Diesel Delights (updated)

April 28, 2012 by  

I love my diesel car! There. I’ve said it. Yes, those slow, smoky, stinky diesels with the filthy gas pumps, and the warnings from service station attendants (cashiers) who sometimes run outside to caution me not to put diesel fuel in my car—that’s only for trucks! Well, maybe that was yesterday’s diesel. Today’s diesel cars have come a long way, baby. Modern diesel-powered cars, usually supplied with turbochargers, can really push you back in your seat if you understand the limitations (more later).

I’m on my second diesel car, a Volkswagen Jetta TDI (Turbo Diesel Injection) Sportwagen. On my daily 85 mile round-trip commute, I average around 42 MPG, while cruising at about 70 MPH. Furthermore, it’s every bit a German car (even though it was assembled in Mexico). The doors close with the authority of a bank vault, unlike my previous car, a Toyota RAV4, which was a fine automobile that gave me excellent service, but the sounds that came from the car when I closed the door can only be likened to a crashing garbage can. Very cheap and tinny. The seats are firm and supportive.  You don’t sink into the seats of a German car. These cars are built for cruising all day on the autobahn at 100 MPH! For this, you need to be alert and comfortable, not coddled and dreamy. As I’ve said in other blogs, you don’t sit in a German car as much as you sit on a German car. It’s safer, too. If you do have to suddenly accelerate, and the seats are soft and unsupportive, punching the throttle could push you so far into your seat (if you like to sit way back) that you could lose your grip on the steering wheel, and we all know that’s NOT a good thing.

NOTE: This story was written somewhere around 2011. In 2013, I traded the Sportwagen in for a 2013 VW Golf TDI. Pretty much everything I said in this blog applies to the Golf, too.

But I digress. The plastics are of a high quality with nary a rattle or squeak. The DSG transmission (more later) shifts with authority, and mostly works with me to ensure I’m in the right gear for my immediate driving needs. But you can probably say that about almost any car, gas, diesel, hybrid, or whatever.

2003 VW Jetta TDI Wagon

I bought my first diesel car, a 2003 VW Jetta TDI station wagon, after trading my beloved VW Passat wagon (yes, I really like wagons—practical, and VW’s wagons are very aesthetically pleasing, to boot). It was the previous generation, which used the older, now banned high-sulfur content diesel fuel. Yeah, it smoked a little when I goosed the accelerator pedal, but it sure was fun to hear the turbocharger spin up like a deranged jet engine (when the windows were open—when closed, you could scarcely hear the engine), and it did give you that lovely push into the driver’s seat when goosed in its optimum engine speed, between about 1600 and 2300 RPM. Off the line, not any great shakes. The turbo needed to get up to speed to pump more air into the cylinders to pump up the power and the torque. Oh, did I mention the torque? Zowie! Stopped on a steep incline at a drawbridge, I could take my foot off the brake and begin moving forward without touching the accelerator pedal. The engine only had about 90 HP, but it had 140-150 foot-lbs of torque, and that made all the difference. I drove it for a little over 100,000 miles (as long as I try to keep any car), and because VW wasn’t offering a diesel car that year (2007), I wound up with the RAV4. I drove it for almost 125,000 miles before I went back to a VW TDI.

For those who don’t know, a diesel engine operates on very different principles than a gasoline engine, which simplify things in some ways, but also complicate them. A gasoline engine uses electric sparks to ignite fuel in the combustion chamber to make the car go. A diesel uses what they call compression ignition. In other words, by using an extremely high amount of compression, some 3-4 times higher than a gasoline engine, the piston moves to the top of its travel, compressing and heating the air, when lord-a-mighty, fuel is rapidly injected into the cylinder under high pressure, and due to the tremendous heat in the combustion chamber, it self-ignites without the need for a spark. This has permitted diesel engines to run on lower-quality fuel, though due to the high amount of sulfur in the fuel, they did smoke a lot. Just think of those big trucks on the interstate with their twin exhaust stacks belching out thick black smoke.

Those days are over, or will be over very soon. Federal exhaust emission standards were toughened a few years ago, requiring the emissions of a diesel engine to be no worse than those of a gasoline engine. This required some serious engineering and testing. Fuel delivery systems had to be tweaked. Pressure in the fuel lines and injectors were increased to as much as 25,000 PSI. Sulfur was removed from the fuel. Soot from the exhaust pipe had to be nearly eliminated. Volkswagen was able to achieve these goals by 2009. What it meant was they had to withdraw their very popular (and profitable) diesel vehicles from the US market for two years while trying to comply with the new emission standards, and while maintaining drivability and fuel economy. When the TDIs were reintroduced in 2009, Volkswagen proved this was so. Mercedes-Benz took a slightly different tack by injecting urea (yes, just what you think it is) into the exhaust stream to reduce certain oxides of nitrogen. This requires a trip to your auto dealer every 10,000 miles or so to replenish the urea container. If you see ads for diesel cars using BluTec technology, it means they inject highly purified and processed animal pee into the car’s exhaust system.  Soot particles were eliminated by capturing them in a small canister where after some period of time, they are reintroduced into the exhaust and burned off. This process is probably responsible for a 2-3% drop in diesel engine economy.

