Instantaneous MPG readings for best fuel economy

Just wanted to post that I seem to be able to accelerate in the 1 to 2 MPH per second range on a flat while keeping MPG > 0.5 x MPH. Typically when I get close to or above 2 MPH per second I start to see MPG < 0.5 x MPH. If there is much of an incline at all, I usually have to accelerate slower than 1 MPH per second to stay in the target range.

 

Japanese hypermilers are saying that the 76-80 (MAX:200, 38-40% on CAN-view) CAN accelerator pedal value is the best for FE on accelerating, no matter what instantaneous MPG readings are.

Ken@Japan

 

Does someone have both Can-view and a Scangauge and can correlate the 38-40% of Can-view to the TPS of Scangauge.

Wayne

 

<div class='quotetop'>QUOTE(ken1784 @ May 8 2007, 02:09 AM) [snapback]437370[/snapback]</div>

Now that's a valuable piece of information.
Thanks for relaying that.

Dave M.

 

<div class='quotetop'>QUOTE(dmckinstry @ May 8 2007, 03:19 PM) [snapback]437669[/snapback]</div>

Yes, thank you Ken.

Do I read that right - they shoot for (what in the old days would have been called a) throttle position, now properly termed accelerator pedal position?

Second, can anbody verify that the pedal position as measure on the CAN-view is linear in the actual physical pedal position? So does that actually correspond to pushing the pedal 40 percent of the way through its entire travel?

That's certainly in the ballpark of a rule-of-thumb mentioned in a prior thread (Dr. Fusco?), which was to do a brisk accel with the pedal one-third of the way down - 33%, 38%, who's counting.

If it's good enough for me to shoot for pushing the pedal literally to 40% of the travel, then I can gin up a simple physical device (like with duct tape and a playing card) that will tell me when I have my foot in the right position. Or Two wires and a light bulb if I want to play high-tech redneck.

Can anybody validate the concept (sensor based 40% of pedal travel is about right, and sensor is linear in actual physical pedal position) before I get duct tape adhesive on the inside of my Prius?

 

<div class='quotetop'>QUOTE(JimboK @ Apr 30 2007, 07:57 AM) [snapback]432458[/snapback]</div>

Jim, I applaud your efforts but I don't think this will work and in some cases may not even be possible.

Example: A 15 mile drive at 30 mph. According to your formula, my maximum mpg (30 x 1.2) is limited to 36. Similarly at 40 mph, max mpg is 48. I know I can do a lot better than that without even watching the MFD or doing any math. Or did I miss something?

 

<div class='quotetop'>QUOTE(FireEngineer @ May 2 2007, 09:46 AM) [snapback]433883[/snapback]</div>

I share Highly ImPriused's question on this issue. I just installed a ScanGauge II. Before I did that I was simply trying to maintain the highest instantaneous MPG numbers possible on the MFD. That included very ginger accellerations. Now that I have the ScanGauge I see that when I'm doing that I'm at 1280 RPM or so, way under the sweet spot of 1700 - 2300 RPM. But if I go for the sweet spot my MPG goes way down. So the only way I can see that trying for the sweet spot would IMPROVE MPG is that it gets you up to glide speed faster, even though during the pulse you're not getting as good MPG. Is that correct?

My other question is that Wayne Gerdes says in his P & G article over on cleanmpg.com that proper pulse looks like this:

[attachmentid=9505]

But when I get no EV assist and flow to instead of from the battery like that, I see that my RPM is in the 1280 range again. Seems contrary to what everyone's saying here, no?

Also, anyone have figures on what's a good LOD (engine load) target number, independent of RPM?

Thanks in advance for helping a newbie!

 

<div class='quotetop'>QUOTE(JimboK @ Jul 7 2007, 04:55 PM) [snapback]474754[/snapback]</div>

For whatever it's worth my experience without added instrumentation is that after learning the MPH<2xMPG rule I have substantially increased my MPG from about 53 to 60 a difference I mostly attribute to this rule during my uphill return from work. In reality I can force 65MPG in my drive but then it gets too laborious. Also I don't want to focus too much on the MPG readings. Currently from a 9.5 gallon fill-up I'm at 277 miles with 3 pips gone.

