local... In article , says... "Tim Wescott" wrote in message ... While I haven't seen power budgets, if an electric car manages to take 80% of the energy that came in on the charging plug and turns it into forward motion, I'd be surprised. http://avt.inel.gov/pdf/fsev/costs.pdf That's dollar cost and has little to do with the actual energy consumed. Pretty sure Iggy was primarily looking at the situation from an economic standpoint, specifically, the out-of pocket cost per mile traveled. And besides, you failed to come up with anything that would quantify a diference in the total amount of energy that's actually consumed one way or the other. Remember that much of the cost of a gallon of gasoline is taxes. An equally valid argument could be made that the cost of gasoline would be much higher, were it not subsidized.. http://news.nationalgeographic.com/n...09_600x450.jpg Those same taxes are not currently applied to electric vehicles, but if they become popular those taxes will be. Which would be perfectly fine by me.... |
Are electric cars more energy efficient?
"Jim Wilkins" wrote in message ... "PrecisionmachinisT" wrote in message While I haven't seen power budgets, if an electric car manages to take 80% of the energy that came in on the charging plug and turns it into forward motion, I'd be surprised. http://avt.inel.gov/pdf/fsev/costs.pdf The glaring error there is ignoring the batteries as an operating cost. http://www.plugincars.com/replacing-...ry-122261.html Eventual failure and the subsequent replacement of engines, axles, transmissions and so forth is an "operating cost" with fossil fuel vehicles as well. I've tested high-end batteries at Segway and [a medical equipment manufacturer] and seen a small percentage of Lithiums begin to degrade in less than a year. The packs' built-in supervisory computer recorded all charge and discharge cycles, temperature and remaining capacity. The battery maker wouldn't promise more than three years life, regardless of cycle count. As an aside, if recall correctly, probably the biggest problem with batteries is that US lithium extraction is seriously underdeveloped at the moment. What is your experience with the same battery technologies in power tools and laptops? For reasons completely apart from battery performance, typically I use an extension cord and I also have absolutely no desire whatsoever to own a laptop. That said, it's pretty hard to argue that overall, battery performance hasn't improved quite a bit over the last decade or so Mine isn't good. I have to employ lab tech tricks on the batteries to keep my Makita drills and 5+ year old laptops running. Pretty sure it was someplace on a wiki page where it was mentioned that a decade or so ago, there was quite a bit of fear that battery life might possibly turn out to be a HUGE problem but that what actuallly transpired is that in most cases, battery life has greatly exceeded initial engineering expectations. Anyways, here's an article probably that lays out the situation fairly accurately : http://www.greencarreports.com/news/...s-battery-dies |
Are electric cars more energy efficient?
On Tue, 26 Jun 2012 07:42:33 -0500, Paul K. Dickman wrote:
(...) You forgot to add for petroleum refining losses. Gas manufacture runs around 85% efficiency. That puts your internal combustion engine closer to 24% efficiency. Paul K. Dickman There's that 300 - million - year delay in turning biomass into oil, too. If time is money, that is a hell of a toll. --Winston |
Are electric cars more energy efficient?
"PrecisionmachinisT" wrote in message "Jim Wilkins" wrote in message ... The government has owned and controlled energy production since 1933: http://en.wikipedia.org/wiki/Tennessee_Valley_Authority -Still, it goes a long ways towards demonstrating that certain -projects having the potential of providing huge benefits for all -of society are oftentimes beyond the scope of private enterprize -alone, the up-front costs being prohibitive. We swing back and forth in an ad-hoc manner on public vs private utility ownership, often after the private ones succumb to greed or the public ones to incompetence or corruption. Both types need the carrot plus the stick. http://en.wikipedia.org/wiki/Federal_Reserve_Bank http://en.wikipedia.org/wiki/United_...Postal_Service MITRE where I used to work was founded as a private corporation whose research was almost all in the public (=military) interest. Engineering the DEW line of radars across Canada had required a broader range of radar + computer + communications expertise than any one company possessed. At first MIT got the contract, spinning off Lincoln Labs, but the workload was too great for professors part-time. MITRE was the next attempt, on the same model as the RAND Corporation and Sandia Labs, among many others. http://en.wikipedia.org/wiki/RAND_Corporation http://en.wikipedia.org/wiki/Sandia_...l_Laboratories Not being a direct government employee has a lot of benefits such as freedom to work on a wider range of projects, if you value adventure over stability. Still it was a strange shadowy world. jsw |
Are electric cars more energy efficient?
