New Prius - "Super Highway Mode" Technique (SHM).

[Dan]

Update: Jump to post #163 for some new revelations....

If your not following Wayne's Prius II thread, we found an interesting spot on the efficiency curve for the Prius II. There seems to be a sweet spot right before the injectors cut out on the way to Warp Stealth. The elusive part is that it looks like it's BELOW the loafing zone for highway driving. Basically it's another "drive-to-a-number" technique, but instead of driving to RPM, you drive to IGN.

Google told me that Ignition Advance (IGN) has to do with when in the power stroke to spark the fuel. The ECU will slide this number around as you vary the power demand on the engine. Low numbers are better than high numbers. Anyway, for the Prius, the ECU seems to hang out on an IGN of 14 whenever it's feeling really efficient. What RPM and advance of 14 yields varies widely based on speed, which explains some of the odd numbers that jump out on HW segments. What I've seen is that IGN 14 can happen at 1600 RPM in the city and 1200 RPM for the highway.

Here's a clip from Wayne's Prius Thread about SH mode.

EDIT: Added IGN: -10

Originally Posted by Dan

Dial in IGN as one of your gauges and watch what happens when hold IGN of 14. Here's the decoder:

• IGN: -10 = Manditory S1 ICE-on.
• IGN: 5 = Fuel Cut or ICE-off
• IGN: 10 = Idle
• IGN: 13 = Very hard to hold, happens at about 1100 rpm on the HW
• IGN: 14 = SWEET SPOT MPG = 1.5 x MPH and on a flat you can hold it for miles unlike WS. I get slightly better numbers with WS P&G, but man this is the closest I've seen! Something else interesting is that IGN 14 is also what my city driving Pulses seem to hit consistently when at 6 bars. It's a whole lot easier to hold an IGN number than an RPM number, and the RPMS seem to self regulate to the IGN number.
• IGN: 15 = Close second to IGN 14, and allows for longer distances.
• IGN: 16 = Hardly ever saw it at 6 bars, seemed to always be on the way to 17 or 15
• IGN: 17 = FE falls off here, and I recommend avoiding 16 and 17. Possible loafing
• IGN: 18 = WS Pulse rate. This is a perfect pulse rate if your gonna WS P&G. Pulse at IGN 18, Glide at IGN 5.
• IGN: 19+ = Very fuel thirsty, I recommend avoiding these unless your in a "gotta floor it" moment.

I was using my highway segment as a learning session this weekend, so I only spent about 30 miles on SH mode but the numbers looked good. Came out to about 67 mpg for SH. Basically my driving strategy for SH mode was to hold IGN 14 as long as possible. It seemed that on flats, you can ALMOST maintain speed at this state. Might be a fun mode to try on a distance draft or with a strong tailwind. For the terrain and weather (gobs of rain) I was in, speed would slowly bleed off. So I was using SH as my glide state in a highspeed P&G technique. I'd pulse up to 90 kph (56 mph) at my usual 1600 RPM range. This consistently translated to an IGN value of 18, if you want to go off that (which I would recommend). Once at 90 kph I'd come off the throttle and watch the IGN numbers drop till I was at exactly 14. I'd hold this for MILES until I was down to 80 kph (50 mph), then I'd pulse up again.

Now for some more odd stuff. I'm not sure which OBD-II request SGII is sending down to get IGN, but it would stand to reason that it was requesting "Timing Advance". Problem is, that the Prius reports that it doesn't support this PID. So I'd expect to get a value of -64, but the values it sends back seem valid. Another point of interest is rounding. OBD-II reports timing advance (IGN?) in half degrees. So the scale may look like {12.0, 12.5, 13.0, 13.5, 14.0, 14.5, 15.0, 15.5}. So if you notice that sometimes 14 is better than other times, you may be dancing between 13.5 and 14 and not know it. The new XGAUGE feature should fix this.

Another odd thing is that a low IGN is supposed to be BAD. According to the SGII manual. It's possible that this is simply the result of being on an Atkinson/Miller (Prius) cycle engine instead of an Otto cycle engine.

This stuff is still in very early beta right now, and there haven't been enough confirmations but Wayne and I have both seen rather consistently that IGN 14 on the highway holds FE over 70 mpg for as long as you can hold it. If you can hold IGN 13, go for it. You should see triple digit FE. I don't think 12 is possible, and going for it will likely transition you to a WS glide (IGN 5).

Anyway, next time your driving around, look at what happens (city and highway) when you hit IGN 14.

Please let us know on this thread if you can confirm good HW segments in SH mode.

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[brick]

How consistent is that 1200RPM sweet spot on the highway? If you think I can pretty much hit it by watching the tach then I'll give it a shot this week. Or should I concentrate more on MPG=MPHx1.5? I do 40mi/day at 55-60mph so this is exactly the kind of thing that interests me.

[Dan]

Replace RPM on your SGII with IGN. Watch IGN and try to keep it at 14. IGN is on page 8 of the ScanGauge Manual. If you just watch RPM or MPG you can't hold it, but if you just watch IGN you should be able to hold it for the majority of your highway miles.

It seems a little underpowered to keep your speed consistent so you will loose 1 mph about every minute or so, depending on terrain.

The key is to change your gauge display to display IGN.

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[brick]

OK. The thing is I haven't been using the SG at all recently but maybe I'll put it on the dash again to give this a shot.

[Dan]

If your using CanView it has Ignition Timing (AKA Ignition Advance; AKA Timing Advance).

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[xcel]

Hi Tim:

___My baton has been passed to you knowing you have that god awful higher speed highway run. Just setup IGN as one of the 4 displays and camp it at 14 once you have reached a high 6-bar state. I will be very interested in reading your take on it given the amount of highway miles you have to run every day? The higher speed comments will be very interesting reading for many of us here?

___Dan, IGN14 is a “Kick @$$ Ride”, isn’t it

___Good Luck

___Wayne

[JimboK]

Originally Posted by xcel

Just setup IGN as one of the 4 displays and camp it at 14 once you have reached a high 6-bar state.

For clarification, where does this additional step come in (quoted from the other thread):

Originally Posted by xcel

There appears to be two modes to 6 bars of SoC for the highway driver .... When you see the quick flashing yellow arrows from the pack and MGSet mimic, back off just a touch and reapply when it disappears. I mean just a touch so that you are not using the pack.

[xcel]

Hi Jim:

___While driving to IGN14, when you reach 6 bars, there will be an initial area where 70 + is not available. 60 + is but not 70. This has to be a lower 6-bar SoC state but I am guessing on this? After a minute or two more of highway charging, the high 6-bar state arrives and that 70 + SHM is available afterwards.

___Good Luck

___Wayne

[Dan]

Originally Posted by JimboK

For clarification, where does this additional step come in (quoted from the other thread):

IGN is as a ScanGauge gauge. Just like LOD. Personally I've selected my 4 gauges as RPM, IGN, MPG, WT.

Once you have that on, try to keep IGN between 13-15 whenever the ICE is on. The one time you can "permit" yourself to take IGN above 16 is when you need to get to speed or recover lost speed (from a long IGN14 glide) on the highway.

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[Dan]

Found another IGN indicator. IGN -10 is when your in the mandatory S1 ICE on mode. The cool part is you can now find out when the EV button is "enabled" after the 60 second S1 run. As soon as IGN goes positive, EV is enabled.

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