CN205720167U - Optimization urea concentration assay device for diesel engine after treatment - Google Patents

Abstract

The utility model discloses an optimized urea concentration test device for aftertreatment of diesel engines. The catalytic converter quick connector is connected to the catalytic converter, and the catalytic converter is connected to the exhaust gas connecting pipe through the rear catalytic converter quick connector, and the exhaust gas connecting pipe is placed into the exhaust gas treatment pool, and the exhaust gas treatment pool is provided with an exhaust gas tail pipe; A urea nozzle is provided at the front end of the urea decomposition pipe, and a rear ammonia sampling port is provided at the rear end of the urea nozzle; a front ammonia sampling port is provided between the ammonia sampling port behind the urea nozzle and the catalytic converter, and a rear ammonia sampling port is provided on the exhaust gas connecting pipe. Ammonia sampling port. The device of the utility model can find out the optimum urea concentration for the selective catalytic reduction post-treatment system reaction at different temperatures.

Description

Optimized urea concentration test device for diesel engine aftertreatment

technical field

The utility model relates to the field of aftertreatment of nitrogen oxides of internal combustion engines, in particular to an optimized urea concentration test device for aftertreatment of diesel engines.

Background technique

In order to reduce the emission of nitrogen oxides and particulate matter from motor vehicles, the state has formulated a series of emission regulations. At present, the main technical means to make diesel vehicles adapt to the National IV and National V standards is the selective catalytic reduction post-treatment technology with urea solution as the reducing agent. The reducing agent of the selective catalytic reduction aftertreatment system is mainly 32.5% urea solution, which has the lowest freezing point. However, for some areas or seasons with high ambient temperature, such a low freezing point may not be required, and urea should be supplied to the post-treatment system with the optimal urea concentration.

Utility model content

The technical problem to be solved by the utility model is to provide an optimized urea concentration test device for aftertreatment of diesel engines, which can find out the optimal urea concentration for the reaction of the selective catalytic reduction aftertreatment system at different temperatures.

In order to solve the problems of the technologies described above, the technical solution adopted in the utility model is:

An optimized urea concentration test device for aftertreatment of diesel engines, one end of the urea decomposition tube is connected to the engine exhaust pipe through a quick connector of the urea decomposition tube, and the other end of the urea decomposition tube is connected to the catalytic converter through a quick connector of the front catalyst, The catalytic converter is connected to the exhaust gas connecting pipe through the rear catalytic converter quick connector, and the exhaust gas connecting pipe is placed in the exhaust gas treatment pool, and the exhaust gas treatment pool is provided with an exhaust gas tail pipe;

A urea nozzle is provided at the front end of the urea decomposition pipe, and a rear ammonia sampling port is provided at the rear end of the urea nozzle; a front ammonia sampling port is provided between the ammonia sampling port behind the urea nozzle and the catalytic converter, and a rear ammonia sampling port is provided on the exhaust gas connecting pipe. Ammonia sampling port.

According to the above solution, a water nozzle is provided between the rear ammonia sampling port and the front ammonia sampling port of the urea nozzle.

According to the above scheme, a front pressure sensor and a temperature sensor in front of the urea nozzle are also provided between the quick connector of the urea decomposition pipe and the urea nozzle, and a temperature sensor behind the urea nozzle is provided between the urea nozzle and the ammonia sampling port behind the urea nozzle. A temperature sensor before the catalyst is installed between the quick connector of the catalyst and the ammonia sampling port behind the urea nozzle, and a temperature sensor and a pressure sensor after the catalyst are installed on the exhaust gas connecting pipe.

According to the above scheme, the exhaust gas treatment pool is a sealed box, and the exhaust gas treatment liquid is installed inside it.

Compared with the prior art, the beneficial effects of the utility model are: 1) can measure the urea pyrolysis, hydrolysis and total ammonia production respectively, analyze the efficiency of each step reaction; 3) The temperature distribution and ammonia distribution at different positions in the radial direction can be monitored to provide data for subsequent analysis; 4) The influence of water on the exhaust temperature can be monitored; 5) It can display solid urea pyrolysis efficiency, hydrolysis efficiency and nitrogen oxide conversion efficiency in real time.

Each ammonia sampling port is inserted into the tube at different radial depths along the circumference to measure the temperature distribution at different radial positions in the tube. Each temperature sensor is inserted into the tube at different radial depths along the circumference to measure the distribution of ammonia gas at different radial positions in the tube.

Description of drawings

Fig. 1 is a structural schematic diagram of an optimized urea concentration test device for diesel engine post-treatment according to the present invention.

Fig. 2 is the radial arrangement of each temperature sensor in the utility model.

Fig. 3 is the radial arrangement of each ammonia sampling port in the utility model.

