30mpg results in roughly one gallon of gas used to travel 30 miles AND a gain of 25 miles of EV battery. Work the math and its 30miles of gas then 25miles of EV for a total of 55miles per the one gallon of gas. Which is better than the HV mode of 40-45mpg.
Altho it's possible what you're saying is true, I hope not because that would indicate some pretty bad engineering of this PHEV.
The Chevy Volt is engineered to operate with the best energy efficiency in both its EV mode and its gas-powered mode. In the gas-powered mode it's still using the gas motor mostly to power the electric generator, which bypasses the battery pack to directly power the electric motors. In other words, in gas-powered mode the Volt usually functions as a serial hybrid, rather than either charging the battery pack or directly engaging the gas engine into the powertrain. While it does sometimes directly engage the gas engine, when the battery pack is depleted and extra power is needed, that's pretty rare. And when the Volt does need to recharge the battery pack, to maintain a ~30% charge level, its efficiency is lower than when it's in gas-powered mode but not charging the pack.
What you seem to be suggesting, West1, is that the Clarity PHEV isn't engineered to run at its most efficient whenever the gas engine is running, and that in fact it's so inefficient that it's more efficient to use that to charge up the battery pack, despite the charging inefficiencies and the round-trip inefficiency in charging and discharging the battery pack.
I realize the Honda Clarity PHEV isn't the Chevy Volt, but I
hope Honda's engineering isn't that bad.
I would prefer to guess, West1, that your car isn't properly keeping gas-powered miles vs EV powered miles separate when reporting those, which would result in your figures being off.
Of course, my armchair-engineer assumptions here could be wrong.
Gas motors are most efficient when under a load or turned off. The charge mode allows the ICE to operate a near full energy efficient load. This propels the car and charges the battery. Once the battery is charged then the ICE can change to 100% efficient, which is when its turned off.
ICEVs work most efficiently when they are run with "wide open throttle" (WOT), which again is how the Volt's gas motor is designed to run. In a car with a carburetor, that means both the air intake and the fuel intake are wide open. But it seems rather improbable that a PHEV is engineered that way. (Well obviously not, since all modern gasmobiles use fuel injection rather than a carburetor.) Since we know it is possible to use the accelerator to speed up and slow down, the engine cannot be fed with wide-open fuel intake at all times. Logically, therefore, a PHEV running WOT must merely mean the air intake isn't being choked, but that the amount of fuel is still being regulated to control speed.
Again, I'm not seeing how the Clarity PHEV can be more fuel-efficient by using the gas engine to propel the car and charge the battery at the same time. From a thermodynamics analysis, that sounds impossible; it would be perpetual motion. That's not to say it actually is impossible in the real world, because no engine can possibly be built to attain the theoretical maximum efficiency, so the actual energy efficiency will depend on the engineering of that particular engine. But if it really is true that the Clarity PHEV's efficiency in normal gas-powered mode is so poor that it's actually improved by using the engine to simultaneously propel the car and charge the battery pack, then something appears to be very wrong with the engineering.
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