Honda Car Forum

On Fri, 09 Sep 2005 14:21:40 -0400, "Elmo P. Shagnasty"
<elmop@nastydesigns.com> wrote:

>In article <jae3i1t4su6d9t906l762eqek64nj8vo48@4ax.com>,
> flobert <nomail@here.NOT> wrote:
>
>> >ahem. Your BEST mileage will be when using cruise control.
>>
>> You'd think so, but experimentally, in a lot of different cars doing
>> economy runs, its not. Cruise control is just to keep the car at a
>> constant speed, no to do it efficiently.
>
>So you're keeping your throttle at exactly the same position, manually,
>and if you go up or down a hill and your speed changes dramatically, so
>be it?

I say up front i ahven't used cruise control in years, except for once
last week. My vehicles don't have it, i don't use it. I used it on my
wifes work van, a 96 T+C. Before this, my last experiance was with a
03 buick century back in 03 (a rental car).

Basically, whenevre it droped below the set speed, it opened the
throttle to what felt like 20%, and carried on until the set speed was
reached. Personally, i'd fluctuate a bit more, run it 3 or so over,
let it run 3 or so under, and repeat. The vehicle seemed to surge as
well, as it moved into acceleration mode. and it never went over about
2500rpm, avoiding the peak torque area (which is the most efficient
area)) although whether this was more a fact of the cruise control, or
the slushbox, i don't know.

These large and drequent instances of throttle usage are not efficient
However, the wife loves the cruise control. i've asked her to make a
not of how far and how much fuel she used in the van today, and when
we do the route again, i'lm going to go with her, and drive as i
normally do, to compareThat'll be at least a week away though.

On Fri, 09 Sep 2005 12:34:22 -0400, flobert <nomail@here.NOT> wrote:

>On Wed, 07 Sep 2005 13:11:41 -0400, "Elmo P. Shagnasty"
><elmop@nastydesigns.com> wrote:
>
>>In article <4nh3v2-pso.ln1@new.helps.com>, jdhoward@helps.com wrote:
>>
>>> To get that economy, I use no air
>>> conditioning, no cruise control
>>
>>ahem. Your BEST mileage will be when using cruise control.
>
>You'd think so, but experimentally, in a lot of different cars doing
>economy runs, its not. Cruise control is just to keep the car at a
>constant speed, no to do it efficiently.

Cruise control will be an obvious help for those who cannot keep from
moving their foot up and down on the throttle on level ground without
a headwind. However, people who can keep their speed on level ground
within a couple of miles per hour can save gas when going up hill and
into headwinds. The cruise control will attempt to maintain speed
come hell or high water, even to the point of shifting down. This is
when a person with the ability to "feel" the car can get better
mileage by backing off slightly to avoid the balls to the wall effort
by the cruise. Under normal circumstances on the highway I will use
the cruise. When I get into the mountains I turn it off.

Dick

Dick wrote:

> Cruise control will be an obvious help for those who cannot keep from
> moving their foot up and down on the throttle on level ground without
> a headwind. However, people who can keep their speed on level ground
> within a couple of miles per hour can save gas when going up hill and
> into headwinds. The cruise control will attempt to maintain speed
> come hell or high water, even to the point of shifting down. This is
> when a person with the ability to "feel" the car can get better
> mileage by backing off slightly to avoid the balls to the wall effort
> by the cruise. Under normal circumstances on the highway I will use
> the cruise. When I get into the mountains I turn it off.

All good points.

I think another factor is the use of the "resume" and "accel" functions.
The first few times I used the cruise on my '93 Accord, hitting "resume" at
a speed significantly lower than the set speed resulted in the equivalent of
a somewhat heavy foot (well, heavier than mine, and I'm not exactly an easy
going driver). "Accel" produced a similar result. For that reason, when I
accelerate to get back to my set speed, I press the gas pedal myself to not
rush it, and then when I am at or very close to my previously set speed,
then I "resume". To "accel", again I press the gas pedal myself to not rush
it, and when I reach my intended speed, I "cancel" and then "set" it to the
new speed. I found that this practice increased my gas mileage by a few
miles per gallon.

Of course, this cruise control behaviour may vary among different car
manufacturers.

