PHEVs to Rule Trucks?

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EDM will engage when the battery is depleted, or at 2 bars on the gauge. SOC is irrelevant. Speed needs to be at or above 45mph AND torque needs to remain in a very narrow band in order for EDM to engage and remain engaged. It’s that simple.
That's not true, try getting the SOC down to 1 bar, it won't go into engine drive mode. Engine drive mode will not engage below approximately 7% SOC. Also, it's about 43.5mph, not 45, and the torque is actually a VERY wide band, in eco mode unless you go beyond the click point it can stay in engine drive mode.
 
I understand that EDM cannot work when the battery is depleted. EDM still uses both the motor/generator to produce some power to the HV battery and the HV battery to supply some power to the traction motor. This setup allows the HV battery to provide some energy when the vehicle needs to accelerate in EDM. The PCU carefully controls the whole system to maintain optimum efficiency. So, EDM needs the HV battery to be able to provide some energy and the PCU will not let the HV battery do when the SOC gets too low (depleted). When the HV battery is depleted, the PCU switches to an HV mode where the engine can generator with increased output to charge the HV battery. This is not guess work on my part. There is an explanation of how the EDM works in Honda's SAE article on the "Development of Electric Powertrain for CLARITY PLUG-IN HYBRID."
 
I understand that EDM cannot work when the battery is depleted. EDM still uses both the motor/generator to produce some power to the HV battery and the HV battery to supply some power to the traction motor. This setup allows the HV battery to provide some energy when the vehicle needs to accelerate in EDM. The PCU carefully controls the whole system to maintain optimum efficiency. So, EDM needs the HV battery to be able to provide some energy and the PCU will not let the HV battery do when the SOC gets too low (depleted). When the HV battery is depleted, the PCU switches to an HV mode where the engine can generator with increased output to charge the HV battery. This is not guess work on my part. There is an explanation of how the EDM works in Honda's SAE article on the "Development of Electric Powertrain for CLARITY PLUG-IN HYBRID."
It's also something that can be proven with data and the inner workings of the ECU. Sidenote, the PCM is not in the slightest concerned about how the hybrid system is coordinated, all the PCU does is control both electric motors to meet the torque demanded by the ECU (quite a daunting task, the way the motors are controlled is so obscenely complex that it makes my head hurt). The ECU, or more accurately PCM is what coordinates the drivetrain.
 
I think I'd pay to end this thread. Certainly don't think it has been worth my headache from it. I'd bet that the RamCharger will be a great vehicle. I'd also bet that the ICE is appropriately sized for the duty of the typical truck owner based on all I've read, and maybe even for the extreme needs that some will place on it. I'd bet it is better suited to long range towing than other EV options and that it will get great reviews when it is available. I also believe that the ICE in the Honda Clarity is appropriately sized for the needs of the typical owner. I love getting essentially 50 mpg when driving it in hybrid mode on long trips and can't imagine how it could be much more efficient without cutting the size (weight) of the battery and I wouldn't give that up. It is wise to not to expect the Clarity to perform great with a depleted battery, and generally that condition is avoidable if one plans ahead at all, but you can't keep either the uneducated or the ill-prepared from occasionally doing that and complaining about it. Could a situation drive you to have to endure a depleted battery at a time when high hp is needed even if you prepared as best you can? Maybe, but I haven't had it happen yet in nearly 6 years.
I may be in the minority here when I say this, but I believe it is best that vehicles behave predicably and within reasonable expectations of performance, without needing a nerd behind the wheel who knows how it all works.
 
Yes, I should have written PCM (located to the rear of the 12V battery) instead of the PCU. Mea Culpa. LP
 
try getting the SOC down to 1 bar, it won't go into engine drive mode.

I tried, for nearly 5 years after reading about the phenomenon on this forum. It never happened for me. This included a trip where the battery was depleted to 2 bars within the first 25 miles while traveling south on I-5 over the Siskiyou Pass and into the mountains of N Cal. This was during the first week of ownership, and not being familiar with the vehicle, I just got in and drove.

