when the ICE is needed to absorb the regen energy
How can the running ICE absorb the regen energy?
Here is what I know:
1. All Honda i-MMD hybrids use the engine to turn the starter motor/generator to generate power
2. Honda's non-plug-in i-MMD hybrids use the starter motor/generator to turn a deadened ICE to use up excess regen power
3. The Clarity Plug-In Hybrid is an i-MMD hybrid
Clearly, using the ICE in its normal manner to generate additional power can't use up excess regen power.
That means that the Clarity PHEV is using the ICE in a different way to use up excess regen power.
Why would the Clarity require a different method of using up excess regen power? What makes the Clarity different from its non-plug-in siblings? The non-plug-in hybrids are the same as the Clarity, except for the size of their batteries. They, too, can travel under EV power, but just not as far. The bigger battery in the Clarity PHEV makes it heavier.
The greater momentum of the heavier Clarity PHEV produces more regen power to be dissipated. Honda had to find a way to use the same i-MMD system to dissipate more power than the deadened-ICE scheme that works for the non-plug-in hybrids.
My theory is that to use up the greater amount of regen energy produced by the heavier PHEV, the Clarity's starter motor/generator is actually
opposing the running ICE by trying to slow it down. I don't like the idea that the Clarity is burning gas to get rid of electrical power it cannot store, but I'm not imaginative enough to come up with any other explanation. Below is the part of my unverified
Clarity mode chart that illustrates this scheme.