Patent ID: 8505276

Claim:
A particulate matter measurement device comprising: a mixer that is connected to an exhaust pipe of an automobile and connected to a dilution gas introducing inlet and that mixes an exhaust gas from an engine of the automobile with a dilution gas so as to dilute the exhaust gas, a particulate matter sensor into which a part of the diluted exhaust gas diluted by the mixer is introduced and that continuously measures a mass-related value indirectly indicating a mass of particulate matters contained in the diluted exhaust gas, a collection filter through which the remainder of the diluted exhaust gas passes and that collects the particulate matters contained in the remainder of the diluted exhaust gas, a valve that adjusts a flow rate of the dilution gas introduced into the mixer, a mass flow controller that adjusts a flow rate of the diluted exhaust gas passing, the collection filter, and at least one controller programmed to keep a flow rate of the diluted exhaust gas passing the collection filter at a constant value by controlling the mass flow controller, to secure a necessary flow rate of the diluted exhaust gas introduced into the particulate matter sensor by controlling the valve, to calculate a correlation between a mass measurement value of the particulate matters collected by the collection filter during a predetermined period while the engine is in operation and a time integrated value of the mass-related value measurement data during the predetermined period, as being a time series change data of the mass-related value measured by the particulate matter sensor, and to convert the mass-related value measurement data to the time series change data of the mass of the particulate matters based on the correlation.