While fueling up near Redding, after buzzing over mountain passes on 2 bars, at 70mph for the previous 2 hours, I read a part of the manual on HV Charge and engaged that to get the battery to roughly 50% for the remainder of the 700 mile drive. Never saw 1 bar on that trip, and I never figured out how to get it to 1 bar.

Also, it's about 43.5mph, not 45, and the torque is actually a VERY wide band, in eco mode unless you go beyond the click point it can stay in engine drive mode.

This is, in my experience, a narrow band. At any speed when EDM may engage, it must also be in, and remain in a limited range of torque relative to that speed. I operated the vehicle exclusively in ECO and never pushed the accelerator beyond the “click point”. That said, I could get EDM to disengage easily and consistently with anything more than the slightest amount of acceleration. On one occasion, an opportunity presented itself to ever so gently accelerate while in EDM and I managed to achieve a speed of 85mph.

My actual experience with the vehicle doesn’t align perfectly with your data. I’ve observed the power flow screen while EDM is engaged and it occasionally shows the generator charging the battery while the engine is directly driving the wheels. Of course this has always occurred with 2 or more bars remaining on the battery gauge, but it appears to demonstrate that EDM can propel the vehicle without assistance from the battery and motor.

Also, I had mistakenly presumed that since we were tossing around terms such as “too low” “very wide” “narrow”, etc, that 45mph might be considered “close enough”.IMG_3522.webp
 
I tried, for nearly 5 years after reading about the phenomenon on this forum. It never happened for me. This included a trip where the battery was depleted to 2 bars within the first 25 miles while traveling south on I-5 over the Siskiyou Pass and into the mountains of N Cal. This was during the first week of ownership, and not being familiar with the vehicle, I just got in and drove.

While fueling up near Redding, after buzzing over mountain passes on 2 bars, at 70mph for the previous 2 hours, I read a part of the manual on HV Charge and engaged that to get the battery to roughly 50% for the remainder of the 700 mile drive. Never saw 1 bar on that trip, and I never figured out how to get it to 1 bar.



This is, in my experience, a narrow band. At any speed when EDM may engage, it must also be in, and remain in a limited range of torque relative to that speed. I operated the vehicle exclusively in ECO and never pushed the accelerator beyond the “click point”. That said, I could get EDM to disengage easily and consistently with anything more than the slightest amount of acceleration. On one occasion, an opportunity presented itself to ever so gently accelerate while in EDM and I managed to achieve a speed of 85mph.

My actual experience with the vehicle doesn’t align perfectly with your data. I’ve observed the power flow screen while EDM is engaged and it occasionally shows the generator charging the battery while the engine is directly driving the wheels. Of course this has always occurred with 2 or more bars remaining on the battery gauge, but it appears to demonstrate that EDM can propel the vehicle without assistance from the battery and motor.

Also, I had mistakenly presumed that since we were tossing around terms such as “too low” “very wide” “narrow”, etc, that 45mph might be considered “close enough”.View attachment 23052
One of the easiest ways to get the battery down to one bar is to be stationary, the SOC will dip down to 1% before the clarity starts the engine. You can use the AC or heater or another accessory to speed up this process. I can record a video if you wish. I find it very strange that for you engine drive mode disengages if you slightly press the accelerator pedal. For me, the battery will output up to 70kw-90kw or so of assistance in engine drive mode. You sure your not mistaking the engine driver mode with something else? Perhaps you could record an OBD2 log?
 
I understand that EDM cannot work when the battery is depleted. EDM still uses both the motor/generator to produce some power to the HV battery and the HV battery to supply some power to the traction motor. This setup allows the HV battery to provide some energy when the vehicle needs to accelerate in EDM. The PCU carefully controls the whole system to maintain optimum efficiency. So, EDM needs the HV battery to be able to provide some energy and the PCU will not let the HV battery do when the SOC gets too low (depleted).

Thanks for that. I’ve read the article as well, including the parts about using the HV battery while EDM is engaged. As mentioned previously, I’ve also observed EDM operating without input from the HV battery. And I’ve observed the battery being charged while EDM is engaged.

