FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups 
 ProfileProfile   PreferencesPreferences   Log in to check your private messagesLog in to check your private messages   Log inLog in 
Forum index » Electronix » design
OT: Petrol consumption
Post new topic   Reply to topic Page 4 of 6 [77 Posts] View previous topic :: View next topic
Goto page:  Previous  1, 2, 3, 4, 5, 6 Next
Author Message
Eeyore
electronics forum Guru


Joined: 22 Jun 2006
Posts: 642

PostPosted: Thu Jul 20, 2006 1:40 am    Post subject: Re: Petrol consumption Reply with quote

Rich Grise wrote:

Quote:
But, what's the difference in MPG between, say, Bakersfield and Fresno,
with headlights on and off?

Inconsequential I'd expect. OTOH I've seen significant changes in overall mpg
between summer and winter.

Graham
Back to top
Rich Grise
electronics forum Guru


Joined: 24 Mar 2005
Posts: 3971

PostPosted: Thu Jul 20, 2006 1:41 am    Post subject: Re: Petrol consumption Reply with quote

On Wed, 19 Jul 2006 16:49:53 -0500, Richard Owlett wrote:
Quote:
Eric Jacobsen wrote:

Ya gotta give people _some_ credit for having brain cells.

*WHY*

Have you EVER directed traffic at a fire or accident scene?

I have!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
I was a Fire Police Officer in Ithaca New York Fire Department

Do you understand that otherwise intelligent people have problems
understanding that a 100 ft ladder parked crosswise of their intended
route presents a problem?

And I have even better stories.

Well, heaven's snakes alive, don't keep us in suspenders! ;-)

Please, do tell!

Thanks!
Rich
Back to top
Eeyore
electronics forum Guru


Joined: 22 Jun 2006
Posts: 642

PostPosted: Thu Jul 20, 2006 1:42 am    Post subject: Re: Petrol consumption Reply with quote

Bobo The Chimp wrote:

Quote:
On Wed, 19 Jul 2006 14:35:16 -0700, Eric Jacobsen wrote:

Eric Jacobsen
Minister of Algorithms, Intel Corp.

Huh? You pray with them, in hopes that they might receive Divine Healing?

Well, why not? We've tried everything else! ;-P

Good Luck!
Rich^H^H^H^HBobo

What's ctrl-H on your box btw ?

Graham
Back to top
John Popelish
electronics forum Guru


Joined: 29 Apr 2005
Posts: 1601

PostPosted: Thu Jul 20, 2006 1:48 am    Post subject: Re: Petrol consumption Reply with quote

glen herrmannsfeldt wrote:

Quote:
Now consider the cost in energy to build a car multiplied by the
increased probability of totaling the car in an accident when
the lights are off.

What are your probability numbers on how much chance of an accident in
daylight, with lights on and off? I really doubt anyone has ever done
a controlled statistical experiment. I think having lights on in
daylight just gives insurance companies worm fuzzies, the same way
street lighting does. Both waste power and do little that is actually
useful.

A more fuel efficient means to be noticed in daylight would be to
paint the car bright orange (or yellow and black stripes) and add a
big, snarling, toothy monster face to the grill. How do you think
that would change the odds, compared to the added glint of headlights
on a gray road colored car in bright sunlight?
Back to top
Rich Grise
electronics forum Guru


Joined: 24 Mar 2005
Posts: 3971

PostPosted: Thu Jul 20, 2006 2:02 am    Post subject: Re: OT: Petrol consumption Reply with quote

On Wed, 19 Jul 2006 03:36:24 -0700, Richard Henry wrote:
Quote:
glen herrmannsfeldt wrote:
Eeyore wrote:
(snip)
A/C's another matter - and that *does* take a load of power
from the engine via the compressor.

Last I heard, above about 40mi/h the AC takes less power than
the increased drag of having the windows open.

A secondary effect is the change in engine temperature
with the AC heat from the condenser core going into the radiator.

