Diesel engine SCR (selective catalytic reduction) system control method based on urealysis efficiency

An SCR system and urea decomposition technology, applied in the field of diesel engine SCR system control based on urea decomposition efficiency, can solve the problems of leakage of ammonia gas injection, difficulty in determining the injection volume of urea aqueous solution, secondary pollution, etc., to reduce leakage and realize The effect of NOx high-efficiency conversion

Active Publication Date: 2013-12-25
TONGJI UNIV
View PDF5 Cites 8 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, there are still certain technical bottlenecks in urea SCR technology, which is mainly reflected in the difficulty in determining the injection volume of urea aqueous

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Diesel engine SCR (selective catalytic reduction) system control method based on urealysis efficiency
  • Diesel engine SCR (selective catalytic reduction) system control method based on urealysis efficiency
  • Diesel engine SCR (selective catalytic reduction) system control method based on urealysis efficiency

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Embodiment 1: Determine the urea decomposition efficiency by parameters such as diesel engine exhaust temperature, space velocity, and urea aqueous solution injection pressure

[0022] The present invention takes a diesel engine with a displacement of 7 liters as an example, uses simulation software to simulate and calculate the internal reaction of the SCR system of the diesel engine, and obtains the change of urea decomposition efficiency with the exhaust temperature under the condition that other influencing factors remain unchanged relationship, such as figure 1 shown.

[0023] Depend on figure 1 It can be seen that the urea decomposition efficiency increases first and then decreases with the exhaust temperature, and when the exhaust temperature is 350 °C, the corresponding urea decomposition efficiency can reach 97.5%.

[0024] Similarly, we can also obtain the relationship between the urea decomposition efficiency and the space velocity and the injection pre...

Embodiment 2

[0025] Example 2: Steady state control method for diesel engine SCR system based on urea decomposition efficiency

[0026] Based on the previous diesel engine SCR system control method, the present invention considers the influence of urea decomposition efficiency on the required urea aqueous solution injection quantity, so as to optimize the control method. Such as image 3 As shown, the specific implementation process of the method is as follows:

[0027] (1): When the diesel engine speed is 700rpm, 1100rpm, 1500rpm, 1900rpm, 2300rpm, and the load percentage is 20%, 40%, 60%, 80% and 100% respectively, the exhaust flow and exhaust gas flow rate of the diesel engine are obtained Static MAP plot of NO concentration. When the diesel engine speed is 1200rpm and the load percentage is 50%, according to the static MAP diagram of the diesel engine, the exhaust flow rate of the diesel engine under this working condition is 120g / s, and the concentration of NO in the exhaust gas i...

Embodiment 3

[0031] Embodiment 3: Correction of injection amount of aqueous urea solution under transient working conditions

[0032] The control methods in the above embodiments are typical steady-state control methods. However, when the engine is in a transient state, this method is difficult to accurately provide the actual required injection amount of urea solution for the engine.

[0033] Therefore, on the basis of the original control method, according to the NO x The change law of the conversion rate with the exhaust gas temperature and space velocity, etc., and the transient correction of the steady-state injection volume of the urea aqueous solution is carried out to obtain the actual urea aqueous solution injection volume required by the engine under each transient working condition, as shown in Figure 4 shown.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

No PUM Login to view more

Abstract

The invention belongs to the technical field of diesel engine postprocessing, which particularly relates to a diesel engine SCR (selective catalytic reduction) system control method based on the urealysis efficiency. The diesel engine SCR system control method based on the urealysis efficiency comprises the following steps: firstly, proposing a concept of urealysis efficiency, and giving the expression eta=f(t,v,q) of the concept; on the basis, formulating one set of diesel engine SCR system control method; according to the revolving speed and the load percentage by weight of the diesel engine, obtaining the diesel engine exhaust gas flow and the concentration of NOx in exhaust gas by the static MAP picture of the diesel engine so as to solve the basic injection amount Q1 of urea aqueous solution; correcting Q1 by the urealysis efficiency to obtain Q2 which is the injection amount of the urea aqueous amount under the steady state; carrying out transient correction to Q2 by considering the transient condition of the diesel engine; and obtaining the injection amount Q3 of the urea aqueous solution, which is practically required by the diesel engine finally. According to the diesel engine SCR system control method based on the urealysis efficiency, which is disclosed by the invention, the parameter of the urealysis efficiency is introduced in, the injection amount of the urea aqueous solution can be precisely given according to different operation conditions of the diesel engine, and the NH3 leakage rage is effectively lowered while the high-efficiency conversion of NOx is realized.

Description

technical field [0001] The invention belongs to the technical field of post-treatment of diesel engine exhaust, and in particular relates to a diesel engine SCR system control method based on urea decomposition efficiency. Background technique [0002] Due to its good power and economy, diesel engines are widely used in various vehicles, construction machinery and agricultural machinery. However, nitrogen oxides (NO x ) emission is one of the main air pollutants, which has caused great harm to the environment and human health. Reducing NOx in Diesel Engines by Purifying Measures in Engine x The emission method has been difficult to meet the increasingly stringent emission regulations, so the current research focus turns to diesel engine aftertreatment technology. And in many lower NO x Among the post-treatment technologies for emissions, ammonia (NH 3 ) as a reducing agent, Selective Catalytic Reduction (SCR) is one of the most promising technologies, and in practical ...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
IPC IPC(8): F01N9/00F01N3/20
CPCY02T10/12Y02T10/40
Inventor 谭丕强杜加振胡志远楼狄明
Owner TONGJI UNIV
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap