FuelEconomy.gov official ratings posted - 58 City/53 Hwy Prius Eco - 54 City / 50 Hwy for Prius

Looks like our 2010 Prius will be upgraded to a 2016 Prius Eco model. Even though I am not crazy about its looks its like my
Mom told me that beauty is only skin deep. When I bought my first new car in 1977, a 1977 two door base model VW Rabbit
Diesel 4 speed manual, no ac,no power steering, manual roll down windows etc. It was not the looks that caught my attention it was the 50 mpg with, at the time; cheap #2 diesel. It was a great run with well over 200,000 miles before I gave it to my dad who sold it to a helicopter pilot probably for the use of jet fuel with a little oil thrown in for fuel lubricant.

 

Miles on the 2010?

Ours is just under 70,000 miles but then I use our 2003 for commuting.

Bob Wilson

 

wait, wait wait, how is pip cheating, if you don't plug in?

can you elaborate on the change in cvt operation? sounds interesting!

 

Difference between city and highway fuel economy:
Gen 3: 3 mpg
4 standard: 4 mpg
4 Eco: 5 mpg
And this despite of the small improvement in aerodynamic !

I assume most of the increased difference is due (or thanks) to the increased regen power capability which is more of a factor in city drive.
Active shutters may also contribute (cold start in city cycle).
I wonder how exactly these shutters work? is it only on/off operation? or proportional to engine temp? will they partially close at highway speeds flat road when engine temp may drop below optimum?

 

it may just be the test according to some reviewers, much easier to do better in practice than the gen3.

 

Without metrics, the weighting is only my estimate of importance:

1. Improved warm-up - shutters
2. Improved control laws - the engine can turn stop turning at higher speeds than today(*)
   
3. Improved aerodynamics - shutters help here too along with body changes
4. Improved rolling drag - independent rear suspension makes rear toe and camber much easier to fix
5. Improved thermodynamics (*)

IMHO, the 2016 is like a sailplane compared to efficient, general aviation aircraft, like a Mooney.

Bob Wilson

* - Using MiniVCI/Techstream, I was able to measure 2010 efficiency at 37.8% in some modes. My Christmas present,
OBD Mini Logger™ | HEM Data, is giving similar numbers with more details and insights about the operating modes. Sampling interval with MiniVCI is ~900 ms versus less than 100 ms with my new tool and it claims it can go down to 20 ms. It is the difference between a Cracker Jack, plastic lens and a high school microscope. To go finer, would be fun but takes too long to analyze.

 

Hi Bob,

You probably do mostly long stretches of rural driving, with medium operating speeds (40 - 55 MPH), where MPG is the highest. This falls into neither city nor highway driving. You are probably a big-time hypermiler, too, driving as if the gas pedal is made of an egg shell.

 

Uh no on hypermiling. I drive:

• Light load during warm-up
  
• Cruise control everywhere
• Keep rpm under 2700
• Avoid over 3900 rpm
• Shift to N when traffic permits and engine off
• Shortest, Prius friendly route

Bob Wilson

 

Which are all techniques that fall under the general practice of basic hypermiling. Except for the cruise control use; on some cars, it will rev too high to regain lost speed due to inclines.

 

funny how skeptics find 52 mpg 'amazing'. smoke and mirrors.

 

Interesting that you get the same MPG either with Gen 1 or Gen 3. Gen 1 must be very fuel-efficient for your particular operating conditions.

 

The Gen 3 gets 52 MPG at +5 mph. So on trips to Nashville, the 03 runs at 65 mph and the 10 runs at 70 mph. Since there are hills, I use semitrailers as my pacing vehicle when ascending hills. Their power-to-weight ratio is perfect to keep the climb in engine-powered mode and avoid dipping into the traction battery.

What I don't do (and strongly disagree with!)

• pulse-and-glide - the maximum savings is not proportional compared to attention to basics
• 'feathering' accelerator - nonsense that is impossible to quantify

Efficient driving is simple:

• No pulse-and-glide
• No feathered accelerator
• No turning off car while in motion
• No jumping out and pushing a car
• No advocating style over engineering (aka., Top Gear)
  
• No personality over metrics

Efficient driving is:

• Cruise control speed management
• Measuring car metrics to identify 'knees in the curve'
• Engineering metrics to identify efficiency points

Bob Wilson

 

driving the speed limit saves.

 

For Bob Wilson. Our 2010 Prius III was purchased in May 2009, odometer is reading a little over 135,000 miles. Still going strong with no
battery degradation that I can detect. MPG calculated is 45-47 winter / 53-58 mpg summer. 10% ethanol reg. gas...

My wife vehicle is a 2014 volt and we have a 240 Volt charger, probably the best of both worlds for us..

 

Feathering the accelerator will give the same benefit of shifting to neutral when not driving at highway speeds. They both put the system into a mode where regen isn't happening; a glide.

My experience with cruise control is that its success for efficient driving is terrain dependent. On level pavement, it is as effective as driving with load, but easier. On hills, it comes down to how steep they are. Because cruise control is reactive, it can lose 2 to 5 mph before taking action to maintain speed, and when it does, it floors the accelerator for the entire climb.

 

I'm not sure why you shift to to N while driving.

Firstly because the benefit is not clear to me with a Prius.

Secondly because I understand that there are some safety concerns (not sure if they apply in a Prius)

Thirdly because my understanding is that coasting in neutral is illegal in some jurisdictions including Alabama Section 32-5A-57 - Coasting prohibited. :: 2013 Code of Alabama :: US Codes and Statutes :: US Law :: Justia

 

If there were a clutch, I would use it instead. I shift into "N" because that eliminates the synthetic drag, which remains high on my list of improvements needed in the Prius. FYI, I have contemplated an automatic "N", microcontroller.

As for the 'legal' issue, there are more interesting things for our cops to enforce: (1) speeding, (2) tail gating, (3) cell phone use, and (4) driving while impaired. Checking the shifter position is a little difficult unless they notice my MPG numbers:


Bob Wilson

 

Why would shifting to neutral increase the MPG? Entire output of the engine is being lost. I thought engines were designed to burn the least fuel if they were kept in D while going downhill. Also, you are increasing the emissions.

I think it's overdue for the government to mandate GPS recorders on all cars. They can check against the speed limits, driving habits, and things like coasting, etc. You would get automatic speeding tickets, coasting tickets, and so on. They could also tax based on the driving habits and mileage. It also has tremendous security benefits against anyone trying to commit a crime and using a vehicle to get away or get there while doing so.

 

How about using the in car microphone to check for accents and add a camera to determine skin tone. I feel the highways getting safer all the time.

 

There is nothing discriminatory about having a GPS recorder. Driving is a privilege, not a right. You are not entitled to break the speed limits and other laws and you can't claim discrimination for being cited for breaking the law. More enforcement on driving, such as with a GPS recorder, will make the world a better and safer place.