Sudden hard acceleration starts ICE, but it won't turn off - why?

Just a thought, did you break hard before the ICE came on? Could clarity be turning on engine breaking when there is too much regen current?

 

The spring has finally come to Vermont and suddenly the ICE is coming on when I would not expect it in situations that did not cause it to come on all winter -- very counter intuitive.

 

I was braking since it was kind of stop and go but nothing I would call hard.

 

I personally know that the C-Max Energi does. I also know these PHEV's also have pressurized fuel systems: Prius Plug-in and Prius Prime. I'd wager to bet that every PHEV has a pressurized system regardless if they have a FMM.

 

@Tim66, and others with ICE running often any updates? Try filling the tank with fresh gas. The Volts factor in average age of the fuel so when new gas is mixed in it changes the burn old fuel clock. Maybe the Clarity will too.

 

My recent experience with ICE coming on was during changes in the weather. I am thinking the battery was charged at one temperature, and the car was running through a different temperature, so the battery temperature was changing. This change in battery temperature (colder?) may have changed the 'effective' SOC, and the ICE sensed an overcharge situation...

 

Nothing changed. I haven't gotten into ICE "mode" for a while because I'm careful about going past the detent or pushing the pedal too fast. Yesterday after driving for about 10 miles in EV mode, as a test, I accelerated quickly (flat surface, this is central Ohio afterall) and the ICE came on. 20 minutes later, without pushing any buttons, it was still on. I miss my Volt. My solution to this problem is to just not accelerate quickly unless absolutely needed for safety reasons. Which is a good idea no matter what car you are driving. The stuck HV range display has not returned since the last dealer visit.

Tim

 

Tim66: Did the EV range stay constant during the 20 minutes that the ICE ran? Did it drop a little first, then stay constant?

 

Bill, to be perfectly honest with you, I did not take notice of the EV range while in ICE mode. In the past I have switched the Information Display to show the battery and saw that ICE was supplying power to the battery when I was in one of those unwanted, extended ICE modes after going past the detent.

Tim

 

Tim66: No problem. That is a really frustrating experience. I have my theories on how the Clarity works, and they mostly focus on SOC.

Thanks!

 

Do you believe the ICE runs longer at certain levels of the battery's SoC? I've had the ICE run short (as expected) and long (perplexingly) in both high and low states of battery SoC.

 

Based on @KClark posts, I might try taking the negative connection to the battery off for a minute or so and then let the car reboot. This seems to have given a couple of Claritys the nudge they have needed to get back to better behavior when they have suddenly changed. I think all it takes is a 10mm wrench and some patience on the reboot.

 

I believe disconnecting the positive terminal is much safer.

 

I will defer to your better judgement here. I wouldn't have known there was a preference.

 

Stop. I was wrong. It's safer to disconnect the negative terminal as you originally planned. I thought I'd read other members rebooting by disconnecting the positive terminal, but googling battery removal/installation procedures always produces negative terminal disconnect first/connect last results.

 

The logic is if you are working with the positive terminal first with metal tools you can accidentally make contact with a part of the car body or engine which is grounded/negative and cause a short. If you disconnect the negative first nothing happens if you accidentally contact the body/engine. Once the negative is disconnected there is no longer a danger of a short circuit while working with the positive.

 

Generally, the ICE just runs to engine temperature.

But, it does appear ICE also tries to reach the 'target' SOC. The SOC may drop significantly during warmup, whether warmup is caused by switching to HV or by forced ICE operation. When the SOC drops below target, it seems the ICE 'wants' to get back to target before shutting down.

If the drive load is significant, there is not surplus power to restore charge to target. Most of my anomaly ICE runs have kept the ICE at 1500 rpm (warmup speed), so the surplus power is restricted.

If the SOC is over 85%, the ICE takes longer to restore target, because the battery does not seem to accept charge as well.

Target charge is related to the SOC when the ICE begins operation, or switching to HV mode

Most of my driving has been in sub-freezing temperatures. I am just getting some experience with warmer weather. One of the things I am noticing is that it takes longer to get the SOC below the 57% threshold - EV range is significantly higher.

The weather in upstate NY has wide temperature variations, and this seems to be affecting ICE random starts.

 

Since it never shuts off I can't answer that question. Bur remember, I'm talking about my starting of the ICE by going past the detent in EV mode, not it coming on unexpectedly during normal driving.

Tim

 

Had a similar issue yesterday. I have run my Clarity in ECO mode pretty much since I bought it, and over the last 5 months, have a pretty good idea of what to expect when I drive it. Yesterday, I had to floor it on a highway merge, which kicked in the ICE. So far so good. However, the car would not come out of hybrid-mode. In other words, it began to act exactly as if my battery had been depleted and would run in EV and low speeds / low acceleration, but kept the ICE on at highway speeds. I had about 80% battery at the time. My commute is about a half-hour on a flat road (no hills or anything). This behavior cleared after I got to work, shut down and charged it at my office. Its operating normally now. Sounds like a software bug to me.

 

I continue to see the ICE kick in almost every day on my standard commute. I noticed something this morning as I got on the freeway with almost 100% battery. I accelerated out of the onramp and had to pass a slower car in the slow lane. As I was accelerating the ICE came on. I wasn't watching the power gauge carefully, it's a little hard to do that and drive safely so I don't know if the power gauge exceeded the detent, but this wasn't a lead footed mash on the accelerator pedal, this was a steady application of power that I do every day and that I had done repeatedly in the first 4 months of ownership when I never saw the ICE engage. I'm going to try and watch this more carefully and experiment with changing to Econ mode. But again, I didn't use Econ for 4 months, I drive the same route with essentially the same conditions every day, I'm a very conservative driver when it comes to sudden acceleration after driving an F150 for 15 years and trying to milk a few more mpg out of it. Nothing on the driver's side of the equation has changed but something very definitely has changed on the vehicle side.