GPS enhanced cruise control?

[BBR]

I was driving down the interstate a while back thinking about roadways, gas mileage, and how my vehicle, while the cruise control is on, responds to changes in the elevation of the roadway.

I realized the cruise control has a passive response to changes in grade, and I typically have an active response. I see the hill, and anticipate the vehicle will slow and increase throttle to compensate. With the cruise on, the vehicle has no way to anticipate the hill, so it finds itself 'playing catch up' to maintain the preset speed. This means the vehicle must use more throttle input (and more fuel) to catch back up.

With the proliferation of GPS technology in today's new vehicles, it looks like the cruise and the GPS could be integrated to allow the vehicle to anticipate these changes in grade, gradually increase vehicle speed (within reason lol) to minimize this 'catch up' time.

Anyway, that's BBR's deep thinking for the day. ;D

[ponchoman]

Re: GPS enhanced cruise control?

I'd say it's a good idea except for one thing. People often don't realize the accuracy loss that GPS creates when you're talking about elevation changes. It's the same reason that GPS Speedos have accuracy issues once you get in hilly terrain, mountains, and where line of sight to the sats is problematic.

You need at least 3 good satellite fixes which provide excellent almanac data for a 2D fix (long/lat). The more sats, the better the accuracy. However, introducing elevation creates more complexity. You need at least n+1 fixes in order to get elevation changes, and they often lag. At Bonneville for example - elevation changes will work great. In the valleys between the Bighorn and Rocky mtn ranges, not so good.

I think another thing is that my experience with cruise control is that newer vehicles don't seem to "lag" much. Some of it may coincidentally tied into the discussion about throttle by wire. I think that newer FI systems with potentiometer based throttles may "spool up" even quicker. I know my current newer vehicles maintain speed up and down hills within 1mph very well (and I live in a hilly area).

It is a real interesting idea. BBR, what vehicles do you see the most "problem" with? Does anyone else experience a difference (improvement) in cruise control consistency even over different terrain of newer vehicles vs older vehicles?

[HillbillySailor]

Re: GPS enhanced cruise control?

I was driving down the interstate a while back thinking about roadways, gas mileage, and how my vehicle, while the cruise control is on, responds to changes in the elevation of the roadway.

I realized the cruise control has a passive response to changes in grade, and I typically have an active response. I see the hill, and anticipate the vehicle will slow and increase throttle to compensate. With the cruise on, the vehicle has no way to anticipate the hill, so it finds itself 'playing catch up' to maintain the preset speed. This means the vehicle must use more throttle input (and more fuel) to catch back up.

With the proliferation of GPS technology in today's new vehicles, it looks like the cruise and the GPS could be integrated to allow the vehicle to anticipate these changes in grade, gradually increase vehicle speed (within reason lol) to minimize this 'catch up' time.

Anyway, that's BBR's deep thinking for the day. ;D

With the developement of "self drive" cars in the works, I could see them including GPS as an integral part of cruise control and location mapping (to back up the sensors being built into the roads). The only problem I forsee with that is the accuracy of some GPS maps. On my TomTom, I've been driving down a road that had been buit 6 months ago but the map hadn't been updated. As such, TomTom showed me driving through a field! Or in other cases, well established (but were dirt) roads were not included at all. Before we could rely on something like that for anything, the GPS maps would have to be updated first.

[Loren]

Re: GPS enhanced cruise control?

GPS could be used as an assist to cruise control to anticipate changes in elevation. A couple years ago I read an article about a company that had minivans driving every road in the country, photographing out each side and front/back every few yards and recording other things such as elevation. This was all to go into a database which could be sold. Among the hoped-for uses was for enhanced cruise control where if a hill was coming up the vehicle would be ready...this was thought to be particularily useful for commercial trucks and they had it figured out how much fuel could be saved nationwide each day if all trucks had it.

I don't know whatever became of it...I suppose a little research would be called for. Anyhow, I'm just adding to the thought.

[BBR]

Re: GPS enhanced cruise control?