Last night I drove my wife to the LA airport (about 2 hours). We took
her new car, which as an mpg readout in the instrument panel. On the
way up, with the AC on, we were running about 26-28 mpg. Returning
after dark, with the AC off, we wer getting 31-33 mpg. We were going
65-75 mph both ways, depending on traffic, and hills were trivial
either way (Route 91 from Corona to LAX and return).

But were the windows open? That would also be very interesting, at 65-75
MPH. After dark you not only don't have the AC going, but the air is
cooler anyway - both for the vents, and for the motor cooling.

But, since you have the meter, and such a kewl test track, would you
be willing to do the same thing with the windows open and keep such
good records? I think that'd be noteworthy!

I was out today in mine ('86 Fiero), and got up to 65 for a bit on
the freeway, but had the windows open because my A/C is SNAFU. )-;
On the way back, I found the shortcut through the foothills, which
is much cooler and shadier than the freeway, and I think I made
better time. :-)

Thanks!
Rich
Back to top
pomerado@hotmail.com
electronics forum beginner


Joined: 19 Jun 2006
Posts: 41

PostPosted: Thu Jul 20, 2006 2:07 am    Post subject: Re: Petrol consumption Reply with quote

Rich Grise wrote:

Quote:
But, what's the difference in MPG between, say, Bakersfield and Fresno,
with headlights on and off?

If you are frequently driving between Bakersfield and Fresno, you have
my pity.
Back to top
Rich Grise
electronics forum Guru


Joined: 24 Mar 2005
Posts: 3971

PostPosted: Thu Jul 20, 2006 2:10 am    Post subject: Re: OT: Petrol consumption Reply with quote

On Wed, 19 Jul 2006 12:14:15 +0100, Eeyore wrote:
Quote:
Roger Hamlett wrote:
"Richard Henry" <pomerado@hotmail.com> wrote in message
glen herrmannsfeldt wrote:
Eeyore wrote:

(snip)

A/C's another matter - and that *does* take a load of power
from the engine via the compressor.

Last I heard, above about 40mi/h the AC takes less power than
the increased drag of having the windows open.

A secondary effect is the change in engine temperature
with the AC heat from the condenser core going into the radiator.

Last night I drove my wife to the LA airport (about 2 hours). We took
her new car, which as an mpg readout in the instrument panel. On the
way up, with the AC on, we were running about 26-28 mpg. Returning
after dark, with the AC off, we wer getting 31-33 mpg. We were going
65-75 mph both ways, depending on traffic, and hills were trivial
either way (Route 91 from Corona to LAX and return).
This is quite common. As well as the change from the A/C, the engine runs
more efficiently, when the OAT is lower (within certain limits). In the
UK, on a run I used to do very often, a cool, slightly damp morning,
returned the 'best' economy.

Have you ever noticed that the engine is distinctly more sprightly under some
weather conditions tooo ?


Yes - they seem to like cool, very humid air. I don't know what OAT
means, but I'm guessing it has something to do with the barometer or
the humidity. One time, I got a promotional gimmick from some guy who
wanted to make a million - it was a little plastic bag about 8" long
and about 1" in diameter, that you just laid in your air cleaner thing, on
the "clean" side. I guess it was just some kind of permeable plastic,
with some wet gel inside that just continuously gave off water vapor until
it dried out, in a couple of weeks.

Now, I'm not discounting the placebo effect, but it did seem to make
the car a little peppier - but this was a different car than I have now,
so can't repeat it, and I have no idea where the guy with the little
magic beans went, but it seems that I've read different things that seem
to indicate that introducing water vapor into the combustion chamber
somehow improves something, hopefully efficiency.

Anybody know?

