One reason DRLs shouldn't be opposed...

By giving Federal regulators an issue to chew on for 15 years and
counting, thus taking regulators' attention off other aspects of GM's
behavior. Equipping all their cars with DRLs also gives them a platform
on which to stand and crow about how progressive and safety-minded they
are.

Sounds like a conspiracy theory, doesn't it? Of course it does. Dig
through the correspondence between GM and NHTSA over the last 15 years and
see for yourself.

DS

 

That is true, but that doesn't address the question -- it answers the
question of why GM hammered away at NHTSA from 1989 through 1995 to get
NHTSA to *permit* DRLs, which Canada mandated on 1/1/90. Interestingly,
Transport Canada (Canada's equivalent of NHTSA) was going to mandate
European-type DRLs which could not possibly have created any glare
problems and would have used relatively little electricity. GM didn't want
to add a new lighting device, and so railroaded TC into allowing the high
beam and other "cheap and nasty" DRL implementations. Once TC acquiesced
to GM's demands, GM turned around and started hammering on NHTSA to do
likewise.

For this among other reasons, it is spurious to use DRL results seen
outside North America as justification for DRLs in North America -- the
implementations are hugely different.

DS

 

OK, I'll start stopping cars and start removing them... Let's all start
doing that...

 

Why?

 

Many things on a modern car are bigger energy drains than DRL's. You've
mentioned stereo's, A/C etc. The point is the energy consumption is a weak
reason to use for not installing them (DRL's) in the first place. And if
energy consumption is the point of this argument, I'm sure we could all
think of many other things to lower fuel consumption than eliminating DRL's.
By the way I'm not for or against DRL's, I really couldn't care less I just
think this "wastes gas and causes excess pollution" is ridiculous.

 

It's not an urban legend, but the description was a little garbled and
was out of date -- the problem isn't actual emissions, it's misfire
detection. I couldn't find an authoritative description, though I did
find

http://www.bergen.org/AAST/Projects/ES/TA/prestech2.html

at a vocational school, which corresponds with what I've read
elsewhere.

The basic problem is that misfire detection is hard. Detecting a
spark plug that wasn't sparking would be easy (just look for
unreasonable voltages on firing), but if, for some reason, the plug
fires but the mixture doesn't, this won't spot it. So, an
accelerometer is used on the crankshaft.

Unfortunately, driving on rough ground can cause crankshaft speed
fluctuations that mimic a misfire. On an automatic transmission, the
computer can respond by releasing the lockup torque converter and
seeing if the misfire goes away before reporting it; it can't do this
with a manual.

But, I think the misfire detection specs have been loosened up in
recent years (which is corroborated but not confirmed by
http://www.obdiicsu.com/Studies/2002CaseStudies/Misfire/Misfire.html);
Dan is a lot more up to date on regs than I am and no doubt knows the
real answer on that.

 

Dan, did you follow the original posters link? I did. In the calculations,
they used 55w headlights as daylight running lights. This is incorrect as
I'm sure you are aware DRL's use much lower watt lights than this, and many
new cars use parking lights now. I don't dispute that it will require more
energy than no lights at all, I maintain that it is insignificant and a non
factor when discussing fuel economy and emissions.

 

Someone did the calculation that I've always wanted to see. The result
This makes ZERO sense. How is turning on light going to cost gas?
Answer, it's not. Your engine does not run any harder when your
lights are on. Your alternator is going to spin like it always does,
expending its extra power that it creates into heat. Now, when you
have DRL, instead of wasting the power it's making, the power will
actually be used to light the bulb.

 

I've seen plenty of people drive with no lights on at night in the city well
before DRL's.

 

"> Go back and read the first post in the thread, which has the power

I did. I suggest you do the same.

 

This IS a load of crap. How is the alternator causing the engine to
run harder? Answer, it's not. You're right, electrical energy
isn't free, as the excess of energy from the alternator is turned into
heat. Alternators also have electronic from preventing from
overcharging the battery, so it's has power "in reserve" so to speak.
Your engine runs no harder if you have zero electrical components on,
or every single one of them. The only accessory which consumes gas (I
don't consider a water pump an accessory, it's a necessity) is A/C.
If you really want to save gas, ban auto air conditioning.

