[vertrkr]

There are a few reasons for this, here's the two main ones. Honda is very sensitive about mpg averaged over their whole fleet for CAFE qualifications and so forth. When you have your lights on it actually reduces your mpg by about a 1/10th mpg as the engine has to work slightly harder turning the extra load on the generator/altenator. I also learned Honda only charges the battery during decceleration, apparently they've been doing this for the past 15 years, pretty smart. The other reason is DRLs have never been proven to make a difference as a safety feature.

 

[laserfan]

Hmmm, I didn't know they were building alternators with air conditioner compressor-type clutches these days. That can be the only way they could control the alternator's drag on the engine, yes?

 

[vertrkr]

Hmmm, I didn't know they were building alternators with air conditioner compressor-type clutches these days. That can be the only way they could control the alternator's drag on the engine, yes?

I have no idea how they do it but I'd think it would be more electronically controlled. The extra load would only be present when they tell it to charge the battery so I don't think a clutch would be needed.

 

[Whaleya]

I disagree

If Honda is concerned about MPG a bigger draw is the heated windshied that can't be turned off and a hundred other items on the typical truck or car that affects MPG much more then DRL. For example, how about the lack of insulation so the A/C unit is trying to keep a giant tin can cool in the blistering heat?

DRM have been proven and are required in many countries and on many roads within the US as well.

My guess is that someone at Honda doesn't like DRL, but instead of saying this, Honda has come up with some feable excuses instead.

 

[vertrkr]

I disagree
If Honda is concerned about MPG a bigger draw is the heated windshied that can't be turned off and a hundred other items on the typical truck or car that affects MPG much more then DRL. For example, how about the lack of insulation so the A/C unit is trying to keep a giant tin can cool in the blistering heat?

I think they do what they can within reason or rather without making the truck too expensive. Certainly they could make the whole thing out of carbon fiber but that's an extreme example. I'd love to get better gas milage but not at the expensive of having to pay more, 35k is plenty. AS for the windshield heater element, that only comes on with the outside temp is like 35 degrees. Who knows if it stays on after you start driving but I'd guess it would turn off after a bit. I'll try to find that out.

As for DRLs, I don't agree with Honda on the safety aspect of them, so I'm going to add my own. Either from Hamsar or I'm investigating what it would take to get the stock ones from Honda that they ship with the Canadian models. Pretty sure I'm going to have to buy the parts from a Canadian dealer, I'm trying to find out what's needed to convert the US model to Canadian for the DRLs.

 

[laserfan]

I absolutely cannot imagine an electrical accessory drawing enough current to impact the engine operation, unless of course something is amiss. The alternator, like the a/c compressor when running, by virtue of the belt(s) puts a drag on the engine and THAT affects the engine performance and MPG, just like wind or tire pressure or bed loading or anything else that drags on the engine.

But DRL affecting spark? I don't think so, at least not (even) to the tune of 1/10 mpg.

But I'm willing to buy the argument if the alt. has a clutch or magnetic brake or something.

Hey Whaleya, do you recognize this? "B as in B, and S as in S!!!!" (from an ex-fellow MNesotan)

 

[vertrkr]

But DRL affecting spark?

Spark? did I miss something here? not sure anyone mentioned spark or what you mean by that. At anyrate, don't shoot the messenger, I'm just relaying info when I asked the quesiton to a senior Honda engineer.

 

[swampler]

My guess would be that the electrical accessories require more power, thus causing an increased load on the alternator. This in turn requires more engine power to keep the alternator charging at the appropriate level.

 

[The Great Tristano]

I absolutely cannot imagine an electrical accessory drawing enough current to impact the engine operation, unless of course something is amiss. The alternator, like the a/c compressor when running, by virtue of the belt(s) puts a drag on the engine and THAT affects the engine performance and MPG, just like wind or tire pressure or bed loading or anything else that drags on the engine.

Every current affects engine operation, however unnoticeable it may be. Horsepower is nothing more than an obscure measurement of power, so if an engine produces 255HP, every load carried by the engine has to tap into that same 255HP. I agree that there wouldn't be a huge difference, given the other mechanisms like A/C or power steering, which would certainly overshadow the piddly little draw of DRL.

However, DRL is just such a diverted solution to safety issues. With people yapping on their cell phones, steering with their knees, and fiddling with the DVD player to appease their "A.D.D." kids...is it really that drivers can't see other cars, or is it that one or the other isn't looking?

 

[MountainBiker]

Check this out: If daytime running lights were mandatory in the U.S., and all vehicles had them, how much extra gasoline would that use each year?

 

[TacomaDCLB]

Why do you guys like DRLs so much? I disabled them frm my 4Runner, and am ecstatic that my Tacoma dosent have them...

 

[swampler]

Why do you guys like DRLs so much? I disabled them frm my 4Runner, and am ecstatic that my Tacoma dosent have them...

I haven't figured it out either. That's one reason I wouldn't buy a Chevy...of course, now that Honda has a truck I have another reason not to buy one!

 

[laserfan]

Spark? did I miss something here? not sure anyone mentioned spark or what you mean by that. At anyrate, don't shoot the messenger, I'm just relaying info when I asked the quesiton to a senior Honda engineer.

Sorry, I didn't intend to connect you to the Honda response in any way vrtrkr.