Thanks,
Rich
Back to top
Rich Grise
electronics forum Guru


Joined: 24 Mar 2005
Posts: 3971

PostPosted: Thu Jul 20, 2006 2:11 am    Post subject: Re: OT: Petrol consumption Reply with quote

On Wed, 19 Jul 2006 13:08:24 +0000, Roger Hamlett wrote:

Quote:
I think it has become slightly less noticeable on modern cars and with
modern lubricants and fuel injection, but on older models, there were
days when the engine just wanted to 'sing', and others when it felt like
half the cylinders were missing!. I'd put 90% of it down to the mixture
control on these engines though. Temperature is the big beast in regard
to overall engine 'output'. On light aircraft, you use a slightly 'safe'
factor of 10% loss in take-off performance for every 10C change in air
temperature...

I'd think with an airplane, lift would have a lot to do with it... ;-)

Cheers!
Rich
Back to top
Eric Jacobsen
electronics forum beginner


Joined: 13 May 2005
Posts: 8

PostPosted: Thu Jul 20, 2006 2:12 am    Post subject: Re: OT: Petrol consumption Reply with quote

On Wed, 19 Jul 2006 16:33:23 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote:

Quote:
On Thu, 20 Jul 2006 00:16:18 +0100, Eeyore
rabbitsfriendsandrelations@REMOVETHIS.hotmail.com> wrote:



martin griffith wrote:

On Wed, 19 Jul 2006 22:53:41 +0100, in sci.electronics.design Eeyore
rabbitsfriendsandrelations@REMOVETHIS.hotmail.com> wrote:



Eric Jacobsen wrote:

A lot of guys who do performance tuning on cars with superchargers
still use water injection to cool the air charge under pressure. The
thing I've found really strange is that the optimum juice to use for
this is windshield washer fluid. So what a lot of people do is just
run a pump line from the washer reservoir to the high pressure side of
the supercharger and trigger the pump with a particular boost level.
Works like a champ.

Screenwash often contains ethanol. The ethanol evaporates and absorbs latent
heat, cooling the intake air.

Graham
Eric must be a cool frood, and knows where his towel is

http://www.ericjacobsen.org/icard.htm

LOL ! I like it.

Graham

Looks like Eric and I are neighbors. That's the Intel division I
consulted for when I designed the USB modules.

Follow Chandler Blvd west for about 8 miles and you come to my abode.

...Jim Thompson

Ah, cool! I rarely get down to that end of town these days (work
from home), but perhaps we could grab a beer sometime. They don't
drink themselves, after all... ;)

Eric Jacobsen
Minister of Algorithms, Intel Corp.
My opinions may not be Intel's opinions.
http://www.ericjacobsen.org
Back to top
Mark
electronics forum Guru


Joined: 03 May 2005
Posts: 329

PostPosted: Thu Jul 20, 2006 2:19 am    Post subject: Re: Petrol consumption Reply with quote

Eric Jacobsen wrote:
Quote:
On 19 Jul 2006 07:04:59 -0700, "Mark" <makolber@yahoo.com> wrote:

Now consider the cost in energy to build a car multiplied by the
increased probability of totaling the car in an accident when
the lights are off.

-- glen

this is the correct answer, the fuel cost to run the headlights is MUCH
lower compared to the "probability cost" of reducing the chances of
having an accident.

Mark

Uh, only assuming that one would be as likely to drive in the dark if
the headlights were not equipped.

Do you try to fly your car even though it doesn't have wings?

Ya gotta give people _some_ credit for having brain cells.


I'm talking about even in the daytime...


the reduced probability of an accident in the daytime due to the
increased visability of your vehicle is well worth the small amount of
fuel it takes to run the lights..
Back to top
Eeyore
electronics forum Guru


Joined: 22 Jun 2006
Posts: 642

PostPosted: Thu Jul 20, 2006 2:22 am    Post subject: Re: OT: Petrol consumption Reply with quote

Rich Grise wrote:

Quote:
On Wed, 19 Jul 2006 13:08:24 +0000, Roger Hamlett wrote:

I think it has become slightly less noticeable on modern cars and with
modern lubricants and fuel injection, but on older models, there were
days when the engine just wanted to 'sing', and others when it felt like
half the cylinders were missing!. I'd put 90% of it down to the mixture
control on these engines though. Temperature is the big beast in regard
to overall engine 'output'. On light aircraft, you use a slightly 'safe'
factor of 10% loss in take-off performance for every 10C change in air
temperature...

