26 September 2015

Piss Tanks and Soot Cookers

Dammit. Every time diesel looks like it might take off in the USA....

You either love driving diesels or you don't; I fall into the first camp. Since my first 1978 Oldsmobile diesel, purchased used in the early eighties, I've enjoyed the fuel economy, range, and operation of the diesel engine and haven't stuck a gasoline pump nozzle into a car I've owned since. I've had four cars powered by five of those infamous 5.7 liter Oldsmobile diesel engines, and none of them owed me a thing—and I knew what I was getting into.

I did manage to work my way up to a car I lusted for when it was new, and could afford to buy about two decades later: a near pristine and low-mileage Mercedez-Benz 300SDL, the top-of-the-line, long-wheelbase version S-Class—the "Big Benz"—but with a 3-liter in-line 6-cylinder diesel rather than the 5-liter V-8 gas monster that more appealed to the American buyer who could afford to blow 50,000 1987 dollars on a car.

About a year ago someone did me the favor of hitting me head-on—thankfully not at high speed—and totaling my beloved old SDL. I say "favor" because a decision needed to be made about putting some funds into cosmetic work for the car as my real life Connecticut winter driving had taken its toll on this previously pampered baby. The thousands I would have spent would have yielded little return beyond my pride, so the timing was good. I was forced into what I pretty much had predetermined would be my next car: a Volkswagen Passat with the TDI engine. I wanted to go smaller in size, higher in fuel economy, and less prestigious and conspicuous in brand and status. The Passat was all that and more, and fit my requirements perfectly. I just didn't want it quite yet. In probably one of the quickest sales a dealership has ever seen, I parked my ass in a brand new 2015 Passat SE TDI with a fun-to-drive 6-speed stick. Save for that third pedal, about the dullest and fartiest vehicle in the VW lineup. Perfect.

About ten months and six thousand miles into the Passat I remained pleased as punch: nice car to drive, 48-50 miles-per-gallon, 800 mile range, and, pry the VW badges off the bow and stern and it could be a Camry or an Accord, the car is so nondescript. A car I could like but not worship. And finally, I could spout my unsolicited preaching of the joys of driving a diesel and now include, delivered with smug superiority, "clean running."

Along came "DieselGate."

Within days an almost surreal story unfolded telling of willful cheating by Volkswagen to alter the results of emissions, blossoming into what is looking like a quagmire second only to something you might not be surprised to find on Wall Street, but would never expect from Wolfsburg. This public relations nightmare will require an enormous amount of damage control and perhaps billions of dollars to make it better—it's hard to imagine at this point ever making it right.

There have been some changes in diesel emission controls having come two decades and crossing a millennium from my last to my current model year car. Where once upon a time, the "diesel emission system" consisted of and remained the same basic and primitive closed crankcase, positive crankcase ventilation (PCV) and exhaust gas recirculation (EGR) found in cars since the seventies, it's gotten way more complicated today. Electronics have reached the diesel engine, for fuel delivery, throttle/speed control (I reckon the good old flyweight governor is dead), valve timing—and emissions. Once upon that same time, after you got a diesel engine started the only thing you needed to keep it running (or stop it) was fuel (or no fuel). Those days are gone. Without a battery or alternator, you're just as stuck with a diesel as you are with a gas engine now.

My first startling experience with the emission controls in my TDI was the diesel particulate filter regenerator, or DPF, and its first- and second-cycle signature smell of burning plastic, the same kind of plastic found everywhere in automotive controls that, when it burns, makes you go straight to thinking something electrical is about to go up in flames (typically a switch, often headlight or dimmer). The diesel exhaust system is no longer nothing more than manifold, muffler and piping. Even the catalytic converter—lack thereof long a bonus of owning a diesel—has found its way to the diesel. I'm guessing a lot of this stuff is why you see so many buses on fire these days, due to intense heat where there never used to be in a more crowded engine compartment.

Particulate matter (soot), CO and sulfur derivative issues have been dealt with using reasonably simple and reliable controls, filters and re-blending of fuels. But nitrogen oxides (NOx) is the tough one to tackle. Enter the "piss tank," which holds "diesel exhaust fluid," or DEF. This magic urea cocktail (hence the various urine-themed slang terms) is injected into the system after combustion to reduce NOx. It also adds another never-before maintenance routine, the need to top off this tank of juice. Fortunately, the diesel exhaust has not gone from smelling like the odor I know and love to smelling like a busted urinal in a dive bar on a Sunday morning. (The "fry-o-lator" smell of biodiesel exhaust is bad enough.) But this stuff ain't cheap, and its consumption is directly related to driving habits and engine load.

Since the discovery of extremely high NOx output seems to be the main problem here, I'm betting that the hack was to reduce the consumption of DEF to avoid "inconveniencing" the customer by stretching out refills to last long enough to make it to the next oil change or service, thereby not causing an additional interim service scheduling annoyance and expense.

My best guess is that the combination of reasons VW went to such reckless lengthsWTF were they thinking? lengthsto defeat this system except when sensing emissions rating and testing is basically three-fold:

  1. Maintain fuel economy;
  2. Maintain performance;
  3. Reduce maintenance costs (DEF replenishment, expendable filters/parts).
Since it's all controlled electronically, turning the system on or off is as simple as, well, turning the system on or off. What they are inevitably calling the "VW Bug" (it's actually more hack than bug, as it's intentional, not accidental) might be connected to rear wheel movement, hand-brake position, steeringjust about anything that does something different under normal driving conditions than when chocked in a dynamometer for testing.

I like the car and would rather not look for an excuse to get rid of it. If VW wants to somehow compensate us beyond a "free" recall, I'm open to a gesture. Cash is nice. I won't quibble over a small performance hit, but anything beyond a tiny ding in my fuel economy and I will be pissed. Resale value is not a large concern of mine since I tend to drive cars into the ground, but nobody, particularly a diesel fanatic like myself, likes going from preaching all his annoying clean diesel gospel to being shamed and embarrassed by driving the pariah of the road.

As parents are wont to say, looking to induce guilt and shame, I'm more disappointed than I am angry with VW's behavior. At least all those Lemon Law-tainted Olds diesels I fancied were bad engines thanks to designer incompetence, not willfully unlawful and deceptive behavior. And I bought all those cars, priced accordingly, after the cat was out of the bag.

No comments:

Post a Comment

Differences of opinion are welcome, but please keep it civil. All comments moderated, so flames will be extinguished.