Boo Loren, I thought I was on to a new idea! lol dagnabbit! I was gonna be a millionaire!

A a land surveyor, I completely understand the limitations of non-triangulated gps elevations. Single receiver GPS is fairly good for horizontal locations, but very very weak in determining elevations. This is because GPS uses time differentials to calculate distance. As technology advances however, it will only get better.

Anyway, my original idea was really to use the vehicle's gps to correlate the vehicle's global postition to a pre-programmed digital elevation model (or even a simple digital centerline profile) of the highway. The accuracy would not need to be all that great, +/- 2 feet would be fine. Those types of accuracy are easily attainable from DEMs created from aerial mapping, many of which already exist.

My intent is more for interstate/divided highway use, when you will have the cruise control on. Not back roads stuff. It would not be really any different from using a regular cruise control, it would just be smarter.

Poncho, I cannot pin point specific vehicles, I just know when going up a steep inclines on the highway, the vehicle will initially slow then try to catch up. This is very evident on older TBC (throttle by cable) vehicles where you can feel the cruise mat the throttle and try to play catch up.

;D

[BBR]

Re: GPS enhanced cruise control?

DAMMIT!!!

http://gpsobsessed.com/freightliner-trucks-get-navteq-enabled-predictive-cruise-control/

[IRONHEAD]

Re: GPS enhanced cruise control?

is it readly that hard to move your foot..

[dieselgeek]

Re: GPS enhanced cruise control?

fail? not quite!! it's a good idea.

I worked on a project (that seems to be dying from lack of investor funds) where they considered doing the same thing. Only, they would use the GPS info to decide when to start charging batteries in a hybrid powertrain.

One issue is, it must involve more driver input than just "cruise control activate" - the car has to be travelling along a programmed GPS route, kinda like setting up an autopilot or EFIS system, so it knows where you intend to drive. Making the driver more like a pilot (more involvement in route planning).

Otherwise, it would be a good idea IMO.

[BBR]

Re: GPS enhanced cruise control?

No I was thinking more of 'if then' programming statements.

IF you are on a mapped road and IF you have the cruise on, THEN the enhancement is active.

[IRONHEAD]

Re: GPS enhanced cruise control?

why not just add the speaking software, so you can say to the car. hill coming..
you can have some cars dial a phone. pick mp3s for you. etc ..
why not this.. and it be better than a gps map that can be off...

[ponchoman]

Re: GPS enhanced cruise control?

why not just add the speaking software, so you can say to the car. hill coming..

Kind of like a car version of "Bitchin Betty" for aircraft? Need to have a cool sexy accent

[Barry Donovan]

Re: GPS enhanced cruise control?

electronics suck..and for those in this thread that fell for it..the babble all the way to outer space and back to gain a goddamn cruise control proves the insanity.

how bout an altimeter with no reading, just to sense that is a grade...and for some reason, my 78 delta88 gave more throttle on a hill, carbed, cruise control..no computer gadget anywhere.... what was it riding, to know to accelerate?

with downdraft timing to boot, this lag crap is a reverse psychology from electronics flunkees...ignore them.

[BBR]

Re: GPS enhanced cruise control?

Dude, 99% of the time I don't know what the hell you are talking about and 85% of the time I don't think you know what the hell you are talking about. You last post certainly falls under both those categories.

:

[TOPDOWN]

Re: GPS enhanced cruise control?

I am new but wanted to join in the fun! I heard about this too and thought it would be a good idea, i am generally opposed to too much tehno in cars though, too much to look at too much to pay attention to. gets in the way of just driving and most drivers can figure out when there is a hill and adjust their pedal pressure.... My dad liked gadgets though so...

[CTX-SLPR]

Re: GPS enhanced cruise control?

I know someone at some point (Mercedes or BMW I think) had accellerometers and tiltmeters to actively determine if the need for increased or decreased throttle was because of an elevation change to know how to react.

What about using the cruise control radar for detecting uphills though it wouldn't do much for downhills.