Re: tips for driving through mountains???
Originally Posted by Adam_HybridCivic
Yeah I have a tip if it will help. On a downhill pass try and speed up maybe even as high as 20 MPH over the speed limit. Then on the way back up hill release pressure on the gas and let your momentum get you up the hill with some assist from the accelerator. You will lose speed on the way up but the idea is to return to speed limit speed (or your previous crusing speed) with out using much power up the hill. During this process may battery recharges fast as well. Over time and with practice you will learn to judge the size of an up comming hill and adjust your speed accordingly.
If you are on a constat up hill, in my opinion there is not much you can do but grin and bear it and make it up on the way back down. Also, at highway speeds, coasting to get extra speed is going to be a diminishing return as there is going to be rapidly increasing drag, so you're probably better off filling the pack to the point where you won't need force-charging later on. This is also the reason why going up a steep grade and down a gradual grade is moer fuel-efficient than the other way around. On gentler grades, it's more efficient to coast than to charge (as there are efficiency losses involved with charging the pack), since the grade is just sufficient to hold a steady legal speed rather than accelerate you past legal speeds. I live on a hill where I must go up 850 vertical feet, then back down the backside 150 feet when coming home. (This actually kills my overall mileage compared to living at the bottom of the hill by more than 10 percent, thanks to stop signs and low speed limits) so I've got some experience with this type of climbing as well. The key when on the bottom is to pick up speed on the flat part before going into it. If the pack is not topped off, it may be a good idea to drop into "S" when initially accelerating to save some battery power. This will use more gas at first but prevent going into forced charging later on. Then I hold a steady throttle position and let my speed slowly bleed off until I hit each stopsign (I roll up to these rather than braking). I also try to use assist only when accelerating or going up the steepest sections, on parts with more of a gradual grade, I'll feather the throttle until assist backs off, again to prevent the pack from getting low and force-charging near the top. Also, on the way down, regen braking is not enough to hold my speed, so another idea (if it's hot out) is to run max AC on the coldest setting the entire way down. This will make the cabin very cold, and provide useful braking in the process. It also means the A/C won't need to do as much work later on to keep the cabin at a set temperature. |
Re: tips for driving through mountains???
Originally Posted by Packrat
I have the same kind of outcome as ElanC--after a mile or so of uphill, there is no assist--the ICE revs to 3500rpm and mpg tanks. After a mile or so of downhill, there is no regen, but at least I'm not burning gas. The battery is too small to deal with long grades like that. I don't think it's a design flaw, it's just a tradeoff based on current technical limitations. Most people wouldn't see a benefit from having twice the battery back there. In fact, it might be a liability due to the weight.
I suspect that it also may have to do with how quickly the batteries are drawn down. Just as regen is prevented when the batteries are too cold, assist may be cut off when the batteries are drained very quickly because the batteries over-heat. Just a theory... |
Re: tips for driving through mountains???
Originally Posted by ElanC
I agree that the design is meant for the average driver and not for us hill people. But the frustrating thing is that the IMA never allows the charge level to go below 4 bars. Is your experience any different in that regard?
I suspect that it also may have to do with how quickly the batteries are drawn down. Just as regen is prevented when the batteries are too cold, assist may be cut off when the batteries are drained very quickly because the batteries over-heat. Just a theory... So this morning (keep in mind I've only had the car a week) I turned it on, started rolling down the hill, put it in neutral, turned the ICE off, and coasted the rest of the way to the stop sign at the bottom. I'm trying to figure out whether this will be a better strategy (given that it presumably also delays the car's warming up). Any thoughts? |
Re: tips for driving through mountains???
Originally Posted by samajhna
So this morning (keep in mind I've only had the car a week) I turned it on, started rolling down the hill, put it in neutral, turned the ICE off, and coasted the rest of the way to the stop sign at the bottom. I'm trying to figure out whether this will be a better strategy (given that it presumably also delays the car's warming up). Any thoughts? |
Re: tips for driving through mountains???
Originally Posted by ElanC
I agree that the design is meant for the average driver and not for us hill people. But the frustrating thing is that the IMA never allows the charge level to go below 4 bars. Is your experience any different in that regard?
I suspect that it also may have to do with how quickly the batteries are drawn down. Just as regen is prevented when the batteries are too cold, assist may be cut off when the batteries are drained very quickly because the batteries over-heat. Just a theory... Packrat |
Re: tips for driving through mountains???
Originally Posted by ElanC
I agree that the design is meant for the average driver and not for us hill people. But the frustrating thing is that the IMA never allows the charge level to go below 4 bars. Is your experience any different in that regard?
I suspect that it also may have to do with how quickly the batteries are drawn down. Just as regen is prevented when the batteries are too cold, assist may be cut off when the batteries are drained very quickly because the batteries over-heat. Just a theory... Packrat |
Re: tips for driving through mountains???
Originally Posted by ElanC
I don't understand what problem you're trying to solve, and why.
... Has anyone else seen the SOC go below four bars while climbing a hill? My problem is that the pack went from full charge down to 4 bars daily. My pack never went below 4 either. The wide pack swings were rumored to decrease battery life if they occurred frequently. So I experimented with driving that would reduce the pack swings. After your post I went reading some more on the NiMH batteries used in Hybrid cars, and I think they are rated for 100k small cycles (small like 10% swings). That is ten times the cycle rating of a normal NiMH battery at 1000 full cycles. I found a picture of the HCH-I pack on howstuffworks.com, and found that they are specially made by Panasonic. I also toyed with the idea of putting a bigger battery pack in my car. I found some 11000 mah NiMH D cells, and nearly doubled capacity sounded way cool, but it just wasn't that easy. :-) |
Re: tips for driving through mountains???
Originally Posted by kmh3
I also toyed with the idea of putting a bigger battery pack in my car.
I found some 11000 mah NiMH D cells, and nearly doubled capacity sounded way cool, but it just wasn't that easy. :-) |
Re: tips for driving through mountains???
Originally Posted by samajhna
I have the same experience, living as I do midway up a hill... I usually go down the hill in the morning when the engine is cold, so I get no regen at all for that stretch which is just galling when I spent so much assist power getting up it the previous evening.
So this morning (keep in mind I've only had the car a week) I turned it on, started rolling down the hill, put it in neutral, turned the ICE off, and coasted the rest of the way to the stop sign at the bottom. I'm trying to figure out whether this will be a better strategy (given that it presumably also delays the car's warming up). Any thoughts? As for me, since I need to go up and over my hill to get home, that means I have significantly climbing to begin with cold. By the time I'm rolling down the big part of the hill, the engine is already warmed up enough that I can charge the whole way down -- I'm usually just topping off as I reach the bottom to get on the freeway. |
Re: tips for driving through mountains???
Originally Posted by coyote
But be careful.
I have a friend who drives slowly to max his normal MPG, and then uses this "speed up downhill" technique to max his hilly MPG. And he got a ticket for speeding. :embarass: Years and years of driving regular without a ticket. Now he has a hybrid and drives much slower -- and he gets a ticket for speeding. Go figure! |
All times are GMT -7. The time now is 11:16 PM. |
© 2024 MH Sub I, LLC dba Internet Brands