Aerosol generating device with puff detection

Abstract

An aerosol-generating device for generating an aerosol from an aerosol-forming substrate is provided, the device including: a device housing defining a chamber configured to receive the substrate; an airflow channel extending from an air inlet in the device housing and through, or in fluid communication with, the chamber; and a puff sensor assembly including a heat transfer element and a temperature sensor in contact with the heat transfer element, a first portion of the airflow channel being at least partially defined by an airflow channel wall and a second portion of the airflow channel being at least partially defined by the heat transfer element, the second portion being adjacent to the first portion and outside of the chamber, and at least one of thermal conductivity or thermal diffusivity of the heat transfer element being greater than a respective thermal conductivity or thermal diffusivity of the airflow channel wall.

1 .- 16 . (canceled) 
     
     
         17 . An aerosol-generating device for generating an aerosol from an aerosol-forming substrate, the aerosol-generating device comprising:
 a device housing defining a chamber configured to receive the aerosol-forming substrate;   an airflow channel extending from an air inlet in the device housing and through, or in fluid communication with, the chamber; and   a puff sensor assembly comprising a heat transfer element and a temperature sensor in contact with the heat transfer element,   wherein a first portion of the airflow channel is at least partially defined by an airflow channel wall and a second portion of the airflow channel is at least partially defined by the heat transfer element, the second portion of the airflow channel being adjacent to the first portion and outside of the chamber, and   wherein at least one of thermal conductivity or thermal diffusivity of the heat transfer element is greater than a respective thermal conductivity or thermal diffusivity of the airflow channel wall.   
     
     
         18 . The aerosol-generating device according to  claim 17 , further comprising a heater assembly configured to heat the aerosol-forming substrate received in the chamber. 
     
     
         19 . The aerosol-generating device according to  claim 17 , wherein the heat transfer element has a thermal conductivity of between 100 Watts per metre-Kelvin and 300 Watts per metre-Kelvin. 
     
     
         20 . The aerosol-generating device according to  claim 17 , wherein the heat transfer element has a thermal diffusivity of greater than 50 millimetres squared per second. 
     
     
         21 . The aerosol-generating device according to  claim 18 ,
 wherein the heater assembly comprises a heating element, and   wherein, in use and between puffs, the heat transfer element is heated by the heating element to a temperature of at least 5, 10, 20, 40, or 80 degrees centigrade above ambient temperature.   
     
     
         22 . The aerosol-generating device according to  claim 21 , wherein a distance between the heat transfer element and heating element is less than 50 millimetres. 
     
     
         23 . The aerosol-generating device according to  claim 17 , wherein a thickness of the heat transfer element is between 0.1 millimetres and 0.5 millimetres. 
     
     
         24 . The aerosol-generating device according to  claim 17 , wherein a surface area of a portion of the heat transfer element partially defining the airflow path is at least 1, 2, 5, 10, or 20 millimetres squared. 
     
     
         25 . The aerosol-generating device according to  claim 17 , wherein the heat transfer element is press-fit into the airflow channel wall. 
     
     
         26 . The aerosol-generating device according to  claim 17 , wherein the airflow channel wall comprises an opening adjacent to the heat transfer element. 
     
     
         27 . The aerosol-generating device according to  claim 26 , wherein the temperature sensor is received through the opening such that the temperature sensor is in contact with the heat transfer element. 
     
     
         28 . The aerosol-generating device according to  claim 17 , wherein the heat transfer element is tubular. 
     
     
         29 . The aerosol-generating device according to  claim 17 ,
 wherein a first surface of the heat transfer element at least partially defines the second portion of the airflow channel and the temperature sensor is in contact with a second surface of the heat transfer element, and   wherein the first surface is different to the second surface.   
     
     
         30 . The aerosol-generating device according to  claim 17 ,
 further comprising a heater assembly,   wherein the second portion of the airflow channel is upstream of the heater assembly.   
     
     
         31 . An aerosol-generating system comprising an aerosol-generating device according to  claim 17  and an aerosol-generating article comprising an aerosol-forming substrate, the aerosol-generating article being receivable in the chamber. 
     
     
         32 . A method of detecting a user puffing on the aerosol-generating system according to  claim 31 , the method comprising:
 receiving an aerosol-forming substrate in a chamber of the aerosol-generating device;   heating the received aerosol-forming substrate;   heating the heat transfer element;   receiving signals from the temperature sensor at a controller of the aerosol-generating device to repeatedly determine a measured temperature of the temperature sensor; and   detecting a user puff based on a drop in the measured temperature.