JohnOver
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LEAF needs new cruise control algorithm - Like Volvo trucks

Tue Jul 31, 2012 9:33 am

I think that most of us don't use the LEAF's cruise control because if you are traveling over any kind of hills, you can do better by dropping speed on the climb and picking up speed on the descent. As we all know (or should know) it's better to not have used energy from the battery, than to have to put some back. The round-trip efficiency in/out of the battery is much debated here on the MNL forum, but realistically is probably no better than 50%.

Volvo trucks now have an intelligent cruise control system, called "I-See" that does not try to hold one speed. It operates like we do, speeding up on the downhill and slowing down on the uphill. This system is touted as improving fuel efficiency by 5% without recovering any of the vehicles kinetic energy.

Here's a link to an article on the system: http://www.nelsonpub.com/cms/dfx/opens/ ... icle&pn=04.
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TonyWilliams
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Re: LEAF needs new cruise control algorithm - Like Volvo tru

Tue Jul 31, 2012 9:56 am

JohnOver wrote: Volvo trucks now have an intelligent cruise control system, called "I-See" that does not try to hold one speed. It operates like we do, speeding up on the downhill and slowing down on the uphill. This system is touted as improving fuel efficiency by 5% without recovering any of the vehicles kinetic energy.
Douglas Aircraft had something like that on planes delivered to Alaska Airlines. It would allow the plane to go up and down 250 feet with the wind currents, as opposed to constantly working the auto-throttles to stay perfectly level and on speed.

palmermd
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Re: LEAF needs new cruise control algorithm - Like Volvo tru

Tue Jul 31, 2012 10:07 am

Cruise control could set a fixed power level rather than a fixed speed. This would work as you described, but if I were implementing it I would go a step further and put a maximum and minimum speed as well. So say you set it to 12kW and that keeps you at 58mph on level ground. I'd put in 65mph max and 50mph minimum so that if you fell to the minimum it would apply more power to maintain a minimum speed and then if you were going downhill faster than maximum it would reduce power to not exceed the max.
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derkraut
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Re: LEAF needs new cruise control algorithm - Like Volvo tru

Tue Jul 31, 2012 10:15 am

I use cruise control all the time when driving the Freeways, to hold a constant speed. Changing speeds up & down hills on the freeway would be BIG trouble, and would produce many "bird" salutes around here. :roll:
Derkraut
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Stanton
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Re: LEAF needs new cruise control algorithm - Like Volvo tru

Tue Jul 31, 2012 10:51 am

JohnOver wrote:I think that most of us don't use the LEAF's cruise control because if you are traveling over any kind of hills, you can do better by dropping speed on the climb and picking up speed on the descent.
Speak for yourself! I use cruise control EVERY time I'm on the highway and think it works fine as designed. As long as you keep a reasonable speed (I keep it under 60), it seems to be very efficient as well.
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TonyWilliams
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Re: LEAF needs new cruise control algorithm - Like Volvo tru

Tue Jul 31, 2012 11:05 am

Stanton wrote:
JohnOver wrote:I think that most of us don't use the LEAF's cruise control because if you are traveling over any kind of hills, you can do better by dropping speed on the climb and picking up speed on the descent.
Speak for yourself! I use cruise control EVERY time I'm on the highway and think it works fine as designed. As long as you keep a reasonable speed (I keep it under 60), it seems to be very efficient as well.
Guys, he's not suggesting that the cruise control doesn't work fine. What he is doing is exploring an automated way to increase efficiency up and down hills. It doesn't have to have a wide speed delta; it might only be 5 or 10 miles an hour.

mynameisjim
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Leaf Number: 23226
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Re: LEAF needs new cruise control algorithm - Like Volvo tru

Tue Jul 31, 2012 11:31 am

TonyWilliams wrote:
JohnOver wrote: Volvo trucks now have an intelligent cruise control system, called "I-See" that does not try to hold one speed. It operates like we do, speeding up on the downhill and slowing down on the uphill. This system is touted as improving fuel efficiency by 5% without recovering any of the vehicles kinetic energy.
Douglas Aircraft had something like that on planes delivered to Alaska Airlines. It would allow the plane to go up and down 250 feet with the wind currents, as opposed to constantly working the auto-throttles to stay perfectly level and on speed.
Airbus does that, too. It has a buffer of altitude and airspeed before it adjusts the throttles in cruise. Our car should be able to keep up with a 24 year old airplane.

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ebill3
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Re: LEAF needs new cruise control algorithm - Like Volvo tru

Tue Jul 31, 2012 11:36 am

derkraut wrote:I use cruise control all the time when driving the Freeways, to hold a constant speed. Changing speeds up & down hills on the freeway would be BIG trouble, and would produce many "bird" salutes around here. :roll:
+1

Yes Sir. Gotta love those big trucks crawling up hills and zooming down the other side. :o
All electric - red LEAF, green Tesla S. No ICE.

jkirkebo
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Re: LEAF needs new cruise control algorithm - Like Volvo tru

Tue Jul 31, 2012 12:36 pm

JohnOver wrote:I think that most of us don't use the LEAF's cruise control because if you are traveling over any kind of hills, you can do better by dropping speed on the climb and picking up speed on the descent. As we all know (or should know) it's better to not have used energy from the battery, than to have to put some back. The round-trip efficiency in/out of the battery is much debated here on the MNL forum, but realistically is probably no better than 50%.

Volvo trucks now have an intelligent cruise control system, called "I-See" that does not try to hold one speed. It operates like we do, speeding up on the downhill and slowing down on the uphill. This system is touted as improving fuel efficiency by 5% without recovering any of the vehicles kinetic energy.
Thanks, but no thanks. I use the cruise control all the time (probably >80% of miles driven are with CC on) and it works perfectly the way it is with one exception: It doesn't use the full regen available so I have to ride the brake pedal on steep downhills to get enough regen. This of course cancels CC completely. So please make the full regen available to CC regardless of driving mode.

Slowing down and speeding up defeats the purpose of CC, drive manually if you want to do that. Just don't do it with cars behind you please, few things are more annoying than people who slow down uphill and in turns and then speed up again when you have an opportunity to pass them...

If you want to save energy, just keep a (steady) lower speed where you can without hindering anyone. 10 mph slower makes a HUGE difference.

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TomT
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Re: LEAF needs new cruise control algorithm - Like Volvo tru

Tue Jul 31, 2012 12:41 pm

+1 I use cruise most-all the time. The argument could also be made that free-wheeling down a hill at 70 is no more efficient than regen at 60 due to increased drag...
derkraut wrote:I use cruise control all the time when driving the Freeways, to hold a constant speed. Changing speeds up & down hills on the freeway would be BIG trouble, and would produce many "bird" salutes around here. :roll:
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