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JSH · 01-10-2024, 03:03 PM

This is more like Dieselgate 5.0 – at least a half dozen companies have been caught cheating on diesel emission since VW got busted. From the top of my head in the USA it has been Ram, Jeep and Mercedes

We will find out how Cummins cheated when the consent decree is published. All we know right now is that Cummins has been caught using multiple undisclosed AECDs. An AECD is generally an alternative map. They are legal if disclosed to EPA and CARB and approved by those regulatory bodies. They are intended to allow increased emission when there has been some sort of failure to protect the engine from damage. For example if an O2 sensor fails and the ECM cannot continually adjust mapping based on O2 sensor data the vehicle will revert to a fixed map and light the check engine light.

However, these AECDs were not disclosed so they are assumed to be a defeat device intended to allow increased emissions outside the conditions of a test lab. Multiple companies have been caught using alternative maps when the vehicle knows it is not on a test dyno and that cheating goes back as far as EFI. Some methods used to know when the vehicle is not on a dyno: Wheel positions (VW), Temperature (FCA), Length of steady throttle (Ford), Time (CAT, Cummins, Detroit Diesel, Mack, Navistar, Volvo)

Removing emission equipment only increases fuel economy at the expense of local emissions. When FCA got caught cheating on the 3.0L EcoDiesel their defeat device increased NOx 65 times more than the allowed regulatory standard. Good fuel economy and clean emission are not mutually exclusive. The HD diesel industry has increased fuel economy by about 1/3 since aftertreatments became mandatory back in 2010. A fully loaded Class 8 pulling a box trailer can do 10 mpg today in real world conditions.

Diesel aftertreatments are fantastic technology – they allow us to start up and run vehicle inside a factory without exhaust extraction (similar to propane vehicles). They allow diesels to meet the same emission regulations as gasoline vehicles – which helps clean up our urban air quality. They are not cheap but they work.

Plenty of failures are due to user error or driving conditions that do not match a diesel. Idling is the death of particulate filters – the HD market found that out pretty quick and now they use APUs for hotel loads instead of idling the main engine. However, the consumer market has been slower to catch on. You still see people that live by the old rule that you should never shut off a diesel. I see people STILL leaving their 2023 diesel trucks running while they go into a store. That is a recipe for disaster. It not only shorts the DPF life but it also reduces fuel economy because regens use fuel.

Same with using the wrong oil. Maybe someone has used the same 15W-45 oil for decades with no problem but if you don’t run a low-ash oil in a modern diesel the ash left over when that oil burns will permanently plug the DPF.

And then there is poor quality DEF or leaving a diesel sit with DEF in the tank. This is what killed the DEF header / sending unit in my Express 4500 and cost me about $2,000. The ambulance I bought had been sitting for more than a year. DEF is mostly water and water evaporates out. That concentrates the DEF and makes it more corrosive – eating the resins used to pot and seal sensors. DEF only lasts 1 year kept out of light and between 10 and 90 degrees F. It will last 2 years if stored at a climate controlled 75 degrees.

Really today economics do not favor diesel engines outside of a few applications. They cost thousand more to buy, the fuel now costs 25% more which negates the fuel savings. And when anything in the emission system fails they go into limp mode after about 500 miles. You can run a gas engine with the check engine light on for years. (Of course there is the question of whether gas engines should also go into limp mode if their emission systems are not working) There are limited use cases today where a diesel makes sense. Mainly hauling loads at highway speeds or running stationary equipment at high load. Outside of that – gasoline is likely the more economical choice.

01-10-2024, 03:03 PM	#10 (permalink)
JSH AKA - Jason Join Date: May 2009 Location: PDX Posts: 3,599 Adventure Seeker - '04 Chevy Astro - Campervan 90 day: 17.3 mpg (US) Thanks: 325 Thanked 2,146 Times in 1,453 Posts	This is more like Dieselgate 5.0 – at least a half dozen companies have been caught cheating on diesel emission since VW got busted. From the top of my head in the USA it has been Ram, Jeep and Mercedes We will find out how Cummins cheated when the consent decree is published. All we know right now is that Cummins has been caught using multiple undisclosed AECDs. An AECD is generally an alternative map. They are legal if disclosed to EPA and CARB and approved by those regulatory bodies. They are intended to allow increased emission when there has been some sort of failure to protect the engine from damage. For example if an O2 sensor fails and the ECM cannot continually adjust mapping based on O2 sensor data the vehicle will revert to a fixed map and light the check engine light. However, these AECDs were not disclosed so they are assumed to be a defeat device intended to allow increased emissions outside the conditions of a test lab. Multiple companies have been caught using alternative maps when the vehicle knows it is not on a test dyno and that cheating goes back as far as EFI. Some methods used to know when the vehicle is not on a dyno: Wheel positions (VW), Temperature (FCA), Length of steady throttle (Ford), Time (CAT, Cummins, Detroit Diesel, Mack, Navistar, Volvo) Removing emission equipment only increases fuel economy at the expense of local emissions. When FCA got caught cheating on the 3.0L EcoDiesel their defeat device increased NOx 65 times more than the allowed regulatory standard. Good fuel economy and clean emission are not mutually exclusive. The HD diesel industry has increased fuel economy by about 1/3 since aftertreatments became mandatory back in 2010. A fully loaded Class 8 pulling a box trailer can do 10 mpg today in real world conditions. Diesel aftertreatments are fantastic technology – they allow us to start up and run vehicle inside a factory without exhaust extraction (similar to propane vehicles). They allow diesels to meet the same emission regulations as gasoline vehicles – which helps clean up our urban air quality. They are not cheap but they work. Plenty of failures are due to user error or driving conditions that do not match a diesel. Idling is the death of particulate filters – the HD market found that out pretty quick and now they use APUs for hotel loads instead of idling the main engine. However, the consumer market has been slower to catch on. You still see people that live by the old rule that you should never shut off a diesel. I see people STILL leaving their 2023 diesel trucks running while they go into a store. That is a recipe for disaster. It not only shorts the DPF life but it also reduces fuel economy because regens use fuel. Same with using the wrong oil. Maybe someone has used the same 15W-45 oil for decades with no problem but if you don’t run a low-ash oil in a modern diesel the ash left over when that oil burns will permanently plug the DPF. And then there is poor quality DEF or leaving a diesel sit with DEF in the tank. This is what killed the DEF header / sending unit in my Express 4500 and cost me about $2,000. The ambulance I bought had been sitting for more than a year. DEF is mostly water and water evaporates out. That concentrates the DEF and makes it more corrosive – eating the resins used to pot and seal sensors. DEF only lasts 1 year kept out of light and between 10 and 90 degrees F. It will last 2 years if stored at a climate controlled 75 degrees. Really today economics do not favor diesel engines outside of a few applications. They cost thousand more to buy, the fuel now costs 25% more which negates the fuel savings. And when anything in the emission system fails they go into limp mode after about 500 miles. You can run a gas engine with the check engine light on for years. (Of course there is the question of whether gas engines should also go into limp mode if their emission systems are not working) There are limited use cases today where a diesel makes sense. Mainly hauling loads at highway speeds or running stationary equipment at high load. Outside of that – gasoline is likely the more economical choice.