4 ms·

>No, that's not a log of the temperature reading. They logged the temperature SETPOINT. An important distinction. It's a thermostat controlled temperature, tho

by cube13 14y ago

>No, that's not a log of the temperature reading. They logged the temperature SETPOINT. An important distinction. It's a thermostat controlled temperature, though. There's no reason to turn it down if it's set to a comfortable temperature, because it will automatically shut down when the proper cabin temp is reached.

NSAID 14y ago
Eh. My car is thermostat controlled, and I often adjust the temperature because the vents are close enough to me that it can become uncomfortable. The size of a car makes it a little different than setting a thermostat in your house.
ajross 14y ago
The difference between theory and practice is ... Nah, forget it, theory is always wrong. Anyone who drives in the cold knows this is wrong. You turn the set point to 90 at the start of the trip, because the built-in logic is going to drive the fans harder when the delta between ambient and set point is higher, and the car will warm up faster. Yes, in theory the software should recognize that. But, in practice.... Nah, forget it. Theory is always wrong.
- cube13 14y ago
  90 is not a "comfortable" setting, though. I agree completely that's what you do in cold weather. I do that every morning with my car. But after 3+ hours in the car, it's pretty unlikely that you'd lower the temperature at that point. EDIT: Downvotes? Really? If the car's climate control is controlled entirely by a thermostat, then setting the temperature up to 90 will warm it faster when it's cold, but once it's warmed up the cabin, you set the temperature to something comfortable(say, 70). You don't turn it off, because the climate control system is supposed to be doing that automatically.
  - deveac 14y ago
    > If the car's climate control is controlled entirely by a thermostat, then setting the temperature up to 90 will warm it faster when it's cold, but once it's warmed up the cabin, you set the temperature to something comfortable(say, 70). You don't turn it off, because the climate control system is supposed to be doing that automatically. Hi, I live in Michigan. You do turn it off. Your theory sounds like it could be good on paper, but in reality, humans behave a little differently. Our winters are brutal. At some points in the winter time, it's a horrifying proposition climbing into the icebox that is a car's cabin. Reflexively, many people just crank the heat up as high as it will go and blast the cabin with warm air as soon as it's available. As much as you can, as quickly as possible. What tends to happen then is that at some point, you realize that you're hot. You've been blasting the heat, you weren't paying attention (listening to news/music, concentrating on the road, on your phone, etc)and when it suddenly occurs you you that you don't need the heat to be blasting anymore, it's because you are uncomfortable. You're still in full winter gear in your car, you jacket is smothering you, and the cabin is now hot with you in your coat. People aren't always thinking "Ah, let me just lower the heat to a more comfortable level," they're thinking "OMG turn this thing OFF. Could the climate control handle this in theory? Sure. If human psychology and behavior weren't continually getting in the way. No telling what any given person would do when you don't have the data, but I can tell you what people do do in reality. They crank it then turn it off. Also, I'll never purchase another car without heated seats in Michigan again as long as I live here. What was I (not) thinking?
    - wjy 14y ago
      Being a controls engineer, this behavior always drives me crazy. I love to observe the temperature controller do its job. But it does depend on the car. A good controller will blast the heat at max until the temperature gets close to the setpoint, then back it down. Turning it up to 90 does exactly nothing extra for you, but does end up overheating you. However, not all cars have good temperature controllers. My wife owned a Honda Accord a while back, that was simply awesome at this job. We never, ever changed the setpoint in that car because it just worked great. The Subaru Forester we have now is much, much worse, and we do end up fiddling with the setpoint because the controller's not doing its job well.
- thetinguy 14y ago
  Really? No. The fans spin up as quickly as they can in a cold car. If you turn the fan up and the temperature up all the way when you start the car, you are just blowing cold air on yourself. The fans spin up when they can actually deliver warm air. Keep in mind of course this is in a climate controlled car, like the Tesla S.
  - ajross 14y ago
    Indeed! And here's you've given a perfectly good theoretical answer for why cars do the verifiably incorrect thing. The problem here is your handwavy use of "as they can" to invoke some kind of hidden expertise that doesn't actually exist in the real world. The car has some vague idea of what the current fan outlet temperature is, based mostly likely on one or two thermocouples in the chain, or maybe just on the engine coolant temperature. And some egghead firmware engineer somewhere built a very solid, justifiable model of "rider comfort" and optimized the control response to that, thus giving the theoretically optimal experience for... Nah, forget it. Theory is always wrong. I spend an hour in my car every day. Don't you[1] dare tell me how best to warm it up. Just don't. [1] To head off the wounded screaming: no, I'm not talking about you personally here. Just the idea of "firmware knows best".
    - wjy 14y ago
      Edit: grammar Some cars are really good at this. Some are not. It depends on so many factors, including the egghead quality. I'm one of those firmware eggheads, btw. As another example, when I fuel my car from emtpy to full, as soon as I turn the key, the fuel gauge ramps rapidly up to Full. In my wife's car, it finds its way to Full after a minute or so. I don't know, but I'm pretty sure the difference is the filtering algorithm employed. One egghead knew about Kalman filters or similar, and the other didn't. It's the same with all the other software features in the car. Some had good eggheads on the time, and some didn't. I think it's impossible to buy a car that does every single thing "right", by any single person's definition.
      - cuu508 14y ago

by cube13 14y ago

NSAID 14y ago

Eh. My car is thermostat controlled, and I often adjust the temperature because the vents are close enough to me that it can become uncomfortable. The size of a car makes it a little different than setting a thermostat in your house.

