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Author Topic: Is it possible to build a full size car that gets 200 miles per gallon?  (Read 26122 times)

Offline Drifty

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Re: It's possible to build a full size car that gets 200 mpg
« Reply #25 on: 09/01/2015 20:07:24 »
Quote
  There's not necessarily any problem in theory about running a car on petrol vapours. It's just that you can't make a 200mpg car that way- not one that drives and looks like an ordinary car. 

After having watched this video...

200+ MPG Gasoline Vaporizer Project Original Design (Driving On Only Gasoline Vapor)

...I think the idea is well worth pursuing.  The performance of the car in the above video doesn't doesn't look that different from an ordinary car.  Couldn't some engineers make the necessary improvements to get it up to par?
 

Offline alancalverd

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Re: It's possible to build a full size car that gets 200 mpg
« Reply #26 on: 10/01/2015 00:07:41 »
A quick poke in the eye for "electric is green" believers.

I've just looked at the manufacturers' CO2 per km figures for the G-whizz (2 seat all-electric, 50 mph, 48 mile range) and Citroen Cactus (4 seat diesel, 90 mph, 500 mile range). The "all electric" runs at 62 g/km (emitted at the power station), the Cactus at 82. No real contest, especially on a bumpy road.
 

Offline wolfekeeper

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Re: It's possible to build a full size car that gets 200 mpg
« Reply #27 on: 10/01/2015 01:21:40 »
That's a diesel though, and they're horribly polluting as France is finding out; diesel kills people, heart disease is the least of it. 29000 people per year: http://www.telegraph.co.uk/motoring/green-motoring/10190942/Why-is-killer-diesel-still-poisoning-our-air.html

And note the 62g/km assumes a fossil fuelled power station, if you use wind power or solar or nuclear, it's not far from 0g/km.

They're still pretty expensive but electric cars are getting cheaper and more practical all the time as the production ramps up; they're likely to be fully practical in a couple of years or so.
 

Offline alancalverd

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Re: It's possible to build a full size car that gets 200 mpg
« Reply #28 on: 10/01/2015 08:02:32 »
That's a diesel though, and they're horribly polluting as France is finding out; diesel kills people, heart disease is the least of it. 29000 people per year

A very interesting statistic.

Quote
CVD is also one of the main causes of death in people under 75 in the UK. 26 per cent of premature deaths in men and 18 per cent of premature deaths in women were from CVD in 2011. In 2011 over 42,000 people under 75 died from CVD.

So diesel fumes attack more men than women? Or have we forgotten something, say, for instance,  smoking.

There's little point in analysing the stats for over-75's who will have received most of their exposure to pollutants in the bad old days of domestic coal burning. But the rapid rise in diesel car use, from almost zero 20 years ago to 30% today, should correlate nicely with the under-75 stats if the opening statement is true. Does it?

As for wind or solar power, if you covered the entire British Isles with windmills or solar panels, you wouldn't generate enough electricity to run a million cars, never mind the 20 million we have now. 
« Last Edit: 10/01/2015 14:18:19 by alancalverd »
 

Offline wolfekeeper

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Re: It's possible to build a full size car that gets 200 mpg
« Reply #29 on: 10/01/2015 14:16:48 »
Air pollution is produced from a wide variety of sources, coal, cooking, diesel, petrol and they're all going to be varying over time, particularly coal which is being phased out.

It would probably be difficult to disentangle one variable like that from the mix.

Paris is a particularly bad case, they switched to diesel vehicles, but diesel produces 4 times the Nox emissions compared to petrol, so they're going to ban diesel vehicles in Paris by 2020:

http://www.newscientist.com/article/dn26678-paris-says-non-to-diesel-in-antipollution-push.html#.VLFCL8kl8hk
« Last Edit: 10/01/2015 15:18:45 by wolfekeeper »
 

Offline Drifty

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Re: It's possible to build a full size car that gets 200 mpg
« Reply #30 on: 28/02/2015 14:28:21 »
Start watching this video at the 2:00 time mark.

Diesels, Gaswagons & Zyklon-B Part 3 of 6


If a gas engine can run on wood smoke, its running on gas fumes doesn't seem that implausible.
 

Offline alancalverd

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Re: It's possible to build a full size car that gets 200 mpg
« Reply #31 on: 28/02/2015 15:24:53 »
Most internal combustion engines run on gas, either vaporised hydrocarbons or pure hydrogen. The finer the spray of injected diesel fuel, i.e. the closer it is to a gas, the sharper the combustion.

