Smart cruise control

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Smart cruise control

Electric Vehicle Discussion List mailing list
Is there such a thing as a smart cruise control?  That is a cruise control that will adjust to terrain and draw no more than a set amount of energy.  So pick a starting speed on level ground it will keep that speed until a slight grade and then slow to a predecided speed and then keep that speed.  It will then speed up when terrain permits.  Sure you could wedge you foot but I have found that by playing the pedal I can keep up my speed and lessen my energy use.  Sort of playing the ups and downs.  Lawrence Rhodes
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Re: Smart cruise control

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I think a smart cruise control would be nice but I have not seen it yet.  If there was a system that would allow you to say gain 15 to 20 kph (mph?) on down slopes and then not engage again until you dropped to say minus 5 kph on the upslope that might emulate what drivers do when they hyper-mile.

I do wonder about your statement that using cruise control is always less efficient.  On my smart car it will not toggle between using power and generating power if the grade is such that it can coast.  There is no mode where regen is actually using power, it may not be much but regen always adds electrons back to the battery.  In hilly terrain where you can coast over the speed limit down and use the momentum to climb back that would preclude using the cruise control but that seems to be a driver decision and not a ‘cost’ of using it.

Lawrence

> On Feb 27, 2017, at 12:51, Lawrence Rhodes via EV <[hidden email]> wrote:
>
> Is there such a thing as a smart cruise control?  That is a cruise control that will adjust to terrain and draw no more than a set amount of energy.  So pick a starting speed on level ground it will keep that speed until a slight grade and then slow to a predecided speed and then keep that speed.  It will then speed up when terrain permits.  Sure you could wedge you foot but I have found that by playing the pedal I can keep up my speed and lessen my energy use.  Sort of playing the ups and downs.  Lawrence Rhodes
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Re: Smart cruise control

tomw
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In reply to this post by Electric Vehicle Discussion List mailing list
Actually, I think that would be a dumb cruise control because it would vary vehicle speed widely in order to maintain energy/mile in a pre-selected range, resulting in the scenario that Lee described and angering other drivers. It may work fine on almost level ground, but be a real pita to other drivers on widely varying grades.  I can see the semi trying to maintain speed up a hill riding your a** and cursing.  You may think that you wouldn't set the energy/mile low enough for that to happen but how do you know what to set the min/max limits at for a given trip, especially on an unfamiliar route? I think you would end up frequently re-adjusting the limits.  

But humans accomplish this easily.  Just depress the throttle enough to maintain the speed limit, or around x mph below on up hill grades, and coast down hill (around zero battery current) until vehicle speed increases to y mph above the speed limit and gently ease up on the throttle to apply enough regen to slow down about 5 mph, coast again, repeat. The variables x and y are usually about 5 and 8 mph for me. My car has more than enough regen to slow as needed, including when I come up behind a vehicle going much slower downhill and cannot pass (the driver would have to intercede in this case with a min/max energy/mile system).

A cruise control could of course be designed to accomplish the above driving pattern, but it would control based on min/max speed rather than energy/mile, and it would also have to be reset every time the speed limit changes.  That's pretty much how current cruise control works except it attempts to maintain one speed.  I think there are important priorities in addition to maximizing energy efficiency, such as safety and maintaining steady, optimized traffic flow at or close to the posted speed limits.
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w/ an up/downhill min/max speed: Smart cruise control

brucedp5


Way too many years ago (1990's), I poured money into upgrades for the S-10 Blazer conversion EV I had (see
https://brucedp.neocities.org/blazer/
). The now retired San Mateo converter installed a small simple circuit that helped maintain a constant battery current draw. I was lucky to get one as this was how he won EAA distance rally races.

It basically was a dash mounted: flip switch, push button which engaged a relay that then used a knob'd potentiometer as the control to the controller (the relay took the foot accelerator out of the loop/circuit).

Routinely checking my dash cluster mounted link-10 e-meter (looked like:
https://sc02.alicdn.com/kf/HTB13HUeKFXXXXX4apXXq6xXFXXXe/Xantrex-Link-10-formerly-E-Meter-.jpg

http://www.solarray.com/Images/ImagesEVs/Meter.JPG

-now sold as:
http://www.xantrex.com/power-products/power-accessories/linkpro-battery-monitor.aspx
), I could see the battery current held steady on the flat, would naturally slow down & draw more battery current on the uphill (e-motor under more load), and would speed-up & draw less battery current on the down hill (e-motor under less load).

In a effect, it was the same effort a human makes to keep their foot on the accelerator steady as a rock (without the human repeatedly re-adjusting the accelerator position, which wastes power).

Like an ice cruise control, it had the nice effect of letting my foot take a break from having to depress the accelerator on long trips (one less thing to do as part of the constant vigil while driving). BTW, there were micro switches on the brake and clutch levers, that would disengage the circuit, putting the accelerator potentiometer back in control of the controller if there was a panic change, etc..

