down hill coasting

[djc]

Interesting. 

There is a coolant temp sensor part listed various places for C-max hybrid, e.g.:

http://www.tascaparts.com/ford/c-max/3l8z12a648a/2013-year/hybrid-se-trim/2-0l-l4-electric-gas-engine/cooling-system-cat/water-pump-scat/?part_name=temp-sensor

 

Some household wireless thermometers have a sender with a little remote sensor that could be taped into a water pump discharge, radiator, or coolant hose, if one wanted a cheap dedicated temp gauge without running wire through firewall.  The (much) more ambitious could use a wired sensor in a Tee fitting spliced into a coolant hose....

[plus 3 golfer]

Interesting. 

There is a coolant temp sensor part listed various places for C-max hybrid, e.g.:

http://www.tascaparts.com/ford/c-max/3l8z12a648a/2013-year/hybrid-se-trim/2-0l-l4-electric-gas-engine/cooling-system-cat/water-pump-scat/?part_name=temp-sensor

 

Some household wireless thermometers have a sender with a little remote sensor that could be taped into a water pump discharge, radiator, or coolant hose, if one wanted a cheap dedicated temp gauge without running wire through firewall.  The (much) more ambitious could use a wired sensor in a Tee fitting spliced into a coolant hose....

 

That is likely for the auxiliary cabin heater on the Energi as there is an ECT sensor in that circuit.  It should not be confused with the CHT.

 

"A cabin heater coolant temperature sensor (also known as ECT sensor 2) in the cabin heater system [emphasis added] provides the PCM with coolant temperature information." 

Edited January 5, 2016 by Plus 3 Golfer

[stevedebi]

Interesting. 

There is a coolant temp sensor part listed various places for C-max hybrid, e.g.:

http://www.tascaparts.com/ford/c-max/3l8z12a648a/2013-year/hybrid-se-trim/2-0l-l4-electric-gas-engine/cooling-system-cat/water-pump-scat/?part_name=temp-sensor

 

Some household wireless thermometers have a sender with a little remote sensor that could be taped into a water pump discharge, radiator, or coolant hose, if one wanted a cheap dedicated temp gauge without running wire through firewall.  The (much) more ambitious could use a wired sensor in a Tee fitting spliced into a coolant hose....

I see Plus 3 beat me to it. The Energi model has a coolant temperature sensor used for the heating system when running in EV power. When the ICE is warmed up (at highway speeds or when the HVB is depleted and the Energi is in hybrid mode), the engine heat is used instead.

[BIG ROCCO]

It sure seems like it. LOL  But the Smart Gauge would show more gallons being used. Yesterdays fillup had Smart Gauge at 12.8 and actual was 13.85 gal.  I'm getting pretty good at coasting now. Last night I did 4 short trips for a total of 37.6 mi. and averaged 54mpg with temps from 32-36*F.  Amazing. :)

 

 

Empower Display shows instantaneous FE and Engineering Test Mode not practicable to use all the time.  

 

IMO The most important gauge for FE is an accurate WT gauge which the CMAX doesn't have unless you go into the engineering mode. You get the Best FE with WT above 202*F. I use IT, WT, TFT and SOC on my ScanGaugeII.  In my old pic I have instantaneous mpg.   :)

Paul - are you saying that you have tried coasting lately in N under certain circumstances, and you perceive a positive impact on MPG?  I noticed recently that in one downhill area where I usually coast and my speed increases somewhat, if I leave it in D, I have to us 1 to 1.5 bars of electric power just to maintain speed...so I have to believe N is more efficient than D...I am not recommending anyone else do it, nor am i commenting on it's legality, practicality, safety, or any other aspect...just talking about efficiency/impact on MPG

[stevedebi]

Paul - are you saying that you have tried coasting lately in N under certain circumstances, and you perceive a positive impact on MPG?  I noticed recently that in one downhill area where I usually coast and my speed increases somewhat, if I leave it in D, I have to us 1 to 1.5 bars of electric power just to maintain speed...so I have to believe N is more efficient than D...I am not recommending anyone else do it, nor am i commenting on it's legality, practicality, safety, or any other aspect...just talking about efficiency/impact on MPG

It is definitely more efficient to coast; all the best hypermilers do it. It just isn't legal in some states.

