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Old 08-13-2017, 09:59 AM   #1 (permalink)
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Modified Pulse and Glide.

I have started using a modified version of Pulse and Glide, when driving on a busy highway. What I do is briskly take the revs up to 2800 rpm then lift off the throttle and let DFCO do its stuff, until the revs drop back to 2200 rpm. I keep in gear and once I reach 2200 I briskly accelerate back to 2800 again.
My speed doesn't vary by much, and I disrupt the traffic very little. Most following motorists probably don't even notice the gradual change. I seems to keep my average mpg up quite well.

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Old 08-13-2017, 10:18 AM   #2 (permalink)
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The main benefit of pulse and glide is that during the glide phases, you can let the engine idle or shut off, avoiding pumping losses. DFCO is 100% pumping losses, so you're likely saving no gas.
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Old 08-13-2017, 10:34 AM   #3 (permalink)
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Dfco ?isn't it spinning the engine still? Helping you to slow,also known as compression braking. Just without any fule, so more effective at slowing. Witch burns more fule accelerating more often to makeup more lost speed ,or Neutral coating.
I dont have the feature so dont have a full understanding of its functionally. Ill ask a different way, does your glyd last longer in N or DFCO?
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Old 08-13-2017, 11:13 AM   #4 (permalink)
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A glide lasts longer than a DFCO, but we are talking very short glides here. I would be in and out of gear or clutch down and clutch up so often that the trip would be uncomfortable and hard work. And as I won't use engine off coasting the engine is burning fuel while in neutral anyway, so we are talking maybe 15 seconds at 300 mpg against 10 seconds at 9999 mpg.
When traffic is not an issue I use conventional Pulse and Glide, albeit with the engine running while I am coasting.
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Old 08-13-2017, 12:27 PM   #5 (permalink)
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If you're leaving it in gear, you can probably expect no, or even a negative effect.
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Old 08-13-2017, 12:43 PM   #6 (permalink)
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Since trying this I have recorded a 2% improvement in my fuel consumption for my usual weekend trip to Danderhall.
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Old 08-13-2017, 01:52 PM   #7 (permalink)
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Quote:
Originally Posted by JockoT View Post
Since trying this I have recorded a 2% improvement in my fuel consumption for my usual weekend trip to Danderhall.
That doesn't necessarily mean that your pulse and DFCO is the cause for improvement. 2% could easily come from traffic lights being kind to you or good weather.

Using DFCO keeps you from using gas while it's active, but also eats your speed. DFCO should almost exclusively be used when you're slowing anyway or trying to maintain speed going down hill.

You'll probably see better results applying a tiny bit of throttle for your glide to stay out of DFCO. You'll only use a tiny bit of fuel and should see much longer glides.
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Old 08-13-2017, 02:08 PM   #8 (permalink)
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Quote:
A glide lasts longer than a DFCO, but we are talking very short glides here. I would be in and out of gear or clutch down and clutch up so often that the trip would be uncomfortable and hard work. And as I won't use engine off coasting the engine is burning fuel while in neutral anyway, so we are talking maybe 15 seconds at 300 mpg against 10 seconds at 9999 mpg.
When traffic is not an issue I use conventional Pulse and Glide, albeit with the engine running while I am coasting.
You've got my intrigue

Sore leg from clutch fix. Learn to rpm matching. Only need the clutch for starting from a dead stop.

15sec /300 and 1sec 25mpg vs 10sec/999 and 1 sec/25
4 Vs 6 pulse/ mi
accelerating is the largest portion of fule consumption very evident in an all electric. Accelerating has a bigger impact than aero, this is why city suffers more than hwy.

Is that the big bump in the fuel log back in June? Looks like no trip log of pump to pump repeats. Fueling every two weeks will wash out the changes made in a weekly trip. For me it has been easyer to fule for my regular trip so that Its 200mi is an isolated test loop with a 30 mi warm-up. But thats my extra ordinary claims had to be backed up with extra ordinary testing on my truck. I would think that a steady vacuum pressure would probably yield better results IMHO.
What speed are 2200 and 2800 ?
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Old 08-13-2017, 03:16 PM   #9 (permalink)
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The big bump was the start of me starting to work on improving my fuel consumption. I use my Daily Trip from the ScanGauge for comparison. On like for like journeys.
The pump to pump figures vary because I seldom do the same type of journeys from one tank to the next.
My car accelerates at about 40 mpg but it takes a lot longer than a second to build the speed back up. Takes almost the same time to gain it as it did to lose it. I keep it in 5th and try to keep the throttle at less than 80%. It is only a 1200cc motor.
The speed varies from about 55 down to about 45.
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Old 08-13-2017, 08:05 PM   #10 (permalink)
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Remember, a OBD gauge is never going to be accurate to within 2%. The biggest thing that will throw it out is a change of driving style.

Pulse and DFCO doesn't work, even on cars like my Trafic (tiny diesel- heavy vehicle) where I can't even tell if I'm gliding in gear or neutral.

Pulse and gentle throttle may work. It works for Hybrids and it works for diesels, but I have feeling for a typical petrol car it may not - you're operating at max pumping losses that way - which is contrary to the whole point of P&G.

I don't bother with P&G on the highway - you'll have the same results just sitting in the slow lane.

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