But as Tom inferred, that up/downhill change in speed would be a pain(pita) for the drivers behind you (ticking them off to do something dumb, etc.). However, in fact my multiple experiences using this nifty circuit was when I drove 160 miles from Silicon Valley to Sacramento (to hang out with the Nedra.com e-racer folk by charging multiple times off the public 6kW Avcon EVSE), by staying the right lane, I minimized that pita effect.

The right-lane racing fools that thought tailgating would make me speed up, were educated after reading the ELECTRIC signage and hov/car pool lane stickers on the rear of my EV, and just passed on the left into the faster lanes. For most drivers behind me, it wasn't as bad as I had feared (and CA drivers can be a real obnoxious bunch).

Having said what I really experienced, I agree with Tom, that it would have been sweeter to have a way to maintain speed on the uphill, and use regen on the downhill (my Blazer did not have regen like today's AC motor controllers do).

So, how does one put more energy into the climb, or less energy on the downhill without varying the current draw on the pack?

The only solution I envisioned was more complex and expensive:
-a buffer pack (perhaps either a prius NiMH, or a small amount of ultracaps) to draw from and capture the regen when either climbing or on the down hill. That smart cruise control would truly have to be smart to:
sense the EV's speed, demands on the e-motor, the battery current draw, and control the power going in and out of the aforementioned buffer pack.

It makes you wonder what we (drivers) will do to maximize range.




For EVLN EV-newswire posts use:
http://evdl.org/evln/


{brucedp.neocities.org}
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Re: Smart cruise control

Electric Vehicle Discussion List mailing list
In reply to this post by Electric Vehicle Discussion List mailing list
Are you TRYING to get almost every driver on the road to hate you and create a road hazard for everyone else?
 
 Jim
 
 
 
 -------- Original Message --------
> From: "Lawrence Harris via EV" <[hidden email]>
> Sent: Monday, February 27, 2017 1:53 PM
> To: "Lawrence Rhodes" <[hidden email]>, "Electric Vehicle Discussion List" <[hidden email]>
> Cc: "[hidden email]" <[hidden email]>
> Subject: Re: [EVDL] Smart cruise control
>
> I think a smart cruise control would be nice but I have not seen it yet. If there was a system that would allow you to say gain 15 to 20 kph (mph?) on down slopes and then not engage again until you dropped to say minus 5 kph on the upslope that might emulate what drivers do when they hyper-mile. I do wonder about your statement that using cruise control is always less efficient. On my smart car it will not toggle between using power and generating power if the grade is such that it can coast. There is no mode where regen is actually using power, it may not be much but regen always adds electrons back to the battery. In hilly terrain where you can coast over the speed limit down and use the momentum to climb back that would preclude using the cruise control but that seems to be a driver decision and not a 'cost' of using it. Lawrence > On Feb 27, 2017, at 12:51, Lawrence Rhodes via EV <[hidden email]> wrote: > > Is there such a thing as a smart cruise control? That is a
 cruise control that will adjust to terrain and draw no more than a set amount of energy. So pick a starting speed on level ground it will keep that speed until a slight grade and then slow to a predecided speed and then keep that speed. It will then speed up when terrain permits. Sure you could wedge you foot but I have found that by playing the pedal I can keep up my speed and lessen my energy use. Sort of playing the ups and downs. Lawrence Rhodes > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20170227/fbe2cffb/attachment.htm> > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Read EVAngel's EV News at http://evdl.org/evln/ > Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA) > _______________________________________________ UNSUBSCRIBE: http://ww
 w.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)


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Re: Smart cruise control

Electric Vehicle Discussion List mailing list
On 28 Feb 2017 at 11:13, Jim Walls via EV wrote:

> Are you TRYING to get almost every driver on the road to hate you and create a
> road hazard for everyone else?

Not everywhere in the world or nation are drivers as impatient and stressed
as they are in California.  People are actually somewhat patient in other
places.  Hard to imagine, I know.  :-\

Look, the speed limit is not a minimum.  In most places, if you need or want
to drive below the limit, there's no good reason not to.  

This "road hazard" business is just plain wrong-headed.  By that standard,
you'd have to ban heavy trucks and farm machinery from the roads.  

You'd also have to kick a lot of older drivers off.  With their diminished
reaction time, such folks have to drive more slowly, in order to drive
safely.

Whether you're driving a gravel truck, hypermiling your ICEV, maximizing
your EV's range, or just aren't in a hurry, IMO a speed within 10% of the
limit -- even 20% -- is entirely reasonable.  

If that's not how it is where you live, maybe you should consider moving  
out here to the Midwest, where people generally aren't so full of righteous
rage all the time.  Of course you'll have to deal with the fact that there
aren't as many public EVSEs here -- and not that many EVs, either.

David Roden - Akron, Ohio, USA
EVDL Administrator

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