Inclinometer for coasting
 

I'm trying to figure out a real-time method to determine the down slopes that my car is driving on. On my usual drives, I've been able to find the downhills where I can maintain my cruising speed through trial and error when I let out the clutch. But when driving on unfamiliar roads, except for the obvious downhills, it can sometimes be difficult to tell when I'm do a downhill steep enough to effectively coast (my car can maintain 55mph on a 2% downhill). And sometimes the lay of the land can disguise the fact that I am actually going downhill.

I've tried mounting an RV style curved bubble gauge, but it is so sensitive that it overlays my gradual acceleration/decceleration while coasting on top of the slope of the road. So when I see a -2 degree reading, I can't tell whether its reading a constaint velocity on a 2 degree downslope or a gradual decelleration on a flat road. An aircraft gyro-based artificial horizon would work great, but at over $1000, is much too expensive. An aircraft vertical speed indicator (about $200) would also work, but its reading is speed dependant. Any ideas for an inclinometer that is unaffected by minor vehicle changes in speed?

I've contemplated trying to find some way to do exactly what you are describing. The only inexpensive idea I have is to hang plum bob from the rear view mirror, so that it has a long length and is hopefully over some area down on the console, that I can mark or something.

It seems to me like their ought to be a better way to do this and if you come up with something I'd be really interested.

Maybe a gyroscopic pitch indicator (inertial or interferometer-based).

how about a string with a weight attached?

On the Level???
 

Ironic this would come up today. 3-4 days ago I started something I haven't finished. Not much to it, may try it tomorrow. Bottle is about 8 in. long, drawn line 6 in. long. W/S washer fluid with a little food coloring added. I plan to fasten it to passenger window forward as much as possible. I have 6 in. strips of Velcro to stick to window and bottle. White Velcro should give a good backdrop for visibility of the line. I will saw a thin wooden wedge on a slight angle to use under the bottle on top of the window sill to level and stabilize. To set bottle level I will have to get the car on a level surface.

I am hoping this will help me recognize level ground. It is disappointing to think I am on level ground, accelerate, shutoff to coast and have the car immediately slow down because it is uphill. I have wasted the acceleration and got nothing back. Don't know if this will suit what you need but here it is. I rotated the bottle to show the line better. Pic not great, reflections, and half dark but gives the idea. Cost: about 50 cents for Velcro.

https://aycu32.webshots.com/image/911...0471831_rs.jpg

Basjoos,

how are you getting 23mpg in your truck is it a 4.2 liter? I have a 99' f-150 4.2 MT short bed super cab I can barely get 17mpg. Today just got narrow tires on it I hope to see an improvement LT225/75/16 they can handle over 80psi and are supose to carry a heavier load. And yours is a 4x4 that is amazing

Go on E-bay and search for inclinometer. Some used ones from old Toyota, Nissan and Mitsu trucks can be found. Many will show front to back and side to side pitch.

Wayne

I ws just going to suggest this same route. there are several Toyota 4 Runners in my old junkyard that have the inclinometer still in them. they probably could be had for cheap as well.

What? No adjustments for head/tail wind? Nothing to compensate for desired speed?
A 2% slope may be fine at 45 mph, but will require fuel addition at 65 mph.

Why not a simple strain gauge measuring the torque load on the motor mount? A simple string tied to the engine, run back through the firewall and fastened by a spring will be pulled as the load on the engine increases. Make a mark on the string and a corresponding mark on some fixed background with the engine off. That's zero torque. Any time the marks line up while driving indicate that the engine is not adding torque to the wheels.
Oh, and not subject to G force (or freezing temperatures) either.

theclencher -

That's what I was thinking, but oil didn't occur to me. I was thinking of those transparent plastic encased "blocks of goo" that have little dolphins and such floating around in them. A little motor makes them rock back and forth so that it looks like slow-mo ocean waves. Probably would go bad in the summer, though.

My wife suggested a level from a hardware store. That's easy for me to test, but would probably still react "too fast" for basjoos purposes.

Here's just one of very many e-bay solutions :

79 9007 TOYOTA TURBO 4RUNNER TRUCK 4X4 INCLINOMETER
$15 + $10 Shipping and Handling
https://cgi.ebay.com/ebaymotors/79-90...QQcmdZViewItem

CarloSW2

Here's a thought. Just get a piece of clear vinyl 1/4 inch tubing, about 12 feet long. You can fill it about 1/2 full of dark colored water. Then use a coupler to join the two end's together. Then you just run it along the inside door pillar, back to the back of the passenger compartment, down to the floor, back to the front, up to the front door pillar.

The distance between the front of the tube and the back gives it a larger differential in terms of the height of the liquid in the tube and it would give a pretty fine degree of sensitivity.

Get a digital Level used in wood working.

I think Lug Nut has the right idea. Why not just go with either a big dial vaccum gauge or digital vaccum gauge? With the SG I just leave it on MAP and it's great for showing the slightest imputs to maintain speed with slope. Using it and your eye's you can use it for just what your talking about.

Its a V6 MT longbed 4X4. Basically I drive it in the same manner as I do my Civic (of course it doesn't coast worth a darn, so I can only use of few of the downhill coasts I can use with my Civic). I only do ICE off coasts if there is no traffic around and the road is fairly straight. The only mods I have done to it so far is to air the tires up to 50psi and to install an almost full grill block. 23 mpg isn't the best I have been able to get from it. Last summer I got 26mpg in local (mostly under 45mph) driving. I plan to do some underbody panellng on it this spring and hopefully get it up into the upper 20's on a regular basis this summer.

I don't think any of the plumb bob, bubble level, 4x4 inclinometers, or other gravity based sensing systems will work since they can't distinguish between the gravitational pull of the earth and the "gravitational" pull from changes in the car's velocity. Even changing to a thicker liquid is not going to have any effect in trying to avoid detecting the continuous gradual decceleration of coasting on a flat road.

Silveredwings' gyroscopic pitch indicator would work, but is not inexpensive, the cheapest device of this type I could find, the E-GYRO, was $500.

Lug Nut's string "torque-o-meter" or zpiloto's vacuum gauge would be more likely to work since they could detect the engine's "null point", where it is not either driving forward or holding back on the wheels. I'll investigate my car's engine compartment to see how I can implement one or the other of these two suggestions.