Diesel differences

[RalphVa]

Wondering about your various experience/knowledge about the diesel state of the art. Just sat (actually laid) down to read a Mother Earth mag and saw a Mahindra ad. Says their diesels do not require a DPF. Yet Mahindra dropped their plans to bring over their diesel P/U, probably because of the high cost of doing lots of mileage to show emissions didn't go to pot.

I know Yanmars aren't the best: still shudder and shake on cold startup and require high idle speeds, supposedly for emissions. Yanmar technology seems to reside back in the 80s because our 1983 Benz more or less started the same in the cold and required almost identical glow plug timing. It would idle slower but didn't have to meet modern emission standards. Smoked a fair bit on heavy pull.

Isuzu starts and runs and sounds virtually like a gasoline engine except for that few second wait for the glow plugs built into its auto start. Don't know about its idle speed because it (as a generator driver) always runs at "fast idle", as JD calls those speeds. No smoke.

The VW TDI started, ran and performed like a fairly powerful (torquey) gasoline engine. It's DPF required about 5% fuel debit to start it off with a tad more fuel. Smelled afterwards, too, if you happened to stop during one or immediately right after. Absolutely no smoke, only that DPF burn stink.

Anyone else have some experience with others?

Ralph

 

[LouNY]

My little RAM 1500 with the 3.0 diesel starts quickly and smoothly,
idles around 700 rpm nice and steady. Pulls out real smooth and easy,
amazing amount of torque for a 3.0 liter (183 cu inch). Pulls the crew cab pickup
with nice quiet authority. It has even pulled a bit more then it's rated for with no fuss or muss.

Four tons of coal plus the trailer(4000+pounds)
Gets good mileage and just flat drives nice with over 420 foot pounds of torque at well under 2000 rpm (1600?).
When it does the DEF injection the fumes will make up tear up, the first diesel I can't back into a barn and unload while it's running.
All the newer tractors sound and feel better above 1200 rpm.

 

[jeff9366]

Wondering about your various experience/knowledge about the diesel state of the art. Just sat (actually laid) down to read a Mother Earth mag and saw a Mahindra ad. Says their diesels do not require a DPF.

Beginning about thirty-three horsepower most tractors have Diesel Particulate Filters.
A few Tier IV compliant tractors between 26 and 75 hp use DOC (Diesel Oxidation Catalyst) conversion. Mahindra is one. Mahindra has DOC of similar construction to DPF. Both DPF and DOC are honeycomb ceramic filters which supercede a muffler.
The DOC forces engine exhaust over a honeycomb ceramic structure coated with platinum, palladium, and rhodium. These catalysts oxidize carbon monoxide and hydrocarbons into carbon dioxide and water at hot exhaust temperature.

Mahindra has a DOC oven hot all the time, DPF tractors have an oven hot intermittently. There is no free lunch.

Diesel DOC emits dirty exhaust until hot, which would not be allowed in USA road vehicles. Or possibly Mahindra evaluated the $30 billion (and counting) costs incurred by VW for falsifying diesel emission tests and decided its truck technology is not clean enough for export.

Following summarizes cost to VW for exceeding diesel emission standards on their diesel engine cars. Not entirely germane, but somewhat so.

How much has Dieselgate cost Volkswagen?

Dec. 23, 2018 5:33 AM ET
|
About: Volkswagen AG ADR (VWAGY)|By: Yoel Minkoff, Seeking Alpha News Editor​

The cleanup of Volkswagen's (OTCPK:VWAGY) diesel cheating scandal will cost the automaker €5.5B in 2018, around €2B in 2019 and €1B in 2020, CFO Frank Witter told Boersen-Zeitung.

Since 2015, the German group has paid more than €27B to settle investor and consumer lawsuits, as well as regulatory fines and remedies tied to resolving excessive emissions levels in its diesel cars.

27,000,000,000 Euros = $30,760,000,000 $/US​

B....b....BILLIONS!​

 

[Rebeldad1]

I know Yanmars aren't the best: still shudder and shake on cold startup and require high idle speeds, supposedly for emissions. Yanmar technology seems to reside back in the 80s because our 1983 Benz more or less started the same in the cold
Yanmar= Japanese Benz = German

My Kioti starts about the same warm or cold. A little noisey but its noisey anyway

My older 1990s Mitsubishi started smothly in the cold just smoked a bit.

My older Long ( Romanian... Used by Count Dracula) had no glow plugs. Started just a bit slower in cold weather but idled fine

My New Holland excavator stutters some but smothes out quickly

 

[Rebeldad1]

My little RAM 1500 with the 3.0 diesel starts quickly and smoothly,
idles around 700 rpm nice and steady. Pulls out real smooth and easy,
amazing amount of torque for a 3.0 liter (183 cu inch). Pulls the crew cab pickup
with nice quiet authority. It has even pulled a bit more then it's rated for with no fuss or muss.
View attachment 637159
Four tons of coal plus the trailer(4000+pounds)
Gets good mileage and just flat drives nice with over 420 foot pounds of torque at well under 2000 rpm (1600?).
When it does the DEF injection the fumes will make up tear up, the first diesel I can't back into a barn and unload while it's running.
All the newer tractors sound and feel better above 1200 rpm.

