Amazing climate control

[jmann]

The climate control system is amazing. It really is the best I have ever used in a car. When I use to drive a 96 saab with auto-air, it was awful. Then I drove a 2003 Grand Am with manual air. To have this 2006 with auto air is great. I forgot how important this feature was to me.

But what's more important is that the quality of the auto-climate system is unparalleled in my experience. Within four minutes my car is cold or warm and comfortable for the rest of my drive, with the same settings, summer or winter. There are so many cars that I have had to fight with the auto climate system to stay comfortable. Toyota has got it down.

[seasalsa]

<div class='quotetop'>QUOTE(jmann @ Jan 28 2007, 04:51 PM) [snapback]382085[/snapback]</div>

The climate control system is amazing. It really is the best I have ever used in a car. When I use to drive a 96 saab with auto-air, it was awful. Then I drove a 2003 Grand Am with manual air. To have this 2006 with auto air is great. I forgot how important this feature was to me.

But what's more important is that the quality of the auto-climate system is unparalleled in my experience. Within four minutes my car is cold or warm and comfortable for the rest of my drive, with the same settings, summer or winter. There are so many cars that I have had to fight with the auto climate system to stay comfortable. Toyota has got it down.
[/b]

I totally agree. It is great if you don't screw it up by trying to modify it to work like your last car. It is a state of the art system designed specifically for the prius.

See http://www.denso.co.jp/AR-e/1998/TW/climate.html

There have been several posts complaining about the lack of heat or cooling. It works great if you just set it and forget it.

Many fail to realize that the traction battery temperature is maintained by the inside temperature of the cabin. The more comfortable you keep the cabin the happier the hybrid car battery will be.

[Tideland Prius]

<div class='quotetop'>QUOTE(seasalsa @ Jan 28 2007, 05:19 PM) [snapback]382094[/snapback]</div>

I totally agree. It is great if you don't screw it up by trying to modify it to work like your last car. It is a state of the art system designed specifically for the prius.

See http://www.denso.co.jp/AR-e/1998/TW/climate.html

There have been several posts complaining about the lack of heat or cooling. It works great if you just set it and forget it.

Many fail to realize that the traction battery temperature is maintained by the inside temperature of the cabin. The more comfortable you keep the cabin the happier the hybrid car battery will be.
[/b]

I thought that site was taken down?


Anyway, in case jmann wants to know, that site basically gives you a description of how the Prius' ACC system works.


- it's a two-tiered system. This means, when asking for heat, it sends fresh air to the upper vents to prevent fogging and recirculated air to the foot vents to get heat faster to the cabin

- it also has a humidity sensor to determine when to cycle on/off the A/C compressor

- it runs off the HV battery so you can get A/C in the summer while the engine is off

[tmorrowus]

I remember reading the new features list and here's why I think the climate control system works so well: It isn't just a simple thermostat that turns the heat on or off depending on a single temperature sensor. Rather it takes lots of inputs: humidity, temperature in cabin, temperature outside, and sunlight level (via the round sensor on the dash). It then has a complicated fuzzy logic computer program that integrates all those inputs together to get the right temperature.

It knows that if the sun is really strong, then the sunlight striking the skin of the humans inside will make them warm even if the cabin temperature is perfect. So I think it lowers the cabin temperature so that the human feels like they are at the set temperature.

Similarly it knows that if the outside temperature is low then it will have to heat the air coming in more than it would if the outside temperature was warm. So it reacts quickly when you take your car out of a heated garage out into winter weather, or vice versa.

In other words the car is not just looking at what the actual cabin temperature is, but rather it looks at what are the factors that will make the occupant feel a particular temperature, so it can react before the cabin temperature changes uncomfortably.

It really works best when you set it and forget it.

[jmann]

By the way, here is that link archived

Side note: has anyone else noticed how much faster archive.org has been recently. I wonder what they did.

[qbee42]

<div class='quotetop'>QUOTE(tmorrowus @ Jan 28 2007, 09:03 PM) [snapback]382110[/snapback]</div>

I remember reading the new features list and here's why I think the climate control system works so well: It isn't just a simple thermostat that turns the heat on or off depending on a single temperature sensor. Rather it takes lots of inputs: humidity, temperature in cabin, temperature outside, and sunlight level (via the round sensor on the dash). It then has a complicated fuzzy logic computer program that integrates all those inputs together to get the right temperature.
[/b]

It needs another sensor for my perimenopausal wife; I haven't seen a system yet that can cope with those hot flashes (picture us driving through the Northern Michigan snow, windows down, me freezing my a$$ off!)

Tom

[seasalsa]

<div class='quotetop'>QUOTE(Tideland Prius @ Jan 28 2007, 05:31 PM) [snapback]382097[/snapback]</div>

I thought that site was taken down?
[/b]

OOPS, Sorry. Here is a Quote from the old site that lists some of the features of the system.

