Brake Regen Threshold Display?

[plus 3 golfer]

Valkraider I'm glad you get it..  Wish list stuff.  Press brake too hard spinny wheel turns red.  Wasting kinetic energy. Dog runs in front or car pulls out, who cares slam that petal down.  Not everyone has 20 year old sensation in their feet.

So what is your brake score????  

 

I can't beat ptjones, but ours is 95%.  So, removing the "dogs run out in front of you stuff" and not impeding traffic and so forth, I'll bet my wife and I would be close to 99%.  So, I really doubt a red spinning wheel could add much value for most people.

 

Let see how much value one might add with improving ones brake score.  I've got 178 miles in regen miles out of 2300 miles total.  So, let's assume 100% of the regen miles is recovered via braking and none by coasting (very optimistic assumption).  Lets also assume that I could improve my brake score from 95% to 100% (also very optimistic assumption).  Lastly, let's assume that the brake score represents the energy that is recovered (in miles) and is linear.  So, currently I'm 5% short of the 100%.  So, the maximum regen miles that I can recover would be (178/.95-178)= about 9.37 miles over 2300 miles.  So, after 100 k miles, the best I can do is recover an additional 9.37*100,000/2300 = 391 miles. At 40 mpg and $5 gas that's less than $50 in value over 100 k miles and likely a lot less than that.  Hardly worth the discussion.

 

So, even forgetting about it being a potential distraction while braking, there is virtually no value especially if one is realistic vs optimistic in the calculation. :)

[valkraider]

My lifetime score is 96%.

 

Regen numbers and your calculations don't work for me at all. I drive in mountains. A frequent trip of ours has over three miles of regen down as much as a 6% grade - without ever stopping and calculating a braking score. That's one trip we make 10 times a week usually, if not more. Another one I can leave our home and drive for about three miles almost exclusively downhill - a lot with brake regen and a lot with coasting teeny regen, maybe at most 4 stops in there.

 

So my brake score won't mesh accurately with my regen miles counted.

 

But it's not about anything other than I paid $30k+ for the car and I think it would be a neat animation and data point to know when it is pure regen and when it is eating brake pads. Because I am a nerd and I would like to see it.

 

EV+ at gives owners maybe another 1/2 mile of EV miles a day - in an average car driven 12000 miles a year that's like a fraction of a percent. But Ford still developed it and markets it because its cool. This feature is no different.

 

There are tons if features in a car that are if limited value but are still there. Should I start listing out all the features I don't care about? Or should we recognize that my preferences are not your preferences and I think turning the wheel red would be cool.

 

I would rather look at info about what the car is doing than a bunch of leaves.

 

Also - since I do drive on so many long steep hills, I can save a lot of brake pads if I can know when I am in pure regen vs. grinding down disposable parts...

 

My vehicles usually need brakes annually but the C-Max may go years without going through the pads. It saves me hundreds of dollars a year, maybe more.

Edited February 28, 2013 by valkraider

[plus 3 golfer]

I don't want it as an option.  I don't want other to have it as an option. I don't want the car behind me to be potentially distracted by watching a display on the dash while braking instead of what's happening in front of him.  I have no problem using something else to help in regens but not something that requires taking your eyes from the road.  I don't want people believing that such a swirling, changing color display is their ticket to value during normally braking.

 

What I suggested for hills was to have the ability to "shift the downhill energy"  to the generator in stages much like a tiptronic can up/downshift gears.  If you had to slow down more than the generator load allowed, you simply apply the brakes.  This principle could easily apply to normal braking also.  It requires more hardware but the logic is similar to applying the brake pedal position to generator loading except in discrete steps.  The algorithm factors in battery charge and adjusts the mechanical braking accordingly when downshifting.  So, if half way down the hill the battery is full, the brakes are applied to simulate the generator load.

[valkraider]

I don't want it as an option. I don't want other to have it as an option.

