What is best alternative to run cars at present ?

[neptune]

1 MPG = 0.41 Km/L
The best petrol cars in India with averages
Maruti Alto=13 kmpl in city and 18 kmpl on highways
Maruti 800=14 kmpl in city and 22 kmpl on highways.
Maruti Zen=18 kmpl in city and 24 kmpl on highways.
Diesel is legal and cheap in India , but these cars are not available in Diesel.

so best car in millage is ZEN with 55 MPG on highways !

 

[Nigel Goodwin]

In 2012, the most efficient gas only car tested 37 combined MPG.

Presumably that's only american cars?, the rest of the world do far better than that - and some small diesels do 100mpg.

In independent tests the performance of the Prius is laughable, and the economy nothing special.

 

[neptune]

Sun lights power is 164 Watts per square meter over a 24 hour day , average of all earth. (visible+UV+infrared)
Ironically The most abundant sunlight nation all oil rich nation, they least need it.
This power is too low for electric cars to run on, even if we make PV cells 100% efficient, which is impossible according to Thermodynamics.

There is no question of mechanical engine using solar power as losses will be more.

if we use fuel cells instead of PV cells we can travel during night/cloudy weather and will not use batteries
we can generate hydrogen through solar power, electrolysis of sea water, no matter how inefficient this system is but it will be renewable.
but fuel cell use hydrogen which is too risky to store.
Have i understood everything or am i missing something ?

 

[Nigel Goodwin]

1) Why are the valves actuated by the engine? Why not have them electronically/electro-mechanically controlled?

What would be the point?, it still requires the exact same amount of power to actuate the valves, and it still comes fromm the engine.

It would also be asking for disaster, any slight electrical fault would trash the engine.

 

[neptune]

What would be the point?, it still requires the exact same amount of power to actuate the valves, and it still comes fromm the engine.

It would also be asking for disaster, any slight electrical fault would trash the engine.

No Electronically controlled input of fuel is best best if efficiency is concerned, what he meant was no mechanical valve instead electronic valve. electronic valve consume much less energy then mechanical ones

 

[Nigel Goodwin]

No Electronically controlled input of fuel is best best if efficiency is concerned, what he meant was no mechanical valve instead electronic valve. electronic valve consume much less energy then mechanical ones

How would you suggest you could make an 'electronic valve'?, to replace those in the cylinder head?.

It's got nothing to do with fuel injection, which is about precise amounts of fuel, nothing to do with mechanical differences.

 

[BrownOut]

Presumably that's only american cars?, the rest of the world do far better than that - and some small diesels do 100mpg.

In independent tests the performance of the Prius is laughable, and the economy nothing special.

Yes, some cars can do 100MPG. None have ever been make to be practacle, though they might in the future Hybrid technology is reletively new, and plug in hybrids use almost no fuel at all. The Prius is among the most fuel efficient production cars ever made. Nothing laughable about that.

 

[tcmtech]

Why are the valves actuated by the engine? Why not have them electronically/electro-mechanically controlled?

Actually the design if the valve and camshast is surprisingly low power. The vast majority of the energy that goes into opening the valve and compressing the spring gets returned on the closing of the valve.

On one side of the camshaft power is used to push the valve open against the spring while on the other side of the camshaft lobe the spring now pushes back and now rotates the camshaft.

Even on a large V8 engine once all the valves and springs are in place turning a camshaft by hand is not all that hard. But if only one valve and spring are in place its nearly impossible to do by hand since its opening and closing forces are not balanced out by other valve springs.

 

[Nigel Goodwin]

Yes, some cars can do 100MPG. None have ever been make to be practacle, though they might in the future Hybrid technology is reletively new, and plug in hybrids use almost no fuel at all. The Prius is among the most fuel efficient production cars ever made. Nothing laughable about that.

Do you believe in fairies as well?

There are various production cars, and have been for a number of years, that give 100 mpg.

 

[BrownOut]

Do you believe in fairies as well?

Well, the numbers are in. I see nothing that says otherwise.

There are various production cars, and have been for a number of years, that give 100 mpg.

Baloney. I want some of what you're somking.

The only car that's been shown to come close to hybrid economy has been the 79 VW Rabbit. It was a flimsy, rinky-dink car with the worst recorded performance in history. The Prius has just as good economy numbers, much better performance numbers, and in a mid-size chassis. Not that I'm all in love with the Prius, but it represents pretty best in class for hybrids.

 

[tcmtech]

One thing I learned some years ago is that if you want fuel mileage numbers you always have sacrifices, its just simple physics.

Its sort of how you can have a car with a "100 MPG carburetor" and not be breaking any laws or thermodynamics or physics in general. The trick is you just have to use a very small carburetor to make it work and not care about how dismally slow your acceleration is or what your top speed is.

I would be so bold as to suggest that most of use here with any reasonable basic mechanical skills could make a high mileage carburetor system for any vehicle. Its rather simple really if you know how.

Take a common lawn and garden engine carburetor, the old 3 - 5 HP style ones with adjustable main and idle jets, and simply make an adapter plate that allows it to fit where your vehicles present carburetor or throttle body is now. Hook up your throttle linkage and fuel line to the tiny carburetor and adjust the jets to get the best running power you can out of it. If its a fuel injected engine disconnect the power to the fuel injectors of course.
If you have an engine with a regular distributor type ignition you can turn the base igntion timing considerably further positive as well which will gain you a little more mechanical efficiency. Normally doing so would cause hard knocking and pinging but the tiny carb wont let enough fuel and air through to cause this problem even at full throttle.

