The problem with series hybrids

[dcb]

ok, I didn't put it together that you wanted to use your flywheel thing as wheel motors and engine pumps.

Patents, blech, don't want to take this thread there, as bad or worse as they are good. If you are interested in money, try a patent, if you want to make the world a better place, share what you know.

But your specific agenda aside, here is some hydraulic vs electric efficiency picks I found. I assume this is just for motor mode, so double the losses for comparison to peak efficiency of a parallel hybrid.




according to the pics, you can cover a much wider range of conditions at higher efficiency with hydraulic transmission.


I did see one road vehicle that has a hydrostatic transmission
2009 Honda DN-01 - Specifications - Honda.com
though it seems a little piggy @ ~600 lbs.
wikipedia lists it at 48mpg,

Its 5 speed cousin, the nt700v, is listed at 50mpg, 562 lbs, and $4500 less per the honda site.

[roflwaffle]

Originally Posted by Old Mechanic

Regeneration of electric hybrids-pitiful compared to hydraulic

You're kidding, right? If you take the same weight carbon fiber accumulator compared to an old NiMH battery pack, the accumulator can only store about a ninth of what the battery pack can store. As bad as batteries are in terms of energy density, the better accumulators are about ten times worse.

Originally Posted by Old Mechanic

Life expectancy of electric hybrids-pitiful compared to hydraulic

That's likely true if we have a situation where a vehicle is stopping way more than even a cab. If a garbage truck stops ten times more often than a taxi, then a battery pack would only last 34,000 miles instead of 340,000 miles. In that context a HH is a good idea. W/ a garbage truck, the extra weight from the system isn't an issue, and all the stops are from roughly the same speed, so the accumulator doesn't have to deal with capturing energy from higher speed stops too. KE goes according to speed squared, so if a 240lb high pressure carbon fiber accumulator can only capture ~1/5th of the energy a 120lb battery pack can, then it has to be sized properly. For a car, this means the acumulator will have to be very big to capture the same amount of energy a battery pack can, or else it will only be able to capture a small fraction of what the battery pack can if it's the same size. Also, a 300k lifespan isn't an issue because cars tend to get junked around 150k on average. HD vehicles w/ many stops/starts otoh can see a benefit from greater lifespan like I mentioned before.

Originally Posted by Old Mechanic

Retained value of electric hybrids compared to conventional
Pitiful
Compare the resale value of a 2003 Corolla to a 2003 Prius, a cost you choose to ignore in your cost comparison.

Are you researching these statements before you make them? KBB indicates that the net loss is roughly the same between a 2003 and up Prius versus a comparable same year Corolla (LE), although that's technically not apples/apples since the Prius is larger and has more features. The Prius depreciates more but the Corolla costs more to fuel, the end result is that they are within a grand each other, w/ the Prius being slightly cheaper according to KBB's estimates regarding value.

Originally Posted by Old Mechanic

In 1971 in an attempt to make body shops look like they were making exorbitant profits the insurance company had a body shop estimate the cost of building a $3000 Chevy from scratch using new parts.

$17000 which demonstrates the flawed comparison between any assembly line built vehicle and one built outside of an assembly line.

Conversions versus factory mass production are false comparisons.

The EPA cost calculations included carbon fiber accumulators.

Unnecessary.

You can use the EPA's $7,000 figure if you like, the situation doesn't change much. HHs are still more expensive than HEVs. I suppose a ~240lb accumulator isn't needed, when we could forgo the ~80-90% weight reduction and use a much cheaper ~1000+lb accumulator. That's clearly practical. HH systems aren't common because they can't store a lot of energy compared to HEV systems. They'll also cost more given all the info I've seen from the EPA, and they're pushing them too. They make sense for large vehicles that will last a long time and stop/go in a predictable way over the same range of speeds.

Originally Posted by Old Mechanic

The EPA calculations also included a plea for a "new sheet of paper" in concepts and designs, which is exactly what my patented design constitutes. They could not possibly calculate the cost of something they did not know existed.

Obvious flawed comparisons.

No increase in vehicle weight.
No increase in overall vehicle cost, in fact a reduction in complexity and cost compared to a non hybrid.
No long term catastrophic battery or electric motor replacement costs that would equal or exceed the value of the vehicle not even considering the additional hybrid electric components.
Peak engine efficiency at all times without exception. You can not get that with gearing alone, even with an IVT.

