EXHAUST SYSTEM TEMPERATURE ESTIMATION DEVICE FOR ENGINE

To provide an exhaust system temperature estimation device for an engine capable of highly accurately estimating a temperature of an exhaust system even when an EGR system is operated.SOLUTION: In regard to a temperature of an exhaust system in a steady operation state of an engine (1) stored beforehand, data in each operating condition during EGR non-operation and data in a predetermined EGR rate condition are provided. In response to a change of an EGR rate, an exhaust system gas temperature baseline value during steady combustion is calculated from data in the EGR rate condition including EGR non-operation time, and an exhaust system temperature baseline value during the steady combustion is corrected by using a correction amount corresponding to an ignition retard amount corrected according to the EGR rate so as to calculate a temperature estimation value of the exhaust system during the steady combustion.SELECTED DRAWING: Figure 3 【課題】ＥＧＲシステムが作動したときでも、高精度に排気系温度を推定することができるエンジンの排気系温度推定装置を提供する。【解決手段】予め記憶したエンジン（１）の定常運転状態における排気系の温度を、運転条件毎にＥＧＲ非作動時のデータと、予め定められたＥＧＲ率条件のデータとを備えており、ＥＧＲ率の変化に応じて、ＥＧＲ非作動時を含むＥＧＲ率条件でのデータから定常燃焼時の排気系ガス温度基本値を演算し、定常燃焼時の排気系の温度基本値を、ＥＧＲ率に応じて補正した点火リタード量による補正量により補正して、定常燃焼時の排気系の温度推定値を算出する。【選択図】図３