Civic hybrid 06 driving technic summary thread

[DigitalMan]

Originally Posted by NASAgineer

We really need better terminology for the HCH-II because people have been using the term 'EV mode' to mean several different things. I like Stephane's term, Zero Fuel Glide (ZF-Glide for short?). Even in ZF-Glide, there are three different modes.

1- ZF-Glide with regen.
2- ZF-Glide with NO regen or assist.
3- ZF-Glide with assist.

Agreed, maybe these acronym out as:
1- ZF-Glide with regen = ZFG-R (R = regeneration)
2- ZF-Glide with NO regen or assist. = ZFG-N (as in N = neither or none or neutral)
3- ZF-Glide with assist. = ZFG-A (A = assist)

[NASAgineer]

Originally Posted by DigitalMan

My intuition tells me that the most efficient way to drive the car is only using the internal comustion engine (ICE) with no electric boost. This is because power directly from the ICE to the wheels will be more efficient than power created by the ICE, converted to electricity (some loss), stored in the battery (some loss), retreived from the battery (some loss) and driving the electric motor (some loss). So, this would seem to argue that the best mileage would be obtained by avoiding "hitting the pack" (either charging or discharging the batteries) as much as possible. I think xcel recommended that in another thread; seems to make sense. Makes you drive like a slug ("slugging," as in ICE only, accelerating or driving slowly) and potentially subject to other drivers' road rage, but there you are.

I guess that would be true if you really could always just coast to stop and never incur any regen, but the vast majority of people will incur some regen without even trying in normal day-to-day driving. A good example is a stop sign at the bottom of a hill. There's no way you can go down that hill and stop at the sign without getting some regen. There are obviously many more examples of inevitable regen. In those cases it makes sense to USE the electrical power that you got from the regen. Everything you say about the inefficiencies in the electrical conversions is completely true, which is why you should adjust your use of assist based on the current battery level (anything above 5 bars can be used for 'free' without incuring any forced regen). Another way of putting it is to try to only use assist that is the product of inevitable regen.

[slajeune]

Hi All,

wow, lotsa good feedback. Digital Man, I fixed the "broken" braking! Sorry, English isn't my mother tongue.

As for using assist / not using assist, two sources of great information:

- Geoffrey (the first HCH-II hypermiller!) usese swift accelration at 2.5k-3k RPM for the city portion and then, a constant 1k RPM afterwards. It is very unlikely that you can accelerate in D at 2.5k-3k without assist from a standstill.
- While accelerating back from a glide, it seems that using assist to get back to speed had the best fuel efficiency (as per NASAngineers experiments)

As NASA said, it's all about using it wisely. In a purely city driving context, the battery will be able to stay at a resonable level throughout the trip.

As for the for terminology, I'm all for it. We can define all three if we need to. No harm there!

Thanks,
Stephane.

[DigitalMan]

Originally Posted by NASAgineer

I guess that would be true if you really could always just coast to stop and never incur any regen, but the vast majority of people will incur some regen without even trying in normal day-to-day driving. A good example is a stop sign at the bottom of a hill. There's no way you can go down that hill and stop at the sign without getting some regen. There are obviously many more examples of inevitable regen. In those cases it makes sense to USE the electrical power that you got from the regen. Everything you say about the inefficiencies in the electrical conversions is completely true, which is why you should adjust your use of assist based on the current battery level (anything above 5 bars can be used for 'free' without incuring any forced regen). Another way of putting it is to try to only use assist that is the product of inevitable regen.

Agreed. My interest is more about the efficiencies of accelerating from a stop than about ZFG. Best to accelerate with assist or to try to avoid it? Perhaps that will depend on whether you think you can get some "free" regen back once you get moving. Is assist in accelerating more efficient than without assist or does assist during acceleration just consume electricity to accelerate faster?

[DigitalMan]

Originally Posted by slajeune

Digital Man, I fixed the "broken" braking! Sorry, English isn't my mother tongue.

As for using assist / not using assist, two sources of great information:

- Geoffrey (the first HCH-II hypermiller!) usese swift accelration at 2.5k-3k RPM for the city portion and then, a constant 1k RPM afterwards.

No worries on the English, thanks for posting in your non-mother tongue, and a good little joke about it too!

As my neighbor with a new Ferrari points out, "swift acceleration" is a relative term in a car that goes 0-60 in 10+ seconds, but I get the idea.

[NASAgineer]

Originally Posted by DigitalMan

Agreed. My interest is more about the efficiencies of accelerating from a stop than about ZFG. Best to accelerate with assist or to try to avoid it? Perhaps that will depend on whether you think you can get some "free" regen back once you get moving. Is assist in accelerating more efficient than without assist or does assist during acceleration just consume electricity to accelerate faster?

Because of the way the car is programmed, I find it very difficult to accelerate without any assist at all because you have to be VERY gentle on the accelerator (even accelerating at 1500 RPM usually gives you some assist). Plus, even when accelerating gently, mileage is in the 20-30 MPG range during the whole pulse. When you accelerate slowly you spend more time in the pulse. I did some experiments (see this thread) and found that the sweet spot was around 2000 RPM, which gives you about 3 bars of assist. So, try to minimize assist, but don't go so far that you spend most of your time gently accelerating.

[CGameProgrammer]

I think "assisted glide" or "extended glide" are good words for it. The car always coasts without using gas (unless your speed is really low) so zero-fuel glide isn't the best term IMO.

Since you can't accelerate in this mode, and you have to already be gliding (zero fuel consumption) in order to activate it, it's just a way of extending that glide or assisting it... so I like those terms.

[ElanC]

Originally Posted by CGameProgrammer

I think "assisted glide" or "extended glide" are good words for it. The car always coasts without using gas (unless your speed is really low) so zero-fuel glide isn't the best term IMO.

Since you can't accelerate in this mode, and you have to already be gliding (zero fuel consumption) in order to activate it, it's just a way of extending that glide or assisting it... so I like those terms.

I agree.

Assisted glide. (AG)
Neutral (i.e. non-assist, non-regen) glide. (NG)
Regenerative glide. (RG)

should do it. The ZF doesn't tell us much.

[NASAgineer]

Originally Posted by CGameProgrammer

I think "assisted glide" or "extended glide" are good words for it. The car always coasts without using gas (unless your speed is really low) so zero-fuel glide isn't the best term IMO.

Since you can't accelerate in this mode, and you have to already be gliding (zero fuel consumption) in order to activate it, it's just a way of extending that glide or assisting it... so I like those terms.

The term 'Zero Fuel Glide' just means coasting, not necessarily coasting with assist. 'Assisted glide' or 'Extended Glide' is the same as 'Zero Fuel Glide with assist'.

[NASAgineer]

Originally Posted by ElanC

I agree.

Assisted glide. (AG)
Neutral (i.e. non-assist, non-regen) glide. (NG)
Regenerative glide. (RG)

should do it. The ZF doesn't tell us much.

Well, I was thinking of the complete newcomer who may not be aware that all gliding modes in the HCH-II consume zero fuel. That's based on many of the questions that have been asked here.