Pulse and Glide for Dummies like me

[Laurel]

A while back nsteblay gave us excellent info on the pulse and glide i.e. this critical piece of info.  "The trick to increasing mileage as much as possible is to be in EV mode. I was attempting to stay in EV mode as I was accelerating from stops or slow traffic by babying the gas pedal. What I've discovered is if you accelerate to your desired speed quickly (hopefully the speed limit :)) and then totally let up on the gas EV will kick in. Immediately after EV kicks in resume pushing on the gas peddle being careful not to engage the gas engine again. I then glide as long as I can in EV mode. I repeat this process whenever necessary."

 

For us novices it is important to pay exact attention to the above paragraph.  I had read through it before I got my car and had a really false concept in my head.  Now that I have had my car for 4 days I understand what nsteblay means by pulse and glide.  I thought it meant accelerating, let up the gas until car goes into EV, and then coast and not apply any pressure.  If you screw it up like me and do that coasting, you immediately go out of EV.  You have to maintain steady gentle pressure on the gas pedal--not too soft or too hard and then you stay in EV.  So don't think glide means coasting.like I did. With the steady gentle pressure being oh so careful not to engage the engine then you stay in EV.  I can drop .4 L per 100 kilometers on one 100 kilometer trip  (or in American lingo an increase of 2 mpg gallon on a 60 mile trip) when doing it correctly.  So no coasting.  Probably you all knew that, but for me it was an epiphany to learn the steady gentle pressure technique.

Edited December 4, 2012 by Laurel

[roninsd]

Trying to stay in EV and getting the average MPG to inch up has become a driving game for me!  If I can get it up +.1 over the day before, it's a win!  Also, after 9 days, EV+ is engaging when I get home.  Fun!

[salprint]

Been averaging between 45-52 mpg on my 30 mile trip to work each day using that method.  For some reason I do better on the trip home.  Maybe the wind direction.

[darrelld]

A while back nsteblay gave us excellent info on the pulse and glide i.e. this critical piece of info. "The trick to increasing mileage as much as possible is to be in EV mode. I was attempting to stay in EV mode as I was accelerating from stops or slow traffic by babying the gas pedal. What I've discovered is if you accelerate to your desired speed quickly (hopefully the speed limit :)) and then totally let up on the gas EV will kick in. Immediately after EV kicks in resume pushing on the gas peddle being careful not to engage the gas engine again. I then glide as long as I can in EV mode. I repeat this process whenever necessary."

 

For us novices it is important to pay exact attention to the above paragraph. I had read through it before I got my car and had a really false concept in my head. Now that I have had my car for 4 days I understand what nsteblay means by pulse and glide. I thought it meant accelerating, let up the gas until car goes into EV, and then coast and not apply any pressure. If you screw it up like me and do that coasting, you immediately go out of EV. You have to maintain steady gentle pressure on the gas pedal--not too soft or too hard and then you stay in EV. So don't think glide means coasting.like I did. With the steady gentle pressure being oh so careful not to engage the engine then you stay in EV. I can drop .4 L per 100 kilometers on one 100 kilometer trip (or in American lingo an increase of 2 mpg gallon on a 60 mile trip) when doing it correctly. So no coasting. Probably you all knew that, but for me it was an epiphany to learn the steady gentle pressure technique.

You may already know this but selecting the Empower display option will give you the amount of max pedal application to remain in EV.

[Jus-A-CMax]

Wait, if you coast, doesn't that charge the battery anyway as it has an up arrow above the battery? I am finding that my CMax is rarely sustaining the speed at around 58-62 in EV mode as my battery is usually 1/3 to 1/2 to start with. Mind you, my odo is only 312 miles. So I've been using the coast rather than sustain the EV power cause it runs out like in 30 secods. Come to think of it, I don't think I ever seen a full battery charge in my CMax...am I missing something?

