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I just did a test in my car and came up with some interesting results.

From what I understand, there is little one can do to hypermile uphill, other than be gentle to the throttle. I have been doing this, and have gotten okay results.

I live at the top of a very large hill, and thus need to climb it every day when returning home. Usually, on the return trip, I average 25 MPG, compared to 28-30 while leaving.
The freeway bit is relatively flat, so the majority of my losses are on that hill.

I decided to test a theory of mine: I am currently consuming around 15MPG up that hill, going about 20MPH (limit is 45). The hill is long, so not only does it take forever to climb but it burns a lot of gas to do so. I wondered what would happen if I gunned the throttle up to 45 and then used momentum to burn off speed until I have to turn onto my street. Well, I tried it, and the results were surprising.

This time on my return trip I averaged 31.4 MPG.

My best guess is that since my car is one tuned with the Bavarian alps in mind, it is geared and designed in such a way that accelerating uphill (well, accelerating at all! :Banane09: ) is what it does best. I probably averaged less than 6MPG under hard acceleration, but it only lasted about 4 seconds and then I let off the throttle and burned off speed in N, as opposed to fighting gravity all the way up at 20MPH. Does that make sense or is it just placebo? :confused:

Hi Kingsly:

___It does given it is a P&G without the ICE being shut down. Maybe not gunned but a high level of load will place you into a sweet spot for either climbing or the flats. The item you do not want to do is hold onto a steady state TPS once you have burned that sub 5-mpg accel as it is a killer :( If it were me, a slowly degrading P&G 50 to 35 to 40 to 25 and so on while climbing in a subdivision like area would be the method I might choose depending on how long a hill it is. If it’s that steep, your exit should include a quick pulse down the drive and FAS the turn and down the hill before even bothering with the ICE until you are as far away from the house as possible anyway … Push it down the drive to get a roll until potential takes over works even better. You will not burn any gas for the trip down the slope if it can be worked out ;)

___Good Luck

___Wayne

I think your results would be even better if you could be at a high enough speed at the bottom of the hill to carry you over the top. There is a hill just over 1/2 mile away from my house that, if I can be at 35 mph as I start going up the hill, I will slow to ~15 mph and get to a slight dowhill and be at 20-25 before I turn a corner and then it's ~.3 miles to my driveway. The coast lasts ~.5 miles or more. What's really cool is that there is a slight downhill just before the uphill stretch. And, if I time everything just right, I can FAS for ~1 mile.:D

...I leave my house and travel on level ground for a block before turning left down a short but steep hill ending in a stop sign. In N down it. Then I'm back in D for the turn onto the main hill and almost immediately into N for the ride all the way down.

I guess my next step is to park in the drive facing out [PP] and just roll all the way to the first stop sign.

As for climbing, I will try your idea for a degrading P&G and report my results.


diamondlarry, my biggest problem is that about halfway up the hill there is a stop sign. I can usually build enough speed on the flat to get me to it with minimal effort, but accelerating from that stop on the hill is the part that kills me. :o

I leave my house and travel on level ground for a block before turning left down a short but steep hill ending in a stop sign. In N down it. Then I'm back in D for the turn onto the main hill and almost immediately into N for the ride all the way down.

I guess my next step is to park in the drive facing out [PP] and just roll all the way to the first stop sign.

As for climbing, I will try your idea for a degrading P&G and report my results.


diamondlarry, my biggest problem is that about halfway up the hill there is a stop sign. I can usually build enough speed on the flat to get me to it with minimal effort, but accelerating from that stop on the hill is the part that kills me. :o

Ouch! :(

Yeah, I know... :(

It's kind of a pointless sign too because the only time that intersection has any traffic is during summer holidays (it leads to a lake) and then the police are out there directing traffic anyway! :mad:

Perhaps you can figure out what your optimal RPM and load
are in general, up a similar slope or even on the flat,
and then try to stay in that range during your forced
restart up the hill. After doing all the right load/timing
things to reach the stop sign in the first place, of course.
Chances are that your non-hybrid with the larger powerplant
is more efficient at higher "alpine-like" loads...
.
_H*

Is there a way to easily find out the optimum RPM and load (ie. a table provided by the manufacturer) or do I have to calculate them? If so, then how?

Hi Kingsly:

___This is how I approach that scenario given the OEM’s data is junk for what we do with our vehicles. Warm her up first of course then change to various pulse rates within a similar speed range or band by checking the aFCD just before the beginning of reinitiating each pulse. Once you have got some good numbers there start changing the ranges to see what works best …

___For example, let us say a 60 - 70% max load or 8 - 15 mpg Pulse from 20 - 40 mph yields 42 mpg after 1 cycle. On the next cycle try a 70 - 80% load or 6 - 12 mpg Pulse from 20 - 40 mph and find what she yields and so on. As you continue to add miles, your pulses will begin to average so do not expect exacting results unless you reset the aFCD before each pulse. Compare the previous yield to the next and keep adjusting to increase or plateau your yield from pulse to pulse on a relatively flat roadway with nobody around so as to make each cycle repeatable … After you have a rate down, start working on the range. It will not take but 30 minutes to come up with a good estimate for how hard you should take her on a given pulse over a given speed range to improve efficiency. I can tell you that pulse rates and bands change with temperature just as they do with road conditions, hills and wind so get as much done in a single day as you can and place the results in the back of your mind. 50 - 60 degree temps, I can run the tach to such and such before a short shift to the next gear and run her up to such and such speed before I begin my Glide. It sounds like “Weird Science” mixed with some “Black Magic” but determining efficiency in a non-steady-state environment is where the art of hypermiling comes in. It may take a while before you figure it all out for a given section of roadway but using the method above works pretty well for me? Hopefully others will chime in with there own and possibly better methods also? Be wary of the hard science as it can con you into a tight set of rules when in fact the artists continually change with conditions in an attempt to keep that aFCD as high as reasonably achievable … The Artists usually come back with higher FE averages for whatever reason? You will know when you are in the hunt when we start seeing you post 40 - 45 + mpg segments in your Beemer. At that point, you are probably getting very very close ;)

___Good Luck

___Wayne