In my experience “depleted” is 2 bars and I’ve never experienced “too low”.
 
Thanks for that. I’ve read the article as well, including the parts about using the HV battery while EDM is engaged. As mentioned previously, I’ve also observed EDM operating without input from the HV battery. And I’ve observed the battery being charged while EDM is engaged.

In my experience “depleted” is 2 bars and I’ve never experienced “too low”.
2 bars is only depleted from the point of view of charge deplete mode, from the point of charge sustain mode 2 bars is ideal. Sidenote, engine drive mode *always* had either input or output from or into the battery, the drive mode screen simplifies it to prevent "flickering". A few kw in or out will show up as only the engine driving the wheels, without anything going into or out of the battery, despite this not being the case.
 
One of the easiest ways to get the battery down to one bar is to be stationary, the SOC will dip down to 1% before the clarity starts the engine. You can use the AC or heater or another accessory to speed up this process. I can record a video if you wish. I find it very strange that for you engine drive mode disengages if you slightly press the accelerator pedal. For me, the battery will output up to 70kw-90kw or so of assistance in engine drive mode. You sure your not mistaking the engine driver mode with something else? Perhaps you could record an OBD2 log?

Would one need to be stationary while in EV Mode to achieve this goal? My experience with the vehicle in HV Mode is that it will attempt to maintain the SOC set point.

We sold the car a few months ago, so a video demonstration of the battery depleting process isn’t necessary. I’ve never been one to sit in a parked car for extended periods of time anyhow. I also never used an OBD device during our ownership of the car. Some who have done so have reported that a 4% drop in SOC will trigger the ICE to restore the battery, when in HV Mode.

I can also assure you that I was not mistaking EDM for something else.
 
Would one need to be stationary while in EV Mode to achieve this goal? My experience with the vehicle in HV Mode is that it will attempt to maintain the SOC set point.

We sold the car a few months ago, so a video demonstration of the battery depleting process isn’t necessary. I’ve never been one to sit in a parked car for extended periods of time anyhow. I also never used an OBD device during our ownership of the car. Some who have done so have reported that a 4% drop in SOC will trigger the ICE to restore the battery, when in HV Mode.

I can also assure you that I was not mistaking EDM for something else.
Go to 2 bars of battery, and just be stationary for an extended period of time, eventually the soc will drop to 1 bar. Another way to get the car to have 1 bar is to accelerate aggressively, put the car in neutral, come to a stop, and repeat many times. Charge sustain mode will attempt to maintain the SoC, and it does do that, but when stationary it *hates" running the engine. There have been times where after sitting in the car for half an hour or so with the AC then driving off that the engine will absolutely scream.
 
I may be in the minority here when I say this, but I believe it is best that vehicles behave predicably and within reasonable expectations of performance, without needing a nerd behind the wheel who knows how it all works.

Another way to get the car to have 1 bar is to accelerate aggressively, put the car in neutral, come to a stop, and repeat many times.

I might also be in the minority in saying that we may need to discourage nerds from operating vehicles in peculiar ways, in order to give the vehicles an opportunity to operate as designed.

Why would anyone do what you’ve suggested?

As Groucho Marx once said, “Trying to make something foolproof is impossible, because fools are so ingenious”.
 
from the point of charge sustain mode 2 bars is ideal.

Charge sustain mode will attempt to maintain the SoC,

Can you explain how 2 bars is ideal “from the point of charge sustain mode”? FWIW: Charge Sustain Mode is commonly referred to as HV Mode on this forum. Likewise, Charge Deplete Mode is typically referred to as EV Mode.

It seems that 2 bars would only be ideal in HV Mode, if HV Mode were to be engaged when the battery was at 2 bars. In a twist of events, the car does that by default and a set point of 2 bars is established. Many owners consider allowing that to happen to be a precursor to a less than desirable driving experience.

In my experience, a SOC at or near the set point would be ideal in HV Mode and a set point above 2 bars would be the preferred option.

I’m all ears.
 
I might also be in the minority in saying that we may need to discourage nerds from operating vehicles in peculiar ways, in order to give the vehicles an opportunity to operate as designed.

