| 摘要 |
<p>PURPOSE:To control accurately the flow of exhaust gas by providing an A/F sensor for detecting O2 concentration in the exhaust gas at an outlet of a particulate trap (hereinafter called simply trap) to control the opening of an inlet valve so that the O2 concentration has an optimum value for recombustion. CONSTITUTION:During recombustion on a trap 1, a control means 14 reads O2 concentration in exhaust gas at a trap outlet through an A/F sensor 2 and calculatively controls the opening of an inlet valve 7 of the trap 1 for setting the read value to a prestored set value (value of O2 concentration experimentally obtained and stored in the exhaust gas at the trap outlet during the optimum recombustion). Accordingly, in the low load of an engine having low temperature of exhaust gas in a trap inlet and rich O2 concentration, a small amount of exhaust gas is given and a sufficient O2 amount for recombustion is supplied to avoid the trap cooling. Also, since the O2 concentration in the exhaust gas at the inlet is lean in the high load of the engine, a large amount of exhaust gas is given and the necessary O2 amount is supplied.</p> |
