Well duh, taillights are not on. only front lights.
I also take issue with the numbers. They used simple math that it takes X power to make a given amount of energy. It is not linear.
You need X power to turn the alternator no matter how much power is actually generated. If the car was usung a lot of electrical drvices the add on may be accurate. It it is sing very little it may not take any additional power for the energy consumed. Remember, the alternator is turning based on the rpm of the engine.
For the past few decades I've run manufacturing plants. It takes a certain amount of fuel to bring the boilers up to pressure. When we start one of the small machines we see zero increase in consumption because what we don't use is otherwise lost at idle. That 7 teaspoons a day may really be 3.
You're forgetting a few things. The energy spent converting 'ethanol' for those few teaspoons. You're also neglecting the fact that although the lights are on half power for daytime running, (I'm going to use the lifted s10 for the example, as I've already examined it) it's using a 12volt relay to provide power for daytime running lights. So, I'm wasting current with an additional relay, additional wiring, likely a resistor (or another circuit doing the same thing) to drop the voltage by half; wasting it as heat most likely.
More wire, More plastic in the relay box (for the additional relay that runs DLR) additional circuitry, more power consumption, more electronics.. for little/if any real benefit possibly! for some! other cars coming in my direction. And, that's just what the vehicle itself is wasting. Not even including the additional material used to create the additional space in the box to hold the relay, or the materials used to construct the relay. Make a few million of those and the by product waste starts to add up.
For cars using electronics and no actual relay, it's more wasteful in terms of by products and energy used to create the additional circuitry and components.
It's also another point of potential failure within the cars electrical system. More devices, more complicated circuitry, the higher the chances of failure.
I personally don't worry about it, I tend to disable them. I don't see any real benefit to shortening the life of my headlights. I recently acquired a car that also has daytime running lights, and since the headlight control switch failed (I'm not about to spend 80 dollars for it) I resorted to mapping it out with a meter and toggle switched everything, except the daytime run lights. It also uses a
12volt powered relay to run them. Waste of resources, waste of time. Very little (if any) gain by having them.
Oh.. yes, references, proof, I'm sure you'll be requesting them... I'm going to borrow FTR's post with the useful url
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No real significant advantage to having DLR in the USA; aside from an increased risk of a crash involving a cyclist and/or pedestrian.
I don't think facts factor much in some cases here. Some of the posters remind me of virus_guy actually. Take for example the ill conceived notion that John McCain was a hero. I'm sure his surviving shipmates would disagree with that statement.
Except that what Doug wrote isn't really backed up by facts. When you consider the additional resources spent providing this 'feature', you really are losing, not gaining. The s10 example I provided uses a
12volt relay to run the DLR circuit. 12volts to keep the relay closed so it can provide 6volts or so to the headlights. Additional wiring, additional circuitry, additional plastic molding efforts to support the relay that has no other purpose on the vehicle. Not to mention the energy used to create the relay itself, the plastic and the additinal support circuitry required for the DLR to work.
Where exactly is the benefit?
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Interesting analysis, too. They seem to have reached the conclusion that these DLR lighting systems provide no real safety advantage for the driver or the oncoming cars, but, do infact, have a real negative effect for cyclists and pedestrians.
When you consider the energy and resources wasted to equip cars/trucks with the feature in a mass production scale, you aren't coming out ahead. You're wasting resources, instead.
The more power demands on the alternator, the more resistance to being turned it places on the engine, which forces the engine to work that much harder. IE: more fuel is consumed to keep the alternator turning at the rpms desired. You aren't just providing additional power to the headlights themselves for DLR, you're also providing additional power to the circuitry (possibly including a 12volt relay) that allows DLR to function. So you can't really say that because your headlights in DLR mode are only using 6volts that's all the additional power that's required. It's not. You still have a relay/possible other electronics to feed too. You don't get anything for free.
They waste energy with the bulbs themselves AND the support circuitry required to run them at half voltage. Ironically, with the s10, it's using a 12volt relay for the DLR circuit, and, I strongly suspect a resistor to drop the voltage by half to feed thru the relay to the lights. So, the truck has additional plastic molding to hold the additional relay, the materials used to construct the relay that serves no other function, the wiring, Additional programming of the trucks computer, a photo voltaic cell (I'm assuming thats whats sitting in the middle of the dash behind the windshield to determine whether or not it should shut off DLR and run full power or not.
And, it's mass produced, so a considerable amount of energy and resources were wasted doing it. I suppose it's 'nice' that the truck turns the lights on for me if it thinks it's dark outside (ie: I entered a tunnel on a bright sunny day), but, I can turn the lights on myself. I don't need the truck to do it for me. The truck won't switch over from DLR to headlight full if it detects rain, either. It requires the outside light level to change. As, the truck in my case, has no idea something is hitting the windshield; it has no sensors to tell it anything about the windshield. It requires the light entering that cell/sensor to drop to a certain level before it'll go from DLR to full on headlights.
