Sampling channel switching system of partial flow dilution sampling system

Abstract

The invention discloses a sampling channel switching system of a partial flow dilution sampling system, belonging to the technical field of detection of engines and aiming to solve the technical problem that adjacent test benches share one set of sampling system. The switching system comprises a first sampling pipeline and a second sampling pipeline separately used for connecting different exhaustpipes and further comprises a T-socket and a switching control box, wherein the first sample pipeline and the second sampling pipeline are connected with a filter paper rack through the T-socket, electrically controlled components of the first sampling pipeline are electrically connected with a control cabinet through the switching control box, correspondingly, electrically controlled componentsof the second sampling pipeline are electrically connected with the control cabinet through the switching control box. Adjacent test benches can share one set of partial flow dilution sampling systemwithout disassembling the sampling pipeline, so that the system is safe to use and guarantees detection accuracy.

Description

technical field [0001] The invention relates to the technical field of engine detection, in particular to a sampling channel switching system of a partial flow dilution sampling system. Background technique [0002] The emission pollutants of diesel engines mainly include carbon monoxide (CO), hydrocarbons (THC), nitrogen oxides (NOx) and particulate matter (PM), among which nitrogen oxides and particulate matter are the emission pollutants that need to be controlled. The development and testing of diesel engine emission control is mainly based on the engine test bench test. According to the different test principles, it can be divided into full flow dilution sampling system and partial flow dilution sampling system. The SPC472 partial flow dilution sampling system produced by AVL company is one of them. typical representative. [0003] SPC 472 partial flow dilution sampling system is generally composed of filter paper holder, control cabinet, air conditioning system, compu...

AI Technical Summary

Problems solved by technology

[0007] 1. At the end of the test, the exhaust pipe is at a relatively high temperature. If the sampling channel is removed and the sampling port is blocked at this time, it is easy to cause burns. If the exhaust pipe is allowed to cool naturally, it will take a long time to prepare for the test. low efficiency;

[0008] 2. The total length of the sampling probe, transmission pipe and dilution channel is more than 1 meter, and the connecting pipe and dilution pipe are also wrapped with heating wires and multi-layer insulation materials. It is easy to be interfered in the equipment room with narrow space and many pipelines, and The sampling channel is a precise and expensive part, and the process of moving and disassembling requires extra care. Usually, at least two people are required to cooperate to complete it, which is time-consuming and laborious, and the efficiency of test preparation is low;

[0009] 3. The joints of the sampling channel are fastened with threads. In the high-temperature working environment for a long time, it is easy to be sintered and stuck, and frequent disassembly and assembly will cause the thread to be worn, resulting in slipping teeth, making disassembly and assembly difficult, and even need to replace a new sampling probe. Inefficient test preparation;

[0010] 4. Poor sealing of joints is likely to occur when switching sampling channels, resulting in failure of leak inspection, increasing the difficulty of leak inspection, increasing the time of equipment inspection, and further affecting the progress of test development;

[0011] 5. When switching the sampling channel, it is easy to cause the heating wire to loosen and the insulation layer to be damaged, resulting in uneven heating and increased particle adsorption, thus affecting the stability and accuracy of the measurement results;

[0012] 6. Since the 220V power supply of the heating line of the sampling channel is directly controlled by the contacts of the PLC relay output module in the control cabinet, large currents frequently flow through the contacts, which will easily lead to failure of the relay output module, increase equipment maintenance time, and increase maintenance and replacement cost of spare parts;

[0013] 7. After consultation with AVL company, if AVL is entrusted with the design and rectification to add dual-channel sampling function to the SPC472 partial flow dilution sampling system, it will cost 500,000 yuan, which is almost equal to the price of half a new set of equipment

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