FEH High Voltage Battery Level
#21
04-15-2009, 05:08 PM
Re: FEH High Voltage Battery Level
Yeah, been there. Got it and think I know how to use it.
Many thanks.
Many thanks.
#22
04-15-2009, 06:55 PM
Re: FEH High Voltage Battery Level
Sounds like you might have been in "L" for engine braking. That is how mine behaves when there is no more "room" in the battery and the braking has to be doe somewhere else, like compression braking by the engine.
It very rarely does this when in "D," even on long grades.
True?
It very rarely does this when in "D," even on long grades.
True?
I don't think the phenomenon that you describe as compression braking is exactly that at all. I believe that the ice is being spun by the motor to "burn off" excess charge. I say that because when the ice takes off on a tear like that from overcharge, the vehicle can be at a dead stop, or be brought to a dead stop, and the can still be whizzing away.
#23
04-15-2009, 08:03 PM
Hybrid and Ethanol Expert
Join Date: Mar 2005
Location: All over the Central U.S.
Posts: 3,616
Re: FEH High Voltage Battery Level
Bill, What is your question?
Pose a lucid, intellegent question, and I will give the what you would like to know. I posted 100% accurate information about the 2005-2008 Ford Escape Battery pack and its control software. What would you like to know?
Either the 4 vehicles I have driven, disassembled, and studied are "unique" or, since all 4 behaved the same way, they are typical of how the Ford Escape Hybrid operates. My credentials are below Ford's but far out weigh yours in this area of expertise.
So now ask a valid question or get off the proverbial pot.
Thanks.
Pose a lucid, intellegent question, and I will give the what you would like to know. I posted 100% accurate information about the 2005-2008 Ford Escape Battery pack and its control software. What would you like to know?
Either the 4 vehicles I have driven, disassembled, and studied are "unique" or, since all 4 behaved the same way, they are typical of how the Ford Escape Hybrid operates. My credentials are below Ford's but far out weigh yours in this area of expertise.
So now ask a valid question or get off the proverbial pot.
Thanks.
As long as the FEH is moving forward under power and running on the ICE it should not make a difference in those numbers. But it would be interesting to know if it did. The manuals advertise "L" as only increasing the charging output to the traction battery when braking or coasting.
From the 68.6% SOC above I infer that the charge discharge cycle when underway (instead of curbside) is a broader range. My guesstimate from experience watching submarine batteries (different chemistry) over the years is that the underway curves of charge & discharge is about 30-40% to about 70-80%.
So the bottom end isn't too far off but we'll have to refine the top end a bit.
This is just based on my behind the wheel observation of the system.
From the 68.6% SOC above I infer that the charge discharge cycle when underway (instead of curbside) is a broader range. My guesstimate from experience watching submarine batteries (different chemistry) over the years is that the underway curves of charge & discharge is about 30-40% to about 70-80%.
So the bottom end isn't too far off but we'll have to refine the top end a bit.
This is just based on my behind the wheel observation of the system.
#24
04-15-2009, 08:14 PM
Hybrid and Ethanol Expert
Join Date: Mar 2005
Location: All over the Central U.S.
Posts: 3,616
Re: FEH High Voltage Battery Level
People get confused with wording.
"Compression brake" is just that.
It does not matter if the wheels are spinng the engine without fuel, the engine acting as an air compressor, or if the traction motor is putting resistance on the wheels, generating power, sending the power to the generator, and then in turn, the generator spins the engine without fuel, acting as an air compressor.
The FEH still has 'engine compression braking' just in a more complicated way.
HTH,
-John
"Compression brake" is just that.
It does not matter if the wheels are spinng the engine without fuel, the engine acting as an air compressor, or if the traction motor is putting resistance on the wheels, generating power, sending the power to the generator, and then in turn, the generator spins the engine without fuel, acting as an air compressor.
The FEH still has 'engine compression braking' just in a more complicated way.
HTH,
-John
#25
04-15-2009, 08:45 PM
Re: FEH High Voltage Battery Level
People get confused with wording.
"Compression brake" is just that.
It does not matter if the wheels are spinng the engine without fuel, the engine acting as an air compressor, or if the traction motor is putting resistance on the wheels, generating power, sending the power to the generator, and then in turn, the generator spins the engine without fuel, acting as an air compressor.
The FEH still has 'engine compression braking' just in a more complicated way.
HTH,
-John
"Compression brake" is just that.
It does not matter if the wheels are spinng the engine without fuel, the engine acting as an air compressor, or if the traction motor is putting resistance on the wheels, generating power, sending the power to the generator, and then in turn, the generator spins the engine without fuel, acting as an air compressor.
