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Time to get into the technique Q & A again. This time I'm curious about glide entry. For the last 3 month's I've been perfecting a Pulse-to-EV-to-N-Glide transition, but after Hybrid Fest and the deep dive on how the ICE-on, ICE-off transitions happen, I began to question my technique.

To recap, from what I recall hearing, when the ECU tells the engine to cycle off (from DICE-on to DICE-off) a few distinct things happen. The injectors get cut, the engine stalls, but the EV (if I recall), park the CAM or cylinders in the exact position to allow an easy light when it re-ignites the the ICE. As I under stood, this pr event's the few cycles of the CAM to get the ignition timing synced up. If you know the cylinder's are at an exact position, you know as soon as you inject, and spark, your up and running.

So, here's my question. How long does it take for the cylinder's to park?

Now when I said I had perfected the DICE-on to NICE-off transition, I mean really perfected! I've got it down to about 200ms and I usually get one of the classic S2 shudders in the seat of my pants as the ICE stalls. The way I do it is to use the Factory EV. No time delay on it. The shifter on the other hand has about a 200ms delay built into it. So with the throttle at 34% (for 1600rpm) I don't move my foot at all. I press the EV button at the exact same time as I pull the shifter to N. The result is that I go from Orange arrows to black arrows with no yellow or blue. RPM goes to zero over the next 2 or 3 SGII refresh cycles. So.. Did the cylinder's park or not? Should I be concerned if they didn't?

Now here's the really cool part. If you hit EV, cram to N, and go from 54kph to 55kph all at the same time the whole transition will be accompanied by the EV-refusal beep-beep, even though the ICE is off. Here's why. Since I don't come off the throttle when I issue the EV request, it is granted, but then (because of speed and throttle) refused. The fun part is I hit N after EV was granted but before refusal was decided. So I crest from a DICE-on to Neutral Warp to NICE-off. I really like it, but don't want to unduly stress the engine (since I'm keeping it for the next 50 years :flag:).

Thoughts?

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This is a very interesting question. Hopefully Hobbit will chime in as I'm sure he would probably know the answer.

I'm not exactly sure what the question was, being buried in
a fair swamp of qualifiers... but assuming it's "how long does
shutdown take", I'm not exactly sure. The hybrid ECU issues
a "stop request" to the engine ECM and then, based on some of
the New Car Features doc I've read and my own observation that
it seems to generally land within 9 degrees of #1 TDC, uses the
motors to position the engine fairly consistently. It doesn't
seem to be 100% exact every time, though, and we do know that
in general we get a spin back up to ~ 1000 RPM before gas and
spark are reapplied anyways. Given the 40-50 amp burst of
battery current it takes to do that, it's also enough time to
probably go around at least once and re-find the timing marks
or at least confirm that they're where the ECM expects so the
re-sync is still presumably faster.
.
Not sure what happens at some of the state transitions where
things seem rougher. If left to itself, the engine will of
course bounce around a little as pistons fetch up against
compression, valve springs resist cam motion, etc. We could
be feeling a little more of that before reaching S4, maybe?
My first EV transition after S1 cat-warmup is definitely, uh,
interesting, for example.
.
This probably doesn't answer the question, but I'll try to
grab some more data today as I go out to look into this
"super highway" thing of yours at the same time. It's labor
day, and I've got a few projects to labor on!
.
_H*

I'm not exactly sure what the question was, being buried in
a fair swamp of qualifiers... but assuming it's "how long does
shutdown take", I'm not exactly sure. The hybrid ECU issues
a "stop request" to the engine ECM and then, based on some of
the New Car Features doc I've read and my own observation that
it seems to generally land within 9 degrees of #1 TDC, uses the
motors to position the engine fairly consistently. It doesn't
seem to be 100% exact every time, though, and we do know that
in general we get a spin back up to ~ 1000 RPM before gas and
spark are reapplied anyways. Given the 40-50 amp burst of
battery current it takes to do that, it's also enough time to
probably go around at least once and re-find the timing marks
or at least confirm that they're where the ECM expects so the
re-sync is still presumably faster.
.
Not sure what happens at some of the state transitions where
things seem rougher. If left to itself, the engine will of
course bounce around a little as pistons fetch up against
compression, valve springs resist cam motion, etc. We could
be feeling a little more of that before reaching S4, maybe?
My first EV transition after S1 cat-warmup is definitely, uh,
interesting, for example.
.
This probably doesn't answer the question, but I'll try to
grab some more data today as I go out to look into this
"super highway" thing of yours at the same time. It's labor
day, and I've got a few projects to labor on!
.
_H*

Yep, you nailed it. Basically when is everything at 9º of TDC. Since I throw it in Neutral, I didn't want to do it before the #1 was at 9º. Since I hit Neutral so close to the "stop request" I wasn't sure if I was preventing some of the positioning.

11011011