Coasting mode

[Thomby]

As for the delay for coasting that could be due to both SoC and the fact that some of the requirements are that the transmission must be warmed up:
❈ The Eco-Coasting system works after the engine is turned on, the transmission is warmed up, and the engine sensor self diagnosis is completed after starting.

I pulled Transmission Temp into my JB4 app for some more anecdotal evidence. Yesterday after a 5min warmup and driving 3-4 miles I noticed I wasn't Coasting, but the transmission temp was about 99 degrees. At about the 6 mile mark I noticed it started coasting, and my transmission temp was in the 116-118 range. Not sure what's considered warmed up, but figured maybe there's a 110 or 115 degree minimum.

Today I went for another short drive, parked, then on the way home I sat for a few minutes before driving about 5 miles. So car was plenty warmed up (transmission ~140?), but Coasting never activated. So maybe it was the distance, or maybe the couple engine turnovers meant the battery hadn't topped back off, not sure.

Also checked coolant temp but it was hanging out right at 200, and JB4 doesn't display oil temp for me. I could see either of those being incorporated into an "everything is warmed up and operating normally" check.

Not sure what you're trying to say there. By 100kmh, you meant 100km/hr? With the inference that driving 100km/hr is boring?

Their mpg convention is liters per 100km, so he's just saying you'd have to drive 100km / 62 miles to see the 2.5 liters / 2/3 gallon savings.

 

[5tinger]

Coasting Mode on have had the Stinger since 2019 and have never noticed it coast or seen any indication of such on the dashboard.

 

[Volfy]

Not sure what you're trying to say there. By 100kmh, you meant 100km/hr? With the inference that driving 100km/hr is boring?...

Huh?

Yeah it does mean 100 km per hour......we changed back in 1970 from MPH to kmh like most of the rest of the world.

I will type slower this time......

Just because your speedometer shows 100kmh (or 62.15 mph..........) it is only for an instant......unless you drive 100 kilometres......for an hour. The displayed Litres/100km really doesn't mean much (or mpg).... Note the word metre and litre.........that's the English and correct spelling too. Just to be accurate.

No mention of being boring or any other interpretation.

and you mentioned earlier about only a small efficiency gain....as if you were some kind of expert.....you're not.

Look, if someone pissed on your cornflakes maybe it's better to calm down a bit rather than coming in here and rubbing people the wrong way......

Was that really necessary?! Perhaps giving some more thought before you reply would help others read you better... and could've avoided all this unpleasantry. I do hope you feel better after letting off some steam. There in Australia it's the middle of Summer right now, so hot temper flaring is understandable. I know... I was there Nov/Dec last year, working out of Barrow Island.






FWIW, the dash MPG displays I was referring to are not instant MPG. They are Trip AVERAGE MPG. On my '23, there are three(3) displays:

1. Trip Average Fuel Economy - this is a running average over the time/distance traveled since engine started. It auto-resets every time the ignition has turned OFF/ON.

2. Average Fuel Economy, since last refueling - this auto-resets every time ECU detects a substantial increase in fuel tank level.

3. Overall Trip Average Fuel Economy - running average, until driver manually resets.


For example, this screen shot shows the Trip Average Fuel Economy of 42.3 MPG over this particular drive distance of 24.6 miles, which is my commute route. This is the screen I drive on 95% of the time. On it, there is an instant fuel economy display, that is shown as a dynamic bar graph, It is also useful, but I don't always pay attention to that.

 

[Snicklefritz]

1. Trip Average Fuel Economy - this is a running average over the time/distance traveled since engine started. It auto-resets every time the ignition has turned OFF/ON.

Is the my23 different? Because in my earlier models it won't reset until the car has sat for four hours.

 

[Volfy]

Is the my23 different? Because in my earlier models it won't reset until the car has sat for four hours.

