Quote:
Originally Posted by Heihetech
Shovel,
Thanks for the correct guess, and fully understand DCD into the inner core.
DCD does Has "AIR-HYBRID" Function to Recover Residual Heat in the Cylinder.
I name such function as "AIR-HYBRID", which is a special function of DCD ----
Implementation of “Air-Hybrid” with cylinder residual heat recovery.
Under the control of the DCD product, cold inlet air will become the
working fluid of the engine under DCD control, absorbing residual heat inside
the cylinders, thus expanding and contributing positive engine work, at least
some less negative work from compression that causes thermodynamic loss
(Note that traditional "air spring" is never an idea one.). Such an innovative
“Air-Hybrid” mechanism would not only increase engine efficiency, recover
residual heat and obtain extra power, but also could implement forced internal
air-cooling result inside the cylinders, avoiding engine knocking and partial
overheating, and reducing the heat loss from the radiator.
In just one word, the overall result of DCD is quite positive and effective.
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If you're not deactivating at least the intake valve, you're not going to see much of an increase in fuel economy.
First of all, traditional cylinder deactivation schemes do contribute to overall engine efficiency in that the firing cylinders in a variable displacement engine have higher peak compression pressures than with a similar engine with no variable displacement scheme in place. This is in contrast to this item:
link
Second, pumping losses are less with a traditional cylinder deactivation scheme than with this DCD gimmick because the deactivated cylinders do not pump air. Therefore, they, unlike DCD, do not contribute to forming economy-robbing engine vacuum, nor do they contribute to economy-robbing exhaust flow.
Third, since there is no airflow through the deactivated cylinders in a traditional cylinder deactivation scheme, the deactivated cylinders will approach average coolant temperature. This is in contrast to this DCD gimmick, where airflow through deactivated cylinders will actually cool the cylinders below average coolant temperature, and will cause increased wear of piston rings. This is the so-called "thermodynamic expansion" mentioned with DCD.