Looked at Hondas today.

Re: Looked at Honda's today.

Yeah, the commute is a different drive from the weekend blasts.

 

Re: Looked at Honda's today.

Nope. But apparently it was enough to prompt Toyota to design the system the way they did.

 

Re: Looked at Honda's today.

It's more than just not being to stop the engine when you need AC and you're not moving - the extra belt length and AC compressor always sucks up extra drag whether you're using the AC or not since it's physically coupled to the engine.

If the engine is spinning, the AC compressor wheel is turning (even if the actual compressor isn't engaged).

 

Re: Looked at Honda's today.

The Classic Prius had belt-driven A/C system back in 1997. In 2004, the Iconic Prius was introduced with the electric A/C. According to the Denso engineer's presentation, the electric A/C system improved MPG by 19% in the summer.

Note that the amount of power required for both systems (belt and battery) are about the same. The difference is that the electric A/C allows the ICE to halt.

6 years later, Honda is still using belt-driven gas powered A/C in the Insight-II.

 

Re: Looked at Honda's today.

Hard to read just the graphs without more details about what is being compared. It looks like the size of the compressor was reduced by 40-50% as part of the savings.

Agreed that the same power is required but note the battery needs to be charged first in the E A/C and that extra conversion (not present in conventional A/C) also results in energy loss.

 

Re: Looked at Honda's today.

Right, despite all the conversion loss, the end result is about the same as direct belt driven mechanical design.

The benefit of electric A/C is huge. It disconnects from the ICE and it opens a wide range of opportunity. To list a few:

• ICE does not need to be running just for A/C
• HV battery can be charged during low load highway cruising
• HV battery can be charged from regen braking

All those resulted in 19% better fuel economy in the summer.

Per the presentation, it takes about 1.5kW to run the A/C. If I recall correctly, the ICE need 3kW to keep it idling. That's a big waste to run ICE just for the A/C.

 

Re: Looked at Honda's today.

Not only that, but by not being driven by the engine, the speed of the compressor is not dictated by engine speed (notice how your typical car has to idle faster with the AC on), but dictated by AC load - they can simply vary the amount of juice going to the compressor. Or if the compressor is the most efficient at only one speed - always run it at that speed.

 

Re: Looked at Honda's today.

Dress made a great point. Prius' electric A/C compressor is variable. It only needs to work as much as needed.

For the Insight-II, if the A/C is too cold, hot air from outside is mixed to give the temp you set. It has no choice because the compressor is tied to the ICE.

For the Prius, electric compressor just slow itself down (consuming less energy) to reduce coldness. It makes sense and that's how it should be.

 

Re: Looked at Honda's today.

Ah, that's what the cycle efficiency is referring to in page 6 , 80 vs 100 due to this, but note the 35C bar chart, conventional AC still wins in hot weather due to the other losses I mentioned in previous posts.

 

Re: Looked at Honda's today.

Wow, look at the graph on page 4: the temperature and humidity curves for the electric drive are almost flat.

 

Re: Looked at Honda's today.

That's only when HV battery is low and the ICE is forced to run. This does not happen often and the ICE shut down after it recharges the battery to a threshold.

For the Insight-II, it always has to run the ICE when the A/C is on.

 

Re: Looked at Honda's today.

The consistency of electric AC to maintain temp and humidity is amazing. The ICE is off and shows no revving up and down like a belt driven AC.

 

Re: Looked at Honda's today.

My wife drove her new Insight home in a rainstorm, and had the AC on as a defogger.
I was sitting next to her, and didn't notice it was even on. Pretty quiet car. A bit smaller inside. More conventional dash and floor mounted gearbox. Definitely better styling than my Prius II. Has that eco mode, too, like the III.

I must agree with some of you that prefer the Prius--as a Prius owner. But my wife actually prefers the Insight--she thought the Prius was too big, and didn't like the unconventional dash. She also likes Hondas, since she's been driving them a long time. I think the Insight is a bit more nimble, and maybe feels more like the Civic she drove previously.

The other thing was PRICE. She got a great deal on the Insight--priced more like a conventional car (around $18K not including trade) and about $4K cheaper than the Prius. :rockon:

 

Re: Looked at Honda's today.

Yes, but the energy loss of that ICE->HV battery conversion is part of the overall energy efficiency equation, isn't it ?

Note the page 4 graph shows the testing conditions were start/stop traffic less than 30mph. Question is then how efficient is the ICE->battery charging under those conditions ?

 

Re: Looked at Honda's today.

The E A/C is running a constant speed so this is totally expected.

About the page 4-5 graphs, it is curious the model used is for an SUV not for the Prius sized vehicle.
In addition, no ambient temperature is listed but one can guess it's between 50-68 which is hardly a condition for stress testing an A/C.

 

Re: Looked at Honda's today.

Of course. Since the AC is disconnected from the ICE and the HV battery can be charged at optimum conditions, you cannot narrowly focus on conversion loss. You'll have to look at it from the whole system working together.

There will be multiple scenarios and you'll have to average it out. There will be worse and best cases. However, overall electric AC is an improvement in fuel efficiency and the consistency quality it provides.

 

Re: Looked at Honda's today.

Can' help not to mention, I got my Prius 2010 for $18k after some strugle and here is how, sticker price minus $4.5k C4C Dodge Intrepid 1997 with 200k miles minus $500 PA rebate that I found out about in this web site...

 

Re: Looked at Honda's today.

There are times where I wholeheartedly agree with this. But still I have to echo everyone's sentiment about the Insight II and its omission of an electrically powered AC compressor. This definitely helps ding its FE hard when it comes to keeping the cabin cool in the warmer days with no option to stop the ICE or execute on its basic hybrid features (ICE off glides and ev-glides).

Now, on this note: I am not a fan of a completely electrically driven setup either, unless it is improved with efficiencies similar to what Toyota delivered for the 3G Prius and the HS250h.

In the absence of these improvements, I believe the HCH-II (since we're in a Honda hybrid section of the forum) delivers the best and most effective approach by having a truly hybrid scroll compressor that can be either run by the ICE, battery pack or both.

Too bad Honda decided to deprive the Insight II of this (and other) features.


Cheers;

MSantos

 

I bought and owned a new 2006 my first Honda, I have to say it was the cheapest made car i ever owned, in 6 months the black fabric seats turned gray, the arm rest was worn and the car floated on the hwy like crazy, i bought new no more Hondas for me.