I am sooo jealous... It would be my first choice for my next pickup.

Had a customer walk into my shop. Didnt even hear him drive up. Asked him if it really got 30 miles to the gallon. He said no.
Got 32mpg on his last road trip.

Funny thing is they dont advertise it anymore..

 

[LouNY]

I am sooo jealous... It would be my first choice for my next pickup.

Had a customer walk into my shop. Didnt even hear him drive up. Asked him if it really got 30 miles to the gallon. He said no.
Got 32mpg on his last road trip.

Funny thing is they dont advertise it anymore..

I don't get any where near 30, my rolling average has been 22-24 mpg in the winter,
unless we get into a sub zero spell then it will drop to 19-21 mpg.
Several reasons for that my driving is not open highway, it mostly country roads,
many times short trips and also I do idle it quite a bit.
Also I run heavy 10 ply LT tires, for the taller stronger sidewalls.
My summer driving usually runs right around 24 mpg with 26-28 mpg on trips.
I do like it I'm at 80,000 miles now and contemplating what I'll do in another year or two.

 

[RalphVa]

Does RAM still use Cummins diesels?

The VW TDI got 40 mpg over 70k miles. Our gas Mz3 is doing 36 over 30k miles. Correct the VW for Mz3 (same as Golf) weight: 44 mpg. That's pretty close to the 20% difference in diesel fuel value, but the TDI was turbo, Mz3 isn't but is 13.0 compression ratio. Just an aside, when talking about efficiency. I'm also interested in hearing about noise, etc. Sounds like the RAM 1500 is as equally quiet as the VW TDI.

Didn't know that Yanmar is essentially the same as German diesel. Makes sense: still back in the 1980s on tractors. Better on cars like VW TDI.

Let's hear from maybe the LS people that (I think) use Isuzu diesels.

Ralph

 

[LouNY]

The RAM 1500 is using a VM engine out of Europe,
the 3/4 and up are still Cummins diesel, rumor has it not much longer, have to wait and see.
The VM is so quite a person could almost mistake it for a gasser needing a valve adjustment.

As far as I'm concerned if the epa would back off a bit on the emission standards for the diesels they would be fantastic,
both performance and mileage. Instead of choking them so much, possibly their numbers make sense in an academic study
but they don't in the working world.

 

[ovrszd]

I don't get any where near 30, my rolling average has been 22-24 mpg in the winter,
unless we get into a sub zero spell then it will drop to 19-21 mpg.
Several reasons for that my driving is not open highway, it mostly country roads,
many times short trips and also I do idle it quite a bit.
Also I run heavy 10 ply LT tires, for the taller stronger sidewalls.
My summer driving usually runs right around 24 mpg with 26-28 mpg on trips.
I do like it I'm at 80,000 miles now and contemplating what I'll do in another year or two.

I believe your mpg claims. Well stated including the particulars that change mpg.

I don't believe off the cuff claims.

 

[ovrszd]

The RAM 1500 is using a VM engine out of Europe,
the 3/4 and up are still Cummins diesel, rumor has it not much longer, have to wait and see.
The VM is so quite a person could almost mistake it for a gasser needing a valve adjustment.

As far as I'm concerned if the epa would back off a bit on the emission standards for the diesels they would be fantastic,
both performance and mileage. Instead of choking them so much, possibly their numbers make sense in an academic study
but they don't in the working world.

Very well stated.

 

[grsthegreat]

My 1994 dodge 6.0 Cummins gets nearly 27mpg. You mean the smaller ones don’t get much bettet

 

[ovrszd]

My 1994 dodge 6.0 Cummins gets nearly 27mpg. You mean the smaller ones don’t get much bettet

I must have missed that one?? Didn't know Cummins made a 6.0 that was used in Dodge?

 

[ptsg]

VM are good engines. My old 1962 crawler had a 2 Cylinder VM aircooled engine. Land Rover uses VM engines on a bunch of their SUVs.

Here we have a:

2016 Mitsubishi Outlander 2.2L 150HP 4 cylinder turbo diesel, I can squeeze about 41 MPG out of it.
1994 Mitsubishi Pajero or Montero in the US with a 2.8L 125HP 4 cylinder turbo diesel, it does around 26 MPG or about 18 MPG towing about 5800 lbs (Tractor + Trailer + loader + mower).
2015 Renault Clio 1.5L 90HP 4 cylinder turbo diesel and it does about 65 MPG easily.

We had a 2009 VW Golf with the 1.6L 105HP. I can't remember the mileage but it was relatively bad for that car. I believe it was around 8 MPG. It was a pure mess with that DPF. Constantly giving problems and going into limp mode. We sold before all the VW scandal. Came to find out later, that that car was affected by that.

