JB/T 8839.2-1999 Test method for magnetoelectric pressure gauge for internal combustion engine JB/T8839.2-1999 Standard download decompression password: www.bzxz.net

Standard of the Ministry of Machinery Industry of the People's Republic of China Magnetoelectric Pressure Gauge for Internal Combustion Engines
Test Method
This standard applies to magnetoelectric pressure gauges for internal combustion engines. 1 Test Method
1.1 Appearance InspectionbzxZ.net
Observe with the naked eye in sufficient light and at a distance of 600mm. 1.2 Inspection of coating and paint layer
NJ 390.2--86
JB/T8839.2-1999
Paint layer adhesion The grid method is used to test the paint layer on the surface of the fully dried instrument, that is, 4 vertical and horizontal strokes are made with a blade, with a spacing of 1mm between each stroke, forming 9 small squares, and the paint layer in the squares should not have any delamination phenomenon. The surface color of the electroplated layer should be bright, the bonding should be firm, and there should be no obvious defects such as exposed bottom, singeing, bubbles, spots or rust. 1.3 Performance test
1.3.1 Test conditions
1.3.1.1 When checking the error of the pressure gauge indicator, the ambient temperature should be room temperature (23±5℃) and the relative humidity should not exceed 90%. 1.3.1.2 The installation position of the pressure gauge indicator is 45°. 1.8.1.8 The pressure gauge indicator should be tested in conjunction with the pressure sensor designed for it. 1.3.1.4 The test uses a DC regulated power supply. The test voltage of the pressure gauge should comply with the provisions of Table 1, and the accuracy of the voltage meter should not be lower than Class 1.5.
Rated voltage
Test voltage
Durability test voltage
14.0±0.5
1.3.1.5 The accuracy of the standard pressure gauge should not be lower than Class 0.4, and the upper limit pressure value of its scale should not be greater than 1.5 times the upper limit pressure value of the pressure gauge scale being tested.
1.3.1.6 The standard thermometer is a second-class standard mercury thermometer. 1.3.1.7 In order to be more consistent with the actual use, the sensor is allowed to be tapped. 1.3.1.8 Except for the test of changing the indicated value reading and the vibration impact test, the pressure gauge is in a non-working state. 1.3.2 Basic error test
The test is carried out by comparing with the standard pressure gauge in the 1/3 to 2/3 section of the scale indication range of the pressure gauge (no less than 2 detection points). During the test, the pressure should first be maintained at the limit pressure value on the scale for 600s, and then the pressure should be changed steadily in the order of first decreasing and then increasing. Before reading the indicated value, it should be maintained at the pressure value of the detected graduation line for no less than 120S, and the movement of the pointer should be checked at the same time.
1.3.3 Voltage influence
For rated voltage of 12V: check the indicated value at voltage of 10.8V and 15V respectively; for rated voltage of 24V, check the indicated value at voltage of 21.6V and 30V respectively. This test is only carried out on the middle limit of the scale when the pressure rises.
1.3.4 Over-test
NJ890.2—86
The pressure gauge rises to 2 times the upper limit pressure value of the scale for 2S, and then check the indicated value according to the method in 1.3.2 of this standard. 1.3.5 Temperature influence
First, check the indication value of the pressure gauge at room temperature, then put the temperature gauge indicator into a high temperature (and low temperature) box, heat (and cool) to 65±2℃ (and 40±2℃), keep warm for 4h, and then check its indication value, thus obtaining the difference between the indication value of high and low temperature and room temperature. The test is only carried out on the middle limit of the scale when the pressure rises. After the high and low temperature test, the pressure gauge should be placed at room temperature for no less than 4h, and then check its indication value according to the method of Article 1.3.2 of this standard. 1.3.6 Vibration and impact resistance test
Fix the pressure gauge indicator on the vibration test bench (and impact test bench) and put it in the normal working position, and conduct the test under working conditions.
The natural frequency of the fixture for fixing the pressure gauge indicator should be more than twice the test frequency, and the table of the vibration test bench generates sinusoidal wave vibration in the vertical direction. The inspection point for measuring acceleration should be selected near the product fixing point. Sinusoidal vibration acceleration is calculated as follows:
Where; α~—acceleration m/s2;
A-amplitude mm;
f-—vibration frequency Hz.
