I agree.... During the DPF and regen debate the whole idea of RPM and traditional diesel efficiency somehow got overlooked. Customers were quick to accept running their new diesels wide open. Not sure why.....
It's gotten crazy, though. I've got a neighbor who bought a new 50 hp Kubota and leaves the throttle at near max all day long. Even when he walks away and it should be idling, he has it sitting there screaming at higher RPM than our old mechanically injected Kubota needs when working hard. It sounds like a race car coming down the straightaway. He says the regen requires it. But honestly I doubt he has ever tried it differently.
rScotty
Lots of guys have the wrong impression, though.
We don't need to run our engines wide open. This is basically a myth. As far as I can tell it originated due to many dealers recommending not to run full load at
lower rpm, due to exhaust SOOT (particulate emissions). Running at conditions that produce more soot will more quickly clog the DPF, leading to more frequent regenerations needed to clear it back out. But there was never really data behind that suggestion, just a general sense that at higher rpm, you probably don't need 100% load as often, and thus should produce less overall soot. The other aspect of it is that at higher rpm, you have more heat in the exhaust. The DPF can regenerate
passively, if it has enough ambient heat coming down the exhaust pipe. At lower rpm, you typically don't.
But you know what? It doesn't even matter. I run my daedong diesel engine at whatever conditions I want, just like I would any older tractor. It doesn't matter. I get DPF regens every 40-50 hours, looks like (only had two since I bought it).
My kioti has a "linked pedal" feature where it automatically revs up when you hit the hydro forward pedal, to add power when you need it - kinda like driving a car with an auto trans. This is pretty fancy and nice, but does result in you rev'ing the engine up and down a whole lot more. So, I must admit that I did stop using it, since it would logically lead to more soot production (think of the quick black cloud whenever you rev up most diesels). But ~1800 rpm is nice and quiet, and still has more than enough power and speed (in medium range) to do most loader tasks for me. Plus it is every bit as fuel efficient as my prior 3-cyl, 30 HP mitsubishi diesel engine. Well under a gallon per hour for general light duty work.