Keeping appliances unplugged

[iwire]

but yes one of the reasons they run cooler, is unlike gas aspirated combustion engines, they have a wide open intake, no throttle valve that closes off in coming air, the engine speed and power is controlled at the injectors by limiting the amount of fuel the engine receives, (you don't want to hit one with either while running) this constant flow of air allows the engine to run much cooler, and when you add super chargers and or turbo's it can run even cooler.

I am sorry but I am calling you on that it takes a certain air / fuel ratio to burn the the fuel efficiently and a air valve on the intake does not change that ratio. Turbos or supper chargers do almost nothing at idle and when they do start pushing air in the temps go up. (More air pressure / more fuel burned etc.)

 

[Besoeker]

http://www.consumerenergycenter.org/myths/idling.html

Myth #1: The engine should be warmed up before driving. Reality: Idling is not an effective way to warm up your vehicle, even in cold weather. The best way to do this is to drive the vehicle.

 

[jim dungar]

http://www.consumerenergycenter.org/myths/idling.html

I have lived in Wisconsin for +35yrs, current temperature is 19?F, which is a little warmer than normal.
I have never idled the engine simply to warm it up. I do let my wife's car idle to warm up the passenger compartment when the temp is below 0?F.

 

[Besoeker]

I have lived in Wisconsin for +35yrs, current temperature is 19?F, which is a little warmer than normal.
I have never idled the engine simply to warm it up. I do let my wife's car idle to warm up the passenger compartment when the temp is below 0?F.

Yes, been to Wisconsin (cheese state?) a couple of times. Once was in the spring, maybe April or May. I drove from Milwaukee airport to Madison. Still snow at the side of the road.

I confess to letting my car idle for a little bit if I have to clear snow or frost off the windscreen. It also lets the seats warm up. Mrs B likes that.
But I would never leave it running and unattended.

 

[hurk27]

I am sorry but I am calling you on that it takes a certain air / fuel ratio to burn the the fuel efficiently and a air valve on the intake does not change that ratio. Turbos or supper chargers do almost nothing at idle and when they do start pushing air in the temps go up. (More air pressure / more fuel burned etc.)

First, A Diesel engine does not compress an air/fuel mixture as in gas engines, it's only compressing air, the fuel is added after the compression stroke via direct cylinder injection, there is no throttle butterfly as air intake is wide open.

See this page on runaway diesels: http://en.wikipedia.org/wiki/Diesel_engine_runaway

While diesel fuel has more heat content per gallon of fuel (about 10%) the volume of air running through the engine helps to remove much more heat content then in a same sized gas engine, ever note the very large size intake and exhaust pipes to allow more air flow when compared to a same size gas engine?

While I agree at lower RPM's a supercharger or turbo charger is flowing less air, the engine is also producing less heat at this time, it is at driving speeds where this effect is most noticed, and driving older diesel trucks in the winter, it can be hard to keep them warm, and again one of the reasons you see drivers putting cardboard in front of their radiators to allow the engine to build up heat, diesels don't run very well cold, and are very inefficient when doing so.

Next time you talk to a truck driver, ask him how hard it is to keep a diesel warm in the winter even running down the road.

 

[kwired]

First, A Diesel engine does not compress an air/fuel mixture as in gas engines, it's only compressing air, the fuel is added after the compression stroke via direct cylinder injection, there is no throttle butterfly as air intake is wide open.

See this page on runaway diesels: http://en.wikipedia.org/wiki/Diesel_engine_runaway

While diesel fuel has more heat content per gallon of fuel (about 10%) the volume of air running through the engine helps to remove much more heat content then in a same sized gas engine, ever note the very large size intake and exhaust pipes to allow more air flow when compared to a same size gas engine?