 

[Rebeldad1]

My 1994 dodge 6.0 Cummins gets nearly 27mpg. You mean the smaller ones don’t get much bettet

Lets see... you are in Idaho. I bet on a really quiet morning I can hear you start your truck here in Washington

 

[Industrial Toys]

I don't own one anymore, but think that Yanmar are one of the finest and smoothest engines you can buy. Has something changed?

Working on an Isuzu generator and for smoothness it will put all my Kubota powered generators and "Steiner" to shame.

Ooops, I lied. Still have a single cylinder air cooled Yanmar generator. Loud and horrible but ultra reliable.

 

[nova3930]

Beginning about thirty-three horsepower most tractors have Diesel Particulate Filters.
A few Tier IV compliant tractors between 26 and 75 hp use DOC (Diesel Oxidation Catalyst) conversion. Mahindra is one. Mahindra has DOC of similar construction to DPF. Both DPF and DOC are honeycomb ceramic filters which supercede a muffler.
The DOC forces engine exhaust over a honeycomb ceramic structure coated with platinum, palladium, and rhodium. These catalysts oxidize carbon monoxide and hydrocarbons into carbon dioxide and water at hot exhaust temperature.

Mahindra has a DOC oven hot all the time, DPF tractors have an oven hot intermittently. There is no free lunch.

Diesel DOC emits dirty exhaust until hot, which would not be allowed in USA road vehicles. Or possibly Mahindra evaluated the $30 billion (and counting) costs incurred by VW for falsifying diesel emission tests and decided its truck technology is not clean enough for export.

Trying to reconcile all this with what I know about diesel combustion and on road emissions from my various Cummins engines.

Tractor designs only utilizing a DPF, the engineers have probably decided to run relatively rich mixtures and/or are running LOTS of exhaust gas re-circulation (EGR). Those factors reduce combustion temperatures, reducing both NOX and CO at the expense of soot production, which they then clean up with the DPF.

A design utilizing a DOC without DPF is probably running a relatively lean mixture with less EGR, reducing soot and hydrocarbon emissions at the expense of CO and NOX, the CO being cleaned up by the DOC. In the case of the Mahindra with the common rail direct injection, they're probably using multiple injection events to control the combustion process and thus emissions. As I understand their system it's roughly equivalent to an on road truck of the early to mid 2000s vintange. The 03-07 5.9L cummins was a common rail direct injection system with EGR and DOC.

The thing I"m seeing that I guess allows for just using a DOC or DPF and not both is that Tier IV has a combined standard for NOX and hydrocarbons instead of being separate values as in on road requirements. It gives a lot more flexibility in meeting the standards.

I'd also hesitate in directly comparing a DOC with a DPF in their operation. A DOC operates effectively at 300*C+ when a typical diesel EGT is in the 700-800*C range, with bursts over 1000*C. A DOC will operate all day every day just by operating the engine, they don't require any extra fuel.

A DPF in comparison typically requires 900*C just to start consuming soot and requires much higher to consume soot faster than it's produced. That's why they have regen cycles at all. Diesel is injected late in the exhaust stroke where it combusts in the exhaust effectively, driving up the temp to burn the soot. Even then the things still plug up eventually.

Given my experience with on road engines, I'd take a common rail direct injection engine with a DOC over a DPF equipped vehicle all day every day. DPFs are the most problematic emissions component on modern on road diesels. On top of that I wouldn't want a DPF without SCR to allow combustion parameters that minimize soot production to start with.

That's just my general view of the various methods, I don't have any experience with the Mahindra system. All my experience comes from the on road world.

 

[nova3930]

I don't own one anymore, but think that Yanmar are one of the finest and smoothest engines you can buy. Has something changed?

Working on an Isuzu generator and for smoothness it will put all my Kubota powered generators and "Steiner" to shame.

Ooops, I lied. Still have a single cylinder air cooled Yanmar generator. Loud and horrible but ultra reliable.

I've got a Mustang 940 skid steer with a yanmar 4 cylinder diesel in it. 1989 model with who knows how many hours. Been rode hard and put up wet it's entire life. I haven't run it in a month and i know I can roll out there right now and have it fire right up on the first key turn. I would take a Yanmar over any other small diesel in existence.

 

[nova3930]

My 1994 dodge 6.0 Cummins gets nearly 27mpg. You mean the smaller ones don’t get much bettet

I must have missed that one?? Didn't know Cummins made a 6.0 that was used in Dodge?

He's talking about the Cummins 5.9L. Specifically the all mechanical 12V version of old. IMO the finest diesel engine ever produced by anybody anywhere. If not for emissions Dodge and half the commercial world would still be putting them in trucks.

 

[Industrial Toys]

I have under two hundred KMs on my 08, 6.6, but aside from glowplugs it has been flawless and I am very thankfull for that. It does like it's Diesel Fuel though.

 

[Molalla1]

Very well stated.

It sure was overzd . . . I have a 3500 '06 Ram with a Cummins . . . and just before the regulations really set in (probably why they went from the trusted 5.9 to the newer version) to make up for the power loss due to regulations.