Ignoramus6950 wrote:
I was thinking about electric cars today. An internal combustion car, burns fuel inside cylinders and produces energy according to Carnot cycle. Say, it makes 28% of energy from the total BTU of fuel that it burns. Not even close. A good Otto-cycle engine gets maybe 13% efficiency at near wide-open throttle. At typical mid-throttle operation, it is much worse, maybe 5-8%. A semi-Atkinson cycle engine like in my Honda Civic Hybrid does better at mid-throttle, as does a Diesel by eliminating pumping losses. So, a standard gas engine is a lot worse than you might imagine. Most of the electrical gear is WAY more efficient than that, hence small heat sinks and minimal cooling system are needed. No, the losses in the electrical system are small compared to the incredibly poor efficiency of the typical gas engine. Any time you have the gas pedal less than floored, you are practically driving with the brakes on! Read up on "pumping loss" if you don't believe me. Then, look at the VAST amount of heat going out the tailpipe, and the significant amount of heat going out the radiator. Just being able to drive without these massive heat losses gives some idea of the efficiency of electric vehicles. Compare the KWH energy loaded into the batteries of a typical EV against the BTU content of a tank of gas, you won't believe the numbers! Jon |
Are electric cars more energy efficient?
Jim Wilkins wrote:
What is your experience with the same battery technologies in power tools and laptops? Mine isn't good. I have to employ lab tech tricks on the batteries to keep my Makita drills and 5+ year old laptops running. Yup, this is Honda's dirty little secret. It looks like they will be replacing a majority of the battery packs in the Honda Civic Hybrid over the course of their 80K mile warranty in the general US, and probably almost all in California with the 100K warranty. Lots of people are troubled with battery degradation and outright failure. One nice feature is the car can still be driven with a failed battery. The HCH has no cell balancer system, which I think is a big mistake. Not sure if the Prius has this, but they seem to have a lot better luck with their battery system. In the HCH, they are running 100A through Ni-MH D-cells! Jon |
Are electric cars more energy efficient?
On Tue, 26 Jun 2012 14:06:01 -0500, "Paul K. Dickman"
wrote: speaking as a person who owns a hundred different hammers, I say "Diversity is always a good thing and should be encouraged". I'm considering buying a Chevy Volt. I know it's a long payout but I can afford it and I want to support new tech. So far one salesman! and two friends have tried to talk me out of the idea. I know more about the car and the cost-benefit than all three put together but I may as well fart into the wind as expect their support. Their collective opinion seems to be that what I'm doing is good for everyone except myself and I think that subconsciously they oppose that kind of diversity. The irony is that none of them would try to talk me out of a gas guzzler or a new toy because all three have their share of those. By the way if anybody's interested in reading the Volt shop manual it's online here http://www.autocats.net/manual/chevr...tart_Volt.html |
Are electric cars more energy efficient?