You want to make my car payments for me? Because until then I am glad that you don't decide what makes a good option or not...

 

I don't want the car behind me to be potentially distracted by watching a display on the dash while braking instead of what's happening in front of him.

No one does. But I wager you have far bigger things to worry about than me glancing at my gauges. There is all kinds of stuff in cars that people look at. It's not going to change any time soon.

 

By your logic, there should be no readouts at all.

 

I have no problem using something else to help in regens but not something that requires taking your eyes from the road.

So you never look at your gauges then?

 

And why would it "require" it? I am perfectly capable of glancing at a gauge to see what is happening in my vehicle while paying attention to traffic in front of me.

 

A gauge is a gauge. Glancing at a spinning wheel is no different than glancing at a speedometer or a nav screen or a heater setting.

 

MFT has a radio interface seemingly designed by by MC Escher to control 6 inputs, 54 presets, and hundreds of stations. You should worry more about that than the color changing icon.

[plus 3 golfer]

My logic is simple, safety first while braking. It's about adding a feature where the perceived benefit requires taking ones eyes off the road even if momentarily while braking. It's not about looking at gauges at appropriate times. It's not about how you or I drive. Yes, I can glance at gauges while driving. It's about the tailgaters, the weavers and so forth on the road that I don't trust.

 

 

If Ford decides to implement such, I'd use it but I'm not in favor of it. I would prefer paddle shifter like devices on the steering wheel to control generator braking.

 

 

BTW, read the warning about operating the audio / MFT while driving.

 

 

Lastly, why the personal stuff?...

 

 

 

 

[valkraider]

Nothing personal. Just a friendly debate. ;)

 

I could quote an incredibly politically incorrect joke about arguing on the Internet...

 

I respect everyone's opinions, even if they're wrong. ;)

[plus 3 golfer]

Good to hear.  Just some more food for discussion below. :)

 

Have you tried to assess how much energy you capture on these hills?  Does "grade assist" help going down steep grades or will the car still pick up speed?  I haven't driven on any road with long/steep enough grades to really test. According to the manual, it appears that the logic is to keep speed constant going down hill using regen braking.  I would think that means maximum regen braking if warranted.  If I had such a hill I'd take my VCDS and record charge level and other variables and test various strategies to see what might maximize regen charging.  Although with just a Hybrid, there's likely not enough battery storage to make a difference in strategies on a long grade.  My data shows that exiting a freeway on a downhill ramp of about nearly 1/2 mile in length at 70 mph increased the battery charge level by 8% with a 100% brake score in my hybrid.  Since the Energi's battery capacity is over 5 X that of the hybrid there's the potential to capture a lot of energy through regen going down long hills.

 

But on the contrary as an example, there's a 24 mile stretch of US 60 that I travel a few times a year that drops from 5850' to 3450' and climbs back up to 6000' with about 6 miles or so having numerous hairpin curves going up /down the canyon walls of the Salt River and 10+ miles of gradual slope (maybe average 1.5% grade) at the beginning / end of the 24 miles. That's about 3.6% overall grade but with many sections over 6%.   With my TDI I could downshift from 6th to as low as 3rd and not have to use my brakes but for entering many of the hairpin curves (15-20 mph) or for slower traffic.  Speed limit was 65 mph on the gradual down slopes dropping down to 55 on the steeper sections and of course significantly less in the hairpin sections.  My speed on the 65 mph sections could approach 75+ mph had I not downshifted to 5th.  So, I then wonder how much energy can be captured through regen with an Energi over and above "normal use of brakes" including anticipating conditions and use of "grade assist" on such a hill since the characteristics of the hill (including max safe speeds) and flow of traffic would seem to be the primary determinants as opposed to how the driver applies the brakes like when maximizing regen when coming to a complete stop. Of course every hill is different.

