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Discussion Starter #1
Hey all, I've tried googling around for the answer to this but haven't found anything. Does anyone know why the Accord doesn't brake to maintain speed when going down a hill with cruise control on? It seems strange, in my opinion, that the car obviously has the ability to electronically brake while using adaptive cruise and a car in front of you slows down. Yet, if I have my cruise set to 70 and there is no one in front of me and I go down a hill, the car speeds up indefinitely. Is there a setting I'm missing somewhere? It's strange to me that this isn't a default behavior when the car obviously has the capability to do so. Thanks!
 

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Cruise controls are generally set up to add power to get up to a speed and lower power to 'settle' on a speed with drag but don't throw the brakes into the equation.

ACC will first coast (let up on power) and then finally apply brakes to adjust in order to avoid getting too close to another car.

Having the capability to use brakes to convert free energy into waste heat doesn't strike me as a sound engineering decision. Leave it to the driver to be safe (and/or avoid tickets). I like the free energy a hill will give and generally won't brake unless safety demands it.

Further, I don't think you'd like the feeling of the brakes coming on and letting off repeatedly either, nor the excessive wear on them...
 

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Discussion Starter #3
It definitely is a feature in more luxury cars; I know BMWs do it automatically, even ones without adaptive cruise control. I see what you're saying about the free energy, I just wish I didn't have to cancel my cruise control to avoid going 85 down long steep hills.
 

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Page # 538 of your Owner's Manual


518465



Do not use ACC under the following conditions:
•On roads with heavy traffic or while driving in continuous stop and go traffic.
•On roads with sharp turns.
On roads with steep downhill sections, as the set vehicle speed can be exceeded by coasting. In such cases, ACC will not apply the brakes to maintain the set speed.
•On roads with toll collection facilities or other
objects between lanes of traffic, or in parking areas, or facilities with drive through access
 

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Discussion Starter #5
Ok, sure, I hate this type of reply tho because it's unnecessarily rude and I guess I'm also just trying to open a discussion around why they made this not possible when the car obviously has the capability to apply the brakes electronically?

It's the difference between "adaptive" and "dynamic" cruise control I guess. Adaptive can include dynamic (braking in all situations to maintain speed) but the two are not mutually exclusive I guess.
 

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Generally speaking, I haven't seen automatic transmission cars actively engine brake by downshifting. This is what you should do when you want to maintain speed going down a steep hill. You don't end up wasting brakes or worse, suffer brake fade if the stretch is long enough.

In the manual Accord I drive right now, I go up a hill going to work and down a hill going home. The slope is 7% and when I go down the hill, I would just downshift into 4th from 5th to maintain the speed under 110km/h or 70 mph.

If your Accord has a paddle shifter, you could downshift a few gears and see what happens. I am not sure how the CC works on cars with paddle shifters. Does it cancel when you paddle shift?

Sent from GM1917. Technology!
 

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Ok, sure, I hate this type of reply tho because it's unnecessarily rude and I guess I'm also just trying to open a discussion around why they made this not possible when the car obviously has the capability to apply the brakes electronically?
You are welcome. You asked: Is there a setting I'm missing somewhere? The owner's manual is available online, for free! You can download it to your smartphone or have an intern print out the whole thing.

As for "why this is not possible?", I too look forward to the discussion that may be updated from previous threads asking this. Page #538 of the owner's manual does not answer this.

The picture of Richard Kiel ("Jaws" in the James Bond movies) is from a famous Twilight Zone episode called "To Serve Man". In that episode, humans who did not read the book titled "To Serve Man" that the alien presented to them (other than the title, they did not have it translated yet) willingly got on a flying saucer thinking that they were going on vacation to another planet. Only at the end did a scientist scream out "To Serve Man- it's a cook book!"

Ironic, isn't it? If those humans read the book, they would not have gone on that flying saucer to become food for these aliens.
 
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It definitely is a feature in more luxury cars; I know BMWs do it automatically, even ones without adaptive cruise control. I see what you're saying about the free energy, I just wish I didn't have to cancel my cruise control to avoid going 85 down long steep hills.
Well I guess you need to buy a BMW to have what you desire.

You could downshift as UJX suggests too.
 

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Or, you could buy an F-150. Mine downshifts to control speed with Cruise Control set in downhill runs. It's helpful when towing.

I don't see the speedup in downhill driving particularly objectionable in my car. If I want to control it, I just pull the "minus" paddle to apply regenerative braking, but this DOES cancel ACC.

- Jack
 
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IDK about indefinitely, maybe up to 85 or 90, but not indefinitely. I should add that I drive a 6 speed, so my top gear ratio is not the same as the CVT or 10 speed automatic, so maybe my engine is braking for me at those speeds. You could always pay a senior citizen to drive in front of you at the speed limit, then you'll have adaptive cruise AND it'll obey traffic laws.
 

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I'm trying to recall what our Accord Hybrid does on a steeper downhill, with cruise control on. Since mild slowing of the Hybrid is accomplished by regenerative braking, not actual use of the brake pads, it would make more sense (from an energy-conserving viewpoint) to apply some regenerative braking to maintain the cruise control speed. But I can't recall if this happens automatically, or not.

In any case, the paddle shifters on the Hybrids can be tapped to have varying levels of regenerative braking during "coasting". So if the speed starts to climb on long downhills, you tap the paddle shifter to get more regenerative braking (with the feel being somewhat akin to downshifting)...
 

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I'm trying to recall what our Accord Hybrid does on a steeper downhill, with cruise control on.
For most Hybrid posters, yes. Maybe something to do with Eco mode?
 

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My Hybrid applies NO regn braking on it's own to maintain speed going downhill, with ACC engaged. But, if I overtake a slower car ahead, it slows nicely to follow.

- Jack
 

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I have to admit I was not present in the meeting where Engineering Director and Sr. Mechanical Design Engineer discussed this and came to the agreement to not to have this feature, but if I had to make a guess, it would be: "Because transmission's job is to manage the relationship between torque demand and engine rpm, while brake pads' job is to manage vehicle speed by converting excess kinetic energy into heat".

For those who ain't got time to read: "Brake pad cheap. Transmission no cheap."
 

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I have to disagree with some folks here. I previously had a 2014 Mazda 6 and believe it or not, it had the feature of a steady adaptive cruise control which was really convenient for me, and it used to brake to maintain the speed, and it wasn't a beemer :)
 

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It could be a safety (read: liability) issue, also. Just like it is not recommended to use CC on wet/snow/ice. Safer to have the driver more engaged in driving when going downhill.
 

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My Accord will "engine brake" on a steep hill on normal cruise if speed gets too far over the setting. My wife's 2009 scion xb would do it when we owned it awhile back too. Its not rocket science.
 

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Cool feature for MT drivers, if you downshift fast enough (within 5 seconds) with cruise engaged, it will re-engage automatically after you've shifted. Found that out on a road trip.
 

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In my 2017 Accord with CVT I shift to "S" when going up or downhill. Uphill to get a bit more kick while going up and to quickly accelerate (Eco mode does not help), equivalent to shifting to 4th on a manual transmission. Then going downhill I also shift to "S" to let the car do some engine braking. My car does not have ACC and I normally don't use cruise control going up or downhill but I do know that the car maintains the set speed going downhill if I use S mode.

As a side note, I have noticed that when going downhill in "S" mode, the car will rev up if I touch the brake pedal as if I had downshifted on a manual.
 
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