EXHAUST GAS PURIFYING DEVICE AND EXHAUST GAS PURIFYING METHOD IN INTERNAL COMBUSTION ENGINE

摘要

A collector is provided in each of a pair of exhaust gas passages parallelly extending from an internal combustion engine. Each collector collects black smoke particles (unclean substances) contained in an exhaust gas. One of a pair of pressure difference detectors detects a first pressure difference between the upstream side and downstream side in one of the collectors, and the other pressure difference detector detects a second pressure difference between the upstream side and downstream side in the other collector. Immediately after the completion of recovery treatment for removing black smoke particles in each of the collectors, a control computer estimates an exhaust gas flow rate in each of the exhaust gas passages based on the first pressure difference and second pressure difference.