Honda Insight Forum banner

1 - 20 of 21 Posts

·
Registered
Joined
·
157 Posts
Discussion Starter #1
When I use air conditioning in my 2002 Insight, I can tell it really takes a toll on the mileage and power. I need to use a lot more assist which uses more battery too. At freeway speeds it's not too bad, but with a lot of stop and go, the battery can get run down pretty quick. I find myself hitting the econ air on/off button when I accelerate or go up hills and then hit it again when I am going down hills or cruising.

I wish there was a smarter econ mode, one that would turn off the compressor when power is needed and turn it back on when there is extra power available.
 

·
Registered
Joined
·
1,240 Posts
I guess you're missing the point of ECON mode. It was only designed to allow engine shut off when the car is stopped. Yes it would be nice if the car had a smarter ECON but it doesn't.

It would be better if Honda just gave the Insight electric A/C, that didn't need engine power to operate, like other Hybrid models now have.
 

·
Registered
Joined
·
89 Posts
My '75 Toyota Celica was smart enough to kick out the A/C compressor when you floored the gas, I agree that they could do the same thing with our Insights.

Regards,
 

·
Registered
Joined
·
1,240 Posts
hawkGT647 said:
My '75 Toyota Celica was smart enough to kick out the A/C compressor when you floored the gas, I agree that they could do the same thing with our Insights
I would bet the newer A/C design in the Insight is more effient now than the system in that old 75 was with it's feature.
 

·
Premium Member
Joined
·
4,942 Posts
And how much more efficent would it be _with_ the feature. ;)

Shouldn't be too hard to design. Either plumb in a MAP sensor and make an additional "AND" condition for compressor on or use the existing MAP signal.

You'd probably want some type of potentiometer for the compressor trip out point so it could be adjusted.

Cost is the consideration. And the real payback in gas savings will be measured in the 10's of thousands of miles.
 

·
Premium Member
2001 5S "Turbo"
Joined
·
10,900 Posts
Just picked up a "vacuum switch" that can be used as either "current on or current off".

The amount of vacuum used to actuate the switch is also adjustable from .4 to 30 in. Now I have to figure out what amount of vacuum to use to activate the switch. The AC will automatically shut off during acceleration either in or out of econ mode because of low vacuum.

The switch will be installed in series with the AC compressor.
Two years ago I installed an AC compressor "on" light, and yes mileage does drop when the light is on.

I always run in econ mode and shut off the AC on acceleration with the "button", this switch will save the finger.
 

·
Registered
Joined
·
466 Posts
yes, please some more info about both the switch and where you tapped into the compressor wiring. i plan to use a blue LED on the dash to see when the compressor is engaged, but i dont want to run a wire all the way up to the compressor. i would rather find the wire under the dash.

andy g.
 

·
Premium Member
Joined
·
4,389 Posts
I have provided a power transistor switched output on the MIMA_C board, that could easily activate an A/C kill function. I am already measuring the MAP signal, and could activate the switch whenever the MAP voltage raises to a setpoint, similar to the assist activation point.
I was also thinking that the same logic could activate the MIMA standby mode and kill background charging when the same MAP setpoint is reached, therefore allowing all hill climbs and strong accelerations to have minimum parisitic loads.
 

·
Premium Member
Joined
·
4,942 Posts
Willie Williford said:
Just picked up a "vacuum switch" that can be used as either "current on or current off".

<snip>
How about it Willie :?: Will you post the source for this switch. Its the kind of mod that's right up my alley, simple and cheap ;) (hopefully).

AFAI remember about 10" Hg was the set point for the CRX but if your willing to sacrifice some additional cooling and your local terrain isn't too hilly then slightly higher would have a greater MPG improvement.

