Exactly, and with the crazy emission systems due to increased regulations it lowered power and efficiency, so I guess cheating made sense to them. Bottom line they got bagged and will now pay the piper.
Cummins to recall 600,000 trucks for emissions cheating
- Thread starter AZjeff
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We have certainly entered the region of diminishing marginal returns on emissions, at least any meaningful, physical or financial returns...the political returns keep coming though.
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Personally I'd be pretty pissed if I paid the enormous price tag of these diesel pickups only to have it recalled a few years down the road to make it have less power, be less fuel efficient, and also take a potential reliability hit. The customer always loses.
Flawed epa logic.
I get that it's because of NOx, but I think we know what the end result will be. We either won't be able to buy diesels or it won't be attractive to do so especially since tuners are getting punished now.
Combustion temps are lower. People think "oh, I gained 2 mpgs which offsets the extra emissions". That's not the case.
Unfortunately gasoline compression ignition has not made significant advances.
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Usually the most significant looses are to the customer. Epa, cummins, and stellantis will just finger point at each other, and the media will run with whichever storyline gets the most clicks. Then average folks will take these and label it as "facts".
I do understand why that's the case. It's still just weird to think that a more complete or efficient burn is worse for emissions.
More efficient burn is hotter burn. More heat degrades the nitrogen in the air, turning it into nox.
I wonder if instead of restricting air to lower combustion temps they could inject less fuel, so there's enough extra air to cool combustion temps down.
Or use water injection but most people won't take care of a water injection system
Injecting less fuel would also be a leaner burn which by nature gets hotter. I bet that's why they restrict air instead of fuel.
HEAT is the killer. More efficient is not 100 percent efficient. Diesel combustion has a theoretical max of 55-60% efficiency. Some oxygen always survives the combustion process and the rate at which this oxygen binds with nitrogen accelerates as temps increase. NOX production has always been the boogie-man for "lean burn" because it required special TWC to scrub the additional NOX. TGDI engines will run rich to help reduce NOX. Diesel obviously can't do that because of soot production so it uses EGR.
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A high Air/Fuel ratio means more heat. Less fuel just makes combustion leaner and therefore hotter. A neat trick would be variable displacement but I don't know if that has or can be reliably implemented with diesel. .
I know leaner=hotter, but there comes a point where there's not enough fuel to make a lot of heat. At that point the engine probably won't make enough power to run though.
The real reason is verboten, so just live with it.
Not in a Diesel, They're throttled by fuel & the leaner they are.....The cooler the combustion temperatures are.
A throttle blade is only used to force the engine to ingest more inert exhaust gases than it could naturally with a EGR valve by it's self.
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