Now using "D", not "eco" for safety

[Nubo]

Of course it is real, what I'm asking is why have it? It is emulation in that letting up on the throttle of an ICE car gives engine braking as a mechanical consequence unless the driver shifts to neutral. But for an EV, it's merely a design decision not a consequence. So why do it?

To recapture energy!

Why can't the regen be blended into the brakes in such a way that friction brakes do not apply until regen is already maximized?

It does do this to some extent. But you also have to take into account that on a full pack , there is no regen available. So if you did what you are proposing, the change in pedal feel from when the pack is full to when it isn't would be quite drastic. As it is now, on a full pack, that first stop can be a bit unnerving..

Why is that an unvavoidable consequence? If the controller were smart enough to blend regen and friction, why should it matter if regen is available? Again, my premise was simple -- engage regen until maximized then apply friction as needed. If I command a certain deceleration rate, and there is no regen available, the friction would be engaged as appropriate. Or, the converse -- if regen is available retard the hydraulics. Thus the hydraulics would always be ready for controller failure, etc..

Seems like a fairly straightforward relationship between pedal position, speed of pedal application, vehicle acceleration, regen, and hydraulics. From what you describe, the blending is not being done at this sophisticated a level. But I don't understand why it could not be. The elements seem to be in place, just not being employed that way.

 

[derkraut]

I read this entire thread regarding "D" vs "ECO", and I have come to the conclusion that------------(are you ready??)

I feel strongly both ways. :mrgreen: :mrgreen: :mrgreen: :mrgreen: :mrgreen:

 

[turbo2ltr]

Why is that an unvavoidable consequence? If the controller were smart enough to blend regen and friction, why should it matter if regen is available? Again, my premise was simple -- engage regen until maximized then apply friction as needed. If I command a certain deceleration rate, and there is no regen available, the friction would be engaged as appropriate. Or, the converse -- if regen is available retard the hydraulics. Thus the hydraulics would always be ready for controller failure, etc..

Seems like a fairly straightforward relationship between pedal position, speed of pedal application, vehicle acceleration, regen, and hydraulics. From what you describe, the blending is not being done at this sophisticated a level. But I don't understand why it could not be. The elements seem to be in place, just not being employed that way.

Anything can be done...with enough money. To do what you are talking about, you'd need a brake by wire system...which is more complex, more expensive, and probably more prone to failure than the tried and true hydraulic system. Can it be done? Absolutely. But is the gain worth the cost?

 

[tps]

Why is that an unvavoidable consequence? If the controller were smart enough to blend regen and friction, why should it matter if regen is available? Again, my premise was simple -- engage regen until maximized then apply friction as needed. If I command a certain deceleration rate, and there is no regen available, the friction would be engaged as appropriate. Or, the converse -- if regen is available retard the hydraulics. Thus the hydraulics would always be ready for controller failure, etc..

Seems like a fairly straightforward relationship between pedal position, speed of pedal application, vehicle acceleration, regen, and hydraulics. From what you describe, the blending is not being done at this sophisticated a level. But I don't understand why it could not be. The elements seem to be in place, just not being employed that way.

Anything can be done...with enough money. To do what you are talking about, you'd need a brake by wire system...which is more complex, more expensive, and probably more prone to failure than the tried and true hydraulic system. Can it be done? Absolutely. But is the gain worth the cost?

I'm guessing that Nissan wanted to avoid a full brake-by-wire system to avoid the added cost of the redundancy which would be required to ensure the important braking function does not fail. The way they implemented it, I'm guessing that if you really stomp on the brake pedal the car's conventional hydraulic brakes will engage, even if the electronic systems which control the auxilliary regenerative braking have an arbitrary fault. Any type of true drive-by-wire systems require a much higher level of redundancy than the LEAF provides to approach the level of safety required in an automotive application.

BTW -- In my (admitedly short) 275 mile, 2 day experience with the Hertz rental LEAF, I found I much prefered "D" to "ECO" since it allowed me to "almost coast" with my foot in front of the brake pedal. This way I felt comfortable coasting as I was following the car ahead, ready to depress the brake pedal to get maximum regen and then quickly apply the hydraulic brakes if necessary as the car ahead came to a stop at a light, stop sign, etc.

 

[EVDRIVER]

Why is that an unvavoidable consequence? If the controller were smart enough to blend regen and friction, why should it matter if regen is available? Again, my premise was simple -- engage regen until maximized then apply friction as needed. If I command a certain deceleration rate, and there is no regen available, the friction would be engaged as appropriate. Or, the converse -- if regen is available retard the hydraulics. Thus the hydraulics would always be ready for controller failure, etc..

Seems like a fairly straightforward relationship between pedal position, speed of pedal application, vehicle acceleration, regen, and hydraulics. From what you describe, the blending is not being done at this sophisticated a level. But I don't understand why it could not be. The elements seem to be in place, just not being employed that way.

Anything can be done...with enough money. To do what you are talking about, you'd need a brake by wire system...which is more complex, more expensive, and probably more prone to failure than the tried and true hydraulic system. Can it be done? Absolutely. But is the gain worth the cost?

The regen is very mild and set that way not to scare people. The car was dumbed down so it seemed exactly like a boring American car with low regen and over-boosted steering for people that have no clue how a real car should feel. The brake system is fully capable of blending more regen. I have driven many EVs with even 5X the regen of the LEAF and the same curb weight and there is no issue and they don't have the fancy electronic braking. The car was made to be like a normal average car and I think they surpassed that goal. If you drive the car in a straight line it feels great, after that it is a poor performer. They made the suspension The suspension is made for comfort, too bouncy and scary at times. Even Nissan admits publicly that the car was designed to be this way. It's perfect for the Japanese Market. If Ford sells an EV I expect it to feel and drive far better and have much better functionality overall.