I'd think with an airplane, lift would have a lot to do with it... Wink

There are special recommendation for operating aircraft in 'hot and high'
conditions where the air is significantly thinner.

One Lufthansa 747 was notably thought to have got their hot and high
calculations wrong when departing Nairobi, Kenya but it turned out to be a
leading edge flaps issue.
http://dnausers.d-n-a.net/dnetGOjg/201174.htm

Graham
Back to top
Jim Thompson
electronics forum Guru


Joined: 06 May 2005
Posts: 5440

PostPosted: Thu Jul 20, 2006 2:26 am    Post subject: Re: OT: Petrol consumption Reply with quote

On Wed, 19 Jul 2006 19:12:32 -0700, Eric Jacobsen
<eric.jacobsen@ieee.org> wrote:

Quote:
On Wed, 19 Jul 2006 16:33:23 -0700, Jim Thompson
To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote:

[snip]

Looks like Eric and I are neighbors. That's the Intel division I
consulted for when I designed the USB modules.

Follow Chandler Blvd west for about 8 miles and you come to my abode.

...Jim Thompson

Ah, cool! I rarely get down to that end of town these days (work
from home), but perhaps we could grab a beer sometime. They don't
drink themselves, after all... ;)

Eric Jacobsen
Minister of Algorithms, Intel Corp.
My opinions may not be Intel's opinions.
http://www.ericjacobsen.org

I work from home, also.

Where do you abode? Looks like McDowell Mountain Ranch? My youngest
son and family used to live on 106th Way, north of Thompson Peak.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
Back to top
Jeff L
electronics forum beginner


Joined: 04 Sep 2005
Posts: 47

PostPosted: Thu Jul 20, 2006 2:40 am    Post subject: Re: Petrol consumption Reply with quote

"glen herrmannsfeldt" <gah@ugcs.caltech.edu> wrote in message
news:YYidnbRsnsOUZCDZnZ2dnUVZ_qudnZ2d@comcast.com...
Quote:
Jeff L wrote:
(snip)

Since no one else calculated it, here goes (not including other lights
such
as marker and tail lamps, which are typically about 5W a piece (non LED)
adding to about 35W on a typical car):

Gasoline = ~32,000 kj/l
Engine efficiency (avg, not best case) = 15%
Headlamp power = 55W each X 2
Wiring losses = 3%
Alternator eff = 95%
Belt losses driving alternator = 15%
1 kWh = 3600 kj

Energy needed to light headlights for 1 hour = 0.110 kW => 396 kj/h

Energy needed to light headlights for 1 hour = 0.110 kWh => 396 kj
Energy is power x time. or

Power needed to light headlights = 0.110 kW => 396 kj/h

Yes, oooooopppppps, gotta stop posting at 4:00 AM! The numbers still work
out.



Quote:

Adding alternator losses gives: 416.84 kj/h
Adding wiring losses gives: 429.73 kj/h
Adding belt losses gives: 505.57 kj/h
Adding engine efficiency losses: 3,370.46 kj/h

Which gives 0.105 l of fuel consumed per hour.

Interesting, that means with the average car, between 300 and 600 l of
fuel
is consumed in just lighting the head lamps over the car's life!

Now consider the cost in energy to build a car multiplied by the
increased probability of totaling the car in an accident when
the lights are off.

-- glen


I wouldn't worry about that small amount of fuel, and besides most cars have
mandatory DRL's (daytime running lights, which are run at reduced power).