I have been wondering about a device that indicates best accelerator pedal condition also. It seems to me that Toyota should have provided an add-on button/accessory that forces the ICE to around 1500-2400 RPM. There must be a way to do this and I personally think Toyota could *easily claim >60mpg with this function.

 

JimboK thanks for the advice. I generally try to be at around MPH~1.5xMPH unless I'm being pushed or are starting from a stop when I aim to not exceed the 2xMPG mark. For the record I got 58mpg going 55-65MPH on the highway in considerable traffic and I've only had the car for 2600 miles. I expect more tire tread wear and perhaps this inexplicable break-in people speak off.

I'm wondering if it's better to use the battery range from 3-7 bars or to pulse hard and help maintain the 6 bars like the Prius wants.

I think the answer depends on the speed of the warp stealth, be it between 30-40MPH in the suburbs or 50MPH in the back roads. Anyone know?

 

<div class='quotetop'>QUOTE(JimboK @ Jul 7 2007, 04:55 PM) [snapback]474754[/snapback]</div>

Thanks Jimbo! I'm going to try keeping RPM in the 1700 - 2300 range for pulse and see how I do as compared to my excrutiatingly gradual accelleration up until now. B)

One more question: How do you guys handle the pre-glide period before you get to stage 4? I've found that I can do a quasi-glide after getting up to speed, at least toward the end of this period, where the ICE is still on, the screen looks as I posted above, and at times the iMPG will climb into the 90's. It helps on my 2.5 mile trip into work, because I often don't get to stage 4 until half or 3/4 of the way through, even now during summer. But of course RPMs are very low during this quasi-glide, so the engine is "loafing". Is there a better way to handle it?

Thanks!

 

<div class='quotetop'>QUOTE(JimboK @ Jul 8 2007, 12:18 AM) [snapback]474933[/snapback]</div>

I know. I want one. Where I live now I don't have a garage or any other way to plug in. I may be buying a condo soon, and one of my main motivations is to have a garage. Yes, that's right, I'm not doing it for me, I'm doing it for my car... :blink: Of course, if I do buy it, my commute will go from 2.5 miles to about 16 miles (non-freeway) anyway, but still I'll need it for the Cleveland winters...

I am going to block my upper grill this weekend now that I have the ScanGauge to monitor coolant temps. BTW, what is the danger zone for coolant temp? Also, in the 5 stages artice ( http://techno-fandom.org/~hobbit/cars/five-stages.txt ) it says that stage 3a occurs at 163.4 F, but doesn't give a temp for stage 4. Is that temp sufficient for stage 4 after a full stop, or is there another threshold that was left out?

Thanks again for all the knowledge!

Duane

 

<div class='quotetop'>QUOTE(dprice23 @ Jul 8 2007, 02:07 PM) [snapback]474953[/snapback]</div>

The coolant thermostat starts to open at 82C and it gets full open at 95C. The cooling fan starts at 100C.
We observe the typical coolant temp is 88C (190F).
up to 95C (203F): green zone
95C - 100C (212F): yellow zone
100C and above: red zone

There is no other threshold for S4.
We just need the idling check ceremony to move from S3 to S4.

Ken@Japan

 

Thanks Ken! And I appreciate all the knowedge you bring from the Japanese hypermilers. I've learned a lot from your posts.

I tried staying in the sweet spot on my 2.5 mile commute home last night. Although I did get to stage 4 much more quickly than I did with my previous ginger accelleration, trying to maintain high iMPG method, I only got a little over 39 MPG for the trip, whereas before I was able to get into the 50's. It's probably just too short for the glides to offset the lower initial MPG. I have a longer drive today, so we'll see how I do.

 

<div class='quotetop'>QUOTE(JimboK @ Jul 7 2007, 09:22 PM) [snapback]474858[/snapback]</div>

Thank you, Jimbok, that's useful information. I'm not up to installing a can-view, but I'm pretty sure I can rig something simple to tell me when I have the pedal at 40%.