Quote:
Originally Posted by P-hack
But you are implying that it reduces the number of variables, when you have a reactor to control now, with varying amounts of hydrogen/etc generated per stroke.
I'm not sure if HCCI v DI v ? is the ultimate arrangement, but, like fuel injection (vs feedback carbs), we need to get precise control of the air charge and take it from there.
|
And you are correct in that it would be another layer of complexity having a POx generator feeding an HCCI capable engine. And, it is not as "precise" in it's production as we would like. Intake air heating and intake boosting are also "imprecise" to the needs for the very narrow value of variables to induce the combustion event. This is why some researchers simply track the airflow temperature and pressure and inject a varying mix of gasoline and diesel since those can be precise in delivery. Using Direct injection is an advantage adding that much more precision in comparison to port injection and I am certain that it will be tried with HCCI, if not now, soon.
However, the original post and links was for a device that simply feeds a common engine with a reactive diluent. The device is more than precise enough, and rapid enough to provide the needs of an engine this way. It looks like it is capable of using the EGR from off idle on up to full power reducing engine out emissions considerably and saving on cost and complexity in that sense. They claim a peak thermal efficiency of 42% - right in the ballpark of current diesel tech. However, the emissions advantage of the D-EGR engine means only a TWC ( three way catalyst ) is needed unlike a "clean" diesel's need for a DOC ( direct oxidation catalyst ), diesel particulate filter (DPF) and NOx trap with urea dosing.
A friend of mine bought a Chevy Volt and likes all aspects of it except for it's pedestrian mileage return on the freeway. HCCI would be ideal in this application since the engine dynamics would be near constant. But, a solution such as the D-EGR engine, could, for the time being, help narrow the efficiency gap between gasoline SI engines and modern diesels without the cost and complexity of the diesel. This will allow serial hybrids to improve on the highway portion of their use.