Is this real?

[Mike Schneider]

The local newspaper published this in the "Letters to the Editor" section. "Please also consider turning off daytime running lights (DRLs) on automobiles. Estimates of increased fuel usage because of DRLs range from 0.5 to 3 percent...." I know this isn't much of an increase, but could this be true? Let's leave the safety aspect for another thread. Thanks. - Mike

 

[jesse]

Theoretically it probably does increase load on the motor. Enough to be of statistical significance? I doubt it. There are a lot better ways to increase efficiency then worry about the barely measurable...

Most vehicles have a separate set of daytime running lights that would draw very little. Generally these energy saving concepts are written by tree hungers that do a lot of assuming and not a whole lot of checking.

We do know that daytime running lights save lives. If there is a person out there who thinks a barely measurable increase in fuel is worth decreasing safety..They need to be smacked upside the head.

Expect a better answer from Lance

 

[poadeleted20]

I'd put that letter in a class with the phone call received by the Glens Falls NY airport manager during the AYA convention there two weeks ago from a woman who lives near the airport asking that we stop flying so much because she can't sunbathe nude with all of us flying overhead.

BTW, the manager refused to tell us where she lived.

 

[RotaryWingBob]

I'd put that letter in a class with the phone call received by the Glens Falls NY airport manager during the AYA convention there two weeks ago from a woman who lives near the airport asking that we stop flying so much because she can't sunbathe nude with all of us flying overhead.

BTW, the manager refused to tell us where she lived.

Why do you think we helicopter drivers fly so low, Ron?

 

[Cap'n Jack]

Om a bicycle, I can feel the "drag" from a generator feeding a light, and the loss of drag when a connection breaks. I can also feel the differance when I put 15 lb in my tires to bring them back to rated pressure (90 PSI). It is only a couple of pounds of force in either case.

A car isn't a bicycle- the tires have more resistance, the AC is running in the summer, radio running (how many watts does that draw when you have decent spreakers?), etc. I don't think the lights add much to the overall power draw.

 

[KennyFlys]

There's so much torque in the diesel engine of my VW TDI, when I turn on the AC there is no noticeable change in the engine, no change in sound, nothing. You have to be right on top of the compressor with the hood up to even hear it kick in. It also has no effect on fuel mileage.

It sounds like a solution if you run a heavy load on an engine.

 

[L10MAN]

Maybe that explains why so many morons out there don't use their turn signals -- they're actually saving the planet by reducing their fuel usage.
Ron

 

[jshawley]

It does indeed add load on an engine; hence you see 1,250MW(E) nuclear power plants. That adds up to a lot of light bulbs. But how much would be saved by turning off DRLs is anybody's guess. I'm too lazy to try to math it out (P=IE X how many cars/trucks/&c X total time, then convert to bbls of oil, yadda, yadda, yadda).

But it would add up, to at least a measurable amount. Someone with a lot of time could likely estimate it, I'm certain.

Oh, and Cap'n Ron--remember to keep flying the plane while performing the "search and rescue" missions . All the local swimming pools in the pattern here seem to be deserted. Dunno why...

 

[gismo]

There's so much torque in the diesel engine of my VW TDI, when I turn on the AC there is no noticeable change in the engine, no change in sound, nothing. You have to be right on top of the compressor with the hood up to even hear it kick in. It also has no effect on fuel mileage.

It sounds like a solution if you run a heavy load on an engine.

The reason you don't feel the A/C kick in is because the engine controls increase the power slightly when the compressor is on. Still the HP required for modern auto A/C is pretty low, perhaps less than one HP. A car running 60 MPH and getting 30 MPG is producing 24-28 HP so the A/C might account for a 4-5% drop in economy.

The DRLs OTOH consume around 50W or about 0.07 HP assuming about 85% efficiency for the alternator. That would affect the fuel economy of that 30 MPH car by a whopping .25%. And that assumes you only drive in the daytime.