Pulse and Glide Technique Details

ZooPrius · 01-15-2009, 01:43 AM

I am only one month into Prius ownership and I am working on hypermiling. I realize it isn't really going to happen right now since it is -5 degrees outside, we have about 3 feet of snow on the ground and most of the roads have packed snow an inch or two deep. Still this week I am getting about 40 mpg more like 55 if you don't count the first 5 minutes of each drive. Most of my driving is 10-15 minutes on 35 mile an hour roads with some small rolling hills. I have a partial grill block using pipe insulation I learned about here. I have not gone for the EBH yet. There are too many environmental variables for me to do a trial and error method to learn how to do this for the next few months.

I see people mention pulse and glide but I was hoping some of the hypermilers could give me some details:

1. Are the pulses using the ICE or do you use the elective motor for this too?

2. Do you use electric only for some of the pulses?

3. How long are the pulses? Am I better off just trying to get back up to speed limit as quickly as possible so I can glide sooner or trying to keep the acceleration down to avoid burning up so much gas on the pulse?

4. Is it better to pulse down a hill so I can roll up the other side or roll down the hill and pulse up the other side?

5. Lets sayyou are driving in a 45 zone level ground how low do you let your speed get before you pulse back up. In other words are you doing long pulses (20 seconds) and long intervals (30-60 seconds) or short pulses (2-5 seconds) and short intervals (15 seconds)?

6. On the glide part I notice the car glides better with my foot pushing down on the pedal just enough to eliminate all the arrows on the "energy screen". Is it better to glide this way without charging or will I just end up not having enough charge later on to drive in the electric mode.

Thanks

JimboK · 01-15-2009, 07:40 AM

1. Pulses are with the ICE only. You should execute them to avoid either low-power with electric only or high power with electric boost to the ICE. Whether pulsing or gliding it is more efficient to avoid pushing power to or pulling power from the battery.

2. No.

3. Acceleration rates should be at a rate that avoids pushing the ICE into inefficiently high RPM ranges. Without a tachometer, if you keep the instantaneous MPG at least half the vehicle speed you'll generally avoid those ranges. Beyond that, since I generally drive in at least moderate traffic, I continually adjust pulse duration (and rate, to some degree) to stay safe and balance fuel economy and courtesy.

4. Depends on the hill. On most hills I glide down and pulse up the other side. On a gentle downhill I might begin my pulse before hitting the nadir to help gain a little momentum for the climb.

5. Again, much of that is guided by traffic. In a 45-MPH speed zone with moderate to heavy traffic, I generally don't P&G anyway. P&G is done at <40 MPH, and to be riding at, say, 30 MPH likely is unsafe. Even in light traffic, I might choose not to P&G. If following traffic can't pass (i.e., a two-lane road) or they might quickly approach me around a blind curve or hill, I'll stay close to posted speed limits. Instead, I seek alternative routes with lower speed limits or lighter traffic that offer more P&G opportunities.

6. You've nailed it. That is the most common glide technique, and mastering it will go a long way to optimizing fuel economy.

Finally, see this for perhaps the most complete discussion of P&G.

krousdb · 01-15-2009, 09:29 AM

Or see this:
Toyota.com : Hybrid Synergy View : 2005 : Fall : Prius Marathoners Top 100 mpg

Bob64 · 01-18-2009, 05:27 AM

1. Are the pulses using the ICE or do you use the elective motor for this too?
Thats a trick question. They're both combined such that its impossible to use the ICE without the electric motor. However, I believe you meant: Do you pulse with pure gas power (ICE) or with a mix of gas (ICE) and power coming from the battery (powering the electric motors)? The answer to that is: as much pure gas power as possible (ICE only) and as little use of the battery as possible.

2. Do you use electric only for some of the pulses?
Avoid (at almost all costs) if possible.

3. How long are the pulses? Am I better off just trying to get back up to speed limit as quickly as possible so I can glide sooner or trying to keep the acceleration down to avoid burning up so much gas on the pulse?
Depends on who is tailgating you (if any) and what the speed limit is. If theres no one tailgating me, I pulse to a speed that I feel will get me to point B fast enough while sticking as close to the "optimal speed" of 22mph. You may have to maintain speed at the speed limit if you have a tailgater. As for how "fast" you accelerate, try to stick between 1400rpm and 1800rpm.