Now you may ask, what's the difference? Well, when you turn the AC
on, it causes the AC clutch to engage, which causes the compressor to
compress. It directly robs power from the engine to run that
compressor. Just like when you were a kid you had one of those lights
which ran off of the tire. The little generator caused drag on the
tire (engine).

But the alternator is just a spinning motor, and it's going to spin
whether you have DRLs on or off.

 

The engine DOES have an additional load on it when the lights are on, to
turn the alternator under load, keeping the battery charged. There is no
"wasting the power" as in your scenario.

 

Are you serious? Do you really think that electricity comes for free?
Every last little bit of electrical load applied -- every single
electrical device switched on -- causes the alternator to be harder to
turn.

That's simply wrong. Start your car. Let it idle. Listen closely to it.
Switch on the high-beam headlamps -- you can HEAR and FEEL the engine bog
under the extra load before the idle air control increases the idle speed
to compensate.

So does the alternator.

It's going to spin whether the DRLs are on or off, but it's harder to spin
when the DRLs are on. That's just plain old physics -- an alternator's job
is to convert mechanical energy into electrical energy. If you can come up
with an alternator that's equally easy to spin when there's an electrical
load on it as it is to spin with no load, go IMMEDIATELY and patent it --
you'll have invented free energy *and* the perpetual-motion machine all at
once.

DS

 

So you read the original article, you read the link, you saw and followed
the mathematical calculation of how many gallons of gasoline are used by
DRLs -- and you're still going to sit there and say they don't use any
significant amount of energy. OK, that's fine, but your statement amounts
to "I've already decided my opinion, so stop trying to confuse me with
facts."

 

You obviously do not understand how alternators work. They don't just sit
there "making power" all the time and "wasting it" or "expending it into
heat" when there's no demand.

 

Yep. And it was easier for cops to spot 'em and cite 'em before DRLs.

 

This is, in fact, incorrect.

Did you get an EE degree from a correspondance course? If so, who did
the tests for you?

 

Larry,

You're wrong here on this one. If the alternator is providing a higher
current output, then the force required to turn it will be greater. This is
from the increase in the opposing magnetic force generated by the higher
current in the armature and/or field windings.

If turning on the light did not consume additional energy then you would be
breaking the law of the conservation of energy...

If you have access to a gasoline powered AC generator (similar in design to
the alternator) you can do a simple test by filling the gas tank, firing up
the generator, and leaving it unloaded and then seeing how long it runs.
You could then do the same experiment after putting a load on the generator.
You'll find the same tank of gas does not last quite as long.

In fact, you can turn the load "on" while the generator is running and if
it's heavy enough you'll hear the generator slow momentarily and then come
back up to speed due to the increased load.

Bob

 

Actually, it's quite correct. The most common DRL implementations in North
America are, in descending order:

1) High beams at 65% - 70% duty cycle
2) Low beams at 100% duty cycle
3) Low beams at 75% to 90% duty cycle
4) Front turn signals burning full time at 100% duty cycle
5) Low and high beams in series

The per-car DRL system power consumption for these systems, in the same
order, is:

1) 80w to 100w
2) 90w to 178w
3) 67w to 117w
4) 54w to 108w
5) 95w to 149w

So the article's assumption was right on target.

Nope. Parking lamps are not allowed as DRLs under US or Canadian
regulations. The ones you're thinking of use the front *turn signals*
burning full time. That's system (4) in the list.

But you're incorrect. The maths in the linked article are proper and don't
lie, but even if for some reason you think otherwise, consider this: US
FECT (Federal Emission Certification Tests) must be passed by each
individual model in order for that model to be legally sold. One
body-engine-transmission-diff-tire-year combo is "one model". The FECT
protocol requires that vehicles be configured exactly as they are produced
for public consumption, so that emissions characteristics measured are
representative of the cars that are actually sold onto the roads.
Emissions collected during FECT are used to calculate that model's fuel
economy for CAFE (Corporate Average Fuel Economy) test purposes.

General Motors asked for and received permission from EPA to run their
vehicles through FECT *with the DRLs deactivated*, on the grounds that
DRLs are not required by US law. However, every new GM vehicle comes with
DRLs which GM will not help you disable. Now why would GM ask for that
permission if DRLs did not have a significant effect on emissions and
mileage?

DS

 

True and irrelevant.