I was just thinking about engines (as I often do), and how to get maximum power. Obviously directly chaining two engines together, like an F1 and a diesel, doesn't work. But the idea behind it is solid: use two engines, one for low-end torque off the line, and another for high-end horsepower. Additionally, there has always been a tradeoff in building engines between power and being "streetable". Your V8 monster may make 600HP, but idles at around 2500. That doesn't work very well on the street But what if it could?

The prius uses a planetary gear setup to allow both an electric motor and a piston motor to control the same transmission, either independently or at the same time. The electric motor is used in stop and go situations, while the piston motor is used for highway speeds. Of course the goal of the prius is fuel economy. Take out that wimpy 3-cylinder, and put in a monster V8 (or whatever your choice of engine is ). Your engine may not be able to idle at "streetable" speeds, but so what? You have the electric motor to cover that. Once you hit WOT, look out!

You could even take this a step further, and engines that were tried on their own but not practical now could be viable. For example, in the Chrysler turbine car trial in the 60s, people complained of it being sluggish off the line. The engine was fine if it was spooled up before leaving the line, but there's now a better way, using the above method. Then you'd have the high end power of a jet engine, without sacrificing the instant takeoff.

The prius has a 4 cyl engine not a 3cyl and it is not used for just the highway, depending on load, temp, battery life etc. Your idea in theory sounds good. If you can test drive a Toyota Highlander hybrid, it has 3 electric motors (one in the front and rear diff and one in the engine bay) and the gas engine, when you need the power (aka floor it) all 3 motors combined with the gas engine creates 276hp. It goes pretty good! Also somthing VW has been experimenting with is a supercharged and turbocharged engine, the supercharger for off the line power and then the turbo builds boost it continues the power band.

[This message has been edited by Gumby (edited 11-23-2006).]

intresting.... seems good in theory
but how do we fit all that in a fiero? lol

The Prius 0-60 mph time is at least 1 to 1.5 seconds faster than a stock Duke with manual transmission. I have one and it certainly surprises many who decide not to get behind you at a stop light. As it turns out they get behind the "slower" guy next to you. ZOOM. Ed

------------------

i think the vw super / turbo motor is actually already in production .i read about it being 1.3 litres and with the same power as a 3 litre motor.the main goal is fuel economy.when it isnt floored it uses very little fuel.and above a certain rpm ,the supercharger disengages and only the turbo provides boost.

quote Originally posted by kwagner: I was just thinking about engines (as I often do), and how to get maximum power. Obviously directly chaining two engines together, like an F1 and a diesel, doesn't work. But the idea behind it is solid: use two engines, one for low-end torque off the line, and another for high-end horsepower.

I've been thinking about this a lot lately. I agree with everything you said. Electric motors are great off the line. They can produce maximum torque at zero RPM, something no gas engine can do. So the electric motor can make many types of gasoline engines more streetable.

When gas hit three dollars a gallon I was thinking about building a hybrid for maximum efficiency. But you could build one for maximum performance just as easy. The hard part would be linking the two motors together, and then how to control them. You could just chain the motors together as you say, but efficiency would suck on that. I supose you could find a Prius in the wreckers and reverse engineer it for a Fiero.

As for the control, you would need a lot of software to figure out how to control both motors. You would want an AC motor to be able to use it to regenerate the battery pack. And speaking of batteries they are not cheap.

In total a hybrid is not going to be cheap. It would cost you well over $10K just for the electrical stuff, now add in all your custom hardware.

But you would definitely have something cool. And you would surprise a bunch of people with all that torque off the line.

While we're on the topics of slightly oddball designs, how many of you understand how the variable transmissions work?

With a normal transmission, you put it into a low gear, rev your engine from a point where it produces almost no power, past the point where it's getting it's best gas mileage, and up to making peak power. Then all of a sudden you Stop accelerating, let the engine drop back down to producing almost nothing, switch gear ratios to a bit higher, and start over again. During the process you're only at peak power or gas mileage for a total of a few seconds. Most of the time is spent getting to the best engine speed, instead of actually running at it.

A Continuously Variable Transmission is usually built with a metal belt of sorts between two pulleys. You start off at the same low gear ratio as a normal car and rev up to your peak power/mileage RPM. But then you just keep the engine there while the diameter of the pulleys changes to increase the gear ratio. No shifting, no constantly changing engine RPMs. Just smooth power delivery and acceleration, making the best possible use of the engine's power. Only real problem with these transmissions is that they're not yet strong enough for a really powerful engine.