 

Secondly, is there enough potential energy in a stretch of highway with a 2400 vertical drop to fully charge an Energi?  No, a 3900 pound car at 2400 feet elevation has a potential energy of about 3.5 kWh.  Take out drag as one converts that potential energy to kinetic energy, inefficiencies of charging and so forth and that number will fall significantly.  So, I'm curious as to what the potential energy one can expect from the hills you travel compared to how much the battery level actually increases. That to me is the $64 question.  

 

Now, let's make an estimate of the energy I recovered in my recorded data above.  The kinetic energy in my hybrid at 70 mph = 0.228 kWh.  My charge level went up about 8% or 1.4 kWh*0.8 = 0.112 kWh.  That's a recovery of slightly less than 50% of the kinetic energy yet my brake score was 100%. IMHO, there's way to much emphasis placed on "brake score".  Yes, it helps FE to get the brake score as high as possible but not as much as most likely believe.   Edit: I forgot to add the PE of my car since the exit ramp was down hill maybe 25'.  That would make the total energy = PE + KE = 0.263 kWh.  So, the recovery is now around 43% = (0.112/0.263).  

 

 

Edited February 28, 2013 by Plus 3 Golfer

[valkraider]

My daily route is in city with traffic. So it's a long slow descent, speed limit is 35. It's hard to tell how much is regained because the "miles" estimate takes into consideration the fact that I am moving without consuming therefore the estimate will be optimistically high, and all I have is a graph display for battery charge. A percent state of charge display would be more useful here.

 

I am going to experiment with spring skiing, I have a very steep downgrade for 12 miles then a reasonably steep downgrade for about 20 miles. The first section has a 20 to 30 mph speed limit and the second section varies from 45 to 55 mph speed limit.

 

In my truck I usually can coast the whole second part. Not the first part - it's too steep and curvy. I am going to start with an empty "Energi" battery (and take a snapshot of the status of the "hybrid" battery when I start) and see how much is regen.

 

I should be able to try L, brakes, and Grade Assist on different days and compare. :)

[darrelld]

I don't want it as an option.  I don't want other to have it as an option. I don't want the car behind me to be potentially distracted by watching a display on the dash while braking instead of what's happening in front of him.  I have no problem using something else to help in regens but not something that requires taking your eyes from the road.  I don't want people believing that such a swirling, changing color display is their ticket to value during normally braking.

 

What I suggested for hills was to have the ability to "shift the downhill energy"  to the generator in stages much like a tiptronic can up/downshift gears.  If you had to slow down more than the generator load allowed, you simply apply the brakes.  This principle could easily apply to normal braking also.  It requires more hardware but the logic is similar to applying the brake pedal position to generator loading except in discrete steps.  The algorithm factors in battery charge and adjusts the mechanical braking accordingly when downshifting.  So, if half way down the hill the battery is full, the brakes are applied to simulate the generator load.

 

VW is implementing the paddle shifter regen control option in the eGolf.

 

http://reviews.cnet.com/8301-13746_7-57403748-48/first-drive-in-the-electric-vw-egolf/

 

Putting it back into drive and coming upon another down slope, Gillies advised me to hit the paddle shifter inscribed with a minus sign. Regeneration drag began to slow the wheels a bit, and a small, empty battery icon appeared on the instrument cluster.

 

Volkswagen installed electric vehicle chargers at its Electronics Research Laboratory.

(Credit: Wayne Cunningham/CNET)

Tapping the paddle shifter again produced more drag and a low level marker in the battery icon. I was able to tap the paddle two more times, bringing the regeneration level to maximum and filling up the battery icon. Likewise, hitting the plus paddle lifted each level of regeneration. It was a fine degree of control to give electric car drivers.

Edited February 28, 2013 by darrelld

[plus 3 golfer]

You know VW gets a lot of things right.  Looks like they took my suggestion. :)  

[ptjones]

I think we need an Heads up display then we wouldn't have to take our eyes off the road. :)

[roninsd]

Re the Grade Assist (tangent): one of the engineers at the Irvine get together mentioned that you could keep the assist on, and it wouldn't activate until you were actually going down a hill.  Keeping it on (usually by accident) would do no damage was his point (not that you should keep it on).

