Catalyst device
AssigneeToyota Jidosha Kabushiki Kaisha
InventorToshinori OKI
Life of this patent
Estimating the term…
Abstract
A catalyst device includes a heating element that generates heat when energized, a case that accommodates a catalyst support (heating element), an inflow pipe that draws exhaust gas into the case, and a connecting pipe that connects the inflow pipe and the case to each other. The case includes an end portion, which protrudes further in an upstream direction than an end face of the catalyst support. The inflow pipe is disposed inside the case. The catalyst device includes a triple-walled pipe structure, in which the connecting pipe overlaps with the end portion of the case and the inflow pipe in a covering manner.
Claims5
A catalyst device that is disposed in an exhaust passage, the catalyst device comprising:
- a catalyst that purifies exhaust gas;
- a heating element that generates heat when energized and is configured to heat the catalyst;
- a case that is a pipe accommodating the catalyst and the heating element;
- a mat that is an insulating body for fixing the heating element in the case;
- a connecting pipe that is connected to an end portion of the case that is on an upstream side in a gas discharging direction, the gas discharging direction being a direction in which the exhaust gas flows in the exhaust passage;
- and
- an inflow pipe that is connected to an upstream end of the connecting pipe and has a radius smaller than a radius of the case, wherein
- the end portion on the upstream side of the case protrudes further in an upstream direction than an upstream end of the heating element and is an electrically insulating portion,
- a portion in which the inflow pipe and the connecting pipe are connected to each other is a first connection portion,
- a portion in which the connecting pipe and the case are connected to each other is a second connection portion,
- the first connection portion includes:
- a first joint portion in which the connecting pipe is joined to an outer circumferential surface of the inflow pipe;
- and
- a double-walled pipe structure that is located downstream of the first joint portion and in which the connecting pipe covers an insertion end portion of the inflow pipe, and the connecting pipe and the inflow pipe overlap with each other such that the connecting pipe and the inflow pipe are separated from each other in a radial direction,
- the second connection portion includes a second joint portion in which the connecting pipe is joined to an outer circumferential surface of the case,
- the catalyst device further comprises a triple-walled pipe structure between the first connection portion and the second connection portion, and
- the case, the connecting pipe, and the inflow pipe overlap with one another in the triple-walled pipe structure such that
- the inflow pipe is disposed inside the case,
- the inflow pipe and the case are separated from each other in the radial direction, and
- the case and the connecting pipe are separated from each other in the radial direction.
Dependencies are inferred from the claim text.