TH97168A - Exhaust devices and riding vehicles - Google Patents

Abstract

In constructing a highly efficient exhaust device, the exhaust device (10) will include an upstream catalytic converter (21) where the more concentrated exhaust gases in the stoichiometric mixture flow from the engine, a secondary air supply (23) where secondary air is added to the exhaust gases, and a downstream catalytic converter (22) built at the end of the secondary air supply (23). The highest concentration of the catalytic converter components of the upstream catalytic converter (21) is the same as the highest concentration of the catalytic converter components of the downstream catalytic converter (22). The composition of the initial catalyst material (21) is the same as that of the highest concentration of the catalytic material components of the final catalyst (22).

Claims (11)

1. Exhaust catalytic converter components: A primary catalytic converter where the more concentrated exhaust gases (relatively ratio) flow from the engine; a mid-stage catalytic converter built into the exhaust passage; a secondary air intake pipe where secondary air is added to the exhaust gases flowing through the exhaust passage from the primary catalytic converter; and a secondary catalytic converter built into the exhaust passage at the end of the exhaust passage, where secondary air is added to the exhaust gases through the secondary air intake pipe. The component composition of the primary catalytic converter is identical to that of the secondary catalytic converter. 2. Exhaust catalytic converter according to claim 1, where each upstream catalytic converter and the downstream catalytic converter contain palladium as the component with the highest concentration. 3. Exhaust device according to claim 2, where the palladium content in the catalytic material of the downstream catalytic converter is higher than the palladium content in the catalytic material of the upstream catalytic converter. 4. Exhaust devices under claim 2, where the rhodium content in the upstream catalytic converter material is higher than the rhodium content in the downstream catalytic converter material. 5. An exhaust device as described in any of the claims 1 through 4, whereby the exhaust passage is extended in at least one direction from a position where the upstream catalytic converter is placed to a position where the downstream catalytic converter is placed. 6. The exhaust system consists of an exhaust pipe, a pre-catalytic converter built into the exhaust pipe, a terminal catalytic converter built into the exhaust pipe at the end of the pre-catalytic converter and containing palladium as the highest concentration of catalytic material in the terminal catalytic converter, and a secondary air supply pipe connected to the exhaust pipe at the position between the pre-catalytic converter and the terminal catalytic converter. The exhaust pipe extends in at least one direction from one position where the pre-catalytic converter is built to one position where the terminal catalytic converter is positioned. 7. Exhaust device according to claim 6, where the catalytic converter material of the primary catalytic converter shall consist of rhodium. 8. Exhaust devices pursuant to claim 7, where the rhodium content in the upstream catalytic converter material is higher than the rhodium content in the downstream catalytic converter material. 9. An exhaust device pursuant to any of the claims in Reputations 6 through 8 shall also include a silencer for the purpose of being placed at the rear end of the exhaust pipe, where the internal space of the silencer shall be divided into numerous expansion chambers into which the exhaust gases shall flow sequentially. These expansion chambers shall include a primary expansion chamber, into which the rear end of the exhaust pipe shall be positioned, and at least one initial and final catalytic converter may be placed in this primary expansion chamber. 10. The exhaust device under claim 7 also includes a silencer for placement at the rear of the exhaust pipe, where the internal space of the silencer is divided into numerous expansion chambers into which the exhaust gases flow sequentially. These expansion chambers include a main expansion chamber, which is positioned at the rear end of the exhaust pipe, and the initial catalytic converter is placed in one of the many expansion chambers, with one expansion chamber built at a location towards the rear of the main expansion chamber. 11. Which of the following types of riding vehicles are equipped with exhaust devices as specified in claims 1 through 10?