Patent ID: 7171802

Claim:
An engine system comprising: a diesel engine; an exhaust passage connected to the engine; a diesel particulate matter (DPM) filter provided on the exhaust passage, which traps DPM contained in an exhaust gas of the engine; a temperature adjusting device coupled to the engine, the temperature adjusting device adjusting an exhaust gas temperature of the engine; and a controller coupled to the temperature adjusting device, the controller functioning to: determine a filter differential pressure, which is a difference between an inlet pressure and an outlet pressure of the DPM filter; switch between a first trapped DPM amount calculation process for estimating the trapped DPM amount after complete regeneration, in which all of the DPM trapped in the DPM filter is burned, and a second trapped DPM amount calculation process for estimating the trapped DPM amount after a part of the DPM trapped in the DPM filter has been burned away, in accordance with a regeneration condition of the DPM filter; estimate the trapped DPM amount in the DPM filter on the basis of the filter differential pressure using one of the first and second trapped DPM amount calculation processes; and control the temperature adjusting device to raise the exhaust gas temperature when the estimated trapped DPM amount becomes greater than a predetermined value to regenerate the DPM filter by burning the DPM trapped in the DPM filter, wherein the first and second trapped DPM amount calculation processes are processes to calculate the trapped DPM amount by referring to a first trapped DPM amount map and a second trapped DPM amount map respectively, and in the first and second trapped DPM amount maps, the trapped DPM amount and the filter differential pressure are defined in a substantially linear relationship and when the filter differential pressure is equal, a value obtained by referring to the second trapped DPM amount map is greater than a value obtained by referring to the first trapped DPM amount map.