Can this possibly be correct? Are you sure this describes a system for 18-wheelers, rather than something closer to small to medium "box trucks"?
Michel Jullian wrote: > Excerpts: > Eaton's hybrid system for city delivery applications uses a parallel, > pre-transmission design with Eaton's Fuller UltraShift automated > transmission. Primary components are the Hybrid Drive Unit (HDU), > which combines a clutch, a 44 kW/420 Nm motor/generator... 44 kW is 59 HP, assuming perfect efficiency. For a truck engine in a large truck, we're normally looking at something like 400 or 500 HP, maybe more for a turbo diesel -- in other words, the power plant is usually around 10 times the value quoted there. A 44 kW engine would be appropriate for a car, but not for a semi. The torque isn't so awful -- if I got it right, 420 Nm converts to about 300 ft-lb, which is only down by a factor of a few from what I'd expect to see. This would all seem to imply that the ICE is doing the lion's share of the work during acceleration, and is probably doing a large part of the work during cruising as well. Since a braking system is typically more "powerful" than the drive system (measuring "power" with the sign flipped here), and current-generation charging systems typically can't push energy into the batteries all that much faster than the engine can pull it out, this also suggests that regen brakes on these trucks aren't going to be recapturing more than a small fraction of the energy. How can this rig possibly be sufficient to make any kind of dent in the mileage?