The new VW TDI has a few other tricks up its sleeve. The Europeans have had automated manual transmission vehicles for quite a few years now, but these systems are just now reaching the US shores. In a nutshell, these transmissions, called DSG (direct shift gearing) in VW parlance, are 6-speed manual transmissions with two clutches, all controlled by a computer. As you take off in first gear, second gear is already meshed and ready for action. The computer tells the first clutch to release while engaging the second clutch, all in the blink of an eye. It’s very fast, and other than starting from a dead stop, it sounds and behaves like a conventional automatic. The eerie part is moving away from a dead stop. The engine and transmission make the sounds of somebody (but not the driver) using a clutch to get moving. I say again, very eerie. But it works very well. I’ll find out in about 15,000 miles how expensive this is going to be to service, as a major transmission inspection/servicing comes up at 40,000 miles.

The sound system has a few tricks, too. It has a six-disc CD player, along with the obligatory AM-FM radio, along with Sirius XM satellite radio, and something called MDI (mobile digital interface). MDI is a proprietary VW (and Audi, Bentley, Porsche, Skoda, and a few others) digital audio interface system. It cost me an extra $400 to get it installed. There’s a special cable that plugs into a second cable, which, in turn plugs into the multi-pin receptacle built into the base of my iPod. Other cable options include USB and standard analog audio (with their own unique $35.00 adapter cables). I can control my iPod from steering wheel controls or the touch-screen on the radio. There’s also wireless Bluetooth to control my iPhone, also controlled from buttons on my steering wheel. Very convenient, and you don’t have to take your eyes off the road to answer your phone. The phone’s contact list can be viewed on the dashboard information display (more in direct view of the driver than the radio in the center console), and it all works quite well, other than the occasional pressing of the voice command system button on the sterring wheel, which is a bear to shut off again. Finally, there’s an SD memory card slot on the front of the radio that you can use to play MP3 files stored on the card.

When I first bought the car, I showed it to some of my co-workers. One of them went to the tailpipe, where he noted virtually zero diesel smell, and he also noted how quiet the engine was. VW knows insulation.

I’ve been very happy with the car, and with the fuel economy. Even though diesel fuel costs as much or more than premium gasoline, due to the sulfur extraction requirements, as well as higher highway taxes (gee, only truckers use diesel, and they tear the roads up—let’s make ‘em pay—thus sayeth most state legislatures). But with 42 MPG, I am still dollars ahead of what I was spending on fuel, considering my RAV4 got about 23 MPG on the same driving cycle. With a smaller fuel tank, I only have to fill up once a week. I had to fill the RAV4 twice a week. My new TDI is even more economical than my previous Jetta TDI, which only got about 37 MPG.

1980 Plymouth Champ

1981 VW Rabbit Diesel

It’s so strange that I would up with a diesel at all. My first experience was mixed, at best. Back in 1982, fresh out of the Air Force, and fresh into a new job, I bought a car (Plymouth Champ), but the dealer wasn’t able to deliver it immediately. Because the salesman was a Coast Guard Reserve junior non-commissioned officer serving under my step-brother Bill, and not wanting to offend his commanding officer, he provided me with a loaner—a 1981 VW Rabbit Diesel with a 5-speed manual transmission. This was before VW offered turbochargers in their cars, so this 1.6 liter diesel only had 40 or 50 HP. The power band was so narrow (roughly 1800-2200 RPM) that I learned to stir the 5-speed box…a lot. I was constantly shifting gears up and down to find the optimum place where I could accelerate (and I use that term loosely) and keep up with the moving traffic. It wasn’t easy, I can assure you. And it belched black smoke like an old steel mill. I vowed never to let a diesel darken my door again. Fast forward about 20 years, and diesel technology had advanced by leaps and bounds, making a diesel engine vehicle a viable choice for the discerning driver.

I love my TDI, and encourage car enthusiasts to take a test drive. You may be pleasantly surprised. Oh, if you like shifting your own gears, you can get even better fuel economy by specifying VW’s smooth-shifting six-speed manual transmission.

Postscript: In October, 2015, it was disclosed that Volkswagen (and later determined Porsche and Audi) had used “cheats” to make their cars pass exhaust emission certification tests. Ultimately, it cost Volkswagen somewhere around $15-17 Billion in fines and an enormous buy-back program from which I benefited. In March, 2016, after filling out a bunch of paperwork, I handed an agent from Volkswagen the keys to my beloved 2013 VW Golf TDI, and took an Uber taxi to Wayne Akers Ford in Lake Worth, Florida, to take delivery of my new 2016 Ford Fusion SE Hybrid. Fuel mileage is, if anything, marginally better than the VW, with the added advantages of gasoline being cheaper than diesel fuel, and servicing is MUCH less expensive for the Ford. A typical 5,000 mile servicing on the Ford is well under $100, while a 10,000 servicing on the VW was seldom less that $400-500, and that was before any repairs that weren’t covered by the extended warranty! I liked my VW TDIs then, and I still look back on them with great nostalgia, but the Ford is fine, too. I drive almost 500 miles a week, and it has been a faithful steed.