Braking best techniques

[ptjones]

Not using brakes gets the best MPG's, but at some point you will need to stop. LOL  I take corners faster (which bugs my wife, my grandson likes it. LOL)so I don't have to use the brakes. After a while you will get use to the seat of your pants feel to tell you if you are braking to hard. :)

 

Paul

[ScubaDadMiami]

No question that braking is not as important as throttle control. However, with just a little additional brake control, you will also certainly get a little better fuel economy, even if it's just a little bit.

[fbov]

Looking at my car's data, my regen miles are about 3-5% of the total mileage, and that at 95% regen. Presumably, you'd have to try very hard to get 50%, and few of us have the test scenario to detect 1.5% change in mileage.

 

So significant? No. But still important for charging and getting the most out of gas invested in hill climbing.

 

Have fun,

Frnak

[ptjones]

I would think you would have higher percentage of Regen miles with higher percentage of City driving. You don't normally use brakes on the FWY.  But you still can have high percentage EV miles even with 80%  HWY miles. My example is 53541mi total, 23371.6 mi. EV, 1439.4mi. Regen, life time MPG 46.2 and BS 98%. Which gives me 44% EV and .027% Regen.  I went back through most of my City Driving IPhone Pics  and found one with a 15% regen score and a few with 10% score so I guess if you only did City driving and were good at hypermiling you could end up with a impressive 10% Regen Score. :shift: 

 

Paul

[plus 3 golfer]

I'm not sure I necessarily buy that a higher regen miles % is associated with city driving.  I would think that regen miles includes ALL regeneration not just using the brakes.  So when one is coasting and using grade assist one is regenerating.  My regen miles is 3.6% with a 94% brake score and my EV miles is 50.7%.  My lifetime mpg is 42.0.

 

We do a lot of freeway driving at 70+ mph and coast coming off ramps up 1/3 to 1/2 mile.  I also try to time lights by coasting and coast to stops.  We also have done many 300-400 mile trips into the mountains where I always use grade assist.  So, why is my FE about 10% lower than Paul's FE even though my EV and regen miles are a higher %?  My guess is that my average speed is considerably higher than Paul's average speed and thus I have significantly more energy available to capture via regeneration when coasting, braking, and using grade assist.

 

One other thought when applying the brakes and that is does the rear friction brakes assist for control purposes when the front wheels are in a pure regeneration mode (no friction braking).  I have read papers that have modeled and IIRC tested various control schemes.  If so, using the brakes for more regenerative braking may be lowering ones overall % regeneration vs coasting to slow down.  One anecdotal fact is that when I feel the surface of the front rotors compared to the rear rotors, the rear rotors have a slightly raised outer lip after 25k miles.  There is no perceived lip on the front rotors. Could this be friction braking wear on the rear?  Maybe others (be good to get someone with little miles on their car) could check their rotors for what appears to be the sign of rotor wear.  

[ptjones]

I thought the Regen Score was for braking only. I thought rear braking only happens when front brakes are working. :)

 

Paul

[plus 3 golfer]

I assume EV energy is all energy supplied by the battery to propel the car and thus would include all sources of energy to charge the battery.  The regen score only applies to when one depresses the foot brake and is used as a tool to help one to not use the friction brakes.  Braking to me simply means that the front wheels have a force applied to them and are slowing down via regeneration and/or friction.  The ABS / stability control algorithms know what is going on and there would be no reason that the rear brakes couldn't be applied anytime.  The ABS can do proportional braking  

 

Wiki says: "When braking or decelerating, the Fusion's hybrid system uses regenerative braking, where the electric drive motor becomes a generator, converting the vehicle's momentum back to electricity for storage in the batteries."   I've always seen discussion on "regenerative braking" to include coasting (decelerating).  Braking does not mean that one has to brake via friction brakes.  So, that's why I assume regen miles is all energy (converted to miles) generated by braking the front wheels.

 

The inverter / battery is capable of 35 kW of sustained charge.  I would think that would then be the maximum braking force that MG2 (traction motor) would apply during regen.  The question then: is 35 kW of braking force to much force to put on the front wheels while the rear end is free wheeling.  I don't know but have a feeling that the rear friction brakes may be used in assisting slow down (the rotors seem to be wearing).  Then, the question is does application of the rear friction brakes affect brake score?

