OK after reading a little more about this DCD system, I think I understand a little more about why it could be somewhat efficient...
Since English is apparently Heihetech's second language (I am guessing?) the way he uses words is a little different than what most of us are used to, but since I only speak one language I can't fault him for these differences.
If I am understanding this correctly, these are the 2 things going on:
- First it's simply interrupting the signal to each injector in a random pattern, based on load or throttle position or whatever data source it uses. The reduction in fuel consumption "at face value" seems self explanatory there, if it doesn't introduce a pumping inefficiency.
- Second, because the cooler air drawn into each (momentarily inactive) cylinder during the intake cycle is heated both by compression and by the neighboring active cylinders, it acts as a weak stirling engine so although there are pumping losses from drawing air in and out past the valves, the net energy lost into inactive cylinders is potentially less than you'd expect
So, up to a certain point if you randomly disable injectors, say, 20% and then alter the o2 sensor feedback by the same 20%, and you lose 10% net efficiency into pumping air past the valves on dead cylinders, you still end up with a net 10% less fuel entering the engine - and because you're
drawing work out of waste heat this also slightly relieves your cooling system because less fuel burned always means less gross heat generated (these numbers are just arbitrary examples for the purpose of discussion)
Am I understanding this correctly? Or am I way off?