On Fri, 9 Sep 2005 16:55:01 -0400, High Tech Misfit <me@privacy.net>
wrote:

>Dick wrote:
>
>> Cruise control will be an obvious help for those who cannot keep from
>> moving their foot up and down on the throttle on level ground without
>> a headwind. However, people who can keep their speed on level ground
>> within a couple of miles per hour can save gas when going up hill and
>> into headwinds. The cruise control will attempt to maintain speed
>> come hell or high water, even to the point of shifting down. This is
>> when a person with the ability to "feel" the car can get better
>> mileage by backing off slightly to avoid the balls to the wall effort
>> by the cruise. Under normal circumstances on the highway I will use
>> the cruise. When I get into the mountains I turn it off.
>
>All good points.
>
>I think another factor is the use of the "resume" and "accel" functions.
>The first few times I used the cruise on my '93 Accord, hitting "resume" at
>a speed significantly lower than the set speed resulted in the equivalent of
>a somewhat heavy foot (well, heavier than mine, and I'm not exactly an easy
>going driver). "Accel" produced a similar result. For that reason, when I
>accelerate to get back to my set speed, I press the gas pedal myself to not
>rush it, and then when I am at or very close to my previously set speed,
>then I "resume". To "accel", again I press the gas pedal myself to not rush
>it, and when I reach my intended speed, I "cancel" and then "set" it to the
>new speed. I found that this practice increased my gas mileage by a few
>miles per gallon.
>
>Of course, this cruise control behaviour may vary among different car
>manufacturers.

Absolutely. I should have thought to mention that as well.

Dick

In article <efn3i15adugoiooa593scpffimo9mth3m7@4ax.com>,
flobert <nomail@here.NOT> wrote:

> >So you're keeping your throttle at exactly the same position, manually,
> >and if you go up or down a hill and your speed changes dramatically, so
> >be it?
>
> I say up front i ahven't used cruise control in years, except for once
> last week. My vehicles don't have it, i don't use it. I used it on my
> wifes work van, a 96 T+C. Before this, my last experiance was with a
> 03 buick century back in 03 (a rental car).

So you're saying you have very little experience with cruise control.

I also noticed that you avoided answering my question, so I'll ask it
again:

So you're keeping your throttle at exactly the same position, manually,
and if you go up or down a hill and your speed changes dramatically, so
be it?

Is that what you're doing when you drive, to avoid the throttle
movements that are "inefficient"?

In rec.autos.makers.honda Elmo P. Shagnasty <elmop@nastydesigns.com> wrote:
> So you're keeping your throttle at exactly the same position, manually,
> and if you go up or down a hill and your speed changes dramatically, so
> be it?

My Datsun roadster had a manual throttle lock. I'd get to cruising speed,
pull the knob, and there I was... Mechanical Cruise Control.

Same thing for a few bucks on motorcycles, some sort of flip-lock on the
throttle. http://www.rattlebars.com/mtz/invisible.html

On roughly level ground, it worked just fine. A freeway overpass would
knock some speed off, and down the other side would overspeed, but overall
it was a pretty decent thing.

Logically, one might do the same thing with an electronic cruise control.
As my Civic starts up a grade, I have two choices: I can let the cruise
control maintain the speed, including over 5000 RPM, or I can kill the
cruise control. If it's a long grade, I let it run whatever RPM it wants.
If it's a minor grade, I kill it.

If there was some tolerance, allowing the speed to drop, programmed for a
typical overpass, cruise control could be more efficient. People without
cruise control are probably losing speed at that point anyway, so they
would never notice.

--
---
Clarence A Dold - Hidden Valley (Lake County) CA USA 38.8,-122.5

In article <dft65s$4bs$3@blue.rahul.net>, dold@XReXX2003X.usenet.us.com
wrote:

> My Datsun roadster had a manual throttle lock. I'd get to cruising speed,
> pull the knob, and there I was... Mechanical Cruise Control.
>
> Same thing for a few bucks on motorcycles, some sort of flip-lock on the
> throttle. http://www.rattlebars.com/mtz/invisible.html
>
> On roughly level ground, it worked just fine. A freeway overpass would
> knock some speed off, and down the other side would overspeed, but overall
> it was a pretty decent thing.
>
> Logically, one might do the same thing with an electronic cruise control.

Oh, I agree. I would like the option to be a throttle lock instead of a
cruise lock.

And with computers, it ought to be that easy.

On Fri, 09 Sep 2005 18:25:55 -0400, "Elmo P. Shagnasty"
<elmop@nastydesigns.com> wrote:

>In article <efn3i15adugoiooa593scpffimo9mth3m7@4ax.com>,
> flobert <nomail@here.NOT> wrote:
>
>> >So you're keeping your throttle at exactly the same position, manually,
>> >and if you go up or down a hill and your speed changes dramatically, so
>> >be it?
>>
>> I say up front i ahven't used cruise control in years, except for once
>> last week. My vehicles don't have it, i don't use it. I used it on my
>> wifes work van, a 96 T+C. Before this, my last experiance was with a
>> 03 buick century back in 03 (a rental car).
>
>So you're saying you have very little experience with cruise control.

