Electric bus

[artvonne]

  That darn Prius. Ya know, if ya yanked the motor and dropped in a 1979 VW rabbit diesel with a 5 speed, and set it up right, it could almost double the fuel economy. And imagine if it had a 1 liter intercooled turbo diesel. I bet 100 mpg could be reached easily.

  Maybe in another 30 years.
 

[coconut990]

I guess no one have seen a train which is diesel and it is electric. We have had trains as long as I been alive. What you have is a diesel engine that turn a generator for the power. I have talked to them about it I was told it make for better saving. I am not talking about electric only. A bus with a phase 3 motor A/C at 500 volts will have up to 400 horse power and that pull the bus. You could use a smaller engine which you could get up 15 miles per gallon of fuel and with battery pack you could have up 35 miles per charge. The diesel engine waste power with heat not saying the electric motor don't make heat just the electric motor don't lose power from the heat and with the electric phase 3 motor with regenerative braking could regain power.

[Oonrahnjay]

(snip)  And imagine if it had a 1 liter intercooled turbo diesel. I bet 100 mpg could be reached easily.

I dunno, Art.  The only reason that currently available 'hybrid" cars can show any benefit is to try to balance the inherent poor efficiency of the gasoline energy in ways that overcome the extra weight, mechanical complexity, and internal drag of the hybrid machinery.  With a modern diesel, there's no "fat" to cut out by the hybrid complexities.  My guess is that a hybrid diesel with a small diesel engine would give *lower* MPG in city and highway driving - and way lower on the highway.

[Jeremy]

Thinking of a diesel-electric bus as equivalent to a diesel-electric train is an attractive idea, but not necessarily logical. Firstly, diesel-electric propulsion is not done for economy reasons, a direct-coupled diesel being inherently more efficient than one which sends it's power through the extra (loss-making) electric generator / electric motor stages. Having said that, there is a small economy gain from the diesel engine operation itself, because in a diesel-electric the engine can operate over a much smaller speed range.

The reason why diesel-electric systems are used for trains is because they are so damn heavy - hundreds, if not thousands, of tons. The electric generator/motor is effectively doing the job that the clutch or torque converter does in a vehicle with a direct-connected engine - the 'electric' option being used on a locomotive because it would be impractical to build a conventional gearbox that could handle the amount of power and huge weight involved.

Jeremy

PS. 100mpg cars are nothing new. Almost 20 years ago my Dad had a string of Montegos with the 2 litre Perkins Prima diesel. The car was advertised as being capable of both 100mpg and 100mph. And it absolutely was (although not at the same time sadly). There are lots of diesel cars now that can achieve this (bearing in mind that our gallons are slightly bigger of course)

[Sean]

I guess no one have seen a train which is diesel and it is electric. .... What you have is a diesel engine that turn a generator for the power. I have talked to them about it I was told it make for better saving.

You can't really compare full-size trains with buses.

Diesel-electric locomotives are built that way because the electric motors deliver better tractive effort from a standing stop.  It would be prohibitively large and expensive to try to build a mechanical drive system that would let you start a loaded train from a stop with the size diesel that is in a locomotive.

By contrast, light diesel rail cars such as the Budd RDC traditionally had mechanical drive systems, not all that different from a modern Allison, precisely because the fuel mileage was better in that application.

As a side benefit, electric traction motors allow you to use dynamic braking (not to be confused with regenerative braking) on long downhill runs, which helps prevent runaways.  On some grades, dynamic braking even allows you to skip turning up the retainers, a huge savings of time and effort.

I am not talking about electric only. A bus with a phase 3 motor A/C at 500 volts will have up to 400 horse power and that pull the bus. You could use a smaller engine which you could get up 15 miles per gallon of fuel and with battery pack you could have up 35 miles per charge.

Really? I'd love to know where you are getting these numbers.

The diesel engine waste power with heat not saying the electric motor don't make heat just the electric motor don't lose power from the heat

Umm, sorry, but yes it does.  Every watt dissipated as heat is a watt not used for propulsion; it doesn't matter whether that's an internal combustion engine, an electric motor, or a pair of oxen.

and with the electric phase 3 motor with regenerative braking could regain power.

