CN211500756U

CN211500756U - External purification system of diesel engine

Info

Publication number: CN211500756U
Application number: CN201922077988.2U
Authority: CN
Inventors: 张艳山; 闫守成; 李福荣; 高迎春
Original assignee: Huanghuai University
Current assignee: Huanghuai University
Priority date: 2019-11-27
Filing date: 2019-11-27
Publication date: 2020-09-15
Anticipated expiration: 2029-11-27

Abstract

The utility model provides an external purifying system of diesel engine, which organically combines a particle catcher, a catalytic reduction system and an exhaust gas recirculation system together and controls each part through the mutual cooperation of a multi-way sensor and an ECU, thereby playing a role in thoroughly and perfectly purifying the tail gas of the diesel engine; and simultaneously, the utility model provides a set up multichannel clean system in the exhaust system of diesel engine, can be incessant handle engine combustion exhaust, reach thorough and perfect purifying effect equally.

Description

External purification system of diesel engine

Technical Field

The utility model relates to a soot and granule processing apparatus of diesel engine is a diesel engine external purification system particularly.

Background

The diesel engine is an engine which burns diesel oil to obtain energy, and has the advantages of large torque, good economic performance and the like, but the diesel engine also has some disadvantages in the working process, such as higher noise and vibration and serious soot and particle emission, and the existing diesel engine is provided with a corresponding soot and particle treatment device or system in the application to treat the emission of the diesel engine so as to reduce the pollution of the tail gas of the diesel engine to the environment. With the current escalation of environmental protection requirements, the emission problem of diesel engines has become a key problem restricting the further development thereof.

Currently, main devices and systems for soot and particulate treatment of diesel engines include particulate traps, catalytic reduction systems, and exhaust gas recirculation systems. A particulate trap, DPF for short, is a ceramic filter installed in the exhaust system of diesel engines to trap particulate emissions before they enter the atmosphere; the catalytic reduction system is an important mode in the exhaust gas treatment of the diesel engine, and a selective catalytic reduction method, SCR for short, is generally selected in the exhaust gas treatment of the diesel engine and is used for treating nitrogen oxides in the exhaust gas under the action of urea aqueous solution; the EGR is a waste gas recirculation system, and is characterized in that part of waste gas discharged by an engine is returned to an air inlet pipe, so that the waste gas and fresh mixed gas enter a cylinder again, and the waste gas contains a large amount of polyatomic gas such as carbon dioxide, the gas such as the carbon dioxide cannot be combusted, but absorbs a large amount of heat due to high specific heat capacity of the gas, so that the highest combustion temperature of the mixed gas in the cylinder is reduced, and the generation amount of nitrogen oxides is reduced.

Disclosure of Invention

The utility model discloses realize above-mentioned purpose and adopt following technical scheme:

the external purification system of the diesel engine comprises a particle catcher, a catalytic reduction system and an exhaust gas recirculation system, wherein the particle catcher, the catalytic reduction system and the exhaust gas recirculation system are sequentially arranged in an exhaust pipeline of the diesel engine; an oxidation type catalyst is further arranged between the catalytic reduction system and the exhaust gas recirculation system, a urea tank and a urea injection controller for controlling urea injection are arranged between the particle catcher and the catalytic reduction system, the urea tank is arranged on a branch of an exhaust pipeline between the particle catcher and the catalytic reduction system, and a drying treatment device is further arranged between the urea tank and the catalytic reduction system; exhaust back pressure sensors are respectively arranged at two ends of the particle catcher, and a nitrogen oxide sensor is arranged at the front part of the exhaust pipeline corresponding to the urea tank; the exhaust back pressure sensor, the nitrogen oxide sensor, the urea injection controller and the exhaust gas recirculation system are connected to an ECU of the automobile through lines.

The exhaust gas recirculation system comprises a branch pipe arranged between an exhaust pipeline and an engine air inlet pipeline, wherein an electric control valve and a cooler are arranged on the branch pipe, and the electric control valve is connected to an ECU (electronic control Unit) of the automobile through a line.

The particle catcher, the catalytic reduction system and the exhaust gas recirculation system are provided with two groups which are mutually connected in parallel, and each group of particle catcher, the catalytic reduction system and the exhaust gas recirculation system form a corresponding exhaust branch pipe; the exhaust branch pipe is provided with an electromagnetic air valve; the electromagnetic valve is connected to the ECU of the automobile through a line.

Furthermore, the particle catcher is provided with two groups which are mutually connected in parallel, and the catalytic reduction system and the exhaust gas recirculation system are provided with one group; an electromagnetic valve is arranged on an exhaust branch pipe at the front part of the particle catcher and connected to an ECU of an automobile through a line, and the electromagnetic valve controls the flow direction of exhaust.

The utility model adopts the above technical scheme following beneficial effect has:

the tail gas of the diesel engine can be efficiently treated by adopting a combination of various treatment modes, so that the content of harmful substances in the exhaust gas of the diesel engine is greatly reduced, and the effect of high purification is realized.

The two-way or multi-way particle catcher is arranged, so that interruption processing can be avoided even in the process that the single-way particle catcher is saturated and needs to be regenerated, and the continuity of exhaust gas treatment is ensured.

The multi-sensor combined treatment and control mode can ensure that the treatment system carries out reasonable and effective treatment according to actual conditions, particularly for the urea injection link in the catalytic reduction system, the urea injection quantity can be accurately controlled, and the influence of too much or too little urea injection on the exhaust treatment system is prevented.

