Cruise Control fyi

[mwalsh]

So, you should be able to see the cruise control being too aggressive by watching the bubbles, right? Has anyone seen this?

Totally. When the CC is trying to get back up to speed, it's not at all uncommon for the car to run up to +3 bubbles (that I've noticed - possibly even +4 bubbles)

Also, what I'm curious about is: are people seeing the computer estimate range differently upon turning on the CC, or actually getting less range when they use it?

No, not seeing anything different on that front.

Lastly, does the CC behave differently when ECO mode is engaged?

Not so much. The car still feels sluggish though (my pet peeve with ECO acceleration).

 

[Electric4Me]

So, you should be able to see the cruise control being too aggressive by watching the bubbles, right? Has anyone seen this?

Totally. When the CC is trying to get back up to speed, it's not at all uncommon for the car to run up to +3 bubbles (that I've noticed - possibly even +4 bubbles)

I find the same behavior in ICE cars, and usually prefer getting close to my set speed manually before re-engaging the CC.

 

[garygid]

When under CC, touching the brake de-activates CC, right?

Under CC, does CC use Regen effectively when it needs to "slow" the car"?
See the power-usage screen.

 

[sdbonez]

Maybe I'm just out in left field, but you should easily be able to get more mileage on ANY car by not using the cruise control. It's the difference between someone intelligently using the gas pedal (speed dynamic based on conditions) vs. static speed.

Example: You're headed up a little hill at 40mph. It's just a short hill and there's a downgrade on the other side
With cruise: you car downshifts to maintain speed at 40mph
Without cruise: you keep some pressure on the gas but avoid the downshift letting your car drop to 35mph before hitting the peak and then coasting (to 45mph) on the other side

Now cruise definitely works better for someone who's not paying attention, isn't experienced, or just doesn't care - but mileage will improve with intelligent use of the gas pedal in an example like above.

 

[sdbonez]

...of the gas pedal...

oops, I mean, accelerator pedal

 

[planet4ever]

Totally. When the CC is trying to get back up to speed, it's not at all uncommon for the car to run up to +3 bubbles (that I've noticed - possibly even +4 bubbles)

There's a theory about that, which I half believed for a while. Now I'm waiting for proof one way or the other. The theory goes that gasoline engines are very inefficient in hard acceleration, so "flooring it" does waste gas. But, says the theory, electric motors are still efficient when working hard. So, yes, of course an electric motor uses a lot more power when accelerating hard, but if you use that power for a shorter time, have you really used more energy?

Let's think about a relatively low speed case where we don't have to worry about air resistance. If CC is set at 40 and we've had to slow to 30 because of traffic, is it better to get back to speed by running +3 bubbles for 2 seconds or +1 bubble for 6 seconds? I neither know the answer to that question nor do I know whether those numbers are anywhere close to reality. I only know it sounds like an interesting question to ask. It's possible that Nissan engineers have asked that question and concluded that the faster acceleration does not waste energy while giving the driver more satisfaction.

 

[EVDRIVER]

Totally. When the CC is trying to get back up to speed, it's not at all uncommon for the car to run up to +3 bubbles (that I've noticed - possibly even +4 bubbles)

There's a theory about that, which I half believed for a while. Now I'm waiting for proof one way or the other. The theory goes that gasoline engines are very inefficient in hard acceleration, so "flooring it" does waste gas. But, says the theory, electric motors are still efficient when working hard. So, yes, of course an electric motor uses a lot more power when accelerating hard, but if you use that power for a shorter time, have you really used more energy?

Let's think about a relatively low speed case where we don't have to worry about air resistance. If CC is set at 40 and we've had to slow to 30 because of traffic, is it better to get back to speed by running +3 bubbles for 2 seconds or +1 bubble for 6 seconds? I neither know the answer to that question nor do I know whether those numbers are anywhere close to reality. I only know it sounds like an interesting question to ask. It's possible that Nissan engineers have asked that question and concluded that the faster acceleration does not waste energy while giving the driver more satisfaction.

