The elusive gear icon

[MNSteve]

Computers are supposed to be deterministic. I have worked with them for decades, and I know that sometimes there are variables that they're considering that we humans are not. I am trying to figure out what they are in this case . . .

Today I took at short trip, 30 minutes each way. Most of it was on I35, which in this area is rolling hills but none of them very long or very steep. On the outbound leg, the gear icon appeared and disappeared consistent with my previous experience. It was pretty elusive, going away at the slightest hint of a hill or an attempt to accelerate. The controller even shut down the ICE and turned on the EV indicator on the panel briefly a couple of times.

On the way home, the gear icon pretty much came and stayed. The behavior was dramatically different. I'd say that on the Interstate portion of the trip on the outbound leg the gear icon was there 10% of the time and on the return it was 90%.

HV mode. Same road. Same conditions - no rain, no wind. Temperature not more than 5F° different; climate control in the car the same. Cruise control set to the same speed. Slightly less charge in the battery on the way home, but not much; EV range was reading about 20 on the trip home, started at about 29 on the trip out. Other than going north one way and south the other (and remember, no wind) the trip couldn't have been any more similar, but the behavior of the algorithm that decides the power flows was much different.

The car drove fine at all times. If it hadn't been for the panel display and an occasional whine of the engine, I would not have been aware of any difference. Maybe there are things we just shouldn't know.

 

[jdonalds]

My guess is a slight elevation increase on your outbound leg, and of course elevation decrease in the return trip. It doesn't take much.

 

[MNSteve]

My guess is a slight elevation increase on your outbound leg, and of course elevation decrease in the return trip. It doesn't take much.

I took someone else's suggestion in a post I just read, and asked Google. I am not sure I know how to interpret this, but it looks like the highest point on the trip is 1316 and the lowest is 1152. I see your point. That might be just enough to explain what I saw.

 

[Clarity_Newbie]

I took someone else's suggestion in a post I just read, and asked Google. I am not sure I know how to interpret this, but it looks like the highest point on the trip is 1316 and the lowest is 1152. I see your point. That might be just enough to explain what I saw.
View attachment 3139

MNSteve

Your observations are identical to mine reference noticing less gear engagement during elevation gain.

It seems reverse logic to me but I'm going to roll with it. lol

Good luck!

 

[jdonalds]

It's all about the Atkinson Cycle engine. That engine design is superb at maintaining the constant speed of the car but it needs help accelerating. We don't find ICE cars with only an Atkinson Cycle engine because it is a pig off the line. So that design is used in hybrids where the battery and electric motor can provide the torque for acceleration.

If the car is going uphill that will demand a bit more power and Honda gets the power from the battery and electric motor, not from the engine. So the engine is easily disconnected and propulsion is turned back over to electric components.

On the downhill slope the engine isn't being asked to work hard so it can stay engaged longer.

 

[MNSteve]

It's all about the Atkinson Cycle engine.

I'm just amazed that the difference was so dramatic. I need to break out the stopwatch and record the amount of time the gear icon shows. I suppose that would vault me to a new level of geekness even in this august group.

 

[David Towle]

I'm just amazed that the difference was so dramatic. I need to break out the stopwatch and record the amount of time the gear icon shows. I suppose that would vault me to a new level of geekness even in this august group.

I am noticing that I can get the gear icon to stay on much more of the time if I don't use the cruise control in hilly areas. For some reason, at least on mine, when going downhill it gradually reduces speed, then when you start going up the next hill it slams the throttle wide open to get back to the right speed. Does this even worse if you leave the car in Econ. This not only affects the gear icon time, but also the gas mileage both from slamming the throttle open and not running in gear mode. I've never owned a car with a cruise control anywhere near this bad. Does yours exhibit the same cruise control behavior? When set at 72, mine typically drops as low as 68-69 on downhills, and overspeeds as high as 74. My previous car was always +/- 1 mph.

 

[MNSteve]

Does yours exhibit the same cruise control behavior?

The cruise control on the Clarity is not as good as the one on our CRV, but mine is not misbehaving nearly as much as you describe. The big difference for me is that the Clarity will actively apply brakes (regen, I hope) to slow down the car if the speed is higher than set. In the CRV, if I increase my speed to pass another vehicle, pull back into the right lane, and lift my foot off the accelerator, the car will coast down to the speed I had set and then add gas as necessary to maintain that speed. If I do this with the Clarity, when I lift my foot off the accelerator, I see a significant braking to slow the car back to the set speed. I can see how this might be useful while descending mountains, but I don't have any.

 

[jdonalds]

The cruise control on the Clarity is not as good as the one on our CRV, but mine is not misbehaving nearly as much as you describe. The big difference for me is that the Clarity will actively apply brakes (regen, I hope) to slow down the car if the speed is higher than set. In the CRV, if I increase my speed to pass another vehicle, pull back into the right lane, and lift my foot off the accelerator, the car will coast down to the speed I had set and then add gas as necessary to maintain that speed. If I do this with the Clarity, when I lift my foot off the accelerator, I see a significant braking to slow the car back to the set speed. I can see how this might be useful while descending mountains, but I don't have any.

