Fuel efficiency vs Engine life

[pachhh34]

I was wondering according your experience do you think fuel efficiency and engine life go together or recently producers make more short-term machinery . Here in Bulgaria many people complain about the DPF and AdBlue when the engine goes on emergency mode. Overall, I have noticed in machines in general like cars that are produced for the leasing/warranty period therefore machines like the old CATs , Liebherr etc. wont be produced again as contemporary machines will have much shorter life.

So for example , would you buy a new machine with all the DPF , adblue and eco-friendly things or you'd rather buy a 10 yr old CAT or Liebherr with no emission standard equipment as I think the 05/06 generation is the last unruined ( in my opinion) machines.

 

[92U 3406]

There's 2 sides to this. Buy an older unit because of less emissions issues but then you have to deal with everything else. Fatigued steel, old hoses/seals, worn out pumps etc. Kind of seems like a no win situation either way unless you found something used that was looked after and not abused.

 

[Welder Dave]

Maybe an older Cat with a certified rebuild is a good way to go. There's too many variables comparing used to new. A good used machine without all the emissions crap could be made like new for a lot cheaper than a brand new machine with all the emissions crap.

 

[Birken Vogt]

A good used machine without all the emissions crap could be made like new for a lot cheaper than a brand new machine with all the emissions crap.

Most times that kind of sentiment is a pipe dream, the old machine will still try to nickel and dime you to death with the things you did not rebuild.

However, I can understand it being a valid calculation in this day and age. All this hyper complicated, untested, constantly changing, poorly documented, poorly supported engine and exhaust stuff gives us fits.

I feel like we are in the late 70s/early 80s smogger car time all over again.

Hopefully it will get better like it did in the 90s.

Then this current crop of machinery will be as worthless as a Colt Vista or a Chevy Cavalier.

 

[AdmissionPro123]

If say you drove 800cc, 1400cc and 1800cc engines in otherwise identical cars. All being driven over the same route, by the same drivers, over say a one-day period, you will be surprised to find that the1400cc car uses the least fuel. Many would say that the 800cc car ought to use the least fuel, however, they forget that that 800cc engine does not have the torque of the larger engines to tackle hilly Kampala and overtake swiftly on the highway, so shall often be in a lower gear, leading to increased consumption.

Additionally, other factors like how you drive, maintenance and traffic etc. It is because of this very reason that fuel consumption cannot be proportional to engine size in the real world. It is hard to take all sub factors into consideration, but yes, engine capacity is a factor for increased fuel consumption but the two are not directly proportional.

 

[check]

The principal beneficiaries of shorter machine life are the manufacturers and the bankers who collect interest on the loans. I would not expect this trend to change.

 

[Jim D]

Something that goes along with the new engine technology is newer style parts and construction, i.e. plastic body panels and roofs and plastic latches and switches. None of the plastic parts have the durability of the metal parts they replace, IMO. There are questions asked here on the forum about 50 and 60 year old machines, and usually there are answers that will keep them running. I doubt any machine made today will be usable 50 years from now.

Birken, those '75 to '85 smog cars were *real* dogs; I hope that the tier IV equipment today won't be the same story, all over again.

 

[Welder Dave]

How many owners would prefer if they could build a glider truck with a pre emissions engine without all the complicated electronics?

 

[spitzair]

How many owners would prefer if they could build a glider truck with a pre emissions engine without all the complicated electronics?

I know I sure would! Seems like they're nowhere near as easy to get one here in Canada as they are in the states though. Possible but not easy... At least from my research...

 

[old-iron-habit]

We are still going thru a learning curve on the diesels. It was the same when smog controls become standard on the cars. As much as I like the old stuff I can sure tell when I get behind a classic car on the freeway. They sure smell like raw gas and I can feel it in my eyes. I can't remember that from my youth. I guess we were just used to it. I think the manufacturers will sort it out but with all the electronics on the diesels. However I do not think they will be still running in 60 to 90 years like my old Caterpillars.

 

[John C.]

I'm not sure that anyone could make the claim that a more fuel efficient engine could or would run any longer than one that is less efficient. The life of an engine is more dependent on application, work load, maintenance and things like defects in materials and workmanship. I am seeing and hearing of people tracking engine life by gallons of fuel used instead of hours of operation. This seems to imply that a more fuel efficient engine would run more hours, I take it to mean a machine being run with a heavier load would not last as long. Say two engines driving 1000KW gensets are run at the same time and maintained the same way. One runs at 500KW while the other runs at 750KW. The logic says the engine running at 500KW will have one third longer life that the one running at 750KW. While logical I think I would have to see actual test results backing up that theory.

 

[check]

I'm not sure that anyone could make the claim that a more fuel efficient engine could or would run any longer than one that is less efficient. The life of an engine is more dependent on application, work load, maintenance and things like defects in materials and workmanship. I am seeing and hearing of people tracking engine life by gallons of fuel used instead of hours of operation. This seems to imply that a more fuel efficient engine would run more hours, I take it to mean a machine being run with a heavier load would not last as long. Say two engines driving 1000KW gensets are run at the same time and maintained the same way. One runs at 500KW while the other runs at 750KW. The logic says the engine running at 500KW will have one third longer life that the one running at 750KW. While logical I think I would have to see actual test results backing up that theory.

