I thought I drove it right but it drives me crazy.

Discussion in 'Gen 3 Prius Fuel Economy' started by bloo2013, Sep 10, 2013.

  1. bloo2013

    bloo2013 New Member

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    I'm a new (<4 mos.) owner of a Prius III after lurking on this site for a year or so. Great car, great mileage...

    ...but not good enough. I've got a roundtrip commute that I do in Los Angeles every weekday with little to no driving on the weekends. I go 7.2 miles from West Hollywood to Brentwood at 54-56mpg. After an hour I have an additional 0.6 miles to drive which nets me 46-47mpg.

    In the evening the inclines are reversed so the 0.6 mile commute is usually 24-25 mpg. The 7.2 from Brentwood to West Hollywood is usually 75-80mpg.

    That darn .6 mile trip in the middle ruins my mpg. I come out with 54-55 total rather than the 60s like I would expect. If I add one more short trip in the middle of the day, I'm even lower. What gives?

    Is there any way to not have the ICE fire up a few seconds after EVERY engine start and suck the gas away? Does anyone have any advice on how to handle necessary short trips to maximize mpg? Anyone else out there driving on the hills of Sunset Blvd. and Wilshire Blvd. and doing well?
     
  2. Munpot42

    Munpot42 Senior Member

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    Why would you expect 60's, most of us who are not hypermilers get somewhere in the 40's, and the epa rating is 50mpg, I'd be delighted to get even that.
     
  3. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

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    As already mentioned, you are beating EPA. Why would you expect 60+ mpg? You can achieve it, but it is not easy.

    The Prius is not made to be the most fuel efficient car. It is made to have the lowest pollution. The side effect of this is great fuel economy once warmed up. But the Prius does its best to warm the engine up fast to minimize pollutants. It runs the engine hot and doesn't use it unless it has to until it reaches Stage 4. During this stage, mid 30's is common on flat ground. It only lasts 1-2 minutes on normal days. Can last double that on cold days. A distance of 0.6miles will never get to S4 in moving traffic starting from cold. It is just not meant to do that.

    The only way to prevent the engine warmup is to drive in EV mode. Your Prius is not a plugin, so that will further hurt your tank average fuel economy. If you had a PiP, or even a PiP conversion, then that is the perfect time for EV only. In your case, you are doing quite well for including such a short trip. That's walking distance, so improve your FE and just walk.

    I live on a mountain so I climb a few thousand vertical feet every day. I get single digit MPGs on some of the climb. Tank averages are still mid 50's. The car is magic.
     
  4. SageBrush

    SageBrush Senior Member

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    bloo2013,

    55 average mpg for your commute sounds quite respectable. I doubt I could do much if any better, and I have been squeezing miles out of our Prii for close to a decade. Don't let the 0.6 mile jaunt annoy you too much: a lot of the energy is being saved in the battery for your later use. To prove the point, skip that trip for a few days.
     
  5. fuzzy1

    fuzzy1 Senior Member

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    Do traffic and slopes allow either of the 0.6 mile segments be done in EV mode? If so, it may allow you to skip engine warmup for one of those segments (not both), which should help round trip mpg. The evening segment would be limited to 9 mph to avoid ICE mode, but the morning one might have enough engine heat remaining to reach 25 mph.

    But getting 0.6 mile of EV will be a serious challenge without a PiP, and traffic or slopes could render it impossible. Even under ideal conditions, an OBDII engine monitor to watch temperatures might be essential.
     
  6. Agent J

    Agent J Hypoliterian

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    7.2 + miles one way is too short to net 60mpg. read up more on mild hypermiling techniques like ideal tire inflation, pulse and glide, traffic waves, local stop light sequence and fastest lane knowledge to get you conserving momentum which helps heaps on mpg! :)
     
  7. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Comments inserted.

    * * * original quote * * *
    I'm a new (<4 mos.) owner of a Prius III after lurking on this site for a year or so. Great car, great mileage...

    ...but not good enough. I've got a roundtrip commute that I do in Los Angeles every weekday with little to no driving on the weekends. I go 7.2 miles from West Hollywood to Brentwood at 54-56mpg. After an hour I have an additional 0.6 miles to drive which nets me 46-47mpg.

    In the evening the inclines are reversed so the 0.6 mile commute is usually 24-25 mpg. The 7.2 from Brentwood to West Hollywood is usually 75-80mpg.

    That darn .6 mile trip in the middle ruins my mpg. I come out with 54-55 total rather than the 60s like I would expect. If I add one more short trip in the middle of the day, I'm even lower. What gives?

