Turning a TDI into a EREV?

[storx]

Could a TDI be used in this same situation but in a smaller pickup like maybe a Ranger or Tacoma??

I went to the track this past weekend to get out of the house and see my cousin race his bike, but between events there was an electric motorcycle class that ran on the track and after watching the race i went to check out the the bikes and ran across a really nifty setup for a DIESEL that blew my mind...

This guy took a 2008 Dodge Ram 2500 6.7L Diesel pickup and took the drive shaft out of the truck and installed an Electric Motor coupled to the output of the Manual Transmission and another coupled to the Rearend of the truck.. Between the frame he had an aluminum box containing the batteries, which he claimed he could get 41 miles of range out of before they were dead...and their voltage matched the voltage of his bike... so between races instead of towing a electric generator to site, he idles his truck in 6th gear, thus turning the electric motor creating power to charge the batteries and such.. the battery bank is the same voltage as his bike battery setup, so he just connects a thick wire between the bike and his truck and the trucks full batteries dumps their charge into the depleted bike battery via DC to DC charging.. within a few minutes.. He leaves his truck idling between races to top off the charge on his trucks batteries via the electric motor powered by the diesel generator.. When the truck is idling around 800rpms.. connecting the bike to the truck makes the turbo spool up at 800rpms from the load of the electric motor.. making turbo noise out the exhaust..

He said he drives the truck to and from work during the week now all on EV since its within the 41 mile range, he also told me that on the highway he can pull off 26mpg with the truck due to the low rpms of the motor and constant load...He has solar electric at his house and he wired up his batteries to a separate plug that matches the voltage of his truck bank also so he can charge it DC to DC to negate the loss from equipment and allow his truck to be an extension to his house backup power...

He uses the truck to tow the bike to the track in the back of the truck.. so the electric motors seem to be strong enough to tow a few hundred pounds over the weight of the truck.. he said the back one was 450 torque and the front one was 280 torque

So this guy is getting better than stock MPG with the truck when using diesel.. saving money
Saving the cost of 41 miles a day in fuel to drive the truck...saving money
Saving the cost of owning and running a secondary electric generator at the track... saving money
Saving the cost of electric to power his house and truck, by having solar panels and solar bank at home.. saving money..
This idea just seems to be a win-win from all directions.. why don't car and truck manufactures not utilize this type of setup in current vehicles??
(Image is not the truck, but similar model... i was so in the moment talking to the guy i totally forgot to take a picture of it)

 

[storx]

The GM Volt is only getting 35-40 miles per batter charge. Now the volt doesn't use the top or bottom 20%. So what kind of batteries and what size is this guy using to move a 6000lb truck 40 miles?

Side note. So Volt owners have figured out how to adapt the Volt to be used as a emergency generator for their house.

I am unsure.. but there is a TON of room under the truck.. once you remove the 6 foot long drive shaft.. but batteries are pretty powerful.. those electric bikes went like 20-25 laps around the course at nearly full throttle on a battery size of about the size of a school backpack...

Plus.. After reading into EV's and such..the battery in the Tesla Model S very small powering a 5000+ lb vehicle down the road nearly 300 miles.. and when you look at the pictures of the battery pack torn apart.. the actual batteries take up 44 inches x 35 inches x 4 inches tall.. the rest of the space that the battery back has is protection barrier for bottoming out... So if you reconfigure that out.. that near 300mile range can easily fit under the truck in between the frame rails..

I asked the guy why he didnt just remove the transmission from the truck to have more room for batteries.. but he said the 6th gear allows him to get more amps out of the motor at idle speed and he was unsure how long the setup would last.. so he didn't want to make it so he couldn't change it back if it all failed on him.. so the drive shaft is sitting at home still..

Pic to give an idea..

 

[storx]

It's a 900lb battery with a 30K price tag.


"To see 300 miles range you need to change from Rated to Idea range displayed. From the Owner's Manual (Page 41):

9. Range estimate
The estimated range based on the amount of energy remaining in the Battery. You can specify how you want to display range by touching Controls > Settings > Units & Format > Range Display and choosing:
• Rated - based on EPA testing.
• Ideal - assumes ideal driving conditions based on driving at a steady speed of 55 mph (89 km/h) on a flat road, and using no additional energy (seat heaters, air conditioning, etc)."