Warming up an engine uses way more fuel. For example warming up from
sitting all night at say 10 deg C, my old 2.8L Camaro with multi port fuel
injection would take 2 - 3 L in the first 5 km (yes, I actually managed to
measure this (ALDL data, and confirmed with an *emergency* fuel pump and
tank)), then start sipping fuel. eg I would commonly get about 100km per 8 -
9 L when driving down the highway at 140 km/h, with a few higher speed
bursts when dropped down to 4th gear. Mixed city driving was generally 10 to
12 L per 100 km, and driving granny mode (100 km/h, using the highest gear
as soon as possible, and *normal* acceleration) down the highway could get
down to the 7 l per 100 km mark.


Generally, with the above calc's it looks like a car will burn 0.95 L per
hour, per 1 kw load, assuming that the energy is not drawn during
deceleration

There are a ton of other things that use power in a car also, such as (with
estimates of energy usage):
- heater blower ~ 300W on full
- window defrost ~ 300W for ~20 min
- Dash lights ~30W
- exterior lights ~35 W
- Stereo ~10 to 50W
- Cooling fan 200W to 400W intermittent
- Fuel Pump ~50 - 75W average
- Ign system 30 to 50W
- emission pump if equipped - 200 - 300 W
- MAF sensor 75 to 350W
- Injectors and controller 50 to 150W
- power accessories - large draw that is intermittent, so little energy over
all

Mechanical loads
- water pump - 500 to 4000 W, generally several kW on the highway!
- power steering pump - 100 to 3000W
- belts - 50 to 400W
- emission pump 300 to 1000W
- idler pulley - 5 to 50W
- air conditioning compressor - 750 to 7500 W dependant on size and design
- Valve train losses - this is large - A company that builds racing valve
springs built a machine to spin a typical SBC chev V8 up to 8000 RPM. The
motor had no crank, just valve train parts, and they needed an electric
motor with something like 40 HP!
- Oil Pump - ???

Other losses:
- Brake drag
- Tire friction (can be substantial)
- Wheel bearing friction
- Transmission losses and differential losses, generally 10 to 15%,
generally higher at lower power levels due to the energy needed to overcome
friction, also can be higher if it's an automatic
- Oil viscosity drag
Back to top
Jeff L
electronics forum beginner


Joined: 04 Sep 2005
Posts: 47

PostPosted: Thu Jul 20, 2006 2:50 am    Post subject: Re: OT: Petrol consumption Reply with quote

"Roger Hamlett" <rogerspamignored@ttelmah.demon.co.uk> wrote in message
news:08xvg.41754$sz1.36940@newsfe6-gui.ntli.net...
Quote:

"Richard Henry" <pomerado@hotmail.com> wrote in message
news:1153330007.557114.310290@75g2000cwc.googlegroups.com...

Jerry Avins wrote:

I kept the ignition timing on the edge of too advanced in my '53 Ford
F-head. I could just make it knock a little between 35 and 45 mph when
floored in third gear. That is, except on humid days. Fog was just like
retarding the timing. The engine ran smoother, but with less oomph.

Some old military aircraft engines injected water to make the engines
run better.
Not just to 'make them run better'. They could run with higher boost
pressures, and/or the ignition more advanced (just like the car in the
above quote), without knocking. Adding water is not really quite like
retarding the timing. It has a whole 'series' of effects, but the main
ones are cooling the mixture, and cooling the combustion chamber. On the
car, the mixture, and induction pressures used were fixed, but on most
aircraft, the mixture can be adjusted, and with a supercharger, you can
run with more boost to get more total power.
It was tried as early as the 1920's, by Sir Harry Ricardo (he also came up
with the 'octane' designation for fuels), but first came into 'common' use
on the latter supercharged engines in WWII, where a 'combat power'
setting, used this. Both UK, and US aircraft used this. You actually can
get higher fuel economy with this. The problem of course is the need to
supply water...

There is one more effect from the water - during it's cooling of the engine,
it's absorbing energy, and thus expanding, potentially producing usable
energy from waste heat. See the posts from a few months back on the 6 stroke
engine in a.b.s.e. The biggest effect, I would believe is the cooling of the
combustion charge enough to prolong detonation and allow larger charges or
more advanced timing.



