Hybrid diesel trucks with no transmissions in our future?
More powerful than a locomotive? That's what the folks over at Diesel Power are predicting for the future of trucks. Cars and trucks have become more powerful over the years, with today's torque figures dwarfing the 420 ft.-lbs. of torque figures commonly seen in trucks in the mid-1990s. While many factory numbers hit above 500 ft.-lbs. and aftermarket parts can launch drivers above 1,000 ft.-lbs., we have to be nearing the threshold of how big and bulky the transmissions can get and still be efficient, right?
Here's where Diesel Power caught our interest -- a hybrid-electric diesel, except not the kind you're probably thinking of. Something a little more conventional, just not in the automotive world. The idea is that the diesel engine will power an electric motor on each wheel, putting out close to 2,000 lb.-ft. at 0 rpm. Like a locomotive engine, the diesel engine would run at a near-constant speed -- circumstances that run the engine at its most efficient. It may not be technology that will hit the streets anytime soon, but it's certainly something to watch out for.
[via Diesel Power]
Reader Comments (Page 1 of 1)
Haisano 7:43PM (10/16/2006)
HAHAHAHAHAHAAHAAHAHAHAHAHA
*Snort*
Sorry, but "more powerful than a locomotive?!"
Hokay, nothing wrong with Autoblog's report, for sure. But today's locomotives average 4,500 to 6,000 hp each. Out of a single V16 with each cylinder displacing more than twice that of a normal car engine. No way in hell is a truck getting even close.
Oh, and don't forget the torque (tractive effort) of 200,000 pounds. Stick that in your pipe and smoke it :P
Now, as for the transmission, most Diesel-Electric locomotives do indeed have a variable output motor. Locomotive engines rarely spin at more than 800rpm, and that's wide open throttle. They do indeed idle and go up and down the rev range -- only some types of passenger locomotives operate at a constant throttle rating, which is wide open, and those are being retired quite quickly.
However, the idea of placing electric motors on each wheel has been researched for quite some time. Acura did so in the late 80's and early 90's, iirc. The problem is one of size, cooling and weight. Also, add to the fact that unless it is an AC motor, you can't try and use it to brake (other than regenerative braking, which is not a very powerful force, just constant). The motors also keep you from placing brake rotors in the same spot, unless you move it back to where the axle is.
Basically, to do it right, you'd need an AC transmission. You have a diesel engine, alternator, rectifier, inverters which convert to DC, more inverters back to AC and then the motors. You have to go AC-DC-AC because AC motors will tend to rotate at a speed in line with the hz/cycle of the current, iirc, and that means you can't control them well. You invert to DC and then back to control the motor speed. This is all a lot of equipment and weight, which can also fail, and needs to be cooled and maintained.
It's an interesting idea, but unless they've developed the technology to cram everything into a car frame it won't be effective for a long time to come.
We shall see, I guess. I look forward to finding out what happens.
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Kurt 9:39AM (10/16/2006)
Now, finally, a vehicle for those of us that would rather drive an EMD SD70MAC.
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Armand 9:43AM (10/16/2006)
High displacement high power trucks for the masses are living their last hour, once the legislation is in place to consider passenger trucks like cars they will simply go back to the niche they should have never left!
Unless you are talking about long haul trucking (the real trucks, not the truckettes!) this technology will not see the day of light any time soon.
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jordan 9:48AM (10/16/2006)
Actually, this is already available. A few buses in New York have been replaced by Diesel hybrids. The diesel motor runs at a constant speed (in the 1500-2000rpm range I think) and charges a battery which powers an electric motor. They did this to improve both durability and efficiency. I think the milage on the buses changed to 3-4mpg, up from 1-2. Now, it might not sound like much, but that's double what it made before.
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sp 9:58AM (10/16/2006)
its called CVT
:-).
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The other Bob 10:08AM (10/16/2006)
No, Its not a CVT.
It's much better. I always thought this was the smartest thing to do with Hybrid technology. Just eliminate the transmission and make the electric motor the primary drive. It's like adding a generator to an EV1. It also allows the engine to run at its most efficient.
While the trucks in the story will not have huge batteries, that would be the next step to apply this technology to a passenger car.
