How to Pulse and Glide with pictures...

Jim,

Thats what the SGII is great for. it tells me when I am in stealth and I can see when rpm drops and IGN goes to 14 or15.

 

Not theoretical, it just takes practice. If you have the luxury of driving when roads are clear, you can accelerate at different rates, and that'll either prevent or allow regen during acceleration back up to speed ... turning on your needs / the battery's needs. Also, if you (again, turning on posted speed limits & traffic) don't accelerate past 35mph as your top speed, you can get your average tank up to and past 70mpg pretty easy.

 

With this approach you are totally missing what a true glide is all about.
It's about (INFINITE) MPG, which is far different that the 99.9+ you may see when you lift your foot but are not actually gliding.
THe ability to Glide, gas free, is what sets the Prius apart from other cars, and if you don't understand and take advantage of that you are missing the icing on the cake. Average INFINITY into any number and see what happens, it jacks the average way up.
But to do it you have to know when a glide is able to be achieved. So that's why its a little more complicated.
The next in effieciency would be the stealth and warp stealth.

And the energy screen must be up for feedback.

 

A pulse can be any form of Prius motivation that moves you forward.
At any rate, by any means. ICE, Electric(stealth), both....
What yo do after that is what most important. The glide, or stealth or warp stealth
Sure purists can analyze the pulse that is most efficient, but what you do after you pulse is most important.

 

I'm confused then. I just read you want to not have anything going to the battery either direction when pulsing, so why use that term to describe the technique? To further muddy the water, the word "pulse" is often used in an electrical context:

The word "pulse" in the English language is never to my knowledge used to describe anything that could be considered slow (and writing "slow" in front of "pulse" is almost an oxymoron). The "pulse" in "pulse/glide" everyone is describing IS slow.

Can you see how this is confusing?

 

But is it? It's been posted here that the efficient pulse IS important to getting high mpg. Let's split hairs here. Are we talking 2 mpg or 8? Or are some people throwing monkey wrenches at us newbies getting us to worry about non-battery pulses?

 

Sure, I can understand the confusion. But remember P&G is just a term given to this driving technique. In it's original form the technique is kind of extreme and gets critisizm from a real world application stand point.
That is why I say the pulse is really anything that propels you forward, at whatever rate would be appropriate and efficient.
Pulses can be efficient or not......But, it's what you do after the pulse that counts the most. .
And knowing how and when to glide is of utmost importance. As is stealth and warp stealth.
I'll say it a million times....this is what sets the Prius apart from all other cars. Understand it. Exploit it.

A spacecraft uses pulse and glide. Burn the rocket a few seconds and glide millions of miles, the rest of the way.

 

I see what you're saying. I will read up in detail on the knowledge I am lacking with regard to this subject.

Before I changed out my Integrity tires to Comfortreds (huge mpg hit) I had gotten to the point where I was consistently getting 55-57 tanks using the Consumption Screen alone. I could have broken 60 just with the Consumption Screen and an engine block warmer. Could I get 65+ using the Energy Screen? Perhaps. Is it worth it to me for stress and safety reasons? No.

 

I understand what you're saying. Still I would prefer ICE/glide or crawl/glide for us newbies The use of the rocket example proves my point. The pulse of a rocket is a short burst designed to get the rocket quickly to the desired speed, not gradually over a longer period. The word "pulse" also connotes a shortness of time that is diametrically opposed to "pulsing" in the Prius world – especially in getting up to speed from a dead stop.

 

Thanks for this. I was pulsing a little too hard (mpg would be in the teens).

 

I agree that mastering the glide is the more important part of P&G, in large part because it takes more practice and precision.

I wouldn't say pulse method and rate don't matter. First, you don't want to pulse so slowly as to be running off electricity only; it will be painstaking slow for most. It won't last long; the Prius is not designed for sustained electric propulsion. Most importantly, ICE power eventually will be needed to replenish the charge. That's less efficient than using that power directly for propulsion.

Pushing the pedal too hard also is inefficient. As I suggested previously, it can push the ICE into inefficiently high ranges and likely invokes the electric motor for boost. So you're burning more gas than necessary to get up to speed and, like the electric-only scenario, still depleting the battery charge. Those who have done sustained climbs up mountains have seen the effects on the battery of a heavy foot (necessary in those cases).

That's why I suggest keeping iMPG at least half the vehicle speed during ICE-on periods. My experience and that of others demonstrate that that pretty consistently keeps ICE RPM below 2200-2400 (varying a little with speed) and keeps you out of the battery. From there, you actually do have a pretty wide range to play with, though I believe that for the most part, slower is better as long as the ICE stays on. These days I generally aim to pulse at an RPM of about 1500-1600, where iMPG is roughly equal to MPH. Last year at this time I was pulsing at about 2000-2400. I don't have data from a controlled test (yet), but the results I linked in my previous post here and those from many other drives this summer are, as a group, considerably better than results from last summer over the same routes.

 

I am completely confused about what screen to have up, Consumption or Energy. I have used 'Consumption' but I don't seem close to breaking the 50 + MPG barrier. It could be from traffic behind me pressing me to go faster at start ups or approaching stop lights. I have had drivers riding me from behind if I don't race to a red light. I believe I am very good at hypermiing but I still have City and Interstate drivers that get frustrated with my hypermiling techniques. When in slow traffic some of these drivers get very aggressive while others appreciate me 'gliding' slowly in stop and go traffic.
If I switch to the Energy screen would I better monitor the systems in use versus Consumption screen? I have been trying to master exactly what color conserves the best without draining the hybrid battery. It's almost like I need to have a navigator monitor all systems for best MPG's while I drive. BTW, I saw he Energy screen thread, its incredible. I plan to study the colors and directional arrows. I have no idea what RPM's I am going so keeping the car at or below a certain range, other than my ear and feel, doesn't seem possible. I didn't know the colors slightly change based on the car's acceleration, I really don't believe most Prius owners understand the complexities of this car.

