Exhaust gas purification apparatus

Abstract

The present invention relates to an exhaust gas purification apparatus which has an enhanced property of purifying exhaust gas from an internal combustion engine for vehicles, and which is configured to decrease the exhaust gas pressure of the engine. The exhaust gas purification apparatus includes an engine head block, where exhaust pipes combine, has a side on which an exhaust outlet is formed, a first catalytic converter that holds a first catalyst and that is to be coupled to a side of the engine head block, a second catalytic converter that holds a second catalyst and that is coupled to a rear of the first catalytic converter, an exhaust pipe that couples the engine head block to the first catalytic converter. Moreover, the first and second catalysts withstand a temperature equal to / more than 800° C.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of Japanese Patent Application 2006-102545 filed on Apr. 3, 2006, the disclosure of which is incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] Generally, the present invention relates to exhaust gas purification apparatuses. More specifically, the present invention relates to an exhaust gas purification apparatus which has an enhanced property of purifying exhaust gas from an internal combustion engine for vehicles, and which is configured to decrease the exhaust gas pressure of the engine. [0004] 2. Description of the Related Art [0005] First, with reference to FIG. 6, a description will be given below, of a process for purifying exhaust gas from an engine 100b for a commercial vehicle X. [0006] The engine 100b discharges exhaust gas through cylinders within a cylinder block 101. Subsequently, the exhaust gas flows through an engine head block 102 a...

AI Technical Summary

Benefits of technology

[0017] In the above exhaust gas purification apparatus, the exhaust gas fed to the first catalytic converter is relatively hot. Therefore, the catalytic converter operates at relatively high temperatures. As a result, it is possible to enhance the property of purifying the exhaust gas, as well as to reduce the number of the cells, and decrease the amount of the expensive noble metal. This enables the exhaust resistance of the engine to be lowered.

[0019] In the above exhaust gas purification apparatus, the density of the noble metal increases. This enables the purification property to be further enhanced.

[0021] In the above exhaust gas purification apparatus, the exhaust gas diffuses widely over the cells of the catalyst in each catalytic converter, thereby enlarging the area where the exhaust gas comes into contact with the wash coat layer. This enables the purification property to be still further enhanced.

Problems solved by technology

However, when the density of the cells in a catalyst increases for the above reason, the exhaust gas resistance of the catalyst is prone to be high.

This may cause the rise in the pressure of the exhaust gas, which lowers the output power of the engine.

In addition, an amount of noble metal in a catalyst may increase, thus leading to high manufacturing costs for vehicles.

Meanwhile, the property of removing NOx is not improved significantly (as will be described in detail in this specification).

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