Now go for a drive! thats it, thats how you get a substantial gain in your fuel mileage numbers. The only down side is you will get passed by preschool kids on their tricycles and you will have the acceleration of a fast glacier but hey your fuel mileage numbers will top anyone else!

Lastly dont forget to put one of those slow moving vehical triangles in your back window.

 

[tcmtech]

What I have found is that those 'super efficient econo cars' tend to be nearly no different or in some cased worse that any other car when driven just like any other car.

I drove my aunt and uncles new Prius a while back for a long distance trip and this is what I found from first hand experience. I was not impressed by the way.
https://www.electro-tech-online.com/threads/i-drove-a-new-prius-for-the-first-time.100081/

When driven like a normal car it get normal car fuel mileage. When driven ultra conservatively it gets higher fuel mileage numbers thats all there is to it.
Perhaps its a bit more efficient in town but for the up front price tag involved that little bit of added in town fuel efficiency will never pay for itself in avoided costs on any practical working life time and it certainly could get its economic butt handed to to by a good deal of other cars in its similar size range, even ones from more than just a few decades ago.

 

[BrownOut]

Consumer Reports tests many cars and ranks them for economy, performance, etc. The Toyota Prius came in third overall, and first among cars that doesn't 'plug in' On CR's 150 miles trip, the Prius got 53MPG, as measured with precision fuel flow meters. The closest fuel only was the rinky-dink Smart For Two, which got 46MPG. All cars were tested in equal driving conditions. This is an independent test using precision measurement methods. source

 

[BrownOut]

It looks like there are a couple high MPG cars on the market, the Daihatsu Charade 993cc turbo diesle 100MPG. It is not widely available, not sure why. It's a "supermini" which probably means you don't want to take it on long trips with your faimily. link Also, the Volkswagon Polo, another 'supermini' at 74MPG. The Honda Insight achieves 48MPG under real-world driving conditions. There isn't many more that can beat that. When measured in consistant units, the Chevy Volt comes out at the top of the list, at 36kWh per 100 miles, that's more efficient than wakling.link

 

[BrownOut]

Now if you really want efficiency, the VW L1 diesel/electric hybrid gets 240 MPG. link Beat that gas-only drivers!

 

[alec_t]

Question: How many gallons of oil have to be burned at power stations to create the electricity to charge the batteries of these hybrid cars? If that's factored in I suspect the hybrid MPG claims take a considerable knock.

 

[BrownOut]

Most electricity in the US comes from natural gas generators. Hybrids aren't actually plugged in to charge the batteries, unless they are 'plug in' hybrids. The conventional Prius, for example' is not charged by plugging in. Even so, don't think they would take much of a knock, domestic electricity is cheap for a reason, and its probably because it can be produced more effeciently than motor energy. Also, here in the Tennessee Valley, we get much of our electricity from water power and nuclear plants, so very little fossile fuels are used.

 

[alec_t]

domestic electricity is cheap for a reason

It might be in the States. It sure isn't over here!

 

[BrownOut]

I've looked at numbers that show cost per mile ( or km ) for electricity vs gas for both the US and Eurpoe, and electricity has been cheeper in every document I've looked at. Further, when the energy per mi ( or km ) is converted to a consistant unit of measure, kWh for example, electric cars are measurably more efficient.

 

[Nigel Goodwin]

It looks like there are a couple high MPG cars on the market, the Daihatsu Charade 993cc turbo diesle 100MPG.

See - if you look, you find

A quick google soon finds:

Most Fuel Efficient Cars

This table shows the top 10 most fuel efficient cars that you can get in the UK today, based on their Combined fuel efficiency figure. Unsuprisingly, diesel superminis are dominating the top positions.

What we thought was fairly interesting was that the Toyota Prius - long hailed as the defacto "green" car - just scrapes into our list at 10th place! However, to be fair on the Prius's electric benefits when we look at only the urban cycle (not shown here) the Prius comes in in 4th place, behind the Insight, and C3 and C2 1.4 HDI SensoDrives. All this leads us to one question - when are the car manufacturers going to start making a hybrid diesel supermini?

Manufacturer Model Specification Fuel Type Transmission Combined MPG VED Band HONDA Insight Insight Petrol Hybrid M5 83.10 A CITROEN C2 1.4 HDi Diesel M5 68.90 B CITROEN C1 1.4 HDi Diesel M5 68.90 B RENAULT Clio 1.5 dCi 80 Diesel M5 67.30 B CITROEN C2 1.4 HDi SensoDrive Diesel A5 67.30 B CITROEN C3 1.4 HDi Diesel M5 67.30 B RENAULT Clio 1.5 dCi 100 Diesel M5 65.80 B RENAULT Clio 1.5 dCi 65 Diesel M5 65.80 B CITROEN C2 1.4 HDi Diesel M5 65.70 B TOYOTA Prius 1.5 VVT-i Hybrid Petrol Hybrid E-CVT 65.70 B

Your wonderful Prius only scrapes tenth!.

Damn! - formatting won't hold, here's the link:

http://fuel-economy.co.uk/stats.shtml