Most of the Hybrids out there are running CVTs as they do tend to maximize efficiency.

NISSAN is the only company prepared to market CVTs on a broad range of "normal" cars, (non-hybrid).

As technology improves I'm sure it could be adapted to a wide range of power handling capability. Now all we need is one in Fiero bolt pattern.

Audi'll sell you one in their A4 and such as well.

If you want to see how a CVT tranny works in theory, go look under the hood of a older snowmobile. 2 pullys and 1 belt. one pully is wide open giving a small radius the other is closed giving a big radius at zero engine rpm's it fives a incredibly low gearing ratio and tons of power. as the speed increases forces close one while opening the other creating a high gear ratio at top speed. you go throught all gears smoothly keeping it in the power band as you accelerate.

the ones in the hybrids simply have steels belts and other more durable parts.
It's actually really simple and has been around for hundreds of years.

My moped uses one, so I know first hand how nice they are. The simple small ones work on weights, which as the speeds increase, push outward on the movable part of the pulley to slide it in or out.

the saturn vue had a cvt called vti in 2002 and it bombed, guessin that no "good" cvt is gonna bolt up.

------------------

1985 GT Fastback
Low Original Miles at 41,506!!!
01 Cavalier Z24 16" wheels
KYB shocks
KYB struts with coilovers-coming soon

If only money was no issue Although this setup would be geared towards those who are already pushing the limits of their engines, which means they already have some $$$ into the setup. Initial development would be expensive, hopefully costs could go down over time.

So there isn't confusion: the prius CVT is different from the standard belt-pulley style. See 2/3rds down this page: http://auto.howstuffworks.com/hybrid-car2.htm That's what makes it ideal for this idea. The fact that it's not designed for a fiero is a mere technicality Unfortunately, the Prius is the only hybrid I know of that uses a planetary system, which means either adapting it or getting a custom one made

quote Originally posted by kwagner: So there isn't confusion: the prius CVT is different from the standard belt-pulley style. See 2/3rds down this page: http://auto.howstuffworks.com/hybrid-car2.htm

You and I must think alike. I was just on that page at "how stuff works" I think it would take a lot more than just adapting the transmission. There is one for sale on ebay right now if someonoe want to try though.

http://cgi.ebay.com/ebaymotors/2005-Toyota-Prius-Hybrid-Auto-Transmission_W0QQitemZ230056299399QQihZ013QQcategoryZ33727QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Here is the perfect video of how a cvt works http://videos.streetfire.net/search/cvt/0/b99f4c8a-5110-45f9-afd2-984800d611a6.htm

sorry couldn't find how to link it.

quote Originally posted by bluhevn86: o.k. got link to work.

Thanks for the link, but as mentioned earlier the Prius transmission doesn't work anything at all like that. From the picture on ebay I can't even tell what side mates to the engine. It is a totally different beast from anything that has ever been built.

Honestly I would not call the one in the prius a CVT. It is ingenious though using the properties of a planetary and coupling the enectric motor directly to the drive system to vary the speed of the outer ring gear to adjust gearing speeds like that. It's a feat of engineering that is absolutely fantastic.

Calling that one a CVT is like calling a Model A Ford a 1/4 mile car.

That said, unless you are an automotive and electronics engineer I do not see it going into a Fiero easily. An aluminum adapter plate will have to be made as well as lots of other items and do notforget a custom computer to run it.

it would be easier to transplant the entire setup plus ECU from one into the fiero. and then you might as well get the other parts.... Problem is you will still be not as efficient as the origional donor car as the Fiero has bad aerodynamics and weighs a lot more.

I am thinking the ecotec swaps having the most potential for high efficiency versus ease of swap. if someone can get a double overdrive transmission or have a regular overdrive tranny rebuilt to have taller gearing would go very far in increasing efficiency..

Actually on that point... A 4T60 tranny rebuilt to have taller gears coupled to a torque motor like a 3.4 would do well. get 2nd and 3rd slightly taller gearing and set the 4th to turn 1950rpm at 70mph and you would have the best fuel economy possible out of the fiero with really easy to do swap parts.

Then seeing some N* swaps that get 25-30mpg new tech always trumps old tech.

quote Originally posted by jscott1: You and I must think alike.

You know who could really benefit from using this (and has the money and perfect platform to try it out on)?
http://blogs.cars.com/kickingtires/2006/11/leno_ecojet.html

http://greenplanet3.org/ev/
http://courses.washington.edu/me495ev/

just a thought

------------------
"Outside a dog, a book is a mans best friend... Inside a dog, it's too dark to read." - W. Churchill

didnt the model t ford have some sort of planetary gear transmision ? this is nothing new , ,just clever adaptations of existing technology.which is all good.

