How does 2006 Civic's EV mode work?

[ElectricTroy]

The New 2006 Civic has an EV-only mode.

How is that accomplished, and can the same technique be used on the insight?

[b1shmu63]

Essetially the electric mode deactivates the valves and turns the pistons into air spings. In this mode it takes very little energy to turn over the gasoline engine. Regeneration efficiency goes up and friction goes down to the point where most of the energy from the electric engine gets to the wheels. The practical application of this system required a whole lot of research, so we won't see it on the present Insight.

[Rick]

No the Insight does not have it. Really it's pretty limited, but happens where it's probably the most beneficial. You have to be doing 10mph already at least and moving along at a constant speed and light throttle. They say it will work up to 35mph, but I've found it's really only good for 30mph on flat ground. Sometimes the car will willingly use it, sometimes you have to try and make it do it by letting off the gas until your in that "valves off" mode and just coasting then very slightly ease your foot back in to it at which point it will show between 1 and 4 bars of assist and the mpg gauge will be pegged at 100mpg. Any more than 4 bars of assist (keep in mind 1 bar on the civic is at least 2 on the Insight) and it kicks the engine back in.

How about a Civic drivetrain in the Insight then?

[JohnHeller]

There's an excellent Honda animation explaining the '06-'07 Civic's IMA system at http://world.honda.com/HDTV/news/2005-4050705b/

-John

[ElectricTroy]

Originally Posted by Rick

You have to be doing 10mph already at least and moving along at a constant speed and light throttle.

That seems a lot of engineering work/research plus mechanical complexity for minimal benefit (EV between 10 and 30).

So if I'm driving a New Civic Hybrid, I can't use electric-only starts like the Prius does?

[b1shmu63]

The Prius ability to crawl along in electric mode is a inherent function of Synergy drive, and not necessarily an advantage for the Prius overall.

What Synergy drive gains at a crawling pace it loses at highway speeds as it is more lossy than a conventional transmission. The Prius manages to eek out 1 or 2 percent greater overall gas mileage in real world conditions, and this is probably due to storing the engine coolant for preheating the engine.

Not only is the Prius a more expensive car to purchase, but it has other disadvantages in my opinion.

Synergy drive is inherently more complex technically, making it difficult to service if there is a problem, without specialized training.

The Synegy system is inherently more expensive, due to the requirement for two electric motors having a combined electrical power output about 3 times that of the IMA motor.

The Synergy batteries are of necessity more expensive and larger.

The ICE is smaller making it less powerful in mountainous driving or pulling a trailer. (OK I know you aren't supposed to pull a trailer)

Unlike IMA assist, if the electronics fails for the Synergy drive system the gasoline motor stops.

Likely the next generation of Prius will outshine the Civic, but they are not there yet IMHO. The Prius advantage at that time may be due more to using silicon carbide switching transistors and lithium batteries than an inherent advantage of Synergy drive.

One might still prefer a Prius based on notability, brand loyalty, style, gadgetry, stowability, and ones personal taste in handling but I wouldn't make my choice on creepability unless I drove mainly in traffic.

[Dougie]

I was thinking today about what sort of mileage Honda might be able to get from the new small Insight replacement, considering ten years of experience with hybrid systems. One obvious answer is to use EV mode more aggressively. If so, then I have this question:

If you have an EV mode with a Honda hybrid drivetrain, and you wanted to be able to get started from rest, what sort of ratio would the CVT use?

If the CVT chooses a high ratio (like low gear in the manual), then the internal combustion engine is going to be turning fast, thus giving more friction. If the CVT chooses a low ratio, the ICE will be turning slowly (a lot more slowly), so you get less friction. But then the electric motor also turns slowly, and maybe it doesn't have enough torque to get the car moving.

[ikhoudvanu199]

Originally Posted by Dougie

If the CVT chooses a high ratio (like low gear in the manual), then the internal combustion engine is going to be turning fast, thus giving more friction. If the CVT chooses a low ratio, the ICE will be turning slowly (a lot more slowly), so you get less friction. But then the electric motor also turns slowly, and maybe it doesn't have enough torque to get the car moving.

ahhh...but the joy of electric motors! unlike ICE(who need to rev higher to get more torque)...electric motors generate all their available torque from 1rpm

and another downside to synergy drive...with the ability to drive from a stop with EV only, it has caused alot of shops to refuse to service hybrids under the pretense of: "if it will run without the engine on it will run without oil." obviously some idiot mechanic forgot the oil in a synergy hybrid, gave it back to the customer, and, most likely some very bad happened once they hit 25 or so mph!

[Dgate]

Regarding the shuting down of the ICE on the Honda civic, I wonder why they didn't consider a free wheel device between the engine and the electric motor instead of valve deactivation.

If the ICE were turning slower than the IMA or was stopped the IMA would drive the car and when powered up and matching the rpm of the IMA the ICE would drive the car too higher speeds.

In other words the IMA would be the primary mover for starting and low speed EV drive with the ICE coming up to rpm for faster driving. Imagine the drive of a bicycle with the pedals being the ICE and an electric motor driving the front wheel,you start off not pedaling but the electric motor moves the bike up to speed
then you start pedaling and when the pedal speed matches the EV wheel speed the free wheel locks in and you add to the speed by pedaling harder and faster.

No clutch would be required and shifts on a
manual would be accomplished by steering wheel paddles with electric activation of ratio change controlled through a CPU.
PS an electric motor developes its max torque from zero RPM not 1RPM.
DGate