The FEH still has 'engine compression braking' just in a more complicated way.
HTH,
-John
#26
04-15-2009, 08:49 PM
Re: FEH High Voltage Battery Level
No argument that the system uses the engines compression for braking.
I am not convinced that the phenomenon where the ice runs up to burn off excess soc can be called compression braking. Seems to me that in those situations the ice speed is independant from the vehicle speed.
Different situation.
I am not convinced that the phenomenon where the ice runs up to burn off excess soc can be called compression braking. Seems to me that in those situations the ice speed is independant from the vehicle speed.
Different situation.
#27
04-16-2009, 03:34 AM
Re: FEH High Voltage Battery Level
gpsman1: Didn't pose a question, sorry.
Experience combined with anecdotal information does not equal credentials.
Please send your credentials in a private message.
Experience combined with anecdotal information does not equal credentials.
Please send your credentials in a private message.
#28
04-16-2009, 06:33 AM
Re: FEH High Voltage Battery Level
Keep in mind that the computer controller can spin the ICE at what ever speed it selects.
The energy of coasting downhill has to go somewhere. Vehicle speed increase, battery charging, or engine friction and compression (note that engine internal friction is a smaller part of engine braking or compression braking).
In my observation when in "L," and when the battery has attained a certain state of charge, the controller spins the ICE up and it absorbs the energy of braking. I have seen the engine at about 2500 to 3000 rpm and also at around 4,000 rpm.
My take is that the software is programmed to set the engine where it gives the requisite braking (ie rpm setting & fuel setting) for the counter-torque being demanded. The characteristics of this are different when in "L" than when in "D." In "L" it comes on much more readily.
I suspect that is just how Ford intended "L" to be used since, by the manual, it does not add to the power on mode, only the power off or coasting mode (& I don't mean engine off but simply foot off the gas pedal & coasting).
The energy of coasting downhill has to go somewhere. Vehicle speed increase, battery charging, or engine friction and compression (note that engine internal friction is a smaller part of engine braking or compression braking).
In my observation when in "L," and when the battery has attained a certain state of charge, the controller spins the ICE up and it absorbs the energy of braking. I have seen the engine at about 2500 to 3000 rpm and also at around 4,000 rpm.
My take is that the software is programmed to set the engine where it gives the requisite braking (ie rpm setting & fuel setting) for the counter-torque being demanded. The characteristics of this are different when in "L" than when in "D." In "L" it comes on much more readily.
I suspect that is just how Ford intended "L" to be used since, by the manual, it does not add to the power on mode, only the power off or coasting mode (& I don't mean engine off but simply foot off the gas pedal & coasting).
#29
04-16-2009, 04:43 PM
Re: FEH High Voltage Battery Level
Here is a statement I made on the FEH Yahoo site and a PM from a Ford FEH Engineer:
> I've been saying all along that the FEH does not have real engine
> braking. In fact, another Ford patent explains that Ford Engineers
did
> not want to allow engine braking to take away from the benefits of
> regenerative braking. This does not mean the one-way clutch can't
> allow real engine braking through programming though, it just means
it
> may be a last choice.
Ford FEH Engineer:
As with many of the sweeping statements made
about the FEH system behavior, one
must he careful to qualify whether a
statement applies to the 0-40�mph range
when ICE may be off or potentiality
could shutdown and the range above
40 mph where ICE is always spinning. The above statement is correct
below 40 but wrong above 40. Clearly you don't
want to waste battery power by having the
traction motor turning the ICE when
driving the vehicle forward. That's the
situation under 40�mph. But above 40 its a
whole different control regime.
My '09 FEH has a completely different control regime than the '05 - '08 FEH.
GaryG
> I've been saying all along that the FEH does not have real engine
> braking. In fact, another Ford patent explains that Ford Engineers
did
> not want to allow engine braking to take away from the benefits of
> regenerative braking. This does not mean the one-way clutch can't
> allow real engine braking through programming though, it just means
it
> may be a last choice.
Ford FEH Engineer:
As with many of the sweeping statements made
about the FEH system behavior, one
must he careful to qualify whether a
statement applies to the 0-40�mph range
when ICE may be off or potentiality
could shutdown and the range above
40 mph where ICE is always spinning. The above statement is correct
below 40 but wrong above 40. Clearly you don't
want to waste battery power by having the
traction motor turning the ICE when
driving the vehicle forward. That's the
situation under 40�mph. But above 40 its a
whole different control regime.
My '09 FEH has a completely different control regime than the '05 - '08 FEH.
GaryG
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