MONITORING DEVICE OF FUEL INJECTION AMOUNT CONTROL DEVICE

PROBLEM TO BE SOLVED: To suppress the occurrence of erroneous determination that an abnormality occurs in a calculation part after the finish of a start of an engine.SOLUTION: A microcomputer 21 determines that an abnormality occurs in a calculation function related to the calculation or the like of an injection amount command value on the basis of the fact that the injection amount command value which is calculated at defined time intervals is deviated to an increase side with respect to a monitoring injection amount which is calculated at the same defined time intervals. The microcomputer 21 calculates a start-time injection amount on the basis of a cooling water temperature of an engine so that the amount becomes smaller than that in the case that the cooling water temperature is low when the cooling water temperature is high, and uses the start-time injection amount as an injection amount command value immediately after the finish of a start of the engine. Furthermore, the microcomputer 21 uses, as a monitoring start-time injection amount which is set as the monitoring injection amount immediately after the finish of the start of the engine, smaller one out of a start-time injection amount which is calculated this time and a monitoring start-time injection amount which is calculated last time.SELECTED DRAWING: Figure 1 【課題】エンジンの始動完了後において、算出部に異常が発生しているとの誤判断が生じることを抑制する。【解決手段】マイクロコンピュータ２１は、定められた時間間隔で算出される噴射量指令値が、同じく定められた時間間隔で算出される監視用噴射量に対し、増大側に乖離したことに基づき、噴射量指令値の算出等にかかわる算出機能に異常が生じたと判断する。マイクロコンピュータ２１は、エンジンの冷却水温に基づき始動時噴射量を同冷却水温が高いときには低いときよりも小さくなるように算出し、エンジンの始動完了直後には始動時噴射量を噴射量指令値として用いる。また、マイクロコンピュータ２１は、エンジンの始動完了直後に上記監視用噴射量とされる監視用始動時噴射量として、今回算出された始動時噴射量と前回算出された監視用始動時噴射量との小さい方を用いる。【選択図】図１