Open Loop / Closed Loop Question - Page 2 - GreenHybrid

Dan · #11 (**permalink**) 07-23-2008, 09:33 AM

Quote:

Originally Posted by nyceshirtz

I feathered the gas pedal when the stars and planet were aligned. i was able to travel appx 2 miles in open loop at appx 63mph in "Warp Stealth mode". Energy screen looked just like in EV mode under 39 miles per hour with the arrows traveling from the battery to the wheels. No ICE arrows at all. RPM was about 985 with 0.00 GPH. FE jumped higher by 2mph. I was also able to go into ""WARP STEALTH MODE"." for a shorter duration. This time the arrows travelled from the wheels to the battery, similar to regen braking. MPG also improved, but not as dramatic as the previous "WARP STEALTH MODE". But my biggest question remains: HOW DO I GET THE TCH TO GO INTO "Warp Stealth mode". WHAT ARE THE KEY PARAMETERS THAT EFFECT THE ECU'S DECISION ALGORITHM TO ALLOW "WARP STEALTH MODE".

hate to keep harping on it, but you'll have to get a gauge. From my review, I found:

Must have NO accessory load (no AC, no headlights, no fan)
Must be in S4 via a forced S4 transition.
Per the previous statement, Engine coolant temp must be above 70c
ScanGauge must be used to find and hold gas pedal pressure at correct state ("gps" XGauge). Start at 1.0% and increase (by 0.5% increments) up to 7.5%
Must be at 5 bars of battery charge or more, trying it with 7-8 bars simplifies things considerably.
Must be in "D" not "N" or "B"
Must be traveling between 45 and 55 MPH. Above 55 MPH this gets expedentially harder to hit.

You should see WS triggered by watching IGN on the ScanGauge register the same value as an ICE-off glide. Believe this is IGN 5, but I'm no longer certain.

Although Neutral Coast will drop the RPMs, I question as to whether or not it cuts the injectors. My hunch is that it does not, since when I do it in a cold engine, the temperature continues to rise (suggesting a boom in the chamber).

11011011

FastMover · #12 (**permalink**) 07-23-2008, 12:16 PM

Quote:

Originally Posted by Dan

...Although Neutral Coast will drop the RPMs, I question as to whether or not it cuts the injectors. My hunch is that it does not, since when I do it in a cold engine, the temperature continues to rise (suggesting a boom in the chamber). 11011011

Correct! and it also does not, whether by design or not, completely cut the fuel -- again as evidenced by the temperature, and also by the very slight fuel consumption shown on the SG over an extended coast in "N".

SPL · #13 (**permalink**) 07-24-2008, 11:10 AM

A few comments on these very interesting posts:

Dan — I believe that the TCH's ICE has an 82-degree C thermostat. I hadn't thought of the need to circulate the coolant to cool the engine when it's stopped when its coolant is very hot (and the internal cabin heater, with its electrical pump, isn't being used). Interesting!

I have a ScanGaugeII with code version 3.01. (I'm waiting for Ron DeLong to get the bugs out of his new code before I get mine updated!) My LPH reads either 0.1 or 0.2 (and IGN reads 5) when the ICE is open-loop — in either EV-mode, fuel-cut mode, or in 'N' before starting the ICE. The average of these two readings is 0.15, and the SG is clearly displaying this to one decimal place. This supports your comment. Yes, these readings ought to be nulled to zero.

nyceshirtz — You ask how to force the TCH into fuel-cut mode. The Repair Manual tells the pre-requisite conditions under which it will go into fuel-cut in the attached pages ES-275to288 dealing with the oxygen sensors and how to test them for correct operation. See pages 280 (bottom) to 281 (top) and especially items (i)-(k) [item (h) appears spurious!], and pages 284 and 285. I hope this helps.

Stan

nyceshirtz · #14 (**permalink**) 07-24-2008, 06:58 PM

Quote:

Originally Posted by SPL

The Repair Manual tells the pre-requisite conditions under which it will go into fuel-cut

(i) Drive the vehicle at a proper vehicle speed to perform fuel-cut operation.
HINT:
Fuel-cut is performed when the following conditions are met:
• Accelerator pedal is fully released.
• Engine speed is 2,500 rpm or more (fuel injection resumes at 1,000 rpm).
(j) Accelerate the vehicle to 40 miles per hour (64 km/h) or more by depressing the accelerator pedal for at least 10 seconds.
(k) Soon after performing step (j) above, release the accelerator pedal for at least 4 seconds without depressing the brake pedal, in order to execute fuel-cut control.
(l) Allow the vehicle to decelerate until the vehicle speed declines to less than 6 miles per hour (10 km/h).
(m) Repeat steps from (h) through (k) above at least 3 times in one driving cycle.

Thanks Stan! I'll try it out and report back!

SPL · #15 (**permalink**) 07-25-2008, 09:44 AM

nyceshirtz — Steps (l) and (m) are not necessary to achieve fuel-cut mode; they are part of the test procedure for checking the operation of the oxygen sensor. Steps (i)-(k) are what you need to try. In my experience the TCH will usually switch in and out of fuel-cut mode quite easily (at least after the first time) at engine speeds well below 2500 rpm. Perhaps 2500 rpm is needed the first time only.

Stan

Smilin' Jack · #16 (**permalink**) 07-25-2008, 10:25 AM

Is there a comprehensive writeup on the various "modes" ?

fuel cut mode
warp mode
stealth mode
warp stealth mode
heretical mode

and/or of the 4 "stages of operation" ?

and how these "modes" are related to the "stages" ?

Thanks for any enlightenment !

Dan · #17 (**permalink**) 07-25-2008, 11:35 AM

Quote:

Originally Posted by Smilin' Jack

Is there a comprehensive writeup on the various "modes" ?
fuel cut mode
warp mode
stealth mode
warp stealth mode
heretical mode

and/or of the 4 "stages of operation" ?

and how these "modes" are related to the "stages" ?

Thanks for any enlightenment !

I have an OBDII scan tool that will read the Injection timing, and I'd queue off that for all this stuff. Basically IGN=5 is the indicator to watch.

Fuelcut = IGN:5
Warp = IGN:5
Stealth = IGN:5
WS = IGN:5
Heretical = IGN:18 with RPM < 1300 and MPH > 50 mph

The best way to find all of these is with a CANbus analyzer (yep, I got one of them too). With it you can read the pedal pressure on the gas pedal and use it to dial in these specific modes with astonishing accuracy.

Sorry It all comes down to tools, but I don't have an easy answer.

PM me if you want more detail....

11011011

SPL · #18 (**permalink**) 07-25-2008, 12:02 PM

As a side comment on the open-loop/closed-loop issue, I have consistently noted the following behavior as the TCH transitions from:

open-loop, fuel-cut coasting at speeds above 64 km/h (~40 mph) with the ICE being spun at ~1000 rpm by MG1, and with the Canadian FC-gauge reading precisely 0 L/100 km (or the US FE-gauge reading precisely 60 mpg); to
open-loop, pure-EV mode at speeds below 64 km/h with the ICE not spinning at all, and with the FC/FE-gauge reading in the blue E-mode region.

The ICE is given a brief (<1 s) spurt of fuel + spark during the spin-down of the ICE. The FC/FE-gauge makes a very small upward movement before it sinks down into the blue E-mode region. At the same time, the other relevant variables (IGN, TPS,...) also momentarily change, before returning to their previous values. I'd guess that the fuel "blip" is something to do with Toyota's attempt to get as imperceptible a spin-down of the ICE as possible. See the attached Toyota US patents.

Stan