Diesel differences

[troverman]

Thanks for mostly repeating me. A DPF without SCR is pretty much the worst setup you can get. That's basically an on-road setup from 2008-2012 which are known to burn massive amounts of fuel and have bad reliability problems with the DPF. Comparatively common rail with EGR and DOC is an early 2000s setup which are very robust. If you can meet the emissions requirements without the DPF, there's no reason to have it, whether it's overall cleaner or not, especially without SCR.

Well, it certainly is true the Ford 6.4L had this type of system and had a lot of problems. Possibly others. It was still the early days of DPFs. Yet today, most non-road diesel under 75HP is operating with a DPF and EGR and no SCR. I've had two Kubotas including my current one; there is no issue. Fuel consumption is just fine.

Bosch is a hardware provider. They're not responsible for implementation and programming.

Not true, Bosch knew exactly what was going on and allowed it. This is well documented.

Primarily caused by Ford and GM not properly specing the vehicle fuel filtration system to meet the pump requirements. Other applications of the CP4 with proper filtration work just fine. Basically if any pump fails you're going to have massive fuel system damage. nature of the beast.

I can't speak for GM but all Ford diesels with the CP4 have always used two fuel filters, a frame mount and engine mount, with a water drain on the frame mount. I've often heard your argument made regarding improper filtration, but it simply isn't true. Having owned both, there's not much difference other than the ones in the Ford are a whole lot easier to access.

Wasn't aware of the Duramax swap, but that still leaves a large portion of diesel applications that use it, including a big chunk of European manufacturers. I knew Cummins had swapped to the CP4 for a variety of reasons, again with no known problems, probably because the Ram setup has dual fuel filters, one rear frame mounted with water separator and one front engine mounted.

VW TDI engines have also had fuel pump failures. They use a single piston version of the CP4. I don't think the CP4 is a wholly bad pump, but there is no doubt it has a poor reliability record when contrasted to the previous CP3. RAM will be equally vulnerable to failures. If you pumped a bad load of diesel with a high water content, eventually the separator fills and the water moves forward to the pump. By the time the WIF light comes on, the event is recorded in the PCM and warranty can be denied on that basis alone.

If Kubota uses it, good for them, they're ahead of the curve, although I'm unaware of any particular reason you have to have it. I never said it was anything special, just that it's a preferred engineering solution to an emissions requirement over other fixes. If your controls are programmed correctly you can meet emissions without the problematic DPF. Multiple injection events give multiple burn initial conditions, controlling both mixture and combustion temperature to reduce both soot and NOX. Looking at some of the designs, it appears as if DPF is being used as a bandaid to avoid changing the engine substantially.

There are novel injector designs but none are currently in production. With ever increasing emissions requirements, some sort of a filter is going to be necessary, even with extremely clean combustion. It is still combustion, after all.

 

[nova3930]

Well, it certainly is true the Ford 6.4L had this type of system and had a lot of problems. Possibly others. It was still the early days of DPFs. Yet today, most non-road diesel under 75HP is operating with a DPF and EGR and no SCR. I've had two Kubotas including my current one; there is no issue. Fuel consumption is just fine.

It really wasn't the early days. The emissions didn't change such that they were necessary in on road vehicles till 2007, but DPFs have been around since the 80s. The early Rams had their issues similar to, but not as severe as the Ford. IIRC Duramax did as well. DPF issues weren't truly abated until the the introduction of SCR allowing leaner, hotter burn to reduce soot while allowing NOX cleanup on the back end. Even then, it's a maintenance issue that has to be addressed. Just look at the preponderance of DPF cleaning and maintenance services for OTR trucks.

In my professional opinion as an engineer, DPF without SCR is a poor design. To intentionally feed high soot loads to a filter is asking for issues, especially when the filter isn't strictly necessary and introduces a lot of added complexity. DPF and SCR are complimentary systems that allow for optimal engine setup within emissions requirements.

Not true, Bosch knew exactly what was going on and allowed it. This is well documented.

Regardless of whether they knew or not, they're not responsible for what VW did. It's not my responsibility if I sell you a knife and you go stab someone. Every product out there can be misused and abused.

I can't speak for GM but all Ford diesels with the CP4 have always used two fuel filters, a frame mount and engine mount, with a water drain on the frame mount. I've often heard your argument made regarding improper filtration, but it simply isn't true. Having owned both, there's not much difference other than the ones in the Ford are a whole lot easier to access.

VW TDI engines have also had fuel pump failures. They use a single piston version of the CP4. I don't think the CP4 is a wholly bad pump, but there is no doubt it has a poor reliability record when contrasted to the previous CP3. RAM will be equally vulnerable to failures. If you pumped a bad load of diesel with a high water content, eventually the separator fills and the water moves forward to the pump. By the time the WIF light comes on, the event is recorded in the PCM and warranty can be denied on that basis alone.

I'd say it's factually accurate. My understanding is that water filtration is where things don't meet spec. If one bad tank of fuel overloads your water retention capacity, you don't have enough filtration capacity. On the turbines I supported until recently, our filters were speced to contain contamination from fuel that was 3 sigmas to the dirty side for double the maintenance interval, all to protect the remainder of the fuel system.

The fact that Ford and GM were jerks about the warranty doesn't reflect on the pump.

