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10-28-2008, 09:07 PM
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#11
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Registered Member
Join Date: Apr 2008
Posts: 1,264
Country: United States
Location: up nawth
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The key component is the variable displacement feature of the in wheel drive motor-pumps. They can be changed from 0 stroke to any stroke position within their design range. They can also be reversed to regenerate and provide a reverse "gear". This displacement change can occur as fast as you can apply your brakes in your car.
The diameter of the cylinders and their maximum stroke are sized to allow the pump function to capture the regenerative energy up to the limit of the tires traction with the road. Regeneration would continue until the wheels stopped completely, then the stroke position would go neutral until you accelerated again. This is at all 4 wheels, both acceleration and regeneration. With the best available tires this car could out accelerate any 2 wheel drive car on the planet!
Think of it like being able to downshift you car into first gear at 100 MPH and spin a flywheel with that energy or store it in a 5000 PSI accumulator.
This means you have the ability to stop at your maximum rate, and also accelerate at the same rate.
Imagine your car could accelerate at the same rate of acceleration as its best braking distance. You are talking 0-60 in about 130 feet!
Thats possible with the engine turned off! However it is only available once.
The amount of energy wasted in a 60-0 stop is the same as the energy required to maintain 60 MPH for .7 mile.
The ability to run the engine only in its best BSFC range means you can double the mileage with that single fact in mind. Energy provided by the engine can be applied to directly driving the vehicle as well as storage simultaneously. Eliminating idling saves 13% of total fuel consumption. You dont need a conventional starter motor, the hydraulic accumulator starts the engine. You only need to generate electrical power to run your accessories. You dont need a large battery to start your engine. The battery could be 1/4 the size.
Regardless of the storage level percentage you can always apply the power necessary to the wheels to maintain any speed, because you can constantly fadjust the stroke of the wheel motors to extract the same amount of power regardless of the level of available energy stroage.
Think of it as a bank in which you store 100s of horsepower seconds of energy. Your maximum is 1000, minimum is 300. If your energy requirement is 10 HP you could maintain that level for 70 seconds without any fuel consumed during that period. Then the engine replenishes the 700 Horsepower seconds by producing 100 HP for 7 seconds.
The size and maximum power of your engine can be varied greatly, with the only result being the time required to restore the 700 HP seconds of energy would be less with a more powerful engine. You need 100 HP from the engine at a RPM range from 1200 to 2500 RPM, but you do not need to design the engine to run at any higher speed than 2500 RPM. A single port and injector supplies all the air and fuel to the engine, while a single exhaust port allows you to keep catalist temps high as well as transfer exhaust heat to preheat the induction charge.
The engine would be fairly large displacement, probably 200 cubic inches, but would never run above 2500 RPM regardless of the circumstances.
No idling, no part throttle constant speeds, and no necessity for the components you normally have on your car to control the engine power production.
This same vehicle would be capable of accelerating to say 80 MPH, then stop, reaccelerate to 70 MPH, stop, reaccelerate to 63 MPH, stop, reaccelerate to 55 MPH, stop, and on and on>>>>>>>>>>>>>>>>>>>>
WITHOUT THE ENGINE RUNNING AT ALL> as long as your storgae was at maximum when you began the series of stops and starts.
I am hoping to achieve 85% regeneration efficiency, but 80% would be fine. 90 % would be even better but you have to have two transformations of energy and storage so the overall efficiency is the multiple of three separate component efficiencies. Each component would have to have efficiencies of over 96% individually. Very tough to do but not impossible.
If I wanted to spend the many minutes it would take I could pump an accumulator up with my legs and accelerate your car to 80 MPH with this system. Could be used to limp to the gasstation if you ran out of fuel. It would be a whole lot more efficient than pushing your car.
You could also start the engine with a totally dead battery.
regards
gary
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10-29-2008, 05:10 AM
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#12
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Registered Member
Join Date: Apr 2008
Posts: 1,831
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in a way, it works like an air compressor.
I am just trying to make sure I understand it. the accumulator is set at a given pressure and if it falls below that pressure the motor (car engine) kicks in to get back up to that pressure but the goal of the motor is to keep that said pressure. the wheels are actually ran off of the pressure that has been accumulated.
I know that I have "dumbed it up" but after reading your posts, my head was kind of hurting a little so I tried to relate it to something much simpler just to make sure I understand it.
obviously there is a lot more going on there than just what I have said. I like how you use the value hp/sec. that is pretty cool. I wonder, with your design, can you release all of it at one time? or at least at very high quantities? if you have 1000 horsepower seconds to play with, can you release 400 hp for 3 seconds or even 1000 hp for 1 second or maybe even 2000 hp for 1/2 a second. I realize that traction would be a big issue with that type of power at the rear wheels, I was just curious.
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10-29-2008, 06:01 AM
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#13
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Registered Member
Join Date: Apr 2008
Posts: 6,624
Country: United States
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Quote:
Originally Posted by jeep45238
Cow, the idea is to keep his original drive wheels and use the rears as a proof of concept.
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I understand the concepts and ideas; my point was that he's talking about asking the rear tires for a lot of braking traction that I'm not sure they'll have. If that's true, then it would make sense to use an originally-RWD vehicle and put the proof-of-concept system in front wheels.
