Sustained Hill Climb Strategy
 

My house is on top of a hill. It is great leaving, I can just leave it in gear and coast down the hill to warm up my engine without sacrificing gas consumption. On the way home its a nightmare, I get about 13 mpgs over the 1.6 miles. It just murders my average mpgs, and today I lost .5 mpgs on a 225 mile tank :mad:

The hill is steep and curvy enough that I can't get out of 3rd gear without bogging way down, and the speed limit is 30 and then 40. I have tried going 30 the whole way, I have tried going 40 the whole way and my mpgs are stuck. Do i just need to accept defeat from gravity or is the a hypermiling technique that might net me even a little improvement.

This is a topographic map of my route from the bottom to top of the hill, courtesy of Google, it is about a 750 ft climb.
http://i1152.photobucket.com/albums/...psb6abefe7.png

I regularly drive a route of about 60 miles with a net elevation change of 800 feet. My trip average mileage is about 5 MPG higher downhill than uphill.

This thread is a discussion on driving uphill: http://ecomodder.com/forum/showthrea...ear-23957.html

Bottom line is that it takes a lot of fuel to climb 750 feet.

I think it's time to move.

Have you tried hitting it at a higher speed, like 60+ and then winding it down as you go up?

If you can get away with it, maybe if you tried 3rd gear at a lower speed - however low you can take it without it bogging down. Whenever I have to downshift to go up a sustained hill, I'll drop the speed down to lower the revs. Seems to help - not much, but a little. So maybe try it at 25? Or even 20 if your car can pull it in 3rd. ???

lighter car, lighten the load, don't gas up on the way home, use the washroom at work,

Take a guess at bsfc peak rpm and load (say 2300 rpm and 3/4 throttle) and keep the car there with the gear selector (disregard the speed limit at your own risk).

Coast the very last part.

I don't think it is so bad.
So you just get 13 mpg uphill, but infinite mpg down, and you warm up the engine to boot.
The whole stretch up and down combined gives you 26 mpg overall.
Considering the weight of your car and the cold start, that is quite good actually.

Maybe instead of warming your engine downhill, you EOC. Another idea, strange and the opposite of Pulse & Glide, you EOC until you are doing the max speed for the road, then 3rd, 2nd, 1st, EOC to terminal speed, 3rd, 2nd, 1st.

It doesn't really help with your problem, but as mentioned, it seems like you have covered the basics on getting up their as efficiently as possible. And it makes sense you can't start out at 60 and coast it out if the curves can't handle it, especially if it starts at 30. I have not found a good way to get up extended hills without building speed and letting it slowly fall off.

The good.
The balance.
The truth.

I live on a hill also. My 120+ mile commute MPGs will be 40 at the bottom of the hill, and under 39 at the top. Yes, it's annoying to watch those hard-won tenths of MPG tick away. But the fact is that I would not have been at 40MPG at the beginning of the climb had I not gone down the hill in the first place.

So: smile, shrug your shoulders, and enjoy the view.

What goes up must come down... and vice versa. You don't need to admit defeat so much as admit that there's a hard stretch in your commute. Other than weight reduction, I can't suggest anything.

thanks for all the responses, you have confirmed what i suspected... that gravity is a b*tch and there isn't much that can be done about it. lol

You could always fake car problems (hood up, flashers on) and see how many offers you get to tow you to the top. :-P

So where P&G, EOC and DWL fail, give AAA a try! :D

By driving up the hill you add a lot of potential energy by moving the mass of your car further away from the earths core. It's not lost; just converted from fuel to height.
Thats the way with physics; the law of gravity is strictly implied and perpetraters will be brought down infallably :p

A typical car engine will perform more efficiently under a heavy load than under a very light load.
Going down it uses no fuel at all. With the right incline you could even be better off than driving on flat ground; a natural P&G opportunity.
As your engine already runs efficiently up that hill there is no real room for improvement, except some weight shedding. It ain't broken, so don't fix it.

Wouldn't use EOC going down a mountain road; that's when I would not like to suddenly lose PS or brake support. The economy going downhill will always be impressive, even if the engine does not shut off fuel intake completely.