 

Edit: here's the definition of regenerative braking in the owner's manual:

Regenerative Braking System

This feature is used to simulate the engine braking of an internal

combustion engine and assist the standard brake system while recovering

some of the energy of motion and storing it in the battery to improve

fuel economy.

 

 

Edited May 5, 2014 by Plus 3 Golfer

[plus 3 golfer]

Paul, just wondering if your regen miles and EV miles are since you owned the car or from the reset of those values which should have occurred with the 13B07 update.   My dealer SO shows the mileage on my vehicle when the update was performed.  If I inadvertently used the odometer miles to calculate my % from the displayed EV and Regen miles, I would get 2.4% for regen miles and 33.9% for EV miles which is way to low.   

[kostby]

@Plus3Golfer re: a 'low mileage car'

 

Not exactly sure what you're looking for, but here are stats:

 

Built April 10, 2013

We purchased it 03/26/2014 with 133 miles on the odometer.

Ford ETIS shows no software updates available, so apparently all applicable updates were done.

 

559.9 odometer miles on the car.

98% brake score

210.3 EV miles = 37.56% EV miles

26.7 regen miles = 4.768% regen miles

 

Snapshots of the rotor surfaces

Driver's side front disc

Driver's side rear disc

 

Passenger side front disc

 

Passenger side rear disc

Edited May 6, 2014 by kostby

[SnowStorm]

My regen miles is 3.6% with a 94% brake score and my EV miles is 50.7%.  My lifetime mpg is 42.0.

 

One anecdotal fact is that when I feel the surface of the front rotors compared to the rear rotors, the rear rotors have a slightly raised outer lip after 25k miles.  There is no perceived lip on the front rotors. Could this be friction braking wear on the rear?

My Regen is at 3.9% adding both before and after upgrade (remember Regen miles got reset).  EV is at 37.5% with lifetime miles at 31,731, 93% braking and 46.8 mpg (46.9 since upgrade - which is still biased with winter driving).  Our mileage has a lot at 55 mph and very little over 65 - using ethanol free gas.

 

My front discs are relatively smooth all the way across.  Rear ones are more uneven (slight ridges with the outer 25% looking like there was some rust there that has been mostly worn off by the pads).  There might be a tiny lip on the inside where the pads don't hit but it is almost undetectable (except for color).  Overall, front discs look a lot nicer but I don't know if it is from more use or less.

[ptjones]

Paul, just wondering if your regen miles and EV miles are since you owned the car or from the reset of those values which should have occurred with the 13B07 update.   My dealer SO shows the mileage on my vehicle when the update was performed.  If I inadvertently used the odometer miles to calculate my % from the displayed EV and Regen miles, I would get 2.4% for regen miles and 33.9% for EV miles which is way to low.

   

It appears my LifeTime was not reset. I have 80% HWY and that is why I have the numbers I have. I coast a lot so I should have a 20% Score so that is why  I think it scores the time you have your foot on the brake and the brake coach is spinning. :)

 

Paul

[plus 3 golfer]

Can you feel a raised lip on any of the flat surface rotor edges as you slide your finger across the rotor to the edge?  A new rotor is perfectly flat.  After rotors wear and since the pads don't extend to the surface, the edges will be raised slightly as the inner surface wears away.

 

[kostby]

At 559.9 miles, all the rotors are still perfectly flat, no raised lip.

[plus 3 golfer]

My Regen is at 3.9% adding both before and after upgrade (remember Regen miles got reset).  EV is at 37.5% with lifetime miles at 31,731, 93% braking and 46.8 mpg (46.9 since upgrade - which is still biased with winter driving).  Our mileage has a lot at 55 mph and very little over 65 - using ethanol free gas.

 

My front discs are relatively smooth all the way across.  Rear ones are more uneven (slight ridges with the outer 25% looking like there was some rust there that has been mostly worn off by the pads).  There might be a tiny lip on the inside where the pads don't hit but it is almost undetectable (except for color).  Overall, front discs look a lot nicer but I don't know if it is from more use or less.

My before reset % wwere close to my after but I didn't write down the numbers.  My rear rotors feel like you describe - slight ridges across the surface not perfectly smooth. My fronts feel virtually smooth. But again my rears have a very slight ridge on the edge and no ridge on the fronts.  The brake pads would likely be a better indicator of wear. But, I doubt I will ever have to change pads or rotors.  Next time I rotate tires I'll take a better look at everything - about 4-6 months from now.