Bottom line- It's worse in an EV (more sensitive). I have easily over 75K of EV miles watching SOC and real-time consumption as well as logged data to recorders. Not silly bubbles, Prius comparisons, guesses, or theories. I have built a modern conversion with a brand new car form the ground up, owned two factory AC EVs that I modified, reconfigured inverters, build custom charge interfaces on multiple Brusa and PFC chargers, built several custom EVSE interfaces, etc, etc, etc. All the poor information about EVs here is getting very frustrating. Most info here (with exceptions) are anywhere form educated guesses to just made up answers. Any one can buy detailed books and study EV theory and learn quite a bit, they are sold on the internet and if one is really interested they can do some reading but the best way is to learn by building, you will really learn about EVs that way Owning a leaf and watching bubbles and driving around does not give much in-depth tech knowledge but it is a good starting point. As time goes on more EV truths will be revealed. Just wait until people start digging into these cars and getting more detailed readings.

 

[Electric4Me]

Totally. When the CC is trying to get back up to speed, it's not at all uncommon for the car to run up to +3 bubbles (that I've noticed - possibly even +4 bubbles)

There's a theory about that, which I half believed for a while. Now I'm waiting for proof one way or the other. The theory goes that gasoline engines are very inefficient in hard acceleration, so "flooring it" does waste gas. But, says the theory, electric motors are still efficient when working hard. So, yes, of course an electric motor uses a lot more power when accelerating hard, but if you use that power for a shorter time, have you really used more energy?

Let's think about a relatively low speed case where we don't have to worry about air resistance. If CC is set at 40 and we've had to slow to 30 because of traffic, is it better to get back to speed by running +3 bubbles for 2 seconds or +1 bubble for 6 seconds? I neither know the answer to that question nor do I know whether those numbers are anywhere close to reality. I only know it sounds like an interesting question to ask. It's possible that Nissan engineers have asked that question and concluded that the faster acceleration does not waste energy while giving the driver more satisfaction.

Well, strictly speaking, regardless of how efficient an electric motor may or may not be when worked hard, in the scenario you layout above it *has* to use less energy in the 6 second case because your average speed is less.

 

[EVDRIVER]

Why do people even use a cruise control on busy freeways in say LA. Seems pointless to me, they were developed for long continuous highway drives where one get's tired from holding the foot in one position.

 

[mwalsh]

Owning a leaf and watching bubbles and driving around does not give much in-depth tech knowledge

Don't mess with my bubbles man....it's all I got! :lol:

 

[Electric4Me]

Why do people even use a cruise control on busy freeways in say LA. Seems pointless to me, they were developed for long continuous highway drives where one get's tired from holding the foot in one position.

I use cruise control all the time as "ticket control"!

 

[TomT]

Theoretically, gasoline engines are most efficient at wide open throttle (due to pumping losses) and diesels are most efficient at idle (due to an excess of combustion air). Everything else being equal, of course...

There's a theory about that, which I half believed for a while. Now I'm waiting for proof one way or the other. The theory goes that gasoline engines are very inefficient in hard acceleration, so "flooring it" does waste gas.

 

[DaveEV]

Technically, gasoline engines are most efficient at wide open throttle (due to pumping losses) and diesels are most efficient at idle (due to an excess of air).

Technically, it's more complicated than just throttle opening, too. But now we're getting OT.

 

[TomT]

Ditto. Particularly on some wide-open 4 lane city stretches where the speed limit is a ridiculous 40mph...

I use cruise control all the time as "ticket control"!

 

[ENIAC]

Here's an LEAF cruise control undocumented (feature?) I found the other day. I enabled the cruise control (shows on your dash) then I was distracted and forgot to push down on the cruise/set switch. After awhile I let off the accelerator expecting the LEAF to drop to 65mph (where had I thought my set point was). Instead, with no set point it began to slow of course. So I thought I must have set the speed much lower in error and I so pressed the accelerate switch up and held it there for maybe 5 seconds. The LEAF never did accelerate, but it did do something (not dangerous at all) which frustrated and embarrassed me even more! Try it and tell me what yours does!

 

[mwalsh]

Did it say "I'm sorry, Dave. I'm afraid I can't do that"?

