In light of the discovery of what Volkswagen has done to Diesel cars, is anyone, anywhere, anyplace really meeting Diesel emission standards?
This may be semi-OT, but Diesel emission regs are Coming Real Soon to a Railroad Near You. Of the many folks around here who are technically savy, what exactly did VW do?
When I was an engineer at a Major North American Car Company, my supervisor who was expert in all things engines-and-emissions spoke of something called a "hay sniffer." Specifically, the car met emissions when it was driven according to the EPA Federal Test Procedure, but when the software detected that you were cruising down the open road at speeds in excess of that protocol, the software "sniffed the smell of hay" that you were far beyond the city limits where smog was a problem, and it reverted the engine to a more fuel-efficient operation.
Is this what VW is accused of doing, implementing a hay sniffer? The media coverage seem to suggest that they are engaged in a more direct form of cheating, that is, they can detect when your car is plugged into a vehicle inspection test through the OBD-II port (that plug right under your steering wheel).
But if that (in my view more sinister) thing is what they did, how did they pass the emissions test in Ann Arbor, MI for certifying the vehicle for sale? For that test, the only thing different about the car is that the car sits on rollers instead of drives on a road, a hose is connected to the exhaust pipe to measure what comes out, and a professional driver carefully follows the pattern of speed-ups and slow-downs making up the test -- I didn't think any data was taken from the engine-control computer as that kind of test is used at smog-check stations in counties required to have them as a simpler expedient to the full-blown EPA test.
On the other hand, if they detected the mode of operation -- city traffic, urban freeway, 70 MPH cruising on the open road -- what specifically is wrong with adjusting the emission controls to meet the EPA test but give good performance outside of those conditions? There are a lot of cars that are "tuned" to give good EPA gas mileage numbers (piggybacked on the emissions test) but are gas guzzlers in regular use as a result of the type of "optimizations."
Well, it is wrong if they violated specific rules that the smog control software is supposed to adhere to, but if what they were doing was optimizing the car for different modes of operation, that is how modern smog controls work?
Is this story reported accurately, or is there more to it?
If GM "killed the electric car", what am I doing standing next to an EV-1, a half a block from the WSOR tracks?
^the litigation has just begun!
Never too old to have a happy childhood!
Yes, that offers insight into the legal end of things.
Anyone clued into the technical side of this because I think it is going (woosh!) over the tops of heads in the regular media?
This is sure going over my head, but I do recall when emissions testing began in the '70s mechanics had to mess around with my Volkswagen "Bug" to get it to pass. Trouble was, the car ran lousy afterward. So, after getting home from the inspection station I had to put it back where it was supposed to be so the car would run right. Easy to do on a "Bug" back in those "points, coils, rotor and distributor" days.
There are a lot of cars that are "tuned" to give good EPA gas mileage numbers (piggybacked on the emissions test) but are gas guzzlers in regular use as a result of the type of "optimizations."
This is exactly what I am talking about.
A Corvette is a somewhat lighter weight car (beefy tires and frame but compact size and plastic body) with a very powerful engine. You have to drive it with a light throttle to meet the EPA Federal Test Procedure "drive cycle" that assumes Granny is driving a Nash Rambler. If you drive it more robustly as is the habit of most Corvette owners, this level of acceleration is well outside the Federal drive cycle so the engine and transmission settings don't have to be tuned for frumpy gear shifts/high gas mileage when driven that way.
But there is a fine line between optimizing the emissions and fuel economy for a specific drive cycle, programming the software to specifically recognize being outside the drive cycle and retuning the engine for better performance/worse smog under those conditions (the "hay sniffer", which may have been "pushing the rules"), and an outright "defeat device" that switches modes when it detects the car is being tested at a smog station with a hookup to the OBD-II port (does the smog tester send commands through the OBD-II port to your engine computer, or does it merely read values, and if it is reading values, is there some "cheat" in the software.
I am trying to figure out whether VW is accused of aggressively tuning their Diesel cars, of implementing a "hay sniffer" subroutine in the engine control software that is forbidden by EPA rules, or a more blatant cheat.
As BaltACD offered so glibly, yes, there will be litigation to answer that question, but us tech geeks want to get to the bottom of this . . . now! Do the people in the media even understand the difference between the Corvette tuned for light-throttle operation to meet EPA that owners never use and more blatant detection-of-being-under-test?
