DOES ENGINE RUN WHEN AC IS ON??

<div class='quotetop'>QUOTE(Norman H. Renehan @ Aug 6 2006, 10:42 PM) [snapback]298894[/snapback]</div>

The Prius engine does not need to run for the AC to operate. Both the Prius and Camry engine will eventually have to run to keep the HV battery charged enough to keep running the electric compressor and fans, however. But for short stops, the engine in both cars can stop running while AC continues to do its thing.

 

With the A/C electric compressor on, the ICE will only start to maintain the NiMH battery pack above 40%. I've been stuck here in traffic on one of our never-ending summer heatwave +35 C days, and the battery charge will eventually go pink. The ICE will then start to maintain slightly above that point.

I test drove a HyHi early summer and can also confirm the ICE will stay off with A/C on, if the battery SOC is high enough. Can't comment on the HyCam as I haven't driven one yet.

 

I had my Power on for quite a while with the A/C running when I first got the car...July 17...to download all the phonebook stuff....mostly in electric...

t

 

<div class='quotetop'>QUOTE(jayman @ Aug 7 2006, 05:41 PM) [snapback]299342[/snapback]</div>

Jayman nailed it...A/C kills fuel economy. Period. There are ways to lessen the impact but there is no free lunch kids. Gen 1 pri runs the ice with a/c on and kills mpg. Gen 2 will not IMMEDIATELY run the ICE but if you sit a while with A/C on the hv batt goes down, this eventually causes the ICE to kick on before it would with A/C off. Extended A/C run at a stop will cause ICE on. Much better than Gen 1 and FF only cars, but not free.
Defrost on all Yoda's is linked to the A/C even if the a/c mode is off. Anytime defrost is on, a/c is cooking. Defrost not a/c is my regional problem. 100* about 10 days a year. We worry more about wipers.

 

That's one of the beauties of electric A/C. If the compressor is a
mechanical parasite off the engine, you wind up burning off way more
kilowatts of HEAT from fuel just to get a lousy kilowatt or so of
cooling capacity. With electric, the engine can run intermittently
and at higher load and better efficiency to replenish the battery.
Just like it does to push you down the road, in fact...
.
_H*

 

<div class='quotetop'>QUOTE(hobbit @ Aug 8 2006, 09:10 PM) [snapback]299950[/snapback]</div>

H

Imagine how efficient home central A/C would be if it employed a variable speed compressor motor. The house I used to have in the burbs I had a Bryant Puron two speed, and that alone made a huge difference in my summer cooling cost.

Compared to similar size homes on my street, try 1/2 the cost to cool! I also made sure the ductwork was sealed with plenty of aluminum foil tape, and also insulated with R-12 mineral wool insulation.

When I built the new house at my hobby farm around 3 years ago, I put in another Bryant Puron 2-speed air conditioner. The only other person in that area with lower energy bills has a ground source geothermal system, and his bills are only slightly lower.

If he sealed and insulated his ductwork, he could probably lower his energy consumption a further 10%.

j

 

the A/C on the Classic is just like any other car, but when the compressor cycles off the ICE stops and I've had it off more than the 2k4's ICE in hot weather and in traffic and the battery in the pink. The electric compressor runs when ever the A/C system is on, high and low speed as required by the expansion valve in the evaporator and as such draws current from the HV battery all the time. Once the battery is down to pink the ICE starts and runs more than the Classic with the A/C compressor cycling on and off. Once under way and the ICE is running it's the same on both and I think the Classic does it better without the conversion to HV Battery charging better than the 2k4, the ICE in which seems to labour when the battery is low and charging. This is one area where I think the hybrid compressor on the Accord hybrid is a better bet, when the ICE is running it's clutch is engaged and when the ICE is stopped it's electric driven. As the ICE is running or spinning to protect the PSD at hiway speeds have it run the compressor. When ever your accelerating to start off or the first 5 minute cycle to S4 have it power the A/C compressor. Energy conversion from gasoline to electricity is less efficient that just powering the compressor. My 2 cents

 

I live in a very hot desert, 115 to 120 for a lot of the summer. How long before the car would overheat if you had AC on parked? If I let it run in my driveway to cool down say for a couple minutes, what do you think would happen. Not going to try it but just trying to figure some limits on this thing. Thanks.

