Method for detecting particles or aerosol in a flowing fluid, computer program, as well as electrical memory medium

A method for detecting particles or aerosol in a flowing fluid, using laser-induced incandescence, the method comprising the following steps:

• a. focusing a laser light originating from a laser in a spot;
• b. conducting the fluid which includes particles or aerosol through the spot;
• c. detecting a thermal radiation originating from the spot using a detector;
• and
• d. evaluating a variable which is provided by the detector and characterizes the detected thermal radiation within time intervals, a duration of the time intervals being dependent on a velocity of the fluid.

An electrical memory medium, for an evaluation unit for use in an exhaust gas system of an internal combustion engine, on which is stored a computer program for detecting particles or aerosol in a flowing fluid, using laser-induced incandescence, the computer program, when executed by the evaluation unit, causing the evaluation unit to perform the following steps:

• a. focusing a laser light originating from a laser in a spot;
• b. conducting the fluid which includes particles or aerosol through the spot;
• c. detecting a thermal radiation originating from the spot using a detector;
• and
• d. evaluating a variable which is provided by the detector and characterizes the detected thermal radiation within time intervals, a duration of the time intervals being dependent on a velocity of the fluid.

A state machine in the form of an ASIC, the ASIC being configured to detect particles or aerosol in a flowing fluid, using laser-induced incandescence, the state machine being configured to:

• a. focus a laser light originating from a laser in a spot;
• b. conduct the fluid which includes particles or aerosol through the spot;
• c. detect a thermal radiation originating from the spot using a detector;
• and
• d. evaluate a variable which is provided by the detector and characterizes the detected thermal radiation within time intervals, a duration of the time intervals being dependent on a velocity of the fluid.