[SnowStorm]

Paul - are you saying that you have tried coasting lately in N under certain circumstances, and you perceive a positive impact on MPG?  I noticed recently that in one downhill area where I usually coast and my speed increases somewhat, if I leave it in D, I have to us 1 to 1.5 bars of electric power just to maintain speed...so I have to believe N is more efficient than D...I am not recommending anyone else do it, nor am i commenting on it's legality, practicality, safety, or any other aspect...just talking about efficiency/impact on MPG

So, you have a hill that causes the car to accelerate in N, but in D it needs 1 to 1.5 bars of EV power to keep the same speed?  I'm not trying to be difficult but would someone explain how that is possible - I don't see it.  If the hill is steep enough to accelerate the car, it should start regeneration when shifted to D.  As I understand it, there is no mechanical "neutral" - the same things are spinning (drive shafts, electric motors) or not (ICE) whether you are in N or D (EV mode).  The only difference is that regen can happen in D but not in N.

 

It is definitely more efficient to coast; all the best hypermilers do it. It just isn't legal in some states.

By "all the best hypermilers", are you including conventional cars or just hybrids?  I can certainly see the "need" for coasting with non-hybrids.  In hybrids, there would seem to be less of an advantage but there could still be some.  Motor/generators and power converters can be quite inefficient at light loads so it could be more efficient to coast, letting all the potential energy go directly into moving the car.

[Disclaimer: ;) I don't use it and don't suggest it - your laws may vary! :judge: ]

[ptjones]

Well I'm back from my 3900 mi trip to AZ and back.  I was able to do some Coasting Testing with varying road conditions and temps.  I can say without a doubt that coasting can improve FE by 5-10mpg under the right conditions. :shift: Here is a List of important points.

 

1. Regen Braking doesn't work in Neutral so when you step on the brakes you are actuating the real brakes wasting energy and brake pads and disks. :doh: If you need to brake shift back to Drive before applying the brakes.

 

2. You can inadvertently shift into Reverse which luckily doesn't change anything. Still you need to be careful not to do this. :doh:  

 

3. To do Coasting right you need the right conditions to make it work for you.

     a. Good road conditions, no rain or snow.

     b. Good weather conditions, no wind or tail wind.  Strong cross winds or head winds limit your ability to coast.

     c. Terrain needs to be level or down hill, hard to coast uphill.

   

4. I had my best results driving between Tucson and Phoenix, AZ with slight to no tailwind, temps 50-55*F with overall drop in elevation of 1300ft. for 90mi.

I filled up in El Paso, TX drove 265mi. to Tucson at which point my  FE was 38.5mpg due to headwind and 50*F temps.  By the time I got to Phoenix, 90 mi. later my average had gone to 43.5mpg's.  Doing the math I was getting about 58mpg between Tucson and Phoenix.

The technique I used was to follow a trucker going between 70-75mph and I would use a 2bar acceleration. Upon catching him I would let off the gas and shift to Neutral and coast down to 65mph. Then shift back to drive and 2bar accellerate back to the Semi, 75-80mph by that time, let off the gas again and shift to Neutral and coast to 65mph.

 

Pretty Amazing! :yahoo:  Unfortunately I wasn't able to do this for most of the trip because of the bad weather conditions. :sad:

 

Paul  

Edited January 10, 2016 by ptjones

[Bill-N]

2. You can inadvertently shift into Reverse which luckily doesn't change anything. Still you need to be careful not to do this. :doh:    

 

Hence my suggestion, in the changes-I'd-like-to-have forum, for trigger-less shifting from drive to neutral.

[ptjones]

Hence my suggestion, in the changes-I'd-like-to-have forum, for trigger-less shifting from drive to neutral.

It would be nice if there was something, to keep you from going into reverse. ;)

 

Paul

[stevedebi]

...

 

By "all the best hypermilers", are you including conventional cars or just hybrids?  I can certainly see the "need" for coasting with non-hybrids.  In hybrids, there would seem to be less of an advantage but there could still be some.  Motor/generators and power converters can be quite inefficient at light loads so it could be more efficient to coast, letting all the potential energy go directly into moving the car.

[Disclaimer: ;) I don't use it and don't suggest it - your laws may vary! :judge: ]

Oh, it will affect all vehicles, you just have to use it right and patiently learn what works. Wayne Gerdes is famous in the hypermiler world. He got in the mid 40's with the big Acura MDX.

[fbov]

Shifting is the wrong paradigm in a hybrid...