Jon Elson wrote:
Ignoramus6950 wrote: I was thinking about electric cars today. An internal combustion car, burns fuel inside cylinders and produces energy according to Carnot cycle. Say, it makes 28% of energy from the total BTU of fuel that it burns. Not even close. A good Otto-cycle engine gets maybe 13% efficiency at near wide-open throttle. At typical mid-throttle operation, it is much worse, maybe 5-8%. A semi-Atkinson cycle engine like in my Honda Civic Hybrid does better at mid-throttle, as does a Diesel by eliminating pumping losses. Modern gasoline engines have a maximum thermal efficiency of about 25% to 30% when used to power a car. In other words, even when the engine is operating at its point of maximum thermal efficiency, of the total heat energy released by the gasoline consumed, about 70-75% is rejected as heat without being turned into useful work, i.e. turning the crankshaft. Approximately half of this rejected heat is carried away by the exhaust gases, and half passes through the cylinder walls or cylinder head into the engine cooling system, and is passed to the atmosphere via the coolant system radiator[1]. Some of the work generated is also lost as friction, noise, air turbulence, and work used to turn engine equipment and appliances such as water and oil pumps and the electrical generator, and only about 25-30% of the energy released by the fuel consumed is available to move the vehicle. At idle, the thermal efficiency is zero since no usable work is being drawn from the engine. At low speeds gasoline engines suffer efficiency losses at small throttle openings from the high turbulence and frictional (head) loss when the incoming air must fight its way around the nearly closed throttle; diesel engines do not suffer this loss because the incoming air is not throttled. At high speeds, efficiency in both types of engine is reduced by pumping and mechanical frictional losses, and the shorter time period within which combustion has to take place. Engine efficiency peaks in most applications at around 75% of rated engine power, which is also the range of greatest engine torque (e.g. in the 2007 Ford Focus, maximum torque of 133 foot-pounds (180 Nm) is obtained at 4,500 RPM, and maximum engine power of 136 brake horsepower (101 kW) is obtained at 6,000 RPM). At all other combinations of engine speed and torque, the thermal efficiency is less than this maximum. In the past 3-4 years, GDI (Gasoline Direct Injection) increased the efficiency of the engines equipped with this fueling system up to 35%. Currently the technology is available in a wide variety of vehicles ranging from affordable cars from Mazda, Ford and Chevrolet to more expensive cars from BMW, Mercedes-Benz, VAG. http://www.fueleconomy.gov/feg/atv.shtml Only about 14%–26% of the energy from the fuel you put in your tank gets used to move your car down the road, depending on the drive cycle. The rest of the energy is lost to engine and driveline inefficiencies or used to power accessories. Therefore, the potential to improve fuel efficiency with advanced technologies is enormous. Improving IC Engine Efficiency Today’s efficiency situation: FUEL 100% PUSHING THE PISTONS 35% OVERCOMING ENGINE FRICTION AND PUMPING THE AIR AND FUEL (typical US driving condition) 20% So, a standard gas engine is a lot worse than you might imagine. Most of the electrical gear is WAY more efficient than that, hence small heat sinks and minimal cooling system are needed. No, the losses in the electrical system are small compared to the incredibly poor efficiency of the typical gas engine. Any time you have the gas pedal less than floored, you are practically driving with the brakes on! Read up on "pumping loss" if you don't believe me. Then, look at the VAST amount of heat going out the tailpipe, and the significant amount of heat going out the radiator. Just being able to drive without these massive heat losses gives some idea of the efficiency of electric vehicles. Compare the KWH energy loaded into the batteries of a typical EV against the BTU content of a tank of gas, you won't believe the numbers! Jon -- Steve W. |
Are electric cars more energy efficient?
If you're going to correct someone else, try to get your facts right.
http://www.differentsourcesofelectricity.com/ Sources of electricity in the United States 49.8% of electricity in the US is generated by burning coal 19.9% from nuclear power, 17.9% from natural gas 6.5% from hydroelectric, 3% from burning petroleum a paltry 2.3% from other renewable energy sources such as wind power , solar energy , geothermal power, and biomass. Renewable energy accounts for about 8% of all electricity generated. (Source: Energy Information Administration) A list of the different types of power plants Information on renewable energy and renewable sources of electricity Breakdown of how electricity is generated in the US Christopher A. Young Learn more about Jesus www.lds.org .. "Robert Roland" wrote in message ... No, it does not. There are essentially two sources of electric power on the planet: Hydroelectric and coal. There are others, but they are very small. -- RoRo |
Are electric cars more energy efficient?
I doubt it. Diesel and gasoline power cars do pretty well. Electric cars
need storage batteries, which are notably ineffecient. Christopher A. Young Learn more about Jesus www.lds.org .. |
Are electric cars more energy efficient?
Jim Wilkins wrote:
My 1978 Accord averaged 36-38 MPG with the interior space of a Saab or BMW. It handled better than my rich buddy's Saab 900 Turbo, too. (but was no match for his BMW 2002) Just came back from the CNC Workshop in Ann Arbor, to St. Louis, approx. 525 miles. I did 46 MPG up and back, running at about 70 MPH most of the way. Around town I can get 56 MPG without the air conditioning, but now that it is hotter, about 52 MPG with the A/C. This is a Honda Civic Hybrid. Jon |
Are electric cars more energy efficient?