 

.

[Zathrus]

Kostby...how do you display Lifetime Summary in instrument clustor (contained in you post above)? 

 

 

If there instructions in the manual on how to do this, I have not found it. Thanks.

[ptjones]

I looked at my rotors too and they are the same. The manual says regen is disabled when ABS is working, but by the looks of the rotors the computer figures in regen braking into the 70% front brakes and the rear brakes do more braking than the fronts. Maybe the front brakes only work in ABS Mode.  IMO :)

 

Paul

[plus 3 golfer]

Here's what the manual says below.  Regenerative braking is always active during normal braking including when friction brakes are used except when the battery is full and the anti-lock braking feature is activated (working) - to me means when ABS is preventing wheel lockup or other adverse condition.  I think it's simply a matter of semantics.  I always refer to the braking control systems as ABS to distinguish ABS equipped cars from cars that don't have ABS not whether the feature is being activated.  Normal operation of modern braking systems can proportion braking to front wheels and rear wheels.

 

 When the accelerator pedal is released or the brake pedal is applied, the

brake controller automatically detects the amount of deceleration

requested and optimizes how much of the deceleration will be produced

by regenerative braking. The remaining portion is generated by standard

friction braking. When the battery is almost fully charged, the amount of

regenerative braking is limited to avoid overcharging, and the requested

deceleration is produced by standard friction braking alone.

Regenerative braking does not take the place of the standard friction

brakes; it only assists them. Regenerative braking has also been designed

to interact with the anti-lock brake system. Regenerative braking is

disabled when the anti-lock brake system is activated or the battery is

fully charged.

 

 

 

[kostby]

@Zathrus

 

Lifetime Summary automatically displays after the ignition is turned off, but you have to be patient.

First the most recent trip statistics are shown.

Then, after a couple of moments, the lifetime stats appear for a few seconds, then the displays turn off.

 

 

Page 108 in the 2013 C-MAX Hybrid manual, 3rd printing

 

I have the SE, so I just turn off the key.

I'm not sure how it works in the pushbutton SEL.

Edited May 6, 2014 by kostby

[ptjones]

@Zathrus

 

Lifetime Summary automatically displays after the ignition is turned off, but you have to be patient.

First the most recent trip statistics are shown.

Then, after a couple of moments, the lifetime stats appear for a few seconds, then the displays turn off.

 

Screen Shot 2014-05-06 at 12.37.15 PM.png

 

Page 108 in the 2013 C-MAX Hybrid manual, 3rd printing

 

I have the SE, so I just turn off the key.

I'm not sure how it works in the pushbutton SEL.

It works the same. :)

 

Paul

[ScubaDadMiami]

I believe that I heard that there was a change where newer versions do not show the lifetime numbers. Maybe someone can verify this. My C-MAX does show this, but it is a year old.

[ptjones]

I believe that I heard that there was a change where newer versions do not show the lifetime numbers. Maybe someone can verify this. My C-MAX does show this, but it is a year old.

I believe the 2014 don't show this and people are disappoint because of it. I would be. ;)

 

Paul

[Zathrus]

@kostby...Thanks for info on Lifetime Summary. It appears ptjones and ScubaDadMiami are correct. I confirmed my later build (Aug 2013 SE) does not display Lifetime Summary (only Trip Summary). I now recall another thread awhile back indicating this feature was removed (not sure why). I guess I'll just keep using my Trip 2 Summary to keep track of lifetime stats.

Edited May 6, 2014 by Zathrus

[bemyax]

My 22 July 2013 SE does not have Lifetime Summary available, either. Thanks for the info on this.

[salsaguy]

Yes this really sucks. I just downloaded the 2014 manual and did a search for the word  lifetime and came  up with nothing :(

They probably removed it as many didn't know how to reset it and early driving miles by the owner learning how to drive  Hybrid led to early poor mpg numbers and then people complaining about it getting less than advertised mpg and then  posting bad reviews on the net and suing Ford.

 

 

I believe the 2014 don't show this and people are disappoint because of it. I would be. ;)

 

Paul

[MtnMarty]

What ever happened to Melinda?