 

[teamveevee]

Experts, Changing the modes ECO -> D, D->ECO while cruising at ~60 miles/per hour, does it have any impact on the car/transmission in the long run?. I normally try to keep it in the same mode that i started from the beginning till end, instead of changing it during the trip based on road/traffic conditions.

 

[davewill]

Experts, Changing the modes ECO -> D, D->ECO while cruising at ~60 miles/per hour, does it have any impact on the car/transmission in the long run?. I normally try to keep it in the same mode that i started from the beginning till end, instead of changing it during the trip based on road/traffic conditions.

Nope. There's no transmission, and therefore no gear changing between "D" and "ECO". It's strictly a computer thing. The only issue to be aware of is that if you shift while pushing the accelerator, the car's acceleration will change abruptly to match the new mode. In particular when shifting to "D", this can cause the car to surge forward.

 

[tps]

changing between "D" and "ECO". It's strictly a computer thing

Even shifting to reverse is a computer thing; it runs the motor backwards. Now try that with an ICE!

 

[TonyWilliams]

changing between "D" and "ECO". It's strictly a computer thing

Even shifting to reverse is a computer thing; it runs the motor backwards. Now try that with an ICE!

Unless the car is moving forward at greater than 7mph; then it just goes to neutral.

 

[SnaxMuppet]

Something I have found is that when pressing the brake pedal the regen starts to come in, then as I press more the regen increases, but if I press the brake pedal even further the regen comes off completely and the pads take over 100%.

I was surprised at this. I would have thought that it would be clever enough to be able to blend together full regen braking alongside the pads to give me the desired stopping power. It seems not. It seems that either you are regen braking OR using the pads.

As for Tesla putting on the brake lights when heavy regen braking... the Tesla regen is much stronger than the Leaf's. It is very much like firmly pressing the brakes and so for the Tesla it is more appropriate. I would like to have seen more regen on the Leaf. I would also like to have seen no regen at all with feet off. Or even better... have the amount of regen adjustable... this must be easy as it is probably just a setting on the computer (?).

 

[suresnoi]

Something I have found is that when pressing the brake pedal the regen starts to come in, then as I press more the regen increases, but if I press the brake pedal even further the regen comes off completely and the pads take over 100%.

I was surprised at this. I would have thought that it would be clever enough to be able to blend together full regen braking alongside the pads to give me the desired stopping power. It seems not. It seems that either you are regen braking OR using the pads.

Can anyone confirm this ? It would be surprising. A Prius will maintain 100% regen while the disk brakes take the excess of braking required. So :?:

 

[SnaxMuppet]

Well, I tried it several times yesterday to show my wife because I was surprised.

I used the power gauge on the centre console to confirm that regen had in fact returned to near zero when I pressed harder on the brake pedal.

If someone else could confirm this that would be great... I will try it again later today if I go out.

 

[JimSouCal]

I used the power gauge on the centre console to confirm that regen had in fact returned to near zero when I pressed harder on the brake pedal.

How hard does one need to press on the brake pedal for this to happen. Enough to engage the ABS? I tried tonight at the end of a steep grade, and it seems that the regen bubbles stayed lit, but I didn't really want to press any harder as there was traffic behind me.

For what it is worth, I seem to be getting pretty much the same economy in D as in ECO. Since at times I need to drive another car with a very sensitive accelerator pedal, I am sticking with using D and a relatively tame push of my foot most of the time...

 

[LEAFfan]

Unless the car is moving forward at greater than 7mph; then it just goes to neutral.

So what happens at 6 or 7 mph when you throw it into reverse? Has anyone tried it? The OP that told us about this a long time ago must have tried it because how else would they know the magic number is '8'?

 

[LEAFfan]

If someone else could confirm this that would be great... I will try it again later today if I go out.

Same here!

 

[TonyWilliams]

Unless the car is moving forward at greater than 7mph; then it just goes to neutral.

So what happens at 6 or 7 mph when you throw it into reverse? Has anyone tried it?

Apparently, yes, it has been tried. The car does, in fact, go to reverse.

I don't intend to test that particular "feature", at least not on my purchased car!

 

[TonyWilliams]

For what it is worth, I seem to be getting pretty much the same economy in D as in ECO. Since at times I need to drive another car with a very sensitive accelerator pedal, I am sticking with using D and a relatively tame push of my foot most of the time...

I'm reposting this from an earlier, well thought out, post on the subject:

ECO mode does three things:
1) Lowers the accel-pedal's gain.
2) Increases accel-pedal lift regen.
3) Changes the A/C compressor logic to permit greater temp spreads thereby improving efficiency.

Depending upon how you drive, ECO can be a big improvement in efficiency (like 10%) or none at all. Coasting is more efficient than regen because regen is not 100% efficient.

 

[LEAFfan]

+1! There's no way anyone can do better in 'D' than ECO. If they think they can, I'll challenge them. :mrgreen:

 

[TonyWilliams]

+1! There's no way anyone can do better in 'D' than ECO. If they think they can, I'll challenge them. :mrgreen:

Ok, here's the challenge. We both drive 60mph down the same street for 10 miles. Both with the A/C off.

You use ECO and I use D. Who will win ?

 

[LEAFfan]

+1! There's no way anyone can do better in 'D' than ECO. If they think they can, I'll challenge them. :mrgreen:

Ok, here's the challenge. We both drive 60mph down the same street for 10 miles. Both with the A/C off.
You use ECO and I use D. Who will win ?

LOL, that's hwy speed. I'm talking about surface street speeds with top speed 45. Did the OP say his commute was at hwy speeds the whole time? If so, then the only way I would win is if we both used A/C.