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10-29-2008, 06:09 AM
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#14
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Site Team / Moderator
Join Date: Sep 2008
Location: Northern Virginia
Posts: 4,739
Country: United States
Location: Northern Virginia
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I agree. Its something like 70% of the braking is done by the front wheels. The rears don't do much. I like the idea of using a 4wd vehicle and disconnecting the front axle. You can buy an old 4wd pickup, or an old AWD Astro relatively cheap and have a cheap, simple vehicle to prove the concept, then once that is done you can work on refining it and engineering it into a newer vehicle. Personally I like the idea of using an old AWD Chevy Astro (or maybe an AWD Subaru Outback wagon?). Lots of room in the back for the extra equipment while experimenting. Once its tuned and refined the equipment can be located underneath the vehicle.
-Jay
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10-29-2008, 11:00 AM
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#15
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Registered Member
Join Date: Sep 2008
Posts: 139
Country: United States
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Quote:
Originally Posted by theholycow
I understand the concepts and ideas; my point was that he's talking about asking the rear tires for a lot of braking traction that I'm not sure they'll have. If that's true, then it would make sense to use an originally-RWD vehicle and put the proof-of-concept system in front wheels.
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It has more to do with weight transfer in braking than which wheels are driven. As long as the wheel doesn't skid, then it won't matter where the wheel is located. Rotation is rotation.
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10-29-2008, 11:14 AM
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#16
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Registered Member
Join Date: Apr 2008
Posts: 6,624
Country: United States
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Quote:
Originally Posted by jeep45238
It has more to do with weight transfer in braking than which wheels are driven. As long as the wheel doesn't skid, then it won't matter where the wheel is located. Rotation is rotation.
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Yes, that's entirely my point. When braking, the weight transfers forward. If one is to use the new system to gather energy from wheels by using it to brake those wheels, it's going to be tough to get much energy from the rear wheels, which don't have a lot of braking traction due to weight transfer.
Therefore, I suggest attaching the proof of concept system to the front wheels.
Perhaps there's something fundamental I'm missing here, possibly I failed to pay attention while reading an earlier post.
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10-29-2008, 11:30 AM
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#17
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Site Team / Moderator
Join Date: Sep 2008
Location: Northern Virginia
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Location: Northern Virginia
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Not only does weight transfer forward, but in most vehicles the weight of the engine is directly on top of the front wheels helping them keep traction. The rears will skid easily because there's no weight there holding those wheels on the ground. This could be dangerous driving in rain/snow/ice/wet leaves. it would be the equivalent of pulling the handbrake while trying to stop or slow down in low traction situations. There is more energy available from the front axle without breaking traction, or creating an unsafe condition.
-Jay
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10-29-2008, 03:53 PM
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#18
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Registered Member
Join Date: Sep 2008
Posts: 139
Country: United States
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Quote:
Originally Posted by theholycow
Yes, that's entirely my point. When braking, the weight transfers forward. If one is to use the new system to gather energy from wheels by using it to brake those wheels, it's going to be tough to get much energy from the rear wheels, which don't have a lot of braking traction due to weight transfer.
Therefore, I suggest attaching the proof of concept system to the front wheels.
Perhaps there's something fundamental I'm missing here, possibly I failed to pay attention while reading an earlier post.
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You are - the weight over the wheels, and how much of the braking they do proportionally does not matter. This is taking rotational motion and turning a pump. The wheel powering the motor could be on the front bumper, the rear wheels, dead middle, and it would still make the same amount of pressure and flow rate over the same period of time given the same deceleration rate assuming the wheel doesn't skid.
The energy doesn't move away from the rear wheels - they're attached to the chassis, which is moving, so all 4 wheels are spinning.
Remember this isn't anywhere close to threshold braking at all - 8% regeneration capacity judging by his charts, which won't be anywhere close to locking up the wheels.
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10-29-2008, 03:55 PM
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#19
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Registered Member
Join Date: Sep 2008
Posts: 139
Country: United States
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Quote:
Originally Posted by Jay2TheRescue
Not only does weight transfer forward, but in most vehicles the weight of the engine is directly on top of the front wheels helping them keep traction. The rears will skid easily because there's no weight there holding those wheels on the ground. This could be dangerous driving in rain/snow/ice/wet leaves. it would be the equivalent of pulling the handbrake while trying to stop or slow down in low traction situations. There is more energy available from the front axle without breaking traction, or creating an unsafe condition.
-Jay
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Hydraulics are not a 0% to 100% instantly unless you want them to be. They allow for a very precise fluid flow, and thus braking power. There's no reason to fear this setup more than a rear disk or rear drum setup in those conditions, assuming that both are properly designed.
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Democracy is two wolves and a sheep deciding what to have for dinner. Liberty is a well armed sheep contesting that decision.
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10-29-2008, 04:07 PM
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#20
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Registered Member
Join Date: Apr 2008
Posts: 6,624
Country: United States
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Quote:
Originally Posted by jeep45238
Remember this isn't anywhere close to threshold braking at all - 8% regeneration capacity judging by his charts, which won't be anywhere close to locking up the wheels.
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Ah, that is precisely what I was missing. I thought he was looking to regenerate a lot more energy.
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