No, i was just talking about it as an example and it wouldnt cost 30k, if you read the forum posting about the dissection of the Tesla Model S battery... they said it had the following...
7350 x Panasonic 3.4 Ah 18650 cells

When the guy took down the model number of the cell and called around to see if they can be purchased in bulk... he posted a phone number to a company that would sell him 10,000 of these exact Panasonic batteries for $3,799 dollars, which puts the batteries themselves being less than $2800 bucks... due to cheaper price on the cells the higher the bulk amount purchased..... in reality i would guess that it cost them less than $1500 to purchase these cells from Panasonic...

 

[03_01_TDI]

That's the price Telsa is saying. They do offer a prepay price of 12k.

 

[nord]

I hate to throw cold water on this but...

The first thing needing to be understood is that by doing what this gentleman claims, he's pretty much clipped the wings of this truck. Allow me to explain:

No mention was made of any provision for four wheel drive. It's not that fwd can't work in this configuration, it's just that the load normally divided between front and rear axles would in the main be transferred to the front under diesel power. Probably not a good plan considering no direct connection to the rear axle.

Then the diesel engine. About the worst possible treatment for the Cummins is extended idle time. These engines were basically designed as stationary prime movers and expected to run for long durations at high torque, moderate rpm's, and full load. He's asking it to do the exact opposite.

The electric motors would appear to defeat the purpose of the diesel engine when it comes to the torque department and also overall horsepower. There's no way this configuration could match the performance of the truck in conventional configuration.

Now it's time to consider the use and transfer of energy...

The configuration as described removes none of the energy absorbing components found in the conventional drivetrain. The fact is that it's just the opposite. Without going deeply into detail the generating motor and the driving motor both produce heat and are inefficient. The wiring no matter how efficient is also guilty of a loss. Batteries do not and cannot return 100% of the energy used to charge them.

Couple the losses involved in the converted system with the fact that none of the normal losses were addressed and there cannot possibly be a gain in efficiency. All that's been done is to make the truck less efficient overall while claiming the opposite.

Think of the overall picture. Lets give the claimant his due and say the truck will travel the claimed 41 miles on battery power alone. Might I ask just how little things like power steering, a/c, accessories, and perhaps the hydraulic brakes might be kept working while moving under just battery power?

Then a question of energy and the transfer of such. Unless I miss the mark it would seem that somehow the batteries are being charged at greater efficiency than could ever be possible. If we give the diesel and associated components back to the the first electric motor a value of about 30% efficiency, then couple to an inefficient electrical system, please explain how there ever could be a gain? There can't!

What I'm getting at is that it takes a certain (and greater) amount of energy to run a generator and store a lesser amount of energy in a battery bank. Once this energy is stored in the battery bank there's yet another loss as it's directed to power an electric motor. Whether the claimed 41 miles on battery alone is true or not isn't in the least relevant. Only the total amount of energy required to accomplish this task bears consideration.

Lets look at the diesel locomotive before we go further. In this type of configuration we have a prime mover attached to an alternator. The alternator through electrical switching gear powers a series of traction motors which in turn power the driving wheels. In this configuration there is no mechanical transmission thereby eliminating a major inefficiency. Further, the prime mover is always allowed to run at an optimum power setting. And while very good at what it does, the diesel locomotive is still very inefficient. And the truck as described even less so!

So now to some particulars:

You may or may not realize that the Dodge setup on a manual transmission usually has a PTO provision. While I consider this whole project an exercise in futility, would it not have made better sense to drive an auxiliary generator/alternator/motor here and leave the driveshaft in place?

Since we already know that the electric motor can be used as a generator, why not use it as such? Now we've left the drivetrain intact and only made minor modifications to the vehicle. Of course we've solved nothing as far as accessory needs when supposedly running under electric power, added weight and expense to the vehicle, and have ourselves a less efficient vehicle than when we began the project.