[rcthomas1961]

On my wish list is a simple software update which will display regenerative braking power recovery AS IT IS HAPPENING.  This would reduce the mystery of regenerative braking.  I even worked out the display.  I offer it for your consideration.

 

[Riddley]

I love that Regenerative Braking display suggestion.  Nice work!   :)   That wasn't easy to do. :worship:

[joe]

In a matter relative to applying brake regeneration, does the brake light go on when applying a light enough touch to the brake pedal to activate regeneration but not enough apply the brakes?

 

There are times when I'm going down a slight decline and apply the brake to generate electricity.  I wonder if my brakes lights are one all the way down the hill.

[fotomoto]

It should.  I haven't checked the C-Max but most brake light switches are adjustable.

 

In a matter relative to applying brake regeneration, does the brake light go on when applying a light enough touch to the brake pedal to activate regeneration but not enough apply the brakes? 

[ScubaDadMiami]

The manual says that leaving the CMAX in Neutral does not charge the battery.  Does that mean that gliding in Drive will?  If so, then why doesn't that show up on the Regen?  Or does gliding while in Drive only slightly add a charge while applying the brake lightly will add a much greater charge?

[zhackwyatt]

The manual says that leaving the CMAX in Neutral does not charge the battery.  Does that mean that gliding in Drive will?  If so, then why doesn't that show up on the Regen?  Or does gliding while in Drive only slightly add a charge while applying the brake lightly will add a much greater charge?

If you add the arrows to the battery display (called Charge Assist and Charge Level (or something along those lines I don't have the car in front of me)) then then you will see that when you let your foot off the gas, the battery does charge.  The spinning arrows do not show up.  Those only show up when pressing the brake.  So, applying brakes does add more charge than gliding in Drive. 

[fotomoto]

Depends on what your definition of gliding is.  Many use the term for coasting/no throttle in D which in a hybrid means you're regenerating into the battery but that's not a glide.   Gliding is applying just enough throttle to disengage regen but not enough to really maintain speed or accelerate the car through the EV motor and thus rapidly use up the battery.  Compared to my old Prius, I find it harder to apply or discern if you are in glide mode in the CMax.   I try to get just enough blue on the EV scale to trip the instant mpg scale to max out and no more then the car will begin a very long, slow deceleration without  regen'ing.

[fotomoto]

 The spinning arrows do not show up.  Those only show up when pressing the brake.  So, applying brakes does add more charge than gliding in Drive. 

 

No.  Completely letting off the gas pedal will bring up the circular regen arrows and add a small amount of charge as the car slows.  Light brakings adds even more regen.  Harder braking engages the traditional friction brakes.

 

Correction:  lifting off the gas pedal only brings up the "^" indicator on top of the battery level display signifying it's being charged.

Edited May 17, 2013 by fotomoto

[zhackwyatt]

No.  Completely letting off the gas pedal will bring up the circular regen arrows and add a small amount of charge as the car slows.  Light brakings adds even more regen.  Harder braking engages the traditional friction brakes.

 

Correction:  lifting off the gas pedal only brings up the "^" indicator on top of the battery level display signifying it's being charged.

Isn't that what I said?

[fotomoto]

Isn't that what I said?

LOL, yup, just correcting myself.  I read yours too fast.

[zhackwyatt]

LOL, yup, just correcting myself.  I read yours too fast.

Oh! Cool :salute:

[salsaguy]

Mercedes Benz has a similar commercial for the same kind of computer breaking system. in fact i believe they invented it out were the 1st to have it in their cars.

 

Honda advertises (with an annoyingly stupid ad campaign) their collision avoidance system I think in the new Accord, where the car detects something and helps the people stop, and they look in the back seat at their kid...