TH48779B - Exhaust purification system for internal combustion engines - Google Patents

Abstract

DC60 (21/12/53) [Problem to be solved] To provide an exhaust gas purification system for an internal combustion engine in which both NOx reduction and CO and THC oxidation in the exhaust can be effectively achieved using three catalysts. [Solution] The first catalyst (30) is placed closer to the exhaust source than the second catalyst (40). By doing so, secondary air flowing upstream from the secondary air intake (60) in the exhaust pipe (20) can be blocked at the second catalyst (40). As a result, NOx can be adequately reduced at the first catalyst (30), in addition to NOx reduction at the second catalyst (40). Furthermore, a third catalyst (50) is placed closer to the exhaust source. The second catalyst 40 oxidizes CO and THC at the third catalyst 50 [Optional diagram] Figure 1 [Problem to be solved] To provide an exhaust gas purification system for an internal combustion engine in which both NOx reduction and CO and THC oxidation present in the exhaust can be effectively accomplished using three catalysts. [Solution] The first catalyst 30 is placed closer to the source than the second catalyst 40. By doing so, secondary air flowing upstream from the secondary air intake 60 in the exhaust 20 can be blocked at the second catalyst 40. As a result, NOx can be adequately reduced at the first catalyst 30 in addition to NOx reduction at the second catalyst 40. Furthermore, the third catalyst 50 is placed closer to the end than the second catalyst 40. In the second reaction, 40 CO and THC are oxidized at the third catalyst, 50 [selected diagram]. Figure 1.

Claims (2)

Revised 24/02/58 1. Exhaust purification system for internal combustion engines, consisting of: Exhaust manifold for releasing exhaust gases from the internal combustion engine; First catalytic converter, located midway in the exhaust manifold, for reducing at least NOx present in the exhaust; Second catalytic converter, located midway in the exhaust manifold, closer to the end than the first, for reducing at least NOx present in the exhaust components flowing from the first; Third catalytic converter, located midway in the exhaust manifold, closer to the end than the second, and constructed with a different material than the first and second, for oxidizing at least CO and THC in the exhaust components present in the exhaust flowing from the second; and Secondary air intake pipe, located in the exhaust manifold between the second and third catalytic converters, for introducing secondary air into the exhaust manifold; with another secondary air intake pipe located between the first and second catalytic converters in the exhaust manifold. 1. For introducing secondary air into the exhaust manifold. 2. An exhaust purification system for internal combustion engines as per claim 1, where another secondary air intake pipe has a flow control valve to regulate the flow of secondary air introduced from the intake pipe into the exhaust manifold. 1. The exhaust gas purification system for an internal combustion engine consists of: an exhaust manifold for releasing exhaust gases from the internal combustion engine; a first catalytic converter located midway through the exhaust manifold to reduce at least NOx present in the exhaust; a second catalytic converter located midway through the exhaust manifold, closer to the end than the first, to reduce at least NOx present in the exhaust components flowing out of the first; a third catalytic converter located midway through the exhaust manifold, closer to the end than the second, and constructed from a different material than the first and second, to oxidize at least CO and THC in the exhaust components present in the exhaust flowing out of the second; and a secondary air intake located in the exhaust manifold between the second and third catalytic converters to bring secondary air into the exhaust manifold. The exhaust manifold also has another secondary air intake located between the first and second catalytic converters. For introducing secondary air into the exhaust pipe. 2. An exhaust gas purification system for internal combustion engines under claim 1, whereby a secondary air intake pipe has a flow control valve to regulate the flow of secondary air entered from the intake pipe into the exhaust pipe.