The Direct Shift Gearbox (DSG),

What it is and how it works
The Direct Shift Gearbox (DSG), also known as S-Tronic or the double-clutch gearbox, is a transmission developed by Audi and Volkswagen. What makes it special is that it can change gears faster than any other geared transmission. The DSG can be shifted either manually or automatically. It delivers more power and better control than a traditional automatic transmission and faster performance than a manual transmission.
The DSG is a development of the sequential manual transmission (SMT), which is essentially a fully-automated manual transmission with a computer-controlled clutch. Before we delve into the workings of the DSG, let's start with an explanation of the SMT.
SMT: The control of a manual with the ease of an automaticThough it has appeared on a few passenger cars, the SMT is widely used in certain forms of racing and is featured on Ferrari's Enzo supercar. Most SMTs can be shifted automatically or manually, the latter using a shift lever or paddles on the steering wheel. The advantage to an SMT is that it uses a solid coupling, as opposed to a fluid coupling (torque converter) as used in a traditional automatic (including Tiptronic- or manumatic-style transmissions). As with a manual transmission, the SMT provides a direct connection between engine and transmission, allowing 100 percent of the engine's power to be transmitted to the wheels. The SMT provides more immediate response and ensures that the engine RPMs do not drop when the driver lifts off the accelerator (as happens with an automatic), giving her more precise control over power output.

SMTs can also perform matched-rev (or double-clutch) downshifts:
When the driver downshifts, the SMT disengages the clutch, shifts to neutral, and re-engages the clutch. The SMT calculates what the engine RPMs will be in the next-lowest gear based on the current road speed, and revs the engine (and, since the clutch is engaged, the transmission) to that speed. It then disengages the clutch, shifts into the lower gear, and re-engages the clutch. The result is a smooth change with no jerk and no sudden deceleration.

SMTs have one major disadvantage, same as a manual:
Power must be interrupted while the transmission changes gears.
DSG: An SMT without the lagThe DSG/S-Tronic all but eliminates the lag inherent in SMTs. The DSG is essentially two 3-speed gearboxes with a pair of clutches. When the driver starts out, transmission #1 is in first gear and transmission #2 is in second. The clutch engages and the car starts out in first. When it's time to change gears, the DSG uses the clutches to swap transmissions. The #1 transmission immediately shifts to third gear. At the next change the DSG swaps transmissions again, and #2 shifts to fourth. The DSG's computerized controller calculates the next likely gearchange and shifts the "idle" transmission into that gear. The advantage is the speed of gearchanges: The DSG takes about 8 milliseconds to upshift. Compare that to the SMT in the Ferrari Enzo, which takes 150 ms to upshift. It's also significantly faster than a human: According to Audi, the A3 runs 0-60 in 6.9 seconds with a 6-speed manual and 6.7 seconds with the 6-speed DSG. Like the SMT, the DSG performs double-clutch downshifts and can skip gears (i.e. downshifting from 6th directly to 4th, 3rd, etc).
Driving with the DSGThe DSG uses a traditional P-R-N-D-S shift pattern. It can shift automatically in either normal (D) or Sport (S) modes. In Normal mode, the DSG shifts to the higher gears early in order to minimize engine noise and maximize fuel economy. In Sport mode the transmission holds the lower gears longer in order to keep the engine in its powerband. This is especially useful for turbocharged cars like Audi A3, Volkswagen GTI and VW Jetta GLI, since the turbocharger is only active at higher RPMs. Sport mode also provides more aggressive downshifts with slight accelerator pedal pressure.
Manual mode is engaged by either sliding the shift lever to the side or pulling one of the paddles on the steering wheel. Once in manual mode, shifts are made by moving the shifter fore and aft or using the paddles (which are marked " " and "-"). If manual mode was engaged with the paddles, pulling and holding the upshift paddle returns the transmission to automatic mode, allowing the driver to quickly downshift to a lower gear for passing and then hand control back over to the transmission.
Cars with SMTs have no clutch pedal; the clutch is automatically engaged

Direct Fuel Injection

What it is, how it works
Direct fuel injection defined
Direct fuel injection is a fuel-delivery technology that allows gasoline engines to burn fuel more efficiently, resulting in more power, cleaner emissions, and increased fuel economy.

