afretes

Audi says the "world's cleanest diesel engine" will make its debut in the Audi Q7 early next year.
No single advancement accounts for a combined reduction in hydrocarbons, oxides of nitrogen and particulates by 95 to 98 per cent from 1989 levels. Rather, the solutions lie in a collection of technologies.

A COMMON RAIL FUEL INJECTION SYSTEM:

The fuel injection system starts with a high pressure pump and an injection rail for each cylinder bank. However, Audi is also using piezo injectors, which are widely seen as the next big step in the evolution of the diesel engine.
Piezo injectors have small crystalline discs in the injector which change shape when electricity is applied. When the discs change shape, diesel fuel under high pressure is shot through a needle in a fine spray into the engine's combustion chambers.
Audi's TDI injectors in the 3.0-litre can make as many as five fuel injections in a single piston stroke, compared with one or three injections in most diesel engines. The multiple injections lower the temperature in the combustion chamber, which in turn lowers nitrogen oxides (NOx) emissions.
In addition, piezo injectors reduce noise, vibration and smoke, all unpopular traits of a diesel engine.
To aid combustion efficiency, Audi says it has improved the exhaust gas recirculation design to improve engine efficiency and reduce NOx emissions.
Audi officials also say they optimized turbocharging to get the most out of the boost provided by using exhaust gases to drive the turbo system.

DIESEL PARTICULATE FILTER:

Particulates, relatively large chunks of exhaust that can literally float in the air, are trapped by a robust filter located upstream in the exhaust system.

ADBLUE EXHAUST TREATMENT:

Currently, there are two ways to reduce smog-causing nitrogen oxides (NOx) - a Selective Catalytic Reduction (SCR) filter or a lean NOx trap. The SRC filter is the most efficient way to reduce NOx.
AdBlue is Audi's version of an SRC filter. In this case, Audi has engineered a urea treatment for dramatically reducing NOx and it goes by the trade name AdBlue. (Mercedes-Benz calls its version Bluetec.)
In essence, a urea solution from the AdBlue tank is squirted into the exhaust at what Audi calls the DeNOx catalytic converter. The urea solution breaks down into ammonia, which the nitrogen oxides then split into nitrogen and hydrogen, thus removing a large chunk of NOx emissions. Two NOx sensors help determine the volume of urea treatment.
The AdBlue tank is refilled at the fuel tank flap whenever the car is brought to the dealer for service. If the tank runs dry, a warning signal appears in the instrument cluster. The fuel tank is heated to keep the solution from freezing in temperatures below minus-11 C.

Jerry D

Just think of the wow factor of telling people your car runs on heated pee

April

if he can get it there.

He has an old diesel Pajero (for really grungy jobs) and Trooper (for hauling people) for plantation work, and an E39 for business meeetings. But he finds the BMW dull compared to his Alfas (which are unfortunately viewed as playboy cars and not suitable for business), and so is looking at other options. I really hope he likes the new A4 and that they get the diesel option, because it would be so cool to really check it out on highways that aren't very well patrolled (they just use manual cameras and send you photo tickets).

:-D

B_S373N

Hehee so novel. Except if a buddy takes it to the next level and wees in your gas tank...

afretes

Hey Nelson, did you get the washer fixed?

B_S373N

LOL no, I'm going to call today...horribly busy.