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-   -   Swooping - technique for hills (https://ecomodder.com/forum/showthread.php/swooping-technique-hills-8518.html)

NeilBlanchard 05-26-2009 10:42 PM

Swooping - technique for hills
 
Hello,

I've been having to try to deal with New England's (small and frequent) hills, and I think that I may have found a technique, that I'll dub "swooping". It is pretty simple really and is pretty much like how you have to bicycle.

As you near the bottom of a downhill, if you are then faced with going up another hill, I (put it back into gear if I have been coasting and) accelerate a little in the last bit and build up some speed to carry me up the hill. Since you have a little more speed, you can keep the use of the accelerator to a minimum and still crest the hill without slowing down traffic.

I used to try and coast up the hill as far as I felt comfortable, and then using the gas, but then you have to accelerate up hill -- which is just about the worst thing you can do for FE... So, swooping definitely works a lot better!

What do you think? How do you minimize FE losses on hills?

dcb 05-27-2009 12:05 AM

Hills are awesome :)

LeanBurninating 05-27-2009 04:47 AM

I do my best to drive as though Im on a roller coaster. Slow at the top, fast at the bottom. I do what I can to always avoid accelerating while going up a hill. I try to maintain speed but near the top I slow down as much as I can (safely). Sounds like you are getting the hang of it.

PaleMelanesian 05-27-2009 11:15 AM

I do exactly the same. I think the key is to hit the incline at a certain rpm. If that requires accelerating before you start the climb, swooping does it. I'll then hold a speed/rpm until I approach the crest and then go into a glide up and over the top. If traffic is light, I'll go as low as 5 mph at the crest. (depending on the following slope, of course)

wagonman76 05-27-2009 01:26 PM

With the massive hills around here there is not much hope for "swooping", but downstate there is a road where I know just what you're talking about. Keep extremely light load down the hill to maintain speed, then add just enough load going up the hill to maintain the speed you need.

I have an automatic so another thing I have to keep in mind is to make it stay in high gear. The mpguino really makes that simple, since anything below 42 mph or 17 instant mpg I know I am going to lose it so I keep it above that. Thankfully the powertrain combination in the Celebrity gives me tons of low end torque so I can climb any highway hill in OD provided I maintain speed.

skyl4rk 05-27-2009 03:44 PM

I frequently use EOC'ing with small hills. One of the goals of EOC is to limit the number and duration of power pulses, so accelerating uphill is a quick way to gain potential energy and get your speed up so you can coast on the downhill, all in one power pulse.

It seems like it is efficient to accelerate going uphill as long as you keep your rpms high enough and don't let the motor dog down. My car seems to like the 2500 rpm +/- 200 range for acceleration, it gets better mpg both on the flats and hills while accelerating in this range.

I generally hit the bottom of a hill at maybe two/thirds or one half cruising speed (cruising speed is 45mph) and accelerate as needed to approach cruising speed and keep rpms where they should be, although I do not necessarily try to reach cruising speed on the hill. This usually means running in 4rth gear so my desired "start motor" speed at the bottom of the hill is about 2300 rpm in 4rth gear (maybe 30 to 35mph, not sure). I don't like to run in 3rd because the mpg is lower, but sometimes you have no choice.

If I don't know what is on the other side or if there is another hill shortly after the first hill, when I approach the top of the hill I shut off the motor to just make it over the hill at a slow speed and then continue the EOC as far as possible. If I know the downhill side is long, I might crest the hill at a higher speed to extend the coast as far as possible but prefer not to exceed cruising speed, even on the downhill run.

Bicycle Bob 05-27-2009 04:27 PM

Some months on a bicycle give a good feel for this. It is seldom a good idea to increase speed past what coasting gives, unless you need that momentum to keep from running out of low gears, on a bike, or going out of lean burn on a car.

I do really wish that MPG meters would regard acceleration and climbing as putting energy into another "tank" rather than spending it immediately.

PaleMelanesian 05-27-2009 04:38 PM

To further clarify my thoughts, before hitting the uphill, I'll accelerate to the point where the engine will power up the hill in its "sweet spot" for power and mpg. That's 35-45 mph in 5th, or 1500-2000 rpm. Where in that range I hit it depends on how long and steep the hill is.

RH77 05-28-2009 12:37 AM

I generally go for target speed + about 5-10mph near the bottom of hills.

Lots of Interstate highways have hills here, so I shoot for 60-65 (for example) and scrub down to 55-60. Based on the hill, speed, load, weather, and payload, there's a pre-determined throttle position to get the job done. It's something that's learned with practice.

There is a point-of-no-return for my automatic if I lose momentum. Sometimes a heavier foot and higher speeds results in a better hill climb -- but avoiding acceleration is key.

There's a great downhill highway run on one of my routes that allows EOC and acceleration beyond 70 downhill! But, what goes down, must go up again...

RH77

Ford Man 05-28-2009 07:07 PM

I coast down any hill that is steep enough to keep my speed where I want it and just as I hit the bottom I accelerate to climb back up. I figure that way I am able to make the best of DFCO and cut pumping losses with the wider throttle opening when climbing. The terrain around here is very hilly also and it seems to be working good for me.


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