OK, here you are correct.  In fact, this is the major significant energy savings of hybrid propulsion.  That being said, however, you need to have enough batteries to store the regenerated energy to be effective.

With today's technology, that translates only to stop-and-go driving.  IOTW, you can make productive use of regenerative braking coming up to a stoplight when the light again turns green and you step on the go pedal.  But there is no way you can use regenerative braking to, say, recover the energy expended climbing Donner Pass when you come back down the other side.  The best you could do would be to have some kind of dynamic braking, just like a locomotive, where you can dissipate that energy directly as heat in order to prolong brake shoe life.

FWIW.

-Sean
http://OurOdyssey.BlogSpot.com

[Jeremy]

Mention of regenerative braking reminds me that I saw a feature on TV once where some transit buses here had compressed air regenerative braking systems fitted. These were conventional diesel buses with some sort of air motor assistance - the braking action (eg arriving at a bus stop) charged up an air cylinder, the energy in which then assisted the diesel engine as the bus accelerated away again.

Jeremy

[Oonrahnjay]

Mention of regenerative braking reminds me that I saw a feature on TV once where some transit buses here had compressed air regenerative braking systems fitted. These were conventional diesel buses with some sort of air motor assistance - the braking action (eg arriving at a bus stop) charged up an air cylinder, the energy in which then assisted the diesel engine as the bus accelerated away again.  Jeremy 

      There was some work a while ago on flywheels being the energy storage mechanism.  As the bus stopped, the energy spun up a bigga$$ flywheel; when the bus was accelerating, the energy was taken out of the flywheel with a clutch to the transmission.  Once that oomph was gone, the flywheel would be released and the ordinary engine was engaged.  Dunno if it really works -- has the same problem as hybrids, you're hauling big stuff that takes energy when you're not using it. But nothing about that takes away from the truth that -- for our purposes -- there's no practical technology today (or on the horizon) that allows us to even think about "an electric bus".

[Iceni John]

A year or two ago Interschola sold an electric Blue Bird school bus:  http://www.interschola.com/displayitem.php?items_id=14272
I'm not sure why anyone would buy it for $2550, even if it had nice wheels.   Maybe the buyer bought it for all the lead in its batteries  -  heck, you could probably get more than the selling price by scrapping it.   Several things intrigued me about that bus:
1.  Only 6337 miles in ten years?   Looking at the amount of dust inside, I'm guessing it wasn't used at all for some of that time, but that's still not an impressive annual mileage.   Darn, I ride my bike more than that!
2.  What's with a six-gallon tank for a diesel generator?   Was this some ante-Prius hybrid, or maybe it was for an emergency get-you-home engine after the batteries die twenty miles from the nearest charging outlet?
3.  An unladen weight of almost 33,000 lbs!!!   That's A LOT of batteries to make a TC2000 that heavy.
4.  The motor's serial number is 0002.   Would you want to use only the second of anything ever made?
5.  Interschola says the transmission is Automatic.   I hope that's a simple mistake, because I've never heard of an electric motor that needs an automatic transmission.   Strange.
6.  I suppose the nice Alcoa aluminum wheels are to save weight, maybe!?   Don't the studs seem kinda short  -  I don't see much threads showing beyond them.
7.  It has a 90,000 BTU heater.   It would need a busload of batteries just to power that, unless it used the diesel generator to make power to run the heater!   That seems like a strange way to keep the little sprogs warm in winter.
8.  This bus came from Beaumont, out near Palm Springs, one of the California's hotter places.   Why not carpet the roof with PV panels to help charge the batteries, and keep it slightly cooler in hot weather.   Nah, that would be too sensible.

So, there are battery buses out there, but not what any of us would find very useful.

John   

[Iceni John]

The reason why diesel-electric systems are used for trains is because they are so damn heavy - hundreds, if not thousands, of tons. The electric generator/motor is effectively doing the job that the clutch or torque converter does in a vehicle with a direct-connected engine - the 'electric' option being used on a locomotive because it would be impractical to build a conventional gearbox that could handle the amount of power and huge weight involved.

