Spin on Hybrid Cars

Interesting tech....@60mpg

What I haven't been able to figure out from ANY of the hybrid designs is why they insist on using engines NOT optimized for a single speed, and running at that optimum speed. For any intake tract, any exhaust tract, and any combustion chamber design, there will be one engine speed or speed band (fairly narrow for maximum naturally aspirated efficiency) where the HP and Torque will be at least overlapping, if not superimposed.

This holds true for any internal combustion engine design, regardless of cycle type, and whether it is a piston or a rotary, or even a radial engine, as far as I can tell.

So, in the dual interests of longevity and efficiency, why are they NOT designing the engines for hybrids so that they run slowly, while also running at peak efficiency, torque, and horsepower? Surely enough is known about IC engine design by now to be able to reach a strong compromise on all of those, and do away, for hybrids, with the lack of (relative) efficiency demanded by the use of engines designed to run at a wide range of RPM.

Or am I missing something important? Please, I know a lot of you guys know more than I will ever know about engine tech. Please enlighten me. I would benefit from your knowledge.

Thank you

Well I think they do that in the Volt....

Thanks. Reading the documentation, I don't see any indication that it is a fixed speed IC motor. In fact, the fact that it can be linked to the electric motor to boost its output, via the electric clutch, almost guarantees that it has to run across a range of engine speeds. I looked for the typical "power at RPM" blurb, and didn't see it, but that doesn't mean it runs at a fixed speed. It only means that is its peak power output.

I guess if I were to look at the spec for a fixed speed engine, I'd need to see one where the ONLY thing the engine did was power a gen-set, to charge the batteries, with any excess being available strictly as stored or generated voltage dumped across the electric motor(s). That isnt' what the "electrical clutch" indicates to me, since you wouldn't need a clutch at all to do it that way.

Well I think efficiency is always going to be at the mercy of demand for a private vehicle...I think the range boosters they sell are fixed though....

http://evworld.com/news.cfm?newsid=30986

But I like the idea of not having to charge a battery pack to get good performance with good MPG...I would like to see this tech with a 2 liter engine, if they could double the performance giving 500ftlb torque@30mpg they would be perhaps cheaper than a comparable straight V-8 at $10g+....

Yeah, demand for "The way it used to be", which is almost always based on the convenience I paid good money to buy, will almost always trump the long-term money savings that an owner could see with an optimized engine, designed for longevity and efficiency.

One of the reasons marine diesels last so long is because they tend to run for hours at a time at one steady speed, regardless of what that speed might be. It seems to me that if we REALLY want to solve one of the pieces of hybrids lasting a long time (battery tech still being a weak spot, but getting better all the time) we would be looking at a long-lived engine design, whether diesel or something else, making use of the highest efficiency possible.

And I drove a Prius around for two weeks out in California in the fairly early days (it was a rental, and I WAS GLAD I didn't have to worry about replacing batteries) and I absolutely loved it, and found that it had plenty of grunt when I needed it.

Electric motors, providing all their torque at zero RPM, and all their HP at the other end of the spectrum, can really make a small power system deliver a punch. But I did notice that when the engine kicked in due to excess instant power demand, it responded to the throttle like all gas engines.

And the Honda Incite Hybrid which was also much to be seen at the time, used the gasoline engine, augmented by the battery power on excess demand, which seemed to me to be ignoring the longevity of electric motors in favor of putting a lot more wear on the gasoline engine.

So Toyota went the way I thought was wiser, but neither one of them used a fixed engine speed driving the genset, the way a portable or fixed-plant generator does. And I still think that would yield best long term efficiency and longevity.

The early Volts that were built as prototypes did it that way, but then the final one that hit production did not. It made the mileage drop drastically in the final production model, done that way because the public didn't like the constant speed motor??? I have a friend in the Southern California area that was lucky enough to get a prototype unit because he was in the EAA. His commute to work gets hime nearly 100 mpg while a neighbor with the same number of people in a production Volt going from the same area to work in the same facility gets just a little over 40 mpg. They have swapped out cars to make sure it is the car and not the drivers. GM gave the public what the public wanted. Vroom-vroom. Same with an electric car which makes more noise than a normal car because some congressman wants it that way and insists that a speaker be in the front of car with an audible signal.

actually your general thinking has been approached before. the idea was get a great running engine and have a variable transmission adjust to load. personally this use of turbo, blower and super caps seems quite logical to me

I don't see the strain of minimal boost being much of a factor here, especially with the new advanced lubricants available now....

http://www.sdsefi.com/techmods.htm

The term is "Power Averaging" and the challenge is "Variable Demand."

Constant output not only increases potential operating efficiency it also has the advantage of reduced volume and mass fraction dedicated to the prime mover.

It would be very difficult to get the prime mover to operate at invariable power output but not so difficult to get the prime mover to operate at much reduced variability.

The down side, if there is one, is that storage is required for peak power requirements such as acceleration and grading. But since regenerative braking has such a high payback in ICE prime mover vehicles; that storage is required anyway.

The up side to power averaged hybrid vehicles is that the storage device only needs to capacitate an energy equivalent equal to the translational and rotational kinetic energy at maximum operating speed. For super high performance that storage device can be scaled to lets say 4 times that value.

Here is a link to something I wrote some number of years ago.

http://www.bestsyndication.com/Articles/2006/c/carter_mark/031206_hybrid_cars.htm

or

http://cr4.globalspec.com/thread/37460

My first study of power averaged - regenerative capable transportation technology was paper modeled as a switching locomotive; using off the shelf technologies available at the time - 1978.

The fueling algorithm is an interesting challenge but appears it could be quite elegant in simplicity.

The greatest challenge is the storage device since the power density in acceptance must be quite high. This could probably be overcome by combining super capacitance with chemical storage. The Maxwell Boostcap technology is a game changer for this application.

You might want to look at the information about trains (not switching locomotive) but Hybrid trains that GE is proposing. If you can get into the actual technical data, it is very interesting. My son sent me great info on this before his retirement (at age 39) and The GE system uses liquid Na (sodium) which our local utility also uses for it's Solar installation. (Google "Los Alamos solar project.) They are quite good, but would not work in a car.

I have my own hybrid project (not a train) with totally different batteries. My design uses "a metal", carbon, and air. Plus some extra additives. Theoretically the power to weight and volume is in the neighborhood of 20X the best batteries available now for cars. Time will tell whether the theory is correct or not. Enough said.

Thanks, Gavilan, 4wsilver,these are the kinds of answers/analyses I was looking for. So it seems like a good idea, and from your comments, it looks not only "doable", but sellable in the current economy.

Maybe we'll see this change happening soon. One who does not want to be chained to the current cost of fuel, but is not willing to buy tech that would force me to take a break every 7-8 hours to recharge for 10-12, might be willing to accept the changed performance specs accompanying the long-life and economy such a design might afford.

Not exactly related, but I did see a Tesla parked at a hotel near our HQ this morning! Check out a few pictures on our Facebook page:

https://www.facebook.com/CR4News

I think if you want a hybrid and eat your cake too, here is what you should consider: (check all three pages)

THE BEST HYBRID

If we funded with taxpayer money the conversion of ALL vehicles possible to this technology, the payback would be an instant boost to our economy on par with conservation funding. Instead of cash for clunkers, it would be cash for boosters!