HSI details

Strange. My Garmin shows the Prius is only 1 mph off at 35 and 65

 

My Garmin nuvi 260w, the stored trip log, and the mile markers by the side of the road with an iPod Touch stopwatch show our 2010 Prius indicates 1 mph high. Interesting, the trip meter average speed is dead on. But this was only for durations of +10 miles with the speed managed by the cruise control on relatively flat land.

Bob Wilson

 

FWIW here is Garmin data for another run with the HSI shy of the right triangle. It does show the elevation pretty flat but that's about all really. Maybe cos I've got a basic Garmin but the waypoints at these speeds are 10 seconds and more apart and only accurate to a second. (Strange that at low speeds the waypoints are 1 second apart.)
I saw a max much higher than that shown and the Garmin itself shows 90 was achieved.

It is difficult to keep the HSI just shy of the right triangle. It keeps falling away and then you seem to have to apply more throttle to keep it there. The feeling is that as the speed increases you need more and more throttle to keep the HSI at that point.

I don't feel I've got near what is possible.

	Column 1	Column 2	Column 3	Column 4
0	Elevation(Metres)	Time(Seconds)	Distance(Miles)	Speed(mph)
1
2	12.15	12	0.1699156	50.97
3	12.15	12	0.1741885	52.26
4	11.67	15	0.2351334	56.43
5	10.71	14	0.2275897	58.52
6	9.75	14	0.2987620	76.82
7	9.27	13	0.2909098	80.55
8	10.23	14	0.3345445	86.02
9	11.67	12	0.2898496	86.95
10	13.60	9	0.1992136	79.68
11	16.96	14	0.2945532	75.74
12	19.84	9	0.1947679	77.90
13	22.25	10	0.2248115	80.93
14	24.17	9	0.2092138	83.68
15	25.61	8	0.1786248	80.38
16	27.53	10	0.1928785	69.43

 

I plotted the power changes that would reflect the change in potential and kinetic energy:

This data pattern is consistent with a non-linear coefficient of drag. What this means is somewhere between 25 (58 mph) and 34 m/sec (78 mph,) the ZVW30 may have a local drag minimum. Certainly this is an area I'm going to be investigating in the future.

One question about your GPS data, does it include an absolute time stamp? I took the 'seconds' as a duration at a given value. To plot the elapsed profile, I added up the individual seconds.

There is one other possibility, traction battery recharge. I noticed that a previous Pulse and Glide segment had brought the traction battery indication down to 3-4 bars. When I started the last equivalent steady speed, there was a significant charging of the traction battery in the first part of the 14 mile run. That steady speed run had an unexpected, low mileage compared to the the first, steady speed run.

There are other hypothesis that could explain this pattern.

Do you remember the traction battery bar level at the beginning and end of the run?

Thanks,
Bob Wilson

 

Yes, my Garmin is a nuvi 200W so the data format is probably similar to yours.
Date part removed:

	Column 1	Column 2	Column 3	Column 4	Column 5
0	Elevation(Metres)	Time	Elapsed (Seconds)	Distance(Miles)	Speed(mph)
1	12.15	09:42:23	12	0.1699156	50.97
2	12.15	09:42:35	12	0.1741885	52.26
3	11.67	09:42:50	15	0.2351334	56.43
4	10.71	09:43:04	14	0.2275897	58.52
5	9.75	09:43:18	14	0.2987620	76.82
6	9.27	09:43:31	13	0.2909098	80.55
7	10.23	09:43:45	14	0.3345445	86.02
8	11.67	09:43:57	12	0.2898496	86.95
9	13.60	09:44:06	9	0.1992136	79.68
10	16.96	09:44:20	14	0.2945532	75.74
11	19.84	09:44:29	9	0.1947679	77.90
12	22.25	09:44:39	10	0.2248115	80.93
13	24.17	09:44:48	9	0.2092138	83.68
14	25.61	09:44:56	8	0.1786248	80.38
15	27.53	09:45:06	10	0.1928785	69.43

Sorry no.

 

I've been trying to figure out something that may fit here. There are several long, gradual uphills on my way to work and I can feel a huge difference in the engine/MPG when I am going 65-70 versus, say 55-60.

Some of this may be that with a 55 MPH speed limit, the higher speed lets me bleed off more MPH to maintain engine RPM and MPG -- and perhaps not notice the speed drop if I'm more focused on traffic and mileage -- but I've definitely noticed times when this does not seem to be the case.

I was speculating that perhaps the engine has a sweet spot in that range corresponding to 65 MPH interstate speed limits, but perhaps there's a drag thing happening. (Or both.)

 

Thank you!

With the individual data points, I was able to construct a spreadsheet and convert to SI units for an energy analysis. I've attached the spreadsheet so hopefully you or anyone else could use it to analyze their own GPS data. BTW, some of the data points look interesting, 9:44:20-9:44:55. I'm not sure the non-linear coefficient of drag hypothesis makes sense.

Thanks,
Bob Wilson

 

Thanks for the bump, hobbit. I find the HSI to be an alluring gauge, though I can't say I've ever really understood it that well. Before I had any idea what it really was telling me, I felt that it was the most useful of the MID displays.

Please keep this thread updated with your comments, observations and questions.

Oh! Almost forgot:

I believe that in a short (but steep!) hill climb I was able to reach the Power area in the HSI while in EV mode. I know I've gone far, far to the right (on the HSI meter) in EV, while I think I've also "broken" into the EV mode while not forcing the ICE to start.

 

Today on the way to the airport I had full bars of battery less one and while in EV Mose had the HSI up to power with about half filled without ICE light. I've never seen it go that high without the excessive gas message. Also, I found as I backed off to turn off EV mode before I hit 25mph, if I didn't let off completely, the ICE would briefly turn on before quickly shutting down.

Also it seems as soon as coolant temps drop below 160 then I was back at 15mph EV max speed. I was above 160 but using the heater brought it down.

Anyway, EV mode in the power range. Interesting!

 

Not sure if this has been noted before, but when the battery is full or full-1bar, I can take full stealth mode up past the centerline a bit without firing the ICE. It will get up to almost the end of the leaf when the battery is full, presumably because she is trying to bring down the charge to the preferred 6 bars.

 

OMG!

If I may: they are fully readable under Webkit (Safari, Chrome, etc.) and also under Firefox. I've booted that old fashioned Vista to try it under the outdated IE 7 and everything is fine.

ASCII brings us back to the '60. Unicode was adopted in the '90 (the sole internal character set of Windows since NT in '93!). ...not that I don't keep good memories typing Alt-ASCII code on DOS to get accented chars! (Alt-130 = é, 138 = è, 133 = à... still works in Vista! )

I didn't even thought someone could still have issues like this today!

In remembrance of ASCII and its legacy:

Sorry for the disruption...
:focus:

 

I think he is doing it intentionally, as part of his malware protection strategy. Some phishers are using the newer fancier fonts to make some bogus URLs look like the real thing, to slip past the wary eyes of otherwise alert users.