How would this detection-of-being-under-test work during emissions qualification on the test stand in Ann Arbor? If the car were driven according to the Granny-in-her-Rambler speeds as the FTP (Federal Test Procedure) on real streets, would it not turn in the same fuel mileage and performance and emissions? Or do they detect the plug connection under the dash when you go in for local smog testing, which is a quickie test with little correlation with the official EPA test in Ann Arbor? And how could this simple-minded cheat against the quickie test work to cheat the full-blown EPA test used to qualify that model.
Something doesn't "compute" in the press accounts, which parrot the same level of understanding, even by Consumer Reports, who are "shocked, shocked" that they had recommended this fuel efficient car to their readers, who may be stuck with a fuel guzzler from following this recommendation after VW uploads new software into their engines?
Paul Milenkovic As BaltACD offered so glibly, yes, there will be litigation to answer that question, but us tech geeks want to get to the bottom of this . . . now! Do the people in the media even understand the difference between the Corvette tuned for light-throttle operation to meet EPA that owners never use and more blatant detection-of-being-under-test?
Don't worry - in the litigation enough engineers for either side will go on record disputing every number, comma, decimal point and sensor outputs - enough that even other engineers will fall asleep in trying to decode and decypher what each side is attempting to say. It's what engineers do.
No one has asked the key question. "How many TDI's does it take to spew as much as one SD70ACe" (or other locomotive of your choice...)
The capacity of these engine computers today is infinite. We went from 20 years ago a simple injector pulse width table, injector control pressure table for an ECM/PCM. Now you have 1000's of tables all shown in 3D histogram. The diesel injectors fire 5 times on each compression stroke. Exhaust regeneration is done by firing the injectors on the exhaust stroke. With fuel at 36,000psi. Also you have capacity for multiple program files and extra tables, and you could revert tables based on conditions or an input, you could have the PCM revert to low NOx setting based on XYZ input or condition. Which I believe is what has occured here. Many diesel vehicles VW, BMW, MB use the same Bosch EDC17 Computer and Bosch CPx fuel pump.
The issue is under certain conditions, the TDI 2009-2014 Jetta could produce up to 40x the NOx (Nitrogen Oxide) EPA rating. NOx is basically created by high cylinder temps. To lower NOx, need more EGR gas recirculated and, less boost, etc. Basically take all the power out of it and blow it down with spent exhaust gas. NOx itself is a particle smaller than what our human lungs can filter, thats the concern. All engines create some NOx. By using Urea with a catalyst NOx is turned back into Nitrogen.
One part that I noticed with these vehicles (The VW Jetta TDI). They were one of the few veichles you could buy up till 2014 that didn't have Urea injection. Nearly every other diesel vehicle has Urea/DEF injection to meet emissions. The odd part comes in where the larger VW Passat TDI has used urea injection with the same engine (VW 2.0)
My theory there is this 2.0 TDI VW engine is basically at the emissions threshold with a lighter jetta, vs. a larger heavier passat would require more fuel to create enough power for the EPA drive cycle. Thus requiring Urea.
However its in the manufactures best interest to design an engine not requiring Urea, if possible. It adds a considerable cost in equipment, additional price tag, hurt sales.
To be price competitive I believe VW, tried to cleverly meet emissions without Urea in the 2009-2014 VW Jetta, but may have found they wern't quite there so had to think outside the box and use some creative engineering.
Mazda has been working on Mazda6 Skyactive D (Diesel) for US Market going on 5 years now. Its been delayed 2 years. They said they could meet emissions without Urea or aftertreatment. More recetly according to Mazda i've heard They've employed a catalyst to allow a performance improvement. Still not ready for market.
I'd have to wonder if another manufacture tipped off this investigation.
I'm going to guess the resolution here will be to install Urea and a revised SCR catalyst on these Jetta's. Most likely will hit VW for $4,000 - $5,000 each car to be modifed, and probably have to buy those owners DEF/Urea/Adblue for the lifetime of the vehicle, in addition to any EPA fine incurred.
Hope this helps, wait and see what happens next.
A guy-in-the-office-who-works-on-computers told me he heard that the Volkswagen "cheat" had something to do with sensing whether the steering wheel was moving (as it would, even on a straight road) or staying put (as it would in a test, either the official one in Ann Arbor that takes place on rollers in a lab or whatever test is done for smog inspection. He also thought it had something to do with sensing changes in tire pressure (such as hitting bumps) using the system for telling if you have a flat tire.
