Hybrid Car – More Fun with Less Gas

Prius driving tips for a new user? - Page 2

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Posted by bwilson4web on August 10, 2011, 11:57 am
 

http://www.priuschat.com/
http://www.cleanmpg.com/

Note: I have no association with either web site as I've taken a
different approach.


This is a good start but you'll learn a lot more if you can get a
ScanGauge II to instrument the car. Be sure and get the one that is
XGAUGE programmable since these can also provide diagnostic codes. But
three built-in gauges will give three pieces of information needed to
drive efficiently:

 engine coolant - the Prius is very engine temperature dependent and
the simple rule is below 70C, it is an ordinary car and above 70C it
become very efficient. So try to minimize higher power demands until
the coolant reaches 70C.

 engine rpm - the engine efficiency of your model NHW20 is somewhat
sensitive to rpm with anything under 2,200-2,600 being very efficient
and above that less so. Under higher power settins, 3,200 rpm and
above, the car is less efficient.

 gallons per hour - unlike any other gauge, this gives a direct
readout of the rate of fuel consumption. Acceleration can still be
good with fuel consumption rates under two gallons per hour. But the
car really shines when fuel consumption is in the 0.60-0.70 range or
lower.


When the engine is warming up to 70C, I maximize used of "N" so the
engine will turn over at the minimum fuel consumption rate. But once
it reaches 70C, I only use "N" if I need to coast a longer distance.
Otherwise, I just used cruise control and pay attention to traffic.


My web page shows my approach to the problem:
http://hiwaay.net/~bzwilson/prius/

GOOD LUCK!
Bob Wilson

Posted by Bruce Richmond on August 14, 2011, 5:04 pm
 

I don't know what rate you used to accelerate at but I can tell you
that you don't have to accelerate all that slow to get good mileage.
Accelerating slowly lowers the rate of output, but it must be
maintained for a longer time to get up to speed.  Slowing
gradually,coasting down, makes far more difference.  You don't want to
waste the kinetic energy by turning it to heat in the brakes.  And
while regenerative braking recovers some energy, it to wastes a fair
amount as heat.


Depends on you plan :)  In the "pulse and glide" technique you don't
want to charge the battery, idea being that you never get as much back
as you put in.  An alternate method I use is to let off the gas to
shut the engine down, then gently step on the pedal to maintain 35 mph
with the electric motor.  When the battery runs down the engine will
start and recharge it.  The idea here is that the engine uses gasoline
just to idle.  When running on electric alone you save not only the
gas that would be moving the car but the gas wasted idling as well.
When the engine starts you have to replace the energy that was used to
keep the car rolling, but not the energy that would have kept the
engine idling.  It ends up giving better mpg than puttering along with
the engine running all the time, but not quite as good as pulse and
glide.  On the plus side you maintain a near constant speed.



Posted by Leftie on August 15, 2011, 12:21 am
 Bruce Richmond wrote:

     That's very true. I've been late for work a few times, and so was
pushing it hard, albeit in Eco mode so I had better throttle control. I
still averaged 49MPG, instead of the usual low to mid 50s. I've heard
that it will still get in the low forties running hard in Power mode.




     I also use the battery with the engine off, when I know that the
engine will have to run soon to climb a grade or accelerate faster. The
current average on the display, over several tanks of gas, is 55MPG.





Posted by Bruce Richmond on August 15, 2011, 11:04 am
 
I was speaking of the getting up to speed part only.  Keep the
eventual speed the same with the gentle planned slowing and the
acceleration will have almost no effect on you mpg.  The shorter time
spent accelerating makes up for the higher rate of fuel use while
accelerating.



Posted by Neo on August 23, 2011, 12:03 pm
 
1. The most important aspect of high fuel efficiency driving is to
     give yourself enough time to drive  to where you are going.

2. Hybrid usually donot achieve their rated EPA fuel efficiencies
    until after they are driven over 15 minutes at summertime
temperatures
    or over 30 minutes in the wintertime temperatures - this is
because
    there is a warmup penality to start up the engine and warm up
    the exhaust emisssions system. Whenever possible combine
    your driving trips so  that that most of your trips are longer
    than 30 minutes or 7 miles - this will automatically increase your
fuel efficiency.
    During the winter time, you can shorten this warmup penality
    for nonhighway/urban/suburban stop-n-go driving trips if the
    Prius intake grills are blocked and/or if you install a engine
    blockheater. During the winter, if the coolant temperature drops
    too low because the gasoline engine was automatically turned
    off ( because the Prius is at a stop light or because you
    are gliding for a long time) the Prius engine will go on
    automatically to warmup the coolant (which keeps the
    exhaust emission system at the proper operational temperatures).
    You want to avoid having the Prius engine automatically
    cycling on to warm up the coolant because it will cause
    your MPGs to drop like a rock. So you need to watch the
    temperature of the coolant when doing stop and go
    driving in colder temperatures - unfortunately the Prius
    doesnot have a temperature gauge so you need a ScangaugeII
    or something like it to check if the coolant is getting cold.
    Before the coolant gets too cold, I will pulse/run the gasoline
    engine more frequently just to to keep the coolant   from
    getting too cold in the winter time.