That's how my '19 does it. I actually prefer it that way. My '23 will reset every time the ignition is turned off and back on, which can be rather annoying. To me, a quick/short stop shouldn't reset the Trip Average MPG or mileage. I thought this might be an option buried in the vehicle settings somewhere, but I have not found it.

 

[Thomby]

Is the my23 different? Because in my earlier models it won't reset until the car has sat for four hours.

That's how my '19 does it. I actually prefer it that way. My '23 will reset every time the ignition is turned off and back on, which can be rather annoying. To me, a quick/short stop shouldn't reset the Trip Average MPG or mileage. I thought this might be an option buried in the vehicle settings somewhere, but I have not found it.

I usually leave it on the "since refueling" screen so not 100%, but pretty sure my 2022 reset any time the car is stopped, even if it's just a quick errand.

On the Coasting front, today I did another 5min warmup + 6-7 mile drive, and coasting didn't engage until the very end. Then did a quick gas station run before heading home, ie two startups with just a couple miles in between, and on the way home coasting kicked in just under 2.5 miles into the drive. So there doesn't seem to be a clear distance, time, or temp cutoff...maybe a combination of criteria in the algo.

 

[Ah GetFd]

Was that really necessary?! Perhaps giving some more thought before you reply would help others read you better... and could've avoided all this unpleasantry. I do hope you feel better after letting off some steam. There in Australia it's the middle of Summer right now, so hot temper flaring is understandable. I know... I was there Nov/Dec last year, working out of Barrow Island.

View attachment 83663




FWIW, the dash MPG displays I was referring to are not instant MPG. They are Trip AVERAGE MPG. On my '23, there are three(3) displays:

1. Trip Average Fuel Economy - this is a running average over the time/distance traveled since engine started. It auto-resets every time the ignition has turned OFF/ON.

2. Average Fuel Economy, since last refueling - this auto-resets every time ECU detects a substantial increase in fuel tank level.

3. Overall Trip Average Fuel Economy - running average, until driver manually resets.


For example, this screen shot shows the Trip Average Fuel Economy of 42.3 MPG over this particular drive distance of 24.6 miles, which is my commute route. This is the screen I drive on 95% of the time. On it, there is an instant fuel economy display, that is shown as a dynamic bar graph, It is also useful, but I don't always pay attention to that.
View attachment 83662

.....it's all good. Not a problem.

 

[5tinger]

How does one know coasting is active or not? I have coasting Mode turned on in the vehicle settings. However have never noticed any differences..

 

[Ah GetFd]

How does one know coasting is active or not? I have coasting Mode turned on in the vehicle settings. However have never noticed any differences..

I have a MY23 Stinger. When the drive mode is set to Eco the Eco symbol comes up in the centre display.

When the car is being driven on a slight decline at speed say 80kmh the message "coasting" comes up in the centre display to the right of the Eco symbol. You will feel the trans disconnect and reconnect when you either touch the brake or push the accelerator harder or the car hits an incline or flat and starts to slow.

The coasting tick box must be set in the setting under "Vehicle" then "drive mode"

 

[Thomby]

How does one know coasting is active or not? I have coasting Mode turned on in the vehicle settings. However have never noticed any differences..

When the car is being driven on a slight decline at speed say 80kmh the message "coasting" comes up in the centre display to the right of the Eco symbol. You will feel the trans disconnect and reconnect when you either touch the brake or push the accelerator harder or the car hits an incline or flat and starts to slow.

It can be in Eco, or in Smart during Eco driving conditions (Smart icon in green vs. white or red), or in Custom if you set engine/powertrain to Eco (suspension etc can be in comfort/sport).

You don't need to be on a decline, just within a +/-5% grade (ie not on a steep hill), and the minimum speed is 35mph for mine (56kph). Display may vary, but for my 2022, at the top of the dash display below, "Range 109 mi" would say "Coasting", and you feel the engine braking drag go away similar to taking a manual car out of gear:

 

[Audible Silence]

I drove 100 miles yesterday along back roads. lots of 60mph cruising and then coasting to a stop when there was a stop sign... coasting never engaged once. i remember reading somebody say they put it in sport mode for a few monutes and switch back to eco and it would work, but nothing i did yesterday would engage coasting. wonder if i "reset" the car by disconnecting the batter for a few would do anything...

