This is my first post.

I've had my 09 Civic Hybrid for about 3 months now. I drive from Atlanta to Birmingham and back 3 times per week and have been only getting around 39-40 MPG going around 70-75 MPH. Yesterday ( for some reason ) I put my A.C. on auto when I left Atlanta, and when I reached Birmingham, I was getting 45.5 MPG. I can't believe the difference.

Today, I went there and back and did 45.5 MPG again.......can it be that easy? What elese can I do?

Tom

 

First, welcome and congrats on the new HCH!

One of the great features of the car is its "hybrid" A/C. The compressor will operate on electric power only when there is a moderate cooling load. Under heavy demands it adds the belt driven mode which puts an extra load on the motor. In "auto" the system will use the electric only mode as much as possible. This will also give you some A/C while the motor is in 'auto-stop'.

One technique is to set the temperature at the higher levels (80F) until you notice the fan slowing down, then gradually lower it to what you find comfortable. This way you avoid using the belt driven part of the compressor as much as possible.

There are many other factors that will affect your mileage but a steady foot and moderate speeds do wonders. Check out the many other posts on this subject and you will find that 50+ mpg is easy to achieve in the summer.

Cheers,

Roger

 

I would say you had a good tailwind or something else going on in your favor. A/C use in a HCHII be it in Auto or Man. mode kills MPG. Last test I did was a solid 4.8 mpg hit with A/C.

 

Maybe the car's engine is finally broken in? That usually increases mileage. The AC use may just be coincidence. I notice a small hit to my mileage when AC is on (about 3-5MPG).

 

Remember that auto AC will cycle between electric AC from battery power and AC driven off the engine. My wife regulated the AC with the fan rather than the auto mode last week and ended the trip with lower FE and a lower charge on the IMA.

 

I've tried using AUTO for the AC, but it seems to exit AUTO mode whenever I manually select RECIRCULATE or alter the fan speed. There are times when I prefer RECIRCULATE due to smelly vehicles or in traffic, and there are times when the AUTO fan speed is too high. I have tried playing with temperature settings to lower fan speed, but if that works it still won't help with the RECIRCULATE issue. Any ideas or tips?

 

I think I have a Wednesday car. The only issue I have had so far was the control arm issue. Right now I have the a/c cranked and I usually do 75 mph and I consistantly get 47 mpg, and that's with a full stereo (two amps) running. On the flip side my best has only been 58 mpg and that was last Nov. when gas was really expensive and I drove it the way it was intended. I don't know how folks are getting 65 + mpg as it was very hard for me to get that.

 

Steve and others,

I've been confused in the past by the "auto" mode on my Accord with climate control. After at least a year of trial and error, I finally figured out the "logic" of the system. So when I got my HCH, I had an idea of what happens with its system. I read the manuals for both cars very carefully and they never made it clear what actually happens.

When you select "auto" the system sets the fan speed, selects the vents to use, cycles the compressor (or heat) according to the temperature setting, and if the car is very hot, it initially goes to recirc but switches to fresh when the car cools to near the temp setting. Once you manually select any different function, the "auto" indicator goes out, however, all other functions remain governed by the system. If you want to "reset" to full "auto", simply push that button and start over.

One special feature I discovered is the sunlight sensor on the dash in front of the speedometer, near the base of the windshield. When sun hits the sensor the system directs cooler air to the center dash vents but doesn't blast your feet. All in all, this is a very sophisticated system, normally only found on high end models.

Avoid using the manual "A/C ON" setting if you can. However, I use the "A/C OFF" in mild weather to defeat the sunlight sensor trying to send cooled air when the outside air is already cool enough.

Starting at a higher setting until the car cools down and gradually lowering the temperature as you find the fan slowing down will reduce the load on the engine as you minimize the use of the belt-driven part of the compressor. This is where some benefit to fuel economy will normally result.

Good luck,

Roger

 

Very informative read, Roger, thank you!

Jess