    When the engine first runs, the car has to get the catalytic converter and oxygen sensors, O1 and O2, to operating temperature. During this 45-50 second interval, the engine runs in "closed loop" mode with a stored 'fuel trim' table. This is a rich, inefficient burn, so it is important to minimize engine load during this time. So you have a couple of options:
    1. Leave the car in "P" and wait until the engine shuts down by itself, usually about a minute. Use this time to lower the windows (let the hot air out); seat belts, and; adjust radio/iPod/iPhone and entertainment. Keep the A/C off for now. Once the engine shuts down, press the EV button and keeping your speed at or under 9 mph, creep out of the parking place and to the road you'll be taking. It is a good time to enable A/C if needed and raise windows. Then drive normally to your next destination but try to take slower routes and less aggressive accelerations in the first 1.5-2 miles as the engine coolant reaches 65C or higher.
    2. There is about a 5-10 second window when "READY" comes on to hit the "EV" button. If the car can go EV, finish getting ready and then creep at 9 mph or less to the road. Again, no A/C but windows down to let the hot air out. When you see a break in the traffic, pull out and accelerate using modest power (aka., lower half of power display bar) to speed and then shift into "N" at every opportunity to 'coast' with traffic. Shift to "D" as needed but back to "N" for the first 1.5-2.0 miles. The car will maximize use of the traction battery within limits (aka., the lower half of the power bar) and shifting into "N" will offload the engine . . . like it was parked. The fuel burn will be minimal while you proceed to your next destination. Try to practice this advanced technique on low traffic days until it become 'less strange.'



    Is there any way to not have the ICE fire up a few seconds after EVERY engine start and suck the gas away?

    There is no known way to 'cheat' the oxygen sensor and catalytic converter warm-up that works. The engine fuel trim (aka., rich or lean) is driven by these sensors and the engine coolant temperature.

    Does anyone have any advice on how to handle necessary short trips to maximize mpg?

    Asked and answered.

    Anyone else out there driving on the hills of Sunset Blvd. and Wilshire Blvd. and doing well?

    Hills offer an unusual advantage but it works best if you are driving on cruise control, all the time. The advantage of cruise control is it takes away the 'fretting' of a manually controlled accelerator. The cruise control uses a computer driven, Proportional-Integral-Derivative (PID) program to keep the speed within +/- 1 MPG of the set speed. Humans, sad to say, are less effective and often have excursions leading to excessive, micro-bursts. So step one is the learn how to drive on cruise control all the time. If this is foreign, practice until it become comfortable.

    Now if you on cruise control, switch the display to "Energy Flow" and keep a weather eye out on downgrades. If you see energy flow from the wheel-to-traction-battery, shift into "N". Monitor your speed and use "D" or "B" as needed to keep a smooth flow with traffic or whatever the posted speed limit is (or your tolerance.) Once the speed begins to fall off, shift into "D" and hit "resume" on the cruise control. What this does is let your "potential energy" provide motive power down the grade with the engine running at idle or below 42 mph, OFF. If kept in "D", the potential energy is converted into traction battery power, not a bad thing, but not as efficient as letting the car just coast down the grade.
    * * * end original quote * * *

    Here are more technical details.

    Bob Wilson
     
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  8. Pando

    Pando New Member

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    I disagree somewhat with above. Whether to use cruise control or not on hilly terrain - it depends on the size of the hill, the grade, and the traffic you're driving in. Cruise control keeps a constant speed. It also has the tendency to rev the engine excessively on steep upclimb just to maintain that speed, burning a lot of fuel, even though a human could see the crest and slow down, allowing the car to use its momentum to make it over the crest and then downhill. Cruise control can't do that, unless your car uses digital elevation data to plan the route and most efficient speed (which it does not, yet).

    Then again, by slowing down uphill you'd drive the people nuts behind you. Unless you're completely alone on the road, or trying to beat a world record (in which case you should have an escort with blinking lights), please drive responsibly and go with traffic instead of trying to milk every ounce of gas out of your Prius. Time is money too.
     
  9. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Actually I 'pat down' to take the load off the engine and 'pat up' as needed to meet traffic needs. Each UP or DOWN operation of the stalk adds or takes away 1 mph on a flat surface or can moderate the engine load if you have instrumentation.

    I always recommend following the slowest local traffic up the hill . . . semi-trailer trucks are great and often have a hill-climb lane. I just use them as my 'pacing vehicle' and cruise control to adjust to local traffic conditions.

    Learning how to drive on cruise control is different than using the accelerator. But practice makes driving a whole lot easier.

    Bob Wilson
     
  10. Aerolite

    Aerolite Junior Member

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    Did a quick drive and recorded the results, this was an absolute hyper mile trek 74.5 MPG:

    [​IMG]

    Nearly any Prius owner can get that kind of MPG but breaking past the 50 MPG hurdle requires focus and technique.

    That drive was done 60/40 (highway/city)... with windows up, no AC, gentle acceleration, pulse and glide, and cruise control set to 50 MPH.

    With the way I regularly drive I get a around an average of 65 MPG (+\- 2mpg).
     
  11. Former Member 68813

    Former Member 68813 Senior Member

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    24 MPH average 60/40 hwy/city?