 

[D.J.]

I drove 100 miles yesterday along back roads. lots of 60mph cruising and then coasting to a stop when there was a stop sign... coasting never engaged once. i remember reading somebody say they put it in sport mode for a few monutes and switch back to eco and it would work, but nothing i did yesterday would engage coasting. wonder if i "reset" the car by disconnecting the batter for a few would do anything...

Some conditions.


❈ If the front radar for smart cruise system cannot operate normally, the inter-vehicle distance and relative speed condition are automatically ignored.

❈ The Eco-Coasting system works after the engine is turned on, the transmission is warmed up, and the engine sensor selfdiagnosis is completed after starting.

❈ Depending on the driving situation, Eco-Coasting operation may be temporarily delayed even if the above conditions are
met.

 

[Ah GetFd]

I drove 100 miles yesterday along back roads. lots of 60mph cruising and then coasting to a stop when there was a stop sign... coasting never engaged once. i remember reading somebody say they put it in sport mode for a few monutes and switch back to eco and it would work, but nothing i did yesterday would engage coasting. wonder if i "reset" the car by disconnecting the batter for a few would do anything...

I wouldn't do a reset by removing the battery connection. Even doing a factory reset through the settings some things take a while to come back. I discovered this after a glitch on the daylight saving. You probably are not meeting some of the conditions.
Trying to make it do it is probably tougher. I don't try but I have indicated where it goes to coasting for me. It can be brief. Going downhill for example. As soon as the brake is touched coasting disappears. It "may" not operate if the hill is steeper.....which is why I mentioned a slight decline. So maybe the car detects uncommanded increasing speed and it doesn't work then either......coasting up to a Stop sign I think wouldn't be a way to kick this thing into working. Long straight drives with no-one around would be preferable.

 

[Thomby]

I'm still not clear on why mine wasn't working, but throwing a charger on the under hood jump points for an hour or two seemed to work.

As mentioned earlier in the thread, I did this because I was seeing 12.3ish volts with the car off, which I understand to be 50-60% charge vs. the expected 12.6v.

But even after a full charge and couple drives, I'd measure values like 12.4 after a bit of sitting, and Coasting still works, so I'm unclear on whether that was the requirement, and whether the Stinger uses any "smart" charge/discharge logic like I've read about for other cars...

 

[bfglitch]

and whether the Stinger uses any "smart" charge/discharge logic like I've read about for other cars...

I do recall seeing a thread quite a while ago where someone took voltage readings while driving and noticed that it only seemed to charge either while hitting the brakes, or maybe coasting (not sure about this type of coasting with the drivetrain decoupled). During his testing it didn't charge while hitting the accelerator. Can't recall which thread it was though.

 

[D.J.]

I do recall seeing a thread quite a while ago where someone took voltage readings while driving and noticed that it only seemed to charge either while hitting the brakes, or maybe coasting (not sure about this type of coasting with the drivetrain decoupled). During his testing it didn't charge while hitting the accelerator. Can't recall which thread it was though.

That was me, probably this post.
For clarification, higher charge voltage while decelerating (zero throttle), lower voltage while driving/accelerating (some throttle). - my car is a 2018, and does not have the Eco-coast feature.

Interesting Discoveries Thread (Good or Bad)

It might not be worth trying that out, unnecessary wear on the motor after all. The engine can take it. Kia built this powertrain to be as bullet proof as possible.

stingerforum.org

Note, the variable charge voltage observed in this video is NOT what I see daily. It occurs "sometimes" , and usually in the warmer seasons.



