Patent ID: 8873052

Claim:
A method for determining the quality of measuring results of a scattered light meter, which is provided for measuring particle concentration in motor vehicle exhaust gases, and has at least one scattered light measuring chamber, at least one light source and at least one light sensor, the method comprising: A) in a reference state of the scattered light meter: A1) measuring and storing a first scattered light sensor signal in a first specified operating state of the scattered light meter; A2) measuring and storing a second scattered light sensor signal in a second specified operating state of the scattered light meter; A3) ascertaining and storing a reference signal difference between the second scattered light sensor signal and the first scattered light sensor signal; B) in a used state of the scattered light meter: B1) measuring and storing a third scattered light sensor signal in the first specified operating state of the scattered light meter; B2) measuring and storing a fourth scattered light sensor signal in the second specified operating state of the scattered light meter; B3) ascertaining and storing a signal difference between the second scattered light sensor signal and the first scattered light sensor signal; and C) comparing the signal difference in the used state to the reference signal difference picked up in the reference state.