阅读说明：本技术 Scr平均温度算法的优化方法 (Optimization method of SCR average temperature algorithm ) 是由 李明星 王辉 刘星 桑海浪 张扬 何传成 于 2020-05-08 设计创作，主要内容包括：本发明公开了一种SCR平均温度算法的优化方法,包括以下步骤：获取SCR载体的上游传感器的实际温度值；获取SCR载体的下游传感器的实际温度值；计算并获取SCR载体的平均温度值；计算SCR载体的上游传感器的实际温度值和SCR载体的下游传感器的实际温度值的偏差值；获取通过SCR载体的排气流量值；通过偏差值和排气流量值查寻相应的修正系数值；以及通过平均温度值和修正系数值计算得到SCR载体的温度值。本发明的SCR平均温度算法的优化方法,其通过SCR载体的上下游传感器的实际温度平均值和修正系数值获得的SCR载体的温度更加精准。(The invention discloses an optimization method of an SCR average temperature algorithm, which comprises the following steps: acquiring an actual temperature value of an upstream sensor of the SCR carrier; acquiring an actual temperature value of a downstream sensor of the SCR carrier; calculating and obtaining an average temperature value of the SCR carrier; calculating an offset value of an actual temperature value of an upstream sensor of the SCR carrier and an actual temperature value of a downstream sensor of the SCR carrier; acquiring an exhaust flow value passing through an SCR carrier; searching a corresponding correction coefficient value through the deviation value and the exhaust flow value; and calculating the temperature value of the SCR carrier through the average temperature value and the correction coefficient value. According to the optimization method of the SCR average temperature algorithm, the temperature of the SCR carrier obtained through the actual temperature average value and the correction coefficient value of the upstream and downstream sensors of the SCR carrier is more accurate.)

1. An optimization method of an SCR average temperature algorithm is characterized by comprising the following steps:

acquiring an actual temperature value of an upstream sensor of the SCR carrier;

acquiring an actual temperature value of a downstream sensor of the SCR carrier;

calculating and obtaining an average temperature value of the SCR carrier;

calculating an offset value of the actual temperature value of the upstream sensor of the SCR carrier and the actual temperature value of the downstream sensor of the SCR carrier;

acquiring an exhaust flow value passing through the SCR carrier;

searching a corresponding correction coefficient value through the deviation value and the exhaust flow value; and

and calculating the temperature value of the SCR carrier according to the average temperature value and the correction coefficient value.

2. The method for optimizing the SCR average temperature algorithm according to claim 1, wherein the temperature value of the SCR substrate is calculated by the following formula:

the temperature value of the SCR carrier is (A + B)/2 xM;

wherein A is an actual temperature value of a sensor upstream of the SCR carrier;

b is an actual temperature value of a downstream sensor of the SCR carrier;

m is a correction coefficient value corresponding to the (A-B) and exhaust flow rate values in the Fac pulse spectrum.

3. The method for optimizing an SCR average temperature algorithm of claim 1, wherein the correction coefficient value is obtained by substituting the deviation value and the exhaust flow rate value into a Fac pulse spectrum search.

4. The method for optimizing an SCR average temperature algorithm of claim 3, wherein the Fac pulse spectrum is a raw design data curve table.

Technical Field

The invention relates to control optimization of average temperature of SCR in engine aftertreatment, in particular to an optimization method of an algorithm for calculating the average temperature of an SCR carrier according to an upstream temperature sensor and a downstream temperature sensor.

Background

There are several methods for calculating the average temperature of the carrier by the current general post-treatment SCR (Selective Catalytic Reduction).

The first method comprises the following steps: using the upstream temperature sensor value as an actual value (A), the downstream temperature sensor value as an actual value (B), and the average temperature of the SCR carrier is (A + B)/2;

and the second method comprises the following steps: and calculating an average temperature of the SCR carrier by using an upstream temperature sensor value as an actual value (A), a downstream temperature sensor value as an actual value (B) and an average temperature of the SCR carrier as (A-B)/H + B, wherein the H coefficient is obtained by searching a curve by using the deviation of A-B.

And the third is that: and (3) cutting the SCR into N slices, and calculating the temperature of each slice by using heat conservation, wherein the average temperature of the SCR carrier is the average value of all the slices.

Disclosure of Invention

The invention aims to provide an optimization method of an SCR average temperature algorithm, which is more accurate in the temperature of an SCR carrier obtained through actual temperature average values and correction coefficient values of sensors on the upstream and downstream of the SCR carrier.