Now here is an interesting thread!
Planetary drive systems can be found in many things. remember the old 3 speed bicycles with the push pun and hub on the rear wheel? it was a 3 speed planetary drive.
Many drill presses have cvt drives to set proper rpm for drilling, they use a wedge system to change the pulley sizes.
The prius is definately not a cvt system in a true sense, I think they called it that due to the set points for the usage of the various motors.
That ebay ad is only the tranny tho, I don;t think it includes the electric motor, unless it is built into the tranny??? a 67hp motor is not exactly that small, so I would think not....
But as far as using it, anything can be mated to anything, it only requires an adapter plate, and with an auto system, getting the flywheel (if they even use one) would likely require another adapter.
things like this motivate me to fix my milling machine.....
I had thought that a fiero might make a decent electric car, the newer motors and drive systems make it pheasable, but a hybrid system is definately the way to go.
unfortunately, cost is a very limiting factor, even if you were able to find a wreck, I'm sure ti would cost a bit to pull the system out, and the batteries would be the likely highest dollar item.

Personally I was mor thinking of adapting one of those yanmar 230hp 4 cylinder turbo IC diesels, they are high rpm, good to 4k rpm, and with a 5 speed, likely give you good performance and economy. they use them to replace 350 to 454's in marine applications, so I think it would work. just don;t have 17k$ for one in my back pocket....

What this forum needs is a good motorhead philanthropist

Back to the thread:
I don't think the prius has a flywheel or torque converter, and instead is bolted directly to the parts of the planetary gear. If one part of the gear system doesn't move, the rest moves around it, so I don't see a need for one.

Here's some specs of the prius, to know "what works":
http://www.toyota.com/prius/specs.html
http://www.electrifyingtimes.com/priustechspecs.html <- look at all those computers at the bottom!
And a Prius User Guide:
http://john1701a.com/prius/documents/Prius_User-Guide.doc

quote Originally posted by jscott1: Most of the Hybrids out there are running CVTs as they do tend to maximize efficiency.

From all the MPG numbers Ive seen, CVT's are less efficent (up to 7 MPG) than conventional trannys

I see a lot of people talking about how the Prius CVT works (yes, it's a CVT... just a different type than what's in a snowmobile) but not too many that seem to have researched it. I did lots of research before buying my Insight in 2000 and here's a few pointers about how they work.

Honda offers a CVT in their hybrid cars. This transmission is very similar to the variable-pulley snowmobile drive discussed earlier. It uses hydraulic pressure to vary the pulley diameters as well as to maintain proper tension on the belt. The belt is a rubber/steel affair that consists of triangular steel blades set on a rubber/fiber belt for flexibility. The system has a computer-controlled, hydraulically actuated clutch on the output shaft so that the expanding pulleys are constantly turning and can be adjusted by the computer while the car is stopped. This trans is available in both the Insight and the Civic while the Accord makes use of a standard electronically shifted automatic. The Accord is considered to be a performance hybrid rather than a green car due to it's using a standard V6 and getting extra torque from the electric drive. Both Insight and Civic are also available with a 5-spd which gets better mileage than their CVT counterpart.

On the other hand, Toyota's "Hybrid Synergy Drive" is not available with a manual trans. The system is in fact completely dependent on that planetary drive everyone keeps talking about. While it is fundamentally similar to the planetary systems involved in a 'normal' automatic it is utilized in a completely different manner. You will not get this system to work without a computer nor will you be able to install it onto a 5-spd or TH125 transmission. Swapping the Toyota drive into a Fiero would be a whole-hog swap as the hybrid system is a true system dependent every part of the drive for it's functionality. Here's a rundown of why...

Firstly, for those who are unfamiliar with how a planetary gear set works I present this page: http://science.howstuffworks.com/gear7.htm

The Toyota drive has exactly one planetary gear set in it. Connected to this are the ICE (Internal Combustion Engine,) GM1, and GM2. The GMs are Synchronous AC motors that can act as motors or generators. Connected to the outer, or Ring, gear of the trans is GM1. Also connected to this gear are the differential and drive axles. So, by rotating GM1 the wheels can be directly powered electrically.

Now those who know a thing or two about planetary gears will say that this means at least one other part of the gear set must also be turning and this is true. Attached to the innermost portion, or Sun gear, of the gear set is GM2. GM2 is smaller and less powerful than GM1 but by running this unit backwards you can keep the central portion, or planet carrier, of the planetary system stationary while the wheels turn. Guess what's attached to the planetary carrier ring? The ICE!