ajross 14y ago

The difference between theory and practice is ... Nah, forget it, theory is always wrong. Anyone who drives in the cold knows this is wrong. You turn the set point to 90 at the start of the trip, because the built-in logic is going to drive the fans harder when the delta between ambient and set point is higher, and the car will warm up faster. Yes, in theory the software should recognize that. But, in practice.... Nah, forget it. Theory is always wrong.

cube13 14y ago
90 is not a "comfortable" setting, though. I agree completely that's what you do in cold weather. I do that every morning with my car. But after 3+ hours in the car, it's pretty unlikely that you'd lower the temperature at that point. EDIT: Downvotes? Really? If the car's climate control is controlled entirely by a thermostat, then setting the temperature up to 90 will warm it faster when it's cold, but once it's warmed up the cabin, you set the temperature to something comfortable(say, 70). You don't turn it off, because the climate control system is supposed to be doing that automatically.
- deveac 14y ago
  > If the car's climate control is controlled entirely by a thermostat, then setting the temperature up to 90 will warm it faster when it's cold, but once it's warmed up the cabin, you set the temperature to something comfortable(say, 70). You don't turn it off, because the climate control system is supposed to be doing that automatically. Hi, I live in Michigan. You do turn it off. Your theory sounds like it could be good on paper, but in reality, humans behave a little differently. Our winters are brutal. At some points in the winter time, it's a horrifying proposition climbing into the icebox that is a car's cabin. Reflexively, many people just crank the heat up as high as it will go and blast the cabin with warm air as soon as it's available. As much as you can, as quickly as possible. What tends to happen then is that at some point, you realize that you're hot. You've been blasting the heat, you weren't paying attention (listening to news/music, concentrating on the road, on your phone, etc)and when it suddenly occurs you you that you don't need the heat to be blasting anymore, it's because you are uncomfortable. You're still in full winter gear in your car, you jacket is smothering you, and the cabin is now hot with you in your coat. People aren't always thinking "Ah, let me just lower the heat to a more comfortable level," they're thinking "OMG turn this thing OFF. Could the climate control handle this in theory? Sure. If human psychology and behavior weren't continually getting in the way. No telling what any given person would do when you don't have the data, but I can tell you what people do do in reality. They crank it then turn it off. Also, I'll never purchase another car without heated seats in Michigan again as long as I live here. What was I (not) thinking?
  - wjy 14y ago
    Being a controls engineer, this behavior always drives me crazy. I love to observe the temperature controller do its job. But it does depend on the car. A good controller will blast the heat at max until the temperature gets close to the setpoint, then back it down. Turning it up to 90 does exactly nothing extra for you, but does end up overheating you. However, not all cars have good temperature controllers. My wife owned a Honda Accord a while back, that was simply awesome at this job. We never, ever changed the setpoint in that car because it just worked great. The Subaru Forester we have now is much, much worse, and we do end up fiddling with the setpoint because the controller's not doing its job well.
thetinguy 14y ago
Really? No. The fans spin up as quickly as they can in a cold car. If you turn the fan up and the temperature up all the way when you start the car, you are just blowing cold air on yourself. The fans spin up when they can actually deliver warm air. Keep in mind of course this is in a climate controlled car, like the Tesla S.
- ajross 14y ago
  Indeed! And here's you've given a perfectly good theoretical answer for why cars do the verifiably incorrect thing. The problem here is your handwavy use of "as they can" to invoke some kind of hidden expertise that doesn't actually exist in the real world. The car has some vague idea of what the current fan outlet temperature is, based mostly likely on one or two thermocouples in the chain, or maybe just on the engine coolant temperature. And some egghead firmware engineer somewhere built a very solid, justifiable model of "rider comfort" and optimized the control response to that, thus giving the theoretically optimal experience for... Nah, forget it. Theory is always wrong. I spend an hour in my car every day. Don't you[1] dare tell me how best to warm it up. Just don't. [1] To head off the wounded screaming: no, I'm not talking about you personally here. Just the idea of "firmware knows best".
  - wjy 14y ago
    Edit: grammar Some cars are really good at this. Some are not. It depends on so many factors, including the egghead quality. I'm one of those firmware eggheads, btw. As another example, when I fuel my car from emtpy to full, as soon as I turn the key, the fuel gauge ramps rapidly up to Full. In my wife's car, it finds its way to Full after a minute or so. I don't know, but I'm pretty sure the difference is the filtering algorithm employed. One egghead knew about Kalman filters or similar, and the other didn't. It's the same with all the other software features in the car. Some had good eggheads on the time, and some didn't. I think it's impossible to buy a car that does every single thing "right", by any single person's definition.
    - cuu508 14y ago