"Wood smoke" is mostly fine carbon and hydrocarbons so potentially weakly combustible, but "producer gas" (principally carbon monoxide) and "water gas" (carbon dioxide and hydrogen), made from coal, charcoal and wood,  formed the basis of "town gas" until the 1960s and many UK buses and taxis carried gas bags during WWII.   
 

Offline wolfekeeper

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Re: It's possible to build a full size car that gets 200 mpg
« Reply #32 on: 28/02/2015 15:27:31 »
As for wind or solar power, if you covered the entire British Isles with windmills or solar panels, you wouldn't generate enough electricity to run a million cars, never mind the 20 million we have now. 
This is actually incorrect.

If you go here:

http://www.withouthotair.com/c4/page_33.shtml

you find that they work it out as 8kW per person, just for wind. That's enormously more than the amount you need for electric cars.

However, they then use the faulty argument that you couldn't cover the whole island with wind mills, but you pretty much could, 10% is a very conservative number, and there's also off-shore wind as well, where you definitely can.

edit fwiw: Average mileage in the UK is currently about 8000 miles per year. Electric cars get about 250 Wh to the mile. So that's 2000kWh per year, which would be 10 days at 8kW for the owner (and a lot of people don't have cars).

edit2: MacKay uses 40kWh/d for an electric car. This is far, far too high. He got it from the energy in the petrol to go the average distance, but electric cars are about 5 times more efficient. The average mileage is about 20 miles per day, but that's only about 5 kWh.
« Last Edit: 28/02/2015 16:44:32 by wolfekeeper »
 

Offline Don_1

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Re: It's possible to build a full size car that gets 200 mpg
« Reply #33 on: 03/03/2015 09:36:59 »
This is the Volkswagen XL1. I first encountered it while working on the Queens Coronation Festival a couple of years ago.


It is claimed to be capable of 261 miles per gallon. See this report
 

Offline alancalverd

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Re: It's possible to build a full size car that gets 200 mpg
« Reply #34 on: 03/03/2015 12:17:18 »
As for wind or solar power, if you covered the entire British Isles with windmills or solar panels, you wouldn't generate enough electricity to run a million cars, never mind the 20 million we have now. 
This is actually incorrect.

If you go here:

http://www.withouthotair.com/c4/page_33.shtml

you find that they work it out as 8kW per person, just for wind. That's enormously more than the amount you need for electric cars.

Cars are not the problem if you average all the consumption. Present UK total energy usage is about 8 kW per capita averaged over a year. During peak traffic times we have at least 10,000,000 vehicles on the road, each running at around 20 kW, i.e. something close to 4 kW per capita in addition to all the background domestic and industrial use.
 

Offline wolfekeeper

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Re: It's possible to build a full size car that gets 200 mpg
« Reply #35 on: 03/03/2015 23:31:24 »
Electric cars use about a quarter of the energy to do the same thing as fossil cars. Mr. Carnot says that no heat engine can compete with a battery and electric motor for efficiency; and using wind turbines (and some PV) for powering them is a really excellent combo.
 

Offline alancalverd

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Re: It's possible to build a full size car that gets 200 mpg
« Reply #36 on: 03/03/2015 23:51:57 »
Amazing! Different laws of physics apply to electric cars! Despite being heavier than their fossil-fuelled equivalents, they use less energy to move! If this were true, we'd all be flying electric aeroplanes. After all, the electric motor predates the gasoline engine by about 40 years.

The power rating of an internal combustion engine is the power it delivers, not the theoretical heat of combustion of the fuel. So a 10 kW engine, whether electric or gasoline, delivers 10 kW.
 

Offline wolfekeeper

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Re: It's possible to build a full size car that gets 200 mpg
« Reply #37 on: 04/03/2015 02:22:26 »
Yes, they absolutely are hugely more efficient, and there's no new physics.

It's easy to forget just how awfully inefficient internal combustion engines are in this context.

To make a petrol car produce 10kW, you have burn about 50kW-worth of petrol; the 10kW is useful mechanical motion, but the other 40kW is waste heat that comes out of the exhaust pipe and radiator.

Electric cars are more like 80% efficient; batteries and electric motors are very efficient. Does this really surprise you?

