I live in MN so we have already had 1 or 2 winterish days. I notice that my regenerative breaking (the green bar on the instrument cluster) is not lighting up when I brake until the car is pretty warm. When it is in this "mode", it seems that it will charge itself a little off the gas engine. What I observe is that you get 1 or 2 bars of green even when the car should be using the electric motor to assist.

What I don't understand is why. Why would the generators need to be warm? I understand the battery might need to be warm to deliver current correctly, but does it need to be warm to accept current?

I'm wondering if this is a firmware bug or bad design.

My mileage is steadily falling from an all-time high of 45 down to 44.

It's definitely supposed to happen that way. No regen (or significantly decreased regen) when cold. Exactly why, I do not know.

A block heater will help should you chose to go that route. In addition to regen activating quicker, you will notice the cabin warming quicker, and less of a FE hit on warmup. Another benefit of a block heater include decreased engine wear.

I haven't gotten one yet, but I might do it just as yet.

Nope, it is not a bug or bad design.

As in most civilian applications the existing hybrid system on our Civics is designed according to a set of pre-determined tolerances purposely identified to maximize longevity and cost viability.

When cold, many moving parts wear more agressively especially if they are activated/triggered into motion at very fast rates. This is particularly true of the regen system on our cars. While this behavior can be offset with additional engineering and more entensive use of better materials it will likely place the car outside the cost range that many of us would be willing to pay for.


Cheers;

MSantos

By shifting into S(econd) you can force regenerative braking even when the car is cold, just shift it back into D(rive) when you have slowed/stopped and you are ready to go.

SolarDEK

I just installed my block heater, it defiantly helps the car warm up faster.
if you install one defiantly make sure you hook it up to a timer so it doesnt run all night.

Also the installation instructions are not for a hybrid, the hybrid coolant drain in on the back of the block on the passenger side.

you will need 2 gallons of honda coolant before you start, also you will need to open the bleeder valve while filling (this valve is next to the v-tec solenoids on the front of the engine).

I disagree about the installations not being for a Hybrid. I am having one installed tomorrow and have the instructions in PDF for a Hybrid so feel free to email me until this can get posted somewhere or I find where I found it. The biggest distinction to note is the part number (Hybrid block heater part # is 08T44-SVB-100 but the non-Hybrid block heater part # is 08T44-SNA-100).

--> Averaged 685 miles/week and 49.0 mpg in first year (35.7k miles from Aug 7, 2006 to Aug 7, 2007)

How then does the regeneration system warm up? If it does not turn when cold, where would any heat come from? Is it located somewhere near the combustion engine or exhaust? I figured it was near the brakes. I also figure, that brake heat dissipates quickly or you would end up boiling your brakeline fluid and have brake failure.

I have the thing installed, but i didnt have access to instructions for a hybrid. I should say, honda doesnt package the item with instructions for a hybrid.

The regenerative systems' main component is the motor rotor assembly. The motor assembly and its housing is actually bolted to the engine block inline with the ICE camshaft. And this is the main pathway for any heat transfer (cooling or warming) between the two. The motor stator position sensor is also one of those sensors that have a designated tolerance. Its acuracy is also affected by the lower temperatures so the IMA system will take that into account too.

The brakes contain sensors that also feed the IMA system and help it determine the adequate/safe operating conditions. For regeneration, the IMA motor is driven by the wheels and when appropriate it will function as a generator.

The other thing to keep in mind is that the battery pack has an ideal operating temperature range too. If it is either too cold or too hot the IMA system (BCM) will prevent current flow/exchange in order to not upset the cells chemistry and hence compromize its lifespan.

All-in-all it is a pretty balanced and neat system despite the technical compromises made during its design.


Cheers;

MSantos

It's not the regen system, it's the batteries. They like the same environmental conditions that we do. When they are at the right temp, they will start excepting a charge. No need to charge anything if there is nothing to accept the charge. Same thing happens when the batteries are fully charged. When they are, you will see there is no regen.

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