With that clued, I added the search term "steering wheel position" and I came up with a link to the actual letter mailed from EPA to the executives and VW
https://www.techdirt.com/articles/20150920/03163032307/vw-accused-using-software-to-fool-emissions-tests-welcome-to-internet-cheating-things.shtml
This kind of thing could not have been a "hack" thought up by a bunch of engineers in the company and fobbed off on management. Pretty high levels of management had to have "signed off on this." At the same time, the engineers had to have been compromised in their ethics to 1) accepted the management orders to go ahead with this plan and 2) to have thought of this scheme in the first place (it must have required some serious engineering "brainstorming" to come up with, "Hey, let's see if the steering wheel is moving and let's get the sensor for that from the Stability Control safety system!")
This business of Diesels and the onerous emission regs and what compromises people are willing to make is serious business. It affects not only a segment of the passenger car market aimed at fuel efficient autos, it affects the OTR trucks and Diesel trains that bring all the goods that we use, and through the regs on reefer units, it affects the very food that we eat. The whole market for Diesel locomotives is on hiatus because the railroad companies don't want to "deal with DEF", and it seems that one car maker had the same attitude.
And we can gloat about a foreign company being hit with 18 billion dollars in fines, and joke about lawyers and litigation (I am talkin' to you, BaltACD), but there are a whole lot of car owners out there who will be required to "bring their cars in" to make them run less well from the driver's and owner's perspective.
And the difficulty of meeting emissions with Diesels along with the 'tude of the regulators "you guys just fix this and make it happen" without regard for feasibility or weighing the benefits to the environment of fuel efficiency and low carbon emission against the harm from the emissions of NOX and particulates is serious business. As is the impending PTC train wreck on January 1, 2016, which has a similar set of issues.
This Diesel thing must be "that intractable" to get the management of VW to risk such a thing and the engineers at VW to sell out their professional ethics and reputations of such a thing.
Quite apart from whether VW are the only company doing this, it is bigger than the EPA vs VW, which will make many lawyers very rich....
Outside the USA, VW have indicated that 11 million vehicles worldwide are affected. Apparently Angela Merkel has briefly stopped worrying about refugees from Syria to be unhappy about VW.
So if 11 million VW drivers are about to get poorer performance combined with higher fuel consumption, at considerable expense to VW just to acheive that, some unhappiness must ve visited upon the regulators...
The "Techdirt" link doesn't say how the testing revealed the discrepancy but the logical conclusion is that some on road testing with portable gas analysers must have been involved. If the car was on a dynamometer, the program would have detected it.
As someone who carried out on road testing of freight cars, I'm pleased.
In Australia, diesel locomotives are subjected to very stringent noise limits, partly because the largest coal export line runs through a suburban area. There are limits to what you can acheive with sound barriers, so silecing the locomotives is next. These units have mufflers the full length of the engine and nearly as big as the engine. The next target is dynamic brakes. These are tested by running the alternator output direct to the resistor grids. This is of course static testing. So nobody ever measures the sound of the traction motors in dynamic brake. So what do you hear first...?
M636C
Paul Milenkovic This business of Diesels and the onerous emission regs and what compromises people are willing to make is serious business. It affects not only a segment of the passenger car market aimed at fuel efficient autos, it affects the OTR trucks and Diesel trains that bring all the goods that we use, and through the regs on reefer units, it affects the very food that we eat.
This business of Diesels and the onerous emission regs and what compromises people are willing to make is serious business. It affects not only a segment of the passenger car market aimed at fuel efficient autos, it affects the OTR trucks and Diesel trains that bring all the goods that we use, and through the regs on reefer units, it affects the very food that we eat.
One oft repeated comment on the VW TDI cars was that the on-road mileage was usually better than the EPA mileage, which almost never happened with other cars. Not too surprising that was done by bypassing the emissions controls, presumably by disabling EGR when not in test mode.
I do wonder about the EPA enforcing the proposed standards for OTR mileage, where their goal is to double the mileage for a large semi and have cleaner running to boot. Whateve it is the folks at the EPA are on, they need to share...
One of the fallouts from this fiasco is that the EPA will probably get more access to the ECU code. One wonders if they will be setting themselves up for liability if they come across a software "feature" such as the Toyota un-intended acceleration bug and don't say anything about it?
