Abstract: Provided is a piston temperature state monitoring system for an internal combustion engine and a piston temperature monitoring method for an internal combustion engine which are capable of properly managing a history of a piston temperature. When the number of times of a piston temperature suppression control is counted, if a ratio of a temperature difference which is the difference between a maximum limit temperature and a piston temperature to a margin width which is the difference between the maximum limit temperature and a control start temperature is equal to or less than a count threshold ratio set in advance or calculated, a count output system outputs a count signal.

Abstract: Provided is a piston temperature state monitoring system for an internal combustion engine and a piston temperature monitoring method for an internal combustion engine which are capable of properly managing a history of a piston temperature. When the number of times of a piston temperature suppression control is counted, if a ratio of a temperature difference which is the difference between a maximum limit temperature and a piston temperature to a margin width which is the difference between the maximum limit temperature and a control start temperature is equal to or less than a count threshold ratio set in advance or calculated, a count output system outputs a count signal.

Abstract: An exhaust emission purification system having a controller performing exhaust temperature rise control including multistage delay injection control for raising the exhaust temperature, if the exhaust gas temperature is lower than a predetermined judgment temperature, and performing particulate matter combustion removal control including post injection control, if the exhaust gas temperature becomes equal to or higher than the predetermined judgment temperature, when forced regeneration of a diesel particulate filter is carried out. The multistage delay injection control is forbidden when an idle operation state of an internal combustion engine occurs for a predetermined judgment time and a power take-off device is operating.

Abstract: An exhaust emission purification system including a controller performing exhaust temperature rise control executing multistage delay injection control for raising the exhaust temperature, if the exhaust gas temperature is lower than a predetermined judgment temperature, and performing particulate matter combustion removal control executing post injection control, if the exhaust gas temperature becomes equal to or higher than the predetermined judgment temperature, when forced regeneration of a diesel particulate filter is carried out. Multistage delay injection control is forbidden when an idle operation state of an internal combustion engine is sustained for a predetermined judgment time and a power take-off is in operating state. The diesel particulate filter is thereby kept in a good state in a vehicle equipped for purifying particulate matter in exhaust gas by executing forced regeneration while avoiding variation in engine speed.