| 摘要 |
At time t1, a fuel cutoff during deceleration is performed. The oxygen storage amount (rOS), which increases after the fuel cutoff, is estimated on the basis of the exhaust air-fuel ratio and the intake air amount. At the time (t2) when the oxygen storage amount (rOS) has reached a threshold, the target compression ratio (tCR) is corrected to a value lower than the basic target compression ratio (tCR). Although a fuel recovery is performed at time t4, the combustion temperature decreases due to the reduced mechanical compression ratio and, hence, NOx generation in the combustion chambers is inhibited. Consequently, NOx emission is inhibited from increasing even when the oxygen storage amount (rOS) of the exhaust gas purification catalyst (4) is excessively large. |