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Tim UF 10:19AM (10/16/2006)
yea, a lot of road going diesels have this already, most notably, busses, as jordan (#4) posted.
means you have a generating and motor no gears required
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Joe 11:56AM (10/16/2006)
Icebreakers use this technology so that they don't have drivetrain backlash if a chunk grabs the screws. It has been in the Navy for decades.
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Gary 12:01PM (10/16/2006)
The problem with this idea has always been weight. The Navy used to use this system, but dropped it because of the weight penalty. Granted, that was 70 years ago and technology has improved, but NON-electric technology has ALSO improved.
If you have, say, a 500 HP diesel, then you need a 500 HP electric motor, and a 400 kW generator. That won't matter much on a really huge truck (or a city bus), but will on a mid-sized (GVW class 4/5/6) or small truck.
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Mr_Oak 12:03PM (10/16/2006)
4. Actually, this is already available. A few buses in New York have been replaced by Diesel hybrids.
I always wondered how what the exact numerical value of the term "A Few" was. Thank tou for resolving that for me.
A Few = 550.
550 = the number of Hybrid buses in service in NYC.
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tbyron 12:55PM (10/16/2006)
There is a company in California that has been doing this for a while, providing trucks and buses with this sort of series hybrid (v. parallel) systems for a while. To me, one of the interesting things is that they are able to get very similar performance and economy results from Ford gasoline V10's while yielding a superior emissions profile.
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tbyron 12:59PM (10/16/2006)
Forgot the link to ISE Corp, that company:
http://www.isecorp.com/
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tigra 1:24PM (10/16/2006)
Not sure about other competitors, but Belarusian BelAZ (http://belaz.minsk.by/about/?lang=en) super-heavy haulers use this approach for ages. There is nothing really new about this "hybrid" diesel.
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Dan 2:44PM (10/16/2006)
In 1993, under DOE's "Partnership for a New Generation of Vehicles" (PNGV Program), the Big 3 each developed a Diesel-Electric Hybrid that eliminated the mechanical drive line in favour of either series or parallel electric drive with electric motors/generators at each wheel. The cars were the Ford Prodigy - 70 MPG, the DaimlerChrysler ESX3 - 72 MPG, and the GM Precept - 79.6 MPG.
These full size sedans achieved between 70 and 80 MPG n 1993!!!!
The advantages for all size vehicles can be significant in terms of simplicity, milage, low maintenance, intelligent all wheel drive, safety, much lower emissions, etc. etc. Combine the use of Bio-Diesel with these hybrids and the USA would not need to import a single drop of foreign oil nor would we need to send our money to those in the Gulf who want to kill us. What are we waiting for?
The first company to offer this type of Bio-Diesel Hybrid is going to be a great success in more ways than just profit. The potential is vast as this technology can reshape surface transportation in America without needing to change basic infrastructure.
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Barney 8:40AM (10/18/2006)
re # 14,Haisano:
I agree with what you say but technology has changed perspectives considerably over the years. Like reciprocating engines, smaller electric motors have replaced the heavy ones with even more power. It was amazing to see a four cylinder surpass the 100HP mark and 50 HP electric motors weigh less then 200 lbs.
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Bob 3:27PM (11/29/2006)
All this is nothing new. Its actually very old technology. It's been used on large mining trucks, and heavy equipment 50 some years ago. Reason it isn't now?
Its a very inefficent way to transmitt power from a heat engine to the wheels. And costly by todays standards. First the prime mover has to turn a generator or alternator, many losses in this process.
Just go purchase a small genset for those stormy days.
So that 5000 watt genset has a 10 plus HP engine on it. You say ah so what. 5000 watts is 6.7 hp. So why do you think it needs a much larger engine? So you waste about 30% right off the bat. Then you gotta run the wires and switching to the traction motors. Then the traction motors themselves have their own losses.
Funny how the trend in the big mining trucks is to use a transmission now instead of diesel electric. I even remember reading some time back, some talk about getting rid of the electric power in locomotives and going trough a transmission. Oh and you won't find a CVT in a mining truck ever. They barley work in a drill press.
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