As a naturally aspirated diesel engine, a diesel engine is called, does not have a charge, whether by turbocharger or compressor has, but by the damage caused by the pulling movement of the piston under pressure the combustion air into the cylinder through the open intake valve feeds ( naturally aspirated ).
Due to the significantly reduced effort to control technology and the lack of such a turbocharger engines are cheaper, easier to maintain and easier troubleshooting as supercharged engines. To this must - with identical displacement - a significant performance penalty to be accepted, which makes such a vehicle equipped appear much tougher in the acceleration characteristics. In return, such engines have a lower error rate and a longer life. In the low speed ranges they give their power willingly, for they do not have a so-called turbo lag.
At Volkswagen, this design was referred to as SDI ( naturally aspirated diesel with direct injection). The Volkswagen Group was also the only manufacturer that had a direct injection naturally aspirated until 9/2010 for cars in the program. Most recently, he was ordered only in the VW Caddy.