After a year of research 8 students and a MIT doctor of engineering concluded that the design I developed was a cost effective alternative that could equal or exceed the efficiency of electric hybrids.

If you want energy density in a battery try the flywheel batteries developed by NASA for space exploration. Easily beats any chemical battery you will see in the next hundred years, but no one can afford the price.

$15,000 car with double conventional mileage, no brakes, no power train in the conventional sense, not even including the enormous additional complexity of an electric hybrid.

If you think you can build it, then don't sit here talking to the rest of the forums, put together a $1000 100mpg HH subcompact along the lines of Metro's/Ben's and all the other ~$1000 NEVs.

Originally Posted by Old Mechanic

The fact that electric hybrids are already in production does not mean they are the best solutions, that logic could be used to defeat any significant improvement in vehicular transportation over the last 100 years.

regards
Mech

All those improvements happened. HHs haven't happened. If they do, great, we get cheaper hybrids than HEVs, but that isn't what's happening. Manufacturers are going w/ HEVs for most consumer apps, and HHs are being offered in HD vehicles w/ frequent stops/starts for the reasons I've gone over before. Energy density in HD apps doesn't matter as much, lifespan is more important. In consumer apps, a longer lifespan doesn't matter much if it gets junked at ~$150k miles, and the poor energy density means a smaller vehicle will either have poor energy storage, weigh too much, or both compared to a HEV.

[NeilBlanchard]

So, the hydraulic system itself is wonderfully efficient -- but what about the power source? Is it an ICE? If so, is the ICE used only to charge the accumulator, or does it push fluid directly to the wheel motors? Is the ICE run at a constant RPM, or is it variable?

Because, mechanical transmissions are ~90-98% efficient, aren't they?

[user removed]

When I first conceived the basic design, it was for a variable displacement-compression diesel type engine. That started in August 2003. In early 2006 when I built a simple demo model, I reversed the piston and cylinder locations and realized it would make a good in wheel IVT. Back then there was very little knowledge or understanding of infinitely variable transmissions, much less anything that could go in the wheel.

Its much like the smart bomb did for the dumb bomb.

Take a hub on axle and add the variable stroke rotary piston component which allows the axle to become self propelled.

It really is the antithesis of the ever more complex power trains we see in vehicle development. It requires only very basic machining skills to build. With a cad operated machine it is a piece of cake.

By changing the "gear ratios" without range limitations you can always pick the best BSFC range of engine operation, until your average speed drops to the point where your operational tactic would switch to pulse and glide.

The engine operated pump can also serve as a starter to relight the engine for each accumulator recharge cycle.

Here is a thought. Would the total efficiency losses in this system be offset by the higher aero losses incurred in P&G when you pulse to say 50 MPH from 40 MPH and your aero losses rise by a factor of 2500/1600 (both speeds squared) versus the average of 45 MPH.

I still think the basic principle of hybrid design is that when you actually get it right then the vehicle will hypermile itself. With short term stored energy that can be applied at a consistent level of power to the wheels, this can be the programmed strategy of the displacement controller of the in wheel drives.

Maybe one day that will happen. The patent is not something that you can realistically ever expect you to really make a lot of money. Rudolf Diesel died poor, and a lot of other inventors never saw a return for their efforts in their lifetimes.

Ingo Valentin (Valentin Technologies) has been advocating this type of powertrain for over two decades. Many of his patents have expired. He is involved in the X prize competition. Another company called Lightning is also developing a hydraulic hybrid design. They are supposed to have a vehicle ready for X prize competition.

I'm Ok financially, and it gave me the time to spend on the effort. Injuries and age made it impossible for me to continue with manual labor full time, without using narcotic pain killers, something that makes me feel like I am a zombie.

I appreciate your effort to understand what I am trying to explain. The students at Va tech told me that it was not easy to understand without videos, or animations, or other visual aids, even for people with Engineering backgrounds.

I did not try for worldwide patent rights, so in that respect it becomes public knowledge and can be developed in other countries, but not patented in other countries, unless someone else can develop an improvement that passes the test of "novelty" and "not obvious to someone educated in the art".

The second criteria has such a wide interpretation that it is almost impossible to previal in any appeals process. In fact you are required to disclose anything you discover that could be used by the PO to reject your claim.

Thsi happened to me on the day that Michael Jackson and Farrah Fawcett died. Think it was the 23 or 24th of June 09.

