Diesel-electric car

pongo6863

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Mr-D

War Hero
That's why it's got the electric motor, reversing away quietly whenever the boxheads come to visit
 
?Perhaps not ideal for cars then but why not use diesel-electric for commercial vehicles like 7.5 -12 rigid bodies or buses? It would give a lot more flexibility in terms of layout, do away with the propshaft and allow you to run the engine for maximum efficiency without needing dozens of gears.

The Belarussians of all people are working on diesel-electric tractors although they have some fairly horrendous voltages flowing around and half a dozen different motors.
 
Use either an external compressor QUOTE=Joe_Private;3649428]How do you recharge the air bottles?[/QUOTE]
 
Carry an electrical compressor,and plug it into the mains.

Where are you going to find a compressor. Do you have to buy your own, as it is not something you are likely to find in your average garage or workshop.
 
D

ddjond2

Guest
The short answer is yes..they can be built. Trains have used them for years. The problem is burning diesel has more pollutants, the engines are heavier and cost much more to design.
 
Carry an electrical compressor,and plug it into the mains.
The pressure they give in that link is 350 Bar (which is just over 5000 psi). This is well beyond the scope of the normal compressors used for air tools and spraying, which tend to be at a maximum 10 Bar (150 psi). The only commercially available compressors I can think of that would be of any use would be diving compressors, and a cheap one would set you back 2 or 3 grand. It would also take hours to charge a bottle of that size (a 10l bottle used for diving can take 30 mins to go from 150 Bar to 300 Bar, the bottle in that vehicle is 175l).
 
The only diesel-electric vehicle I have served on (a big grey ship) had to increase or decrease the power of the generators when more power was needed by the motors. I imagine that trains work in the same way (btw diesel-electric trains are only cost effective because of the track electrification programme). For a car to keep its diesel engine running at a constant speed, it would need a huge array of batteries - which rather spoils the point doesn't it?

Diesel-Electric cars are yet another example of a technology which is possible, but not practical.

(I'm not an engineer by trade, but I do know a thing or two about alternative energy)
Diesel-electric trains are totally independent of track electrification. It's the diesel-generator sets which supply the electricity to the motors. One advantage of the set up is that electric motors can supply the incredible amount of torque needed to get thirty five thousand tonnes rolling. Another advantage is that the motors can go just as fast in reverse as they do going forward, so it doesn't matter which way a loco is facing -- as long as there's a driver's cab facing forward on the front unit.

Another reason why diesel-electric systems are used on heavy trains is that you can reverse the polarity on the motors and convert them into generators. As the weight of the train pushes them along huge amounts of electricity are generated which have to be dissipated through an arrangement of red hot bars like giant air cooled toasters. The trick is that in forcing the generators to produce the electricity a very slight braking effect is produced on the rolling stock. It's called dynamic braking. With a train that's nearly three kilometres long you can get hundreds of metres of slack which would tear out steel couplings like rotten teeth if you tried to apply the wheel brakes in that condition. Dynamic braking allows the driver to bunch up the train and have it under control before he makes a brake application.
 
.... Another reason why diesel-electric systems are used on heavy trains is that you can reverse the polarity on the motors and convert them into generators....
On a purely pedantic note, power-reversal of a motor to turn it into a generator does not involve anything to do with altering polarity, all that is required is for the driven end to become the driving end eg attempt to slow the the train by slowing the motor, and the inertia will keep the wheels turning at a faster speed than the motor is trying to turn, which will cause the motor to generate electricity the polarity of which will be the same as it's supply, but at a higher potential. If it is being supplied by a battery, this higher potential will charge the battery.
 
From memory
The Liege forts of WW I where constructed to resist the Maximum Caliber of shell that, it was estimated, an invading German army could bring on the roads of that era and towed by Horse.

Dr. Ferdinand Porsche working for the Austrian Military designed a Gun Tractor that would transport a Larger Caliber Howitzer than the Belgians had constructed the the fort's defenses to resist.

Whats this got to do with this thread.
Well Porsche's Tractor used an Internal combustion engine (Can't remember if it was Diesel) to drive an electric generator which then drove an Electric Motor in each wheel Independently.

Fuel burners are Engines, Electric drives are Motors as any old Submariner will tell you.

john
And Diesel, like Steam produces it's Max Torque at Zero revs, which is what you want for moving large mass from a standing start.

Only write up I can find on the Gun Tractors.
"He also created the heavy artillery vehicles, known as Motor-Moerser, used by the German military to invade Belgium."

Read more: Ferdinand Porsche: Biography from Answers.com
 

pongo6863

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At last! OK, it's petrol-electric but it's the same principle.

car_shot_1.jpg

The Fisker Karma

Fisker Automotive
 

Higgs_bosun

On ROPS
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There is no such thing as a free lunch... Technology does not really exist to replace 'fuel'...except perhaps sail power! Alternative fuels are not effective even if carbon neutral... There will always be a thermal impact. No point using electric cars if the supply of power is from a huge dirty power station in the country. Even a horse drawn carriage has an environmental price to pay.

Let's say we harness wind or wave energy, tap into the Earths core, develop fusion etc... It is still too late to reverse global warming, it is past the tipping point. Manufacturing processes are still the problem and the only solution is not going to happen...

Thank goodness that there is more oil left in the ground than we have yet taken out... I own four cars and three motorcyles... petrol is excellent stuff... :)
 
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