Thank you for your comments.
We, Japanese drivers, have never experienced the TCH driving, but my feeling is very strange, because all Japanese Toyota hybrid vehicles act same, ICE shuts off when coasting in Stage 2.

Let me explain how we have seen the stages on Prius. (The key is ICE coolant temperatures.)

Stage 1a: initial 56 seconds warming up. The ignition timing is very late, after nine degrees from top dead center, supplying hot exhaust to catalyst converter. We can't expect enough torque from the ICE, therefore the vehicle is driven by motor.
After the 56 seconds, vehicle goes to Stage 2 if the cootalt temperature is above 40C(104F).
Stage 1b: The warm up idling continues until the coolat temperature becomes 40C(104F). In this stage, the ICE torque is used to drive the vehicle.
Stage 2: 40C(104F) to 70C(158F). Acts as Stage 4, the ICE shuts off at stops and when coasting. (Note: ICE won't shut off until 65C(149F) if your heater is ON.)
Stage 3a: Above 70C(158F), the ICE won't shut off when coasting if you did not exceed 56 km/h(35 miles per hour). If you exceed 56 km/h(35 miles per hour), you temporarily go to Stage 3b. You'll go to Stage 4 after complete or almost stop for approximately 7 seconds idling, or idling check ceremony.
Stage 3b: ICE shuts off when coasting. It looks you're in Stage 4, but you"re not.. The ICE requires the idling check ceremony to go to Stage 4.
Stage 4: full hybrid stage. the ICE shuts off at stops and when coasting. If the coolant was above 66C(151F) when power on after parking for a while, you'll go to this Stage 4 directly.
This is sames as Prius.
We see this when the coolant was above 66C.
As described above, we call it Stage 1a and Stage 1b if the coolant was still below 40C.

Regards,
Ken@Japan

 

(Main post)
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Update for number 12:
"Questions regarding changing your oil and air filter" update to be more generic:
"Questions regarding changing fluids and filters"
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Updated layout as follows (adds new question about coolant and has come other changes).

• Oil
  • Where can I learn more about engine oil?
  • How can I make changing oil less messy?
  • How much should my oil change cost?
  • Why is my oil filter on so tight?
  • What oil and filter should I use?
• Coolants
  • Recommended engine and transaxle coolant change intervals?
• Filters (non-oil)
  • How do I remove the air filter?]

--------------------------------------------

(Post for number 12)


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Make similar layout changes as were made to main post.

--------------------------------------------
Add new bullet for:

• Recommended engine and transaxle coolant change intervals?
  For information about recommended engine and transaxle coolant change intervals, see this post.
  

 

Thanks!
I'll get around to it, but you know, when we're done, we will have, in effect, rewriten the owner's manual!
To prevent that, I'd ask, are these items to be added really frequently (the F in FAQ) asked (that's the A) or are they just useful pieces of information?
The longer the list becomes, the more it's likely to be ignored (basic human nature, few read the manuals if they are more than "X" number of pages...IMHO)

Not losing interest, but not excited about reinventing the wheel, either

 

That's why I try to add it "There have been some questions about the recommended change intervals..."

 

Hi Ken,

Thank you for the detailed explanation. You may be right about Stage 2 being the same. I'll do some further testing with the heater off. Normally I have ECO on, and the heat set to 68F.

I drive out of a subdivision in the mornings, and hit 1 stop sign and 7 stop lights in 3.5 miles. Speeds range from 25 to 40 miles per hour. After about mile or so, the ICE stops everytime I stop at a light. I can accelerate above 35 mph and coast to a stop 2 or 3 times after entering Stage 2 (ICE stopping after the car stops), but the ICE will not stop while coasting down from above 35 mph. After about 3 miles, the ICE begins shutting off while coasting down from above 35 mph (Stage 3.)

If I'm lucky I can then force the ICE to idle at the last light for 7 seconds and go to Stage 4. Unless it is above 60F, I rarely can enter Stage 4 at this time. After the last light I'm on the freeway for 30 miles.

Oddly, If I drive the freeway portion in Stage 3, it takes a very long time idling to enter Stage 4, often a minute or so.

I hope this helps explain why I believe Stage 2 on the TCH will not let the ICE shutdown when coasting.

 

Hi,
Thank you for your explanation.
I believe we have to shut off the heater and use a coolant temperature meter, such as ScanGauge-II, for the real experiment on stages.

Ken@Japan

 

Ken and Larry,

Are there any updates that should be made to the FAQ? It isn't fully clear -- to me at least.

 

Larry and Nash wrote: TCH will not let the ICE shutdown when coasting in Stage 2.
Ken@Japan wrote: It is very strange, because all Japanese Toyota hybrid vehicles act same, ICE shuts off when coasting in Stage 2.

Action needed: Real experiment is required by a TCH driver who has ScanGauge-II.

Ken@Japan

 

I think the bulk of the modifications are ready to be edited into the FAQ.
There are extra items that we can edit in at a later date, including a more detailed understanding of the ICE as discussed by ken1784.
In any event, in the next week I will ask admins to open up the FAQ so I can edit it.
Please review items in post #16, which will serve as my guide for the edits. Please feel free letting me know what tweaks should be made.
Thanks and keep working on the ICE shutdown issues, etc.

 

Don't forget this:

https://www.greenhybrid.com/discuss/...tml#post160939