The problem with series hybrids

[roflwaffle]

IIRC the biggest issue w/ hydraulic hybrids was cost. They can improve FE in the city by ~40% or so, but I don't think that's worth a $3000-$4000 premium versus a BE system that improves city FE by ~30%.

[user removed]

Originally Posted by roflwaffle

IIRC the biggest issue w/ hydraulic hybrids was cost. They can improve FE in the city by ~40% or so, but I don't think that's worth a $3000-$4000 premium versus a BE system that improves city FE by ~30%.

You should check out the link, the improvement was 100%.

Mass produced accumulators would not be as expensive as the previously mentioned power train components that would no longer be necessary.

The design I propose would be no more expensive than the brake components it would replace.

In fact if you dedicate the thought process to a hydraulic hybrid, you could incorporate structural components of the unibody as accumulators. An example would be the front crossmember that supports the suspension components. A perfect place for an acumulator.

When understood properly the cost would be LESS than a conventional powertrain and the total vehicle parts count about 25% lower than conventional with a corresponding reduction in total vehicle cost.

Also life expectancy would be superior to anything made today, whether conventional, hybrid, or electric.

Per wheel unit manufacturing cost would be about $100 each. You would never have to do another brake job in 500k miles, and by then most of the rest of the car would be disintegrating.

Imagine a Pontiac solstice (hydro formed tubular frame) where the frame itself was the accumulator and low pressure storage, with suspension components doing double duty as hydraulic conduits.

Add 4 wheel drive with good traction tires. Acceleration at the limits of adhesion of all 4 wheels simultaneously.

regards
Mech

[dcb]

Originally Posted by NeilBlanchard

A serial / series hybrid is much more efficient than an ICE -- because the electric motor is so much more efficient than the ICE. It is about 85-90% vs 5-20%. And the clutch and transmission only lower the ICE's efficiency.

ug, the series hybrid has BOTH an ICE and a motor AND a generator to boot.

Originally Posted by NeilBlanchard

The serial hybrid motor has a fixed load, at a fixed torque.

and I can keep my stickshift within 90% of peak load, so? if we get to assume a bunch of technology updates then I get a direct drive/no extraneous meshing top gear for my hiway (range extended) vehicle.

Originally Posted by NeilBlanchard

We have several known examples of serial hybrids: diesel/electric trains are serial hybrids -- I wonder how it is they can move a ton well over 400 miles on just one gallon of diesel?

dude, it isn't a hybrid, it IS diesel, it runs steel wheels on steel rails (low RR) and is very aerodynamic. They don't make 5 speed transmissions big enough to propel a train is why the drivetrain is like that.

Originally Posted by NeilBlanchard

and it got ~80mpg in charging mode.

Neil, c'mon now, you are venturing into overunity land here. They are playing serious word games.
"An on-board petrol engined generator offers enough electrons to run continuously at motorway speeds without depleting the battery"
"After delivering the energy to the battery system the mileage translates to around 80mpg "

I think they mean a wall-charged battery in combination with the 250, though the 80mpg part is very unclear. but with a word like "translates" sitting there, it is so not clear what they are trying to say. Remember how popular gm was when they claimed 230mpg for the volt? And everyone called BS on it?

The question here is what is the most efficient use of petrol, and I think the inefficiencies of this petrol setup are being masked by throwing in other variables like electric wall power. If you had to sit in the driveway and recharge the battery with the engine to where it was before you left, you would not see 80mpg, you would be lucky to see 30mpg. Obviously this would be stupid to do with a wall outlet there, but lets at least try to compare petrol use to petrol use?

To me it is obvious that electric has short range covered (say 40 mile radius), and that is %90 of a typical vehicles life. if you are serious about being efficient with the petrol then why not save it for a purpose built hiway device where most batteries cannot reach? In fact you probably already have a working petrol vehicle in your garage right now, and could cut down petrol use very dramatically by adding a clean and simple EV for commuting, etc.

But lets not hide inefficient petrol use behind high hp numbers, parroted misconceptions, deceitful comparisons, or other consumer tricks.

[NeilBlanchard]

Hi,

Originally Posted by dcb

there are many losses to consider:

engine to generator
generator to controller
controller to motor
generator to charger
charger to battery
battery to motor
transmission/wheels


whereas a small gasser can use
engine to transmission/wheels

You've got some extra steps in there; and actually there are two ways to do serial hybrids. One is like the Volt and diesel/electric trains:

engine to generator
generator to controller
controller to motor
motor to reduction gears/wheels

The Volt has a battery that it uses first, and then if it is needed it goes into serial mode, with the ICE varying in speed to generate enough to power the electric motor. I don't think this is as good in a car as it is in a train, because a car has much more varied demands; whereas a train has so much mass, it only has two power modes (accelerate and cruise) and these are in "ultra slow motion" compared to a car.

The second uses a plug-in battery to start with and then the ICE recharges it, and then the ICE shuts off. So, the list is:

engine to generator
generator to charger
charger to battery
battery to motor
motor to reduction gears/wheels

And your ICE list is too short:

engine to clutch/torque converter
clutch/ torque converter to transmission
transmission to wheels

And the length of the list doesn't matter -- it's the efficiencies/losses for each.

A plug-in serial hybrid has a battery-only range, and for this mode it is much better than the ICE: a gallon of gas = ~33kWh of electricity (IIRC) so, this means an MPGe of 100 is about the worst you can get in an electric car. From the Plug In America FAQ:

EVs are the most efficient cars on the road:
Toyota RAV4 EV: 887 BTU/mile
Toyota Prius: 2250 BTU/mile
Toyota RAV4 Gas: 4423 BTU/mile
RAV4 EV rated 112 MPG equivalent.
Gas Mileage, greenhouse gas emissions, air pollutant emissions and safety ratings of new and used alternative fuel vehicles

The gas version of the RAV4 is almost 5X worse FE than the RAV4 EV.