4. Is it better to pulse down a hill so I can roll up the other side or roll down the hill and pulse up the other side?
Depends on the hill and the speed limit. Its better to go down a hill as slow as possible WITHOUT hitting the brakes or regenerating (others may have differing opinions about this bit). If your hill causes you to accelerate above 41mph, shift into neutral before u hit 41, to prevent the ICE from spinning. Do not go above ~65mph in neutral with the ICE off (may overspin the motors... but the limit is debatable)

5. Lets sayyou are driving in a 45 zone level ground how low do you let your speed get before you pulse back up. In other words are you doing long pulses (20 seconds) and long intervals (30-60 seconds) or short pulses (2-5 seconds) and short intervals (15 seconds)?
As slow as I can go without pissing off the traffic behind me. Typically long pulses and long intervals between pulses, depending on traffic ahead of me. It is my opinion that the length of pulses doesn't matter as much as avoiding braking. Even if you do perfect pulses, all that effort will be wasted if you misjudge the slowdown ahead and waste 20mph of built-up speed.

6. On the glide part I notice the car glides better with my foot pushing down on the pedal just enough to eliminate all the arrows on the "energy screen". Is it better to glide this way without charging or will I just end up not having enough charge later on to drive in the electric mode.

Charging isn't gliding. If your charging, your "coasting". If your hard-core, I'd recommend shifting into neutral once your sure the ICE is off, just to reduce idle electric draw from the inverter/motors. Be sure to shift back into drive BEFORE you hit the brakes (neutral disables regeneration)!! You don't want to drive in the electric mode.

dominicsavio · 01-20-2009, 01:01 AM

One more thing ZooPrius- patience and practice. It's also what I am learning. You're already at 40 mpg in very cold conditions so you've got to be doing many things right. Many people drive for a year or two before nailing this...

dominicsavio · 01-20-2009, 01:10 AM

"If your hard-core, I'd recommend shifting into neutral once your sure the ICE is off, just to reduce idle electric draw from the inverter/motors. Be sure to shift back into drive BEFORE you hit the brakes (neutral disables regeneration)!! You don't want to drive in the electric mode. ?"

Bob - whats the best approach when shifting to N while driving? and Why do you shift to N? I guess because shifting to N allows the car to go further quicker because of 'extra' momentum arising from the 'free flow' which would not otherwise occur when the car is engaged in CVT (regardless of whether you are gliding or not)?

I'd really like to get a take on this from people who do this...

Check out this post also for some discussion on this http://priuschat.com/forums/fuel-eco...g-driving.html

HTMLSpinnr · 01-20-2009, 01:19 AM

Shifting to N gives the same effect has finding the accelerator sweet spot w/ no energy in or out. Downside is, there's no powertrain management for ICE control above 42mph (or so the debate goes on), so I'd only do it personally at lower speeds.

JimboK · 01-20-2009, 10:14 AM

Quote:

Originally Posted by HTMLSpinnr

Shifting to N gives the same effect has finding the accelerator sweet spot w/ no energy in or out.

Well, pretty close. There actually are very small differences in current flow and drag between the two techniques. See this for more. Fuel economy is very similar, so for the average P&G'er it probably doesn't matter.

ZooPrius · 01-20-2009, 07:13 PM

Thanks for the advice. I drove to the auto show this weekend about 135 miles and got 53 mpg using most of these techniques. It was nice to see the little tank go that far. I also noticed how much drafting off a truck can help. I had previously thought it was insignificant but with the instant feedback I can see it is not especially on level ground or a slightly downward gradient.

I did not know about the shifting into neutral thing since that discussion was posted after my trip. Since this was a lot more highway driving than city and more than I had done in one trip in over a month the techniques are definitely different. At highway speeds I had a very hard time getting the "sweet spot". I found it only for a few seconds. Is this what is supposed to happen? Is this why some of you are using neutral?

Thanks

ZooPrius · 01-20-2009, 07:16 PM

Quote:

Originally Posted by HTMLSpinnr

...there's no powertrain management for ICE control above 42mph

What does this mean? Don't we want the power train disconnected for rolling purposes or is that a problem at higher speeds?