Pete C. wrote:
The source of the electricity used for charging has the greatest impact on the true efficiency and emissions as everyone else noted. What they forgot to note is that EVs do not consume any energy during stops or downhill grades, and recapture some energy during braking, both of which can further improve efficiency to a variable amount based on terrain and usage. My Honda hybrid does the same. As soon as you take your foot off the gas, the fuel is cut off and the intake valves are closed, allowing the engine to freewheel with low losses. As you slow for a stop, at 9 MPH the clutch drops out and the engine stops completely. When you take your foot off the brake, the engine is spun up by the assist motor and the valves are engaged. The motor assists acceleration to cover for the woeful power output of the semi-Atkinson cycle engine. The assist motor also absorbs energy to charge the battery during downhill grades and average braking. So, on Honda Hybrids, the brakes usually last the life of the car. Jon |
Are electric cars more energy efficient?
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Are electric cars more energy efficient?
If the frackin' tree huggers and our gov't would get out of the way of nuclear energy, it would be more dependable and a helluva lot less polluting than coal fired plants are now. things were starting to move, but then the event in Japan shut it down. We're not likely to see ANY new nuclear plants for decades. Why don't we hear more about thorium reactors? |
Are electric cars more energy efficient?
"Jon Elson" wrote in message
... Ignoramus6950 wrote: ... An internal combustion car, burns fuel inside cylinders and produces energy according to Carnot cycle. Say, it makes 28% of energy from the total BTU of fuel that it burns. Not even close. A good Otto-cycle engine gets maybe 13% efficiency at near wide-open throttle. At typical mid-throttle operation, it is much worse, maybe 5-8%. A semi-Atkinson cycle engine like in my Honda Civic Hybrid does better at mid-throttle, as does a Diesel by eliminating pumping losses. Jon My 1949 Aircraft Powerplant Handbook puts the typical engine output power at 29.5% of the energy in the fuel at cruise, 60% of rated power. http://en.wikipedia.org/wiki/Brake_s...el_consumption The R-3350 (B-29, DC-7) was better at 33.7%, close to the top of the range for the most efficient gasoline car engines. It used an exhaust power recovery turbine system that's much too complex and expensive for an economy car. http://en.wikipedia.org/wiki/Turbo-compound_engine jsw |
Are electric cars more energy efficient?
On 6/25/2012 11:08 PM, Ignoramus6950 wrote:
I was thinking about electric cars today. An internal combustion car, burns fuel inside cylinders and produces energy according to Carnot cycle. Say, it makes 28% of energy from the total BTU of fuel that it burns. Compare it with an electric car. A coal electric power station operates at efficiency of 33% (Wikipedia). Then 10% of this is lost in power distribution. More lost in stepping down line voltage to 220 volts. Further, more is lost in a battery charger. Then more is lost in the car battery. Then more heat is lost in motor windings and power semiconductors. This is probably by far less efficient than internal combustion an distribution of gasoline! And how is it going to reduce CO2 emissions, if more CO2 needs to be burned as coal than would come from gasoline? i Ya'but does it make one FEEL good? |
Are electric cars more energy efficient?
On 6/26/2012 12:55 AM, Larry Jaques wrote:
On Mon, 25 Jun 2012 22:08:16 -0500, Ignoramus6950 wrote: I was thinking about electric cars today. An internal combustion car, burns fuel inside cylinders and produces energy according to Carnot cycle. Say, it makes 28% of energy from the total BTU of fuel that it burns. Compare it with an electric car. A coal electric power station operates at efficiency of 33% (Wikipedia). Then 10% of this is lost in power distribution. More lost in stepping down line voltage to 220 volts. Further, more is lost in a battery charger. Then more is lost in the car battery. Then more heat is lost in motor windings and power semiconductors. This is probably by far less efficient than internal combustion an distribution of gasoline! I'll address your efficiency figures at a later date. And how is it going to reduce CO2 emissions, if more CO2 needs to be burned as coal than would come from gasoline? If the frackin' tree huggers and our gov't would get out of the way of nuclear energy, it would be more dependable and a helluva lot less polluting than coal fired plants are now. -- Always bear in mind that your own resolution to succeed is more important than any one thing. -- Abraham Lincoln Imagine where the nuclear industry would be now if not for "them". Fusion would undoubtedly be closer to reality. Gee, who doesn't want almost free, clean energy? Who would lose their power base? |
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