Apply the above to a front wheel drive system and it gets all the more complicated. So substitute the motor and transmission for batteries and an electric motor? Or perhaps an electric motor on all wheels? Then remove the brakes because we can use the motors for such and apply the energy generated to charge our battery. But puzzle me this... Where do we install our prime mover in this affair?

But on a positive note we'll be able to charge an electric motorcycle. Of course so will a portable genset without nearly the expense or trouble, but that wasn't the question.

 

[Dirtracr95]

Those cummins trucks with intake/exhaust/tune can do 26mpg on the highway especially if manual trans.

Nord makes awesome points.

I was just going to say it was probably just a PTO. Ive installed plenty PTOs on those trucks. An electric motor would not have enough balls to propel an 8000 lbs truck from a dead stop without some type of additional gear reduction.

Now if you wanted to make a hybrid truck that would be alot easier, cheaper and practical.
You could take a 2wd truck put a 4wd trans/transfer case in it and hook the electric motor upto the flange for the front driveshaft. You would have to steal all the wiring and computers and such from a hybrid somehow make them work with your truck.

 

[drewkeen]

he's pretty much clipped the wings of this truck. Allow me to explain:

No mention was made of any provision for four wheel drive. It's not that fwd can't work in this configuration, it's just that the load normally divided between front and rear axles would in the main be transferred to the front under diesel power. Probably not a good plan considering no direct connection to the rear axle.

You do realize that a lot of these trucks are 2wd to begin with right?

If you are just doing highway towing then 4wd is a waste of money, fuel and wear and tear on extra, unnecessary parts.

 

[nord]

And you, sir, realize that it really makes no difference, except that a 2WD conversion is even more improbable in that as described it would force the truck to be totally motivated by the electric motor.

Please tell me you don't really believe that substituting an electric motor of even moderate torque and horsepower, adding sufficient batteries, and basically using the diesel to twist a generator/alternator would somehow be an improvement over OEM. It's not! This especially when considering the overall energy requirements of a fossil-fueled vehicle.

When technology advances to the point where fuel cells or some technology presently unknown to me reaches the point of affordability, then perhaps electric power for heavier over-the-road vehicles will become practical. I'll include battery technology here with the caveat that it must be understood that whatever source we select must be able to deliver equivalent energy and power over similar distances allowed by conventional vehicles today.

Look at the problem this way... Our present internal combustion engines average about 30% efficiency. Gasoline less and diesel a bit more. By the time the power they produce gets to the ground we'll be somewhere in the teens as far as efficiency. In other words if we assign 20% efficiency to a vehicle it takes a total of five gallons of fuel to do what one gallon would do at 100% efficiency.

If we could convert fuel into work at anything above that 20% on a sustained and equal basis to a conventional vehicle, then we'd be ahead of the game. So far we can't. The little Prius or Volt is a compromise at best. In some situations they work fairly well... That is until you consider their actual cost and not just the fuel involved.

Bottom line here is that it takes a set amount of energy to do a particular job. In addition to the basic energy required we have to add the energy required to run the machine we're using for performing this job. Since the former requirement is not negotiable, our only possible savings will be found in the efficiency of our machinery. The plan as laid out in OP is a red herring... Totally bogus.

 

[storx]

I think a lot of the responses are overlooking the real facts of this setup and not understanding that it CAN be done and IS more efficient if done correctly.. I dont have a lot of answers in regards to the truck itself as its not mine.. but the setup worked.. as i watched it in action and looked under it to see that there was in deed no longer a driveshaft between the tranny and the rear..

The point of the build for this guy was to have a way to charge his bike within a reasonably quick time frame or be required to take the bike apart to remove the batteries and swap them between races.. most of the other bikes on site used this method or they had a battery box on their trailer that was used to store the charge from the generator between races.. either way REQUIRED the purchasing of extra batteries... since charging that size of EV batteries with just an portable generator takes a lot of time due to the limitations on these devices and also the fact that most generators have very dirty voltage output.. so he did this to his truck to have clean energy....

In regards to the towing question, yes i agree he couldnt tow as much as he could with the diesel engine before.. but that wasnt the point of the build..

In regards to the driving with the brakes and stuff.. he did mentioned that he idles the truck in neutral for A/C... so i am guessing this is how he is able to use all those items.. but even then diesel engines use very minimal amounts of fuel at idle compared to gasser counterparts..

