atreis wrote:
valhalla360 wrote:
For hill climbing, the low end torque won't help significantly. Climbing a hill, you should select a gear that keeps the engine in a range where it produces peak torque/HP.
Where the low end torque helps is in stop & go traffic starting from a standstill where the diesel has to wind up to get into it's peak torque range before it puts out it's rated torque.
More importantly, to provide 250hp for 30min would require a battery bank of around 1.5tons with standard deep cycle and 3/4 of a ton if you go with much more expensive lithium batteries.
Quite true (although no one in their right mind would suggest using Pb batteries in a modern hybrid system). Of course, after spending 20 minutes using batteries to get extra power while climbing the hill, you then recharge them on the downside. What's the advantage? You can then use a smaller, more efficient, engine. (If they do run out, you just climb slower.)
It's hard to say exactly how many HP I'm using when climbing (there's no meter in the car for that) but I suspect it's usually substantially less than the engine's rated maximum of 266hp.
The only time I really have to wind up the engine is when climbing a 9.5 percent grade with the trailer. I do that climb once a year and it only takes about 5 minutes.
Did you miss the part about the drastically more expensive lithium batteries still eating up 1500lb of payload? This likely pushes you into buying a step up in truck size for the same trailer.
If the batteries die before reaching the top, you only keep moving if you have a low enough gear ratio, which they likely wouldn't supply if they expect to have the extra HP from the electric motors to cover really heavy load situations. Also with 1/2 the HP, even if you have a low enough gear ratio, you are going to see a drastic reduction in available speed.
In theory, you could sit on the shoulder with the engine charging the batteries for a while...of course that comes with a big tradeoff. If you make the charging system big enough to recharge the fully depleted batteries in a short time, it adds greatly to cost, weight and it eats into the power normally available directly off the diesel. If you put in something more modest, it may take a few hours to top up the batteries.
Where a hybrid pickup could make sense is for the typical grocery getter who will never tow anything significant. If you never plan to haul more than 1000 lbs and tow more than 2-3000lbs, a 100hp diesel with a 100hp electric would be doable with a typical 1/2ton and 500-1000lb of lithium batteries. It would operate similar to the volt, where commuting most days it would run on pure electric and only bring the diesel online for long trips or if you need extra power. The problem is marketing as most grocery getter buyers don't want to admit that is why they have a pickup.
