Delay in switching back to EV

My theory is that, when the outside temp is very cold, the PHV battery pack is cold as well. Perhaps you parked it outside overnight? Unless you park in the heated garage, your pack will be close to the outside temp as well.

When the pack temp is low, it can make limited power. It won't make 38 kW like in normal condition. If you have your accelerator pressed at say 20 kW and the pack can't provide that much power, it won't go into EV mode.

That's my theory anyway. With custom PIDs in Torque app, you can see the discharge and charge power allowed by the computer. Those numbers change depending on the pack temp as well as the battery SOC.

 

This happens occasional to me as well at the end of my 53 mile commute so I know the engine is good and warm.

For me, it doesn't last for miles though. It lasts on the order of 10's of seconds. It's never taken more than a minute for the EV icon outline to finally fill in and the ICE turn off. The only pattern I've noticed is that it usually happens when just prior to pressing EV, I had pressed hard on the pedal so that the HSI was near or in PWR.


iPhone ?

 

Uropip,

I also do highway driving and have noticed this same situation. Your distance before EV engagement is much greater than mine. Are you going downhill and regenerating?

I slowdown to 55 and then accelerate slightly and it goes into EV.

 

Do you park outside before this commute? What are temps like?

I haven't really had any issues like those mentioned above. I will even kick it into EV going down hills using cruise control sometimes with no issue.

 

i notice that potorap and mmmodem are in warmer climes.

 

Possibly something in the emissions system needed to be at a certain point.

 

I also see the delay occasionally- more frequently in the winter, but it did happen once during the summer too.
I think it's related to battery protection.

 

I think I understand your symptoms. My strategy is to wait while slowing down at freeway off-ramps etc. until the HV mode's "full green car" icon shows on the display indicating that algorithms have shut off the ICE on their own before I manually switch to EV mode. Once the PiP is warm, that "full green car" icon takes from 1 to at most 8 seconds to appear, depending on the rate of slowing down.

 

I about guarantee is has to do with battery temp. Using the battery doesn't heat it up near as much as what people think. That combined with you are obviously in HV for the highway portion, which wouldn't do anything to the temp of the battery. The battery is simply cold.

 

Cold battery will definitely prevent EV mode. It must be drawn from a little bit to generate some internal warmth.

A simple solution for that is to simply switch to EV-BOOST shortly before you want EV. That will be enough to provide the needed heating. It also allows you to capture more from regen as you exit the highway.

 

It could be that it is trying to return the borrowed charge into the battery before shutting the engine down and go into EV mode. HV mode is charge sustain so, the computer may be trying to get the state of charge back to the level it started at.

 

I've noticed that mine is sluggish to drop back to EV after driving over 65 until I let off on the throttle.

 

Get an aftermarket gauge and watch what happens. It's cutting fuel and allowing the engine to spin without consumption, waiting to see what you want from the system next.

Letting up on the throttle instructs it to shut off the engine right away. It would eventually do that later. But there isn't much to gain since gas isn't being used then anyway.

 

Is this spinning with engine compression or without? Sometimes the system uses engine compression as a way to dissipate energy as an alternative to applying the friction brakes, when the battery is full and cannot take any more regeneration. Other times the engine is spun without compression (essentially free-wheeling) to satisfy the speed differential constraints in the power split device. (The Hybrid Synergy Drive is a real engineering marvel.)