In order to achieve the above object, the present invention provides an optimization method of an SCR average temperature algorithm, comprising the following steps: acquiring an actual temperature value of an upstream sensor of the SCR carrier; acquiring an actual temperature value of a downstream sensor of the SCR carrier; calculating and obtaining an average temperature value of the SCR carrier; calculating an offset value of an actual temperature value of an upstream sensor of the SCR carrier and an actual temperature value of a downstream sensor of the SCR carrier; acquiring an exhaust flow value passing through an SCR carrier; searching a corresponding correction coefficient value through the deviation value and the exhaust flow value; and calculating the temperature value of the SCR carrier through the average temperature value and the correction coefficient value.

In a preferred embodiment, the temperature value of the SCR carrier is calculated by the following formula:

the temperature value of the SCR carrier is (A + B)/2 xM; wherein A is an actual temperature value of a sensor upstream of the SCR carrier; b is an actual temperature value of a downstream sensor of the SCR carrier; m is a correction coefficient value corresponding to the (A-B) and exhaust flow rate values in the Fac pulse spectrum.

In a preferred embodiment, the correction coefficient values are obtained by substituting the offset value and the exhaust flow rate value into the Fac pulse spectrum lookup.

In a preferred embodiment, the Fac pulse spectrum is a graph of the original design data.

Compared with the prior art, the optimization method of the SCR average temperature algorithm has the following beneficial effects: the problems that the temperature condition of the carrier cannot be truly reflected and the high and low temperature condition of the SCR carrier cannot be considered in the conventional calculation mode are solved, so that the independent calibration flexibility is realized, the control precision is higher, the requirements of an actual calibration engineer are better met, and the adaptability is greatly enhanced. The method can prevent the calculation error of target ammonia storage and conversion efficiency caused by incorrect calculation of carrier temperature, influence the fluctuation of emission level and improve the emission level.

Drawings

FIG. 1 is a schematic flow diagram of an optimization method according to an embodiment of the invention.

Detailed Description

The following detailed description of the present invention is provided in conjunction with the accompanying drawings, but it should be understood that the scope of the present invention is not limited to the specific embodiments.

Throughout the specification and claims, unless explicitly stated otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element or component but not the exclusion of any other element or component.

As shown in fig. 1, an optimization method of an SCR average temperature algorithm according to a preferred embodiment of the present invention includes the following steps: acquiring an actual temperature value of an upstream sensor of the SCR carrier; acquiring an actual temperature value of a downstream sensor of the SCR carrier; calculating and obtaining an average temperature value of the SCR carrier; calculating an offset value of an actual temperature value of an upstream sensor of the SCR carrier and an actual temperature value of a downstream sensor of the SCR carrier; acquiring an exhaust flow value passing through an SCR carrier; searching a corresponding correction coefficient value through the deviation value and the exhaust flow value; and calculating the temperature value of the SCR carrier through the average temperature value and the correction coefficient value.

In one embodiment, the temperature value of the SCR carrier is calculated by the following formula:

the temperature value of the SCR carrier is (A + B)/2 xM; wherein A is an actual temperature value of a sensor upstream of the SCR carrier; b is an actual temperature value of a downstream sensor of the SCR carrier; m is a correction coefficient value corresponding to the (A-B) and exhaust flow rate values in the Fac pulse spectrum. The correction coefficient value is obtained by introducing the deviation value and the exhaust flow value into the Fac pulse spectrum search.

In some embodiments, the Fac pulse spectrum is a curve table of the original design data. That is, in the design of this solution, the curve relationship between the deviation value of the actual temperature values of the upstream and downstream sensors of the SCR carrier and the exhaust gas flow rate value passing through the SCR carrier is calculated by theoretical calculation, for example, a curve in which the deviation value is taken as the X axis and the exhaust gas flow rate value is taken as the Y axis.

In summary, in actual use of the SCR carrier, the temperature distribution is gradually decreased from upstream to downstream, and most of the adsorbed NH3 reacts with NOX to be biased to the second half. According to the temperature deviation (temperature gradient) of the SCR upstream and downstream and the exhaust flow D, the actual temperature state of the SCR carrier can be truly, dynamically and accurately reflected. The temperature gradient and the exhaust flow are used as the input of pulse spectrums, the correction coefficient is inquired, the SCR carrier temperature can be effectively and accurately calculated, the urea control is more accurate, the requirements of actual calibration engineers are better met, and the adaptability is greatly enhanced. Meanwhile, the method can prevent the calculation error of target ammonia storage and conversion efficiency caused by incorrect calculation of the carrier temperature, influence the fluctuation of emission level and improve the emission level.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical application to enable one skilled in the art to make and use various exemplary embodiments of the invention and various alternatives and modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.