 

We want a throttle-foot-accessible "coast" mode, the elusive "no carat" state where the HVB has neither hat nor plinth.

 

Frank

[ptjones]

Shifting is the wrong paradigm in a hybrid...

 

We want a throttle-foot-accessible "coast" mode, the elusive "no carat" state where the HVB has neither hat nor plinth.

 

Frank

I'm sorry, but I didn't get that.  I have gotten use to shifting now and am seeing MPG's in the 50's with temps in the 30-low 40's. :)

 

Paul

[SnowStorm]

Shifting is the wrong paradigm in a hybrid...

 

We want a throttle-foot-accessible "coast" mode, the elusive "no carat" state where the HVB has neither hat nor plinth.

 

Frank

Agreed - except for "hat nor plinth"(?) - maybe "hat nor shoe" or "roof nor plinth" ...

Anyway, it would indeed be nice to have a manual "no regen" mode:

1. Use paddle shifters to bump up/down the strength of regen - 0 to 35kW for "no throttle" condition
2. Have three settings selectable on the shifter button
3. Some other On/Off regen switch

Or perhaps even better, have a third Super-Eco-Cruise Control ("Coast-N-Cruise" anyone?) that allows the car to speed up with no regen to a maximum (selectable) overspeed value before regen cuts in.  So, you might have CC at 65 mph, car starts down a hill that is increasingly steep, ICE shuts OFF, applied EV power goes to zero, car speeds up to say 70 with no regen, regen is then used to hold at 70, ICE spins up if regen can't hold 70 (DHA selected).  If Coast-N-Cruise is selected but not engaged, then there is never any "off throttle" regen (until you hit the brakes, of course).

[SnowStorm]

Well I'm back from my 3900 mi trip to AZ and back.  I was able to do some Coasting Testing with varying road conditions and temps.  I can say without a doubt that coasting can improve FE by 5-10mpg under the right conditions. .....

So you drove without any coasting for 265 miles and got 38.5 MPG.  Then you drove 90 miles with less headwind, 1300ft elevation drop, drafting a truck, slight increase in temperature and coasting - and the credit goes to coasting?  I don't think its a fair comparison.

 

OTOH, it looks like your mileage for the 90 miles should be 70 MPG.  265 miles at 38.5 mpg is 6.883 gallons.  Total trip is (265+90)/43.5 = 8.161 gallons.  Mileage for last 90 miles is 90/(8.161-6.883) = 70 MPG!

[stevedebi]

Agreed - except for "hat nor plinth"(?) - maybe "hat nor shoe" or "roof nor plinth" ...

Anyway, it would indeed be nice to have a manual "no regen" mode:

1. Use paddle shifters to bump up/down the strength of regen - 0 to 35kW for "no throttle" condition
2. Have three settings selectable on the shifter button
3. Some other On/Off regen switch

Or perhaps even better, have a third Super-Eco-Cruise Control ("Coast-N-Cruise" anyone?) that allows the car to speed up with no regen to a maximum (selectable) overspeed value before regen cuts in.  So, you might have CC at 65 mph, car starts down a hill that is increasingly steep, ICE shuts OFF, applied EV power goes to zero, car speeds up to say 70 with no regen, regen is then used to hold at 70, ICE spins up if regen can't hold 70 (DHA selected).  If Coast-N-Cruise is selected but not engaged, then there is never any "off throttle" regen (until you hit the brakes, of course).

On the manual regen control: Oh no, never going to happen. Ford has to predict how the battery is going to be charged/discharged. They won't allow that much control by design.

 

For the Energi (doesn't apply to the hybrid, of course), I've often wished for control of the EV setting on the sifter, there is room for another triangle button above the grade assist button. But Ford doesn't want folks playing around with that either. The car is designed to go into one mode and stay there. They don't want to encourage folks to "game" the system in any way. They want to control how the battery, eCVT, and engine interact.

[fbov]

Agreed - except for "hat nor plinth"(?) - maybe "hat nor shoe" or "roof nor plinth"

Let's see... in statistics, a "^" above a variable indicates a predicted value, Y-hat. Plus, "^" kind of looks like a hat.

 

I had a heck of a time finding an image for the plinth that in any way resembled what my mind's eye saw... at least a plinth goes in the right place, underneath.