Why would anyone do what you’ve suggested?

As Groucho Marx once said, “Trying to make something foolproof is impossible, because fools are so ingenious”.
Because it's interesting? Because it lets you understand how the vehicle works better? Because you can? And you are operating the vehicle as designed. Not operating the vehicle as designed would be like running out of gas, slamming into curbs.
 
Another way to get the car to have 1 bar is to accelerate aggressively, put the car in neutral, come to a stop, and repeat many times.

And you are operating the vehicle as designed.

Show me, where in the Owners Manual, your maneuver is recommended by Honda.

I’ve deleted the manual since we sold the car, but seem to recall a specific warning about not putting the car in neutral when driving.
 
Can you explain how 2 bars is ideal “from the point of charge sustain mode”? FWIW: Charge Sustain Mode is commonly referred to as HV Mode on this forum. Likewise, Charge Deplete Mode is typically referred to as EV Mode.

It seems that 2 bars would only be ideal in HV Mode, if HV Mode were to be engaged when the battery was at 2 bars. In a twist of events, the car does that by default and a set point of 2 bars is established. Many owners consider allowing that to happen to be a precursor to a less than desirable driving experience.

In my experience, a SOC at or near the set point would be ideal in HV Mode and a set point above 2 bars would be the preferred option.

I’m all ears.
HV mode is a term that can be misinterpreted. When you press the HV button you are entering what is called SOC maintenance mode (basically a modified version of charge sustain mode, but they are not the same thing), when you run the battery to 2 bars it enters Charge Sustain mode. By ideal I mean that the normal range of charge that the PCM attempts to maintain is 7-13% or so. If the SOC falls to below 7% it will start deviating from optimal control in order to compensate for the battery getting low.
 
Show me, where in the Owners Manual, your maneuver is recommended by Honda.

I’ve deleted the manual since we sold the car, but seem to recall a specific warning about not putting the car in neutral when driving.
Honda also doesn't specify how to use the steering wheel, accelerator, or brake pedal. Putting the car in neutral isn't ideal from the point of view that you loose the ability to accelerate, and you loose all regen. It isn't something I would recommend you do in a populated area, but it won't cause any harm to the vehicle.
 
Honda also doesn't specify how to use the steering wheel, accelerator, or brake pedal.

Typically manufacturers specify what not to do. The assumption is that you’ve completed a driver’s training course and are licensed to operate a motor vehicle.

Putting the car in neutral isn't ideal from the point of view that you loose the ability to accelerate, and you loose all regen. It isn't something I would recommend you do in a populated area, but it won't cause any harm to the vehicle.

Is causing harm to the vehicle a necessary condition in order to meet your definition of operating a vehicle in a manner for which it was not designed?

The car was designed to recapture kinetic energy while slowing. Did you know that applying the brake pedal recaptures energy? By shifting the car to neutral and coasting to a stop, you are intentionally operating the vehicle in a way it was not designed to operate. Does that “harm” the car? Perhaps not physically like jumping curbs or slamming into a wall, but it forcibly depletes the battery, which can then cause the vehicle to be unable to operate in one of its designed modes.

You are, in fact, operating the vehicle outside of the way it was designed to be operated.
 
Typically manufacturers specify what not to do. The assumption is that you’ve completed a driver’s training course and are licensed to operate a motor vehicle.



Is causing harm to the vehicle a necessary condition in order to meet your definition of operating a vehicle in a manner for which it was not designed?

The car was designed to recapture kinetic energy while slowing. Did you know that applying the brake pedal recaptures energy? By shifting the car to neutral and coasting to a stop, you are intentionally operating the vehicle in a way it was not designed to operate. Does that “harm” the car? Perhaps not physically like jumping curbs or slamming into a wall, but it forcibly depletes the battery, which can then cause the vehicle to be unable to operate in one of its designed modes.

You are, in fact, operating the vehicle outside of the way it was designed to be operated.
My apologies for assuming that you wanted answers and proof to questions. I was simply stating a way that you could try putting the car in a very low state of charge to test if engine drive would engage.
 
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