That and I should stop along the side of the road once a week acting like i am out of gas and see how much free gas I can score!

Well said. I feel the same way about EOC down the hill, its just not safe.

small update.

i tried taking the hill with the goal of 15+ mpgs and was able to DWL right around there at 25 mph until somebody got behind me and i had to speed up to 30, where i got about 12 mpgs. near the end of the hill is a short downhill followed by an uphill and i was able to accelerate to 45 and get into 4th during that stretch and pull 20 mpgs for about 1/4 mile before i EOCed the last 1/8th mile home.

Definitely an improvement but am going to keep trying new things!

The difference between EOC and warming it up coming down will be pretty insignificant compared to the high burn going up. By your description of low speed limit, high grade and lots of turns means that some sort of braking will be necessary, likely best to let that braking action warm the engine, power your steering and brakes rather than heat your pads and disks. Good call.

Is there any way you can go just a bit faster to keep it in a higher gear for a greater % of the trip up (perhaps dropping to 3rd for a little boost then DWL in 4th where you can) or is it steep enough that it just won't pull it?

I am not sure what type of instrumentation you have but watch your open and closed loop indicator, when loaded like that it is pretty easy to drop into open loop.


OOOh take advantage of up slope winds by having a kite boarder in the bed of your truck help you up the hill.

i am using an ultragauge, i just installed it, and am not sure about an open or closed loop indicator.

i will look into it.

Little ring on the top right of the screen. When it is open (broken) the computer is running on the fuel map (which tends to be on the rich side). When closed it is consulting the O2 sensor.

Look for another way up/down. Does 30 go up the slope to the west? It's probably straighter and flatter than your winding road.

yes and its only 3.5 miles longer lol

At what fuel consumption? Try it and calculate how much fuel each route uses. It might actually use less.

Whoa whoa whoa. Are you seriously recommending driving further just to save fuel? What does that make all of the other costs associated with driving a mile in an automobile - chopped liver?

That sounds like a hell-of-a-hill. I have a smaller but significant one on my commute. I experimented with a strategy. Here is my test: http://ecomodder.com/forum/showthrea...tml#post252933

But your hill sounds much more difficult.

if the fuel savings are high enough and the increase in daily mileage small enough % of total mileage driven then they may be chopped liver. Insurance, a portion of the depreciation and car payments are time rather than mileage. Oil is partly a time based expense as well.

After time, fuel is the next highest cost per mile if you're buying gas.

Pale,

Very crafty idea!

Several years back I was talking with someone from the office at work, and they were inquiring why I take a longer trek on the backroads to a town that he lives in.

My response was that I get about 75 mpg on the highway and 120 mpg going slower on the backroads. Well, then he said "yeah, but now your driving 4 miles longer, and thus burning more fuel".

Well, it works out that taking the longer route AND maintaining higher MPG actually *saves* fuel for me.

Jim.

I've been dodging lots of freeways lately lol. For me: It adds an insignificant amount of time to driving, it's more enjoyable, and saves plenty of fuel to justify the extra time spent/miles driven.

I have driven up hwy 30 on that grade. I think it may save some fuel if you avoid the slow in-town stuff in Rainier. If you can conserve some momentum and drive up the hwy 30 grade in 5th gear (55 speed limit right?), it may offset the longer route. Plus, it looks like you can somewhat coast or P&G along the ridge when you get onto meserve rd.

Good luck!

Afterthought: If you coast down hwy 30 it should offset the longer uphill. Thats the other way to get better mpg: more miles on the same fuel. :p

You may already be doing this, but I suggest that you keep your speed as constant as possible,if necessary,accelerate at the easiest points possible (smallest inclines) , minimize braking, take turns wide when safe, and make all passengers get out and walk up the hill. Ha ha! Or have you tried taking Old Hwy 30 (Old Rainier Rd) to Meserve Rd? It's a bit further,but it looks less steep on the map.

Old Rainier is the windiest and bumpiest road in the area, no way i am going up that thing lol