While I agree at lower RPM's a supercharger or turbo charger is flowing less air, the engine is also producing less heat at this time, it is at driving speeds where this effect is most noticed, and driving older diesel trucks in the winter, it can be hard to keep them warm, and again one of the reasons you see drivers putting cardboard in front of their radiators to allow the engine to build up heat, diesels don't run very well cold, and are very inefficient when doing so.

Next time you talk to a truck driver, ask him how hard it is to keep a diesel warm in the winter even running down the road.

If it is loaded it helps. My diesel truck does not warm up much until you start driving - at highway speeds where there is more significant load, then it is countered by air speed cooling it, but still warms up better. If it is cold enough outside but had been warmed up then you let it idle, it will start getting colder again.

 

[ActionDave]

I confess to letting my car idle for a little bit if I have to clear snow or frost off the windscreen. It also lets the seats warm up. Mrs B likes that..

Windscreen?

 

[hurk27]

If it is loaded it helps. My diesel truck does not warm up much until you start driving - at highway speeds where there is more significant load, then it is countered by air speed cooling it, but still warms up better. If it is cold enough outside but had been warmed up then you let it idle, it will start getting colder again.

Not to much experienced with many of the newer engines in pickups, only worked on a few older ones, like the GM 350 conversion block in some chevy's, most of my experience came from working on semi's at one of my dad's trucking companies, he had back when I was much younger, he got me some books on them and I able to learn about the basic operations of a diesel and the differences to gas engines, I would believe that non-professional vehicles would have more temp control then the big trucks had back then, like a better system of controlling coolant water, and radiator fan control, that would allow them to run warmer in the winter time, even the big trucks have come along way as I see many with controlled louvers in front of the radiators, but I still see many with made covers that snap across the grill, even on the new school busses around here, so it still seems to be a problem to keep them warm, I know my backhoe 675 Ford, diesel would warm up to half mark in the summer, in the winter would barely get up to the quarter mark on the gage in the winter.

 

[George Stolz]

I just feel guilty moving my truck listening to the lifters clattering on a 0 degree morning and fogging up the windshield after a moment behind the wheel. I won't drive it unless it's been running for five minutes.

How the heck did this conversation get so far off topic anyway? :huh:

 

[hurk27]

I just feel guilty moving my truck listening to the lifters clattering on a 0 degree morning and fogging up the windshield after a moment behind the wheel. I won't drive it unless it's been running for five minutes.

How the heck did this conversation get so far off topic anyway? :huh:

I have no idea, I think the first conversation was already beat to death?

 

[jim dungar]

I have no idea, I think the first conversation was already beat to death?

There was a different conversation?hmy:

 

[iwire]

First, A Diesel engine does not compress an air/fuel mixture as in gas engines, it's only compressing air, the fuel is added after the compression stroke via direct cylinder injection, there is no throttle butterfly as air intake is wide open.

See this page on runaway diesels: http://en.wikipedia.org/wiki/Diesel_engine_runaway

While diesel fuel has more heat content per gallon of fuel (about 10%) the volume of air running through the engine helps to remove much more heat content then in a same sized gas engine, ever note the very large size intake and exhaust pipes to allow more air flow when compared to a same size gas engine?

While I agree at lower RPM's a supercharger or turbo charger is flowing less air, the engine is also producing less heat at this time, it is at driving speeds where this effect is most noticed, and driving older diesel trucks in the winter, it can be hard to keep them warm, and again one of the reasons you see drivers putting cardboard in front of their radiators to allow the engine to build up heat, diesels don't run very well cold, and are very inefficient when doing so.


time you talk to a truck driver, ask him how hard it is to keep a diesel warm in the winter even running down the road.

Hurk I know about engines, I was a gear head for years. And yes diesels are though to get warm but that does not have to do with the lack of an air valve on the intake.

 

[iwire]

http://www.consumerenergycenter.org/myths/idling.html

They have an agenda.

They also say this....

HERE'S THE RULE OF THUMB: If you're in a drive-through restaurant/business line or waiting for someone and you'll be parked and sitting for 10 seconds or longer... turn off your car's engine.