Remember the Fell?   http://www.paxmanhistory.org.uk/paxfell.htm   This was a mainline diesel locomotive with a purely mechanical transmission, and it really didn't work very well (or sometimes even work at all).   If Rube Goldberg had been a locomotive designer, he would have criticized this contraption for being too complicated.   Six engines (four to power it, and two more to supercharge those four), a transmission that is almost incomprehensible, and apparently it was deafeningly loud.

That's why purely mechanical transmissions don't work on locomotives!

On the other hand, hydraulic transmissions have been used effectively in Germany and Britain for mainline locomotives.

John

[happycamperbrat]

Lots of naysayers on this site regarding electric vehicles...... yet alone electric buses. My advice would be to go to this site http://www.diyelectriccar.com/forums/ They have very knowledgable people on the latest cutting edge batteries and people doing a lot of experimentation as well as tried and true works on electric vehicles. Good luck!

[Jeremy]

A couple of years ago I heard a radio programme which took the form of the audio diary of a couple of guys driving a milk float from Land's End to John o' Groats (ie., the full length of the UK). I don't know whether you have milk floats in the USA, but basically they are electric vehicles (for quietness) which deliver milk door-to-door early in the morning. Their maximum speed is probably 10-15mph.

Anyway, these two guys had a marvellous time on their adventure, traveling a few miles each day and meeting lots of interesting people as they begged the use of power sockets in which to plug the recharging lead for their vehicle. I don't remember how long the trip took, but obviously it was a number of weeks.

I'm not saying that an electric bus would necessarily have the performance of a milk float, but just pointing out that an electric bus could become a viable proposition if you radically change your traveling behaviour and expectations

Jeremy

[belfert]

I suspect that electric school bus was only listed as an automatic because the choices are probably only automatic or manual.  You don't need to shift so the automatic choice makes the most sense.  The heater says it is 12 volt so it probably burns diesel to make heat.  The size of the copper wire required to produce 90,000 BTU at 12 volt would make 4/0 look tiny.  The diesel tank is likely for the heater.

Is the whole undercarriage filled with batteries?

[Oonrahnjay]

(snip) I don't know whether you have milk floats in the USA, (snip)

     I've never seen one in the US but I saw a number when I lived near a Midland Dairies depot in Wolverhampton -- if it was after 8 AM, they were usually being towed back to the depot by a team of horses.  (Yes, there's lots of dirt out there younger than I am ...)

[Len Silva]

Lots of naysayers on this site regarding electric vehicles...... yet alone electric buses. My advice would be to go to this site http://www.diyelectriccar.com/forums/ They have very knowledgable people on the latest cutting edge batteries and people doing a lot of experimentation as well as tried and true works on electric vehicles. Good luck!

Not so much naysayers as pragmatists.

We, as Busnuts, all appreciate experimenting and developing new ideas; sometimes, the further out of the box, the better.

As long as you are talking about experiments, learning, trying new things, etc., then I think we are all behind you.

If your goals are environmental, experiential, pushing limits just for the sake of pushing them, go for it.

If, on the other hand, your goals are economy, especially on a limited budget, then I think you are kidding yourself.

Some of the experimenters on the diyelectriccar forum are claiming a 3-400 mile range which is great.  They are mostly flatland and moderate temperatures.

I commuted for many years fifty miles each way, running 70-80 on the interstate in the Florida heat, air conditioner running full on.  I doubt any of the available cars could do that.

The winter cold could be taken care of with gasoline or propane heat, but the batteries would suffer reduced output from the cold.

Something I learned in a quick perusal of the website suggested that your VW Bus might not be the best choice because of the large frontal area (They were talking about a Ford Ranger being too big, yours is considerably larger).

A recent newspaper article suggested that if all the people who worked in downtown Tampa and lived in the North Tampa suburbs drove a Nissan Leaf and plugged it in at 5:30 every evening, they would quickly overwhelm the power company.

Not nay-saying, just suggesting a lot of unemotional, practical thought go into the process.

[happycamperbrat]

Something more arrow dynamic then a brick is great! Always! And the smaller more expensive batteries can be used in a smaller car to make them very efficient.

But I chose the VW bus because of it's sturdy construction and weight holding capacity, as well as looks. I can use heavier lead acid batteries, or go with the more expensive lighter batteries. In this article it is said to be the a great platform for an ev http://www.didik.com/criticalev.htm