JP-2026074699-A - Electrically heated catalyst device

Abstract

[Challenge] To achieve both condensation countermeasures and flexibility in installation. [Solution] The catalyst device comprises a cylindrical base material 26, a first electrode, and a second electrode. The first electrode has a first electrode portion fixed to the surface of the base material 26, and a first connection portion 211c that extends in a direction away from the outer circumferential surface of the base material 26 and is connected to an external power source to supply power to the first electrode portion. The second electrode has a second electrode portion fixed to the surface of the base material 26 at a location spaced apart from the first electrode portion in the circumferential direction of the base material 26, and a second connection portion 212c that extends in a direction away from the outer circumferential surface of the base material 26 and is connected to an external power source to supply power to the second electrode portion. The first connection portion 211c and the second connection portion 212c are arranged side by side, spaced apart along the direction in which the central axis C of the base material 26 extends, and are positioned at the uppermost position of the base material 26 when mounted on a vehicle. [Selection Diagram] Figure 3

Inventors

• 沖 俊典

Assignees

• トヨタ自動車株式会社

Dates

Publication Date

20260507

Application Date

20241021

Claims (1)

1. An electrically heated catalytic converter installed in the exhaust pipe of an internal combustion engine mounted on a vehicle, A cylindrical substrate supporting a catalyst, It comprises a first electrode and a second electrode that conduct current on the substrate, The first electrode comprises a first electrode portion fixed to the surface of the substrate and a first connection portion extending in a direction away from the outer peripheral surface of the substrate and connected to an external power source to supply power to the first electrode portion. The second electrode has a second electrode portion fixed to the surface of the substrate at a location spaced apart from the first electrode portion in the circumferential direction of the substrate, and a second connection portion extending in a direction away from the outer surface of the substrate and connected to the external power supply to supply power to the second electrode portion. The first and second connecting portions are arranged to be spaced apart along the direction in which the central axis of the base material extends, and are positioned at the uppermost position of the base material when mounted on a vehicle.

Description

This invention relates to an electrically heated catalyst device. The electrically heated catalyst device described in Patent Document 1 comprises a cylindrical substrate supporting a catalyst, and a first electrode and a second electrode provided on the outer surface of the substrate. In the vertical direction when installed in an exhaust pipe, the first and second electrodes are located above the central axis on the outer surface of the substrate. This configuration prevents condensed water generated inside the exhaust pipe where the electrically heated catalyst device is installed from reaching the electrodes. Japanese Patent Publication No. 2017-129085 Figure 1 is a radial cross-sectional view of a catalyst device according to one embodiment.Figure 2 is a side view of the substrate and the first electrode of the catalyst device, along the direction in which the central axis of the substrate extends.Figure 3 is a perspective view showing the substrate and its surrounding components. Below, an embodiment of an electrically heated catalyst device will be described with reference to Figures 1 to 3. <About the configuration of the catalytic converter> This section describes an electrically heated catalytic converter 200 installed in the exhaust pipe of an internal combustion engine mounted on a vehicle. In the following, the upstream side in the direction of exhaust flow will be referred to as the "upstream side," and the downstream side in the direction of exhaust flow will be referred to as the "downstream side." As shown in Figure 1, the catalytic converter 200 comprises a cylindrical substrate 26 on which a catalyst for purifying exhaust gas is supported. The substrate 26 has a honeycomb structure with multiple passages extending in the direction of exhaust gas flow, and for example, a three-way catalyst is supported on it. The base material 26 is housed in the case 20. The case 20 is a double cylinder made of metal, such as stainless steel, and consists of a cylindrical inner tube 24 that houses the base material 26 inside, and a cylindrical outer tube 23 that is spaced apart outside the inner tube 24. A first mat 28 is interposed between the base material 26 and the inner tube 24. The first mat 28 is an insulator and is formed from inorganic fibers, for example, primarily composed of alumina. The first mat 28 is interposed between the base material 26 and the inner tube 24 in a compressed state. Therefore, the base material 26 is held within the inner tube 24 by the restoring force of the compressed first mat 28. A second mat 29 is interposed in the space between the outer tube 23 and the inner tube 24. The second mat 29 is an insulator and is formed from inorganic fibers, for example, primarily composed of alumina. The second mat 29 is interposed between the outer tube 23 and the inner tube 24 in a compressed state. Therefore, the inner tube 24 is held within the outer tube 23 by the restoring force of the compressed second mat 29. The base material 26 is formed of a material that generates heat when electricity is passed through it. For example, silicon carbide can be used as such a material. A pair of surface electrodes 30 are provided on the outer circumferential surface of the substrate 26, facing each other in the radial direction of the substrate 26. The surface electrodes 30 have a rectangular planar shape and extend in the axial direction of the substrate 26. The surface electrodes 30 are a porous film formed on the surface of the substrate 26 by thermal spraying, and are made of a metal material with excellent oxidation resistance at high temperatures, such as a NiCr alloy. The catalyst device 200 includes a first electrode 211 and a second electrode 212 that supply current to the substrate 26. The first electrode 211 and the second electrode 212 are made of a metallic material, such as stainless steel. The first electrode 211 is the positive electrode, and the second electrode 212 is the negative electrode. By applying a voltage from an external power source 400 between the first electrode 211 and the second electrode 212, current flows through the substrate 26. When current flows through the substrate 26, it is heated by generating heat due to electrical resistance. The first electrode 211 comprises a first electrode portion 211a, a first lead wire 211b, and a first connection portion 211c. The first electrode portion 211a is a comb-shaped thin plate and is fixed to the surface of one of the pair of surface electrodes 30. The first lead wire 211b is a flat, thin plate that runs along the surface of the base material 26 and extends to the uppermost position in the vertical direction above the base material 26 in the circumferential direction, and is connected to the first electrode portion 211a. More specifically, the first lead wire 211b and the first electrode portion 211a are integrally formed. The first connection portion 211c extends in a direction away from the outer circumferential su