Okay... after a page and then some of back & forth, I think I understand what you're trying to say, bikenfool, and now that I understand it I think your question is valid.
The most difficult thing to get past for me was your use of the phrase "Constant Speed". But if I look at your wording here:
Quote:
Originally Posted by bikenfool
Method 2. Constant speed, begin a coast before the top of the hill so the speed at the top is the same as for the DWL case.
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... what I realize is that you are describing Pulse & Glide. Granted, the way P&G is typically described is that it is done on a flat/level section of the road, but the idea is the same whether on an uphill or on a flat: increase the load so that the energy conversion from fuel to HP is more efficient, then when you reach a particular target you switch to a glide (engine on or off). With traditional P&G, your target may be particular speed at which point you begin your glide; with your Method 2 approach, you maintain your speed to a point where your glide would take you to the top of the hill (and where your speed at the top of the hill would be the same as the speed you would have if you had used DWL). While your speed does not increase as you go up the hill, you are accelerating (the acceleration on the flat ground will result in greater speed, whereas overcoming the force of gravity (which for the engine is indistinguishable from acceleration on the flat ground) will maintain a steady speed on the uphill).
So I would say the correctly worded methods to compare would be:
- Method 1: DWL up the hill
- Method 2: P&G up the hill (where the "pulse" is just to maintain your speed, and your glide starts where the target speed at the crest of the hill is equal to the speed at the crest using DWL)
(both methods assume that the measuring points are from the base of the hill to the crest of the hill)
Now, I think, you have a valid comparison, or at least one where the answer is not so clear cut. I think it depends a lot on the car and on the hill. For example, with my Honda VX it was not even possible to maintain a constant speed up the ~1 mile grade that is near my house unless I went full throttle (full enrichment). DWL was definitely more efficient in that case. With my TDI, I can easily keep a constant speed up, and I will typically do the "pulse" (maintain steady speed) up the hill, begin my glide before I reach the crest, and then continue my glide down the other side of the hill. I haven't tried to do a comparison on the same hill using DWL with the TDI, but it might very well be possible that the pulse uphill plus a coast before reaching the crest might be comparable to DWL under certain conditions.