[Laurel]

You are not really supposed to have a fully charged battery because you want the electric motor to do as much work as possible--the internal programming tries to keep the battery at about half charge most of the time.  If you use the brake assist down a long hill you will see the battery charge up to almost 100% and it will use the electric motor until it gets down to the normal range and then it will alternate between electric and gas.  I found that with coasting versus sustained pressure I would only stay in EV for seconds as well.  That is when I started playing around with sustained pressure on the gas and I find I can stay in EV much much longer.  I only have about 300 kilometers on my car (180 miles).  I think that pulsing up to speed and then dropping back a wee bit and using sustained pressure works great--BUT it can be hard to stay in EV due to traffic, stop signs, etc.  I will be on a roll than some ass turns in front of me and I have to touch the brakes and start again<g>.

 

Page 104 in the owner's manual talks about maintaining the battery in the mid range.

Edited December 5, 2012 by Laurel

[ANDY]

Set SPEED CONTROL in eco mode. I use it where possible. It does a superioir job of feathering the throttle and keeping the drive in EV mode.

[RachelnLa]

Can you elaborate on that?

[Jus-A-CMax]

I am finding that sometimes I have to plain pulse and coast, no EV as theres not enough juice to sustain any meaningful EV. Anyone finding the same or are their batteries getting more efficient past the 1000 mile breakin? Mines at 580 right now.

[AgentCMAX]

For those interested...this article below talks about how to do P&G (Pulse and Glide) to improve fuel efficiency.  This if for the Prius II but I'm sure we can adapt the technique to the C-Max.  I haven't read the whole article yet but thought the folks here may want to get more mileage out of their C-Max.

 

http://www.cleanmpg.com/forums/showthread.php?t=1224

[Jus-A-CMax]

I've read that and its ubber confusing especially with all the Prius screens, which if I owned a Prius, I would try harder to understand but right now, it's a turn off. Someone should rewrite that or put a simple vid out on youtube to P&G with the CMax. I think I have the gist of it but I've tweaked it to coast cause I am finding the batteries are 1/3 low most of the time and the EV does not stay long at all so I need to recharge using the pulse, then letting it coast to regen the battery as much as possible.

[Fits2at]

So I'm starting to get the hang of the pulse and glide after 4 days of ownership. I too have a problem staying in EV when battery gets down to 1/3. I've had several trips that I got over 50 mpg and had one shorter trip that was 70+ mpg. Lifetime average is 35.5 and climbing!

[Jus-A-CMax]

Will the real CMaxP&G please stand up...

 

It seems there could be 2 variations of the P&G. As I see it and understand it, it revolves around whether to use the EV as part of the P&G or not. As well, the way our CMaxs work, some technique will regen the batteries in the Pulse phase or not. 

 

So heres what I understand thus far:

 

1. Utilize the EV. Pulse to 70 and let it glide down to 63 and then kick in EV and ride it out as much as possible until the battery drains to a point where it cannot sustain speeds to 58mph. Then pulse back to 70 and repeat.

 

The nuance here are in the pulse phase:

a) accelerate as fast as possible. Pros: get up to pulse speed ASAP Cons: no battery recharge so your EV glide is limited and becomes shorter and shorter as the batts do not get a decent amount of charge time as no braking.

b) steady but slow acceleration (keeping the up arrow over the battery in the pulse phase) to the end of the pulse speed. Pros: constant recharge Cons:more burn on the gas.

 

Which is better a) or b) - I honestly do not know yet. But to charge the batteries for the EV glide, I have to go with b) and sometimes I just use eco-cruise to recharge. Its a lot of work for sure.

 

 

2. Theres another variation of P&G where they talk of no even engaging the EV at all. Now, let me say, this could be formulated specifically for the Prius and they way that car shuts off the gas engine at some lower point. As I understand it and I've tried this once, you aim for an average speed of 67mph so you pulse up to 75 or 80mph and let it glide down to about 63mph. No EV at all so forgetaboutit.

 

I've had mixed results with one. One time I got 40.1MPG and another 31.3MPG. The 40.1 was a longer trip and warmer temps. That 31.3MPG was a shocker but me thinks I did not go over past 75mph peak. I wish it was more scientific but nope.

 

My question here to this forum's P&G expert - what is your technique or the P&G that you use?

