ICE in EV Mode ... Again

such a waste of electrons, could be put to better use, lol

 

and on top of that after regen. ICE wastes more gas b/c of emissions reg's

 

If the electric motor is being used to spin the ICE why does it need to use gas? Or when you say "spin" do you mean it acts as a starter motor and then the ICE takes over? That doesn't seem like it would dissipate much charge.

 

when you're coasting downhill in a non hybrid not much gas is burned, the pistons are just compressing air

 

So that would suggest that when the ICE goes on in that circumstance you would be using very little gas. Certainly less than in normal HV mode.

 

right, but why does the prius need to use any gas at all? once regen is finished you'd think ICE would simply shut off and use EV, but NOOOOOO! emissions laws trump everything

 

Here we go, as promised. There is a clear relationship between the battery state of charge and the amount of power it is allowed to charge (from regen).

Since my battery is near room temp, it remains at 50.3 hp. My theory is that, if the battery temp drops, so will it's discharging power.

 

dono, just making things up as I go

 

I think that since it is spinning, it wants to get it "warmed up" properly.

It may be that the entire process is controlled by a state machine that was designed long ago for the original Prius. It is known and works so they didn't change it. And maybe it protects against some worse case, long term issues with engine wear. So when the ICE is going to be spinning they only want it to do so cold a short time, then make sure it is warm with gasoline burning, then OK to spin warm with no gas. Remember all this is for the (we think) rare case of coasting/braking going downhill with a full battery with no place to store the electrical braking energy.

Maybe an edge case in the design that they weren't too worried about optimizing. I mean, you already have a full battery and are getting a free ride downhill.

Mike

 

Yes. MG1 acts as both generator and starter. It consumes electricity when acting as a starter motor.

We don't know the reason why gas has to burn whenever ICE is spinning. There must be a reason for it. Perhaps due to emission law as I recall as well. Catalytic convert has to warm up and complete the warm up cycle.

 

good point, thanks Mike

 

Great. Do you have Torque or SGII to pull the battery temp?

 

r

This makes sense. I have noticed that when the ICE goes on in EV mode, say due to a burst of acceleration, it stays on even when you slow down. A requirement to reach a certain temp whenever it starts would explain that. Also, stopping the car, turning it off and restarting seems to abort the ICE program.

 

I really dont think battery temp has anything to do with this phenomena. A few days ago, I left the house with a 60F or so battery (45F outside temp?). When I left the house the 2nd time (40 minutes later), my battery pack temps were around 65F. In both cases, I finished charging within 10-15 minutes of leaving the house (actually 2nd trip out, the battery finishes charging within a few minutes.. the miracle of L2 charging).

The idea of the max regen sounds more plausible to me. Although for the tables I posted from 12/17, in both cases, there wasnt much regen going on and I was well below the usual 83.9 or 84% threshold I've experienced in the past.

I have also been thinking it may have something to do with MG1 or MG2 temperature and speed. My thinking is there is some kind of "relationship" where if the MGx temp is X, then anything over Y MPH will trigger the ICE. I need to log more though to know if I'm even in the ballpark.

 

Yup, a new warmup strategy was developed to meet SULEV emission requirement, with the ability to provide sudden high power loads.

 

well, i think the point is that the battery temp determines how much regen it can accept, AS WELL AS the current SOC. make sense?

 

I understand the thinking.. I'm just saying, what I've experienced and logged with Torque would seem to indicate that is not the reason causing the ICE to start in "lower" temperatures. I guess I should say "not the reason causing MY ICE to start".

EDIT:

I was just looking at my logs from 12/17 and in both cases, it LOOKS like the ICE started when MG1/MG2 RPMs reached ~5000RPM.

During my 7:18AM trip, my battery temps were 60.35F, 60.55F, and 61.47F. I was going 40.39MPH when the ICE fired up. MG1/MG2 RPMs were at -4814/4864 RPM.

During my 8:24AM trip, my battery temps were 64.97F, 66.06F, and 66.06F. I was going 44.74MPH when the ICE fired up. MG1/MG2 RPMs were -5187/5279 RPM.

This morning I thought speed has something to do with it. The ICE started at 40MPH (on the dash - I wasnt logging today). But maybe it has something to do with MG1/MG2.. I'm thinking if the temp is too low (or below a certain temp), then it can only spin so fast when its cold-cold.

I'll add MG1/MG2 temps and the HV Control to my logging.. as long as my ancient G1 doesnt crash on me, I should have some more conclusive data tomorrow.