    I would hate to drive behind you.
    I drive 100% city/suburbs and get better average speed!
     
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  12. Aerolite

    Aerolite Junior Member

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    I don't doubt it ;)

    Southern Califnora, believe it or not, isn't the optimal place for high MPG... lots of hills.

    I usually don't drive like I had above, just to prove that the OP's Prius is not "broke". High MPG is a pure function of driver skill multiples by surrounding environment. Like I said, my normal commute net's 65 MPG (70 % hw/ 30% city).

    What figures are you pulling?
     
  13. Agent J

    Agent J Hypoliterian

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    24mph @ 65 mpg is really good! the hwy/city ratio is really not looking at the whole picture. maybe the hwy part is usually slow moving and the city part worse.

    I drive 20 miles each way and only get 19.88 mph avg at best with about 10/90 ratio. However, I'm no slow-poke as I still get ahead of most of the cars on the road. It's just the volume of cars on my commute plus it's also hilly.
     
  14. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Or just drive efficiently on cruise control at a selected speed AFTER warm-up:
    [​IMG]
    Warm-up takes about 2-3 miles, about 5 minutes, and runs about 30 MPG. Continue driving on cruise control at the selected speed, say 90 [email protected] mph for 55 minutes and the MPG will approximate:
    • Warm-up, 5 min ~= 5*30 = 150 MPG min
    • Cruise control @30 mph, 55 min ~= 55*90 = 4950 MPG min
    • MPG over 5+55 min ~= (150 + 4950) / (5 + 55) = 85 MPG
    • Distance ~= 30 miles for 5+55 minutes, one hour
    Using cruise control, it is pretty easy to achieve any desired MPG after warm-up.

    In my case, a 10 mile work commute, ~20 minutes, I'm paying a significant warm-up penalty. So I'm seeing ~52 MPG year after year. In the winter, lower than 52 MPG, and in the summer, higher than 52 MPG. Fall and spring run about 52 MPG.

    Bob Wilson
     
  15. fuzzy1

    fuzzy1 Senior Member

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    Do you have to stop for many traffic lights on your city / suburb routes? Are any of them three minute lights? Do any of them have enough congestion that you must wait multiple cycles per intersection?

    Some of us occasionally must deal with more stop time than go time, seriously dragging down the average speed. Unlike a typical bicycle computer, the Prius includes all that stationary waiting time in its average speed computation.
     
  16. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Efficient driving using cruise control with at least two, cold-soak, warm-up cycles:
    [​IMG]
    I couldn't remember the exact MPG but thought it was in the mid-70s.

    Bob Wilson

    ps. I usually take a nap after supper and wake up a little after midnight. As I've gotten older, I don't think I'm sleeping as much as before. Regardless, my wife's two little dogs are also up and I have to 'run their springs down' by taking them work and letting them run around the empty parking lot. When we get back home, they go right to sleep! I'll also go into the office and check what crisis d'jour is brewing and if I don't fix it then, work the problem during the business hours.
     
  17. Michael King

    Michael King Member

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    Bob. Goto Bed. Taking a photo at 3:42am to prove a point gives me a headache (or is it a yawn).

    Anyways, to corroborate Bob's Chart.
    I drive 80 miles each way to work, on the highway, with the cruise control mostly set at 65mph. (Sometimes faster if I'm very late, and slower if I'm stuck in traffic (not usually))

    Here's my Fuelly Graph for the last 9 months. I almost always see my average when I shut the car off being 55MPG for my commute trip. (BTW, I don't know if that graph is going to post, I'm trying to link it from my google plus page)
    [​IMG]
     
  18. Joeteck

    Joeteck Junior Member

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    I'm a new 2013 Prius III w/solor roof 9-13-13.jpg owner too. About three 3 weeks old. Bought it the end of August. I just drove about 35 miles using cruise control. I achieved 63.3 MPG @ 60MPH. My cruise was set, and it did a great job. I'm very impressed so far.

    I see no reason to buy any other car but the Prius. Why would you? Makes to sense to me... If you are looking at a car for $30K, then the Prius would be the only car for you...
     
  19. Aerolite

    Aerolite Junior Member

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    100% agreed

    Haha, I got my '10 Prius 4 w/solar roof in early August. I used to get a 65.5 avg. MPG it took careful maneuvering and CC set to 55 MPH on freeway.

    Now that I mixed up my habits (have needed to speed up certain trips) my average dropped to 59.5 MPG over the past 450 miles.

    Mind you I have Michelins Energy Saver so the diff. in output is a direct relationship w/ my foot.
     
  20. Joeteck

    Joeteck Junior Member

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    People may think the Solar roof is a waste of money, but I need my moon roof, the Solar roof was a bonus and because I have it, my car is cooler than cars without the solar roof which ventilates the car's interior air with what is outside the car.. I never get into a hot car. Plus we have the ability to start the A/C from our remote for 3 minutes; it runs on the HV battery. So clever!
     
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