Water Engines: Page 3

The design is so similar I was absolutely flored and thought my chances were zero of ever seeing a patent after 5 years and 30k.

I disclosed the information to the PO as required by law. Felt like I had been gut punched by a worlds heavyweight champ.

Didn't know until October that I had succeeded in getting the Patent. Even then, after the application was approved you still have a 6 month probation period which expires in 2months when they should actually issue the document.

Until then the jury is still out, but when you find an idea like this, the worst possible thing is to not try to get the knowledge out to people so they will understand there are other options. Some may be convinced it is greed driven, but there are many days I regret ever trying or beginning the process.

In the end the best reward may only be knowing I tried my dangdest to actually make a significant contribution, and that is a source of great satisfaction.

If you have a dream and you let it go, you never know what you could have done with it.

regards
Mech

[RobertSmalls]

This is around 5% of the energy density per kg of the NiMH battery in an Insight (kilowatt-second is a round-about way to say KJ). It can deliver that energy 20 times as fast as the Insight, which would make it attractive when highly efficient regenerative braking or rapid acceleration is required. It seems like a parallel hydraulic hybrid arrangement would be great for garbage trucks, city buses, and postal vehicles.

I require proper front/rear brakeforce distribution, and an outboard, cable-operated backup brake system on any car I own. I also need to be able to stop the car even if the battery / hydraulic accumulator is full. An inboard brake attached to a hydraulic motor can burn off extra energy for long descents and such, and conventional rear drums can be an emergency/parking brake.

The advantages of a tiny ICE in a parallel or series hybrid are plain, but one interesting limitation is hill climbing endurance. Once the battery runs out, you'll be climbing the hill on ICE alone, and 15HP won't propel a compact car very fast up a hill. Even 200lbs of hydraulic accumulator will only haul a Yaris-sized car up a 190ft ascent, assuming it starts at 100% state of charge. The electric hybrid's much higher energy density gives it an advantage here, where a stock Insight pack should be able to handle a 1000' ascent.

[RobertSmalls]

Originally Posted by dcb

Interestingly, there's a ~hobbit in the URL of this image.

Should I expect Honda's first-gen IMA system to behave like this as well? Hmm, this will give me something to think about the next time I use the IMA system.

[NeilBlanchard]

So, you are planning on using a diesel, and the hydraulics provide a variable RPM to the wheels. So, the engine RPM is varied with the throttle, and the hydraulics adjust the output speed ratio. And the hydraulics can be used to start the diesel -- what if there is no pressure available?

Can it glide? (In "neutral"?)

[user removed]

Guys

Here is the comparison of regenerative efficiencies.

You will never get the electric system to the level of efficiency to allow P&G of the engine using the electric option.

It applies universally to the vehicle, the non reversible power source (fuel stored and consumed) is not the point.

This concerns regenerated energy (recovered and reapplied) and pulse and glide strategies that apply to a vehicle regardless of the fuel supply or its origin.

Good night, talk at y'all later tomorrow evening.

The comparison is 10 years old, and the hydraulic option has improved by about 10 %, not sure about the electric option but it has not improved enough to make a real difference.

regards
Mech

[dcb]

Neil, Mech is probably "planning" on using his own engine design as the powerplant, connected to another one configured as a hydraulic pump, and one on each wheel.
http://ecomodder.com/forum/showthrea...ign-11517.html

Which, it should be noted, is all very untested and theoretical, and thus still has some outstanding questions. But is also the subject of his patent application, which of course isn't proof of much of anything useful to a non-mech.

[user removed]

Having some trouble sleeping tonight so I though I would use the time constructively.

The scenario is a long steep grade of lets say 8% for several miles. The elevation change would be 2800 feet vertical.

In my VX you just have to bite the bullet and downshift and run the engine at 4k RPM or somewhat near that to keep your speed at 60 MPH. This is the type of situation where you will see the big rigs struggling to maintain 35 MPH in the truck lane on the right side of the road. There is a grade like this near Blacksburg Va, that I have driven many times on Interstate 81.

This is where you want your vehicle to be as light as possible. Even the battery in a Prius would probably be depleted by the time you reached the top of that several mile 8% grade.

How do you handle it with the proposed hh?

First, you have to have enough engine to sustain the desired speed up the grade. Your energy reserve is depleted quickly (as Robert noted). Coming down the other side of the mountain will require no fuel and you will recharge the accumulator.

