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Hi folks,
I have a question, mostly theoretical, about the advantage/disadvantage of using "full throttle" in a diesel engine
Firstly, let me say that I know that diesel engines aren't throttled the way gas engines are, even if the TDI has an intake "flap" that accomplishes roughly the same thing, but for different reasons.
Theoretically, a gas engine runs most efficiently at wide-open-throttle (WOT) because the engine doesn't have to suck air past a partially-closed throttle plate. Of course, you won't get better fuel economy by flooring it from stoplight to stoplight, but judicious use of full-throttle at low-mid rpm while accelerating to a cruising speed can be more efficient than forcing the engine to suck air past a throttle plate while accelerating slowly to speed.
This was pretty much my driving style (conditions permitting) in my previous 2000 Mazda Protege ES; let out the clutch sensibly, apply full throttle to about 3500 RPM (or more if needed/wanted), upshift, repeat. I got pretty good gas mileage, and arrived at cruising speed as briskly as 120 lb/ft of torque could deliver.
With 116 MORE lb/ft of torque than the Mazda, my 2011 TDI is hilariously fun to drive in the same manner. I'm getting EPA-estimate mileage, possibly because I DON'T do this nearly as often. But I wonder: is there some theoretical advantage to flooring it in a diesel? There's no throttle to restrict the intake when accelerating slowly, and the turbo (positive manifold pressure) complicates things anyway. So is it vastly more efficient to lug it up to speed slowly?
I have a question, mostly theoretical, about the advantage/disadvantage of using "full throttle" in a diesel engine
Firstly, let me say that I know that diesel engines aren't throttled the way gas engines are, even if the TDI has an intake "flap" that accomplishes roughly the same thing, but for different reasons.
Theoretically, a gas engine runs most efficiently at wide-open-throttle (WOT) because the engine doesn't have to suck air past a partially-closed throttle plate. Of course, you won't get better fuel economy by flooring it from stoplight to stoplight, but judicious use of full-throttle at low-mid rpm while accelerating to a cruising speed can be more efficient than forcing the engine to suck air past a throttle plate while accelerating slowly to speed.
This was pretty much my driving style (conditions permitting) in my previous 2000 Mazda Protege ES; let out the clutch sensibly, apply full throttle to about 3500 RPM (or more if needed/wanted), upshift, repeat. I got pretty good gas mileage, and arrived at cruising speed as briskly as 120 lb/ft of torque could deliver.
With 116 MORE lb/ft of torque than the Mazda, my 2011 TDI is hilariously fun to drive in the same manner. I'm getting EPA-estimate mileage, possibly because I DON'T do this nearly as often. But I wonder: is there some theoretical advantage to flooring it in a diesel? There's no throttle to restrict the intake when accelerating slowly, and the turbo (positive manifold pressure) complicates things anyway. So is it vastly more efficient to lug it up to speed slowly?
