Cold weather cruise control and unexpected engine ON

Okay, John, listen to this.

The other day, I left the car outside in 56°F weather in intermittent sun. When I got in, the interior was about 70°F. I was at 100% charge and accelerated to leave work. When I got to the end of the driveway, I accelerated to highway speed, descended a hill and right at the bottom of the hill as the hill was transitioning from down to up, I set the cruise control. The battery was at 96% by then. The engine started *instantly* while I was watching. I felt it also. I've done the same thing hundreds of times without setting the cruise and the engine never started. I've done is more than a dozen times in the same place with the battery below 95% and the engine never started.

That is not a cold condition. It was not regenerating or motoring when I set it. It has never started outside the 96%-99% window and it has never started without cruise, in the exact same place. I've been in that same place after a 15°F all-day cold soak and a 90°F in-the-sun hot soak and the engine never started, all with battery below 95% or at the same level and without setting cruise.

 

No... because you refuse to step back to look at the bigger picture. You are forcing an old paradigm to address a new problem. Continuous improvement means trying new things. If you find something can work better, you suggest the improvement. Absolutely insisting something is wrong, rather than acknowledging process, is a recipe for failure.

Notice the forest, not just the tree directly in front of you. Don't get so hung up on detail that you forget about goals. Big picture is vital. This is why Toyota takes the phased approach, upgrading when the situation best fits, rather than trying to deliver it all at once.

 

Read what I wrote. This ICE activation makes absolutely no sense. It doesn't protect for temperature, regeneration, over-charge, high-throttle, or anything else. At the very same location I can go from max regeneration to floored without activating the ICE but activating cruise while coasting does activate the ICE. Explain that.

 

I already did.

Refusing to accept the upgrade process is your loss.

 

No, you did not. You said:

None of these situations apply to this particular ICE engagement, which is a clear bug.

 

The upgrade process involves improving which also involves resolving any issues.

 

In a software based system if the problem can be "fixed" by restart/reboot/refresh it's a bug. Since this ICE starting issue can be worked around by doing just that with an on off on sequence and then having full use of EV and DRCC, protecting the battery is not really applicable. So far the problem seems to me to be a data communication fault while in plugin charge configuration. (Lengthy discussion of CAN transceivers and issues with their sleep, standby, and pseudo off modes anyone?).

Have you guys tried substituting acc for the initial on in the on off on routine? While plugged in and unplugged? Acc wakes up different subsystems. Maybe one that is "sleeping" on the job.

How about regening to 96%+ followed by the needed cold soak to separate the act of charging from battery state? Hard to do in the moleskin mountains of AL and Mi I know just a thought.

Hard to sell someone on a plugin/EV with advanced($$) options like DRCC or Entune if they don't work together well or at all.

 

What problem?

There is a scenario being overlooked still... hence the request to step back to consider the bigger picture.

This happens every Fall, quite predictable & routine. There's a cold, hard rain falling. You want to both warm yourself and clear the windows. With full manual control, you make due with the heat-pump just blowing warm air. Switching to semi-auto (cruise with radar), you hand over some control to the system. It chooses to use the heat-pump for defogging the window, which requires cooled air. That means the heat must come from the engine via the heater-core with coolant.

In other words, the posts here are far too limited in scope. The vague nature and generalizations aren't taking all scenarios into account.

Put another way, the engine coming on is the fix.

 

So how does this apply to my scenario, 56°F, 70°F inside the car, HVAC turned off.

 

No, it can never be truly reproducible because environmental conditions are never identical. So it has to be a statistically significant problem.

 

At best this discussion involves a way that Toyota might be able to further optimize the behavior of the vehicle.

It is clearly not a safety problem and I've seen no argument for why Toyota would regard this as something that is broken or must be addressed in the currently "working" vehicles. It might get as far as qualifying as unexpected operation and maybe it could get recorded somewhere as an opportunity for a future improvement but everything here indicates this is 100% benign.

I applaud @bwilson4web for taking the time to capture the scenario and report it to Toyota. Hopefully they too appreciate the input and look at it in a future version of software but in all my years of product development I can't imagine a scenario where it would make sense to change something like this in a fully functional product that has undergone extensive testing and qualification. The opportunity for unintended consequences hugely outweighs any possible benefit and any product manager who suggested modifying existing vehicles would likely be fired long before it reached the second level of decision making.

Maybe if you see this improvement in a 2019 or 2020 prime, @bwilson4web can take comfort that his effort made a difference.

 

I had an unexpected engine on this morning, but it shouldn't have been as it was 6°F. However, this led me to do a test.

I let the engine run through warmup with the heat on very high (72°F, no Eco, no S-Flow). This warmed the car up very quickly to a high temperature. Then I turned on the seat heater and the steering wheel heater and pressed "Off" on the HVAC controls. The engine stopped *instantly*, and never came on again.

 

More information.

Yesterday, car sat in the sun all day, full charge, but had to drive around the site a bit before I left. Got to the spot at the bottom of the hill at 91%. Hit cruise and engine started instantly.

So today, same temp, sun all day again, 100% charge, 97% at the bottom of the hill but I didn't set cruise until I was climbing the next hill, which is about 5 seconds after the other ones. Cruise didn't cause the ICE to start.

Maybe it only happens at near-coast?