Need an "ECO Cruise Control" Setting

Discussion in 'Gen 4 Prius Fuel Economy' started by Valiant V, May 8, 2021.

  1. Valiant V

    Valiant V Member

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    I don't know if this is a "Feature Request" or just a bit of a rant.

    It's always bothered me that cruise controls - which had (at least at one time) been promoted as "gas saving" since they'd keep you at a constant (kinda) speed instead of the wasteful accelerate/decelerate/accelerate unsteady foot many drivers use. Bun in every cruise control I've used, you get to a hill and the pedal goes to the metal and I've even had cars downshift and scream to keep the speed setting. I would generally kick off the cruise and apply the accelerator a little more judiciously.

    I'm really impressed by the "Dynamic Radar Cruise Control" - definitely the most sophisticated cruise control I've ever used. Normal cruise controls will happily drive you into the rear end of a slower car ahead of you. This one won't.

    That said, how much more difficult would it be to have a mode that "drove" more like a economy-conscious driver. Indeed, a cruise control that follows the very suggestions that a Toyota "Hybrid Driving Tips" video recommends: when driving up a hill, allow a reduction in speed rather than stepping on the accelerator to maintain a constant speed.

    Sure - some might say there are safety concerns - like the guy behind you NOT slowing down and rear ending you. Yeah, that's possible - if we are counting on our car to do all of the driving (and thinking) for us. That would certainly be no more unsafe than me slowing from 70 to 65, 63, or even 60 while not using cruise control while ascending a hill. After all, I'm probably gonna "coast" up to 72, 73, or 75 heading down the other side.

    Anyway, with a car with as many computers and tech in it - I'm surprised that a cruise control that accelerates more *gently* isn't part of the programming. If you didn't want that behaviour - you could always turn it off - like you can the DRCC.
     
  2. The Professor

    The Professor Senior Member

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    You can toggle how heavy-footed the DRC is by changing Driving Modes between Eco, Normal, and Power. That being said, even in Eco it'll still take the accelerator into the red when going uphill if it's necessary to maintain speed.

    I'm not sure if you can actually do what you want here though. I'm gonna have to think about this a bit more, but in the Hybrid Synergy Drive, you're not directly controlling the revs / "gear ratio", or speed with the accelerator, you're controlling how much power is being dumped into the wheels. Like I said, I'll have to think about this some more, but I have a feeling that on a given gradient, there will be a given spot on the accelerator gauge that allows the car to maintain its current speed. Anything less and it'll continue to slow down to nothing, anything more and it'll continue to accelerate. Now I know there's more to it than that (air friction, etc), but broadly speaking, I suspect what you're wishing for can't happen, because the computers are already simply trying to maintain the set speed. If it could drop into the "Eco" accelerator range for that gradient the car would slow way down or stop.

    Again... would have to test it on a hill to be sure, but I have a feeling that's the case. My main experience here is the hill up to my house. It's a constant gradient for about half a mile and it's a 30MPH limit. I know that I need about 75% on the Eco section of the accelerator gauge to maintain 30MPH up that hill. I know if I'm a even a tiny bit higher it continues to speed up until I notice (let's say 40), and if I'm a tiny bit lower I've had it drop all the way to 15MPH before. Never gone lower but I could try.
     
  3. davecook89t

    davecook89t Senior Member

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    I certainly agree that it would be nice if a car's cruise control could be programmed to reflect a driver's preference in maintaining speed vs. saving fuel, but I suspect creating an algorithm for that might be almost as complex as creating one to fully enable self-driving, and I would prefer that manufacturers focus on that first. Maybe an intermediate step would be to allow drivers to select a driving mode along a continuum, rather than being forced to choose between Eco, Normal and Power mode. If that could be integrated with the cruise control function that might be closer to what you would like, but to ask the car to decide how much power to supply to the wheels on a particular slope would be asking it to read your mind, a task even more difficult than deciding whether to slow down, change lanes or stop if the car's camera sees a particular road or traffic condition.
     
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  4. jerrymildred

    jerrymildred Senior Member

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    I don't think it would be any harder than the nice feature on my new programmable thermostat for my house. It has nine settings that let the temperature swing by anywhere from 0.25ºF up to 2.25ºF. Setting #1 (the default) keeps the temperature in a narrow band starting & stopping the AC frequently. Setting a wider band lets the temperature fluctuate more while reducing wear on the motors from frequent starts. Something similar could be done with a cruise control while also altering the speed of the throttle response.
     
  5. Prodigyplace

    Prodigyplace Senior Member

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    The Gen 4 DRCC is already too sluggish in Eco mode even here in the rural South. Imagine the cussing in the North from those following a Prius.
     
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  6. Aaron Vitolins

    Aaron Vitolins Senior Member

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    I always felt this way too, for such an eco car the cruise control is pretty aggressive holding the set speed.

    My Ford hybrid does have Eco-cruise control: you can turn it off or on. It doesn’t make a huge difference but it’s noticeable. It will let it drop a mph or 2 on hills. So it can be done! Come on Toyota :)
     
  7. alanclarkeau

    alanclarkeau Senior Member

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    Sounds like you want a DRCC which will "HYPERMILE".

    It isn't going to happen. Hypermiling is something I sometimes engage in - if I haven't got traffic behind me, if I know the terrain and whether there is another hill over the crest, or a big decline to recharge the battery.