Would you do that?

There is no question getting the oil warmed up a bit before using the engine hard is better for it.


Not to mention getting the ice or frost off the windows is also a plus.

 

[Besoeker]

Windscreen?

Windshield.

 

[Besoeker]

They have an agenda.

If so, I don't suppose it's about increasing engine wear.

They also say this....



Would you do that?

To save fuel. It's what hybrids routinely do for that reason.

There is no question getting the oil warmed up a bit before using the engine hard is better for it.

Hard, I agree and I would never do that.

 

[hurk27]

Hurk I know about engines, I was a gear head for years. And yes diesels are though to get warm but that does not have to do with the lack of an air valve on the intake.

Ok I think I know where you are coming from, and yes, the higher efficiency does play a big part of why a diesel runs cooler, but I was also pointing out that a diesel also has much more cool air coming into the engine which is unrestricted by the throttle plate that also helps keep a diesel cooler, at least that was what I was taught by my dads machanic, also the fact is diesels have a much higher compression ratio which along with the longer stroke allows the air more time to expand and cool, there are many things that play into this, so you are correct that its just not the intake air, I guess I'm still learning

Here is a little excerpt from
http://en.wikipedia.org/wiki/Internal_combustion_engine_cooling
If others want to read about it.

Heat engines generate mechanical power by extracting energy from heat flows, much as a water wheel extracts mechanical power from a flow of mass falling through a distance. Engines are inefficient, so more heat energy enters the engine than comes out as mechanical power; the difference is waste heat which must be removed. Internal combustion engines remove waste heat through cool intake air, hot exhaust gases, and explicit engine cooling

 

[ActionDave]

Windshield.

Ahhh, yes.

 

[iwire]

but I was also pointing out that a diesel also has much more cool air coming into the engine which is unrestricted by the throttle plate that also helps keep a diesel cooler

And I am pointing out that the throttle plate, or lack there of has nothing to do with keeping a diesel cooler.

The air flow on a diesel is not 'unrestricted' it still only moves as fast as the positive displacement pump (the engine) moves it. In the case of the diesel the fuel flow controls the speed of the 'pump' and therefore the airflow.


You pointed out this

Internal combustion engines remove waste heat through cool intake air,

I have not, and don't dispute that, but it applies to both diesel and gas engines.

 

[iwire]

If so, I don't suppose it's about increasing engine wear.

No, the agenda is not increasing engine wear, the agenda is saving fuel and they will ignore increased engine wear to achieve that goal.

To save fuel. It's what hybrids routinely do for that reason.

Yes, and he jury is out on how that will work out for engine wear.

Every start with 0 oil pressure adds to the wear on the engine.

Hard, I agree and I would never do that.

My wife would, and does, I pointed that out above.

Now do I always pre-start and let it warm up? No, if I have to go quickly I will start it and drive gently, it will warm up much faster than sitting in my driveway.

But IMPO given the choice in cold weather I would rather warm up first, both for the engine and my own comfort.

You had mentioned that at a low crank RPM the oil pump speed is low. I agree (of course), but I have never had a vehicle that did not show higher oil pressure when cold due to thicker oil. To me that is an indication the pump is doing all it can to move the thick oil through the engine passages. And more RPM will only send more oil through the pressure bypass back to the sump.

But ....... it's car talk, and you are a gear head too, which means we will never change each others views.

Now, it is 23F and I have to run out and start my truck.

 

[GeorgeB]

I always laugh when I hear the "green" people say you should turn off your cables boxes. Cable and sat boxes take so long to reboot that it is completely unrealistic to remove power after each use. The ones I have dealt with can take anywhere from 5 minutes to 30 minutes each time.

I had one which my "Kill A Watt" said drew 60W off ... but its replacement is in the 2W range (wall-wart powered now).

The box manufacturers have improved things LOTS.