Exhaust pipe
AssigneeToyota Jidosha Kabushiki Kaisha
InventorsTakashi Sasajima, Hideo Yamashita, Daisaku Sawada
Life of this patent
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Abstract
An exhaust pipe through which an exhaust port of an internal combustion engine and a catalyst for purifying an exhaust gas of the internal combustion engine are connected to each other includes a porous portion that is provided on at least a part of an inner peripheral face of the exhaust pipe. A thermal conductivity that the porous portion exhibits in a high temperature state where a temperature of the exhaust gas is as high as it is required to radiate a heat of the exhaust gas through the exhaust pipe is at least ten times higher than a thermal conductivity that the porous portion exhibits in a low temperature state where the temperature of the exhaust gas is as low as it is required to warm the catalyst up.
Claims12
An exhaust pipe through which an exhaust port of an internal combustion engine and a catalyst for purifying an exhaust gas of the internal combustion engine are connected to each other, comprising:
- a porous portion that is provided on at least a part of an inner peripheral face of the exhaust pipe, wherein
- a thermal conductivity that the porous portion exhibits in a high temperature state where a temperature of the exhaust gas is as high as it is required to radiate a heat of the exhaust gas through the exhaust pipe is at least ten times higher than a thermal conductivity that the porous portion exhibits in a low temperature state where the temperature of the exhaust gas is as low as it is required to warm the catalyst up.
An exhaust pipe through which an exhaust port of an internal combustion engine and a catalyst for purifying an exhaust gas of the internal combustion engine are connected to each other, comprising:
- a porous portion that is provided on at least a part of an inner peripheral face of the exhaust pipe, wherein
- a thermal conductivity that the porous portion exhibits when a temperature of the catalyst is close to an upper limit temperature of the catalyst is at least ten times higher than a thermal conductivity that the porous portion exhibits when the temperature of the catalyst is lower than an activation temperature of the catalyst.
Dependencies are inferred from the claim text.