 

<div class='quotetop'>QUOTE(GreenFarmBoy @ Aug 9 2006, 01:38 AM) [snapback]300074[/snapback]</div>

The engine will never overheat because most of the time while you're sitting the engine won't be running. The engine runs only when needed to keep the battery charged. The A/C runs as needed to keep the cabin cool. No problem. Of course you'll burn fuel doing this, but it does not damage the car.

In fact, note that in hot weather you *must* run the A/C to keep the battery cool! The cooling vent for the battery and its associated electronics is inside the cabin, because the battery system must be kept cooler than can be done by outside air. If the battery system gets too hot the battery can't charge or discharge as fast as it should, and fuel economy (and possibly battery life) will be reduced. Rule of thumb: if you are uncomfortably cold or hot, the battery is also.

 

<div class='quotetop'>QUOTE(GreenFarmBoy @ Aug 8 2006, 11:38 PM) [snapback]300074[/snapback]</div>

if you did this a first start up the ICE will run anyway, and will help charge the HV battery and then shut off and if the ICE gets to warm the cooling fans come on to cool the ICE and take the heat out of the AC system. Nothing to worry about.

 

<div class='quotetop'>QUOTE(IFixEm @ Aug 8 2006, 06:51 PM) [snapback]299936[/snapback]</div>

I routinely spend about 30 minutes parked with the A/C on. I tested the effect of doing so on mileage. The ICE cycles on for about 30 seconds once or twice during that time, and I was unable to tell a difference in my mileage in weeks where I did that five days in a row and weeks where I didn't do that at all. I suspect in my case I'm storing enough electricity in the battery that I'm not using to full advantage.

 

<div class='quotetop'>QUOTE(jayman @ Aug 7 2006, 08:41 PM) [snapback]299342[/snapback]</div>

The HyCam and the Prius run the same, as in, the ICE will stay off until it needs to recharge the Battery. In the HyCam, you have longer to go, and if you are running around in stop and go traffic, it will get to green far faster.

 

I just got my '06 and I had to sit in the driveway for 20 minutes while the XM radio activated. The ICE stayed off the entire time (I was just under where the battery indicator turns green when I started). I am pretty sure that with the electric multi-speed compressor, the entire quibble over lost mileage is pretty moot. Yeah, maybe the ICE runs a bit more to charge for the AC, but really is it enough to care about, at least in the newer cars?

 

Although having a belt driven compressor would imrove the energy conversion, the loss is overtaken by the improved efficiency of using a variable speed compressor which you can't achieve with a mechanically coupled compressor. At full speed, there may be no difference, though Toyota claims that the new system is more efficient. But most of the time the compressor is not running full speed.

 

<div class='quotetop'>QUOTE(DanMan32 @ Aug 10 2006, 01:02 PM) [snapback]301034[/snapback]</div>

it might not be running at full speed but it's still running and drawing current from the HV battery which has to be replaced and the only place it comes from is gasoline.

 

as long as the Hybrid battery is "high" enough or charged up enough, the ICE wont run

 

and as a little side note...part of the reason all the hybrid mileage from the Gov is dropping is beecause they are actually gonna use the AC when running the test...like oh 90% of the population, used to run without it which is the real reson for an electric compressor to reduce the drag and squeeze out an extra mpg on the sticker

 

<div class='quotetop'>QUOTE(buyaninsight @ Aug 13 2006, 08:05 PM) [snapback]302815[/snapback]</div>

all mileage estimates will drop as a result. Every vehicle that has an EPA estimate will drop, can't help but.