Fuel additive for improved performance of direct-injection engines with fuel injection

A fuel composition for a diesel engine with direct fuel injection, a method for improving the performance of fuel injectors and a method for cleaning fuel injectors for a diesel engine. The fuel composition includes a main component of a fuel amount and an effective minor amount of a quaternary ammonium salt with a thermogravimetric analysis (TGA) -weight loss of more than 50 wt .-% A at 350 ° C. The amount of quaternary ammonium salt which is present in the fuel is sufficient, the power of the diesel engine with direct fuel injection, wherein the composition has burned, as compared to the performance of such a motor which has burned a fuel composition not containing the quaternary ammonium salt , to improve.