3. Daniel who wants to know is right to focus on the tire pressure
   -  the Prius fuel efficiency very sensitive to tire pressure. This
is
   because the tire's rolling resistance decreases with higher
pressure.
   The Prius will coast/glide longer on momentum without additional
   energy if it has a lower rolling resistance. Lower rolling
resistant
   depends on how smooth the road is and the tire rolling resistance.
   You can buy Low Rolling Resistant (LRR) Tires or you can
   overinflate a  tire near its maximum sidewall pressure setting
   to lower its rolling resistance. In addition, as the tread of a
tire
   wears off its rolling resistance decreases (but its stopping power
   decreases as well).  Overinflating the tires decreases the rolling
   resistance by making the tire more ridge - which can make for
   a harsher ride and a tire pressures over the maximum sidewall
   pressure can reduce the traction/gripping power of the tire. When
   the road surface is rough - an overinflated tire will not absorb
the
   irregularities but  *bounce* and rolling resistance maybe worst
   than if the tire was as a lesser pressure which would absorb
   road surface irregularities and not *bounce.*  If the road surface
   is rough or grooved due to construction then you'll  be better
   off with the tire pressure setting listed on the inside
   of the driver's door panel (manufacturer's suggested tire psi
setting).
   The advantage of the LRR is that they should do well regardless
   of the road surface condition at their recommended tire pressure
   setting.  Driving on a smooth well kept road helps fuel efficiency.

4. Avoid using more than 1/2  the high voltage(HV) battery power .
   When the HV voltage battery is nearly depleted the Prius gasoline
   engine will automatically go on to recharge the HV battery to push
   the power level back up to a safe level -- this in turn will push
the MPG
   down because that's the least fuel efficient way to charge the
   Prius HV battery.  Essentially this drives back to what
   Daniel who wants to know asserted - don't depend on the electric
   motors to drive the Prius to increase the MPGs - instead focus
   on efficiently using the vehicle's kinetic energy-momentum.
  when there are no arrows on the Energy Monitor Display - then no
   gas or electricity is being expended and the Prius is moving
   on its own momentum ( any object in motion will stay in that
   particular motion  unless acted by another force).

5. The Prius gets the best fuel efficiency if its running between
25mph
    to 35 mph nonstop for over 60 minutes - however this is not
practical
    in the real world most of the time.  When on the superhighway if
you
    keep your speed between 50 mph to 60 mph - you'll normally see
    much better   MPG results than if your speed is beteen 60 mph
    to 70 mph.  If you are driving above 50mph keep the windows
    rolled up - use the AC or the heater if you have too.

6. Cleanmpg.com is for hypermiling
       its the best place to get detailed instructions on how to
hypermile
   Priuschat.com is for Prius devotees and those who want to pimp
their rides
   Youtube.com has some very good video on how to drive a Prius
efficiently

7. I've read it is possible to use Neutral in a glide to decrease
internal resistance
    and extend a glide phase-  its an advance P&G technique.  On
priuschat
    F8L was asking that very same thing  under "extreme hypermiling"
    the problem is not that your momentum/kinetic energy will
eventually
    go to zero but that it the road section ahead has a much higher
energy
    cost per mph than the current road section you are on.  Each road
section
    is like a store where you can buy mph for X amount of energy.
Some
    stores are overpriced and other stores are cheap. So the best
tactic is
    to "Buy low, sell high." Simply put - the most energy efficient
route is to
    create speed when the energy cost to create speed is low then
    loose speed when the energy cost to create speed is high.


HTH

Walter Lee
2010 Toyota Prius III, Blue Ribbon/Dark Grey, oem floormats
Yokohama Avid S22 (50/48 psi)
ScanguageII (AVG, MPG/FwT. SoC, GPH)
odeometer +14800 miles, +59mpg overall,  10% Ethanol blend 87 oct
gasoline

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