 

Frank

[BIG ROCCO]

Yes, if you accidentally shift into R with the car moving forward, there is absolutely no noticeable ill effect...interestingly, the rear view/back up camera displays if so equipped.  Also, I think I noticed the throttle pedal has the opposite effect from normal - the more you step on the pedal, the slower the car goes, but I am not 100% on that.

 

I think the explanation why going down a hill in D would require some added EV energy input to maintain speed, but the car will increase speed in N is that shifting to N somehow disengages certain gears in the trans and those items have enough frictional losses to slow the car down in D.

 

For what it's worth, I might come across a place to coast 1-2 times a day.  I do not do it a lot, like Paul did on his recent trip to Phoenix (but I'm not being critical of what he did either).  I guess if i think about it, I would say I like to coast where there is a long, gradual to moderate grade...gradual enough to require feathering the throttle just to maintain speed, and not so steep that the car will increase in speed excessively, and with a level or uphill area at the bottom (so no stop sign/red light) .  Also, if I am on a known mountain road with a cross section similar to an inverted U or V, I might like to approach the summit at a slow speed (ex: 55MPH on a 65MPH road), shift to N at or near the summit, then coast until the car reaches ~ the speed limit (60-65MPH) and then shift back into D and let the downhill charge the HV battery.  I only do this on roads I know well, because it is not always effective or even safe to do.

[SnowStorm]

On the manual regen control: Oh no, never going to happen. Ford has to predict how the battery is going to be charged/discharged. They won't allow that much control by design.

If so, than Ford had better check out the upcoming competition!  The new Chevy Bolt is to have the following functions which seem like quite a bit of manual control.

 

Regen System Provides One-Pedal Driving

"Regenerative braking has become more than just a tool to boost range, it’s also transformed into a feature that can provide an improved EV driving experience.  The Bolt EV features a new regenerative braking system that has the ability to provide one pedal driving.

“Interviews with EV enthusiasts indicated their desire for one pedal driving capability on the Bolt EV.  One pedal operation boosts the thrill and uniqueness of EV driving,” Tavel said.

Through a combination of increased regenerative deceleration and software controls, one pedal driving enables the vehicle to slow down and come to a complete stop without using the brake pedal in certain driving conditions. 

When operating the Bolt EV in “Low” mode, or by holding the Regen on Demand paddle located on the back of the steering wheel, the driver can bring the vehicle to a complete stop under most circumstances by simply lifting their foot off the accelerator, although the system does not relieve the need to use the brake pedal altogether. 

Operating the Bolt EV in “Drive” mode and not pulling the paddle while decelerating delivers a driving experience where usage of the brake pedal is required to stop."

[stevedebi]

If so, than Ford had better check out the upcoming competition!  The new Chevy Bolt is to have the following functions which seem like quite a bit of manual control.

 

Regen System Provides One-Pedal Driving

"Regenerative braking has become more than just a tool to boost range, it’s also transformed into a feature that can provide an improved EV driving experience.  The Bolt EV features a new regenerative braking system that has the ability to provide one pedal driving.

“Interviews with EV enthusiasts indicated their desire for one pedal driving capability on the Bolt EV.  One pedal operation boosts the thrill and uniqueness of EV driving,” Tavel said.

Through a combination of increased regenerative deceleration and software controls, one pedal driving enables the vehicle to slow down and come to a complete stop without using the brake pedal in certain driving conditions. 

When operating the Bolt EV in “Low” mode, or by holding the Regen on Demand paddle located on the back of the steering wheel, the driver can bring the vehicle to a complete stop under most circumstances by simply lifting their foot off the accelerator, although the system does not relieve the need to use the brake pedal altogether. 

Operating the Bolt EV in “Drive” mode and not pulling the paddle while decelerating delivers a driving experience where usage of the brake pedal is required to stop."

Well, Ford doesn't particularly care about cutting edge. Their constant concern with the hybrids, for 10 years now, is to make sure they perform for the lifetime of the car, and they carefully control all possible parameters to make that happen.

 

But that system is simply engaging more regen when you lift off the pedal. I think that our "L" mode basically does that to some extent - when you let off the accelerator, the car starts regen. The Bolt also uses active cooling for the battery, which allows for more flexibility in regen.

 

Reminds me of the "go carts" I used when I was a child; they had only one pedal and you were either going or stopping.

[raadsel]

If so, than Ford had better check out the upcoming competition!  The new Chevy Bolt is to have the following functions which seem like quite a bit of manual control.

