New Prius Driver - Asking for Help with Technique

[Matt Herring]

Hey guys,

Just purchased my 2009 Prius base yesterday and will pick it up on Tuesday. I've been doing alot of reading and video watching online trying to educate myself about the best ways to max out a Prius on mpg. Alot of the suggestions are easy ones that transfer from my old car to the Prius but I did have a couple questions about hypermiling in the Prius that may differ from a non-hybrid.

Here's a couple I found online but wasn't sure if they are completely correct...

Thanks for all the help!

*** Gliding (least aggressive) – While traveling, remove foot from accelerator. Then, ever so slightly, re-apply pressure until all arrows disappear from the Energy screen. You'll a feel slight surge forward. This technique will only work when the car is warmed up.
You can glide at any speed, but it's difficult to get the arrows to disappear at speeds higher than 40 mph. At the higher speeds, even if you are gliding, the internal combustion engine will spin in order to protect the smaller electric motor from getting damaged. Above 40 mph, the engine is spinning but no gas is being used. Under 40 mph, the gas engine is not spinning. (Some Prius drivers report a "sweet spot" at 39 mph.)

*** Idle versus Shutdown
If you need to remain stationary for no more than ten minutes or so—stopping to run quickly into your house or pick somebody up—place the Prius into park, but don't shut down.
Turn off the heating, cooling, lights, and other electric accessories. Push the "Park" button.
The goal is to avoid shutting down and restarting, at which time the Prius will run through a startup cycle that uses gas.

[NeilBlanchard]

Hi Matt,

You should try to use the B (brake) setting on the shifter to slow the car, or use light brakes, to gain regenerative energy to charge the batteries. If you use the brakes too hard, then it uses the mechanical (conventional) brakes and you don't gain back as much energy.

For coasting where you want to carry speed, just shift into neutral.

I found that using the heat (and would assume the A/C) caused the engine to run a lot more, at the beginning of a drive. If you wait until it warms up on it's own, then a little heat can be had without a noticeable affect on the mileage.

I drove my Mom's 2005 Prius and I did not find a way to calibrate the dashboard mileage gauge, and it was way too optimistic (by 10-20%?). If you have a SGII, you may still want to use it.

I found it pretty easy to ecodrive, after driving my standard shift xA -- I got 52.5 and 53.4 on two tanks. (The dash gauge indicated over 60mpg for much of this...)

[PaleMelanesian]

On coasting, do the Glide procedure first before shifting to N. If you just go straight into N, the ICE may not shut down. If you do the gas pedal trick to get no arrows on the display, then you're gliding. ONce you're gliding, you can either hold that pedal position or shift to N.

I lost several MPG in a competition by missing that on a couple glides.

[Matt Herring]

Thanks for the info Neil! This will take some time to find optimum driving style but I'm excited to tackle the challenge (especially with warmer weather on the way). I still plan to use my SGII in the Prius so that should move my progress along a little quicker than without instrumentation.

Some of the vids I watched on YouTube said 30 mph is the best speed for a Prius to maximize mpg. I even saw a guy set his cruise at 30mph and get 99.9 mpg readout on the energy screen until the gas motor kicked in and he still got 60 mpg on the readout. Interested to see what the SGII says about that. Alot of talk online about using the cruise at 39mph or below (if possible) to maximize mpg...seems so counter-logic to driving in my former 4runner...not sure what to believe until I'm able to test it in the car.

[Matt Herring]

Great info. Pale! Thanks! I test drove a Prius the other day and went about 5 miles on pretty hilly terrain and didn't get the numbers I thought I would (about 44 mpg with the stock car off the lot) but I also just coasted in neutral without tapping the pedal after starting coast to get into the "dead band."

[PaleMelanesian]

For the very best information specific to the prius, I have to recommend the articles at cleanmpg.

Doing a low-speed pulse&glide - pulse at 20-25 mpg up to 30 mph or so, glide down to below 10 - should get you above 100 mpg.

Once the warmup hit is past. You have to hit 157F water temp (I think), and then at a stop allow it to auto-stop the engine. After that, everything will be running in top form. It cripples some of the functions before that, in the interest of faster warmup. That's why you want to leave it powered up instead of a full shutdown for a quick stop. It'll go through the whole warmup process again, including the forced 1-minute engine-on at first startup.

[Matt Herring]

I drive an 11 mile commute to work (mostly 35-45 mph roads...small hills along the way). I'm guessing moderate acceleration up the hills before disengaging the ICE and shifting into neutral is the way to go. My former 4runner was a v6 so the v4 Prius might need more aggressive pedal to stay at or near speed before cresting the hills.