That's also causing an additional load on my alternator, which in turn causes the engine to have to work a little harder to keep the rpms where they should be. As, the more power demands made on the alternator, the more resistance to being turned by the engine.
Also, when one considers how much energy is consumed to make ethanol enriched gasoline (which is nearly all we have access to here in tn), it doesn't add up to a savings. It's a net loss.
Taillight are not deemed to have a benefit as DRL are.
While the power generated can affect the energy needed, even if no power is generated the hardware still is tuening. You have frictional load from bearings and anything else making contact.
That is true once it exceeds the basic load of turning the equipment. If no power is used the alternator does not stop, it is still turning making minimal power, needed or not. Unless you have a clutch to disengage or remove the belt, it is using power from the engine to spin. If it spins it makes electricity and it may be enough to power the DRL with no additional load.
I've not seen any tests done to actually measure the difference, only theoretical derivatives.
Even in low visibility conditions? Come on, you can do better than that. If the performance hit is negligible - why not?
Plus, DRL benefits are disputed.
Yes, minus the magnetic effect which is added when the electrical load increases. If the 'energy fairy' concept works for you that's fine, but don't expect me to buy it.
Bullshit! The effect of 'generation' is actually only 'conversion' and the more you demand, the harder it is to turn the rotor and the more chemical energy is converted to electrical energy. It matters not whether it is friction or friction plus magnetism that the engine is overcoming.
Well maybe you should then. Hook up a generator to a lamp or other device through a switch. Hand crank the generator with the switch open, then have somebody throw the switch on.
Yes. I think it is the schoolboy level attempts at denigration that remind me of him. I usually gave him and Ray some leeway though because of the humor in their retorts.
I think it boils down to the idea that it is okay to give the fuel companies another 2 million gallons of gasoline sales per year as long as each individual only gives up a teaspoon or so under the misconception that it actually saves lives or prevents accidents.
I don't care one way or the other really, but I am *not* the one who needs to get acquainted with the facts because I am 'puzzled'. I am
*not* 'in over my head' or 'the village idiot' just because I have an opinion about Ohm's Law which differs from the pack of wannabe engineers here. IMO, there are some otherwise intelligent people here who need to 'get off of their high horses' and treat others with some respect instead of denigrating everyone to make themselves feel worthy.
If there are low visibility conditions your headlights should be on. Wipers on, headlights on. Half hour beforse sunset, hald hour after sunrise. Fog, mist whatever.
Apples/oranges. The alternator on a car is spinning pretty fast when the engine rpm is 1.000 and more. Wasting power in many cases.
That's true, and it was somebody else (not you) who said that DRLs were proven to increase visiblity 'even in low visibility conditions' so I'm willing to overlook that whole idea. The answer to my 'why not' question is then that there was cost but no proven benefit.
That is exectly what they say about DRLs in the daytime without the 'low visibility' conditional. There is no proven benefit to them, and there is cost albeit not very much cost (only about 2 million gallons of gasoline per year in the US according to math which you apparently disagree with) to having them mandated.
The Department of Transportation's National Highway Traffic Safety Administration's study laid out the methodology and the reasons for the differences between their methodology and the European and Canadian studies. Their conclusion was that there was no statistically significant reduction in crashes of passenger vehicles to warrant having them mandated. They mention cost in fuel only peripherally with this statement:
"In addition to glare, there are concerns that DRLs might make motorcycles, pedestrians, and pedalcyclists less conspicuous and that DRLs would increase fuel consumption and have an adverse impact on the environment"
Rotation speed is almost irrelevant, and I disagree with the wasting power idea unless you are not talking about electrical power. Sure, the spinning is useless and tha added weight to the vehicle (which is almost as negligible as the spinning) adds to fuel consumption.
The alternator rotor is practically just a rotating mass on ball bearings until you draw current from the stator windings, it is then that the (opposing) stator fields make the rotor physically harder for the internal combustion engine to rotate - which causes it to consume fuel at a slightly faster rate.
Oh, and no fruit was harmed in the making of this post.
You realize, the headlights themselves (for DRL) aren't the only devices now using additional power when fired up, right? A 12volt relay (multiple in some cases/configurations) is also in play. Along with additional circuitry to tell the relay to come on/go off, etc. None of this is free.
We'd most likely have to use an electric clutch like the one on AC compressors. So, we'll need additional circuitry to monitor the voltage on the bus to determine if we need to engage it or not. And, this allows for more points of failure with the clutch assembly and or required support circuitry. We're making this more complicated to do what exactly? What gain would we get by doing this?
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