JPS5913940A - Analyzer of sulfur in automobile exhaust gas - Google Patents

Abstract

PURPOSE:To suppress adsorption of unburned oil and its condensation, by directly applying voltage from a power supply to the introduction pipe of an exhaust gas to use the pipe as a heat generating body for heating the gas, and effectively heating said pipe and said gas to high temp. CONSTITUTION:The output terminals 9a, 9b of a low voltage circuit 9 consisting of a power supply 7 and a voltage lowering transformer 8 to the two proper positions of the forward introduction pipe 5 of the exhaust gas connecting the exhaust pipe of an engine to a pretreatment oxidation furnace 4, and voltage is applied to the pipe 5 to directly heat it to a temp. similar to that of the engine exhaust pipe and to heat the exhaust gas. Heating of the pipe and the gas is carried out efficiently and economically, and the adsorption and condensation of unburned oil to the pipe wall is effectively prevented, and measurement of sulfur is enhanced in accuracy by effectively introducing the sulfur in the gas from the engine into said furnace without any loss.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an apparatus for analyzing sulfur contained in automobile exhaust gas.

This type of sulfur analyzer generally has a pretreatment oxidation furnace 4 interposed in the exhaust gas introduction line from the exhaust pipe 2 of the engine 1 to the analyzer 3, as shown in FIG.
By heating to about 1000°C, unburned oil and most of the HC (hydrocarbons) and CO (-carbon oxide) in the exhaust gas passing through the furnace 4 are combusted and oxidized to form SO□ (dioxide). sulfur), H2O (water), and CO□ (carbon dioxide), thereby making it possible to measure the sulfur content in the exhaust gas. , 6, especially on the side of the front exhaust gas introduction pipe 5 that connects the exhaust pipe 2 and the pretreatment oxidation furnace 4, the exhaust gas that has not yet been subjected to the combustion oxidation treatment in the pretreatment oxidation furnace 4 flows, so that the Unburned oil, which is very easily adsorbed, adsorbs and condenses on the pipe wall, and the resulting loss of sulfur content in the exhaust gas makes it impossible to obtain accurate analytical data. It becomes necessary to heat the material to prevent the above-mentioned adsorption, etc.

However, the conventional method of heating exhaust gas in the front exhaust gas introduction pipe 5 is a so-called two-stage heating method in which the exothermic energy of a heater wrapped around the outer periphery of the front exhaust gas introduction pipe 5 is applied to the exhaust gas through the pipe 5. Since the indirect heating method used in
FC has the disadvantage that it cannot be heated above the optimum temperature of 400-500'C to prevent condensation.

The present invention has been made in view of the above points, and the present invention efficiently heats the exhaust gas introduction pipe and the exhaust gas flowing therein to a high temperature, and adsorbs unburned oil onto the exhaust gas introduction pipe.
The present invention provides an apparatus for analyzing sulfur in automobile exhaust gas that can effectively suppress condensation phenomena.

Hereinafter, one embodiment of the present invention will be described based on FIG.
A low voltage circuit 9 consisting of a power supply 7 and a step-down transformer 8 is provided, and an output terminal 9a191) of the low-voltage circuit 9, that is, a secondary terminal of the step-down transformer 80 is connected to an engine exhaust pipe (not shown) and a pretreatment oxidation furnace. 4, and by applying voltage and energization to the front exhaust gas introduction pipe 5, the limb pipe 5 is connected to the engine. Almost the same temperature as exhaust pipe 2 400
It is directly heated to ~500'C, and the heat generated by the front exhaust gas introduction pipe 5 is used to heat the exhaust gas flowing inside the pipe.

In the figure, 10 indicates a heat insulating insulator coated on the outer periphery of the front exhaust gas introduction pipe 5, and in the pretreatment oxidation furnace 4, a heater 12 connected to a power supply (not shown) is installed on the outer periphery of the exhaust gas distribution pipe 11. These 11 and 12 are wrapped with a heat insulator 13.
covered with.

Furthermore, in the rear exhaust gas introduction pipe 6 leading from the pretreatment oxidation furnace 4 to the analyzer (not shown), since the exhaust gas passes through the pretreatment oxidation furnace 4 in the previous stage, the problem of adhesion of unburned oil does not occur. It is only necessary to heat the limb tube 6 to a low temperature that prevents condensation of moisture, and there is no problem in using an existing type of heater 14 for heating. 15 is a heat insulator.

As described above, the present invention does not indirectly heat the exhaust gas with a heater wrapped around the exhaust gas introduction pipe, but directly heats the pipe by applying a power supply voltage to the exhaust gas introduction pipe to give heat generation energy to the exhaust gas. Therefore, it is possible to raise the temperature of the exhaust gas introduction pipe and heat the exhaust gas efficiently and economically, and because of this efficient direct heating, the exhaust gas introduction pipe can be heated to almost the same high temperature as the engine exhaust pipe (400 to 500°C). (above), effectively prevents adsorption and condensation of unburned oil on the pipe wall, and leads the sulfur content in the exhaust gas from the engine to the pretreatment oxidation furnace without loss. This is beneficial because it can contribute to improving the accuracy of sulfur content measurement.

In addition, due to the high efficiency of heating mentioned above, if the length of the exhaust gas introduction pipe is made long and the material used is highly heat resistant, the pipe itself can be heated to 1000'C and have the same function as a pretreatment oxidation furnace. Since it is possible to make the equipment for the furnace unnecessary, there is an advantage that the analyzer can be simplified and the cost can be reduced.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a general configuration example of an apparatus for analyzing sulfur in automobile exhaust gas, and FIG. 2 is an enlarged sectional view of a main part of a sulfur analyzer having a structure according to an embodiment of the present invention. 3... Sulfur analyzer, 5... Exhaust gas introduction pipe, 10...
- Heat insulator. (5) Figure 1

Claims (1)

[Claims] An automobile characterized in that the outer periphery of a metal exhaust gas introduction pipe for introducing automobile exhaust gas into a sulfur analyzer is covered with a heat insulating material, and the pipe is used as a heating element for heating the exhaust gas by directly applying a power supply voltage to the pipe. Sulfur analyzer in exhaust gas.