01-15-2009, 01:43 AM	#1
ZooPrius Junior Member Join Date: Jan 2009 Location: Kalamazoo, MI Posts: 7 My Car: 2004 Prius Model: Package: #2 Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Pulse and Glide Technique Details I am only one month into Prius ownership and I am working on hypermiling. I realize it isn't really going to happen right now since it is -5 degrees outside, we have about 3 feet of snow on the ground and most of the roads have packed snow an inch or two deep. Still this week I am getting about 40 mpg more like 55 if you don't count the first 5 minutes of each drive. Most of my driving is 10-15 minutes on 35 mile an hour roads with some small rolling hills. I have a partial grill block using pipe insulation I learned about here. I have not gone for the EBH yet. There are too many environmental variables for me to do a trial and error method to learn how to do this for the next few months. I see people mention pulse and glide but I was hoping some of the hypermilers could give me some details: 1. Are the pulses using the ICE or do you use the elective motor for this too? 2. Do you use electric only for some of the pulses? 3. How long are the pulses? Am I better off just trying to get back up to speed limit as quickly as possible so I can glide sooner or trying to keep the acceleration down to avoid burning up so much gas on the pulse? 4. Is it better to pulse down a hill so I can roll up the other side or roll down the hill and pulse up the other side? 5. Lets sayyou are driving in a 45 zone level ground how low do you let your speed get before you pulse back up. In other words are you doing long pulses (20 seconds) and long intervals (30-60 seconds) or short pulses (2-5 seconds) and short intervals (15 seconds)? 6. On the glide part I notice the car glides better with my foot pushing down on the pedal just enough to eliminate all the arrows on the "energy screen". Is it better to glide this way without charging or will I just end up not having enough charge later on to drive in the electric mode. Thanks

01-15-2009, 07:40 AM	#2
JimboK One owner, low mileage Join Date: May 2006 Location: Chesterfield, VA Posts: 2,553 My Car: 2005 Prius Model: Package: #2 Thanks: 4 Thanked 99 Times in 72 Posts Friends: 6	Re: Pulse and Glide Technique Details 1. Pulses are with the ICE only. You should execute them to avoid either low-power with electric only or high power with electric boost to the ICE. Whether pulsing or gliding it is more efficient to avoid pushing power to or pulling power from the battery. 2. No. 3. Acceleration rates should be at a rate that avoids pushing the ICE into inefficiently high RPM ranges. Without a tachometer, if you keep the instantaneous MPG at least half the vehicle speed you'll generally avoid those ranges. Beyond that, since I generally drive in at least moderate traffic, I continually adjust pulse duration (and rate, to some degree) to stay safe and balance fuel economy and courtesy. 4. Depends on the hill. On most hills I glide down and pulse up the other side. On a gentle downhill I might begin my pulse before hitting the nadir to help gain a little momentum for the climb. 5. Again, much of that is guided by traffic. In a 45-MPH speed zone with moderate to heavy traffic, I generally don't P&G anyway. P&G is done at <40 MPH, and to be riding at, say, 30 MPH likely is unsafe. Even in light traffic, I might choose not to P&G. If following traffic can't pass (i.e., a two-lane road) or they might quickly approach me around a blind curve or hill, I'll stay close to posted speed limits. Instead, I seek alternative routes with lower speed limits or lighter traffic that offer more P&G opportunities. 6. You've nailed it. That is the most common glide technique, and mastering it will go a long way to optimizing fuel economy. Finally, see this for perhaps the most complete discussion of P&G. __________________ Jim Click here for car details.

01-15-2009, 09:29 AM	#3
krousdb Senior Member Join Date: Jul 2005 Location: Raleigh, NC Posts: 405 My Car: 2004 Prius Model: I Package: #7 Thanks: 9 Thanked 297 Times in 185 Posts Friends: 10	Re: Pulse and Glide Technique Details Or see this: Toyota.com : Hybrid Synergy View : 2005 : Fall : Prius Marathoners Top 100 mpg

