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Engine airway performance directly affects engine performance, introduces steady flow test bench, establishes standard parameters of cylinder head air passage, and discusses the evaluation method of airway flow impact on engine performance, which can quickly analyze and determine the influencing factors of airway to engine power. Through the airway flow test, the factors of the cylinder head analysis are clarified, and after the countermeasures are formulated, the effectiveness of the countermeasures is judged, and the performance verification is finally performed by the bench test.
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The main points and structure of the steady flow test bench
According to the requirements of the mass production problem, the airway flow coefficient test is mainly judged, and the eddy current ratio and the tumble ratio test capability are retained for the subsequent development requirements. The structure diagram is shown in Fig. 1.
Figure 1 steady flow test bench structure
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1. Test bench main body 2. Secondary voltage regulator box 3. U-shaped tube 4. Blade type eddy current anemometer 5. Eddy current simulation cylinder 6. Lift sensor 7. Valve lift adjustment motor 8. Cylinder head 9. Tumble flow simulation Cylinder 10. Blade type tumble anemometer 11. Differential pressure sensor 12. Pipe 13. Vortex flowmeter 14. Voltage regulator 15. Valve 16. High pressure centrifugal fan...
Test bench verification
The test bench verification mainly verifies the inlet and exhaust flow test function and test accuracy. The mass production cylinder head, the same air passage, the same test conditions, the same operation are subjected to multiple tests, and the accuracy is judged according to the repeatability.
From the results of Fig. 2 and Fig. 3, the deviation of the flow coefficient under the lift of 1~10mm is within ±0.5%, and the deviation of the average flow coefficient is also less than ±0.5%, which meets the accuracy requirement of ±1%.
Figure 2 Five-time intake test repeatability Figure 3 Five-time exhaust test repeatability
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Method for evaluating inlet flow characteristics
In the steady flow evaluation method, Ricardo evaluation method is widely used in China. In the absence of standard data available for use, the standard data of the cylinder head product is established by the method of batch testing of the mass production cylinder head as the basis for judgment.
......
Head airway established <br> <br> standard data to a four-cylinder engine head, for example, production extraction head 10, were tested in the same flow coefficient and mean airway flow coefficient at each lift, remove Among them, the jump point data is calculated as the standard flow data of the cylinder head. Table 1 is the judgment criterion of each lift flow coefficient. When the target cylinder head is analyzed, the actual flow coefficient of the air passage under each lift is tested. Compared with the standard data, the problem of airway circulation ability can be judged according to the judgment criteria. Figure 4 shows the standard flow curve. Through the drawing of the flow coefficient curve of each lift, the area with poor airflow capacity can be visually judged.
Table 1 Airway flow coefficient reference value Figure 4 Airway flow coefficient standard curve
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Applications
When developing a four-cylinder machine, there was a shortage of prototype power (since it was a newly developed model, the performance data was omitted here). The blank used in the domestic cylinder head was the same as the KD piece, and it was processed only in China. The lack of power has not appeared in foreign countries, and the blank problem can be basically eliminated, and the scope of influence is limited to the processing field. Firstly, the airway flow rate test of the cylinder head is carried out to determine the influence factors of the airflow flow on the power shortage. The test results are as follows. Table 2 shows the inlet test data, and Table 3 shows the exhaust test data.
Table 2 Object cylinder head inlet flow test results
Table 3 Object cylinder head exhaust flow test results Table 4 Domestic cylinder head exhaust side section difference confirmation From the measured results of the step difference: 80% of the domestic cylinder head in the exhaust valve section difference exceeds the management value, and there is a significant difference with the KD cylinder head. Therefore, according to the analysis results, the countermeasures are as follows: clear the burrs near the intake valve and adjust the size of the machining tool on the exhaust side. The results of the step difference test after the countermeasure are shown in Table 5.
Table 5 Confirmation of the difference in the exhaust side of the domestic cylinder head (after the countermeasure)
From the results of the step confirmation, the adjusted step level has been improved, which is basically equivalent to the KD piece.
The cylinder head after the countermeasure is subjected to a flow test, and the effectiveness of the countermeasure is judged by the airway flow test data. The test results are shown in Tables 6 and 7.
Table 6 Domestic cylinder head inlet flow test results (after countermeasures)
Table 7 Domestic cylinder head exhaust flow test results (after countermeasures)
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Table 8 Comparison of the front and rear data of the 45° surface width of the exhaust side. Figure 5 Confirmation of the seat hole and seat machining position...
Conclusion <br> <br> through the establishment of an airway flow test, evaluation and practical application, it can be concluded:
(1) The accuracy of the airway flow test rig can meet the requirements for use.
......