If the 39 mph sweet spot is true (will confirm with SGII) then the first 5 miles of my trip on 45 mph roads should yield some good results (and maybe some angry drivers behind me)!

When I purchased my 4runner 2 years ago I went against my prior logic (drive it until it won't drive any more to get the loan out of the way and live off no car payment for awhile) because I knew I would be in a Prius before the 5 year loan was paid off. I imagine (barring horrific accident) that I will be in this Prius for the length of the 5 year loan and beyond.

[orange4boy]

Hey Matt,

Do you use your EBH religiously? I was wondering what was the max temp they get the coolant up to.

I'm experimenting with transaxle preheat and was wondering about the effectiveness of the different options for the engine.

Thanks.

[squatch81]

Originally Posted by PaleMelanesian

On coasting, do the Glide procedure first before shifting to N. If you just go straight into N, the ICE may not shut down. If you do the gas pedal trick to get no arrows on the display, then you're gliding. ONce you're gliding, you can either hold that pedal position or shift to N.

I lost several MPG in a competition by missing that on a couple glides.

I never shift into neutral when gliding - I utilize the decel mode on the cruise control on my '02 Prius. By hitting the decel every 3 - 5 seconds I glide a half mile while slowing from 55 to 25, then use regen to slow down to a near stop. I only use the brakes for the last car length or two.
I have to agree about the inaccuracy of the OEM MPG gauge. Mine usually reads 5 to 10% higher than actual.
The car does hold up well. It had 40,000 miles on it when I bought it in '04. Now it has over 120,000 on it with the only non-maintenance part replaced was a computer replaced under warranty at about 80,000 miles.

[Matt Herring]

Orange: I wish I could say I use my EBH religiously but I don't. I can only plug in at work and it's a timely set up. I'm probably using my EBH about twice a week right now when I could be doing it 5-6 times a week.

When I do use the EBH the mpg gains are substantial and recordable. In 20-30 degree temps I usually see about 120 degrees F on my SGII at start up which then drops down to about 90 degrees F within the first 1/4 mile...this is typical when using an EBH. From there engine temps rapidly increase and I'm at 150 degrees F within 1-1.5 miles of my 11 mile commute home. Comparatively, without using the EBH I'm at 150 degrees F at about the 3 mile mark.

With the EBH in 20-30 degree temps I can usually pull at 50+ mpg bar in the first 5 minutes of operation. Without the EBH in the same temps I routinely see 25-30 mpg in those first 5 minutes. Over 11 miles on my way home this difference is usually about .3-.5 mpg for the trip for me when using EBH vs. not using EBH depending on how well I hypermile the rest of the way home after the engine is up to EV-friendly temps.


Squatch: I do quite a bit of neutral shifting when gliding...especially when going down hill. I pulse to the top of the hill and put it in neutral just before 41 mph which results in ICE staying off when the car goes above 41 mph on the down hill glide. If you were to do the same process and not go into neutral on the down hill the ICE will kick in when it goes above 41 mph...plus you are rapidly slowing the car due to engine braking.

If we're talking about flat driving surfaces for long distances...I also rarely use neutral coast.

Personally, I would not recommend using neutral coast in high mph areas as neutral coasting at 58+ mph speeds is said to potentially damage the MG1 due to possible overs pinning (this is a theory that many Prius drivers adhere to however it has been disputed by many other Prius drivers as to any damage it may cause...for me I error on the side of caution).

For highway driving I utilize the GPS & IGN X Guages on my SGII (the new Super Highway Mode way of driving...GPS is a finer measurement of throttle position or TPS on the SGII). On a 55 mph highway, pulse up to 60 mph and then slowly back off the GO pedal until GPS is in the 8-18 range (depending on SOC this varies as low SOC will only allow around 8-9 GPS and high SOC will allow 10-18 GPS before tripping the ICE). When backing off the GO pedal you can settle the GPS number around 8-12 and you will see IGN go from 10+ down to 5 where it will stay unless you trip the ICE by making GPS go too high. At this point you can continue in 5 IGN with feather pressure on the GO pedal (keeping GPS in the 8-12 range) and continue to benefit from light acceleration of the car while mph winds down from 60 mph to 45-50 mph when you then can repeat the process over and over.

This basically gives you a small amount of continued acceleration which retards the deceleration process of normal pulse and glide.

I like your cruise control process...I just don't have cruise in my Prius to try it out. What kind of mpg are you seeing in typical highway travel?