| 摘要 |
PURPOSE:To provide an exhaust emission control device for controlling the exhaust emission to be discharged at the time of start of an engine by using an absorbent which has a high adsorption capacity, and has adsorpability/ desorpability at a higher temperature, and also which selectively purifies the hydrocarbon(HC) of high OFP or the like. CONSTITUTION:Zeolite modified by metallic components is used as the principal component of the front part 6a of an adsorbent unit 6, and a catalyst support in which catalyst components making a principal component of noble metal and oxygen donator are supported by the rear part 6b of the adsorbent unit 6; and this adsorbent unit 6 is installed downstream of a three way catalyst 3. When the temperature of the adsorbent unit 6 rises and reaches a prescribed temperature, secondary air is introduced through a line 5 between the three way catalyst 3 and the adsorbent unit 6, thereby the exhaust gas is purified. Since the HC adsorbent in the exhaust gas has a high adsorptive capacity to HC which has a high ozone producing capacity, and the HC amount to be adsorbed or desorbed at a temperature of 300 deg.C or less of the exhaust gas to the total adsorbing amount is 50% or less, most of the desorbed HC is discharged in an oxidized and pollution-free condition. |