 

Regen System Provides One-Pedal Driving

"Regenerative braking has become more than just a tool to boost range, it’s also transformed into a feature that can provide an improved EV driving experience.  The Bolt EV features a new regenerative braking system that has the ability to provide one pedal driving.

“Interviews with EV enthusiasts indicated their desire for one pedal driving capability on the Bolt EV.  One pedal operation boosts the thrill and uniqueness of EV driving,” Tavel said.

Through a combination of increased regenerative deceleration and software controls, one pedal driving enables the vehicle to slow down and come to a complete stop without using the brake pedal in certain driving conditions. 

When operating the Bolt EV in “Low” mode, or by holding the Regen on Demand paddle located on the back of the steering wheel, the driver can bring the vehicle to a complete stop under most circumstances by simply lifting their foot off the accelerator, although the system does not relieve the need to use the brake pedal altogether. 

Operating the Bolt EV in “Drive” mode and not pulling the paddle while decelerating delivers a driving experience where usage of the brake pedal is required to stop."

 

I recall the BMW i3 operates that way by design. The brake pedal in that car is solely for the physical brake pads and really only needs to be used if regenerative braking can't stop you quickly enough or on an incline.  

[BIG ROCCO]

I like the idea of the regen on demand paddle - it means you know all deceleration (actually, I think "negative acceleration" is technically more correct) is coming from regen...also, I wonder if the brake lights illuminate when using that paddle...???  Whenever possible, I like to apply the brakes very lightly for a long period to maximize regen, but sometimes I feel a little self conscious that people behind me think I am moping and riding the brakes (when I actually barely have them applied)

[ptjones]

SnowStorm, on 12 Jan 2016 - 12:42 AM, said:

So you drove without any coasting for 265 miles and got 38.5 MPG.  Then you drove 90 miles with less headwind, 1300ft elevation drop, drafting a truck, slight increase in temperature and coasting - and the credit goes to coasting?  I don't think its a fair comparison.

You can't do much Drafting if you are using Coasting to the max, you are only in drafting range about 1/4 of the time.  The wind and speed where the main problems for the first part of the trip so not having the head wind diffidently helped MPG's.  I did do some drafting on the El Paso to Tucson part of the trip, I can't help myself when the opportunity presents itself. LOL  I forgot about coasting until I got through Tucson.

 

OTOH, it looks like your mileage for the 90 miles should be 70 MPG.  265 miles at 38.5 mpg is 6.883 gallons.  Total trip is (265+90)/43.5 = 8.161 gallons.  Mileage for last 90 miles is 90/(8.161-6.883) = 70 MPG!   I just figured the difference so thanks for setting me strait.  :)

Paul

Edited January 12, 2016 by ptjones

[stevedebi]

I like the idea of the regen on demand paddle - it means you know all deceleration (actually, I think "negative acceleration" is technically more correct) is coming from regen...also, I wonder if the brake lights illuminate when using that paddle...???  Whenever possible, I like to apply the brakes very lightly for a long period to maximize regen, but sometimes I feel a little self conscious that people behind me think I am moping and riding the brakes (when I actually barely have them applied)

Can't speak to the BMW, but the Tesla does activate the brake lights when the regen kicks in, from my reading.

[ptjones]

I have learned a few more things about coasting, it cools down the HVB so I see 2 bar EV when I use it. The  ICE runs cooler too. I have been watching the SOC when using ICE going uphill, the charging system barely charges when above above 2 bars,sometimes not at all. It is surprising to go uphill for a long time and then at the top of the hill

HVB SOC has hardly changed from when you started up the hill. ;) Today I drove into Atlanta and back on I-85 and averaged 56.6mpg with rain on the way back and 60*F. I did some coasting. :)

 

Paul

Edited February 24, 2016 by ptjones

[BIG ROCCO]

Paul - I find it kind of amusing that I turned you into a "coaster".  My initial post was simply to respond to a previous post and say that coasting in N seems like it would be the most direct and therefore most efficient way to harvest the stored energy at the top of a hill.  Yes, I do it sometimes, maybe 1-2 times a day, but I wasn't advocating that anyone else do it.  Nevertheless, I am happy learn that you are enjoying the technique and have noticed an MPG advantage in doing so, even if it might ne illegal or unsafe as some others have pointed out.