Defective sensor?

Please can you help me locate the name and the function of a sensor which is situated on the left bank beside the injectors, it got broken and I have difficulties starting the car. I will send an image of this part I took before replacing my head gasket.

This is a Q7 supercharged 3.0Tsfi, and this sensor is located beside the 3 left injectors when standing in front of the engine. Mine got broken, I need to know its name and function please.

I forwarded the image.