CN112378664A

CN112378664A - Method for simulating non-road mobile machinery vehicle-mounted emission test on engine rack

Info

Publication number: CN112378664A
Application number: CN202010527969.XA
Authority: CN
Inventors: 杨俊�; 陈曦; 张晏飞; 叶超; 解亮
Original assignee: Xiangyang Daan Automobile Test Center Co Ltd
Current assignee: Xiangyang Daan Automobile Test Center Co Ltd
Priority date: 2020-06-11
Filing date: 2020-06-11
Publication date: 2021-02-19

Abstract

The invention relates to a method for simulating non-road mobile machinery vehicle-mounted emission test on an engine bench, which comprises the following three steps: data acquisition, data processing and programming and execution. And the data acquisition stage relates to the external characteristic data, the operation data and the field environment data of the engine. A data processing stage comprising data conversion and data validity analysis; and when data are converted, the load factor and the maximum torque value at the same rotating speed are converted into corresponding torque values. And during data validity analysis, a group of data after data conversion treatment represents a cycle working condition, and the ratio of accumulated work to the effective work base window is calculated. And in the programming and executing stage, the collected, processed and analyzed data is utilized to program an automatic operation program in the rack control computer, and pollutant emission results in the processes of measurement, recording and calculation are recorded. The method has the advantages of simplicity, convenience in execution, high data reliability and good test repeatability.

Description

Method for simulating non-road mobile machinery vehicle-mounted emission test on engine rack

Technical Field

The invention relates to the technical field of special motor vehicle detection, in particular to an emission test method for simulating non-road mobile machinery vehicle-mounted method on an engine bench.

Background

The non-road mobile machinery has the defects of various types, wide application, complex working conditions, higher energy consumption, wide machine type matching and environmental friendliness, so that the products have long design and development period, high production and manufacturing cost, strict pollutant emission requirement and high detection test difficulty.

Disclosure of Invention

The invention aims to provide a method for simulating the vehicle-mounted emission test of the non-road mobile machinery on an engine rack, which can effectively simulate the actual working condition of the non-road mobile machinery, measure the exhaust pollutants in the process at the same time to calculate and obtain the simulated emission result, effectively shorten the development period and ensure that the test data has good repeatability.

The technical scheme of the invention is as follows: a method for simulating non-road mobile machinery vehicle-mounted emission test on an engine bench is designed, and comprises the following three steps: step one, data acquisition; step two, data processing; and step three, programming and executing.

Step one, data acquisition.

The method comprises the steps of testing and recording external characteristic data of an engine on a rack, then installing the engine on a non-road mobile machine matched with the engine, and collecting engine operation data including rotating speed, load rate and environment condition data of an operation site in an actual operation process of the non-road mobile machine within a period of time.

And step two, data processing.

And converting the load rate in the data acquired in the first step into a torque value: and multiplying the load rate of the engine at a certain rotating speed in the mechanical actual operation process acquired in the first step by the maximum torque value corresponding to the rotating speed in the characteristic data outside the engine pedestal to obtain the torque value corresponding to the load rate of the engine at the rotating speed in the mechanical actual operation process. By analogy, torque values corresponding to the load factors of the engine at various rotating speeds during the actual operation of the machine can be obtained.

And (3) data validity analysis: and taking a group of data processed in the second step as a representative cycle working condition, and calculating the ratio of the accumulated work to the effective work base window. According to the national environmental protection standard HJ1014-2019 'technical requirement for pollutant emission control of non-road diesel mobile machinery' of the people's republic of China,' when the accumulated work of the testing machinery reaches 5-7 times of the NRTC circulating work of the diesel engine or the testing time reaches 2 hours, the test is terminated; the effective power base window accounts for more than 50% of all the power base windows, otherwise, the test is invalid, and the test scheme is adjusted to restart the test. If one of the accumulated work and the effective work base window ratio does not meet the requirement, the time length of the collected working condition or the working condition of the machine is adjusted until a group of engine working condition data meeting the requirement is obtained.

Step three: programming and executing.

When the program is programmed, the engine is installed on the rack again, and the automatic operation program is programmed in the control computer of the engine rack by using the collected, processed and analyzed data.

When the program is operated, the engine operates one by one second according to the working condition in the automatic program, the bench test equipment measures and records the relevant data of the exhaust pollutants of the engine, and the emission value obtained by calculation is a test result: i.e., the results of the non-road mobile machine on-board emissions test simulated on the gantry.

The beneficial technical effects of the invention are as follows: by adopting the method, the working condition of the engine in the actual operation process of the non-road mobile machinery can be accurately simulated on the engine rack. If environmental conditions and other key influence factors in the non-road mobile mechanical vehicle-mounted emission test process can be comprehensively and accurately simulated on the engine rack, the emission test result can also be accurately simulated. The invention also has the advantages of simple method, convenient execution, high data reliability and good test repeatability.

Drawings

Fig. 1 is a control flow chart.

Detailed Description

The invention is further illustrated by the following examples.

First, the procedure.

Step one, data acquisition.

The method comprises the following steps of installing a non-road third-stage electric control diesel engine on an engine rack, measuring and recording external characteristic data, and specifically comprises the following steps: the fuel injection pump is set at a full-load position, the rotating speed of the engine is measured from low idle speed to high idle speed at intervals of 100r/min, and the maximum torque value corresponding to each rotating speed is recorded.

Install this engine on the air compressor machine, use PEMS equipment to gather the operating data of this engine in the air compressor machine actual operation in-process in a period of time, include: the rotating speed and the corresponding load factor; environmental condition data for a work site, comprising: intake air temperature and humidity, ambient temperature and humidity, atmospheric pressure, altitude.

And step two, data processing.