Recently, during colder weather, my voltages looks more like this image below, where voltage is basically consistent for the whole drive.

Voltage and coolant temperature plotted for about an hour.



Also, my battery resting voltage seems to be 12.1.... which does seem low!

 

[Thomby]

That's great info, makes sense it would disengage the alternator while accelerating and then engage it more fully on decel, as a sort of mini-regenerative braking. I assume Coasting disengages the alternator, so if the car thinks it needs to charge the battery, it won't coast.

Those low-12v resting voltages really throw me though, as everything I've read about AGM batteries is that they should have pretty much the same levels as standard flooded lead-acid. 12.1v is about half full.

 

[Ah GetFd]

Battery voltage is not a good way to determine if electronics are working. Firstly, electronics around the car should work on a lot less than 12 volts. I would guess 5 volts. A 12 volt battery is meant to perform its work from 12 volts which is its nominal voltage down to say 10.8 volts or 1.8 volts per cell. (6 cells in a 12V battery). After that your battery is considered to be discharged or "flat". It's probably around that voltage that the starter motor will no longer work but the battery will continue to provide voltage down to zero basically. (Like after leaving your headlights on)

The float or charge voltage above 12 volts (2.25 volts per cell (13.5V) to 2.4 volts per cell (14.4V) is wiped off very quickly when the alternator stops charging so it's not really considered as part of the usable voltage. The battery will settle very closely to its nominal voltage or 12 volts. Then it starts to do its work if a load is connected to it. If there is no load, then the internal resistance of the battery will discharge it slowly over two to three months.

The battery's only function really however, is to start the car. The battery should not contribute in any way to running the car whilst the engine is running as that would be discharging the battery. It's the alternator's job to recharge the battery and run the load so everything should run from the regulated alternator output.

So I doubt that the alternator is disconnected (via a clutch for example) whilst the engine is running unless someone has proven otherwise. And even if that were the case, the battery would be discharging and require recharging creating additional load on the engine so it would create more fuel use.

Comments as to differences between flooded and AGM batteries. Both are lead acid batteries with sulphuric acid electrolyte. Flooded as the same suggests is flooded with liquid. The AGM, meaning Absorbed Glass Fibre Mat, has "starved" electrolyte, so it is still liquid, but it is suspended in a blotting arrangement between the plates which is the AGM or.....Absorbed Glass Fibre Mat...... That's all.

Not to be confused with "Gel" batteries which are at the really cheap end of the spectrum, 5ah, 7ah, home alarm batteries and the like, (it's still sulphuric acic), and you will also find Gel in very long, slow discharge batteries like Solar for example that use a tubular plate inside (much like your shelf in a fridge), so they need Gel to get around the tubes of lead. So these are expensive and high Ah like 500ah.

The only other difference with an AGM Battery is that it is "Sealed" apart from a vent that operates only if the battery is accidentally overcharged, sometime called VRLA or "Valve" Regulated Lead Acid.

The only real way to determine if a battery is fully charged is to perform a discharge test on it then recharge it.

Assuming the battery is around 100 amp hours for this car and typically a battery is rated at the 10 hour rate down to an end voltage of 1.8 volts per cell (10.8 volts).

So what you do is find a load of 10 amps, maybe some 12V light bulbs on a board, so that they draw 10 amps, and run the battery down for 10 hours. The reading of the battery should be 10.8 volts. That confirms the battery was at full capacity.

Now charge it back up at 10 amps for 10 hours......with a charger. It is back to full capacity.

If you try a higher load to do this faster, you will get a lot less amphours out of the battery and a lot less time. You do not get 5 hours with a load of 20 amps for example. It does not work that way. You might only get 3 hours.....so then it would become a "60 amp hour battery"......

