Three-way catalytic converters play a key role in reducing vehicle emissions. The substrate Support Mat is an important component in the catalytic converter. It can fix and support the carrier so that it will not be damaged, and it also acts as a seal and heat insulation. . The rationality of the relevant parameters of the Substrate Support Mat directly affects the encapsulation and service life of the catalyst. Therefore, there are a few things to pay attention to when selecting the Substrate Support Mat:

1) Substrate Support Mat category

Substrate Support Mat is divided into inflated and non-inflated. The expanded Substrate Support Mat is composed of fiber + vermiculite + binder. The vermiculite in the Substrate Support Mat expands when exposed to high temperatures. After the vermiculite expands, it exerts a radial force on the carrier, thereby holding the carrier for protection. non-expanded

The key to catalyst design is encapsulation. In the process of catalyst design, the appropriate Substrate Support Mat is composed of fibers + binders. The fibers in the Substrate Support Mat are packaged and compressed to generate packaging pressure, which is similar to a spring and clamps. The carrier plays a protective role

2) Three-way catalytic converter carrier

The surface temperature of the close-coupled catalytic converter carrier is about 800°C, the exhaust vibration is large, and the airflow has a strong impact on the Substrate Support Mat, so the non-expandable Substrate Support Mat is preferred. The surface temperature of the chassis-type catalytic converter carrier is about 600°C, the vibration of the exhaust gas is small, the impact force of the airflow on the Substrate Support Mat is small, and the expanded Substrate Support Mat is preferred.

3) Substrate Support Mat pressure

The Substrate Support Mat protects and seals the carrier, and lasts the entire life cycle of the catalytic converter

Providing reliable thermal insulation performance during the period, which requires the pressure of the Substrate Support Mat to the carrier must be

It must be kept within a certain design window to avoid excessive pressure carrier breakage or

If the pressure is too small, the carrier moves, that is, it requires: 

1) Substrate Support Mat pressure design value < carrier diameter

2) Substrate Support Mat pressure design value > the maximum required to ensure that the carrier does not move Smallholding power. The minimum holding force required for the carrier is calculated as follows:

[msxgl-+△P×SAs/u/SAm

In the formula: ms - the mass of the carrier after coating, in kilograms (kg):g

- Vibration acceleration, in meters per square second (ms); △P - front of the carrier

The back pressure difference, the unit is Pa (Pa); SAs is the cross-sectional area of the carrier, and the unit is flat

Square millimeter (mm): sAm—the contact area between the Substrate Support Mat and the circumference of the carrier, the unit is flat

Square millimeter (mm): u is the friction coefficient between the Substrate Support Mat and the shell.

After the carrier is selected, its radial compressive strength value can be determined.

Calculate the minimum holding force required by the carrier to determine the pressure range value of the Substrate Support Mat

4) Substrate Support Mat GBD

The key to the catalyst is the packaging. In the design process of the catalyst, a reasonable range of packaging pressure (ie Substrate Support Mat pressure) is selected, and the output is in the form of Substrate Support Mat packaging density GBD. The Substrate Support Mat pressure is proportional to GBD. The packaging process The control Substrate Support MatGBD meets the requirements, that is, the required holding force of the carrier can be met without being crushed.

1) GBD lower limit determination: the minimum retention given by the Substrate Support Mat required after the carrier is encapsulated

The force (minimum pressure of Substrate Support Mat) can be calculated by the formula, and the lower limit of GBD is determined according to the relationship between the pressure of Substrate Support Mat and GBD.

2) GBD upper limit determination: The maximum value of Substrate Support Mat pressure is obtained from the radial compressive strength of the carrier, and the GBD upper limit value is determined according to the relationship between the Substrate Support Mat pressure and GBD.

The above is the whole content of the Substrate Support Mat selection that KY-Mat brought to you. I hope it will be helpful to you. See you in the next issue.