Actually, I guess that is not really clear, sorry. The piezoelectric type injectors developed have a lower chamber that holds a certain quantity of fuel (I have some great pics in a Bosch book at work). They are not quite the same as a gas injector that simply opens up a hole by pulling a needle up, the diesel injectors use that lower chamber full of fuel to allow the needle to pull up which allows the use of greater pressures. Then the actual delivery can be stepped or staggered over a longer duration, with much tighter controls. Not a huge single 'WHAM' of fuel with a very sharp taper of delivery. Without them, the injection pressures could not be as high as they are and still be controlled so finely. PDs actually have very high pressures as well, but cannot be controlled as well, thus they still have the signature diesel clatter the CR does not. The CR's injectors allow some method of 'amplification' of the delivery pressures, that is the best way I can describe it.
Here is the best pic I can find:
http://www.blogcdn.com/www.autobloggreen.com/media/2008/09/dfi3.png
So no, the injectors are not "injecting" the fuel, I apologize for that statement, that was not what I meant. I just meant to say that there is much more to them than a gas engine's port injector which is simply an on-off solenoid that is controlling a pintle that is either open or closed.
So the load on the belt does not have the violent jerks and such that the previous systems (especially the PD) did. The load is more constant and linear. The load on the PDs is so great the teeth on the crank sprocket are actually not spaced or shaped the same all the way around, but are ever so slightly different to counteract the extreme pulsing of the belt drive system. If VAG can make the PD's belt drive work (and they do, have not seen one fail yet) then the CR is easy.