 

[Thomby]

Battery voltage is not a good way to determine if electronics is working. Firstly, electronics around the car should work on a lot less than 12 volts. I would guess 5 volts. A 12 volt battery is meant to perform its work from 12 volts which is its nominal voltage down to say 10.8 volts or 1.8 volts per cell. (6 cells in a 12V battery). After that your battery is considered to be discharged or "flat". It's probably around that voltage that the the starter motor will no longer work but the battery will continue to provide voltage down to zero basically. (Like after leaving your headlights on)

The float or charge voltage above 12 volts (2.25 volts per cell (13.5V) to 2.4 volts per cell (14.4V) is wiped off very quickly when the alternator stops charging so it's not really considered as part of the usable voltage. The battery will settle very closely to its nominal voltage or 12 volts. Then it starts to do its work if a load is connected to it. If there is no load, then the internal resistance of the battery will discharge it slowly over two to three months.

The battery's only function really however, is to start the car. The battery should not contribute in any way to running the car whilst the engine is running as that would be discharging the battery. It's the alternator's job. to recharge the battery and run the load so everything should run from the regulated alternator output.

So I doubt that the alternator is disconnected (via a clutch for example) whilst the engine is running unless someone has proven otherwise.

I don't know whether BMW's system involves an actual mechanical clutch, but modern alternators have voltage regulators that the ECU can modify (varying output, and by extension resistance), so it may be that their method of disengaging the alternator is to simply drop the output demand to zero and freewheel. Kia is probably doing something similar to produce the swings in voltage @D.J. is seeing based on accel/decel.

Regarding voltage, I'm aware that batteries will see a voltage sag if you put a load on them, but open circuit voltage is a very established measure of state of charge -- all the charts will tell you that, while the car may crank, at 12 volts you're over half empty. And even the 12.3-12.4 I was seeing is 70-80%, which for such a new car is suspect, unless Kia is doing it intentionally (for mileage, battery life, etc).

 

[D.J.]

Battery voltage is not a good way to determine if electronics are working.

Agreed. We are talking about battery voltage here, as it relates to the battery open circuit SoC (state of charge).

The battery's only function really however, is to start the car. The battery should not contribute in any way to running the car whilst the engine is running as that would be discharging the battery. It's the alternator's job to recharge the battery and run the load so everything should run from the regulated alternator output.

Typically, yes, but our cars have some subsystems which ONLY work if the battery SoC is above X%.
ISG for example, requires a minimum of 78% SoC for it to operate - so a weak or an uncharged battery will cause this system to stop working, with no fault codes. It is merely a condition of operation.
Kia Stinger: Engine Control / Fuel System / ISG (Idle Stop & Go) System - (Search for SoC)

Also - several people are hypothesizing that the ECO coast function may require a min SoC in order to function, though finding any documentation supporting this is proving to be difficult.

So I doubt that the alternator is disconnected (via a clutch for example) whilst the engine is running unless someone has proven otherwise. And even if that were the case, the battery would be discharging and require recharging creating additional load on the engine so it would create more fuel use.

100% correct, not disconnected via a clutch, but there is reduced voltage output based on driving conditions + battery state of charge.
When the car knows the battery has a high SoC, the AMS alternator management system, can reduce the voltage/load while cruising, and increase the voltage/load while decelerating.

•​	After reconnecting the negative battery cable, the AMS and ISG functions will not operate for about 4 hours until the system is stabilized.

The only real way to determine if a battery is fully charged is to perform a discharge test on it then recharge it

The no-load resting voltage really is "supposed" to be a reliable method to determine SoC.
Based on my cars build date (Feb 2018) - my battery is at least 2141 days or 70 months or 5.9 years old, so my open circuit resting voltage of 12.1v may be correct/expected for its age.

additional data from my 2018 stinger with OEM 90Ah AGM battery
During cranking, at 2°C (36°f), my voltage dips down to 8.2v - still cranks strong


Starting an already hot engine with coolant temp at 93°C (199°f), voltage dipped to 9.2v.


2018 stinger with OEM 90Ah AGM battery - Car build date was 02/2018