How direct fuel injection works
Gasoline engines work by sucking a mixture of gasoline and air into a cylinder, compressing it with a piston, and igniting it with a spark; the resulting explosion drives the piston downwards, producing power. Traditional fuel injection systems pre-mix the gasoline and air in a chamber just outside the cylinder called the intake manifold. In a direct-injection system, the air and gasoline are not pre-mixed; air comes in via the intake manifold, while the gasoline is injected directly into the cylinder.

Advantages of direct fuel injection
Combined with ultra-precise computer management, direct injection allows more precise control over fuel metering (the amount of fuel injected) and injection timing (exactly when the fuel is introduced into the cylinder).

The location of the injector also allows for a more optimal spray pattern that breaks the gasoline up into smaller droplets. The result is more complete combustion -- in other words, more power from each drop of gasoline.

Disadvantages of direct fuel injection
The primary disadvantages of direct injection engines are complexity and cost. Direct injection systems are more expensive to build because their components must be more rugged -- they handle fuel at significantly higher pressures than indirect injection systems and the injectors themselves must be able to withstand the heat and pressure of combustion inside the cylinder.
How much more powerful and efficient is direct injection?
Cadillac sells the CTS with both indirect and direct injection versions of its 3.6 liter V6 engine. The indirect engine produces 263 horsepower and 253 lb-ft of torque, while the direct version develops 304 hp and 274 lb-ft. Despite the additional power, EPA fuel economy estimates for the direct injection engine are 1 MPG higher in the city (18 MPG vs 17 MPG) and equal on the highway. Another advantage: Cadillac's direct injection engine runs on regular (87 octane) gasoline. Competing cars from Infiniti and Lexus, which use 300 hp V6 engines with indirect injection, require premium fuel.

Renewed interest in direct fuel injection
Drawing of a direct injection system -- note the injector on the far right at the top of the cylinder
Direct injection technology has been around since the mid-20th century; however, few automakers adopted it for mass-market cars. Electronically-controlled indirect fuel injection did the job nearly as well at a significantly lower cost, and offered huge advantages over the mechanical carburetor, which was the dominant fuel delivery system until the 1980s. However, recent developments such as skyrocketing fuel prices and stricter fuel economy and emissions legislation have led many automakers to begin developing direct fuel injection systems. You can expect to see more and more cars make use of direct injection in the near future.

Diesels and direct fuel injection
Virtually all diesel engines use direct fuel injection. However, because diesels use a different process to combust their fuel (gasoline engines compress a mixture of gasoline and air and ignite it with a spark; diesels compress air only, then spray in fuel which is ignited by the heat and pressure), their injection systems differ in design and operation from gasoline direct fuel injection systems.

Journey's End: A supercar for the common man (provided he's uncommonly rich)

2008 Audi R8
My week with the R8 included an 800-mile round trip to see my folks in Phoenix. Again, the R8 amazed my wife and I with how well it handled such a mundane task. We found the R8 comfortable and, aside from lots of tire noise on rough roads, pretty quiet. I'll plead the fifth on how fast we drove, but I was amazed by the fuel economy: Nearly 20 MPG.
And that's what makes the Audi R8 such a fantastic car. It's not that it looks like a supermodel, or that it goes like a scalded dog, or that it clings to the road like Velcro. What makes the Audi R8 so awesome is that it does all that, yet it still works as a regular daily driver. I could see myself commuting daily through Los Angeles traffic in an Audi R8, and having no complaints save gas mileage (around 12 MPG in town, not a problem if you can afford the R8's four-figure car payment).
The R8 ain't cheap ($112k and no standard navigation system? Cripes!), but it's a bargain by supercar standards: $70k less than a new Lambo and $65k less than a Ferrari. And it's not like you're getting a cut-rate knock-off, either -- Audi owns Lamborghini, and the R8 shares its basic layout (and a few of its parts) with the Gallardo. It looks as good, sounds as good, and gets just as much positive attention from valet attendants and passers-by.
No doubt about it: The R8 is a proper supercar. And it's a great one at that, because you can enjoy its awesomeness every single day. Hmm... I think it's time to ask About.com for a raise. A big one. -- Aaron Gold