Rolling friction isn't that big anyway, the extra weight mostly slows acceleration a bit, but a lot of the energy is recouped via regenerative braking; so the penalty is much less than you'd think.
« Last Edit: 04/03/2015 02:26:15 by wolfekeeper »
 

Offline alancalverd

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Re: It's possible to build a full size car that gets 200 mpg
« Reply #38 on: 04/03/2015 13:20:57 »
But if you are going to keep up with traffic, you need to deliver 20 kW to the wheels, regardless of the prime mover.

It all depends on what you consider to be the prime mover. The transmission of a conventional car is about 80% efficient, so the question is whether you generate your 20 kW on the spot by burning 40 kW of diesel, or at some remote location by burning 50 kW of coal to charge your battery. The advantage of burning it on the spot is that you can use the "waste" heat to keep the cabin warm and defrost the windows (up to 10 kW is handy in a big saloon).

My ideal would be a constant-speed gas turbine driving a polyphase electronic transmission - a 21st century evolution of the diesel-electric locomotive, with a much better power/weight ratio than even a piston engine.
 

Offline wolfekeeper

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Re: It's possible to build a full size car that gets 200 mpg
« Reply #39 on: 04/03/2015 15:07:58 »
Yes, you need 10-20kW to keep up with traffic, but to do that, an electric car only needs ~13-25kW of electricity.  A diesel car needs 20-40kW of energy or more.

I consider wind power to be a prime mover.

The claim you made was that it wasn't possible to power all cars off wind, but because wind directly produces electricity and because electric cars are, even compared to diesel cars, super-efficient, then it can do this, and when you do this, the net energy requirement of the UK goes down.

The energy to heat the car and its windows is actually pretty small, we're talking about (say) a kilowatt, peak, and the latest cars use air source heat pumps to reduce that by a factor of up to 3.

 

Offline alancalverd

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Re: It's possible to build a full size car that gets 200 mpg
« Reply #40 on: 04/03/2015 16:03:49 »
As I write, the wind is not blowing, and probably won't get above 5 mph peak, 1 mph average, for the next two days. So I need a car with, say, sufficient battery capacity to last 5 days at 300 miles/day.

The Tesla seems the best electric car for my purposes - my weekday mileage is often 300/day, mostly motorway.

No chance of 5-day capacity, so I'll settle for 1 day. Recharging time is 13 hours, assuming I can find a 7.4 kW socket. So instead of using the car to help me do my job, I have to plan my life around the car and accept the fact that there may be many days when I can't use it. Then when the wind does blow, we will need another 15 GW (25%) of installed generating and distribution capacity to charge up everyone's vehicle. I don't think this makes economic sense.
 

Offline wolfekeeper

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Re: It's possible to build a full size car that gets 200 mpg
« Reply #41 on: 04/03/2015 16:20:33 »
Really? No wind? What country are you living in? Because it's not the UK:

http://gridwatch.templar.co.uk/

2.71 GW right now, and it's been well over 5 GW all night.

I'm not designing a car for you; and note that you perfectly well can do 300 miles in a Nissan leaf, you would need to do two fast charges; they take about 20 minutes each at a fast charger, which are found on motorways. A 300 mile journey is going to take hours anyway, so big deal, stop and have a sandwich!

You also have bizarre ideas how the electrical grid works. Does it ever occur to you that having wind forecasts that predicts peaks and troughs of wind power allows the fleet of cars to even the grid out very well? So far from the cars being a drain on the grid, they help the grid work more efficiently.
 

Offline alancalverd

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Re: It's possible to build a full size car that gets 200 mpg
« Reply #42 on: 04/03/2015 18:08:06 »
That turns my car from a convenient form of transport for me, into a social duty to keep down the cost of electricity.

Just looked at the Leaf specification. Motorway driving at 55 mph will give me about 75 miles between charges if I use the heater or aircon, so my 300 mile day will take 5.5 hours of driving and require 4 charges at 20 minutes if I can plan the journey to suit the availability of charging points. That's about 7 hours' driving. No mention of cruising range at 70 mph.

With a full tank, my diesel Mondeo can do it twice at 70 mph without stopping to fill up (5 minutes) in just 8.5 hours.
 

Offline wolfekeeper

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Re: It's possible to build a full size car that gets 200 mpg
« Reply #43 on: 04/03/2015 19:14:01 »
The leaf is a better car, it's quieter, easier to drive, mostly faster, more economical and cheaper to run. And it's already fully charged each day when you get into it, so it's only 3 charges at most. And you don't necessarily have the aircon or heater on; and the car is already at the right temperature when you get in because you can set it to do that.