[Tdefny]

It took me nearly a year to learn how to get the best mileage out of my Prius, because I tried too hard on Pulse driving, which was also a big thread at the time. It drove me crazy that my wife, who knew nothing of P&G, would always trounce me on MPG.

 

I eventually learned thet long gentle acceleration and mellow driving worked best - just like in any car. After that, I regularly got at or close to 50 MPG and 500 on a tank. That was Until I put different (non-LRR) tires and they reformulated the gas from MTBE to ethanol. After that MPGs dropped to around 42 and only if I nursed it.

 

This brings me to the other thread from 10years ago - "just drive it". You will probably enjoy the car more.

 

Having said that, my mileage in the C-max is also lower than I expected considering that 18-20 miles a day are plug-in. I may practice P&G after all. I will then watch my wife continue to get better mileage, as usual.

Edited December 31, 2012 by Tdefny

[MikeB]

I was trying to figure out why P&G works from a theoretical view, and think I have begun to understand it. The answer is that you want neither hard acceleration nor ultra-soft.

 

The engine has an efficiency map, and you're trying to place yourself in the most efficient range of that map. Why do I call it a map and not a curve? Because there are two input variables to play with: RPM and load. The output variable is, of course, efficiency, measured in fuel per kilowatt of output. The formal term for this map is Brake Specific Fuel Consumption, or BSFC.

 

Here's a sample of that map, though this isn't quite accurate for our Atkinson cycle engines:

http://en.wikipedia.org/wiki/File:Brake_specific_fuel_consumption.svg

 

The fancy eCVT we have is going to manage RPM, keeping our engine spinning at the optimal rate. But our use of the accelerator pedal is what drives the load. So, our real goal here is to commit to using the ICE some times, but commit to using it in the most efficient way possible, and to use electricity the rest of the time. Looking at the map, the numbers in the graph show fuel used per energy output, and we want the lowest fuel use. And the most efficient point on the map is on the upper middle, inside the circle labeled 206.

 

So what does that mean? Well, the RPM at that point is about 2200, medium low, but the load is rather high. If you punch it, asking the engine for all it can give, the computer will raise the RPM to meet the demand. So it looks like our goal is to put as much load on the engine as we can without pushing the RPM over about 2300. What does that translate to for your foot? Medium acceleration, neither soft nor heavy.

 

Ideally, our fancy dashboard would have a display of RPM and load on the same screen, or even better a BSFC gauge. But in the mean time, just accelerate moderately and then lift your foot.

 

 

 

[PWBarrett]

1. Utilize the EV. Pulse to 70 and let it glide down to 63 and then kick in EV and ride it out as much as possible until the battery drains to a point where it cannot sustain speeds to 58mph. Then pulse back to 70 and repeat.

 

I use P&G all the time around town since I'm starting and stopping anyway.  But it would never cross my mind to do that on the highway.  All that speed fluctuation is really going to piss off the drivers behind you.

[darrelld]

I was trying to figure out why P&G works from a theoretical view, and think I have begun to understand it. The answer is that you want neither hard acceleration nor ultra-soft.

 

The engine has an efficiency map, and you're trying to place yourself in the most efficient range of that map. Why do I call it a map and not a curve? Because there are two input variables to play with: RPM and load. The output variable is, of course, efficiency, measured in fuel per kilowatt of output. The formal term for this map is Brake Specific Fuel Consumption, or BSFC.

 

Here's a sample of that map, though this isn't quite accurate for our Atkinson cycle engines:

http://en.wikipedia.org/wiki/File:Brake_specific_fuel_consumption.svg

 

The fancy eCVT we have is going to manage RPM, keeping our engine spinning at the optimal rate. But our use of the accelerator pedal is what drives the load. So, our real goal here is to commit to using the ICE some times, but commit to using it in the most efficient way possible, and to use electricity the rest of the time. Looking at the map, the numbers in the graph show fuel used per energy output, and we want the lowest fuel use. And the most efficient point on the map is on the upper middle, inside the circle labeled 206.