HTH! :)
 

·
Premium Member
2001 5S "Turbo"
Joined
·
10,900 Posts
John;
I got the switch at a surplus electronic store for $4.00, "bench" checked OK using 12V as a power source and a vacuum pump for "suction". Can be adjusted from .4-30" vacuum. It can be used to open or close a circuit. (The "proof" in. is listed at 30, whatever that means. I think it means how much "pressure" the switch can handle without rupturing the diaphram) It is rather large, (3"X3") and from the size of the wires it looks like it would pass 25 amp easily. (12gauge?) (mfg. "Meletron" model #421B)

A good source for info on vacuum switches is:
http://www.nasonptc.com

Pre installation:
Numerous test runs, and watching my "vacuum gauge" closely I observed the following results:

There is usually a 2in. drop in vacuum when the AC is actuated, so you are close John, 10" of vacuum seems to be the best "cut off" point for the AC compressor with mountanious driving. A "hiper miler" would probably use around 15" as a "cut off" point.

From my research and reading "between the lines", I believe Honda gets their mileage figures running the engines in a 10-15 in. vacuum range (at the factory).

I will be hooking the switch up temp. and doing some prelim testing soon.
Connecting the wiring "at" the AC compressor appears to be the easiest, (can be done after removing the engine panels from underneath).
More later.........
 

·
Registered
Joined
·
7 Posts
A/C cuts off, engine (and driver) overheat, help

Hi,

I'm a little off your topic, but you guys seem to be up on the A/C operation. Keeping it brief, my A/C stopped working (appears clutch disengaged), and then engine starts to overheat. Honda looked at it, said the A/C was running TOO HIGH of pressure, they evacuated system, recharged with proper quantity of freon, and it fixed it for ... 24 hours!!

Suggestions?? It appears A/C quits first then temp rise, but they are close in time. Always normal A/C first thing in a.m. when it's COLD, which is relative here in Florida.

Thanks
Doug Cooley
 

·
Registered
Joined
·
242 Posts
You should be able to pick up a vacuum switch at almost any auto parts store for a few bucks. Don't know if it would be adjustable like the one Willie got. GM was using these switches on Rivieras (and possibly other models) in the 60's to cut the a/c off and give you more power when you floored it.

Along this same line - I'm having a more efficient refrigerant installed in the a/c in my S-10 this Thursday. If that install goes well, I'll take the Insight to the technician, have the 134a sucked out of it, and charge it up with 12A - a far more efficient refrigerant than 134a. Since 12A is far superior to 134a, there is less load on the compressor, therefor less load on the engine with the a/c on.

The Insight uses a scroll compressor, which uses a little less horsepower than a piston compressor. I don't know how much horsepower the compressor is pulling at this point - I would guess four at least - does anyone know? The 12a comes in at less than two to three hp with a standard piston compressor.

With a more efficient refrigerant, I'm looking for better cooling with less engine drag. I'll let you know how it works out. There is nothing at all wrong with the a/c in my car - it works like a champ - the best auto a/c I've had since my '66 Bonneville.
 

·
Premium Member
Joined
·
4,389 Posts
A quick look at the schematic shows that the AC compressor clutch is controlled by a relay that is in turn controlled by the ECM @ connector A pin 17.
That is the control point I will probably use to allow MIMA to shut off the AC on hills. Since the point will be pulled low by the ECM when the AC is on, An additional relay in series that is controlled by MIMA would be the easiest method to shut down the compressor. There are other control signals like the engine ready signal @ ECM connector A-2 that may shut it down when in the eco mode, and would likely be even easier to connect.
Will have to do a few test next time the back is opened.
Will be watching to see what Willie comes up with.
:wink:
 

·
Registered
Joined
·
242 Posts
Resist said:
Jim said:
I'll take the Insight to the technician, have the 134a sucked out of it, and charge it up with 12A
Isn't that illegal?
Uh, no, it isn't illegal. They have equipment to recover and store the 134a. There is no law saying which refrigerant you have to use in your car - although DuPont would like one, I'm sure. :evil: http://autocool-refrigerants.com/
 
1 - 20 of 21 Posts
Top