This is a CS-mode question that comes up when thinking about the recent GM articles about "summer electric road trips".
One thing I don't entirely understand about the Volt yet and want to before jumping in and buying one.
Say you're on a flat highway (ie. Iowa) driving at 55mph and viewing corn fields for hours on end. Let's say demand to push the car at this speed is 17 horsepower. If the ICE is running at say 1/2 speed or 3/4 speed, isn't it putting out more hp than 17? In CS-mode, we're maintaining the SOC but shouldn't we be able to be charging and increasing SOC (keeping in mind charging losses from crankshaft to battery charger circuits)? If ICE runs say 30hp while driving is drawing 17hp from the batteries, wouldn't the excess ICE output be "bankable" into the battery without requiring a specific Mountain Mode setting?
My thinking is if the CS-mode ICE output is higher than needed to turn the wheels, we should see an ever-increasing SOC so that after a nice flat moderate-speed drive, SOC should be nearing full. Or, does the ICE shut down after some time so as to be back on CD-mode for a while (basically a set-point range where if SOC rises above 40%, run on battery only and if below 30% power-on the ICE and go into CS-mode). In addition, after a climb if a 3-mile hill in CS-mode, going down the other side in L should put a few kWh into the battery as well and should turn off the ICE for a while, correct?
Just the efficiency mind in me thinking "every excess horsepower should be put into the battery".