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Why is it that the engine is carried by the frame? Isn't it possible to create an engine that is an integral component of the frame? The pistons could be linearly mounted on a crossmember with vibration boots at each end to absorb the vibration of the engine. In a sense it would still be carried,
but it would serve a dual purpose by providing cross member support and being an engine. This should drastically reduce the weight of a car.
Pennington Autocar
http://www.beaulieu...otordisplay.cfm?C=T
Cylinders double as frame rails [Ned_Ludd, Aug 29 2007]
[link]
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Are you talking about using the engine
block as a structural compenent? If so then
that's already done, at least in high end
race cars. |
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Thanks, cool to know that. What's wrong with Detroit? Get it to the people! |
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Some earlier motorcycle designs use the engine as a structural member as well. |
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formula 1 cars and motorcycles do this everyday |
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If you carry on this way of thinking, next thing you know you'll have invented the aluminum monocoque. |
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The Lotus 25 designed by Collin Chapman was the first to use both effectively. |
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Somewhat peeving if you crack your engine block, no? |
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this has been done since the 1920s on tractors
gd idea tho
thanks
Nick |
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The reason that the engine is only a 'stressed member' in supercars is that the vibration is not dampened like it is in most production cars, it's transmitted through the rest of the chassis. |
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Making the engine a stressed member in a car isn't like in a motorcycle. In a motorcycle, due to how the vehicle itself changes attitude during manuevering, the stresses remain fairly constant through the frame. There is some small twisting or bending due to drive stresses, but not like what the frame would experience during handling if the motorcycle remained upright. Making the block sturdy in one direction is no problem. |
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A car, however, is stressed from side to side during handling, and also is subject to strong twisting stresses because of its four contact points and the natural variations of the road's surface. While the engine block is very strong, it will change shape, however minutely, as it is subjected to theses stresses if it is employed as a stressed member. The changes of internal clearances will be small, but the clearances are small enough already. A little too much twist or bending could easily force clearances to close up, bring sealing surfaces out-of-round, etc. All this plus the vibration isolation argument would move me to recommend against ever using the engine block as a stressed element in the structure of a car. It's one thing in a high-buck race car that only has to hold up for a few hundred miles and will run on a closed, smooth track, but for the family truckster running the streets of Chicago, no way. |
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The bit about tractors is true, with a caveat: weight is not a bad thing on tractors, so it is easy to add enough material to make an engine block so ridiculously strong that it can serve as a stressed element and still not suffer undue changes in critical measurements. |
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I should add that many tractor manufacturers are moving away from the unitary construction of old and are now designing tractors that carry their engines and drivetrains in frames, and even sport front suspensions to smooth the ride and reduce stresses on both operators and machinery. |
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i cannot wait until the tractors coming through these days turn into classics and become affordable to the classic tractor collector
but as testiment to strength of the stressed engine is that i can drive full throttle accross a field with bomb holes a foot deep and the tractors survives!
thanks
Nick |
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