Patent ID: 8613192

Claim:
An exhaust gas purifier, comprising: a filter that purifies an exhaust gas arranged in an exhaust path of an engine; an actuation portion hydraulic pump that drives on the basis of a power of the engine; a sensor for detecting a clogging state of the filter; and a forced actuation valve that forcibly increases pressure on a first side of the actuation portion hydraulic pump; wherein the filter is regenerated by increasing an engine load while maintaining an engine rotating speed; wherein the forced actuation valve comprises a pressure control valve and a pilot pressure solenoid valve, the pressure control valve having a back pressure mechanism and being provided between the actuation portion hydraulic pump and an actuation portion hydraulic circuit located at a downstream side of the actuation portion hydraulic pump, the pilot pressure solenoid valve applying a pilot pressure to the back pressure mechanism; and wherein the pressure control valve maintains pressure and flow on said downstream side constant when pressure on said first side is increased, and is controlled by self-pressure of actuation fluid that flows into the back pressure mechanism from the actuation portion hydraulic pump, via the pilot pressure solenoid valve.