In the figure: urea decomposition pipe quick connector 1, front pressure sensor 2, temperature sensor in front of urea nozzle 3, urea nozzle 4, urea decomposition pipe 5, temperature sensor behind urea nozzle 6, ammonia sampling port 7 behind urea nozzle, water nozzle 8, Catalyst front temperature sensor 9, front ammonia sampling port 10, front catalytic converter quick connector 11, catalytic converter 12, rear catalytic converter quick connector 13, catalytic converter rear temperature sensor 14, rear pressure sensor 15, rear ammonia sampling port 16, exhaust gas Connecting pipe 17, waste gas treatment tank 18, waste gas tailpipe 19.

detailed description

Below in conjunction with accompanying drawing and specific embodiment, the utility model is described in further detail. The utility model provides an optimized urea concentration test device for post-treatment of diesel engines. Its structure is: one end of the urea decomposition pipe 5 is connected to the engine exhaust pipe through the urea decomposition pipe quick joint 1, and the other end of the urea decomposition pipe 5 One end is connected to the catalytic converter 12 through the front catalytic converter quick joint 11, and the catalytic converter 12 is connected to the exhaust gas connecting pipe 17 through the rear catalytic converter quick joint 13, and the exhaust gas connecting pipe 17 is inserted into the exhaust gas treatment pool 18, so The exhaust gas treatment pool 18 is provided with an exhaust tailpipe 19;

The front end of the urea decomposition pipe 5 is provided with a urea nozzle 4, and the rear end is provided with an ammonia sampling port 7 after the urea nozzle; a front ammonia sampling port 10 is arranged between the ammonia sampling port 7 and the catalytic converter 12 after the urea nozzle, and the exhaust gas A rear ammonia sampling port 16 is provided on the connecting pipe 17 .

A water nozzle 8 is provided between the rear ammonia sampling port 7 and the front ammonia sampling port 10 of the urea nozzle.

A front pressure sensor 2 and a temperature sensor 3 in front of the urea nozzle are also provided between the urea decomposition pipe quick joint 1 and the urea nozzle 4, and a temperature sensor 6 after the urea nozzle is provided between the urea nozzle 4 and the ammonia sampling port 7 behind the urea nozzle A temperature sensor 9 before the catalyst is provided between the quick connector 11 of the front catalyst and the ammonia sampling port 7 after the urea nozzle, and a temperature sensor 14 and a pressure sensor 15 after the catalyst are provided on the exhaust gas connecting pipe 17 .

The exhaust gas treatment pool 18 is a sealed box, and the exhaust gas treatment liquid is installed inside it.

As shown in Figure 2, each ammonia sampling port is inserted into the tube at different radial depths along the circumference to measure the temperature distribution at different radial positions in the tube. As shown in Figure 3, each temperature sensor is inserted into the tube at different radial depths along the circumference to measure the distribution of ammonia gas at different radial positions in the tube.

In addition, the test method of the utility model is described in detail as follows:

1. Observe the production efficiency of ammonia gas to determine the optimal urea injection concentration under different working conditions

Example 1: Spraying "solid urea + water"

1) Urea concentration under a certain working condition:

${\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; NH</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; o</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; m</span>}}_{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; NH</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; o</span>}}}{{\mathrm{<span\; class="notranslate">\; m</span>}}_{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; NH</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; o</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; o</span>}}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 100</span>}\mathrm{<span\; class="notranslate">\; \%</span>}$

In the formula: is the urea concentration; is the injection mass of urea, g; is the injection volume of water, g.

2) Calculation formula of ammonia production efficiency in a certain working condition

In the formula: is the production efficiency of ammonia gas; is the mass of ammonia gas produced by urea decomposition, i.e. the mass of ammonia gas measured at the front ammonia sampling port, g; is the injection mass of urea, g.

3) The implementation steps are: (1) select the working condition of the engine; (2) quantitatively inject urea solids; (3) gradually increase the amount of water injection; (4) observe the production efficiency of ammonia, when the production efficiency reaches the maximum, The urea concentration at this time is the optimal injection concentration for the current working condition.

Embodiment 2: spraying urea solutions of different concentrations

1) Calculation formula of ammonia production efficiency in a certain working condition

In the formula: is the production efficiency of ammonia gas; is the mass of ammonia gas produced by urea decomposition, i.e. the mass of ammonia gas measured at the front ammonia sampling port, g; is the injection mass of urea aqueous solution at the current concentration, g; is the current urea concentration.

2) The implementation steps are: (1) select the working condition of the engine; (2) quantitatively inject urea aqueous solution; (3) gradually increase the injection amount; (4) observe the production efficiency of ammonia, when the production efficiency reaches the maximum, then The urea concentration at the time is the optimal injection concentration for the current working condition.