Hello, folks! Please be mindful to keep on topic of how this relates to locomotive emissions. Thank you!
Angela Pusztai-Pasternak, Production Editor, Trains Magazine
Angela,
Point taken.
One of the reasons that VW put the "switches" in the Engine Control Unit (ECU) software was to reduce fuel consumption in actual driving as opposed to the simulated driving during the emissions test. The use of EGR to control NOx presents a tradeoff between lowering fuel consumption and NOx. Since diesel fuel is one of the major operating expenses of running a railroad, anything that increases fuel consumption will meet with some resistance from the RR's.
The question that Paul M may have had on his mind when starting this thread is whether the makers of Tier IV compliant locomotive engines could sneak a "defeat switch" in the ECU to reduce fuel consumption in everyday operation as opposed to being on an emissions test stand. This is not an unreasonable question as Cat, Cummins and a few other diesel engine makers were caught putting defeat switches on their large engine ECU's back about 15 years ago.
erikem Angela, Point taken. One of the reasons that VW put the "switches" in the Engine Control Unit (ECU) software was to reduce fuel consumption in actual driving as opposed to the simulated driving during the emissions test. The use of EGR to control NOx presents a tradeoff between lowering fuel consumption and NOx. Since diesel fuel is one of the major operating expenses of running a railroad, anything that increases fuel consumption will meet with some resistance from the RR's. The question that Paul M may have had on his mind when starting this thread is whether the makers of Tier IV compliant locomotive engines could sneak a "defeat switch" in the ECU to reduce fuel consumption in everyday operation as opposed to being on an emissions test stand. This is not an unreasonable question as Cat, Cummins and a few other diesel engine makers were caught putting defeat switches on their large engine ECU's back about 15 years ago.
I understand, erikem. Please continue to discuss. I received a couple of complaints about it getting off the topic of railroading. I hope you understand that the job of "moderator" is not an easy one. My workday does not permit me to read every thread and digest it. By all means, carry on.
M636C Angela Pusztai-Pasternak wrote the following post 2 hours ago: erikem Angela, Point taken. One of the reasons that VW put the "switches" in the Engine Control Unit (ECU) software was to reduce fuel consumption in actual driving as opposed to the simulated driving during the emissions test. The use of EGR to control NOx presents a tradeoff between lowering fuel consumption and NOx. Since diesel fuel is one of the major operating expenses of running a railroad, anything that increases fuel consumption will meet with some resistance from the RR's. The question that Paul M may have had on his mind when starting this thread is whether the makers of Tier IV compliant locomotive engines could sneak a "defeat switch" in the ECU to reduce fuel consumption in everyday operation as opposed to being on an emissions test stand. This is not an unreasonable question as Cat, Cummins and a few other diesel engine makers were caught putting defeat switches on their large engine ECU's back about 15 years ago. I understand, erikem. Please continue to discuss. I received a couple of complaints about it getting off the topic of railroading. I hope you understand that the job of "moderator" is not an easy one. My workday does not permit me to read every thread and digest it. By all means, carry on. Certainly, I've had the relevance to railroading at the top of my mind. Volkswagen's 2.0 TDI engine was one of the few that attempted to meet the current emission regulations without the use of urea and aftertreatment. This is relevant since the railroads are insisting that their Tier 4 freight locomotives not use urea and aftertreatment. Both the new GE engine (Designation so far not known) and the new EMD engine which seems to be called the 1010 from its cubic capacity in cubic inches, are clearly equipped with exhaust gas recirculation (EGR) equipment, as seen from published photos of the engines. I asked an EMD engineer at a trade show and he indicated that the processes were commercial in confidence and he couldn't confirm or deny this. While the Volkwagen engine could just meet the emission requirements using EGR, its performance and fuel economy were unsatisfactory. The ECU "dual program" for testing and normal operation overcame this problem but didn't meet the emission regulations, although this wasn't obvious to the regulators. The railroads are opposed to urea in freight locomotives presumably because the rate of use of urea would require the urea to be topped up between service periods (around six months for modern locomotives). The concern is that since only Tier 4 units required urea, a railroad that received a tier 4 unit on run through in exchange for an earlier unit would need to top up the urea on the foreign unit while the railroad with its Dash 9 did not need to do this. It is much easier for everybody if the locomotives only need the same supplies (fuel, coolant and sand). But the inference to be drawn from the Volkswagen revelations is that the Tier 4 units will, to some extent, have less power and higher fuel consumption. One of the quotes was "Volkswagen were the only cars where fuel consumption was better than the EPA estimate". The laws of physics and the engineering concerns for a small diesel engine are similar to those for a large engine, except for specific scale factors. We have all been watching the blue GE tier 4 test units. Clearly they can still pull their weight (literally) but the fuel consumption in doing this, and to a lesser extent, the response to throttle inputs are not visible to outside observers. Norfolk Southern have, as far as they can, opted out with extensive rebuild programs that minimise their exposure to Tier 4, possibly until the technology has been more fully developed. It is possible that readers of the thread without engineering degrees have been missing the connections with recent locomotive developments. M636C
Really well put!