Multiplying the load rates (B1, B2 and B3 … … Bn) corresponding to the same group of internal rotation speeds (A1, A2 and A3 … … An) of the engine during the actual operation of the air compressor acquired in the step one by the maximum torque values (C1, C2 and C3 … … Cn) of the engine at the rotation speeds in the bench outside characteristic data to obtain torque values (D1, D2 and D3 … … Dn) corresponding to the load rates of the engine during the actual operation of the air compressor at each rotation speed.

Taking a group of data processed in the step two as a representative cycle working condition, calculating the ratio of the accumulated work to the effective work base window, and judging whether the accumulated work and the effective work base window meet the requirements according to the following judgment basis: according to the national environmental protection standard HJ1014-2019 'technical requirement for pollutant emission control of non-road diesel mobile machinery' of the people's republic of China,' when the accumulated work of the testing machinery reaches 5-7 times of the NRTC circulating work of the diesel engine or the testing time reaches 2 hours, the test is terminated; the effective power base window accounts for more than 50% of all the power base windows, otherwise, the test is invalid, and the test scheme is adjusted to restart the test.

The window with the average power of the window being more than 20% of the maximum power of the engine is an effective power base window, and the effective power base window accounts for more than or equal to 50% of all the power base windows. If the proportion of the effective power base window is below 50%, the evaluation will continue using the lower power threshold. The window average power threshold requirement is gradually reduced in steps of 1% until the proportion of the effective power base window reaches 50%. In any case, the power threshold value must not be less than 10% at minimum. If the proportion of the valid power base window is still less than 50% at the minimum power threshold, the test is invalid.

If the accumulated work does not meet the standard requirements, the work load can be increased or the work time can be prolonged until a set of engine working condition data meeting the requirements is obtained.

Step three: programming and executing.

When programming, the engine is remounted on the rack, and the data obtained during the working condition/power calculation and analysis is utilized to program an automatic operation program in the engine rack control computer. When the program is operated, the engine operates one by one second according to the working condition in the automatic program, the bench test equipment measures and records the relevant data of the exhaust pollutants of the engine, and the emission value obtained by calculation is the test result: namely, the vehicle-mounted engine emission simulation test detection value for the non-road mobile machinery.

And a second part, controlling the flow.

Firstly, performing transient external characteristic test on an engine pedestal, and acquiring external characteristic data, wherein the rotating speed range is from idle speed to highest empty vehicle rotating speed.

Step two, collecting working condition data: the method comprises the steps of collecting engine operation condition data in the actual operation process of machinery within a period of time.

And thirdly, converting the working condition data acquired in the previous step into a group of engine rotating speed and torque data according to the transient external characteristic data.

Step four, if the rotating speed and torque data of the previous step do not meet the requirements, the data are transmitted to the working condition data acquisition of the step two for data reprocessing; and if the rotating speed and the torque data of the previous step meet the requirements, transmitting to the next step.

And fifthly, inputting the rotating speed and torque data which are in accordance with the requirements and are transmitted in the previous step into a rack computer, and compiling an operation condition program.

And sixthly, running the program written in the previous step on the engine pedestal, and synchronously measuring exhaust pollutants and other data.

Seventhly, analyzing and processing the exhaust pollutants and other data transmitted in the previous step, if the emission result does not reach the standard, adjusting engine control parameters, and if the performance parameters of the engine are not adjusted, operating the working condition program again and collecting the exhaust pollutants and other data; and if the performance parameters of the engine are adjusted, returning to the first step, and acquiring the bench data again. And if the emission result reaches the standard, the next step is carried out.

And eighthly, mounting the engine on the non-road mobile machine to perform an actual vehicle-mounted emission test.

Claims

1. A method for simulating non-road mobile machinery vehicle-mounted emission test on an engine bench comprises the following three steps: the method comprises the following steps of firstly, simulating data acquisition, secondly, processing working condition data, and thirdly, programming and executing; the method is characterized in that: the working condition data processing comprises the following steps: converting working condition data, and calculating and analyzing working condition/power;

during working condition data conversion, rotation speed/load rate/maximum torque value/torque value conversion is completed in a grouping mode, analog data collection is carried out in a grouping mode, rotation speed, load rate, maximum torque value and torque value in the same group are correspondingly set, the rotation speed is A1, A2 and A3 … … An, the load rate is B1, B2 and B3 … … Bn, the maximum torque value is C1, C2 and C3 … … Cn, the torque value is D1, D2 and D3 … … Dn, the load rate is multiplied by the maximum torque value at the corresponding rotation speed to obtain the torque value corresponding to the load rate at each rotation speed, and the processed group of data comprises n pairs of engine rotation speed and torque data;

during working condition/power calculation and analysis, calculating the ratio of accumulated work to effective work base window, and performing test effect pre-evaluation; when the ratio of the accumulated work to the effective work base window is calculated, a group of data after the working condition data conversion processing is taken as a representative cycle working condition, the ratio of the accumulated work to the effective work base window is calculated, the accumulated work is equal to 5-7 times of the NRTC test cycle work, if the accumulated work is not satisfied, the operation load can be increased, or the operation time can be prolonged; the effective work base window is limited in that the average power of the window is 20% greater than the maximum power of the engine, and the effective work base window accounts for 50% or more of all the work base windows; when the test effect is pre-evaluated, if the proportion of the effective power base window is lower than 50%, a lower power threshold value is used for continuing evaluation, the requirement of the average power threshold value of the window is gradually reduced by taking 1% as a step length until the proportion of the effective power base window reaches 50%, and in any case, the minimum power threshold value cannot be smaller than 10%; if the proportion of the valid power base window is still less than 50% at the minimum power threshold, the test is invalid.