And presumably you don't do 300 miles every day or every week. If you did you would be better off with a plug-in hybrid.
 

Offline alancalverd

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Re: It's possible to build a full size car that gets 200 mpg
« Reply #44 on: 04/03/2015 22:05:15 »
Alas, many work days involve 200 miles or more, and I like to spend some time actually working instead of driving, so I need a car that can cruise for a couple of hundred miles at 70 mph, which, according to the manufacturer, the Leaf won't. Even if time was immaterial, I worry about range after discovering, the hard way, that you can drive from Inverness to Perth (110 miles) on a Sunday without passing an open garage!

However warm the car is when you get in it, on a cold day it will lose about 3 kW of heat continuously (it's the 70 mph, -4 deg C draught and the fact that it is made of thin steel and glass that causes the trouble) so you need a heater for any trip longer than 20 minutes or so if you are going to see out of the windows. Waste heat from a combustion engine will do nicely, and not having to economise on headlamp power is a comfort at night (though LED headlamps make a lot of sense - I'll insist on them for my next car).

I seriously considered using an electric car for short journeys but it turned out that even a commute from Oxford to London was beyond the safe range of anything affordable. 

Just looking back at "UK Gridwatch" I note that on the coldest days in February, when total demand was at its highest, the contribution of wind power was.....zero (or certainly less than 0.2 GW - the graph is a bit small). Hardly surprising since prolonged cold weather in the UK is caused by a stable anticyclone. And hardly a great advert for the 12 GW of installed turbine capacity. Indeed over the past 12 months, wind power has never exceeded 50% of the nominal installed capacity and generally seems to be running at less than 15%. Part of the problem is the variation in wind speed across the country: when I wrote earlier that the wind here (in East Anglia) was temporarily calm, it was blowing a gale off northern Scotland but the forecast wind distribution was quite the reverse, so you can have a situation where some turbines are feathered to prevent damage whilst others, feeding into the same national grid, are in a dead calm. Thus the "economy" of an electric car is actually due to the absurd subsidy that Joe Taxpayer is providing to the wind farms, compared with the absurd tax levied on road fuel.

Anyway, to return briefly to the OP, I now note that at a steady-ish 70 mph my 2-ton estate car returns 54 mpg even with aircon, so the 200 mpg car is definitely feasible if you get the weight and aerodynamics right. A couple of years ago an entirely conventional 2-seat aeroplane met the challenge of 100 mpg at 100 mph for 2 hours. Way better than any electric car.     
« Last Edit: 05/03/2015 00:26:08 by alancalverd »
 

Offline alancalverd

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Re: It's possible to build a full size car that gets 200 mpg
« Reply #45 on: 05/03/2015 08:07:35 »
I just woke up with another sad thought about electric cars. Suppose everyone used them.

The recharge time is about 10 minutes per 30 miles. Motorway service stations are about 30 miles apart. A gasoline car need only refuel for 5 minutes at every 10th station, and a diesel at every 20th, but an electric will need to stop at every second station for 20 minutes.

So when you arrive at your service station to recharge your electric car, there will be 5 or 10 times as many cars ahead of you queuing for the "pumps", and each one taking four times as long as a liquid-fuelled car to recharge.  Not a problem in the middle of the night, but at peak times a 60 mile journey will consist of 1 hour's driving and at least 1.5 hours queuing to recharge en route, giving an effective cruising speed of 24 mph - you might as well use a bicycle or a horse. Unless, of course, the service stations are 10 to 20 times as big as they are now - with all the global-warming concrete that entails.

Perhaps the solution is to install charging points every mile along the hard shoulder: as electric cars are distinctly more reliable than i.c. vehicles, you won't need it for breakdowns any more.
 

Offline wolfekeeper

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Re: It's possible to build a full size car that gets 200 mpg
« Reply #46 on: 05/03/2015 14:14:11 »
No.

You're thinking 'filling station', a filling station is an expensive piece of kit that handles toxic, flammable, potentially explosive materials.

An electric charging point is just a parking spot next to a charger. The chargers only cost a few thousand, and they're not particularly dangerous. Electricity is safer than petroleum.

So you can afford to have many, many more of them. And you can add more at any time, they're relatively easy to retrofit.

And the charging spot makes money in two ways simultaneously, while you're using it, you're usually buying food and coffee, and it *makes* money from selling electricity to you.
 