2008 Audi R8 test drive

Time was that if you wanted a proper supercar, you went to the Italians -- Ferrari or Lamborghini. But for 2008, German automaker Audi has introduced their first mid-engine supercar, the R8. With a 420 horsepower V8 nestled behind the passenger compartment, all-wheel-drive, and a shape to die for, the 2008 Audi R8 sure has the right resume. But how does it work in real life -- is this the stuff of which dreams are made? Read on. $112,100 base (including destination and gas guzzler tax), $133,045 as tested, EPA fuel economy estimates 13 MPG city, 19-20 highway.
First Glance: Fourteen again
Larger photos: Front - side - rear - cutaway
When I first booked the R8 for a test drive, I vowed I would write a serious review. I'd talk about turn-in understeer and trailing-throttle oversteer and all sorts of high-end performance-related stuff. I'd write as if I drove Lamborghinis and Ferraris and Moslers every day, and the R8 was just another supercar, and, at $112k, a deeply-discounted one at that. Ho-hum, just another day at the office.
All that went out the window the moment the R8 arrived. I instantly turned into a 14-year-old with his bedroom walls covered in posters of Countaches and Samantha Fox. (I grew up in the 80s.) Even now, as I sit here at the keyboard, all I can think is Holy cow, there's an Audi R8 in my driveway! How cool is that? (The answer, by the way, is REALLY FRICKIN' COOL.)
Never mind how fast it is (very). Never mind how well it handles (unbelievable). Never mind how beautiful it is (breathtaking). As I drove the R8, my left brain would ask questions like "Do I detect a bit of front differential binding in sharp turns?" to which my right brain would answer "I'm driving an R8, this is so awesome!"
Bear in mind that the R8 makes it easy to spend all of one's time reveling in its coolness, because it's so incredibly easy to live with. By definition, supercars are temperamental beasts that buck at anything but the open road. Not the R8. You can get in and tell it "We're just going to run down the street to pick up a quart of milk," and it'll say "Sounds good to me," and go about the job with the ease and convenience of a Honda Civic.

The Top Ten Technologies: Fuel Cell Vehicles

The personal automobile is the source of both fantastic benefits to modern life and terrible consequences. Those consequences range from devastating public health effects due to automobile emissions (asthma, lung cancer, throat infections, etc.) to the rapid alteration of our planet's own atmosphere (global warming). But what if a new technology could bring us all the benefits of personal transportation without these drawbacks?
Fuel cell vehicles may deliver on precisely that promise. Fuel cell vehicles (FCVs) don't burn fossil fuels and emit toxic fumes, they take a hydrogen fuel source such as methanol, propane gas or hydrogen gas and convert it directly to electricity to power the vehicle. Like fuel cell battery technology, it's clean for humans, clean for the environment, and safer than carrying around highly explosive liquids like gasoline.
Perhaps even more importantly, it would spearhead the shift away from the global oil economy and free the United States and other nations from their heavy dependence on oil -- the source of tremendous global strife.
There are considerable obstacles to fuel cell vehicles, however: infrastructure obstacles, primarily. Whatever fuel is ultimately chosen for FCVs, we will need an infrastructure of refueling stations ("gas stations"), fuel distribution systems (tanker trucks), fuel refineries, mechanics who can work on such systems, and so on. It's akin to reinventing the entire automobile infrastructure from the ground up. These enormous startup costs remain the primary obstacle to the widespread adoption of fuel cell vehicles, and it's a catch-22 situation: people won't buy the vehicles if there are no refueling stations, and no company will build refueling stations if there are no vehicles waiting to use them.
Hybrid vehicles offer a smart interim solution to this dilemma. While today's hybrid vehicles derive all their power from a gasoline engine, tomorrow's hybrids could be made to run on either fuel cells or gasoline, depending on what's available. Both the gasoline engine and fuel cell would be used to recharge the primary vehicle batteries that provide the operating power. Or the battery could be scrapped and replaced with a zinc fuel cell system where the gasoline engine could kick in when the zinc needs to be recharged. This configuration would eliminate the battery altogether and could still take advantage of the regenerative recharging ability during vehicle braking.
Today's hybrid vehicles like the Toyota Prius have made great strides in the technology needed to mass produce such vehicles. In fact, the Prius is a shining achievement in the marriage of combustion engines and battery technology. Without question, Toyota has the technical mastery and foresight needed to build a fuel cell hybrid vehicle if the public infrastructure will support its use.
We can expect Japanese automobile manufacturers to stay in the lead on fuel cell vehicles, by the way. American car companies are years behind and have resorted to licensing Japanese fuel cell technology rather than creating their own. There are many potential explanations for this lack of vision on the part of American car companies, but there's no denying the fact that the Japanese are leading the field and seem well positioned to continue doing so.

This article has been adapted from, The Ten Most Important Emerging Technologies For Humanity, an ebook by futurist Mike Adams.