To me that behavior is positive. It isn't the best for fuel economy, but its the only car I've had that will maintain the set speed when going downhill as well as uphill. I use it every day to descent the 1/2 mile hill near our house. I just set it at the posted speed limit of 40 and it manages it for me. I don't have to use the paddles or brakes to maintain that speed.

 

[David Towle]

To me that behavior is positive. It isn't the best for fuel economy, but its the only car I've had that will maintain the set speed when going downhill as well as uphill. I use it every day to descent the 1/2 mile hill near our house. I just set it at the posted speed limit of 40 and it manages it for me. I don't have to use the paddles or brakes to maintain that speed.

Does yours overcompensate and go well below the set speed like mine?

 

[jdonalds]

It's usually one mile underthe set speed.

 

[Richard_arch74]

One other thing: I had the cabin heated to 70°F.

 

[MNSteve]

One other thing: I had the cabin heated to 70°F.

Ummm There seems to be something missing here. I got an email notification that you made a long post which started "@MNSteve, not to threaten your geekness but" and it doesn't seem to be here.

 

[Richard_arch74]

Ummm There seems to be something missing here. I got an email notification that you made a long post which started "@MNSteve, not to threaten your geekness but" and it doesn't seem to be here.

Yeah, I had a senior moment. I tried to edit my original post, which was a response to one of your posts, and somehow the edit didn't include the original post. I'll have to recreate it. Stay posted.

Sent from my SM-G955U using Inside EVs mobile app

 

[MNSteve]

Yeah, I had a senior moment. I tried to edit my original post, which was a response to one of your posts, and somehow the edit didn't include the original post. I'll have to recreate it. Stay posted.

I have it in the email. You said:

@MNSteve, not to threaten your geekness but . . . I had a chance yesterday evening to drive in HV mode, non econ, light traffic, on cruise control, driving 64mph, flat terrain, little wind, 34°F, partly cloudy, 29 miles of EV range, there's 106 miles to Chicago, I've got a full tank of gas, half a pack of cigarettes, it's dark out, and I'm wearing sunglasses: I got to a sweet spot where the gear icon was always on, green flow to the battery, for many miles and the EV range was increasing about .1m for every .5 miles of travel. It was almost like being in HV charge mode but I wasn't (could hardly hear the engine).
Then some knucklehead pulled in front of me and broke the trance.

[MNSteve's words now] And that's kind of what happened to me on the way back when I was getting the gear icon consistently.

 

[petteyg359]

It's usually one mile underthe set speed.

I've noticed this, and I suspect it is a rounding issue with the display. I'd guess it just truncates decimals, so 39.8 mph shows as 39 instead of 40.

 

[Viking79]

Put the car in Sport mode if using AC. To me it is more more pleasant and consistent holding speed. In Econ I find the speed varies too much and it is much too slow to recover lost speed. Maybe more efficient of course, but I have never noticed an issue with efficiency except maybe in very cold weather or when experimenting with HV Charge (got 33 mpg for a drive, after driving off added electricity).

The difference is interesting in direct drive operation. What was the ambient temperature and speed? I have never tried to characterize how much it is used or not. Remember it is direct drive, and similar to an overdrive gear in a car, so probably best at certain speeds. Adjusting your speed might make it use it more or less. On the uphill you could try a faster (or slower) speed and see if it engages more or less.

 

[MPower]

Tried to keep an eye out for the gear icon on my 1500 mile trip to my daughter's for Christmas vacation. Could not do it consistently because needed Android Auto google maps on my center display pad so I didn't end up in Buffalo and Chicago. But on stretches where I either knew the way or the directions said, "Drive on I70 for 195 miles," I swithched the view to the Honda info and kept a lookout for the tiny gear.

On the first day out, I was traveling on a number of ordinary roads, and the gear appeared for a relatively long time at around 47-55 mph. Aha, I thought.

However, later on I70, which was pretty flat, it would appear for quite long spells when I was cruising along on ACC at 67-68 mph, sometimes the battery would be receiving and sometimes discharging. I think the gear would disappear when I would hit a slight upgrade.

What with keeping track of my podcasts, audiobooks, and being constantly told that steering was required (when it actually wasn't because the road was totally straight), I could not follow the comings and goings of the gear enough to satisfy the high data standards of this forum, but these are my observations.

 

[MNSteve]

The difference is interesting in direct drive operation. What was the ambient temperature and speed?

Temperature was around 35°F. Cruise was set at 69 mph. And yes, ECON mode.

 

[Viking79]

Temperature was around 35°F. Cruise was set at 69 mph. And yes, ECON mode.

It would also be interesting to see what your MPG was for those (just via trip, even if computer is optimistic). Reset one of the trips when you put it in HV and it will start calculating MPG for you (I always use trip A, I think both might have an MPG value, but not sure). My hunch is it was the elevation though, even if not a lot. Really hard to say.