JPS638807Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an exhaust particulate trap installed in an exhaust system as a device for collecting and regenerating particulates discharged from an internal combustion engine, particularly a compression ignition engine (diesel engine). In particular, it relates to a trap equipped with an electric heater as an auxiliary means for regeneration.

At the time of regeneration, part of the mainly carbon-based particulate collected in a trap material such as a foam filter is ignited by an electric heater, and thereafter the trap material is regenerated by self-combustion of the particulate. The electric heater is closely supported on the upstream end face of the trap material in order to reliably ignite the particulate, but it consumes a considerable amount of power to ignite the particulate to the extent that it completely self-combusts. The reason for this is that the element portion of the electric heater is cooled by the flow of exhaust gas, and that the amount of particulate deposited near the heater element necessary for ignition is small.

The purpose of this invention is to solve these problems, and in particular, to minimize the cooling loss of the electric heater element due to the flow of exhaust gas, and to reduce the amount of particulate deposits near the electric heater element necessary for ignition. To provide an exhaust particulate trap capable of reliably igniting particulate with low power consumption.

In order to achieve this purpose, the present invention provides a main trap material that is capable of collecting exhaust particulates and has a front surface inclined with respect to the flow direction of exhaust gas, inside a trap container provided in the exhaust passage of the engine. , an electric heater is arranged on the inclined front surface of the main trap material, an auxiliary trap material having an inclined rear surface corresponding to the inclined front surface is provided on the front side of the electric heater, and the electric heater is sandwiched between the main trap material and the auxiliary trap material. It is characterized by being configured as follows. By providing the auxiliary trap material in the front part of the electric heater, the flow of exhaust gas impinging on the element of the electric heater is weakened, and the cooling loss of the electric heater element due to the flow of exhaust gas can be reduced. Furthermore, when the exhaust gas exits the auxiliary trap material, the gas flow stagnates, and the amount of particulate deposits near the electric heater element increases, improving ignition. Further, since the arrangement region of the electric heater is inclined, the arrangement area becomes large, and the density of the electric element can be increased in the flow direction of exhaust gas, so that a large amount of thermal energy can be taken.

The inclined surfaces of the main trap material and the auxiliary trap material are preferably inclined so that the lower side is on the upstream side and the upper side is on the downstream side with respect to the flow direction of the exhaust gas. As a result, the fire ignited by the lower electric heater element rises during regeneration, so that the auxiliary trap material can be regenerated effectively.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a sectional view of an exhaust particulate trap according to the present invention. A cylindrical trap container 1 is provided in an exhaust pipe line downstream of an exhaust manifold (not shown) of a diesel engine, and a main collection material (trap material) 2 is disposed inside the trap container 1. As the main trap material 2, a known foamed ceramic such as a foam filter or a similar material can be used. That is, the main trap material has a three-dimensional mesh structure, and when the exhaust gas is discharged in the direction of arrow P in FIG. It is now possible to collect them in between. The front surface (upstream end surface) of the main trap material 2 is inclined such that the lower side is the upstream side and the upper side is the downstream side with respect to the flow direction P of exhaust gas.

An electric heater 3 is arranged in front of the main trap material 2, and an auxiliary trap material 4 having an inclined rear surface corresponding to the inclined front surface of the main trap material 2 is arranged in front of the electric heater 3. Electric heater 3 between the material
It has a structure that supports it by sandwiching it. The structure of the electric heater 3 may be, as shown in FIG. As shown in Figure 3, a large number of electric heater elements 3b (A to J)
may be distributed over the entire front surface of the main trap material 2. In addition, the first
In the figure and FIG. 2, 5 is a power supply terminal for the electric heater, and 6 is a ground terminal.

The auxiliary trap material 4 is preferably made of the same material as the main trap material 2 or has a three-dimensional network structure coarser than the main trap material 2, and its thickness in the direction P of exhaust gas flow is similar to that of the main trap material 2. It is assumed to be considerably smaller.
It is also preferable that the lower part of the auxiliary trapping material 4 be relatively dense and the upper part relatively coarse.

Exhaust gas discharged from the engine first passes through the auxiliary trap material 4, so it does not directly hit the electric heater 3. Therefore, when it reaches the electric heater 3, the flow of exhaust gas is weakened, and the exhaust gas generates electricity. Cooling loss of the heater element is reduced. In addition, since stagnation occurs in the exhaust gas when it leaves the auxiliary trap material 4, this stagnation tends to cause more particulates to adhere to the vicinity of the electric heater element, and when the electric heater 3 is energized during regeneration, particulates tend to accumulate. The ignitability of curate is enhanced. In the present invention, since the electric heater 3 is arranged between the inclined surfaces of the main trap material 2 and the auxiliary trap material 4, the area where the electric heater 3 is arranged is expanded especially in the vertical direction, increasing its area. So,
The arrangement density of the electric heater elements 3a, 3b in the exhaust gas flow direction P can be increased, thereby making it possible to increase the thermal energy for particulate regeneration. In addition, since the electric heater 3 is arranged so that its lower side is on the upstream side and its upper side is on the downstream side, when particulate is ignited in the lower area of the electric heater 3 during regeneration, the fire will rise and the auxiliary The trap material 4 itself is effectively regenerated.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the exhaust particulate trap of the present invention, and Figures 2 and 3 are schematic cross-sectional views taken along the line - in Figure 1, showing examples of the arrangement of electric heaters used in the present invention. . DESCRIPTION OF SYMBOLS 1... Trap container, 2... Main trap material, 3... Electric heater, 3a, 3b... Heater element, 4... Auxiliary trap material.

Claims (1)

[Claims for Utility Model Registration] 1. A main trap material capable of collecting exhaust particulates and having a front surface inclined with respect to the flow direction of exhaust gas is provided inside a trap container provided in an exhaust passage of an engine, An electric heater is arranged on the inclined front surface of the material, and an auxiliary trap material having an inclined rear surface corresponding to the inclined front surface is provided on the front side of the electric heater, so that the electric heater is sandwiched between the main trap material and the auxiliary trap material. Exhaust particulate trap. 2. The device according to claim 1, wherein the inclined surfaces of the main trap material and the auxiliary trap material are inclined such that the lower side is on the upstream side and the upper side is on the downstream side with respect to the flow direction of exhaust gas.