The impact test bench should generate the impact load of the product within the calculated pulse width of 10ms. The accuracy of vibration and impact acceleration is ±20%. After the vibration and impact test, the pressure gauge shall be externally inspected. The parts shall not be damaged and the fasteners shall not be loose. After the test, check the indicated value according to the method of 1.3.2. 1.3.7 Insulation dielectric strength test
The ambient temperature during the test is 23 ± 5℃. When it is used as a type test, it should be carried out after the vibration test. The capacity of the test transformer shall not be less than 0.5kVA, and the voltage shall be evenly increased to the test value. After reaching the test voltage value, it shall last for 60S, and then the voltage shall be evenly reduced to zero. When checking the insulation dielectric strength test during the production process, it is allowed to apply full voltage at one time. 1.3.8 Moisture resistance test
Put the pressure gauge in a constant temperature and humidity chamber with a temperature of 40±2℃ and a relative humidity of 90%~95%, and take it out after 48 hours. After the product is taken out of the test chamber, the insulation dielectric strength should be tested according to Article 1.3.7 within 15 minutes. The volume of the constant temperature and humidity chamber shall not be less than 3 times the volume of the product. The product should be placed in a constant temperature chamber with a temperature of 40±2℃ for 3 hours before being placed in the test chamber.
1.3.9 Splash test
Put the pressure gauge indicator in an appropriate position in the splash test chamber and conduct the test on a special splash test equipment. Use a water column with a pressure of 0.3~0.4MPa, the water level rise height (i.e. precipitation) per minute is 5mm, the distance between the nozzle and the product is not more than 500mm, the test is 1h, after the test, wipe off the water droplets on the surface of the product, and inspect it within 15 minutes. If there are no water drops in the pressure gauge indicator, it is considered qualified.
1.3.10 Dust test
Put the pressure gauge indicator in the working position and in the non-working state, and conduct the test on the special dust test equipment. Put the pressure gauge indicator on the bracket in the dust chamber with a volume of 0.5~1m3, use compressed air (blow for 7s every 15min) or blow with a fan to make the powder in the dust chamber in a flying state. The powder is talcum powder or 500 cement, the dosage is 20kg/m2, and the test time is 1h. After the test, clean the outside of the indicator and observe it with eyes. If there is no dust entering the gauge, it is qualified. 6
1.3.11 Durability test
NJ 390.2-86
Install the pressure gauge on the special test equipment, and conduct the pressure cycle alternation test at a frequency of not less than 0.5Hz. The load alternation range is 20%~80% of the upper limit of the measurement, and a total of 100,000 times are carried out. After the test, check the indicated value according to the method in Article 1.3.2 of this standard.
2 Acceptance rules
2.1 Factory inspection
Each pressure gauge shall be inspected by the factory inspection department according to Articles 2.2.1 to 2.2.5, 2.3, 2.4.1 to 2.4.3 of NJ390.1-86 "Technical conditions for magnetic pressure gauges for internal combustion engines" before leaving the factory. Only after passing the inspection can it leave the factory and be accompanied by a product certificate or mark. Items not included in the factory inspection shall also comply with the provisions of NJ390.1-86. 2.2 Type test
In the following cases, the pressure gauge shall be type tested according to all the technical requirements in NJ390.1-86. a. Trial-produced pressure gauge,
b. When there are major changes in the design, process, and materials used of the pressure gauge; when the pressure gauge is discontinued for more than one year and put into production again; c.
d. Pressure gauges produced in batches shall be tested at least once a year. The temperature gauges for type testing shall be randomly selected from the products leaving the factory, and no less than 3 pieces shall be tested each time. If any unqualified items appear, the test shall be doubled according to the above-mentioned number. If all the results are qualified in the second test, the type test of the pressure gauge is qualified. Pressure gauges for durability testing may be sampled separately.
Additional notes:
This standard was proposed and coordinated by the Luoyang Tractor Research Institute. This standard was drafted by the Chengdu Instrument Factory. Drafter of this standard: Zhu Shizhen
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