    For your DRCC to do that, it would have to be GPS linked, with all-round cameras ... and a conscience.
     
  8. sam spade 2

    sam spade 2 Senior Member

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    You have an ECO cruise control.
    It is the accelerator pedal.
    :)
     
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  9. Valiant V

    Valiant V Member

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    ...which is what I fallback to.

    On a 400-mile trip that I just took the Prius on for the first time, I used the DRCC on the relatively flat sections of road, and kicked it off for hilly areas.
     
  10. Valiant V

    Valiant V Member

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    I don't think I'm asking for a CC with a "Hypermile" feature - just one that doesn't floor the accelerator when you hit a hill. A little moderation is all I'm asking for. I mean, If you can program how fast the Heat/AC fan speeds up - then why not the CC?

    BTW - this has been a pet peeve of mine with cruise controls long before I bought the Prius. No way a cruise control should put the pedal to the metal and cause a downshift (in vehicles other than a Prius or CVT of course). It's terrible for mileage, puts extra wear and tear on the drivetrain - and - it wakes me up when I'm snoozing. Who needs that!? :p
     
  11. alanclarkeau

    alanclarkeau Senior Member

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    I know what you're saying - but DRCC's role is to maintain the speed.

    For it to know how much you - or I - or John - or Mary - want it to allow it to slow down, would need a brain implant. It does what's on the bottle's instructions.

    ECO Mode it doesn't hold the speed always though, not like PWR.
     
  12. Valiant V

    Valiant V Member

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    Sure, I get it.

    But one has to admit - that the "bottle's instructions" on a Prius are pretty intricate in the case of the rest of the car's systems - so I don't think we're talking leaps of technological advancement to do what I'm suggesting.

    Just look at the "ECO Accelerator Guide" - it never pushes into the "PWR" range - yet the manual says we should stay within that arc for best economy. So the data and guidance already exist: Just have a mode where the Cruise Control stays withing the ECO accelerator Guide. Sure, maybe nobody will use it once they've tried it once - but at least it would be there for folks like me. Hell, I've never even considered using the "Normal" or Power" modes yet - IMHO those are kinda out of place in a Prius.

    I promise not to beat this dead horse any longer - but I think if the engineers who conceived and designed the whole Prius family of vehicles had yielded to the "It's too difficult, there's no way of doing that" mentality - we'd all be on Ford F150 chat.
     
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  13. alanclarkeau

    alanclarkeau Senior Member

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    Give em a go - "Normal" or Power" are useful at times. I find with DRCC in heavy traffic, PWR is much better as traffic behind don't get upset, and it keeps in better range with the car in front. To be honest, I've not noticed much difference in litres/100km between either setting.
     
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  14. Valiant V

    Valiant V Member

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    You can tell that folks around where I live are rabid NASCAR fans from the way they'll "draft" (tailgate) you a car-length away or less at 65-70mph (even then the posted speed limit is 60). Frankly, I've long since stopped caring if they "get upset" or not as it's about impossible to get these guys to follow at a safe distance unless you're willing to do 85+ in a 60mph zone. (IOW - you shake them off.)

    I live in a rural area with hills, winding roads, blind driveways, and frequent road incursions by coyotes, turkey vultures, feral hogs, and even stray cattle on the road. Since a feral hog can total a full-sized truck, and even a turkey vulture can take out a headlight, grille, or radiator/AC condenser - I'm not gonna plow into any of them at cruise speed. If I hit the brakes to avoid any of the aforementioned roar hazards - the clown following 9 feet behind me IS going to rear-end me. So how fast I speed up after I slow for another vehicle or whether I maintain the posted limit (plus 10) up a hill is pretty much an academic concern.

    Being an older, wiser driver - I've given up on "brake-checking" the tailgating knuckleheads - but I certainly don't give a second though to how they "feel" about me going "too slow".
     
    #14 Valiant V, May 15, 2021
    Last edited: May 15, 2021
  15. MIkeDr

    MIkeDr Member

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    in my limited experience driving the Prius on road trips, I’ve noticed that there appears to be a perception that people think you’ll be driving slow because you’re in a Prius. Even though I’ve set the cruise for 85.

    but otherwise I feel the same as you. After living in Arizona where many people carry guns in their cars, and hearing stories about people shooting speed enforcement cameras, I’ve learned to just to let things slide.
     
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  16. Valiant V

    Valiant V Member

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    The only thing "slow" about my driving is I generally don't floor it to get up to the speed limit (or above) in 3 seconds or less. That was true even when I was driving my old 2000 Ford Ranger with 344,000 miles on it. I'm not gonna beat on my cold engine just so the guy behind me doesn't have to worry about other vehicles on the road.

    I live on a hilly, winding, narrow country road and happen to have what I would call a "blind driveway". Even if I look both ways twice and assure that no one is in sight, by the time I hit the center line making my left turn onto the road from my driveway - someone is on my tail. Sorry bud, you're GONNA have to take your foot off the gas and deal with having to share the road with others.

    The road I live on is officially designated a "Farm to Market" road - so their purpose is to enable farmers and ranchers to bring their stuff to town. It's very common for feed trucks, cattle trailers, combines, and tractors and hay rakes to pull onto the road - and go 7 miles an hour for a mile or six. So having to deal with my not flogging my engine should be the least of their worries.
     
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