In regards to the leaving it to idle for long periods of time, when i was at the track and he hooked the bike battery up to the truck so the batteries would DC charge the bike, the electric motor on the tranny pulled more of a load since the batteries were no longer topped off and you heard the diesel engine change exhaust tone and the turbo spooled up as you could hear it from the exhaust.. so i would assume that this would be the exact same thing as driving it on the highway in 6th at a very low rpms.......

There are multiple vehicles that are popping up after doing some research that use this type of technology and they are doing it successfully.. the chevy volt uses this method and achieves BETTER mpg results on fuelly than the chevy spark does with the exact same engine in a vehicle at nearly half the weight of the volt.. its all because an engine is much more effecient at a set rpm than it is reving up and down constantly.. the engine control module can adjust fueling trims to achieve better MPG when the rpms are constant, thus netting much better results..

A truck that matches the above concept somewhat would be the VIA truck.. i came across it and that truck achieves better MPG than the same truck with the same engine at 2k lbs lighter..

 

[saGhost]

Could a TDI be used in this same situation but in a smaller pickup like maybe a Ranger or Tacoma??

A modern 2.0 TDI in a properly designed EREV application would probably be plenty of power for a full size pickup - I doubt they use more than about 60 kW (80 hp) to run down the road at 75+ (And a well designed EREV doesn't need the engine to do more than match the continuous steady state load.)

This guy took a 2008 Dodge Ram 2500 6.7L Diesel pickup and took the drive shaft out of the truck and installed an Electric Motor coupled to the output of the Manual Transmission and another coupled to the Rearend of the truck.. Between the frame he had an aluminum box containing the batteries, which he claimed he could get 41 miles of range out of before they were dead...and their voltage matched the voltage of his bike... so between races instead of towing a electric generator to site, he idles his truck in 6th gear, thus turning the electric motor creating power to charge the batteries and such.. the battery bank is the same voltage as his bike battery setup, so he just connects a thick wire between the bike and his truck and the trucks full batteries dumps their charge into the depleted bike battery via DC to DC charging.. within a few minutes.. He leaves his truck idling between races to top off the charge on his trucks batteries via the electric motor powered by the diesel generator.. When the truck is idling around 800rpms.. connecting the bike to the truck makes the turbo spool up at 800rpms from the load of the electric motor.. making turbo noise out the exhaust..

He said he drives the truck to and from work during the week now all on EV since its within the 41 mile range, he also told me that on the highway he can pull off 26mpg with the truck due to the low rpms of the motor and constant load...He has solar electric at his house and he wired up his batteries to a separate plug that matches the voltage of his truck bank also so he can charge it DC to DC to negate the loss from equipment and allow his truck to be an extension to his house backup power...

He uses the truck to tow the bike to the track in the back of the truck.. so the electric motors seem to be strong enough to tow a few hundred pounds over the weight of the truck.. he said the back one was 450 torque and the front one was 280 torque

So this guy is getting better than stock MPG with the truck when using diesel.. saving money
Saving the cost of 41 miles a day in fuel to drive the truck...saving money
Saving the cost of owning and running a secondary electric generator at the track... saving money
Saving the cost of electric to power his house and truck, by having solar panels and solar bank at home.. saving money..
This idea just seems to be a win-win from all directions.. why don't car and truck manufactures not utilize this type of setup in current vehicles??

It isn't as easy as it sounds in his description - and you have to consider the cost of the new systems. It is absolutely possible to do what he said, and you would save money on all the aspects described - but you'd pay twice as much for the truck (and solar panels,) so it'd take a long time to make your money back.

Electric motors to match the truck's original performance are possible - but that's not what he has from the description. The rear motor puts out 450 ft-lbs of torque, and is hooked directly to the differential? Assuming he has the taller of the two axle ratios, that gives him (450*3.73) about 1680 ft-lbs at the rear axle - even in 6th gear the stock truck can put more power down (3.73*.74*660 = 1821 ft-lbs.)