 

So what does that mean? Well, the RPM at that point is about 2200, medium low, but the load is rather high. If you punch it, asking the engine for all it can give, the computer will raise the RPM to meet the demand. So it looks like our goal is to put as much load on the engine as we can without pushing the RPM over about 2300. What does that translate to for your foot? Medium acceleration, neither soft nor heavy.

 

Ideally, our fancy dashboard would have a display of RPM and load on the same screen, or even better a BSFC gauge. But in the mean time, just accelerate moderately and then lift your foot.

 

Have you tried configuring a MyView screen with those parameters?

[ptjones]

Buy a ScanGuage and you will have  that info all time.

[MikeB]

Have you tried configuring a MyView screen with those parameters?

In MyView, I can get a tach on the left, or engine output in kW on the left, but can't put either one on the right. So they are, in effect, mutually exclusive.

[F8L]

I have mastered pulse & glide in my Prius and from what I have learned to be most effective are these points:

 

---Keep acceleration near peak BSFC (figure out what RPM and load this is for the CMAX). For my car 1,500-1,600RPM was best.

 

---After entering a glide, reduce throttle input such that you are barely using EV power. This helps conserve battery energy and reduces overall energy expenditures. Don't try to drive around on EV power just to make your glide longer or you'll drain the battery and pay for it with reduced engine efficiency. There is no free lunch here.

 

---Pulse & glide generally doesn't work on the freeway. You'll annoy the hell out of everyone on the road. Better to just pick a speed and drive. ;)

 

---These may or may not be helpful tips but as you are learning what works best for your car these may lead you to other revelations. ;)

 

Ohh, does the CMAX have a consumption over time screen? Something that shows a graph of mpg over the last 30min or so? That could be very helpful in determining the effectiveness of your pulse & glide technique.

Edited January 17, 2013 by F8l

[ptjones]

In MyView, I can get a tach on the left, or engine output in kW on the left, but can't put either one on the right. So they are, in effect, mutually exclusive.

You need a ScanGauge then you have it all.

 

I have mastered pulse & glide in my Prius and from what I have learned to be most effective are these points:

 

---Keep acceleration near peak BSFC (figure out what RPM and load this is for the CMAX). For my car 1,500-1,600RPM was best.

 

---After entering a glide, reduce throttle input such that you are barely using EV power. This helps conserve battery energy and reduces overall energy expenditures. Don't try to drive around on EV power just to make your glide longer or you'll drain the battery and pay for it with reduced engine efficiency. There is no free lunch here.

 

---Pulse & glide generally doesn't work on the freeway. You'll annoy the hell out of everyone on the road. Better to just pick a speed and drive. ;)

 

---These may or may not be helpful tips but as you are learning what works best for your car these may lead you to other revelations. ;)

 

Ohh, does the CMAX have a consumption over time screen? Something that shows a graph of mpg over the last 30min or so? That could be very helpful in determining the effectiveness of your pulse & glide technique.

You would have to drive a CMAX to see how different it is. I've had 2 Escape Hybrids and driven my daughters 2011 Prius. I think the difference is the Lithium-ion battery with twice the range  and the aggressive  charging.   The car feels  different to drive and takes some getting use to. I have been able to pulse to 65mph and glide to 60mph and back up to 65mph without causing any problems. Keep in mind that I can go 63mph in EV and have about twice the battery range of Prius which changes the game.

[MikeB]

Ohh, does the CMAX have a consumption over time screen? Something that shows a graph of mpg over the last 30min or so? That could be very helpful in determining the effectiveness of your pulse & glide technique.

There is a simple bar graph, under the Fuel Economy section of the left dash panel. But it lumps things into 1, 2 or 5 minute blocks, and shows the last 5 blocks. I have mine set to 2 min blocks, and find it somewhat useful.

[F8L]

You need a ScanGauge then you have it all.

 

 

You would have to drive a CMAX to see how different it is. I've had 2 Escape Hybrids and driven my daughters 2011 Prius. I think the difference is the Lithium-ion battery with twice the range  and the aggressive  charging.   The car feels  different to drive and takes some getting use to. I have been able to pulse to 65mph and glide to 60mph and back up to 65mph without causing any problems. Keep in mind that I can go 63mph in EV and have about twice the battery range of Prius which changes the game.

