Maximize MPG between Traffic lights using P&G

The Gen3 has more fuel efficient engine than the Gen2.
Also, The Gen3 engine has wider fuel efficient sweet area the the Gen2's, so Gen3 drivers don't have to stick with a certain rpm range for pulsing.

However, Gen3 is heavier than Gen2, therefore the MPG gain is not significant.

For more specific speed, there is the 46 mph threshold.
Prius acts completely different animal between below and above the threshold.
The real P&G can be done below 46 mph only.
I know the "warp-stealth" above 46 mph, but Prius has to spin the ICE in fuel cut mode and it consumes a certain amount of electric energy (a few kW) just for ICE spinning.
I have tried it, but the fuel gain was very limited and negligible.

Since then, I drive highway in constant speed using cruise control, because...

• sometimes, it is dangerous to drive at variable speed on highway. I have to watch vehicles behind me.
• in general, a highway driving is long, so I am relax using the CC than be stressful to control accelerator and watch monitors.
• It is more safe to watch traffic than to watch monitors.
• the stressful driving does not give me any significant MPG gain.

I think there is no magic method on highway driving.
Just, slower you drive, better MPG we'll see.

Ken@Japan

 

The major enemy on highway is air drag.
It is related to the square of the speed, so we see 1.4 times more drag at 65 mph than 55 mph.

Please refer to following chart for Gen2 (42 mph threshold).
It is based on the famous Wayne Brown's simulator which is well calibrated by his extensive field tests.

Ken@Japan

 

Nice data points, though there are many factors to consider. In the city with close spaced lights it usually is easiest to do a 1/3 pulse and 2/3 glide between lights. 1/4 pulse to 3/4 glide gives slightly more MPG but at the cost of speed toward the end of your glide-and the goodwill of those behind you.
Short highway just keep a steady foot at whatever speed gives the highest MPG on the useless MPG graph on the dash. As ken1784 says, cruise control is great as long as you have flat highway, otherwise use your foot.
Doing that I would expect you, if you pump up your tires a bunch, to break some mid 60 tanks during the summer.

Wayne

 

I believe you will see some improvement after 5000 miles odometer.

However, the big impact is ambient temperature and A/C use.
Please note that the condition of the chart is "Temp: 88 F -- About as hot as one can do without A/C & windows up for several hours".

We see approx 6% mpg down vs 10F lower temperature without A/C.
The A/C (heater in winter/cooler in summer) consumes certain amount of energy other than the driving energy, so there is a certain amount of mpg impact by the A/C usage.

I think 55 mpg at 60 mph in winter is not bad.
You will see 60 mpg at 60 mph rule in warm weather.

Ken@Japan

 

I try to use EV as much as possible and when available.
Am I doing something wrong?
On the highway I use the cruise whenever possible

 

You stated it very well, HMP.
vday, there are many threads here and at cleanmpg concerning this car. You should become adept at pulse & glide and the reasons it is so effective. It basically puts the excess energy of the ICE into kinetic energy instead of electricity, avoiding the conversion to and from electricity.