# Pusher Trailer



## remy_martian (Feb 4, 2019)

Fun on black ice/snow for the adrenaline junkies

Why not just add steering and two front wheels? You can use the kitchen faucet as a tiller 😂


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## brian_ (Feb 7, 2017)

electro wrks said:


> Here's a new and interesting take on the pusher trailer concept:
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Somewhat related to the pusher trailer, but not actually pushing. In this setup the trailer could pull for regenerative braking; however, it would rationally (for stability among other reasons) never actually just push, but only reduce the pull needed from the tow vehicle.



electro wrks said:


> It appears some kind of connection senses the towing and braking forces at the tongue to power or regen brake the drive wheels. Something like the mechanical action of typical trailer surge brakes.


While a load cell in the coupler mounting could be used (like the hydraulic cylinder in a hydraulic surge brake system), and the drawing does suggest that's what the "strain relief module" might be, it could also use only acceleration to determine drive and braking forces (like typical electronic proportional trailer brake controllers).

From the article:


> The 22-foot travel trailer should be able to fit into a standard vehicle charging spot, allowing both it and the tow vehicle to fast-charge simultaneously on road trips.


I would be astounded if any Airstream owner in North America were to unhitch the trailer to charge - they'll just leave the trailer hanging out in the traffic lane, blocking traffic. In Europe, with different regulations, social conditions, and trailer hitch systems, I can see someone unhitching then using the trailer's power to slot it into a charging bay so they can occupy two of them and get both vehicles charged.


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## remy_martian (Feb 4, 2019)

Or in China...leaving the trailer parked in a charging stall.


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## electro wrks (Mar 5, 2012)

brian_ said:


> Somewhat related to the pusher trailer, but not actually pushing. In this setup the trailer could pull for regenerative braking; however, it would rationally (for stability among other reasons) never actually just push, but only reduce the pull needed from the tow vehicle.


From the article it looks like the trailer can push, when needed:

"The eStream has the potential to torque-vector and help stabilize not just the trailer but the tow vehicle together with it, aiding a smooth, stable tow in sway conditions or side winds. It also has the potential to actually help with traction—up muddy or snow-packed inclines, for instance." 

I would call it a pusher trailer because it is actually pushing itself down the road and at least occasionally, for very good rational reasons, pushing the tow vehicle as well.
Again brian, maybe you should read postings more closely before you comment.


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## brian_ (Feb 7, 2017)

electro wrks said:


> From the article it looks like the trailer can push, when needed:
> 
> "The eStream has the potential to torque-vector and help stabilize not just the trailer but the tow vehicle together with it, aiding a smooth, stable tow in sway conditions or side winds. It also has the potential to actually help with traction—up muddy or snow-packed inclines, for instance."


Stabilizing is a matter of controlling the difference between left and right side torque (which is popularly called "torque vectoring" now) - that can be braking, or driving at any level. Current production vehicles here are required to have stability control, and that is executed mostly with application of individual brakes, although drive power is managed as well. Just as motor vehicle stability control logic is adjusted to accommodate an attached trailer, a trailer could contribute to stabilizing the tow vehicle by only braking or by distributing torque side-to-side appropriately without ever pushing forward on the tow vehicle.

Just providing all of the driving force needed to move the trailer would certainly help with traction, without actually pushing on the tow vehicle; the quoted text does not say anything about pushing. Of course it _could_ actually push, although that would never be needed in any circumstance (because the trailer won't have better tractive force to mass ratio than the tow vehicle unless someone is towing an extremely expensive Airstream with all-wheel-drive using a two-wheel-drive tug ) and would be stupid at any significant speed.



electro wrks said:


> I would call it a pusher trailer because it is actually pushing itself down the road and at least occasionally, for very good rational reasons, pushing the tow vehicle as well.


Pushing itself makes it a powered trailer, of which there have been many over the decades. A pusher trailer would actually have to push the tow vehicle, and in the context of EVs it means a trailer with the primary purpose of pushing... which is certainly not the case here.


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