2. Through the optimal conversion efficiency of nitrogen oxides, the urea injection concentration is used to determine the optimal conversion efficiency of nitrogen oxides under different working conditions

Example 3: Spraying "solid urea+water"

1) Urea concentration under a certain working condition:

${\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; NH</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; o</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; m</span>}}_{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; NH</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; o</span>}}}{{\mathrm{<span\; class="notranslate">\; m</span>}}_{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; NH</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; o</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; o</span>}}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 100</span>}\mathrm{<span\; class="notranslate">\; \%</span>}$

In the formula: is the urea concentration; is the injection mass of urea, g; is the injection volume of water, g.

2) The formula for calculating the conversion efficiency of nitrogen oxides in a certain working condition

In the formula: is the conversion efficiency of nitrogen oxides; is the mass of ammonia gas produced by urea decomposition, i.e. the mass of ammonia gas measured at the front ammonia sampling port, g; is the mass of ammonia gas that did not participate in the reaction after conversion, that is, the mass of ammonia gas measured at the rear ammonia sampling port, g.

3) The implementation steps are: (1) select the working condition of the engine; (2) quantitatively inject urea solid; (3) gradually increase the amount of water injection; (4) observe the conversion efficiency of nitrogen oxides, when the conversion efficiency reaches the maximum , the urea concentration at this time is the optimal injection concentration for the current working condition.

Embodiment 4: spraying urea solutions of different concentrations

1) The formula for calculating the conversion efficiency of nitrogen oxides in a certain working condition

In the formula: is the conversion efficiency of nitrogen oxides; is the mass of ammonia gas produced by urea decomposition, i.e. the mass of ammonia gas measured at the front ammonia sampling port, g; is the mass of ammonia gas that did not participate in the reaction after conversion, that is, the mass of ammonia gas measured at the rear ammonia sampling port, g.

2) The implementation steps are: (1) select the working condition of the engine; (2) quantitatively inject urea aqueous solution; (3) gradually increase the injection amount; (4) observe the conversion efficiency of nitrogen oxides, when the conversion efficiency of nitrogen oxides reaches At the maximum, the urea concentration at this time is the optimal injection concentration for the current working condition.

Wherein η _pyrolysis is urea solid pyrolysis produces NH Efficiency _; is the amount of NH produced by urea solid pyrolysis, that is, the amount measured at the ammonia sampling port ₇ behind the urea nozzle, in g; is the injection mass of urea, in g;

Wherein η _hydrolysis is urea solid hydrolysis and produces NH Efficiency _; is the total ammonia mass produced by urea pyrolysis and hydrolysis, i.e. the ammonia mass measured at the front ammonia sampling port 10, in g; is the amount of NH produced by urea solid pyrolysis, that is, the amount measured at the ammonia sampling port ₇ behind the urea nozzle, in g; is the injection mass of urea, in g.

Claims (4)

1. an optimized urea concentration test device for diesel engine aftertreatment, it is characterized in that one end of the urea decomposition pipe (5) is connected to the engine exhaust pipe by the urea decomposition pipe quick connector (1), and the urea decomposition pipe (5) ) is connected to the catalytic converter (12) through the front catalytic converter quick joint (11), and the catalytic converter (12) is connected to the exhaust gas connecting pipe (17) through the rear catalytic converter quick joint (13), and the exhaust gas The connecting pipe (17) is inserted into the exhaust gas treatment pool (18), and the exhaust gas treatment pool (18) is provided with an exhaust gas tailpipe (19); The front end of the urea decomposition pipe (5) is provided with a urea nozzle (4), and the rear end is provided with an ammonia sampling port (7) after the urea nozzle; between the ammonia sampling port (7) and the catalytic converter (12) after the urea nozzle A front ammonia sampling port (10) is provided, and a rear ammonia sampling port (16) is provided on the waste gas connecting pipe (17). 2. the optimized urea concentration test device for diesel engine aftertreatment as claimed in claim 1, is characterized in that, between ammonia sampling port (7) and front ammonia sampling port (10) after described urea nozzle, be provided with water nozzle (8). 3. the optimized urea concentration test device for diesel engine aftertreatment as claimed in claim 1 or 2, is characterized in that, also be provided with front pressure sensor between urea decomposition pipe quick connector (1) and urea nozzle (4) (2), the temperature sensor (3) in front of the urea nozzle, the temperature sensor (6) behind the urea nozzle is arranged between the urea nozzle (4) and the ammonia sampling port (7) behind the urea nozzle, and the front catalytic converter quick connector (11 ) and the ammonia sampling port (7) behind the urea nozzle is provided with a temperature sensor (9) before the catalyst, and a temperature sensor (14) and a pressure sensor (15) after the catalyst are provided on the exhaust gas connecting pipe (17). 4. The optimized urea concentration test device for diesel engine post-treatment as claimed in claim 3, characterized in that, the waste gas treatment tank (18) is a sealed box with waste gas treatment liquid inside.