I would respectfully disagree. On the 06 Civic, I believe that to be definitely not true - Unless I read the KB and service manual specifications incorrectly.

To be more specific: As per specifications, the 06 HCH compressor uses a clutch mechanism that enables the DC scroll compressor to operate independently of the its belt-driven counterpart and by implication- the Gas Engine.
Consequently, this approach ensures that no load is applied on engine unless the climate control system enables pumping from the belt-driven side of the same compressor to fulfill either of the two remaining operating modes.


Regards;


MSantos

 

This is from HondaNews\Civic website
http://hondanews.com/CatID2013?mid=2...41801&mime=asc

Civic Hybrid: Hybrid Dual Scroll Air Conditioning Compressor
A dual scroll hybrid air conditioning system reduces the load on the gasoline engine by using a combination of engine power and an internal electric motor to drive two air conditioning compressors. These compressors can act independently or together as dictated by the cooling needs of the Civic Hybrid's automatic climate control system.

Under normal conditions, either of the two compressors cools the interior cabin individually depending upon cooling needs and the charge state of the IMA's battery pack. On warmer days, the 75cc engine-mounted compressor acts as the sole source of air-conditioning, while the 15cc motor-driven compressor is in action when the climate control is maintaining a steady temperature or the car is idle-stopped.

Under extreme ambient conditions, cooling is provided by the 75cc belt-driven compressor attached to the engine and the 15cc, 144V motor-driven by an internal electric motor. When the air conditioning system is forced to use both the gasoline engine and electric motor, the Civic Hybrid's idle-stop feature is temporarily disabled until cooling needs are reduced.

I hope that helps in understanding how it works.

There is plenty of other good information on Civic Hybrid at this site.

Mike

 

Ok the Civic AC unit reduces the load on the ICE because it is only running half capacity, not because it is electric.

Belts are a fairly efficient way to transfer power and I wouldn't be surprised if a belt drive was more efficient than first converting the mechanical motion of the ICE to electricity (with IMA) and then converting the electricity back to mechanical motion with an electric AC compressor.

An electric AC compressor would be easier to control and could be used when the ICE is off.

I'm not saying electric is bad, the Honda gen 2 AC design is fantastic and is more efficient, just not for the reasons some of you seem to think....

Perhaps "someone" with an engineering background could verify one way or another..??..

 

Hummm... good point.

Would it help if I am a professional engineer (20 year career) with access to Honda's technical literature?


Cheers;

MSantos

 

MSantos,

I knew I was asking you for a good reason. I am also an engineer (mechanical) with 20 years experience, this year in fact.

 

Welllllllll, not really. I was guessing before but now I've researched and belts are in fact more efficient.

http://energyconcepts.tripod.com/ene...pts/vbelts.htm

You seem to be buying into the marketing hype instead of actually thinking about how electrical loads cause mechanical stress on the ICE via the alternator (in a non-hybrid) or in the case of a hybrid via the IMA or HSD. I don't doubt that you can produce a Honda paper that seems to dispute my claims but your interpretation of "no load" would be in error.

If the Honda's electric AC puts no load on the system what-so-ever, why is my home electric bill so high during AC season?

Also even the fancy new honda system gets more of its power from the 75cc (not electric) compressor and only gets a fraction from the 15cc electric compressor.

I promise that the primary advantage of the new system is to keep the car cool during an autostop.

 

From:

http://www.autobodynews.com/Sections...s%20story.html

 

Lakedude- I see. Please forgive my "ignorance" but I don't think the subject of this thread was focused on efficiency of the DC half vs Belt-driven half in the 2006 Hybrid scroll compressor. Let us say that we're beyond the rather academic and elementary nature of such a discussion.

Instead, I believe the thread concerned the impact on fuel economy when operating the 06 Civic Hybrid under certain managed conditions. As we stated, when operating the AC in these conditions, the 06 Hybrid is able to maintain the cabin temperature without imposing significant (or even measurable) duty on the gas engine and its fuel economy. My effort was geared towards explaining why that is possible - at least from a technical perspective - without of course - copying word-for-word from the technical manual. That would be plagiarism, right?

So I apologize if I offended or aggravated you. That was NOT my intent. But I also would not like the topic to degenerate into a discussion of mechanical basics. To ensure this, I will respectfully sign off from this thread.

Cheers;


MSantos

 

Lakedude,

Basically it comes down to this: If you are under driving conditions where you have managed the SOC properly and can take advantage of transfering the cars kenetic energy into potential energy via battery charging through regenerative braking, you are basically getting all or most of the energy for running the A/C for free. This would be energy basically thrown away as heat in the brake pads if the car were not a hybrid. This depends on a lot of factors such as the outside temperature, distance/time of the trip, starting inside temperature, type of terrain traveled, and temperature setting of the A/C system. I saw a huge difference in gas mileage when the A/C sytem was set in the low 70's on Auto and I did not manage my SOC correctly. The results of this was that the battery was constantly at 4 bars and the car could not get ahead of the curve. This resulted in forced regen most of the time and very poor gas mileage of approximately 38mpg. I am sure the belt drive off the ICE was on full time as the car would not auto stop either. All this was with an outside temperature of 100 deg. Once I took the advice of others here and started driving the first mile with windows open, then set the A/C to 86 for a few miles and then lowered to 80, the car cooled off well and remained comfortable. I just got 49 mpg average yesterday@102 degree outside temperature on a 200 mile trip with the A/C on the entire time. Obviously Msantos has some valid points as the A/C system allows for good cooling performance under almost all situations, but it barely effects gas mileage if you can keep it in the electic only mode while maintaining your SOC high. If you can keep your SOC high without forced regen, there will be almost no energy supplied to the A/C system from the ICE, hence no negative effect on gas mileage. You are correct that electical energy is not free (ie horsepower), but where the energy is supplied from is the real issue here. Again if I am on top of a 12,000 ft mountain I could drive down to the bottom for probably 30 miles and get 150+mpg with the A/C blaring the entire time. Why, because I simply traded the potential energy of the height using gravity for free charging energy in the battery. If fact under those conditions I could probably just roll down the hill with the car off for almost infinite mpg. The trip up would be fun though.

 

I agree that we have side tracked this thread and need to butt out because we are off topic, I'll contact you guys by PM when I get a minute. Sorry if I came on too strong. Sorry also for side tracking the thread, bad moderator BAD! I just spanked myself....