I'm saying i have limited experiance, but with that, i pay a lot more
attention to what its doing - its not something i take for grated, and
ignore as a backgroud part of driving'

>
>I also noticed that you avoided answering my question, so I'll ask it
>again:
>
>So you're keeping your throttle at exactly the same position, manually,
>and if you go up or down a hill and your speed changes dramatically, so
>be it?

no, i'm not. If you read what I said, I vary the cars speed, work with
the grade (and with the road thats comming up - something NO cruise
control can do) anticipate, etc.

Cruise control programming is very simple
10 IF speed<set THEN throttle++ ELSE throttle = 0
20 goto 10

Thats putting how i've seen cruise control operation to be, rendered
into 20-odd year old Basic. If the programming is more conplex, then
it certainly doesn't come across in the driving experiance.

>
>Is that what you're doing when you drive, to avoid the throttle
>movements that are "inefficient"?

To drive efficiently, you must drive smoothly, with no sudden speed
changes, and in harmony with the othre road users around you. A cruise
control takes no notice of any enviroment except the one its driving
over at that second, and has no way of detecting other road users. It
in no way attempts to use the engine most efficiently, so HOW can it
be driving most efficiently?

flobert wrote:
> On Wed, 07 Sep 2005 13:11:41 -0400, "Elmo P. Shagnasty"
> <elmop@nastydesigns.com> wrote:
>
>
>>In article <4nh3v2-pso.ln1@new.helps.com>, jdhoward@helps.com wrote:
>>
>>
>>>To get that economy, I use no air
>>>conditioning, no cruise control
>>
>>ahem. Your BEST mileage will be when using cruise control.
>
>
> You'd think so, but experimentally, in a lot of different cars doing
> economy runs, its not. Cruise control is just to keep the car at a
> constant speed, no to do it efficiently.


i was kinda disappointed in the mileage my 98 civic CX got going from LA
to laughlin nevada and back.

if i would have taken it easy and cruised with traffic at 70-75mph, i
might have gotten more than my usual 32mpg.

but no- i had a lead foot. some of it wasnt my fault.. some grades are
so steep i had to drop it into fourth and floor it just to keep at
80mph. 5th gear was useless, the car couldnt keep up. speedo kept
dropping, even with it floored.

and of course, i had the A/C blasting in that 114 degree desert heat,
too. the mojave desert gets damned hot during the day.

so to reiterate: thats uphill, several thousand foot climbs (2000-5000
feet at a time), A/C blasting, pedal to the metal in 4th gear, doing
80mph uphill. and the temp gauge stayed below halfway! thank gawd for
mobil1 5w30.

downside? 25mpg.

In article <u0q4i1huh7i7rt2oj89sccafur2jipfipr@4ax.com>, flobert <nomail@here.NOT> wrote:

>To drive efficiently, you must drive smoothly, with no sudden speed
>changes, and in harmony with the othre road users around you. A cruise
>control takes no notice of any enviroment except the one its driving
>over at that second, and has no way of detecting other road users. It
>in no way attempts to use the engine most efficiently, so HOW can it
>be driving most efficiently?

I can think of at least one possible way *if* the car is an
automatic. It is possible (though I do not know for a fact) that
the OEM could factor in the CC in the torque converter (TC) lockup
routine. Generally the TC locks up at a certain min rpm and for a
range of throttle positions. It might be programmed to note that if
CC is engaged, throttle-based drivability concerns will not be as
big a deal at lower rpm settings. Thus it might lock it up at
non-normal speeds resulting in a more efficient transmission.

Anyway, it has been my experience that CC probably beats my mileage.
But one factor may be that if I have CC engaged, I'm driving slower
than I would otherwise.

As to the modulating throttle, I think it is a fallacy that this
markedy decreases MPG, unless done so *aggressively*. At
least in a manual where the TC doesn't come into play. Contrary to
what you might infer from your high school driving instruction, an
engine is actually more efficient at higher (but not max) throttle
setting. Accelerating doesn't consume more fuel, braking does!
(well, accel does, but it just stores it in the kinetic energy of
the car where it is available for later use). And yeah, faster
driving means higher rpm and air drag. Both of these result in
increased frictional losses.