There are novel injector designs but none are currently in production. With ever increasing emissions requirements, some sort of a filter is going to be necessary, even with extremely clean combustion. It is still combustion, after all.

I've stated several times I think that's true. In the future they will all be common rail with EGR, DOC, DPF and SCR. The EPA is determined to get near zero NOX emissions and aren't going to relax PM regulations to get it. My point was you can meet the current emissions requirements with the correct programming though. If you couldn't, then they'd all need a DPF, but they don't.....

 

[finn1]

Bosch owns the core operating system and algorithms in their Ecuador. Engine manufacturers can add strategies, but Bosch approves and implements those strategies.

The illegal strategies were in the core Bosch programs, and were used by more than just VW.

The German government recently raided Mercedes, among others.

It’s not over.

DPF without scr works ok, depending on which NOx level your product operates in.

Note that there is a preponderance of off highway equipment rated right at 74 hp with DPF only.

The next increment is at around 90-99 hp, and they have both DPF and SCR....the rules change at 75hp.

DPF was around in the 80s only in very limited applications, mostly pilot and proof of concept programs.

Corning and the other substrate manufacturers weren’t ready until after 2007, and the launches were hellacious.

 

[sd455dan]

That's the point of the DPF - to remove soot. Keep in mind, as I mentioned, Kubota (and Deere) are using both DOC+DPF. The DOC handles catalyzing certain pollutants while cooled EGR reduces NOx and the DPF nearly eliminates soot. Total measurable emissions will be less on a DOC+DPF system.

Frankly, the Bosch fuel system being the best of the best is debatable. Bosch knowingly allowed their ECU's to have a cheat mode on the VW TDI engines. The Bosch CP4 high pressure fuel pump used on LML Duramax engines and 6.7L Ford Powerstroke engines is considered one of the least reliable fuel pumps on the market, causing catastrophic damage to the entire fuel system upon failure. In fact, to update you, Duramax engines no longer use Bosch at all, as of 2017. They have switched to a Japanese made Denso fuel system. Conversely, Cummins has an all-new 6.7L diesel for 2019 which has moved to the Bosch CP4 pump, same as Ford. As of 2018, they used the much more reliable CP3 system, which flowed more fuel volume but at less fuel pressure than a CP4.

Any of the common rail systems are "precisely controlling the combustion process." Mahindra has nothing special here...if you have an engine that is over 26HP, you must have electronically controlled common rail injection. Everything does now.

Any of the common rail systems are "precisely controlling the combustion process."


Mahindra has nothing special here...


Yeah not that new Cummins has used it in the Dodge trucks for over 16 years

Common rail on the early Rams is so common the price of a failed Bosch injector which sold for around $450 in 03 can now be purchased for about $190



if you have an engine that is over 26HP, you must have electronically controlled common rail injection.

Everything does now.[/QUOTE]


Well Not quite...

Branson tractors are the 1? exception

Kukje diesels still utilize in line pumps and mechanical injectors, all the way up to up the 55 hp tractors

That should also include TYM tractors with Kukje diesels

 

[finn1]

At one time, there were emissions waivers for low volume producers. Not sure if that still exists, though.

There was also a fleet averaging and a banking and trading provision in place so not all product had to be in strict compliance with the tailpipe emission regulations.

Point is, just because TYM is peddling product with old pln technology instead of common rail doesn’t mean they are meeting the standards.

They may be buying their war around the standards, legally, until their technology is up to snuff.

 

[ptsg]

Well Not quite...

Branson tractors are the 1? exception

Kukje diesels still utilize in line pumps and mechanical injectors, all the way up to up the 55 hp tractors

That should also include TYM tractors with Kukje diesels

Make it: up to 75HP.

The 7845 also uses inline pump and mechanical injectors on the D3400 engine. It does have a DOC+DPF though, while the rest uses DOC.

 

[murphy1244]

Very interesting thread. I learned much! Thanks to all.

 

[ovrszd]

Very interesting thread. I learned much! Thank to all.

Me too Murph. Although sometimes it felt like drinking water from a 5 gallon bucket.

 

[finn1]

Make it: up to 75HP.

The 7845 also uses inline pump and mechanical injectors on the D3400 engine. It does have a DOC+DPF though, while the rest uses DOC.

Also remember that a pln system will have none of the performance and ergonomic advantages that a modern common rail system with pilot injection and flexible timing capabilities can offer. Noise, fuel economy, and even cold starting and diagnostics capability all suffer with a pln system.

Pretty much like owning a car with a carburetor and points ignition system. It may work, but it痴 pretty obsolete in today痴 world, from an engine and controls standpoint. Not easy to optimize, with a lot of performance and ergonomics compromises.

 

[ptsg]

Also remember that a pln system will have none of the performance and ergonomic advantages that a modern common rail system with pilot injection and flexible timing capabilities can offer. Noise, fuel economy, and even cold starting and diagnostics capability all suffer with a pln system.

Pretty much like owning a car with a carburetor and points ignition system. It may work, but itç—´ pretty obsolete in todayç—´ world, from an engine and controls standpoint. Not easy to optimize, with a lot of performance and ergonomics compromises.

After all, it's just a tractor. No need to get fancy, just to be reliable and get the job done. Which a pln system will do just fine as it doesn't requires a bunch of sensitive electronics to run it.