I think you nailed it. VW's decision to try to get by without urea is looking to be unwise. I wonder if the same will prove true for the RRs.
An analogous situation would be when the automakers tried to get by without unleaded fuel and catalytic convertors. Anybody remember how "wonderful" 1973/74 cars were? Huge engines. No HP. Lousy gas mileage.
BTW, VW does use AdBlue on the 2015 2.0L TDI in the US. I noticed VW has these cars for sale at a big discount. Good time to buy if you're in the market.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
The Volkswagen scandal may probably have wider consequences than you realize.
For a start, there are rumors about some BMW diesels having a similar behavior (higher pollutants when not in static test).
Lower emissions, higher horsepower, better mileage: select any two.
N.F.
oltmannd An analogous situation would be when the automakers tried to get by without unleaded fuel and catalytic convertors. Anybody remember how "wonderful" 1973/74 cars were? Huge engines. No HP. Lousy gas mileage.
A bit off topic perhaps... I remember how wonderful the 73-79 cars were. The '75 model year cars were little better if at all than the 73/74 cars with the exception of a very significant reduction in emissions. The other problem with the 1973/74 cars was the increase in weight due to newly imposed safety requirements. The real dogs of that era were the 1975 BMW's and Mazda's which both used thermal reactors instead of the catalytic converters.
One reason why catalytic converters weren't used before the 1975 model year was that the infrastructure for selling unleaded gas wasn't completely in place. Since a tankful of leaded gas could ruin a converter, it was imperative that unleaded gas was available everywhere before catalytic converters could be widely used.
To get a bit back on topic: One of the changes in the 1975 model year was the lowering of the limits on NOx. The standard way of meeting those requirements was running the engine rich to kill NOx, but generating a lot of CO and unburned hydrocarbons. The catalyic converter did a good job of burning the CO and HC's with the addition of some air in the exhaust. The thermal reactor needed an even richer mix of CO and HC to complete combustion. IIRC, the 1975 BMW 530i was rated at something like 12MPG.
In the early 1970's, Universal Oil Products had developed a three way catalyst that could handle CO, HC's and NOx, but required a perfect stoichemetric mixture to do so. A couple or so years later, a Volvo engineer was reading an issue of NASA Tech Brief's with an article on an oxygen sensor developed under NASA auspices. This in conjunction with the three way UOP catalyst allowed Volvo to get significantly better mileage and still meet emission specs. It's now hard to find a "gasolene" engined car that doesn't have a three way catalyst. Further improvements have come from modifying cylinder heads to locate the sparkplug closer to the center, which allows for a quicker burn of the fuel, which requires less spark advance and reduces the NOx to boot.
I'm wondering if the powers that be at the various regulatory agencies are thinking that there is some magic bullet with diesel engines that corresponds with the three way catalytic converter. The closest is urea - I remember using urea in freshmen Chem lab to react with the N2O4 from one experiment and thinking this might work on the brown haze in smog - this was spring of 1973.
