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Old 04-15-2012, 01:34 AM   #63 (permalink)
redpoint5
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Quote:
Originally Posted by jtbo View Post
... works well when there are continuously hills, but if there is just one hill it can be different story.

... how much power one would need to stay at hill?

Even with lowest gear at steep hill, one needs to ask more power from engine so I doubt that it is just 1hp for staying on hill, even 10hp might be bit too little? ...but it is quite a lot of force that 1000kg or more weighting vehicle is making with gravity at 5% slope, I think it is possible to calculate how much power is actually needed.
For the purposes of my example, imagine a very long and continuous hill. I'm used to driving up mountains around here, and it's not uncommon to travel many miles of continuous 5% grade. I can engine-off coast for about 10 miles when I'm descending Mt. Hood!

The 1hp example used above was an arbitrary number I choose for ease of math. Of course, the amount of power required depends on the weight of the vehicle and the angle of the slope. Calculating these requirements is possible, but difficult considering the varying slopes and weights of vehicles. I'd be curious to know the power requirement to hold a 3000lb vehicle on a 5% slope, as a baseline.

My Subaru Legacy averaged 27mpg, but on days that I traveled to the mountains, I could achieve 33mpg. I would drive in the highest gear possible while giving about 85% throttle.
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