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.

 

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

 

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.

 

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...

 

"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-economy/56857-does-make-sense-shift-neutral-during-driving.html

 

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.

 

Shifting to neutral has the following effects:

1) Preventing the ICE from turning on or off. Useful if going downhill and accelerating beyond 41mph, and you don't want to turn on the ICE.
2) Reducing energy drain

Neutral doesn't allow the car to go further, it goes a bit shorter due to the energy that isn't flowing to the motors.

 

I don't use neutral at >41 MPH, except to the extent I might shift into N at lower speeds on a downhill where speed can subsequently drift higher. (NOTE: Driving in neutral on a downgrade is illegal in many states.) If you shift into N at higher speeds, the ICE will run while in N. Better at those speeds is to deploy what some call warp stealth, which allows ICE shutdown. It is very similar to gliding, but is done at higher speeds. It is described here and in the link in my first post in this thread.

 

You might also take a look at the warm-up stages. Getting your car into S4 lets the vehicle engine cycle off at many opportunities that otherwise might be lost. Maddening, it often requires coming to a complete stop so the engine can 'shut off' and then you are in full hybrid mode.

My first 1-2 miles focuses on getting into S4 at the earliest opportunity. Thereafter, normal 1970s speed routes work pretty good.

One other technique is parking. In the winter, I see a nice, bright sunny area close to the parking lot exit. This lets me use battery power during the earliest 45 seconds to improve initial MPG and the sun is a pretty good space heater. In the winter, I'm parking in the shadiest possible place for battery longevity and AC avoidance.

Bob Wilson