I notice that whenever I'm driving at very low speeds (ex leaving a parkade with little or no pressure on the gas peddle) the realtime fuel economy guage shows the worst possible reading that it is capable of displaying. Couldn't they have designed the IMA to run in EV at very low speeds since electric motors provide good torque from a stopped position? Or is the Civic electric motor not large enough to provide the necessary torque?

 

The 4th gen IMA design does lend itself well to that type of EV-only operation at low speeds.

Yes, the ~20 HP electric motor and its relatively smaller battery pack is not capable of propelling and sustaining the vehicle for any practical distance as for example, the Prius does. It does make up for it though, as not even the Prius can drive on electric for very long either before the gas engine starts.

In any case, the IMA architecture would have to evolve a little beyond its current parallel arrangement to achieve that.



Cheers;

MSantos

 

'They' did, just not in the car you own. You should have bought a Prius!

On the other hand, I can drive the HCHII at most speeds of 30mph and up to about 50 and get around 80mpg on a flat road for extended distances, which the Prius can't do. And unless you accelerate very, very slowly with the Prius, the gas motor kicks in.

Both cars approach fuel economy from different directions but average out to be about the same.

 

You can only do EV in the HCHII at speeds of 10 MPH and above.

I wish I could lower that number! I encounter a 3 mile stretch of nasty traffic on my afternoon commute. Sometimes traffic crawls along at just below 10... and my mileage suffers. When it "zips" along at 15, I can grab EV mode and boost my MPG.

 

exactly what kind of conditions is your car in when it goes EV only?

 

When moving above 10 mph on level terrain (easier above 15), just take your foot off the gas. After a second, when the instant MPG gauge comes on up to near 100, put your foot back on and give it a quick application of maybe 10% throttle. It takes a little practice, but if you do it right, you'll see the charge meter showing white bars but the instant MPG guage still pegged at 100 mpg. THIS is "EV" mode! You can have from one to four bars this way. If you stab the throttle too hard... or go above four bars... or drop below 10 mpg, the engine will run again and your instant gauage will drop.

I've run in "EV" mode for over two miles. I've also gotten into it at anywhere from 10 mph up to 50. It's easiest to hold in the high teens and 20's (mph).

Practice makes perfect! I find EV mode very helpful in my traffic. I have one three mile stretch that crawls at 10 - 15 mph. For this stretch, I can get infinity mpg!

Enjoy!

 

Do the RPMs of your engine go to 0?
you described "you'll see the charge meter showing white bars"... isn't that just the color of the normal charge meter?

 

Yes, and at 7 MPH and below you can usually get the autostop to kick on. If the terrain (level to a slight downhill) and traffic conditions are right (aka barely moving traffic), I can get the autostop to kick in at 7 MPH and keep moving with autostop engaged. One time I did this near a top of an incline right when traffic decided to pick up a little. I got up near 20 mph while still "autostopped" before traffic started to clug up again to nearly stop and go.

Beware though, the traffic behind you is going to wonder what the fruitcake you are doing and may honk or show you one of their fingers, etc. So in your quest for awesome gas mileage, remember that you need to compromise a little bit for all of the irrational people on the road.

 

RPMs will not change in EV mode because the electric motor is mounted to the engine's output shaft. Thus the electric motor and engine *always* turn at the same RPM, and they're both turning (at a speed determined by the trans) whenever the car is rolling and in gear.

You have to look at a *combination* of indicators to read whether you're in EV mode or not. The only time the charge/assist indicator shows 1-4 (white) bars of assist *and* the MPG indicator shows 100 is when the car is in EV mode. If you're seeing 1-4 bars of assist and some other MPG indication, you're not in EV mode (that is, the engine is still receiving fuel and spark and the valves are still operating), but instead in power-assist mode where the electric motor is adding its power with the engine's. If you're seeing 100 MPG and the charge/assist indicator shows (green) charging bars, the engine is not running (no fuel/spark, valves all closed) but the electric motor is not driving the car either, instead charging the batteries. Obviously, you'll only see this condition when the car is coasting (usually either from deceleration or a downhill).

Almost always, you can only enter EV-mode by mostly or completely letting off the throttle and then *feathering* back on. You'll see MPG climb, then a couple charge/assist bars of charging, then no bars either way, and then the assist bars. If you move your foot on the throttle suddenly at all either way, you'll lose it.

By the way, on my daily commute I have a long (2.5 mile), medium-grade (~3%) downhill, frequently with a strong tailwind. I drive that stretch of road at 71-72 mph. The car usually enters EV mode 2-3 times on that downhill for ~ a quarter mile at a time. I was really surprised the first few times it did this (that godlike hybrid-driving feeling) because Honda doesn't suggest it will do this. But I've found the EV system a lot more flexible than Honda claims, engaging at anything between 10 and 75 mph if the conditions (including state of charge) are right.

cheers --
doug