pure copper density at 9000 kg/m3, wire diameter assumed at 1mm, length at 3000 m (1.8 mi, approx) gives 21 kg, approximately 46 lb. math checks out.
> the company claims a 20 percent savings in material costs and 15 percent reduction in its carbon footprint between Gen 1 and Gen 2.
surely this is not just due to the reduction of copper. copper is around 10 USD/kg at bulk.
now let's see if we can address the copper length number. can 1.6 mi (< 3000 m) of copper be saved from wiring alone?
The car dimensions are 2m x 5m. That means, in the worst case, two ECUs placed at opposite ends will need 5m of wire (half of perimeter). There were 17 ECUs originally. Call it n = 20, and if we wire dense (in the graph sense), we get n^2 = 400. So, in the absolute worst case, the densest possible graph would have had 5m x 400 = 2000 m of wire. The claimed wire saving is significantly (but not by an order of magnitude) larger than this. I would say this passes the smell test (albeit barely), but original wiring must have been truly inefficient.
spydum
maybe i missed in your estimate, but most circuits need more than one wire?
hn72774
In a vehicle, the chassis is the negative wire in the circuit.
AlotOfReading
The vast majority of automotive buses use differential signaling over multiple conductors for EMI reasons. The only common exception is LIN and maybe SWCAN if we're exceedingly generous with our definition of "common".
caleblloyd
I didn’t completely follow either but I think the n^2 = 400 worked out to 20 ECUs each with 20 wires
> 1.6 miles and 44 pounds
pure copper density at 9000 kg/m3, wire diameter assumed at 1mm, length at 3000 m (1.8 mi, approx) gives 21 kg, approximately 46 lb. math checks out.
> the company claims a 20 percent savings in material costs and 15 percent reduction in its carbon footprint between Gen 1 and Gen 2.
surely this is not just due to the reduction of copper. copper is around 10 USD/kg at bulk.
now let's see if we can address the copper length number. can 1.6 mi (< 3000 m) of copper be saved from wiring alone?
The car dimensions are 2m x 5m. That means, in the worst case, two ECUs placed at opposite ends will need 5m of wire (half of perimeter). There were 17 ECUs originally. Call it n = 20, and if we wire dense (in the graph sense), we get n^2 = 400. So, in the absolute worst case, the densest possible graph would have had 5m x 400 = 2000 m of wire. The claimed wire saving is significantly (but not by an order of magnitude) larger than this. I would say this passes the smell test (albeit barely), but original wiring must have been truly inefficient.