So now that you're moving and continuing to accelerate you want to bring the ICE into the picture and make use of it's high-RPM power to continue propelling the car. Simply bring GM2 to a halt using electrical braking and the ICE it forced to turn over. Once it is running the speed of GM2 can be continuously varied to modulate the RPM of the ICE with respect to the wheels while forcing it to provide power for either the wheels or the batteries, all dependent on how much power you are generating with GM2.

See, so Simple! No, not really. Thus the need for a computer to control the works. I have contemplated since early on the possibility of a Hybrid Synergy driven Fiero. However, getting the batteries into the car would likely be a headache as would getting all the gauges playing nicely. I suspect it would be a matter of stripping the car's electronics and starting with a nearly bare frame and a nearly whole donor Prius. : / Installing a Civic drive would be much easier as the ICE and electric motor are basically one unit...

So.... any questions?

Red 5spd Formula (still MPFI-powered...)
Trot, the nerdy, fox...

quote Originally posted by 86GT3.4DOHC: From all the MPG numbers Ive seen, CVT's are less efficent (up to 7 MPG) than conventional trannys

I should have been more specific...As a system the CVT is more efficient than a manual.

Honda stopped offering the manual transmission in the Insight because pushing in the clutch disconnects the motor and you lose efficiency, but more importantly you get no regenerative braking effect when you are slowing down if you push in the clutch while slowing down.


Installing the batteries would be the least of the difficulties in the Fiero Hybrid. To get the Toyota system to work you would have to install every piece of the synergy system and then still probably re-program the computer to optimize it for the Fiero. Maybe someone eventually will figure all that out, but it doesn't sound easy.

In theory, a CVT should be more efficiant than a manual. In practice, that's not always the case.
One of the reasons I suspect is how it shifts. Most of the CVT makers have decided that a driver will freak out if their car doesn't have a sudden lurch and change in engine noise to indicate a shift. So rather than smoothly changing the ratio, it essentially turns itsself into a 5 speed automatic. Were this not the case, I think they would do a bit better in the mileage department.

quote Originally posted by TrotFox: So now that you're moving and continuing to accelerate you want to bring the ICE into the picture and make use of it's high-RPM power to continue propelling the car. Simply bring GM2 to a halt using electrical braking and the ICE it forced to turn over. Once it is running the speed of GM2 can be continuously varied to modulate the RPM of the ICE with respect to the wheels while forcing it to provide power for either the wheels or the batteries, all dependent on how much power you are generating with GM2. See, so Simple! No, not really. Thus the need for a computer to control the works.

Thanks for adding some more detail to the discussion

I'm still not convinced you need a computer to control it. Why couldn't you just put two levers in place of where the auto or stick shifter used to be, one for GM1 and one for GM2? Yes, it would be clumsy at first, and yes there's better options out there as far as ease of use. But nothing is required beyond controlling the speed of those two, correct? When the ICE isn't on, those are your throttle, essentially. And add some gauges to see what is doing what (voltage on each motor, amps going to/from batteries). After a while, it will become as easy as driving a car

quote Originally posted by Jax184: Most of the CVT makers have decided that a driver will freak out if their car doesn't have a sudden lurch and change in engine noise to indicate a shift.

The new Nissan makes a point of the fact that there is no "Shift Shock" and smoothly accelerates through a continuous range.

Kwanger - I'm sure it's possible to do it manually. About 100 years ago it was considered impossible for a human to control an airplane because it would require too many adjustments that were thought to only be hardwired into a bird's brain.

quote Originally posted by kwagner: Thanks for adding some more detail to the discussion I'm still not convinced you need a computer to control it. Why couldn't you just put two levers in place of where the auto or stick shifter used to be, one for GM1 and one for GM2? Yes, it would be clumsy at first, and yes there's better options out there as far as ease of use. But nothing is required beyond controlling the speed of those two, correct? When the ICE isn't on, those are your throttle, essentially. And add some gauges to see what is doing what (voltage on each motor, amps going to/from batteries). After a while, it will become as easy as driving a car

Sure, you could do that but you still need a microprocessor driven inverter for each GM unit. They're synchronous AC motors, not DC dynamos and require a good deal of electronics to control. I suppose you could find out what their volt/RPM ratings equivocate to and run DC motors in their places but then you're looking at controlling de/acceleration directly with a pair of hand-levers. Accidentally bump one and you're sending the car hurtling down the road, or the ICE's RPMs through the roof.

