Mini Test: Driving With Load VS. Cruise Control - DWL (more or less) busted!

[Peakster]

I did a little A-B test tonight comparing 'driving with load' versus cruise control and here are my results:

Temperature: 11*C
Winds: coming from the south @ 15km/h.
Route:
Attachment 374

Here's the YouTube Video of the test.

Driving with Load:
FE average: 60.5 mpg
Speed Average: 48 mph

Using Cruise Control:
FE average: 60.2 mpg (a 0.5% mileage decrease if you're picky)
Speed Average: 48mph

Looks like using cruise control is virtually just as good as keeping a steady throttle and letting the car speed up and slow down as it likes.

I tried to make a video of the test & everything went well except the last clip where I announce the mpg with the cruise: It didn't record on camera !!! Now I know how people feel when they get all geared up for a UFO sighting and miss the final alien shot !

I'll probably still post it later because there's some funny parts where a guy driving an SUV gets all angry after I point the camcorder at him, and me full-throttle accelerating like mad so I can simply merge onto the highway.

[zpiloto]

What kind of route, weather and terrain were you dealing with. I would be really supprised if that held up to more testing. I done hill climbing (1/2 mile 6% grade) with load and without and there is a significant difference between the two. Then again I don't have that data to show since my computer crash.

Just saw the map. Was it the same directions both time.

[Peakster]

Originally Posted by zpiloto

What kind of route, weather and terrain were you dealing with. I would be really supprised if that held up to more testing. I done hill climbing (1/2 mile 6% grade) with load and without and there is a significant difference between the two. Then again I don't have that data to show since my computer crash.

The route is fairly flat, but enough difference in altitude where my speed drops/climbs considerably. I'll definitely post the video so you can see the road conditions. It's definitely worth considering a A-B-A-B test.

Computer crash eh? Looks like the UFO thing is effecting you too!

Originally Posted by zpiloto

Just saw the map. Was it the same directions both time.

You bet. North to south DWL, drove back to the top, and did the same exact route with cruise @ 48mph. The video is loading on YouTube as I type.

[Snax]

I think more data is imperative when comparing to cruise controlled speed. As I found with my brief testing of my grille blockoff, there seems to be too much variance to conclude anything even on a 20 mile round trip.

With Blockoff,

leg 1, 22.5 MPG
leg 2, 21.7 MPG

Sans-Blockoff

leg 1, 21.8 MPG
leg 2, 22.0 MPG

I also believe that the difference between load adjusting and cruise are more pronounced when you throw some significant hills in there, particularly when you get into being able to anticipate the crest of a hill and initiate a coast sooner. Plus, those with automatic transmissions stand to prevent kickdowns and fuel sucking over revving on the ascent with load adjusting.

[zpiloto]

Peak in my search on acetone I found that this(second one down) experiment made google. Now you can say that your work has been published.

[Peakster]

Originally Posted by zpiloto

Peak in my search on acetone I found that this(second one down) experiment made google. Now you can say that your work has been published.

That is awesome!

Now let's see if my Acetone Test will make google too (just did the test today and about to make a thread on it ).

[MetroMPG]

Originally Posted by Snax

I also believe that the difference between load adjusting and cruise are more pronounced when you throw some significant hills in there

I think you're right there, Snax. Hills will make the DWL technique's advantages more obvious.

Also, I was too simplistic when I described DWL as maintaining a constant pedal position, Peakster. Thats more like "DWL lite".

"True" DWL would have you monitoring your SG for engine load (or an engine load-related parameter like instant MPG). If you're DWL, your MPG should stay constant as you climb & descend grades. This will likely mean that you have to let off the accelerator progressively as your speed falls in a climb (maybe even downshift too), and slowly re-apply pressure after the crest.

So "True" DWL (as opposed to DWL Lite) by its very nature will also probably result in a slower average speed over a given route than driving that route with the cruise control (assuming the same starting speed). So you also face less aerodynamic losses.

[Peakster]

Originally Posted by MetroMPG

Also, I was too simplistic when I described DWL as maintaining a constant pedal position, Peakster. Thats more like "DWL lite".

"True" DWL would have you monitoring your SG for engine load (or an engine load-related parameter like instant MPG). If you're DWL, your MPG should stay constant as you climb & descend grades. This will likely mean that you have to let off the accelerator progressively as your speed falls in a climb (maybe even downshift too), and slowly re-apply pressure after the crest.

Whoa! Crazy concept. I thought it was as simple as keeping a steady GPH (my cruise control tends to lessen the GPH while going downhill and increase it while going up grades). "DWL lite" - that's funny !

So "True" DWL (as opposed to DWL Lite) by its very nature will also probably result in a slower average speed over a given route than driving that route with the cruise control (assuming the same starting speed). So you also face less aerodynamic losses.

That was actually one of the things that interested me. Is it that DWL increases FE because the average speed is slower than if we were to drive in cruise? Since I drove the 7 miles doing 48mph average using DWL-lite, for a good cross-check, I thought it would be obvious to simply set the cruise to that same 48mph to keep it a constant variable (since the time travelled needs to be the same in order to compare apples with apples, no?).

[MetroMPG]

Originally Posted by Peakster

Is it that DWL increases FE because the average speed is slower than if we were to drive in cruise?

Good question