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Motor kicks in at low acceleration

Discussion in 'Gen 2 Prius Main Forum' started by GaryKaren, Jan 26, 2004.

  1. GaryKaren

    GaryKaren New Member

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    All the reading I have done leads me to believe that when accelerating very slowly, only the motor would be needed and used. This is not the case for my wife and me. No matter how gently we accelerate, the engine kicks in for power at perhaps 3 or 4 mph. Is this what others experience?

    We are at the end of our first tank of gas and so far (according to the computer) are getting about 38 mpg. Our expectations were certainly for better than this. Granted it has been very cold here in eastern PA since we took delivery and my wife's commute is pretty hilly, but we've been driving pretty gently and we get tons of re-generation. Our battery is almost always "full". Should we be concerned?
     
    #1 GaryKaren, Jan 26, 2004
  2. Wolfman

    Wolfman New Member

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    With the temperatures that you guys have been having in the Northeast, what you are experiencing is normal. Wait for warmer weather. Stealth mode will be much easier to get. I routinely drive stretches of various roads where I live, where I can keep the engine off. When we have cold snaps here (and we're heading into another one today), the engine does run more. Your fuel economy will go up as well. Another pointer will be when it finally does warm up in your neck of the woods, you will find that your calculated (if you are doing this) fuel economy will actually drop for a tank or two, as the fuel tank bladder increases in flexibility and capacity.
     
    #2 Wolfman, Jan 26, 2004
  3. cybele

    cybele New Member

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    Yes, it sounds perfectly normal. You're still in your break-in period and it is rather cold in PA.

    I'm only 1000 miles into my car and have already noticed that it's easier to find stealth at lower speeds. The important part, I've found, is that the car is is warmed up. As an example, I live at the top of a hill. So when I leave for work in the morning (today it was 45 degrees), even though I'm coasting down a rather steep grade and haven't hit the gas pedal for several blocks, the engine runs to warm the car up. But at least it's regenerating.

    Once the car is warmed up though, I'm finding it much easier to get stealth acceleration on flat or downhill stretches.

    I do find that my hilly neighborhood really lowers my mileage.

    My first tank was 40 MPG, the latest was 47 or so. (Granted, I'm in a warmer climate.)
     
    #3 cybele, Jan 26, 2004
  4. GaryKaren

    GaryKaren New Member

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    I appreciate the guidance. At the risk of embarrasing my technical self-esteem... bladder?! Are these normal for most cars these days?
     
    #4 GaryKaren, Jan 26, 2004
  5. Wolfman

    Wolfman New Member

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    No, fuel tank bladders are not typical installations. Toyota has elected to use these as part of their emissions equipment to minimize fuel vapors.
     
    #5 Wolfman, Jan 26, 2004
  6. efusco

    efusco Moderator Emeritus
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    1)No, most cars do not have a bladder inside the gas tank. This is something to help reduce evaporative emissions.

    2)As others have stated, you shouldn't worry about the difficulty staying in 'stealth' when starting from a stop. It becomes easier to do as the car breaks in, and with warmer weather. Last night, on my way home from work at 2:30am, the roads were empty. The temperture was about 23 degrees F and I'd been driving pretty slow anyway due to some dense fog and slick roads. I decided to see if I could take off in stealth just for the fun of it. I could....I managed to get about 100 yards and up to about 40mph before the ICE kicked in!

    Now, saying all that...it doesn't matter. There is really no advantage what so ever to taking off in stealth mode. In fact, it is probably LESS fuel efficient to do so due to the lower efficiency of converting energy to the battery then back to the motor. I think it's nice that one can break the static friction from being stopped with just the motor, but once that's done you're just as well off having the ICE kick in until up to speed. One of the problems is that the advertising and 'reviews' in various magazines tout the ability to take off in stealth as some kind of benefit--I thought it was too. But it really isn't. I think it's a benefit when I'm sitting in a long line and creeping forward a few feet at a time, but if you're stopped and have to accellerate up to 35mph+ you WANT the ICE to kick in ASAP.

    A great question. There's not a darn thing wrong with your car.
     
    #6 efusco, Jan 26, 2004
  7. behmon

    behmon New Member

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    I too live in SE Pennsylvania. How long is your typical drive? And, are you using the heater full-time? I find that once the Prius warms up (as well as the cabin) the heater blowers reduce and the car will run in stealth for a short distance after a stop. I believe the cold spell we are experiencing is the cause of the ICE running more than we expect. :wink:

    Ditto. My first tank also averaged in the upper 30s. However, since I surpassed the break in period I am seeing an improvement. My last tank averaged in the mid 40s and I expect this to improve with future tanks of fuel - even moreso as the weather warms. :D
     
    #7 behmon, Jan 26, 2004
  8. charlieh

    charlieh Junior Member

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    As an owner of an '03 for 17,500 miles and now an '04 for 2500 miles, I can agree with you on the ICE kicking in very easily compared to my '03. However, as has been pointed out, using the ICE is probably the best way to get to "cruising" speed in the city and then just keep gently backing off the accelerator until "stealth" is achieved (assuming you are on level or downhill terrain, of course). Hills will kill your mileage. Tire pressure makes a difference as well. I run my '03 at 42/40 and the '04 at 44/42. The ride is a bit stiffer, but it seems that stealth is more likely to happen and the mileage is certainly better. Short hops will ding mileage as well.

    On the basis of my experience in my '03, I really thought that my '04 would be doing closer to 62 around town. That, I am afraid, is NEVER going to happen. I can easily pull 52 mpg on my '03 around town (around 35 mph, mostly flat). You really have to drive for mileage (which if you live in LA like I do, the guy behind you will have a fit) when you can. Rush hour makes everyone crazy so the mpg drops as I try to keep from getting run over. Late at night I can get MUCH better mileage because I can drive for it without annoying everyone.

    Good luck! I hope you like your car as much as I do.
     
    #8 charlieh, Jan 29, 2004
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