Engine airway performance directly affects engine performance, introduces steady flow test bench, establishes standard parameters of cylinder head air passage, and discusses the evaluation method of airway flow impact on engine performance, which can quickly analyze and determine the influencing factors of airway to engine power. Through the airway flow test, the factors of the cylinder head analysis are clarified, and after the countermeasures are formulated, the effectiveness of the countermeasures is judged, and the performance verification is finally performed by the bench test.
......
The main points and structure of the steady flow test bench
According to the requirements of the mass production problem, the airway flow coefficient test is mainly judged, and the eddy current ratio and the tumble ratio test capability are retained for the subsequent development requirements. The structure diagram is shown in Fig. 1.
Figure 1 steady flow test bench structure
......
1. Test bench main body 2. Secondary voltage regulator box 3. U-shaped tube 4. Blade type eddy current anemometer 5. Eddy current simulation cylinder 6. Lift sensor 7. Valve lift adjustment motor 8. Cylinder head 9. Tumble flow simulation Cylinder 10. Blade type tumble anemometer 11. Differential pressure sensor 12. Pipe 13. Vortex flowmeter 14. Voltage regulator 15. Valve 16. High pressure centrifugal fan...
Test bench verification
The test bench verification mainly verifies the inlet and exhaust flow test function and test accuracy. The mass production cylinder head, the same air passage, the same test conditions, the same operation are subjected to multiple tests, and the accuracy is judged according to the repeatability.
From the results of Fig. 2 and Fig. 3, the deviation of the flow coefficient under the lift of 1~10mm is within ±0.5%, and the deviation of the average flow coefficient is also less than ±0.5%, which meets the accuracy requirement of ±1%.
Figure 2 Five-time intake test repeatability Figure 3 Five-time exhaust test repeatability
......
Method for evaluating inlet flow characteristics
In the steady flow evaluation method, Ricardo evaluation method is widely used in China. In the absence of standard data available for use, the standard data of the cylinder head product is established by the method of batch testing of the mass production cylinder head as the basis for judgment.
......
Head airway established <br> <br> standard data to a four-cylinder engine head, for example, production extraction head 10, were tested in the same flow coefficient and mean airway flow coefficient at each lift, remove Among them, the jump point data is calculated as the standard flow data of the cylinder head. Table 1 is the judgment criterion of each lift flow coefficient. When the target cylinder head is analyzed, the actual flow coefficient of the air passage under each lift is tested. Compared with the standard data, the problem of airway circulation ability can be judged according to the judgment criteria. Figure 4 shows the standard flow curve. Through the drawing of the flow coefficient curve of each lift, the area with poor airflow capacity can be visually judged.
Table 1 Airway flow coefficient reference value Figure 4 Airway flow coefficient standard curve
......
Applications
When developing a four-cylinder machine, there was a shortage of prototype power (since it was a newly developed model, the performance data was omitted here). The blank used in the domestic cylinder head was the same as the KD piece, and it was processed only in China. The lack of power has not appeared in foreign countries, and the blank problem can be basically eliminated, and the scope of influence is limited to the processing field. Firstly, the airway flow rate test of the cylinder head is carried out to determine the influence factors of the airflow flow on the power shortage. The test results are as follows. Table 2 shows the inlet test data, and Table 3 shows the exhaust test data.
Table 2 Object cylinder head inlet flow test results
Table 3 Object cylinder head exhaust flow test results Table 4 Domestic cylinder head exhaust side section difference confirmation From the measured results of the step difference: 80% of the domestic cylinder head in the exhaust valve section difference exceeds the management value, and there is a significant difference with the KD cylinder head. Therefore, according to the analysis results, the countermeasures are as follows: clear the burrs near the intake valve and adjust the size of the machining tool on the exhaust side. The results of the step difference test after the countermeasure are shown in Table 5.
Table 5 Confirmation of the difference in the exhaust side of the domestic cylinder head (after the countermeasure)
From the results of the step confirmation, the adjusted step level has been improved, which is basically equivalent to the KD piece.
The cylinder head after the countermeasure is subjected to a flow test, and the effectiveness of the countermeasure is judged by the airway flow test data. The test results are shown in Tables 6 and 7.
Table 6 Domestic cylinder head inlet flow test results (after countermeasures)
Table 7 Domestic cylinder head exhaust flow test results (after countermeasures)
......
Table 8 Comparison of the front and rear data of the 45° surface width of the exhaust side. Figure 5 Confirmation of the seat hole and seat machining position...
Conclusion <br> <br> through the establishment of an airway flow test, evaluation and practical application, it can be concluded:
(1) The accuracy of the airway flow test rig can meet the requirements for use.
......
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