Altimeter In Automobile GPS?

The elevation data could be added to the map data base, then when you plot a route, the car could do some predictive battery management, etc.

 

I'm thinking that the Mk-1, Mod-0 eyeball would still trump the GPS/GIS/semi-intelligent adaptive cruise control for the purposes of fuel efficiency.

Sorry......not trying to pee in anybody's Wheaties. Helluva good idea though.

 

A few years ago I heard of some heavy truck cruise control doing this for improved fuel efficiency.

 

If the Prius computer uses a barometer in conjunction with throttle demand to deliver the most efficient fuel mixture, it's already using an "altimeter". As elevation increases the CCs of fuel have to be decreased in ratio with the decreased density of oxygen. Unless the ICE is supercharged - but I don't think it is.

 

If you're referring to the idea of speeding up on the downhills and slowing on the uphills, this behavior, while improving fuel efficiency, is generally considered to be a poor driving habit, as other drivers cannot anticipate your behavior. It results in either driving over the speed limit at the bottoms, or driving well slower than the flow of traffic at the tops.

OTOH, the Prius, and especially the PiP with its larger battery, could theoretically use such information to improve battery usage, building up charge when it will shortly be needed for uphills, and depleting battery SoC when a long downhill is about to provide a big regen opportunity.

 

All modern cars -- at least those sold in large enough quantities to need to meet EPA emissions requirements -- do this already.

 

^^ understood, but I believe the GPS mapping database would do better as it can look up known elevations on the current road, rather than try to predict elevations ahead based on current trend.

I was thinking only in terms of cruise control, with built-in slope-aware hypermiling. Were you thinking of ordinary engine fuel management? The closed loop emission control systems do that portion very well already.

 

Most modern cars use Mass Flow Sensors (MAF) to measure airflow in terms of mass rather than volume, so barometric pressure isn't critical.

 

I want to move where Daniel lives. Where erratic driving behavior is considered slowing going up hills and speeding up going down them. I used to drive in Boston commuter traffic. They have a COMPLETELY different definition there.

 

The insanity of large cities is one of several reasons why I've chosen never to live in such places. Though I should say that while I love hiking in the mountains, I've always lived in relatively flat places.

 

There is a patent out for optimized routing based on GPS and topographic data. Someone beat you to the idea.

Tom

 

We have discussed the idea previously, a topographic map which the GPS accesses to optimize the SOC of the battery based upon an upcoming ascent or decent, etc. I have no idea what the gains might or might not be, though.

In areas with numerous roads and thus different route choices, I'd imagine that it would require inputting a route for it to work correctly. Otherwise, it would have no idea which way you planned to go.

 

Yes, it would need to know your proposed route to do any useful planning.

One exmple of how it would benefit fuel economy would be the case where the car is climbing a grade with a downgrade coming up after the downgrade. The car could draw more energy from the battery than it normally would climbing the grade if it knew it was going to get recharged for free on the upcoming downgrade.