Yes. It's possible. That doesn't make it a good idea. } ; ]

Red 5spd Formula (one go lever!)
Trot, the potential, fox...

And lets not forget, what happens when the tranny explodes when you put more than 42.1 ft lbs of tq through it. I dont know what the actual power ratings are, but I can scarcely imagine how well a the steel toothed fiber belt described above would hold up to a 300 ft lb LT1. The electric motors do make max torque from 0 RPM, but they dont make all that much of it, if you're talking about using a CVT for performance gains, whats the point if you cant put a decent motor behind it.

quote Originally posted by TrotFox: Yes. It's possible. That doesn't make it a good idea. } ; ] Red 5spd Formula (one go lever!) Trot, the potential, fox...

How often do you accidentally bump your shifter? I'm not saying it's a perfect solution, I'm saying it's possible. And I actually don't think it would be as bad as the worst-case scenario you offer. Someone could shift from 4th to 3rd instead of 5th, yet there are still 5 speed stick shift transmissions available. And the transmissions we have today have evolved from less optimal designs of the past. This is still fairly new ground being covered, it will take time to make an elegant solution. That doesn't mean things shouldn't be tried in the meantime.

quote I can scarcely imagine how well a the steel toothed fiber belt described above would hold up to a 300 ft lb LT1.

This isn't using a steel belt CVT, this uses a planetary gear setup. They can be found in automatic transmissions (among other things), some of which are behind very powerful engines. So it's possible to build one to hold the power.

quote Originally posted by kwagner: This isn't using a steel belt CVT, this uses a planetary gear setup. They can be found in automatic transmissions (among other things), some of which are behind very powerful engines. So it's possible to build one to hold the power.

I agree with you that this planetary system will be fine with higher power systems, but it'd need to be custom built as the system in the Prius is only designed for that little 4-cyl. It certainly should be scalable though... The new Camry hybrid is a performance system in the same way Honda's Accord hybrid is and so far as I know it still uses the Synergy Drive system... nope, it's only a 4-cyl in the Camery but it has a 200ft/lb electric drive. The ICE is about twice as powerful as the Prius offering though. Their site shows RPM specs for the motor and ICE and such so it could be used to reverse engineer the system.

My primary fear with bumping the lever on the system you propose is that we're not talking about a shifter, we're talking about a potentiometer with a stick on it. You'd want to make it rather difficult to move... maybe using detents. You'd certainly want them out of reach of the passenger for safety. A manual transmission can only be shifted easily when there's no pressure on the system. A potentiometer can move anytime. This idea might be fun to flesh out in a smaller format for purposes of testing... Say in a go-cart with a 5 horse Briggs? Might be neet to have the worlds first hybrid go-cart. } ; ]

Red 5spd Formula
Trot, the pondering, fox...

quote Originally posted by 86GT3.4DOHC: . The electric motors do make max torque from 0 RPM, but they dont make all that much of it, if you're talking about using a CVT for performance gains, whats the point if you cant put a decent motor behind it.

I don't know where you got your info, but the Prius electric motor makes almost as much torque as an LT1...and at ZERO RPM!


Electric Motor:
50 kW power
67 hp @ 1200 - 1540 rpm
295 lb-ft torque @ 0 - 1200 rpm
500 volt AC operation

I think you missed something. they are not synchronous ac motors. an synchronous motor has a set rpm, and does not vary from that. these are variable rpm motors. A minor point. The control for them is not out of the question, go to any of the electric car sites and they have controllers for ac motors. they are analog devices, as they work off the throttle controller. now in the prius trany, you have to use them for electric braking also to allow the ICE to input, also fairly easy to implement with set points relative to speed and throttle and brake inputs. while levers are the frankenstein approach (sorry, no offense) a simple state machine would be better suited to this task. a fully developed computer control would get the best efficiency, but to make the car drivable, even an analog circuit could be built to handle the task.

quote Originally posted by tjm4fun: a simple state machine would be better suited to this task. a fully developed computer control would get the best efficiency, but to make the car drivable, even an analog circuit could be built to handle the task.

Sounds like an opportunity for someone who understands this stuff to help out the homebrewed hydrid community.

I have searched all over the web and there is almost no information on building parallel hybrids. The conventional wisdom is to build a series hybrid, a regular electric car with a gas powered generator. Where is the fun in that??

If I were retired and had some money, I would love to try something like this. but alas, with 2 in college, I have no money, and working eats up my time.
Would be fun to get back to using the EE for real design work....