Quote:

Best Wishes

Back to top
Paul Hovnanian P.E.
electronics forum Guru


Joined: 29 Apr 2005
Posts: 583

PostPosted: Thu Jul 20, 2006 3:17 am    Post subject: Re: OT: Petrol consumption Reply with quote

Rich Grise wrote:
Quote:

On Wed, 19 Jul 2006 12:14:15 +0100, Eeyore wrote:
Roger Hamlett wrote:
"Richard Henry" <pomerado@hotmail.com> wrote in message
glen herrmannsfeldt wrote:
Eeyore wrote:

(snip)

A/C's another matter - and that *does* take a load of power
from the engine via the compressor.

Last I heard, above about 40mi/h the AC takes less power than
the increased drag of having the windows open.

A secondary effect is the change in engine temperature
with the AC heat from the condenser core going into the radiator.

Last night I drove my wife to the LA airport (about 2 hours). We took
her new car, which as an mpg readout in the instrument panel. On the
way up, with the AC on, we were running about 26-28 mpg. Returning
after dark, with the AC off, we wer getting 31-33 mpg. We were going
65-75 mph both ways, depending on traffic, and hills were trivial
either way (Route 91 from Corona to LAX and return).
This is quite common. As well as the change from the A/C, the engine runs
more efficiently, when the OAT is lower (within certain limits). In the
UK, on a run I used to do very often, a cool, slightly damp morning,
returned the 'best' economy.

Have you ever noticed that the engine is distinctly more sprightly under some
weather conditions tooo ?


Yes - they seem to like cool, very humid air. I don't know what OAT
means, but I'm guessing it has something to do with the barometer or
the humidity. One time, I got a promotional gimmick from some guy who
wanted to make a million - it was a little plastic bag about 8" long
and about 1" in diameter, that you just laid in your air cleaner thing, on
the "clean" side. I guess it was just some kind of permeable plastic,
with some wet gel inside that just continuously gave off water vapor until
it dried out, in a couple of weeks.

Now, I'm not discounting the placebo effect, but it did seem to make
the car a little peppier - but this was a different car than I have now,
so can't repeat it, and I have no idea where the guy with the little
magic beans went, but it seems that I've read different things that seem
to indicate that introducing water vapor into the combustion chamber
somehow improves something, hopefully efficiency.

Anybody know?

http://en.wikipedia.org/wiki/Water_injection_%28engines%29

--
Paul Hovnanian mailto:Paul@Hovnanian.com
------------------------------------------------------------------
How do I set a laser printer to stun?
Back to top
Google

Back to top
Display posts from previous:   
Post new topic   Reply to topic Page 4 of 6 [77 Posts] Goto page:  Previous  1, 2, 3, 4, 5, 6 Next
View previous topic :: View next topic
The time now is Sat Jun 24, 2017 1:47 am | All times are GMT
Forum index » Electronix » design
Jump to:  

Similar Topics
Topic Author Forum Replies Last Post
No new posts Current consumption of MP3 player with OLED display Jon D Equipment 13 Tue Jun 27, 2006 1:07 pm
No new posts Circuit Power Consumption phaeton Basics 13 Mon Jun 26, 2006 5:44 pm
No new posts led power consumption eeh design 3 Sat Jun 24, 2006 8:21 am
No new posts Analog versus digital: power consumption Joerg design 11 Tue May 16, 2006 3:03 am
No new posts dc power consumption johnmclaren_99@yahoo.com Basics 7 Fri Mar 31, 2006 4:32 am

Copyright © 2004-2005 DeniX Solutions SRL
Other DeniX Solutions sites: Unix/Linux blog |  Unix/Linux documentation |  Unix/Linux forums |  Medicine forum |  Science forum  |  Send and track newsletters


Powered by phpBB © 2001, 2005 phpBB Group