In first gear, the stock truck can produce some 14,600 ft-lbs at the rear axle - almost 10x as much. So acceleration from a stop won't be impressive, even without a load in tow. The motors add weight, the batteries add weight, and the accessories will be a challenge.

Almost all engines are most efficient at moderate RPMs and nearly full throttle; it might be possible for him to improve the truck's fuel economy by cycling the engine on the freeway - running it harder to charge the battery and drive the truck for a while, then running electric for a while (though it means incurring conversion losses for half the power both directions and charging losses, so how well it works will depend on the details of the engine and loading scenario) - but that's not what he describes doing.

I'm also worried about all of these uncontrolled DC-DC charging events. Lithium batteries are not tolerant of over-charging or over-discharging, and with the batteries hard wired to a DC source there's no protection against that. Hooking a fully charged pack up to a discharged pack of the same nominal voltage directly is a recipe for massive current flows, likely leading to overheating of both batteries and the wiring. Also not good for longevity (nothing kills Lithium batteries faster than high temperatures.)

For a truck that does pretty much everything he says he can do, have a look at VIA motors - and be sure to note the fleet only ~$79k price tag. As Tesla and others drive the price of batteries and high power motors and electronics down, this will become much more practical, but right now it involves sacrifices and a whole lot of money (though it does save money in day today operation.)
Walter

 

[GoFaster]

If you have a combustion engine, "series hybrid" is not the way to go. It adds a bunch of charge/discharge losses that are not present if you just use mechanical drive. There's good reason why a Prius transmits most of the drive power mechanically during highway cruise. There's good reason why the Volt (and the new Accord hybrid) couple the engine mechanically.

That's not to say you can't combine this with a plug-in electric system - but the engine is better off driving the wheels mechanically.

The electric racing motorcycles are pointless if you are going to use a combustion engine to charge the batteries ...

Don't get me started on the outrageous claims that VIA Motors has made for their conversions. "Not Gonna Happen". A great big heavy unaerodynamic truck is going to take lots of energy to push through the wind and over hills.

The Chevy Volt does not get fantastic mileage when operating in gasoline-engine mode.

 

[nord]

Let's review...

We're starting with a 7500 pound truck here. It's built for what the average user considers heavy hauling and generally demanding use. Then we're going to "improve" the truck by removing the connection between a 300+ horsepower diesel capable of torque almost beyond belief with what amounts to an alternator, a battery pack, and an electric drive motor. So the net reduction in weight is one driveshaft, but this is offset by orders of magnitude in the hardware added.

Let's for a moment consider energy requirements. As stated above the diesel engine must be kept running in order to power the necessary accessories. Air conditioning alone soaks up about 6 hp. Then the hydraulics and whatever else as may be required. The total is by no means inconsiderable. Then, of course, the "alternator" which provides current to the battery pack and drive motor. We do agree, don't we, that a given task under given conditions using a machine of a certain configuration needs (and will use) a definable amount of energy plus the energy needed to compensate for inefficiency?

The configuration as described may be looked at as a stream or river trapped by a reservoir. The stored water then being dropped through turbines to generate electricity. In this case the water source is limited to the capacity of the alternator, the storage limited to battery capacity, and the output limited to the rating of what for all purposes is the traction motor. Further, if I understand correctly, the alternator capacity is less than that of the traction motor.

In a nutshell you're describing not a huge river, but a stream flowing into a reservoir of limited size. You're then describing what amounts to dropping the contents of this reservoir into a turbine which will consume considerably more water than is flowing into the reservoir. In this entire process there's been absolutely nothing done to increase mechanical efficiency, weight has been added, and the (stream) diesel can never be shut down.

Given the above it becomes a simple matter of timing as to the claims made. Basically this amounts to the time it takes to run the batteries dry. Once this point is reached the alternator input will be incapable of matching the total requirements of the traction motor. To put it another way the traction motor cannot output more energy than is being input. In essence the batteries provide only a buffer between total input and total output until they discharge. So the entire question becomes a balancing act of limiting energy needs to less than required for vehicle motivation over time and distance.