Drawings

Fig. 1 is a schematic view of the present invention.

Detailed Description

The present invention will be further explained with reference to the accompanying drawings.

The external purification system of the diesel engine shown in fig. 1 comprises a particle catcher, a catalytic reduction system and an exhaust gas recirculation system, wherein the particle catcher, the catalytic reduction system and the exhaust gas recirculation system are sequentially arranged in an exhaust pipeline of the diesel engine; an oxidation type catalyst is further arranged between the catalytic reduction system and the exhaust gas recirculation system, a urea tank and a urea injection controller for controlling urea injection are arranged between the particle catcher and the catalytic reduction system, the urea tank is arranged on a branch of an exhaust pipeline between the particle catcher and the catalytic reduction system, and a drying treatment device is further arranged between the urea tank and the catalytic reduction system; exhaust back pressure sensors are respectively arranged at two ends of the particle catcher, and a nitrogen oxide sensor is arranged at the front part of the exhaust pipeline corresponding to the urea tank; the exhaust back pressure sensor, the nitrogen oxide sensor, the urea injection controller and the exhaust gas recirculation system are connected to an ECU of the automobile through lines.

The particle catcher is provided with two groups which are mutually connected in parallel, and the catalytic reduction system and the exhaust gas recirculation system are provided with one group; the particle trap is characterized in that an electromagnetic valve is arranged on an exhaust pipeline in front of the particle trap and connected to an ECU of an automobile through a pipeline, and the electromagnetic valve controls the flow direction of exhaust.

Each exhaust branch pipe is provided with an electric control valve, one valve is opened and the other valve is closed in the exhaust process, the particle catcher of the opened exhaust branch pipe starts to adsorb particles in the exhaust by using the internal structure of the porous ceramic of the particle catcher, the pressure difference between two ends of the exhaust branch pipe is increased along with the accumulation of the particles, an exhaust back pressure sensor at the tail end of the exhaust pipe feeds back the data of the pressure difference to the ECU, and when the value of the pressure difference is larger than the set value of the ECU, the ECU sends out a pulse instruction and outputs pulse current to close the electric control electromagnetic valve and open the other electromagnetic valve. Then, a certain amount of fuel is injected into the front end of the particle catcher of the closed exhaust branch pipe, and the particles are combusted and regenerated. At the moment, the nitrogen oxide sensor transmits a concentration signal of nitrogen oxide to an ECU of the automobile, and sends an instruction to the electronic control urea injection controller to inject a certain amount of urea aqueous solution into the catalytic reduction system. Otherwise, the urea aqueous solution is too little, so that nitrogen oxides cannot be completely reduced; too much urea water solution causes too large load of the oxidation catalyst at the lower end of the device, reduces the service life of the device and wastes urea raw materials. Then the air is dried, so that the moisture in the exhaust gas can be absorbed, and the sulfate production amount can be reduced. At the same time, the throttle position sensor and the nitrogen oxide sensor respectively feed back the position of the accelerator pedal and the concentration of the nitrogen oxide to the ECU so as to control an electric control valve in the electric control cooling exhaust gas recirculation system, comprehensively control the exhaust gas recirculation rate and reduce the generation of the nitrogen oxide, thereby achieving the purpose of reducing the emission of pollutants.

Claims

1. The utility model provides a diesel engine external purification system, it includes particle trapper, catalytic reduction system and exhaust gas recirculation system, its characterized in that: the particle catcher, the catalytic reduction system and the exhaust gas recirculation system are sequentially arranged in an exhaust pipeline of the diesel engine; an oxidation type catalyst is further arranged between the catalytic reduction system and the exhaust gas recirculation system, a urea tank and a urea injection controller for controlling urea injection are arranged between the particle catcher and the catalytic reduction system, the urea tank is arranged on a branch of an exhaust pipeline between the particle catcher and the catalytic reduction system, and a drying treatment device is further arranged between the urea tank and the catalytic reduction system; exhaust back pressure sensors are respectively arranged at two ends of the particle catcher, and a nitrogen oxide sensor is arranged at the front part of the exhaust pipeline corresponding to the urea tank; the exhaust back pressure sensor, the nitrogen oxide sensor, the urea injection controller and the exhaust gas recirculation system are connected to an ECU of the automobile through lines.

2. The diesel engine external purification system of claim 1, wherein: the exhaust gas recirculation system comprises a branch pipe arranged between an exhaust pipeline and an engine air inlet pipeline, wherein an electric control valve and a cooler are arranged on the branch pipe, and the electric control valve is connected to an ECU (electronic control Unit) of the automobile through a line.

3. The diesel engine external purification system of claim 2, wherein: the particle catcher, the catalytic reduction system and the exhaust gas recirculation system are provided with two groups which are mutually connected in parallel, and each group of particle catcher, the catalytic reduction system and the exhaust gas recirculation system form a corresponding exhaust branch pipe; the exhaust branch pipe is provided with an electromagnetic air valve; the electromagnetic valve is connected to the ECU of the automobile through a line.

4. The diesel engine external purification system of claim 3, wherein: the particle catcher is provided with two groups which are mutually connected in parallel, and the catalytic reduction system and the exhaust gas recirculation system are provided with one group; an electromagnetic valve is arranged on an exhaust branch pipe at the front part of the particle catcher and connected to an ECU of an automobile through a line, and the electromagnetic valve controls the flow direction of exhaust.