| 摘要 |
PROBLEM TO BE SOLVED: To permit a wide range of load control and to minimize worsening of emission. SOLUTION: When the target air quantity is less than the specified value L1, intake valve closing timing IVC is controlled according to the target air quantity (S4). At this time, the overlap O/L of an exhaust valve and an intake valve is set to the small side set value (S5), throttle opening TVO is controlled to obtain constant negative pressure (S6), and fuel injection is set to exhaust stroke injection (S7). When the target air quantity is the specified value L1 or more, and less than the second specified value L2, the intake valve closing timing IVC is fixed to an optimum point (S8), and the throttle opening TVO is controlled according to the target air quantity (S10). When the target air quantity is the specified value L2 or more, the throttle opening TVO is fixed to full opening (S14), and the overlap O/L is controlled to the large side to obtain a scavenging effect (S12). Fuel injection is set to intake stroke injection (S15).
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