 

[ENIAC]

Did it say "I'm sorry, Dave. I'm afraid I can't do that"?

:lol: :lol: :lol:
Get your fanny out there and try it!

 

[Ohmie]

Sorry, but I don't believe the guy knows what he is talking about!

I talked with the LEAF salesperson tonight and this is what said. He said that cruise control limits range significantly. I'm sorry I didn't source my info from the start. He volunteered this information. He explained that this problem wasn't due to forcing high speeds up hills (as cruise controls do, wasting energy), it was for some other reason. I.e., the cruise control system itself is a bit of an energy hog.

I have to agree completely, mogur!! Who is this nut?!

Hey wait a minute...!

Indeed, I totally jumped the gun. I've read the manuals, etc. and what information Kolmstead has gathered and what MWalsh has shown through testing does seem correct.

And yet I talked with another person at the dealership today and he re-affirmed this idea that the cruise control feature is, in itself, an energy hog, and is to be avoided for extended range. So there's some misinformation out there.

Thanks for clarifying everyone. "Chomp, chomp" - that's me eating crow. I'd prefer to go with official Nissan literature and real world tests over simple hearsay.

The title of the thread may more appropriately read, "fyi, beware there's cruise control misinformation out there!"

I attempted to test the cruise control on/off over a number of flat miles on my commute today, but traffic wouldn't allow extended tests. But in regards to instantaneous energy economy values, there is no noticeable change between CC on/active (set), CC on/inactive (not set), and CC off. This seems to confirm that the CC serves to economize fuel in the same way as in an ICE.

I'm still learning... this is a complicated vehicle. I appreciate the discussion, thanks especially to mwalsh and kolmstead. Sorry for misleading folks, this wasn't my intention! Cheers.

 

[mwalsh]

I'm still learning... this is a complicated vehicle. I appreciate the discussion, thanks especially to mwalsh and kolmstead. Sorry for misleading folks, this wasn't my intention! Cheers.

LOL! We are all learning as we go. Me, I've learned that my suppositions about what SOC percentages are encompassed by the bars on the dash and in the OP are incorrect. Any of that crow left? :lol:

 

[DaveinOlyWA]

to CC or not to CC; THAT is the question!!

if driving on a PERFECTLY flat road, with no traffic, no lights, no stops. then CC is fine. the less you vary speed, the more efficiently you will drive...

*yawn*
rubs sleep out of eyes

ok, now that the dream is over, lets talk reality.

what the Nissan guy said is somewhat true but using CC does not have any kind of "overhead" penalty. but it is the most inefficient way to drive unless you are in the dream sequence detailed above.

now the question of accelerating quickly for short duration to regain set speed or slowly over a longer period of time question.

on paper it would not seem to matter, except that the car has weight ergo momentum. so the faster you accelerate, the more power you will use. keep in mind that regaining a set speed slowly might be a good thing in heavy traffic as this prevents you from having to slow down as much since as we know, the slower you go, the less you have to slow for traffic.

the Leaf has various types of forces it employs to get you down the road.

battery
regen
momentum or constant velocity
gravity

now driving efficiently means manipulating the above. there is no real set answer as to how best to maximize efficiency other than leave the first one alone as much as possible. then pretend the 2nd one does not exist. (back to that dream!!) or iow, use it as little as possible.

which brings us to the last 2. momentum is the hard earned status as a result of the battery. maintaining momentum takes less than ¼ of the power that it takes to get there (actual power varies by speed due to air resistance, etc) . so its more than 4 times the power to accelerate. regen gets back less than 10% of that power...even the math challenged will figure out the "rule" on that.

so maintaining a constant speed without regen is a good thing but now we come to the last one which should be first on the list because that is what we want to use the most; gravity.

now, we have a contradiction and the reason why there is no one fast rule to efficiency. using CC and gravity means we will regen going downhill if its steep enough. we dont want that, so our speed must be changed so the constant velocity rule is not always the best way to go, but once again, there is no "best" way. it all depends on where you are, where you are going and a million other things.

but the key thing to remember is that if you are doing it wrong, carwings will tell you.

all i can say is "learn your car". ask it, it will tell you everything you need to know