I think all this talk, including the article referenced, is just *nonsense* UNLESS the alternator is clutched in some way. The electrical devices in the car AFAIK have nothing whatsover to do in re drawing more-or-less gasoline from the tank! The electrical devices draw power from the BATTERY, which in turn is kept energized by the alternator. Now again, unless the alternator is clutched, it is "in the circuit" all the time, belted to the engine, and drawing upon engine power and, yes, the gasoline associated therewith, but the alternator is just another mechanical device, it doesn't use more-or-less of the engine's power depending on battery usage, it's a constant.

The a/c compressor is switched in-and-out as an engine drag by its clutch. So when a/c is on, the compressor presents more drag on the engine and consequently affects MPG. The alternator, UNLESS IT TOO HAS A CLUTCH OF SOME SORT, is a constant drag on the engine, which varies not one whit whether lights are on or not.

Someone correct me, but only if I'm wrong!

 

[laserfan]

P.S. I am relieved, having looked at that ridiculous "Howstuffworks" article, that the government study linked in it says nothing, in "How to drive for more fuel efficiency", about turning lights or other such devices Off.

That's cuz it just doesn't matter, folks.

 

[The Great Tristano]

The electrical devices in the car AFAIK have nothing whatsover to do in re drawing more-or-less gasoline from the tank!

I think I'll retract my statement about conservation of energy. Since automobile engines (even Hondas) are hopelessly inefficient, at about 15% or less, it's very likely that the power consumed by DRL would otherwise just be wasted as heat anyway. So for now DRL probably won't hurt. If we want to save energy we should concentrate on converting all that wasted heat back into something useful.

I still don't like uncontrollable DRL, but thinking about it I can't help but laugh. We're looking at 15% efficiency and complaining about two unnecessary light bulbs?

 

[delphi7x10]

MountainBiker,

Its an interesting article, but full of assumptions. First off what percent of the total miles are over the road haulers, driving 14 hours per day at highway speed, my guess would be about 40% of the miles.
Second if all vehicles were traded in for new ones with DRL the gas saved getting rid of all the old clunkers would put the country ahead, not behind.
Third, he drops the watts from 55 to only 50, where as it should be more like 25 or lower.
And last if it were law tomorrow, then these numbers will all change again, as cars will move to LEDS, with in the next few years, as will most lighting.

Check this out: If daytime running lights were mandatory in the U.S., and all vehicles had them, how much extra gasoline would that use each year?

 

[Featser]

I don't doubt vertrkr's inside info, but the math doesn't seem to support the notion that drawing ~100 watts is dectectable in something as crude as a miliage test.

Also - I must be missing something - can't you just turn the lights on ?

I certainly feel people should have their lights on more than they do, anytime visibility is compromised. But, I wouldn't want to not be able to control them. In city driving, if I'm waiting in back of a sedan at night, I often turn the lights off so as not to blind them. Just because the truck is big doesn't mean it has to be a brute.

 

[vertrkr]

Sorry, I didn't intend to connect you to the Honda response in any way vrtrkr...
Someone correct me, but only if I'm wrong!

No prob, just didn't want anyone thinking I'm making this stuff up.

Now some real world experience the lights put an extra load on the engine. I had totally forgotten about this until now but on my old pickup at one point my engine belt was a little loose. During the day it drove just fine but at night when I turned on my head lights it started screeching as it was slipping on the pulleys and my lights were not as bright as normal. Tightening the belt to spec fixed everything of course but that experience sure tells me something. Take for what ever it's worth.

 

[laserfan]

Sorry you guys, you're still not getting it. The lights have nothing whatever to do with 'energy savings' one way or the other. They are powered off the battery, which is kept "topped-off" by the alternator, and the alternator unless it is clutched is a constant drag on the engine--if you turn on every electrical accessory in the Ridge all it does is drain-down the battery and require more of what the alternator does for it, namely to charge it back up again. If you don't use any electrical, and the battery is at full capacity, then the output of the alternator is dissipated as heat, in the regulation electronics. But there is no savings ANYWHERE in a system like this.

Maybe I'm digging a hole for myself, and Honda has implemented a clutched alternator similar to an a/c compressor, and when the battery is OK the alternator is disconnected from the engine, thereby reducing load and saving gas. This would be great if it does.

But any talk of turning-off car lights and thereby saving energy and the environment is nutso! That Howitworks article was likely written by a tree-hugger that never took even a basic science class!

Edit: I wrote the above while vrtrkr your post appeared. But your experience reinforces my point. If the belt is loose, the alternator doesn't turn, and the battery becomes depleted. But the alternator is SUPPOSED TO be turning 100% of the time, always loading-down the engine, always providing power to the battery, whether the battery needs it or not, whether lights are used or not. If the battery doesn't NEED the juice, the alternator's output is dissipated in the charging electronics, but it is not "saved" nor is the load on the engine reduced in any way.

 

[Mr Manxter]

...but the alternator is just another mechanical device, it doesn't use more-or-less of the engine's power depending on battery usage, it's a constant.....

I beg to differ. The amount of energy required to turn the alternator increases with the amount of draw on the alternator. You might have jumped a dead car at some point in time and if so would have noticed that when you connect the jumper cables, the running vehicles engine has a slight drop in rpm and you can hear the draw on the alternator. The larger the electrical draw the more the engine has to work to spin the alternator and consequently an increase in fuel consumption.