I remember back in the 80's we were told that engines lasted longer under full load than partial load. My experiences have shown the opposite. I worked on an offshore gas production platform off and on for 9 years and the generators were powered by Waukesha 1197 (cubic inch displacement) natural gas engines that were loaded very light, so light that they sputtered and nothing I did could make them sound right. Both of those engines already had over 60 thousand hours apiece when I quit and the rings, rod and main bearings never were touched.

 

[DMiller]

Manufacturers are stretching items very thin these days. They do not care for longevity, they care to sell parts and machines, more so whole machines. Engines are tweaked to about the limits now, some have double turbos, the advent of electronic injection has simplified changing fuel delivery to a given condition but as I see it the old machines tend to work long after the newer ones shoot craps in fields and require tech with PCs to recal or dig out the suspect components or conditions leading to a failure. Hell my old Allis loader uses 1/4 less fuel than a similar equipped OLD 931 Cat, it does not work as fast or as 'user friendly' but it works day in and out with only hard component failures doing it in.

 

[John C.]

check, I hear you on the natural gas engines but they don't run with near the long term problems of diesel. I've seen some propane fired Ford 300 inline six engines in old UPS vans with 300K miles and still running strong.

A diesel running at light load will put deposits on the rings and pistons and eventually they will start slobbering and making all kinds of blow by. That makes them leak and get even more messy. We went after operators leaving the engines run through lunch breaks. I've heard that an hour at low idle can be thought of as three hours at high speed full load. I've personally seen this in boat engines. Unless you put them on a dyno and load them hard for an hour or two after the rebuild, they will smoke a pretty shade of blue and stink for the life of that engine.

 

[Welder Dave]

It depends entirely on the engine model if idling makes them slobber or not. The shop that did my 3204 said don't let it idle for long periods but that some of the new cat engines could idle all day with no ill effects.

 

[check]

check, I hear you on the natural gas engines but they don't run with near the long term problems of diesel. I've seen some propane fired Ford 300 inline six engines in old UPS vans with 300K miles and still running strong.

A diesel running at light load will put deposits on the rings and pistons and eventually they will start slobbering and making all kinds of blow by. That makes them leak and get even more messy. We went after operators leaving the engines run through lunch breaks. I've heard that an hour at low idle can be thought of as three hours at high speed full load. I've personally seen this in boat engines. Unless you put them on a dyno and load them hard for an hour or two after the rebuild, they will smoke a pretty shade of blue and stink for the life of that engine.

Most older diesels seem to perform best at 60 to 95% load, in my opinion. It's true that natural gas engines last much longer than gasoline or diesel engines. I've heard of Cat 3406 derived gas compressor engines getting 90 thousand hours before overhaul.
I've also heard of old style Lister diesel engines getting 40 thousand hours before needing overhauls. I doubt any all Street managed corporation would want to sell engines that last that long. Sometimes they accidentally let one slip thru that lasts 15 thousand hours, but most are throw away at less than 10 thousand.
Regardless of operating conditions, the will of the manufacturer plays a huge role in how long any engine can last.

 

[funwithfuel]

Here's the rub as I have experienced it. In TierIII we had the introduction of high pressure rail fuel injection with either cooled EGR or external EGR of some sort. The High pressure rail intro ran at lower comp ratio, to minimize dependence on EGR . During this phase in , some manufacturers already began to see the effects, the metallurgy wasn't quite up to snuff. Some blocks began to erode at liner counter-bores, some heads failed at unusual locations.
TierIVi introduced regen or aftertreatment. More reliance on EGR almost exclusively cooled EGR to control NOx . Big bores used a more proven DOC/DPF regen while there was no standard for mid range engines between 6 & 9 liters . Tier IVf became less dependent on EGR but more on SCR. They found that by running hotter and harder , they by nature, produced less particulate matter(PM). This caused an increase in NOx production, but now with more accurately controlled EGR and more efficient cooling of the EGR added with the SCR introduction in the downstream flow, Nox was brought to near 0 levels. The higher combustion/exhaust temps while already reducing PM also contributed towards getting the DOC up to temp without the use of burners or additional ignition systems.
TierIVf was a huge step forward, TierIVi was a major set back but a stepping stone. The other thing that the mid range engines saw was the introduction of air throttle blades at the intake . This could help control EGR and cold weather heat up, by forcing the engine to work harder for that air.
Until the metallurgy catches up to the technology, we are gonna have problems with premature component failure. Add to that the higher pressures in the injection system ( injectors, pumps, regulators etc) with the ultra low sulfur fuel with no lubricity, and dependent on where you are and what kinda knucklehead purchases your fuel , you might be pushing corn oil through that 18,000 psi injector orifice. How long is that poor thing gonna last.
If they could maintain the operating systems , remove the emissions derate, they'd have some real powerhouse engines in much smaller packages with incredibly low fuel consumption.
Regen should not cause a derate. It has no damaging effect on the operating system. Just because a sensor is out of range, it's gonna shut down your whole production line. That's just there by gov't interference dictating that if any thing is tweaked or out of range or defeated in any way, it'll shut ya down. (not cool)
And lastly, how come only civilized countries have to put up with this. No China, No India, Some parts of Africa, Some parts of south America. Machines auctioned off in the states to out of country buyers can have emissions removed and software reprogrammed to run without, by the manufacturer!!! . They get the power, the fuel savings and the simplicity, we have to deal with BS.

Sorry for the long winded rant, but emissions are a bit of a sore subject with me. Machines today run so much cleaner and more efficient, I don't feel we need to keep going on the backs of those who work for a better tomorrow. We need to withdraw from the GHG treaties In My Opinion.