01-18-2009, 05:27 AM	#4
Bob64 Sapphire of the Blue Sky Join Date: Apr 2007 Location: Virginia Posts: 1,135 My Car: 2007 Prius Model: N/A Package: #2 Thanks: 3 Thanked 9 Times in 9 Posts Friends: 0	Re: Pulse and Glide Technique Details 1. Are the pulses using the ICE or do you use the elective motor for this too? Thats a trick question. They're both combined such that its impossible to use the ICE without the electric motor. However, I believe you meant: Do you pulse with pure gas power (ICE) or with a mix of gas (ICE) and power coming from the battery (powering the electric motors)? The answer to that is: as much pure gas power as possible (ICE only) and as little use of the battery as possible. 2. Do you use electric only for some of the pulses? Avoid (at almost all costs) if possible. 3. How long are the pulses? Am I better off just trying to get back up to speed limit as quickly as possible so I can glide sooner or trying to keep the acceleration down to avoid burning up so much gas on the pulse? Depends on who is tailgating you (if any) and what the speed limit is. If theres no one tailgating me, I pulse to a speed that I feel will get me to point B fast enough while sticking as close to the "optimal speed" of 22mph. You may have to maintain speed at the speed limit if you have a tailgater. As for how "fast" you accelerate, try to stick between 1400rpm and 1800rpm. 4. Is it better to pulse down a hill so I can roll up the other side or roll down the hill and pulse up the other side? Depends on the hill and the speed limit. Its better to go down a hill as slow as possible WITHOUT hitting the brakes or regenerating (others may have differing opinions about this bit). If your hill causes you to accelerate above 41mph, shift into neutral before u hit 41, to prevent the ICE from spinning. Do not go above ~65mph in neutral with the ICE off (may overspin the motors... but the limit is debatable) 5. Lets sayyou are driving in a 45 zone level ground how low do you let your speed get before you pulse back up. In other words are you doing long pulses (20 seconds) and long intervals (30-60 seconds) or short pulses (2-5 seconds) and short intervals (15 seconds)? As slow as I can go without pissing off the traffic behind me. Typically long pulses and long intervals between pulses, depending on traffic ahead of me. It is my opinion that the length of pulses doesn't matter as much as avoiding braking. Even if you do perfect pulses, all that effort will be wasted if you misjudge the slowdown ahead and waste 20mph of built-up speed. 6. On the glide part I notice the car glides better with my foot pushing down on the pedal just enough to eliminate all the arrows on the "energy screen". Is it better to glide this way without charging or will I just end up not having enough charge later on to drive in the electric mode. Charging isn't gliding. If your charging, your "coasting". If your hard-core, I'd recommend shifting into neutral once your sure the ICE is off, just to reduce idle electric draw from the inverter/motors. Be sure to shift back into drive BEFORE you hit the brakes (neutral disables regeneration)!! You don't want to drive in the electric mode. __________________ 2007 "Pirates of the Internet" Seaside Pearl Nicknamed "Souten" (蒼天) Japanese for Blue Sky. Named for the hope that its namesake will remain forever the same color as its exterior. Lifetime average MPG at 30037 miles: 64.6MPG Daily trip (13 miles each way) mpg : 64.3MPG Personal mpg record driving the above trip: 90.5MPG @ 86F Mods: 90% grill block EBH "Racing" Hubcaps

01-20-2009, 01:01 AM	#5
dominicsavio Member Join Date: Oct 2008 Posts: 83 My Car: 2006 Prius Model: Package: #6 Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Re: Pulse and Glide Technique Details One more thing ZooPrius- patience and practice. It's also what I am learning. You're already at 40 mpg in very cold conditions so you've got to be doing many things right. Many people drive for a year or two before nailing this...

01-20-2009, 01:10 AM	#6
dominicsavio Member Join Date: Oct 2008 Posts: 83 My Car: 2006 Prius Model: Package: #6 Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Re: Pulse and Glide Technique Details "If your hard-core, I'd recommend shifting into neutral once your sure the ICE is off, just to reduce idle electric draw from the inverter/motors. Be sure to shift back into drive BEFORE you hit the brakes (neutral disables regeneration)!! You don't want to drive in the electric mode. ?" Bob - whats the best approach when shifting to N while driving? and Why do you shift to N? I guess because shifting to N allows the car to go further quicker because of 'extra' momentum arising from the 'free flow' which would not otherwise occur when the car is engaged in CVT (regardless of whether you are gliding or not)? I'd really like to get a take on this from people who do this... Check out this post also for some discussion on this http://priuschat.com/forums/fuel-eco...g-driving.html

01-20-2009, 01:19 AM	#7
HTMLSpinnr Gen III Forums Moderator Join Date: Dec 2003 Location: Surprise, AZ (Phoenix) Posts: 4,074 My Car: 2010 Prius Model: IV Package: Solar Roof Thanks: 216 Thanked 437 Times in 196 Posts Friends: 18	Re: Pulse and Glide Technique Details Shifting to N gives the same effect has finding the accelerator sweet spot w/ no energy in or out. Downside is, there's no powertrain management for ICE control above 42mph (or so the debate goes on), so I'd only do it personally at lower speeds.

01-20-2009, 07:13 PM	#9
ZooPrius Junior Member Join Date: Jan 2009 Location: Kalamazoo, MI Posts: 7 My Car: 2004 Prius Model: Package: #2 Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Re: Pulse and Glide Technique Details Thanks for the advice. I drove to the auto show this weekend about 135 miles and got 53 mpg using most of these techniques. It was nice to see the little tank go that far. I also noticed how much drafting off a truck can help. I had previously thought it was insignificant but with the instant feedback I can see it is not especially on level ground or a slightly downward gradient. I did not know about the shifting into neutral thing since that discussion was posted after my trip. Since this was a lot more highway driving than city and more than I had done in one trip in over a month the techniques are definitely different. At highway speeds I had a very hard time getting the "sweet spot". I found it only for a few seconds. Is this what is supposed to happen? Is this why some of you are using neutral? Thanks

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