Now to an unbreakable law of nature... You can't get more energy out than is put in. The diesel engine will always be be soaking up energy in the form of heat, parasitic losses, and mechanical inefficiency. Running a transmission will add further mechanical losses. This not to begin to account for the losses incurred by the electrical conversion. Thus, the bottom line here is that all of the energy needed must come from the diesel fuel which is converted into energy by the engine. You may somehow believe that the theory about increased efficiency at an "idle" or constant speed makes all the difference. I'm not in that camp. I doesn't, it can't, and it never will.

What you're seeing is a different use of the available energy over the short term. This would tend to make it appear that there somehow has been an increase in efficiency. But once you've drained the reservoir, then what happens? Add it up... The "alternator" produces less output than meets the needs of the traction motor under any demanding conditions. Batteries need to be charged. The Cummins up front has to meet all those needs, plus account for its own normal losses. And this doesn't account for the losses associated with the conversion electrics.

So in the process of "efficiency" the truck has been emasculated, weight has been increased, and none of the energy-robbing mechanical components removed. Oh... And the Cummins cannot be shut down because accessories still need to be powered, along with the conversion charging system to try to keep the batteries topped off.

All in all a great story. May I suggest a further conversion? Add a water tank and use the alternator output to hydrolyze the H2O. Route the product (Browns Gas) into the Cummins and turn off the diesel fuel. Add a gallon or so of water from time to time and sell the excess electricity back to the utility company.

Or... Brush up on physics in matter of the conversion of energy or potential energy into actual work.

 

[nate0031]

You could see increases in efficiency due to having the engine at a favorable RPM at all times. This would really only benefit you in a stop/start situation though, as that is where the engine is running least efficient, running through all the gears. If you're properly geared for the speed you're running, you simply can't beat a direct mechanical drive for efficiency. Especially by converting mechanical energy to electric, and back again.

You could supplant some of the required energy with another source, giving you higher miles per gallon of diesel, but the net energy consumption is the same, having been displaced at best. One thing that would crack me up is when people using propane injection on diesel pickups boast of their mileage gains. You didn't magically increase engine efficiency, you supplied another source of fuel. I'd sure hope you're using less diesel. At best, you net a gain if your secondary energy source cost less than the same energy as supplied by diesel. I haven't run the numbers. Maybe propane is cheaper per BTU and that's what the rage is, that and the power.

For a setup like storx describes, your best option would be to use a smaller diesel like some have mentioned. Figure out what your load will be, how much energy you need. Then get the BSFC charts for available engines in that range and pick the one that lands you in the most efficient plateau given the energy you need. An engine is typically most efficient running at full throttle near its peak torque, thus the Cummins is way over-sized, as it doesn't take nearly its peak power to move a stock truck plus ~2,000 pounds of add-ons. A setup such as this just isn't ideal though, as the load a car/truck sees is so dynamic. You are either under powered for stop and go traffic/large loads, or over powered for steady state highway cruising/no loads. This is why this setup is typically preferred for trains etc, where you have consistent load/speed conditions.

No doubts there are electric motors capable of moving that truck well though, and hauling a massive load along with it. Motors aren't the issue, the power density of our batteries is. My RC helicopter has a motor about an inch in diameter and maybe one and a half long. It puts out .6 horsepower and has constant torque from 1-30,000 RPM's. That's not much horsepower, but given its size, and the size of the ESC that runs it, it's pretty stout. It's not even a high end motor. The problem is, the battery that runs the whole shebang is twice the size of the motor and ESC combined, and yet only lasts for 10 minutes. It charges quickly, a half hour if I charge at 2C, but I usually do an hour at 1C. Still way longer than pouring fuel in a tank. Another example, I worked on an electric race car in school. It was powered by 28 deep cycle batteries, and had a 120 HP, 3 phase, oil cooled motor. The motor was about a foot and a half long and ten inches in diameter. It was connected to a 4 speed gearbox. I hardly ever used anything but 2nd gear and reverse though, as it just spins faster and faster and faster. You get pushed back in the seat the moment you hit the accelerator and just go. That motor sounded awesome as it spun up. At full throttle, bus voltage dropped to about 285 and current draw was about 350 amps.

I'm not discounting what the guy did, just saying his setup isn't ideal. More power to him for thinking outside the box though.