Tuesday, January 25, 2011

Cars-driven-by-compressed-air

What are compressed air driven cars like?

There are some subjects one needs to understand technically to write about, and engines are one of them.
Science is another. The problem with the compressed air driven car is the science it is based on, not the pure mechanical operation of the motor itself.
To convert compressed air to power at the wheels means huge losses in conversion.
The car still has nowhere near the touted performance and in my view will not do much better in the future if they continue trying to get this lemon up.
The first compressed air propulsion car has been around since just after the birth of the motor car itself.
It died a quick death not because they built it wrongly, after all we have not changed chemistry physics or math that much since then.
No, they missed the same things then as now. It is massively impractical to convert to compressed air power and store it for use in a motor vehicle.
The first compressed air car was built in 1860.

The new compressed air car.

claims of 80% fuel saving and 110kph (70mph)have been made for this new compressed air car. Click to enlarge picture.
The compressed air motor

First compressed air cars

Compressed air cars in the past. Here are the two most successful early contenders. Click to enlarge picture.
Here is an amazing picture of two early compressed air driven cars.
There were many reasons why compressed air cars were not successful then, and indeed are not marketable now, despite the many attempts every few years to makes a new compressed air driven vehicle.
Here are some of the problems. Others can be found from links on this page.
  • Infrastructure costs and feasibility of fuel delivery systems.
  • Energy loss due to energy conversion.
  • Energy loss due to extreme temperature.
  • Primary pollution from the supply of the fuel.
  • A lack of horsepower
  • Poor reliability compared to ICEs.
Early compressed air developments that were unsuccessful can be an authoritative guide to today's efforts too.
Despite the apparently unassailable knowledge and expertise of those associated with the new compressed air car efforts, yet again their common sense is in doubt, not their skills as engineers..
The Renault racing team development engineer who designed the motor has fulfilled many promises with the engineering, but not atypically for motor engineers he can't see the elephant in the room.
Having been around engine development for about a hundred years, I have seen many advances in Internal combustion engines which this compressed air engine resembles but over the years I have seen engineers make something beautiful, many times but not see the whole picture .
Bringing new technology in to being can be misguided if it involves the transference of energy from one source to another eg; electricity to compressed air.
This involves huge energy losses all the way through the process and requires new and doubtful infrastructure as well, in the form of air compressors in filling stations that will use masses of electricity to run..
1400 psi is a lot of pressure and normal garage compressors can only produce about 150 psi, and even at this pressure works so hard they create enough heat in the process to wear out pretty quickly with daily use, and of course the heat is lost energy so that I can't see how it would be as cheap as 2 bucks to fill. Makes no sense.
The car, is hyped as "pollution free", but of course there will be enormous amounts of electricity required to fill these huge tanks to this pressure.(currently produced by filthy brown coal in Victoria and for that matter most of the world) so this is a very loose definition of pollution free. What they should have said is that the exhaust emissions are clean, not the fuel.source.

Imagine what this would cost to run?

A large air compressor

Fueling a compressed air driven car..

Fuelling a compressed air car sounds easy and clean.
Electricity is needed to drive the air compressor needed to pump an enormous amount of air in to the tanks against aback pressure of 1400 psi.
Your local service station is not going to have enough electricity in the supply line to feed that mutha!

Claims of 70mph or 110 kph are rubbish.

The car cannot produce enough horsepower to maintain this speed.
The car as it was demonstrated never got up to traffic speed and the air motor sound like a worn out piston motor with far too much mechanical noise and very little power.

Latest compressed air car news.

April 2010. I'm still waiting for that car guys! America will have a full range of these wonders by 2010 according to the latest press. I still believe it is all Bull-dust!
They have made some cars, but they will never make it in to full production because the whole premise is wrong. Now read on to find out why.
the new compressed air car.has been featured on tv and in major press around the world for 3 years now.

Hopeful buyers are lining up

All are happy to part with a measly $8000 for a car that is 80% more fuel efficient and will do 110kph or 70mph.
This is a small very light vehicle which is touted to be able to travel 200 klms on a fill costing about $2.00
India's largest car maker Tata is involved according to several articles.

With Tata's billions in sales we have credibility laid on.

Huge Kevlar tanks hold the compressed air at 1400 psi mounted to form part of the chassis.
The air tanks are designed to split open at a pre-determined point, unloading the air through a large seam crack to reduce pressure and discharge safely in an accident.
The Australian AGE newspaper had an article in December 2007 that excited we soon to be lucky Melbournians.
$1.5 Billion dollars to be invested in Australian manufacturing plants starting with a plant right here in Melbourne.
The problem is despite the many Press write ups, this wonderful fuel saving car has yet to emerge.
I will not pretend that I am as authoritative a source as the AGE or Business Week.(who also ran a big story,) or the TV networks, but this is my hub, and I am going to say what I believe to be true anyway as my friend agvupes on hubpages asked me about the compressed air car and this is my honest answer. I respect him so I will speak without fear or favour.
My opinion is that the compressed air car project will not get off the ground.
As far as I know it has only been tested around the block because that is as far as it will go. I can find no reliable pictures or other evidence to show otherwise..
110 kph or 70 mph? NO WAY.

Baby air car

Not much chance of passing safety legislation!

Compressed air driven car back seat.

This compressed air driven car would not go far with a full load. Weight is crucial with so little power!

Why compressed air cars won't work.

Consider the following:

A standard air compressor used in an automotive workshop to inflate tyres, run a few air tools and a tyre changer at 150 psi Costs $1800 to $3.900 dollars to buy, and uses a 7-10 hp electric motor.
But to push in 1400 psi I'd guess at upward of $100,000 each for a compressor for this application, and a lot of horsepower.
The test drives that have actually been done with this car cover only a very short distance, and I may know why.
According to some mathematical calculations if the compressed air car is driven constantly at 110kph it will only travel about 4-6klms on a full tank!
I have not done the math but it is out there on the net.
I also believe the whole process is deeply flawed in it's conception and is yet another hair-brained idea to replace ICEs.

But wait..... there's more!

A new air car has been announces for the American market that will do a 1000 klms or so with 70hp on tap. I will believe that when I drive it.
You are wise in doubting the compressed air driven vehicle agvupes.

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