 

I agree, I fail to see how the consumption screen is safer than the energy screen.

 

I just watch the mpg bar itself with my peripheral vision – I don't look at the mpg number readout below the bar.

If I were to use the Energy Screen arrows, it takes more attention. Pretty simple, really. You can't just monitor the arrows without actually looking at the screen for a 1-3 seconds while you adjust your pedal pressure, etc. It's just as dangerous as fumbling with audio settings in a vehicle without the steering wheel controls. A lot can happen in two seconds at 45 mph.

I would feel safer having the data from the Energy Screen more directly in my line of sight to the road. It is likely the mpg bar on the Consumption Screen is on the right side of the screen for the Japanese designers who thought it safer and/or easier to see in a RH drive vehicle.

 

I've achieved 57 mpg tanks using only the Consumption Screen, 40+ psi in the tires and no a/c (in the spring). But if you really want to hypermile and get 65+ mpg, read up on the in-depth techniques on Priuschat involving the Energy Screen.

 

I agree with every word. The pulse technique is important too.
That's why I stated this in a subsequent post. ....

When I say appropriate, it depends on the senario.
If I'm moving to the next short distance stoplight, I'll use and EVmode pulse.
If traveling forward with someone behind me I'll ICE pulse at a quicker rate, if not, a slower more efficient rate.
The pulse comes down to what's sensible and efficient, and every scenario is different.

 

OK, let's try to make this simple. Here are the rules:

1. Keep it on the Energy screen. I use the Consumption screen only to spot check my results via the five-minute bars.
2. During pulses, watch your instantaneous MPG and keep it at least half the vehicle speed. You're accelerating of course, so the relationship will constantly fluctuate. With a little practice you'll get a pretty good sense of a good acceleration rate, and then all you need to do is spot check the gauges to validate. Ignore the arrows and don't worry about RPM. Obviously you can't monitor RPM without add-on instrumentation. That's why I suggest watching the iMPG/MPH relationship; it's a suitable surrogate for this purpose for those without the instruments.
3. During glides, aim for the "no-arrows" condition shown in the first post. This takes a little practice to hit and hold, but it's not difficult once you get your foot "trained."

P&G is only one of many important tools in the box. To know when and how best to use it is just as important. Good hypermiling includes all the tools, using those that best fit the situation at the moment.

Anticipatory driving is critical -- knowing when best to begin and end a pulse based on traffic and terrain, learning the timing of red lights on your routes, watching for the lights and other slowdowns, and beginning a glide as soon as possible to the extent traffic behind will tolerate. The CleanMPG folks have coined the term DWB: driving without brakes. Every time you hit the brakes, you've wasted a little kinetic energy. Better is to let that energy go to work for you and allow the car to decelerate in the most efficient way possible for as long as possible -- i.e., gliding.

There is a balance on busy roads. On the one hand, I won't drive 20 MPH in a 35 MPH zone if heavy traffic has no chance to pass. My first guiding principle for hypermiling is to be safe, legal, and courteous. In heavy traffic, I often resign myself to just going with the flow. On the other hand, I won't give in to impatient tailgaters who insist through their actions that I drive 20 MPH over the limit and wait until the last minute to slam the brakes approaching a stop. A jerk will be a jerk, and I can't change that.

Route planning is important too. I seek out through mapping (Google maps) and experimentation which routes are favorable for P&G -- those with less traffic and lower speed limits. It could end up being a somewhat longer route, but I am careful to avoid a route that uses more total fuel. (I have a simple spreadsheet to calculate total fuel consumption.) Where I have a choice, I plan the time of my drives for periods of lighter traffic.

I should mention that even with a perfectly executed P&G, some conditions simply won't allow great fuel economy, including short trips that never allow the car to fully warm to efficient temperatures and lots of stop and go in weather extremes where cabin climate control is constantly running at high levels. There are tools and techniques that help with those conditions, but they're outside the scope of this thread.

You seem frustrated but genuinely interested in improving your fuel economy. I will restate the challenge I made elsewhere: Contact Wayne at CleanMPG for a hands-on clinic. There's nothing like seeing it firsthand and having a coach. Did you receive the PM I sent you about that?

[EDIT: There may be an issue here of terminology being confusing. "Gliding" as I describe in rule #3 is for speeds of 40 MPH and below. Many of us limit our use of the term "glide" to these lower speed scenarios, whereas "warp stealth" is used to describe similar (but not identical) ICE-off deceleration at higher speeds. The pedal-feathering technique is the same, but warp stealth is a little harder to hit and hold (especially if state of charge is low) and its value more limited. "Pulse and warp stealth" may not be the best strategy at higher speeds, depending on speed, terrain, and traffic.

This is Sandman's thread so he ultimately can make the call, but with the title of "How to Pulse and Glide with Pictures," I suggest focusing the discussion on "true" sub-41 MPH P&G to eliminate confusion. The subject of optimal highway fuel economy is more complex and there still is debate on best practices.]