- Erik
erikem oltmannd An analogous situation would be when the automakers tried to get by without unleaded fuel and catalytic convertors. Anybody remember how "wonderful" 1973/74 cars were? Huge engines. No HP. Lousy gas mileage. A bit off topic perhaps... I remember how wonderful the 73-79 cars were. The '75 model year cars were little better if at all than the 73/74 cars with the exception of a very significant reduction in emissions. The other problem with the 1973/74 cars was the increase in weight due to newly imposed safety requirements. The real dogs of that era were the 1975 BMW's and Mazda's which both used thermal reactors instead of the catalytic converters. One reason why catalytic converters weren't used before the 1975 model year was that the infrastructure for selling unleaded gas wasn't completely in place. Since a tankful of leaded gas could ruin a converter, it was imperative that unleaded gas was available everywhere before catalytic converters could be widely used. To get a bit back on topic: One of the changes in the 1975 model year was the lowering of the limits on NOx. The standard way of meeting those requirements was running the engine rich to kill NOx, but generating a lot of CO and unburned hydrocarbons. The catalyic converter did a good job of burning the CO and HC's with the addition of some air in the exhaust. The thermal reactor needed an even richer mix of CO and HC to complete combustion. IIRC, the 1975 BMW 530i was rated at something like 12MPG. In the early 1970's, Universal Oil Products had developed a three way catalyst that could handle CO, HC's and NOx, but required a perfect stoichemetric mixture to do so. A couple or so years later, a Volvo engineer was reading an issue of NASA Tech Brief's with an article on an oxygen sensor developed under NASA auspices. This in conjunction with the three way UOP catalyst allowed Volvo to get significantly better mileage and still meet emission specs. It's now hard to find a "gasolene" engined car that doesn't have a three way catalyst. Further improvements have come from modifying cylinder heads to locate the sparkplug closer to the center, which allows for a quicker burn of the fuel, which requires less spark advance and reduces the NOx to boot. I'm wondering if the powers that be at the various regulatory agencies are thinking that there is some magic bullet with diesel engines that corresponds with the three way catalytic converter. The closest is urea - I remember using urea in freshmen Chem lab to react with the N2O4 from one experiment and thinking this might work on the brown haze in smog - this was spring of 1973. - Erik
Interesting info! Thanks.
I remember some gas stations selling starting to sell "low lead" gas prior to 1975. That had to be the infrastructure for unleaded being put in place... I also seem to remember a lot of stations giving up on premium in order to handle unleaded.
Our 1974 Ford wagon with a 400cid V-8 got 9.8 mpg over its 140,000 mile life. Ugh.
erikemI'm wondering if the powers that be at the various regulatory agencies are thinking that there is some magic bullet with diesel engines that corresponds with the three way catalytic converter. The closest is urea - I remember using urea in freshmen Chem lab to react with the N2O4 from one experiment and thinking this might work on the brown haze in smog - this was spring of 1973.
The achilles heal(s) of diesels are NOx and soot. High pressure and temp just burns the nitrogen that is the bulk of our atmosphere. EGR and injection retardation reduces peak pressure and temp, but just kills the efficiency. It does seem that urea exhaust treatment would be almost magic.
Patriculate traps for soot are considerably less magic...
Hello Everyone,
this thread brought up a question. How are the new GE diesels that meet Tier 4 emissions doing? Are there any issues, any break downs? Is the technology holding up?
Frank
"If you need a helping hand, you'll find one at the end of your arm."
da_kraut Hello Everyone, this thread brought up a question. How are the new GE diesels that meet Tier 4 emissions doing? Are there any issues, any break downs? Is the technology holding up? Frank
If the car has a built in GPS it could tell that it's stationary, but in drive spinning the tires at 30mph. Or if just the drive tires are spinning and the other two aren't, the wheel speed sensors reading would tell the computer that we are being tested or we are stuck in a snow bank in St.Paul Mn.
Modeling the "Fargo Area Rapid Transit" in O scale 3 rail.
Both EMD and GE have been playing their cards close to the vest with respect to Tier IV-even more so than usual.
CPM500
This isn't new for GE...
A couple of years ago I saw technical data for the Rio Tinto ES44ACi locomotives. One of the technical changes was to the turbocharger which had been completely redesigned, with, they assured us a 1.5% increase in throughput.
However, what had been changed was the size and location of the main bearings to reduce significantly asymmetric loading on the shaft and bearings. There had been mutterings about turbocharger failures on ES series units, and some of the early Rio Tinto ES 44DCi units failed turbochargers after a couple of days in service.
So I don't believe that the very small performance improvement quoted was anything more than an invented reason to explain a new design of turbocharger which was intended to increase reliability without having to admit that there had been failures in the past.
So why should we expect to hear about any problems with Tier 4?
However, if some improvements to the Tier 4 engines are announced, it might be worth checking to see what was changed, since that might relate to problems not publically admitted...
To date, I haven't seen any ET44 loco number on my carriers's sheet for dead locos that need to be moved to a shop.
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