System for taking exhaust gas samples from internal combustion engines

A system for taking an exhaust gas sample from an internal combustion engine, the system comprising:

• an exhaust gas duct comprising an outflow cross section and an exhaust gas inlet, the exhaust gas duct being configured to be in a fluid communication with an exhaust gas source via the exhaust gas inlet;
• an air duct configured to take in ambient air via an air filter, the outflow cross section of the exhaust gas duct being arranged so as to be substantially concentric in the air duct;
• a mixing zone arranged downstream of the outflow cross section;
• a dilution tunnel comprising a center axis, the dilution tunnel being configured to have an exhaust gas/air mixture flow therethrough;
• an annular orifice arranged downstream of the outflow cross section in the dilution tunnel;
• and
• a flow deflection device arranged upstream of the annular orifice and downstream of the outflow cross section, the flow deflection device being configured to deflect the exhaust gas/air mixture so that a flow of the exhaust gas/air mixture departs from the center axis of the dilution tunnel immediately downstream of the flow deflection device in an axially symmetrical manner.