Remember the size of the engine determines the average percentage of overall recharge cycles versus engine off cycles, which in the INNAS setup was 11% running and 89% off. In this scenario the duty cycle would be 100% instead of 11%.

Downsizing the engine reduces overall vehicle weight and requires less total energy to maintain your speed up the grade, to the point in downsizing where you can no longer maintain the desired speed.

Too much engine size and power means you are using more energy to climb the grade.

Downsizing the engine can only be done to the point where you can maintain a reasonable speed during the uphill climb. The lighter your car the better.

If your car weighed 2200 pounds (just because it's easy to figure) you need 4 horsepower per second to climb one foot per second, or 32 horsepower at the wheels to climb an 8%grade, above and beyond what you would need to maintain the same speed on level ground.

If you added another 1100 pounds of passengers and cargo that would go up by 50%.
That means assuming you need 15 hp on level ground, 32 hp for the grade, and another 16 for the load you need to sustain an output of 63 HP.

Now you want to do that without having to run the engine too far outside its sweet spot, so you need to size the engine to produce that much power at the highest point of BSFC, which means it would need to be about a 140 HP engine if it was configured as they are in cars today.

Running at less than 3000 RPM at best BSFC, the engine would have to be about 2-2.5 liters to maintain best BSFC while producing that amount of total horsepower. The engine has no throttle control or full load enrichment. It is not designed to go over 3000RPM so you compensate with greater displacement. You could reduce that displacement and use some form of supercharging for this situation which would allow the displacement to be considerably smaller. In either situation you would design the engine for best BSFC almost without exception. Never full load enrichment, never idling, operating in the range of 1500-3000 RPM exclusively.

Going downhill on the other side of the mountain would be the same technique as the hypermiler uses. The accumulator would be rapidly recharged and you would have to use engine braking to keep your speed down to the desired level.

Additional safety could be incorporated into the in wheel drives by allowing them to push fluid through a bypass circuit with a restrictor in the circuit for additional braking if it was needed.

And yes, as the law requires a separate mechanical emergency friction brake on the rear wheels would be there in case the several other systems failed simultaneously. This was discussed at Tech, and there are multiple redundancies in the system as described.

The tactic is the same as a hypermiler would use in a conventional vehicle in the same situation and mileage would suffer compared to flat land cruising much the same it would suffer in any other configuration. Even in a BEV like the Nissan Leaf the energy required to climb that much of a grade would have a significant impact on your range.

Adding any type of storage capacity to try to recover more energy, adds weight to the vehicle and requires more energy in the climb phase.

The best energy source in this example would be liquid fuel, with diesel being the best choice of the liquid fuels due to its energy density which far exceeds any battery or accumulator as has been noted.

Arguing the energy density point will always place the accumulator or battery at a serious disadvantage compared to a gallon of fuel, be it diesel, gas, bio diesel,or alcohol.


Second point:

As far as how you convert your fuel energy into accumulator reserve. Let me see if I can make it clear.

As the various energy conversion systems mature over the next decades, what is now the best method could easily change very quickly, if a breakthrough is made in one technology.

We have no control over that progression. We can only make predictions as to how it will evolve. 20 years from now it may be batteries have the energy density of a tank of fuel. No one really knows for sure.

Right now, if you look at the percentage of vehicles on the road in the US gasoline is the obvious winner, propelling close to 19 out of 20 cars on US highways. Europe has a much higher percentage of diesel cars.

Its not which fuel conversion system I think will be the predominant one now or at some point in the future. The powertrain system I am proposing would be just as effective with any one you want to choose.

Maybe the battery issue will be resolved and we go all electric.
Maybe the IC engine will see efficiency hit 60% on bio fuels.
Maybe my engine design might have a place, even if only for a few years or decades.
Maybe something completely new will appear and render all of the above irrelevant.

I love the idea of capturing energy from the sun, tides, and wind. They are all related to the suns heating and evaporation of water, and the moons gravitational effects on the Earth. I also like geothermal energy, since it is almost limitless. Hydroelectric is another preference as long as its environmental effects can be mitigated.

I do believe fossil fuels will someday become obsolete as our prime energy source, but for the time being my philosophy is to get the most work out of every BTU of energy you use regardless of the source of that energy, and the less environmental risk involved the better as long as it is done rationally with some consideration for cost effectiveness.

regards
Mech