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Spring Loaded Acceleration Booster

Time shifted torque
  [vote for,

Consider, if you will, a device that could store torque while it's being generated but not doing useful work, such as when a car is idling at a stoplight, and release it when it is useful, such as immediately upon takeoff from said stoplight. It would use essentially the same spring mechanism as a windup watch, but on a larger scale. Excess torque could also be stored while coasting downhill, to be reapplied on a subsequent uphill climb. As a side benefit, if there is leftover torque when the car stops, it can be used to help crank the engine in case the battery is a bit weak.
ytk, Apr 18 2011

Be the flywheel Be_20the_20Flywheel
Here is my spin on this concept. [bungston, Apr 18 2011]

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       It is called regenerative braking, and it isn't stored in "lossy" springs. It is stored in "lossy" batteries.   

       Alteratively it is called a flywheel, and is baked, possibly WKTE.
4whom, Apr 18 2011

       Of course you may be refering to the modular clock-spring unit contained within the "Home-Sweat-Home" project, which seemed to have been rent-downunda by a particularly sensitive antipodean.
4whom, Apr 18 2011

       Regenerative braking requires an electric motor, either as the sole method of propulsion or as part of a hybrid system. This is just a single component that only requires a slight modification to an existing powertrain design. Also, regenerative braking only generates energy while braking, whereas the primary purpose of this is to store energy generated while the engine is idling that would otherwise be going to waste. Many cars that employ regenerative braking are able to shut off the engine while the vehicle is stopped, nullifying this loss.   

       One could use a flywheel for this design, but those have their own problems, including frictional energy loss (making it hard to store energy for a long period of time), and overall would represent a more complicated design, with a lot more moving parts.   

       And with either method, you have the problem of scale. If your electric motor can only generate so much torque, the only way to increase that is to put in a bigger and more expensive motor. You could spin your flywheel faster, or make it heavier, but then you run into tricky materials engineering problems, not to mention the increase in gyroscopic forces that would have a negative effect on the handling of the car. With this system, all you need to do to increase the amount of power available is use a bigger or stiffer spring, and perhaps change the gear ratios on the input and output shafts.
ytk, Apr 18 2011

       //With this system, all you need to do to increase the amount of power available is use a bigger or stiffer spring// You forgot to mention a heavier, more expensive, and possibly made from Unobtainium, spring. I presume you have used an ideal spring in your mental maunderings.
4whom, Apr 18 2011

       //whereas the primary purpose of this is to store energy generated while the engine is idling // Not much about conservation of energy in there, is there? Winding up a spring whilst the engine is idling would mean it is not idling (operating under no load), one would assume.
4whom, Apr 18 2011

       //Winding up a spring whilst the engine is idling would mean it is not idling (operating under no load), one would assume.//   

       Idle doesn't mean it's operating under no load whatsoever. Idle is just the speed the engine runs at when the throttle is closed. In this state, the engine still has to power the alternator, oil pump, air conditioning, and so on. And regardless of what it needs to power, it needs to maintain enough speed to run smoothly, even when there's not much load on it. There's still enough leftover torque produced by the engine in this state to move the vehicle, albeit very slowly. In the case of a manual transmission, you decouple the engine from the transmission by use of the clutch, so that torque effectively goes to waste. With an automatic transmission, that extra power is simply used to slosh transmission fluid around inside the torque converter, since the output shaft of the torque converter is locked by the brakes. In either case, the engine needs to be producing enough torque at any given time to start moving the vehicle immediately, but until the vehicle is actually requested to start moving, that torque could be used to drive something else rather than simply being thrown away.   

       But regardless, the point of this isn't necessarily to use less energy overall. Rather, it's to produce more peak torque for a short time than would normally be available from the engine alone. To that end, a spring of any size made of any sort of material would provide at least SOME benefit, and to improve that benefit you would only have to find the optimum material/size/cost tradeoff for however much extra torque you want to be able to produce and for how long you want your reserve to last.
ytk, Apr 19 2011


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