 

Do those super short glides help overall FE for that trip vs. steady state driving?

 

In general, for a pulse & glide session to really be productive you have to glide much further than you pulse. On average I try to glide at least twice the distance I traveled during the pulse phase. For easy math: if I pulse for 1/2mile at 30mpg then glide for 1/2mile at infinite mpg I got 60mpg for that 1mile. That is hardly worth my time because I could do 60mpg just driving steady state in such conditions. Now if I pulse for 1/4mile and glide for 3/4mile i get 90+mpg. There are lots of variables and I am sure the CMAX is different but I doubt that the size of the battery is going to change the basics. You want to use as little energy as possible. EV energy is not free. :)

[DozerBob]

50+ MPG the easy way! After almost 3 weeks of 120 mile round trips to work I'm happy to report a consistent 50+ mpg, without the plugin feature. That's right, using EV-Later mode! On the freeways of Los Angeles and Orange County.  I'll try to explain how and why this works.

This first picture shows me at the start of my drive with battery capacity at 28 miles

I've got 28 mi Electric to use if I want and am at 1983.4 total miles on the car.

     When I got in my car after charging all night it read 25 miles, but after driving down a short hill it regenerated to 28. I switched to EV-later after taking the picture and left it there for the whole trip to work.

Here are my thoughts to consider.

1. I want to get the best gas mileage I can possibly get.

      Running on Electricity gives me the best mileage possible, therefore during this drive I'm going to try to travel as far as I can on Electricity especially when the  electric motor is the most efficient.

      The Electric motor is not very efficient going uphill. It takes more juice to push this car uphill due to its weight.

2. The gas engine gets bad gas mileage, but it can accelerate you uphills and increase your speed and charge your battery. 3 good things. What you don't want to do is cruise on the gas engine. I don't let it run for more than 1 minute at a time, If I can help it. You have the control. It's in your right foot. Use the Empower mode Display and your right foot to control the throttle. Don't use cruise control.

 

I'm going to call this technique, "Surfing". Just like in surfing, You use the waves to propel you. You will be using the waves, or small hills to decide when to use the ICE and when to go EV-Auto and "surf" down the hills.

 

 

      Get the car up to 62 and back off the throttle until the blue threshold comes on. Then don't let the center of the bold blue performance indicator get past it so as to stay in electric mode, easing off the throttle a bit as the Threshold Indicator slowly comes down. When I've slowed to 55 or so, I step on the accelerator and increase my speed, taking about 30 seconds to a minute to get back to 68. That way I've given the ICE time to charge the hybrid battery back up so when I go to electric mode, the Threshold indicator will stay at about the second line on the KW indicator longer. That's what I do on flat stretches of road.

       Highways in the cities are not flat. There are undulations in the terrain caused by overpasses and underpasses, They are called "vertical curves" and are the result of elevation changes. Overpasses are usually a mile or so apart as they cross over roads below. Sometimes the freeway will go underneath a road and you will descend in elevation to go underneath a bridge.  

        Now Here's the "Surfing" trick, try to eyeball the road ahead so that you are at the top of an overpass when you are at 68 and you are backing off the throttle to go into electric mode. The electric motor is more efficient going downhill, even slightly and you can maintain your speed longer because it takes less KW or juice to go downhill. The C-Max is a heavy car and it's own mass going downhill is a big plus. The longer you can run the electric motor, the higher your mpg will be simply because electric mpg is way higher than using the ICE. That is the crux of getting higher mpg. At the end of your trip you should see a definite increase in the percentage of EV-Mode used.

      Now if you see the road ahead is going uphill for an overpass, time it so you are firing up the ICE to propel you uphill and increasing your speed to the top.

If all you do is run the gas engine from the bottom of the hill to the top, and go electric from the tops down you will increase your mileage.

I ran 63.6 miles total 32.6EV and got 50.2 mpge in EV-Later mode

The 28 miles on the battery indicator was reduced to 24 even though I was in EV-Later the whole way.

Edited March 2, 2013 by DozerBob