Aerosol-generating system with pump

An aerosol-generating system, comprising:

• a liquid storage portion configured to hold a liquid aerosol-forming substrate;
• a first tubing segment fluidly coupled to an outlet of the liquid storage portion;
• a micro pump fluidly coupled to the first tubing segment and configured to deliver the liquid aerosol-forming substrate at a flow rate from the liquid storage portion to a chamber adjacent an outlet end of the micro pump;
• a second tubing segment fluidly coupled to the outlet end of the micro pump and configured to deliver the liquid aerosol-forming substrate from the micro pump to the chamber;
• and
• a heating element within the chamber, the heating element defining an internal passage fluidly coupled to the second tubing segment, the heating element configured to directly heat the delivered liquid aerosol-forming substrate within the internal passage, a temperature of the heating element controlled based on at least a preheat duration parameter and adjusted in accordance with the flow rate, the micro pump configured to be activated for at least an individual pump cycle in response to the temperature reaching an operating temperature within a preheat duration based on the preheat duration parameter.