ICE runs after going down a hill at the beginning of my drive.

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Maybe the simple solution is to charge to 90%. That way Bob can recapture the energy in regen going downhill and avoid having the ICE come on at the same time. Also, not charging fully will prolong battery longevity. Seems like a win-win.
 
I haven't looked into this in depth since it doesn't apply to our (my) geography, but my wife's Bolt has a feature called location based charging.
If you have a regular charging location at home or work, for example, that is at the top of a hill, you can set that location only to end charging with battery capacity left over.
In other words, charge to 80% at that location only.
Seems to be designed to avoid starting a trip at 100% charge when a long regen is expected immediately thereafter.
If this is in any way related to the scenario with the OP, The odd drive-train logic might be expected behavior.
Not sure why the engine would start, but if DT logic doesn't expect/like regen when at 100% charge we may see otherwise unexplained behavior.
If the issue does not present when leaving (down hill) after 80% or 90% charge, we can assume the events are related.
 
I’ve taken to avoiding using regen via paddles or going really easy on the brakes until I get below 50 miles of range to reduce risk of ICE coming on. Working so far...
 
Yesterday: Did not use paddles. Went easy on brakes. ICE came on 4 times in less than 3 miles. But not today!!!!!
 
Well, this finally happened to me after 4 months and almost 1900 miles. Fully charged at work, drove my normal route towards home (which is a slight downhill - I use about 3 miles EV range to go 5 miles) and the engine came on while I pulled the regen paddle while in sport mode about half a mile from work. I wouldn't have noticed except the power meter went white.

I've realized that the only time I notice when the engine is off is when it shudders and turns off. What was interesting was that the power meter stayed in the white for the remainder of my drive home, even if the "EV" letters came on and the energy display showed that I was only using battery power for propulsion.
 
This is happening too many times to be a fluke.
I just can't imagine why the engine would fire up.
I could understand the generator spinning the engine with fuel off to dump charge.
 
Mine has done this both days in a row . Not sure if it's a bug in the Software but I drove for 20 min and it stayed white indicating it was on. I felt the engine at the beginning but by the end of my commute it seemed as if the ICE was off even though the dash showed white . Lost 15 percent of battery so I did go most EV
 
Not sure if this is the case here, but my friend who has a Volt told me that his ICE runs once a week for about 10 mins when he drives in EV mode for the rest of the days of the week. Gas engine needs to run to stay alive according to him.
 
Volt manual says othewise.
Screen Shot 2018-07-26 at 6.47.55 PM.webp
 
Atkinson said:
This is happening too many times to be a fluke.
I just can't imagine why the engine would fire up.
I could understand the generator spinning the engine with fuel off to dump charge.
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I believe that the 4,000 lb the Clarity PHEV needs to offer more powerful pseudo engine braking (including paddle-initiated regen) than could be provided by the lighter Accord Hybrid's method of using the starter motor/generator to spin the unfueled engine to burn off excess regen energy when the battery is fully charged.

If I'm wrong I would welcome the actual explanation, but my theory is that the Clarity PHEV uses the starter motor/generator in reverse, to slow the running engine and burn off excess energy faster than the Accord Hybrid can. The curious downside is that the super-efficient Clarity PHEV--against character--uses fuel to dispose of excess electricity generated during pseudo engine braking.
 
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insightman said:
I believe that the 4,000 lb the Clarity PHEV needs to offer more powerful pseudo engine braking (including paddle-initiated regen) than could be provided by the lighter Accord Hybrid's method of using the starter motor/generator to spin the unfueled engine to burn off excess regen energy when the battery is fully charged.

If I'm wrong I would welcome the actual explanation, but my theory is that the Clarity PHEV uses the starter motor/generator in reverse, to slow the running engine and burn off excess energy faster than the Accord Hybrid can. The curious downside is that the super-efficient Clarity PHEV--against character--uses fuel to dispose of excess electricity generated during pseudo engine braking.
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Why do you guys assume when the engine start it has to consume fuel? The car can simply turn on the starter and let the engine crank without injecting any fuel to it to burn off excess energy
 
I assume so because the hour meter I have wired to a coil over plug tells me the spark plugs were energized and one time when it happened, I pulled over, popped the hood, and heard the engine running. Also I saw the ICE icon illuminate in the center display and my HV range decreased by 1 mile.

However, there is no way to tell exactly what caused the ICE to turn on. Since multiple people have reported it occurs immediately after a full charge with downhill or hard braking we are speculating that it is because the BMS is protecting the battery from over charging due to regen added charge. The fact that regen is limited after a full charge supports this hypothesis.
 
Except that the behavior is inconsistent as I have reported. Sometimes ICE comes on sometimes it doesn't.with identical full charge and driving conditions. Honda won't admit it, but there must be some bad programming. I can attest to that fact since I have written many apps. And guess what? They had bugs. That is why there are beta testers. I am afraid that is what we are.
 
bobcubsfan said:
Then why does the HV mileage go down? That should only happen if fuel is being burned.
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Good point, but given the previous HV miles bug I wouldn't totally trust that piece of code either, also the HV mileage include the EV mileage too so maybe the code consider that as a waste hence lower the HV mileage when it should be adding to the EV mileage normally.

Unfortunately it is almost impossible for us to do the good old gas fill/mileage calculation to know if it (or how much) burn fuel.
Like you guys are saying, it is counter intuitive that we have to burn fuel to waste the excessive energy. My experience taught me that most engineers are not idiots, so if something doesn't make sense probably because we don't know what is actually happening or there is a really really good reason behind it that force them to do something that makes no sense to make it work. Of course there are engineers that are actually idiot but I sure hope they don't last long in automotive industry.....
 
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