The ICE in a serial hybrid by definition is going to be at peak efficiency ALL THE TIME. Also, by definition, it will be a much smaller, lighter, engine, and it will have smaller and lighter cooling system and fuel tank than an ICE powered car. Lets use the Mini as an example: 1.6L (I think?) vs the 250cc speaks for itself. The ICE Mini can probably get 40mpg (it is EPA 24/33), so a 10 gallon tank goes 400 miles. The Mini hybrid already gets 200-250 miles on it's batteries alone, and at 80mpg in charging mode, it only needs 2.5 gallons to get to 400 miles total.

So, the Mini Cooper gets 40mpg and uses 10 gallons of gas.

The Mini serial hybrid uses the electricity in it battery (probably about like the Tesla's?) of about 42kWh (80% of the 53kWh capacity) = 1.2727 gallons = 157MPGe for the first 200 miles, and then 80mpg and 2.5 gallons of gasoline for the second 200 miles. That is 118MPGe overall.

It's not even close.

And the Mini serial hybrid has 640HP and four wheel drive...

[NeilBlanchard]

Trains are diesel/electric, dude:

Diesel locomotive - Wikipedia, the free encyclopedia

In a Diesel-electric locomotive the Diesel engine drives an electrical generator whose output provides power to the traction motors. There is no mechanical connection between the engine and the wheels.

And they AVERAGE 436 miles / gallon / ton

http://www.factcheck.org/askfactchec...ly_move_a.html

Sure, they've got ultra low rolling resistance, but I very much doubt they are very aerodynamic.

[dcb]

Dude, that electricity does not get to your wall % 100 efficiency, which is why it needs to leave the discussion, as we will not agree on a fair conversion factor.

so those mpge numbers are pretty much bogus as are the wishful thinking of efficiency. I don't care about wall power for this discussion, again it isn't relevant. You HAVE to compare apples to apples, i.e. petrol use to petrol use, without getting out and pushing in one case. The point is to make best use of the petrol to minimize its consumption, not hide behind manufactured complications.

and a 640hp anything is a pinky wave.

[dcb]

Originally Posted by NeilBlanchard

Trains are diesel/electric, dude:

Diesel locomotive - Wikipedia, the free encyclopedia

lol, that still doesn't make them hybrids, oh keeper of definitions

"A hybrid vehicle is a vehicle that uses two or more distinct power sources to move the vehicle"

[NeilBlanchard]

The gasoline has to be drilled, transported, refined, transported again -- I'm not dealing with well-to-wheel efficiency. I am comparing electricity to gasoline equivalency.

Listen: a serial hybrid is an EV that has a way to charge itself as it drives. Of course that has to be included! It is part of the system and it is THE REASON you would design the car -- and you certainly can drive it on the battery alone if don't go beyond the battery's range. And even if you do leave it out, the serial hybrid still beats an ICE powered car.

[roflwaffle]

Originally Posted by Old Mechanic

You should check out the link, the improvement was 100%.

Mass produced accumulators would not be as expensive as the previously mentioned power train components that would no longer be necessary.

The design I propose would be no more expensive than the brake components it would replace.

In fact if you dedicate the thought process to a hydraulic hybrid, you could incorporate structural components of the unibody as accumulators. An example would be the front crossmember that supports the suspension components. A perfect place for an acumulator.

When understood properly the cost would be LESS than a conventional powertrain and the total vehicle parts count about 25% lower than conventional with a corresponding reduction in total vehicle cost.

Also life expectancy would be superior to anything made today, whether conventional, hybrid, or electric.

Per wheel unit manufacturing cost would be about $100 each. You would never have to do another brake job in 500k miles, and by then most of the rest of the car would be disintegrating.

Imagine a Pontiac solstice (hydro formed tubular frame) where the frame itself was the accumulator and low pressure storage, with suspension components doing double duty as hydraulic conduits.

Add 4 wheel drive with good traction tires. Acceleration at the limits of adhesion of all 4 wheels simultaneously.

regards
Mech

There won't be a 100% improvement for a ~$3000-$4000 premium over a BE hybrid AFAIK. The BE hybrids have already proven to be successful. UPS ordered 200 of 'em, so the proof is in the pudding IMO. I've been hearing about hydraulic hybrids since 2006, and UPS is supposedly testing them too, but they haven't caught on like the BEs have AFAIK. Time will tell I suppose, but if UPS ordered 200 BE hybrids after testing, but no hydraulic hybrids after testing, I have a feeling the BE hybrid is a better deal. Barring of course UPS not being done w/ the hydraulic hybrids or something else preventing them from getting good data to compare both.

[NeilBlanchard]

The Volt is a serial hybrid that runs in virtually the same way that diesel/electric train locomotives do -- they are both serial hybrids.

Facts are facts.

"A hybrid vehicle is a vehicle that uses two or more distinct power sources to move the vehicle"

This is not a correct definition for all hybrids; it might be right for parallel hybrids, but not serial hybrids which is what we are discussing.

"A hybrid uses two or more types of motors in some combination to move the vehicle" is more accurate.

A serial hybrid uses one motor (electric or hydraulic) exclusively to move the vehicle, and the other motor (ICE usually) to power the traction motor. Batteries and/or supercapacitors, or hydraulic pressure tanks are also involved; acting as buffers/storage of the power. They are part of the system.

The only reason to use a serial hybrid in a car is to start with a plug-in EV, and give it a longer range. An EV is far more efficient than an ICE, and you can have regenerative braking, and as mentioned earlier, the ICE can be made much more efficient because it does not need to put out as much peak torque and it doesn't need a broad power band, and so it can be finely tuned to one RPM.