Air-conditioning systems should not rob torque from hybrid powertrains on hot summer days. And they need to be able to heat interiors on cold days with little help from engine heat. For the Toyota Prius hybrid car, we developed an ultra efficient air-conditioning system that consumes minimal power.

Our new sub cool condenser and scroll compressor, equipped with oil separators, allow the air-conditioning system to run on 30% less power than conventional systems. And a two-layer flow heating, ventilating, air conditioning (HVAC) unit saves energy by re-circulating heat already in the cabin.

Air conditioners consume as much as 5% of engine output in passenger cars.
The climate-control system we created for the Toyota Prius consumes 30% less power than conventional systems of comparable performance. That improvement in energy efficiency is the result of advances in individual components and--equally important--improvements in overall system configuration.

Concern for the environment spurred automakers to create more efficient engines. But more-efficient engines mean less heat for warming vehicle interiors. Heating units have had to become even more efficient to compensate for lack of the waste heat that conventional systems use.

We have developed a system for the Prius that gets the same performance as conventional systems despite the lack of engine heat available for the system. Ventilation loss--heat that escapes from the cabin as fresh air comes in--accounts for 60% of the heating load placed on air-conditioning systems. Our two-layer flow air-conditioning system re-circulates warm air in the cabin to raise heating efficiency.

By using a 50/50 ratio of fresh and re-circulated air we were able to reduce the ventilation load 50%. At the same time, we were able to achieve the same cabin temperatures possible with conventional systems. Warm cabin air has a high moisture content. So, simply re-circulating the cabin air would fog up the windows. The new system sends re-circulated air out at foot level. Drier fresh air flows near the windows, which prevents moisture from condensing on the glass.

[Tideland Prius]

<div class='quotetop'>QUOTE(seasalsa @ Jan 28 2007, 07:35 PM) [snapback]382141[/snapback]</div>

OOPS, Sorry. Here is a Quote from the old site that lists some of the features of the system.

Air-conditioning systems should not rob torque from hybrid powertrains on hot summer days. And they need to be able to heat interiors on cold days with little help from engine heat. For the Toyota Prius hybrid car, we developed an ultra efficient air-conditioning system that consumes minimal power.

Our new sub cool condenser and scroll compressor, equipped with oil separators, allow the air-conditioning system to run on 30% less power than conventional systems. And a two-layer flow heating, ventilating, air conditioning (HVAC) unit saves energy by re-circulating heat already in the cabin.

Air conditioners consume as much as 5% of engine output in passenger cars.
The climate-control system we created for the Toyota Prius consumes 30% less power than conventional systems of comparable performance. That improvement in energy efficiency is the result of advances in individual components and--equally important--improvements in overall system configuration.

Concern for the environment spurred automakers to create more efficient engines. But more-efficient engines mean less heat for warming vehicle interiors. Heating units have had to become even more efficient to compensate for lack of the waste heat that conventional systems use.

We have developed a system for the Prius that gets the same performance as conventional systems despite the lack of engine heat available for the system. Ventilation loss--heat that escapes from the cabin as fresh air comes in--accounts for 60% of the heating load placed on air-conditioning systems. Our two-layer flow air-conditioning system re-circulates warm air in the cabin to raise heating efficiency.

By using a 50/50 ratio of fresh and re-circulated air we were able to reduce the ventilation load 50%. At the same time, we were able to achieve the same cabin temperatures possible with conventional systems. Warm cabin air has a high moisture content. So, simply re-circulating the cabin air would fog up the windows. The new system sends re-circulated air out at foot level. Drier fresh air flows near the windows, which prevents moisture from condensing on the glass.
[/b]

no worries, jmann found the archive!

[John in LB]

Just a quick question. A careful reading of how it works says that, for heating the interior cabin, an electric pump is used to circulate the hot water from the engine when the engine is not running.

I had read on other posts that the Prius had electric heaters to be used when the engine is not running.

Given that I have a 2006 model, which is it? electric heaters or electric pump? Electric heaters would use a lot of battery juice, whereas electric pump would use a nominal amount.

[seasalsa]

<div class='quotetop'>QUOTE(John in LB @ Jan 29 2007, 02:10 AM) [snapback]382209[/snapback]</div>

Just a quick question. A careful reading of how it works says that, for heating the interior cabin, an electric pump is used to circulate the hot water from the engine when the engine is not running.

I had read on other posts that the Prius had electric heaters to be used when the engine is not running.

Given that I have a 2006 model, which is it? electric heaters or electric pump? Electric heaters would use a lot of battery juice, whereas electric pump would use a nominal amount.
[/b]

Both! The electric heating elements work at startup before the ICE is warm. After warm up when you stop at a light the electric pump ccntinues to circulate hot water while te ICE is off.