Please tell me if I'm way out in left field and have no idea what I'm talking about.

I was watching the History Channel (dont laugh) the other day where they had a show about trains. They talked about deisel engine trains and that they arent actually propelled by the engine, rather the engine <U>directly</U> drives an electric motor. The advantage of this is the elimination of a transmission making the power application direct drive.

Now, I know current hybrid cars have small gasoline engines <U>recharging</U> batteries which in tern <U>send power to a transmission</U>. So I'm thinking why not have a fuel efficient diesel <U>directly</U> power a direct drive system or even a CVT.

Only argument I can see is that it would need to spin at a very high RPM but the CVT would fix that, but I'd like to here some other opinions.

 

i can see where you're coming from...but deisel engines are (as far as i know) used primarily for reliability and not performance. plus, if you're going to have 1) an engine driving 2) an electric motor being kept alive by 3) a hefty high capacity battery(s)...that's a lot of extra weight that would counteract the pros of having a "direct drive" power application (less loss of hp when you don't have to go through a trans.) plus....who wants to drive around with a diesel engine clanking away

 

...and they smell like azz.

 

Look at all the new cars coming out, I dont think they care about performance all that much--fuel efficient this, and environmentally friendly this, and OBD74.8 this . Also, I dont think batteries would be necessary since the motor would be driving the motor directly and not charging any batteries.

 

hey, i'm all for new engine designs and setups. i think innovation is what got the import scene to where it is now (tech wise). i don't have anough technical knowledge about what it would take to make the setup you're proposing work...so i really don't know about the batteries and all that... i just know that diesel engines have never been made to handle high RPM levels or really that high of HP levels either....they're all about torque.

 

hell I split my time between speed and the history channel.

gearing would still be required in a application where fast accel. was important. To much weight.

 

I dont know all that much either, and I obviously dont know about all the details involved, I'm just proposing a general theory.

 

isnt there a volkswagen somewhat related to what you are saying....its like a vw tdi or something...correct me if im wrong....

 

To get decent power, you need a pretty strong diesel engine to spin the turbine. That takes up alot of room and adds a lot of weight. Remember, most of those train engines are 186 liters in displacement (V16's). Power output is sweet tho'. Most are around 4,000hp at 900rpm and 28,000ft/lbs of torque at 900rpm.

 

that is an interesting question....I have another theory along the same lines. Panoz did something somewhat similar a few years back to their LeMans car. Take the electric motor from a hybrid civic or insight, and sandwich it between an RSX engine/tranny since the electric motor is only a couple inches thick. You get all the power of the KA20, plus an 'electric' supercharger that you could have come on whenever of where ever you need the boost in hp/tq. Fuel efficient, hybrid race car? I think it's feasible.


[Modified by carl_aka_carlos, 9:48 AM 9/24/2002]

 

Here's another interesting twist in this thread y'all might enjoy.

Sure, it's not diesel, but it goes.

 

Here is a hint that might help understanding the diesel electric train. Typical train is 100 cars, each grossing 300,000lbs. That is 30,000,000 lbs for the train. Typical diesel train engine is around 4000 hp as said below. HP/ weight ratio = 0.000133 hp/lb. Typical type R about what 150 ponies and 2500 ish lbs = 0.060 hp/lb. a difference of a factor of 450 or 45,000 percent.

The train is all about reliable torque multiplication to get that beast moving...... and braking. Think how many stages (of gear reduction) one would need to slip the clutch to start a 15,000 ton object moving. Then running thru the gears to get it up to 50 mph or so. What maybee a 300 speed transmission?

For cruising mpg in our cars, we need high efficiency. Perhaps 0.9 for a generator and 0.9 for a motor = composite efficiency around 0.8. Gearboxes do better. Some highly polished, single stage boxes only loose 3% or less. Hence better efficiency for cruising with gearboxes.

The concept (hybrid) for power peaking with electric augmentation is a winner, however. Seems all the automakers have a hybrid somewhere. Good ideas, hybrids will probably be in all our futures given time. I just wonder what the maintenance costs will be.

Regards,
BigMoose

 

well, how would u start the motor? and how would u have any of the electricals work with the engine being off?

 

OK, so maybe one standard car battery. Dont make me bust out the cold fusion on you fools!

 

moose there has a point, trains take a loooong time to get going, cawse they have to get all that mas a-rollin.
but hey, that still might be a good idea! why dont you email honda's r&d?