Offline alancalverd

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Re: It's possible to build a full size car that gets 200 mpg
« Reply #47 on: 05/03/2015 16:38:00 »
So how many charging points will there be for each coffee shop?

If each charging point delivers 150AH in 20 minutes, the current draw per station is 450 amps. It cost me 50,000 to install a 2 x 400 amp transformer in a clinic in London, where the 11 kV supply was available under the adjacent road.* Adding one or two charging points to an existing motorway service station is not a problem as they probably have a 1000A incoming supply, but it looks to me as though you will need a minimum of 50 sockets at each station to prevent road rage - or people dying of hypothermia or heatstroke as they queue for the chargers. Plus a fair bit of re-education for the poor travellers who have to stop for at least 20 minutes every 60 miles (assuming there is nobody ahead of them in the queue for the socket).

My colleagues charge 70 per hour for travel. If four of us have to attend an event 60 miles away, that's 280 on top of the customer's bill. But if we use an electric car, the travel cost doubles because we have to drive more slowly** and hang around waiting for the beast to recharge before we can finish the journey. I don't see much customer satisfaction there. 

"Electricity is safer than petroleum" should be written above every electric chair. And, since the cars use lithium batteries, on every Boeiing Dreamliner that catches fire.

Rather like solar panels on the roof, and indeed wind power systems, the electric car favours the early adopter but will be a disaster if it becomes popular.



*And for what it's worth, the mains power supply is now so poorly specified and unreliable that I'm installing diesel generators in new clinics - I can't afford the downtime and damage caused by voltage drops, frequency fluctuations and total outages of the grid. So here's a neat scenario: a 2-hour blackout of one section of the M6. Right now, no problem: most people drive on to the next service station and only those in really desperate straits (maybe one car in 50) wait until the power comes back, whereupon they refuel in a couple of minutes and the jam clears. But with electric cars, half of all the traffic must stop at each station because they can't possibly reach the next one. Pandebloodymonium.


** Aerodynamic drag increases with the square of speed, whatever the drag coefficient of the vehicle. That's why electric car manufacturers specify range at 55 mph (US speed limit) and not 70.
« Last Edit: 05/03/2015 16:56:34 by alancalverd »
 

Offline wolfekeeper

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Re: It's possible to build a full size car that gets 200 mpg
« Reply #48 on: 05/03/2015 18:04:06 »
You might want to ask yourself whether infrastructure that lasts indefinitely and creates two income streams is likely to be a bad investment; we're talking about reasonably large numbers of chargers/parking spaces costing perhaps a sizeable fraction of a million in front of a retail property that costs far more than that and that attracts customers to the store.



« Last Edit: 05/03/2015 18:09:28 by wolfekeeper »
 

Offline alancalverd

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Re: It's possible to build a full size car that gets 200 mpg
« Reply #49 on: 06/03/2015 08:17:03 »
But the primary function of a car is to get from A to C without having to change horses at B1, B2, B3...

I do operate some properties in retail/professional areas. Normal storefront is supplied with about 10 amps per foot of frontage, so I might be able to supply one fast-charge parking space in front of a 20 foot shop without having to rewire the entire street, but if my neighbours do the same, we will need to  double the supply capacity of the street. This cannot be done in London or Birmingham - there isn't sufficient incoming feeder capacity - and is probably impracticable in every other city. Which is a pity, because these are exactly the locations where people do want to stop for an hour or so.  And just to make things awkward, most city councils would prefer people not to use cars for short journeys.

OK, let's look at motorways. You implement your plan for universal electric car use, the average journey speed is halved, and the footfall at each service station is quadrupled. But what is that footfall going to do? Eat and drink for 20 minutes every hour? You'll have a national obesity crisis on your hands! Buy mobile phones, camping chairs, and all the other crap they sell in such places? Or just run around screaming with frustration and smacking their equally frustrated children?     

3 am and your teenage daughter calls: "Dad, I'm somewhere in the Yorkshire Moors and my battery is flat". "No problem, dear, I've got a gallon of electricity in the shed...."

Sorry, my friend, but after a million miles and four children, I'll stick with diesel. Biodiesel or wind-powered hydrocarbon synthesis would be nice, but the essence remains: any practical vehicle must be quicker than a horse over 100 miles and have a range of at least twice the human bladder capacity. 
 

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Re: It's possible to build a full size car that gets 200 mpg
« Reply #49 on: 06/03/2015 08:17:03 »

 

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