| 摘要 |
PROBLEM TO BE SOLVED: To highly precisely set an EGR start timing to such timing as forming no freeze-up in an injection port of a fuel injection valve. SOLUTION: An estimate tip temperature TINJ of the fuel injection valve is calculated using an intake air temperature and a cooling water temperature in starting (step 101). In this case, the initial value of the estimate tip temperature TINJ is set to the air intake temperature in starting, and after starting, an injection port temperature obtained by multiplying the cooling water temperature by a conversion constant is moderated so as to find the final estimate tip temperature TINJ. Then, the EGR start timing temperature TEGR is calculated from a map according to the intake air temperature in starting (step 102) and whether the estimate injection port temperature TINJ is the EGR start temperature TEGR or more or not is judged (step 103). If TINJ<TEGR, the EGR is held in a stopped state (step 104), and when it is judged TINJ>=TEGR and if EGR execution conditions are held, EGR is started (steps 105, 106).
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